Phosphodiesterase 3 (PDE3) inhibitors

Abstract

This invention describes novel PDE3 inhibitors for treating cardiovascular diseases, including myxomatous mitral valve disease, congestive heart failure, and / or asymptomatic heart failure, in animals, particularly dogs.

Description

[Technical Field]

[0001] This invention describes a novel multi-phase cardiac stressor that inhibits phosphodiesterase 3 (PDE3) from calcium sensitization and reduces the likelihood of arrhythmias, for the treatment of cardiovascular diseases including myxomatous mitral valve disease, congestive heart failure, and / or asymptomatic heart failure in animals, as well as a process for preparing the same, its composition, and a method of use thereof. [Background technology]

[0002] Congestive heart failure (CHF) is a leading cause of death in patients with heart disease. Phosphodiesterases are a class of intracellular enzymes involved in the hydrolysis of cyclic adenosine monophosphate (c-AMP) and cyclic guanosine monophosphate (c-GMP), which are involved in regulating important cellular functions such as secretion, contraction, metabolism, and growth. Based on their structure and substrate specificity, PDE enzymes can be grouped into 11 different families, defined as PDE1 to PDE11.

[0003] Each PDE isozyme possesses a conserved C-terminal catalytic domain and a unique N-terminal regulatory domain. These isozymes are found in different animal tissues and cells, including smooth muscle, brain, heart, lung, platelets, and lymphocytes. Of all the subtypes of PDE, PDE3 is primarily expressed in cardiomyocytes and platelets. The mammalian PDE3 family consists of two isoforms (A and B) that have similar pharmacological properties but can be distinguished based on their expression profiles and affinity for cGMP. PDE3A is present in platelets, kidneys, vascular smooth muscle, heart, and oocytes. PDE3B is localized in adipocytes, hepatocytes, vascular smooth muscle, developing sperm, kidneys, B cells, T lymphocytes, and macrophages. PDE3 is specific to c-AMP and does not affect c-GMP or calmodulin. Therefore, inhibition of PDE3 isoenzymes in cardiovascular tissue results in high levels of c-AMP and the resulting inotropic effect, thereby driving myocardial contraction (anisotropic) and smooth muscle vasodilation.

[0004] Myxomatous mitral valve disease (MMD) is a leading cause of cardiovascular disease in dogs. MMVD causes mitral valve dysfunction, leading to mitral regurgitation, which contributes to sodium and water retention, activation of the neurohormonal system, volume overload, and ultimately congestive heart failure (CHF). Synonymous medical terms for MMVD as used herein include mitral valve disease (MVD), degenerative mitral valve disease (DMVD), chronic valve disease (CVD), chronic valvular heart disease (CVHD), and atrioventricular valve insufficiency (AVVI). The pathophysiology of MMVD involves differentiation and activation of the normally resting mitral valve into a more active myofibroblast phenotype, which mediates many histological and molecular changes in the valve tissue. MMVD is present in approximately 30% of all dogs over 10 years of age and is the most frequent cause of CHF in dogs. MMVD is most common in small breeds such as Cavalier King Charles Spaniels, Chihuahuas, Maltese, Pekingese, and Toy and Miniature Poodles. The natural history of the disease is adult onset, variable progression with age, and one of the final developments of CHF in dogs with severe disease. Current treatments for MMVD include the use of angiotensin enzyme inhibitors, diuretics, vasodilators, and positive inotropic agents.

[0005] Previous citations (1985-1988) described benzothiazolon (US4562190A), thiadiazinon (US4916128A), and pyridazinon (US4647564A) as drugs with useful properties as antihypertensive, antithrombotic, cardiac tonic, and positive inotropic agents that can be used to treat heart failure. PDE3 inhibition data were not presented in these prior citations. In addition, numerous non-spirocyclic cardiac tonics are described in the Journal of Medicinal Chemistry (JMC), Vol. 35, 1992, pp. 163-172, and PDE3 IC 50 The values ​​range from approximately 0.17 to 66.0 μM (Table IX), and the reported pimobendan IC50 is... 50The concentration was 0.56 μM (560 nM). According to a JMC citation, small changes in molecular structure can have very different effects on enzyme (PDE and ATPase) inhibition and / or calcium sensitization properties. For example, 0.52 μM PDE3 IC 50 It was shown that indolinidane with a value lacked calcium sensitizing properties, and that the introduction of a sulfur atom to the pyridazine ring preferred the desired activity, with substitution of the indorone moiety also appearing essential. This is shown in Table IV using alkyl substitutions on the indole ring. According to JMC, the addition of a sulfur-containing spirocyclic ring to indole increased calcium sensitizing activity 30-fold, but its effectiveness as an inotropic agent in vivo was low. Therefore, it was taught that the requirements for achieving the calcium sensitizing effect are: 1) the indorone and heterocyclic moieties of the molecule must be able to achieve relative coplanarity, 2) the heterocyclic moiety must contain a sulfur (or selenium) atom, and 3) a substituent (preferably a bulky group) is required at the 3-position of the indoline ring. In contrast, it was shown that the S atom and / or bulky group are not required to achieve this dual activity. Furthermore, it was found that the addition of a halogen atom at the 7-position of oxyndol-containing molecules can induce calcium sensitizing properties and / or increase PDE3 inhibition. Therefore, the compounds of the present invention are calcium sensitizers that possess desired PDE3 inhibitory activity at nanomolar concentrations and are observed to have a positive effect in contractility assays. As described by Nadler G., et al. in the European Journal of Medicinal Chemistry (1996), Vol 31, pp. 805-8120, in pyridazinone and thiadiazinon cardiac stimulants having one chiral center, PDE inhibitory activity is generally present in one enantiomer (e.g., the (S) configuration in thiadiazinon and the (R) configuration in pyridazinone), while myofibrillar calcium sensitivity enhancing activity is present in the opposite configuration. To date, research and development of these bipolar invertebrates appears to have drastically decreased, as no new compounds have actually been described for at least 28 years.

[0006] In fact, the most commonly used inotropic compound currently sold for animal heart failure is pimobendan, which is a racemate. Pimobendan is a benzimidazole-pyridazinone derivative that has been used for about 20 years to treat congestive heart failure (CHF) caused by dilated cardiomyopathy (DCM) or DMVD in animals. The positive inotropic effect of pimobendan is mediated by a combination of increased c-AMP-mediated PDE3 inhibition and sensitization of the cardiac contractile apparatus to intracellular calcium. Pimobendan was first described in U.S. Patent No. US4361563A and was first published in an equivalent Australian patent application (AU197950279A) in February 1980. Pimobendan is orally administered to dogs twice a day at a dose of 0.5 mg / kg / day. Pimobendan is safe and well-tolerated, but must be administered chronically twice a day (q12h), which can lead to some common safety issues in animals such as racing or abnormal heartbeats, bleeding or bruising, gastrointestinal disorders, jaundice, rash and skin flushing, and is known to induce valvular lesions in asymptomatic MVD patients. In addition, pimobendan should not be used in cases of hypertrophic cardiomyopathy or aortic stenosis. Chronic BID administration can also lead to insufficient dosing compliance. As with many commercially available products, there is always a need for newer, safer, and more effective drugs to treat each disease class. The present invention describes a novel dual-phase cardiotonic agent that inhibits PDE3 at nanomolar concentrations and has a positive effect on contractility, which is a measure of calcium sensitization, and / or inhibition of platelet aggregation for the useful treatment of cardiovascular diseases including MMVD, CHF, and / or asymptomatic heart failure in animals, preferably dogs.

Summary of the Invention

[0007] In one aspect of the invention, it is a novel PDE3 receptor antagonist useful for the treatment of mitral valve disease and congestive heart failure in animals, particularly dogs. In one aspect, 8-(2-Methoxypyridin-4-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinolin-2(1H)-one (1), 6-(4-Methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-8-(thiazol-2-yl)-3,4-dihydroquinolin-2(1H)-one (2), 8-(2-Methoxythiazol-5-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinolin-2(1H)-one (4), 7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indolin-2-one (6), 7-(4-Chlorophenyl)-5-(6-oxo-1,6-dihydropyridazin-3-yl)indolin-2-one (7), 7’-Chloro-5’-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropane-1,3’-indolin]-2’-one (8), 8-(4-Chlorophenyl)-6-(6-oxo-1,6-dihydropyridazin-3-yl)-3,4-dihydroquinolin-2(1H)-one (9), 8-(3-Fluorophenyl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinolin-2(1H)-one (12), 6-(4-Methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-8-(pyridin-3-yl)-3,4-dihydroquinolin-2(1H)-one (13), 3,3-Dimethyl-5-(4-methyl-6-oxo-1,6-dihydropyridazin-3-yl)-7-(thiazol-4-yl)indolin-2-one (17), 9-(6-Methoxypyridin-3-yl)-7-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1,3,4,5-tetrahydro-2H-benzo[b]azepin-2-one (18), 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(19), 7-Bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(23), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(24), 7-Chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one(25), 7-Fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one(26), 7-Fluoro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one (27), 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropane-1,3'-indoline]-2'-one(28), 4-Chloro-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)benzo[d]thiazole-2(3H)-one(29), 6-(2-amino-4-chlorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(30), 6-(2-amino-4-fluorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(31), 7-Bromo-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indoline-2-one(32), (R)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (33), 6-(4-fluoro-2-(methylamino)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(34), 8-Chloro-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)quinoline-2(1H)-one(35), 6-(8-chloro-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one (35a), 7-Chloro-6-fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one(36), 6-(4-fluoro-2-(3-hydroxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(37), 2-amino-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)benzo[d]thiazole-4-carbonitrile (38), 7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)isoindorin-1-one (39), 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-2-oxo-1,2-dihydroquinoline-8-carbonitrile (40), 2-Hydroxy-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)quinoline-8-carbonitrile (40a), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-1-one (41), 4-Chloro-1-methyl-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1,3-dihydro-2H-benzo[d]imidazole-2-one (42), 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)spiro[cyclobutan-1,3'-indoline]-2'-one(43), 7-Chloro-3,3-dimethyl-5-(6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(44), 6-(8-bromo-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(45), 6-(4-fluoro-2-(((1-methyl-1H-pyrazole-4-yl)methyl)amino)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(46), 6-(7-chloro-3-methyl-1H-indazole-5-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(47), 6-(8-cyclopropyl-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(48), 6-(2-(3-methoxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(49), 7-Fluoro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (50), (S)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-2-one(51), 4-Chloro-6-(6-oxo-1,6-dihydropyridazine-3-yl)benzo[d]thiazole-2(3H)-one(52), 5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2-oxoindoline-7-carbonitrile (53), 4-methyl-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one(55), 4-Chloro-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one(56), 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (57), 5-(7'-chloro-2'-oxospiro[cyclopropane-1,3'-indoline]-5'-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(58), 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (59), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (61), 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(62), 6-methyl-5-(7-(4-(methylsulfonyl)phenyl)-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(63), 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(66), 5-(3,3-dimethyl-2-oxo-7-(thiazole-4-yl)indoline-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(68), 5-(7-(4-chlorophenyl)-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(71), 5-(2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(72), 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(73), 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (74), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (75), 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(76), 5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2-oxoindoline-7-carbonitrile(77), (S)-5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (78), 5-(7-chloro-1-oxoisoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (79), 5-(7-chloro-3,3-dimethyl-1-oxoisoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (80), 5-(8-chloro-2-hydroxyquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (81), 5-(7-chloro-2,2-dioxide-1,3-dihydrobenzo[c]isothiazol-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(82), 6-methyl-5-(8-methyl-2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(83), 4-Chloro-6-(2-oxo-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine-5-yl)benzo[d]oxazole-2(3H)-one(84), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one(85), 7-Chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one (86), 6-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,4-dihydro-1,8-naphthyridine-2(1H)-one(87), 4-Chloro-6-(5-oxo-4,5-dihydro-1,3,4-thiadiazole-2-yl)benzo[d]thiazol-2(3H)-one(88), and A PDE3 inhibitory compound (Example #), its stereoisomer, and veterinarily acceptable salt thereof, selected from the group consisting of 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3,4-thiadiazole-2(3H)-one (89).

[0008] In another embodiment, 8-(2-methoxypyridine-4-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one(1), 7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(6), 7'-Chloro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)spiro[cyclopropane-1,3'-indoline]-2'-one(8), 8-(4-chlorophenyl)-6-(6-oxo-1,6-dihydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one(9), 8-(3-fluorophenyl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one(12), 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-8-(pyridine-3-yl)-3,4-dihydroquinoline-2(1H)-one(13), 9-(6-methoxypyridine-3-yl)-7-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-1,3,4,5-tetrahydro-2H-benzo[b]azepine-2-one(18), 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(19), 7-Bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(23), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(24), 7-Chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one(25), 7-Fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one(26), 7-Fluoro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one (27), 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropane-1,3'-indoline]-2'-one(28), 6-(2-amino-4-chlorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(30), 6-(2-amino-4-fluorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(31), 7-Bromo-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indoline-2-one(32), (R)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (33), 6-(4-fluoro-2-(methylamino)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(34), 8-Chloro-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)quinoline-2(1H)-one(35), 6-(8-chloro-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one (35a), 7-Chloro-6-fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one(36), 6-(4-fluoro-2-(3-hydroxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(37), 2-amino-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)benzo[d]thiazole-4-carbonitrile (38), 7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)isoindorin-1-one (39), 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-2-oxo-1,2-dihydroquinoline-8-carbonitrile (40), 2-Hydroxy-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)quinoline-8-carbonitrile (40a), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-1-one (41), 4-Chloro-1-methyl-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1,3-dihydro-2H-benzo[d]imidazole-2-one (42), 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)spiro[cyclobutan-1,3'-indoline]-2'-one(43), 7-Chloro-3,3-dimethyl-5-(6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(44), 4-Chloro-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one(56), 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (57), 5-(7'-chloro-2'-oxospiro[cyclopropane-1,3'-indoline]-5'-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(58), 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (59), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (61), 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(62), 6-methyl-5-(7-(4-(methylsulfonyl)phenyl)-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(63), 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(66), 5-(7-(4-chlorophenyl)-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(71), 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(73), 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (74), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (75), 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(76), 5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2-oxoindoline-7-carbonitrile(77), (S)-5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (78), 5-(7-chloro-1-oxoisoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (79), 5-(7-chloro-3,3-dimethyl-1-oxoisoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (80), 6-methyl-5-(8-methyl-2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(83), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one (85), and A PDE3 inhibitor selected from the group consisting of 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one (86) (Example #), its stereoisomers, and veterinary-acceptable salts thereof.

[0009] In another embodiment, 8-(3-fluorophenyl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one(12), 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(19), 7-Bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(23), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(24), 7-Chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one(25), 7-Fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one(26), 7-Fluoro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one (27), 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropane-1,3'-indoline]-2'-one(28), 6-(2-amino-4-chlorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(30), 6-(2-amino-4-fluorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(31), 7-Bromo-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indoline-2-one(32), (R)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (33), 4-Chloro-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one(56), 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (57), 5-(7'-chloro-2'-oxospiro[cyclopropane-1,3'-indoline]-5'-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(58), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (61), 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(62), 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(66), 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(73), 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (74), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (75), 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(76), 5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2-oxoindoline-7-carbonitrile(77), (S)-5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (78), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one (85), and A PDE3 inhibitor selected from the group consisting of 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one (86) (Example #), its stereoisomers, and veterinary-acceptable salts thereof.

[0010] In another embodiment, 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(19), 7-Bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(23), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(24), 7-Chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one(25), 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (57), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (61), 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(62), 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(73), 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (74), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (75), 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (76), and A PDE3 inhibitor selected from the group consisting of 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one (86) (Example #), its stereoisomers, and veterinary-acceptable salts thereof.

[0011] In another embodiment, 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(19), 7-Bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(23), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(24), 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (57), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (61), 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(62), 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(73), 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (74), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (75), and A PDE3 inhibitor selected from the group consisting of 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (76) (Example #), its stereoisomers, and veterinary-acceptable salts thereof.

[0012] In another embodiment, 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(19), 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (57), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (61), 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (62), and A PDE3 inhibitor selected from the group consisting of 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (73) (Example #), its stereoisomers, and veterinary-acceptable salts thereof.

[0013] In another embodiment, 7-Bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(23), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(24), 7-Chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one(25), 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (74), 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (75), 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (76), and A PDE3 inhibitor selected from the group consisting of 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one (86) (Example #), its stereoisomers, and veterinary-acceptable salts thereof.

[0014] In another embodiment, 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(19), 7-Bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(23), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(24), 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (57), 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (62), and A PDE3 inhibitor selected from the group consisting of 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (75) (Example #), its stereoisomers, and veterinary-acceptable salts thereof.

[0015] In another embodiment, 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(19), 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (57), and 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(62), The PDE3 inhibitors selected from the group consisting of the following, their stereoisomers, and veterinary-acceptable salts thereof.

[0016] In another embodiment, 7-Bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one(23), 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (24), and A PDE3 inhibitor selected from the group consisting of 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (75) (Example #), its stereoisomers, and veterinary-acceptable salts thereof.

[0017] In another embodiment, the PDE3 inhibitor 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(19), its stereoisomers, and veterinary-acceptable salts thereof.

[0018] In another embodiment, the PDE3 inhibitor 7-bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (23), its stereoisomers, and veterinarily acceptable salts thereof.

[0019] In another embodiment, the PDE3 inhibitor 7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (24), its stereoisomers, and veterinarily acceptable salts thereof.

[0020] In another embodiment, the PDE3 inhibitor 7-chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one (25), its stereoisomers, and veterinarily acceptable salts thereof.

[0021] In another embodiment, the PDE3 inhibitor 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (57), its stereoisomers, and veterinarily acceptable salts thereof.

[0022] In another embodiment, PDE3 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (61), its stereoisomers, and veterinarily acceptable salts thereof.

[0023] In another embodiment, the PDE3 inhibitor 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (62), its stereoisomers, and veterinarily acceptable salts thereof.

[0024] In another embodiment, the PDE3 inhibitor 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (73), its stereoisomers, and veterinarily acceptable salts thereof.

[0025] In another embodiment, the PDE3 inhibitor 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (74), its stereoisomers, and veterinarily acceptable salts thereof.

[0026] In another embodiment, the PDE3 inhibitor 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (75), its stereoisomers, and veterinarily acceptable salts thereof.

[0027] In another embodiment, the PDE3 inhibitor 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (76), its stereoisomers, and veterinarily acceptable salts thereof.

[0028] In another embodiment, the PDE3 inhibitor 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one (86), its stereoisomers, and veterinarily acceptable salts thereof.

[0029] Another aspect of the present invention is a composition comprising a compound of the present invention selected from the group consisting of Examples #1, 2, 4, 6-9, 12-13, 17-19, 23-53, 55-59, 61-63, 66, 68, and 71-89, its stereoisomer, or a veterinarily acceptable salt thereof. Another aspect is a composition comprising a compound of the present invention selected from the group consisting of Examples #1, 6, 8, 12-13, 18-19, 23-28, 30-43, 56-59, 61-63, 66, 71, 73-80, 83, and 85-86, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises a compound of the present invention selected from the group consisting of Examples #12, 19, 23-28, 30-33, 56-58, 61-62, 66, 73-78, 85, and 86, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises a compound of the present invention selected from the group consisting of Examples #19, 23, 24, 57, 61-62, and 73-76, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises any one of the compounds selected from Examples #19, 57, 61, 62, and 73, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises a compound of the present invention selected from the group consisting of Examples #23, 24, 25, 74, 75, 76, and 86, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises a compound of the present invention selected from the group consisting of Examples #23, 24, 74, 75, and 76, its stereoisomer, or a veterinarily acceptable salt thereof. In yet another embodiment, the composition comprises a compound of the present invention selected from the group consisting of Examples #19, 57, and 62, its stereoisomer, or a veterinarily acceptable salt thereof. In yet another embodiment, the composition comprises a compound of the present invention selected from the group consisting of Examples #23, 24, and 75, its stereoisomer, or a veterinarily acceptable salt thereof. In yet another embodiment, the composition comprises Example #19, its stereoisomer, and a veterinarily acceptable salt thereof. In yet another embodiment, the composition comprises Example #23, its stereoisomer, and a veterinarily acceptable salt thereof.In another embodiment, the composition comprises Example #24, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises Example #25, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises Example #57, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises Example #61, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises Example #62, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises Example #73, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises Example #74, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises Example #75, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises Example #76, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, the composition comprises Example #86, its stereoisomers, and veterinarily acceptable salts thereof. In yet another embodiment, the composition comprises Example #86, its stereoisomers, or veterinarily acceptable salts thereof. In yet another embodiment, the composition further comprises at least one veterinarily acceptable excipient. In yet another embodiment, the composition further comprises at least one additional pharmaceutically acceptable agent. In yet another embodiment, the at least one additional pharmaceutically acceptable agent is selected from the group consisting of ACE inhibitors, furosemide, and spironolactone. In yet another embodiment, each of the compositions described herein may be in solid or liquid form. Preferably, the compositions described herein are in solid form that can be administered orally, for example, tablets or capsules. The oral composition may be a film-coated tablet or a flavored chewable tablet.

[0030] Another aspect of the present invention provides a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, by administering a therapeutic dose of a compound of the present invention selected from the group consisting of Examples #1, 2, 4, 6-9, 12-13, 17-19, 23-53, 55-59, 61-63, 66, 68, and 71-89, its stereoisomer, or a veterinarily acceptable salt thereof. Another aspect provides a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, by administering a therapeutic dose of a compound of the present invention selected from the group consisting of Examples #1, 6, 8, 12-13, 18-19, 23-28, 30-43, 56-59, 61-63, 66, 71, 73-80, 83, and 85-86, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of a compound of the present invention selected from the group consisting of Examples #12, 19, 23-28, 30-33, 56-58, 61-62, 66, 73-78, 85, and 86, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of a compound of the present invention selected from the group consisting of Examples #19, 23, 24, 57, 61-62, and 73-76, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, a method for treating an animal having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of a compound of the present invention, selected from the group consisting of Examples #19, 57, 61, 62, and 73, its stereoisomer, or a veterinarily acceptable salt thereof. In another embodiment, a method for treating an animal having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of a compound of the present invention, selected from the group consisting of Examples #23, 24, 25, 74, 75, 76, and 86, its stereoisomer, or a veterinarily acceptable salt thereof.In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of a compound of the present invention, its stereoisomer, or a veterinarily acceptable salt thereof, selected from the group consisting of Examples #23, 24, 74, 75, and 76. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of a compound of the present invention, its stereoisomer, or a veterinarily acceptable salt thereof, selected from the group consisting of Examples #19, 57, and 62. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of a compound of the present invention, its stereoisomer, or a veterinarily acceptable salt thereof, selected from the group consisting of Examples #23, 24, and 75. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of Example #19, its stereoisomer, and veterinarily acceptable salts thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of Example #23, its stereoisomer, and veterinarily acceptable salts thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of Example #24, its stereoisomer, and veterinarily acceptable salts thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of Example #25, its stereoisomer, and veterinarily acceptable salts thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure is a method by administering a certain therapeutic dose of Example #57, its stereoisomers, and veterinarily acceptable salts thereof.In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of Example #61, its stereoisomer, and veterinarily acceptable salts thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of Example #62, its stereoisomer, and veterinarily acceptable salts thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of Example #73, its stereoisomer, and veterinarily acceptable salts thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure, comprising administering a therapeutic dose of Example #74, its stereoisomer, and veterinarily acceptable salts thereof. In another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure is provided by administering a therapeutic dose of Example #75, its stereoisomer, and veterinarily acceptable salts thereof. In yet another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure is provided by administering a therapeutic dose of Example #76, its stereoisomer, and veterinarily acceptable salts thereof. In yet another embodiment, a method for treating animals having MMVD, CHF, and / or asymptomatic heart failure is provided by administering a therapeutic dose of Example #86, its stereoisomer, and veterinarily acceptable salts thereof. In yet another embodiment of treating animals having MMVD, CHF, and / or asymptomatic heart failure by administering a therapeutic dose of any one of the compounds of the present invention, the method involves co-administration of at least one additional pharmaceutical agent selected from the group consisting of ACE inhibitors, furosemide, and spironolactone.

[0031] Another aspect of the present invention involves the use of compounds of the present invention selected from the group consisting of Examples #1, 2, 4, 6-9, 12-13, 17-19, 23-53, 55-59, 61-63, 66, 68, and 71-89, their stereoisomers, or veterinarily acceptable salts thereof, for preparing pharmaceuticals for treating animals having MMVD, CHF, and / or asymptomatic heart failure. Another aspect involves the use of compounds of the present invention selected from the group consisting of Examples #1, 6, 8, 12-13, 18-19, 23-28, 30-43, 56-59, 61-63, 66, 71, 73-80, 83, and 85-86, their stereoisomers, or veterinarily acceptable salts thereof, for preparing pharmaceuticals for treating animals having MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of compounds of the present invention selected from the group consisting of Examples #12, 19, 23-28, 30-33, 56-58, 61-62, 66, 73-78, 85 and 86, their stereoisomers, or veterinarily acceptable salts thereof, for preparing pharmaceuticals for treating animals having MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of compounds of the present invention selected from the group consisting of Examples #19, 23, 24, 57, 61-62 and 73-76, their stereoisomers, or veterinarily acceptable salts thereof, for preparing pharmaceuticals for treating animals having MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of compounds of the present invention, selected from the group consisting of Examples #19, 57, 61, 62, and 73, their stereoisomers, or veterinarily acceptable salts thereof, for preparing pharmaceuticals for treating animals having MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of compounds of the present invention, selected from the group consisting of Examples #23, 24, 25, 74, 75, 76, and 86, their stereoisomers, or veterinarily acceptable salts thereof, for preparing pharmaceuticals for treating animals having MMVD, CHF, and / or asymptomatic heart failure.Another embodiment involves the use of compounds of the present invention, selected from the group consisting of Examples #23, 24, 74, 75, and 76, their stereoisomers, or veterinarily acceptable salts thereof, for preparing pharmaceuticals for treating animals having MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of compounds of the present invention, selected from the group consisting of Examples #19, 57, and 62, their stereoisomers, or veterinarily acceptable salts thereof, for preparing pharmaceuticals for treating animals having MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of compounds of the present invention, selected from the group consisting of Examples #23, 24, and 75, their stereoisomers, or veterinarily acceptable salts thereof, for preparing pharmaceuticals for treating animals having MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #19, its stereoisomers, or veterinarily acceptable salts thereof for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #23, its stereoisomers, or veterinarily acceptable salts thereof for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #24, its stereoisomers, or veterinarily acceptable salts thereof for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #25, its stereoisomers, or veterinarily acceptable salts thereof for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #57, its stereoisomers, or veterinarily acceptable salts thereof, for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #61, its stereoisomers, or veterinarily acceptable salts thereof, for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure.Another embodiment involves the use of Example #62, its stereoisomers, or veterinarily acceptable salts thereof, for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #73, its stereoisomers, or veterinarily acceptable salts thereof, for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #74, its stereoisomers, or veterinarily acceptable salts thereof, for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #75, its stereoisomers, or veterinarily acceptable salts thereof, for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #76, its stereoisomers, or veterinarily acceptable salts thereof for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Another embodiment involves the use of Example #86, its stereoisomers, or veterinarily acceptable salts thereof for preparing a pharmaceutical for treating animals with MMVD, CHF, and / or asymptomatic heart failure. Yet another embodiment involves the use of any one of the compounds of the present invention for preparing a pharmaceutical together with at least one other additional pharmaceutical agent selected from the group consisting of ACE inhibitors, furosemide, and spironolactone for treating animals with MMVD, CHF, and / or asymptomatic heart failure. [Modes for carrying out the invention]

[0032] definition For the purposes of the invention described herein and claimed herein, the following terms and phrases are defined as follows:

[0033] As used herein, “additional veterinary (or pharmaceutical) agent(s)” means, unless otherwise indicated, other veterinary or pharmaceutical compounds or products (i.e., drugs) that provide a therapeutically effective amount of such agent(s) useful for the treatment of MMVD, CHF, and / or asymptomatic heart failure in animals, preferably dogs.

[0034] As used herein, “animals” refers to individual mammals unless otherwise indicated. Specifically, mammals refer to vertebrates that are human or non-human and are taxonomically members of the class Mammalia. Non-exclusive examples of non-human mammals include companion animals. Non-exclusive examples of companion animals include cats (Felidae), dogs (Canidae), and horses (Equidae). The preferred companion animal is the dog.

[0035] As used herein, “asymptomatic (occult, preclinical) heart failure” means any contractile disorder or disease of the heart resulting from MMVD, unless otherwise indicated.

[0036] "The compound(s) of the present invention" refers, unless otherwise indicated or requested, to the PDE3 receptor antagonists (inhibitors) described herein as Examples #1 to #89, their stereoisomers, and / or veterinarily acceptable salts. The exemplary numbers of the compounds correspond synonymously to their specific exemplary names and structures.

[0037] As used herein, “comprises” or “comprising” will be understood to mean comprehensive, that is, including not only the enumerated components it directly refers to, but also other unspecified components or elements.

[0038] Congestive heart failure, or simply heart failure, unless otherwise specified, refers to the apparent process in which the heart is unable to keep up with the body's demands for blood supply, generally resulting in the accumulation of fluid in the lungs due to increased pressure in the heart and lungs. The term (plural) also refers to any contractile disorder or disease of the heart. Clinical symptoms are, in principle, the result of changes in the cellular and molecular components of the heart, as well as changes in the mediators that drive homeostatic control, leading to increased heart size and deterioration of cardiac function.

[0039] Myxomatous mitral valve disease (MMVD) refers to the apparent process of mitral valve degeneration unless otherwise specified. MMVD is commonly detected as a heart murmur by auscultation. MMVD also includes synonymous medical terms such as mitral valve disease (MVD), degenerative mitral valve disease (DMVD), chronic valve disease (CVD), chronic valvular heart disease (CVHD), and atrioventricular valve insufficiency (AVVI).

[0040] As used herein, “stereoisomers” specifically refers to the compounds of the present invention having at least one chiral carbon, existing as enantiomers (S and R optical isomers) that are mirror images of each other, chemically identical but incapable of superposition. A mixture of (S) and (R) enantiomers is racemic. For example, Examples #33 and #51 are the (R) and (S) isomers of Example #24 (racemic mixture), respectively.

[0041] Unless otherwise indicated, “therapeutic dose” means the amount of the compound of the present invention that (i) treats MMVD, CHF, and / or asymptomatic heart failure in animals; (ii) reduces, improves, or eliminates one or more symptoms of MMVD, CHF, and / or asymptomatic heart failure in animals; or (iii) prevents or delays the onset of MMVD, CHF, and / or asymptomatic heart failure in animals.

[0042] As used herein, “treating,” “treat,” etc., unless otherwise indicated, refer to mitigating, halting, or delaying the progression of MMVD, CHF, and / or asymptomatic heart failure in animals. As used herein, these terms also include, depending on the condition of the animal, preventing the onset of a disorder or condition, or symptoms associated with a disorder or condition, and reducing the severity of a disorder or condition or symptoms associated with it. Therefore, treatment may refer to the administration of the compounds of the present invention to animals that have not been diagnosed with CHF at the time of administration.

[0043] "Veterinarily acceptable" means, unless otherwise indicated, a substance or composition that is chemically and / or toxicologically compatible with the animal receiving the substance or composition. The term is also intended to mean "pharmaceutically acceptable" and is used interchangeably.

[0044] As described herein, “and veterinarily acceptable salts (plural)” also equally describes “or veterinarily acceptable salts (plural).” In some cases, the stereoisomers of this embodiment, the veterinarily acceptable salts of this embodiment, or their stereoisomers can be used in compositions or pharmaceuticals for the treatment of MMVD, CHF, and / or asymptomatic heart failure in animals.

[0045] Myxomatous mitral valve disease (MMVD) is the most common acquired heart disease in older dogs and is characterized by a new heart murmur. A heart murmur is a sound heard with every heartbeat and is caused by turbulent blood flow in the heart. MMVD is a symptom of a process that can affect the mitral valve. MMVD primarily affects older, smaller breed dogs, but can affect larger breed dogs as well. Some smaller breed dogs are affected earlier than others, with the Cavalier King Charles Spaniel being the most prominent example described so far.

[0046] The mitral valve is the valve between the left atrium and the left ventricle. Oxygenated blood from the lungs enters the left atrium, passes through the mitral valve to the left ventricle, and is then pumped to the body. The mitral valve closes when the left ventricle contracts, preventing blood from returning to the left atrium. A healthy mitral valve is thin, flexible, and held in place by chordae tendineae (CTs). Myxomatous degeneration is a process that occurs when the valve thickens due to the formation of small nodules, preventing complete closure of the valve and causing backflow of blood into the left atrium (mitral regurgitation). Over time, the atria and ventricles compensate by hypertrophying, and the leakage gradually worsens. As the amount of leakage increases, atrial pressure rises. In some cases, the CTs rupture, leaving the mitral valve partially unfixed (mitral valve prolapse). The increased pressure is transmitted to the lungs, resulting in CHF (congenital heart failure).

[0047] A heart murmur is generally the earliest means of detecting MMVD. After a murmur is detected, MMVD symptoms may not appear for 3-4 years. Often, the first external sign of MMVD exacerbation is a cough or increased breathing effort, which may be due to airway pressure from an enlarged heart, as well as / or fluid congestion in the lungs, pericardium, and heart.

[0048] Current medications can slow the progression from MMVD to CHF, particularly in the early stages of the disease. Treatment includes, but is not limited to, furosemide, pimobendan, ACE inhibitors (e.g., enalapril), and spironolactone, and is administered to manage MMVD, CHF, and / or asymptomatic heart failure. Furosemide is a potent diuretic that removes fluid from the body, thereby reducing pulmonary fluid congestion. Pimobendan has been shown to help the heart function more effectively, reduce cardiac remodeling, and improve survival rates in MMVD patients. ACE inhibitors and spironolactone have also been shown to block harmful compensatory mechanisms that occur in severe heart disease, thereby extending survival. Side effects of these medications include allergic reactions, dizziness, loss of appetite, lethargy, diarrhea, and syncope. Other medications that can be used to manage the symptoms of CHF include hydrochlorothiazide, amlodipine, torsemide, and digoxin.

[0049] Despite the development of new drugs and treatment regimens, uncertainty remains regarding when to treat and what the best intervention is for some of these animals. In 2009, an objective classification system for classifying heart disease based on risk factors as well as clinical and diagnostic imaging signs was developed.

[0050] Heart failure is divided into different stages, which are defined by different classification systems, such as the International Small Animal Cardiac Health Council (ISACHC), the New York Heart Association (NYHA) functional classification system, and the classification currently in use according to the American College of Veterinary Internal Medicine (ACVIM) consensus statement (2009). To eliminate any ambiguity between classification systems, the classification systems described below are considered synonymous.

[0051] Classification by the International Small Animal Cardiac Health Council (ISACHC) system: Class I: Asymptomatic (also known as occult or preclinical), Class IA: No evidence of compensation for underlying heart disease (no volumetric or pressure overload detected on radiography or echocardiography), Class IB: Clinical signs of compensation for underlying heart disease (volumetric or pressure overload detected on radiography or echocardiography), Class II: Mild to moderate heart failure with clinical signs at rest or during light exercise (requires treatment), Class III: Advanced heart failure, clinical signs of severe congestive heart failure, Class IIIA: Can be treated at home, Class IIIB: Requires hospitalization.

[0052] The New York Heart Association (NYHA) functional classification system: Class I: Represents patients with asymptomatic heart disease (e.g., chronic valvular heart disease (CVHD) is present, but clinical signs are not evident even with exercise); Class II: Represents patients with heart disease that presents clinical signs only during strenuous exercise; Class III: Represents patients with heart disease that presents clinical signs with everyday activities or light exercise; Class IV: Represents patients with heart disease that presents severe clinical signs even at rest.

[0053] The ACVIM system describes four basic stages of heart disease and heart failure. Stage A: Patients at high risk of developing heart disease but without currently identifiable structural cardiac impairment; Stage B: Patients with structural heart disease (e.g., presence of a typical murmur of mitral regurgitation) but without clinical signs of heart failure (for significant clinical implications for prognosis and treatment, the panel further subdivided Stage B into Stages B1 and B2). Stage B1: Asymptomatic patients with no radiographic or echocardiographic evidence of cardiac remodeling in response to CVHD. Stage B2: Asymptomatic patients with hemodynamically significant valvular regurgitation as evidenced by radiographic or echocardiographic findings of left cardiomegaly; Stage C: Patients with past or present clinical signs of heart failure associated with structural heart disease; Stage D: Patients with end-stage disease who are resistant to standard therapy and have clinical signs of heart failure caused by CVHD.

[0054] Cardiac pathology begins with ISACHC class I, NYHA class I, and ACVIM stage B2, where there is a heart murmur or ventricular hypertrophy, but no clinical symptoms (ISACHC class I or asymptomatic / occult / preclinical stage). Clinical symptoms become apparent as the disease progresses (ISACHC class II or III, NYHA class II, III, or IV, ACVIM stages C and D).

[0055] The compounds of the present invention have affinity for PDE3 and may provide veterinarians with novel potential drugs for treating MMVD, CHF, and / or asymptomatic heart failure in animals.

[0056] The compounds of the present invention are useful as PDE3 antagonists for the treatment of MMVP, CHF, and / or asymptomatic heart failure in animals, particularly dogs. Another aspect of the present invention is a veterinary composition comprising a therapeutically effective amount of the compound of the present invention and a veterinarily acceptable salt thereof. Another aspect of the present invention is a veterinary composition comprising a therapeutically effective amount of the compound of the present invention, a veterinarily acceptable salt thereof, and a veterinarily acceptable excipient. The compounds of the present invention (including the compositions and processes used therein) may also be used in the manufacture of pharmaceuticals for the therapeutic uses described herein.

[0057] The compounds of the present invention can be administered alone or in formulations appropriate to the specific use and treatment of the animal species. Generally, they will be administered as formulations in conjunction with one or more veterinarily acceptable excipients. The term “excipient” is used herein to describe any component other than the compounds of the present invention, their salts, or any additional veterinary agents. The choice of excipients will depend largely on factors such as the specific mode of administration, the effect of the excipients on solubility and stability, and the nature of the dosage form. In addition to excipients, the amount of the compounds of the present invention administered, and the dosage regimen for treating a condition or disorder with the compounds, may vary considerably, as they depend on a variety of factors including the animal’s age, weight, sex, and medical condition, the severity of the disease, the route and frequency of administration.

[0058] In one embodiment, the veterinary composition comprises the compound of the present invention together with veterinary-acceptable excipients. The concentration range will vary depending on the composition (e.g., orally or injectably administered). The range of the activator (i.e., the compound of the present invention (e.g., Examples #19, #23, #24, #57, #62, #75, etc.) is about 0.005 to 10 mg / kg, or about 0.01 to 10 mg / kg, or about 0.1 to 10 mg / kg, or about 0.1 to 5 mg / kg, or about 0.2 to 5 mg / kg, or about 0.2 to about 2.5 mg / kg). The preferred route of administration is orally. The concentration range and preferred concentration range are considered to be therapeutically effective doses. Furthermore, the dose range and preferred dose range may be higher or lower than the concentrations described herein.

[0059] The formulations can be prepared using conventional dissolution and mixing procedures. Such compositions and methods for their preparation can be found, for example, in “Remington's Veterinary Sciences”, 19th Edition (Mack Publishing Company, 1995) and “Veterinary Dosage Forms: Tablets, Vol. 1”, by H. Lieberman and L. Lachman, Marcel Dekker, NY, 1980 (ISBN 0-8247-6918-X).

[0060] A typical formulation is prepared by mixing the compound of the present invention with at least one veterinarily acceptable excipient. Suitable excipients are well known to those skilled in the art and include materials such as carbohydrates, waxes, water-soluble and / or swelling polymers, hydrophilic or hydrophobic materials, gelatin, oils, solvents, and water. The specific excipient(s) will depend on the means and purpose to which the compound of the present invention is applied. The solvent is generally selected based on a solvent that is recognized to those skilled in the art as safe for administration to animals. The formulation may also include one or more buffers, stabilizers, surfactants, wetting agents, lubricants, emulsifiers, suspending agents, preservatives, antioxidants, opacifiers, lubricants, processing aids, colorants, sweeteners, fragrances, flavorings, and other known additives to provide a refined appearance for the drug (i.e., the compound of the present invention or its veterinary composition) or to assist in the manufacture of a veterinary product (i.e., a pharmaceutical). The compounds of the present invention will typically be formulated into veterinary dosage forms to provide dosage forms that are easily controllable for administration.

[0061] Methods for administering the compounds of the present invention include oral and injectable methods (e.g., parenteral and subcutaneous).

[0062] The compounds of the present invention can be administered orally in the form of capsules, boluses, tablets, powders, lozenges, chewable tablets, multi- and nanoparticles, gels, solid solutions, films, sprays, or liquids. This is a preferred method of administration, and therefore, it is desirable to develop compounds for oral administration. Such formulations may include soft or hard capsules and tablets, soft or hard chewable tablets with a pleasant mouthfeel, and may typically include excipients, such as water, ethanol, polyethylene glycol, N-methylpyrrolidone, propylene glycol, methylcellulose, glycerol, magnesium stearate, pregelled starch, sodium starch glycolate, animal-based flavorings (e.g., chicken, liver, beef), non-animal-based flavorings (e.g., vegetables, fruits, yeast), as well as other known pharmaceutical excipients designated as fillers, disintegrants, stabilizers, antioxidants, preservatives, etc. Liquid forms include suspensions, solutions, syrups, liquid medicines, and elixirs. Liquid formulations can be prepared, for example, by reconstituting a solid from a sachet or lyophilized material.

[0063] The formulations for injection may be prepared in the form of sterile aqueous solutions that may contain other substances, such as sufficient salts or glucose to make the solution isotonic with blood. Acceptable liquid excipients include vegetable oils such as sesame oil and cottonseed oil, glycers such as triacetin, esters such as benzyl benzoate, isopropyl myristate, and fatty acid derivatives of propylene glycol, and organic solvents such as pyrrolidine-2-one, benzyl alcohol, and glycerol formal. The formulations are prepared by dissolving or suspending the compounds of the present invention, alone or together with additional veterinary agents, in liquid excipients(s) such that the final formulation contains about 0.01 to 30% by weight of the active ingredient.

[0064] Suitable devices for injectable administration include needle syringes (including microneedles), needleless syringes, and injection techniques. Injectable formulations are typically aqueous solutions that may contain salts, carbohydrates, and excipients such as buffers (preferably up to pH 3–9), but for some applications, they may be more preferably formulated as sterile non-aqueous solutions or as dry powders used with a suitable vehicle such as sterile pyrogen-free water. For example, the preparation of injectable formulations under sterile conditions by lyophilization can be easily achieved by standard veterinary techniques well known to those skilled in the art. The solubility of the compounds of the present invention used in the preparation of injectable solutions may be increased by using appropriate formulation techniques, such as incorporating solubility enhancers.

[0065] The compounds of the present invention are intended to be administered once or twice daily, preferably once daily. Furthermore, the compounds of the present invention may also be administered once or twice every 2, 3, 4, 5, 6, or 7 days.

[0066] The compositions of the present invention may provide broader veterinary utility when administered alone or in combination with at least one other additional veterinary agent, as described herein. These at least one other additional veterinary agent, including pharmaceutical agents, may be administered simultaneously with the compounds of the present invention or at any time during the treatment period of the animal.

[0067] The following list of additional pharmacognostic (veterinary) cardiovascular agents that may be used in conjunction with the compounds of the present invention to treat heart disease (e.g., MMVD, CHF, and / or asymptomatic heart failure) in animals is intended to illustrate possible combinations and not to impose any limitations thereon. Non-limiting examples of additional pharmacognostic (veterinary) agents include diuretics to reduce edema and exudation (e.g., furosemide, chlorothiazide, indapamide, triamterene, hydrochlorothiazide, etc.); aldosterone antagonists to reduce aldosterone-mediated cardiomyopathy (e.g., spironolactone, eplerenone, etc.), which may slow the progression of heart disease and block sodium reabsorption that promotes water loss; and ACE inhibitors to inhibit the action of angiotensin-converting enzyme (e.g., enalapril, ramipril, benazepril, imidapril, etc.), which result in balanced vasodilation by relaxing blood vessels.

[0068] Veterinary compositions for application to animals may be packaged in various ways depending on the method used to administer the compounds or combinations of the present invention. Generally, the articles for distribution include a container in which the veterinary composition is deposited in an appropriate form. Suitable containers are well known to those skilled in the art and include materials such as bottles (plastic and glass), pouches, ampoules, plastic bags, and metal cylinders. The container may also include a tamper-evident assembly to prevent accidental access to the contents of the package. Furthermore, the container may have a label attached thereto that describes the contents of the container. The label may also include appropriate warnings.

[0069] The compounds of the present invention (including the compositions and processes used therein) may also be used in the manufacture of pharmaceuticals for therapeutic uses as described herein.

[0070] The structures of the compounds in the following examples were confirmed by one or more methods: proton magnetic resonance spectroscopy and / or mass spectrometry. Proton magnetic resonance (1H NMR) spectra were determined using a Bruker spectrometer operated at a magnetic field strength of 400 megahertz (MHz). Chemical shifts were reported in parts per million (PPM, δ) at low magnetic fields from an internal tetramethylsilane standard or a residual protonated NMR solvent. Mass spectral (MS) data can be obtained using an Agilent 6125 or 6140 single quadrupole mass spectrometer and an Agilent 1200 series LC / MS system with a Waters BEH C8 1.7 μm 2.1 × 50 mm column under gradient conditions of 0.1% TFA in acetonitrile / water, or similar instrumentation (Waters Acquity or Shimadzu), column (Waters Acquity BEH C8 column, Waters YMC Triart C18, Waters Xbridge C18 / Agilent Zorbax C18 or Waters Xbridge). It was obtained using C18) and using mobile phase gradient conditions (A: 0.05% formic acid in water, B: ACN: 0.05% formic acid in water (90:10), or A: 10 mM ammonium acetate in water, B: ACN, or A: 5 mM ammonium acetate in water, B: ACN: 5 mM ammonium acetate in water (90:10), or A: 0.1% formic acid in water, B: 0.1% formic acid in ACN).

[0071] The compounds of the present invention can be synthesized by synthetic routes involving processes similar to those well known in the field of chemistry, particularly in light of the description contained herein. Starting materials are generally available from commercial suppliers such as Aldrich Chemicals (Milwaukee, Wis.) or can be readily prepared using methods well known to those skilled in the art (e.g., by methods generally described in Louis F. Fieser and Mary Fieser, “Reagents for Organic Synthesis”, 1;19, Wiley, New York (1967, 1999 ed.), or Beilsteins Handbuch der organischen Chemie, 4, Aufl. ed. Springer-Verlag, Berlin (including supplements) (also available from the Beilstein online database)). For illustrative purposes, the following reaction schemes illustrate possible routes for synthesizing the compounds and key intermediates of the present invention. Further detailed descriptions of individual reaction steps can be found in the Examples section. Those skilled in the art will understand that the compounds of the present invention can be prepared by means other than those described herein, by adaptation of the methods described herein and / or by adaptation of the art known in the art described herein, for example, by using standard texts such as "Comprehensive Organic Transformations - A Guide to Functional Group Transformations", RC Larock, Wiley-VCH (1999 or later edition).

[0072] Many of the compounds of the present invention described herein contain at least one asymmetric or chiral center and therefore exist in different stereoisomer forms. Chirality refers to a structural feature of a molecule that prevents it from being superimposed onto its mirror image (e.g., "R" and "S" enantiomers). Examples 7, 9, 15, 25, 27, 32, 44, 52, 59, 61, 66, 72, 84-86, and 88-89 do not contain a chiral carbon. The R and S configurations are based on known chiral inversion / retention chemistry knowledge. Unless otherwise specified, the stereoisomer forms of the compounds of the present invention and their racemic mixtures are intended to form part of the present invention. Racemic mixtures of enantiomers can be separated into their individual enantiomer forms by methods well known to those skilled in the art, such as chromatography and / or fractional crystallization, based on their physicochemical differences. A more detailed description of the techniques that can be used to separate stereoisomers of compounds from their racemic mixtures can be found in Jean Jacques Andre Collet, Samuel H. Wilen, Enantiomers, Racemates and Resolutions, John Wiley and Sons, Inc. (1981). Those skilled in the art will understand that if one stereoisomer is more active and / or enriched with other stereoisomeric forms, then separation from a racemic mixture may have beneficial effects.

[0073] Examples and general procedures useful for the preparation and isolation of the compounds of the present invention are described herein. However, it should be understood that the present invention, as fully described herein and as defined in the claims, is not intended to be limited by the following schemes or preparation details.

[0074] In the schemes and examples described herein, the following reactants and other abbreviations refer to acetic acid (AcOH), acetonitrile (Acn or MeCN), aluminum chloride (AlCl3), carbonyl diimidazole (CDI), dichloromethane (DCM, CH2Cl2), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), 1,1'-bis(diphenylphosphin)ferrocene (dppf), ethyl acetate (RINKAN), ethanol (EtOH), ethylmagnesium bromide (EtMgBr), [dimethylamino(triazolo[4,5-b]pyridine-3-yloxy)methylidene]-dimethyl-azanium hexafluorophosphate (HATU), hydrochloric acid (HCl), high-pressure liquid chromatography (HPLC), isopropylmagnesium chloride / lithium chloride (iPrMgCl2).LiCl), potassium carbonate (K2CO3), potassium tripodium phosphate (K3PO4), potassium bis(trimethylsilyl)amide (KHMDS), potassium acetate (KOAc), potassium thiocyanate (KSCN), lithium boro (LiBH4), liquid chromatography-mass spectrometry (LCMS), lithium bis(trimethylsilyl)amide (LiHMDS), lithium hydroxide (LiOH), methanol (MeOH), 2-methyltetrahydrofuran (MeTHF), sodium carbonate (Na2CO3) Sodium bicarbonate (NaHCO3), sodium nitrite (NaNO2), sodium sulfate (Na2SO4), N-bromosuccinimide (NBS), n-butyllithium (n-Buli), N-chlorosuccinimide (NCS), hydrazine (NH2NH2), nuclear magnetic resonance (NMR), N,N-disopropylethylamine (DIPEA), p-methoxybenzyl (PMB), room temperature (RT), triethylamine (TEA), trifluoroacetic acid (TFA), tetrahydrofuran (THF), thin-layer chromatography Phi (TLC), palladium (Pd), palladium on carbon (Pd / C), [1,1'-bis(diphenylphosphino)ferrocene]-dichloropalladium(II) (Pd(dppf)Cl2), tris(dibenzylideneacetone)dipalladium(O) (Pd2(dba)3), [1,1'-bis(di-tert-butylphosphino)-ferrocene]dichloropalladium(II) (Pd-118, Pd(dtbpf)Cl2), [1,1'-bis(diphenylphosphino)ferrocene]-dichloropalladium It contains a complex with palladium(II) dichloromethane (1:1; PD(dppf)Cl2.DCM), tert-butyl potassium oxide (t-BuOK), tri-tert-butylphosphine (P(tBu)3), water (H2O), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl[2-(2'-amino-1,1'-biphenyl)]palladium(II) methanesulfonate (XPhos Pd G3), and zinc cyanide (Zn(CN2)).

[0075] Veterinary-acceptable salts of the compounds of the present invention can also be prepared in a conventional manner. For example, a solution of the free base may be treated with a suitable acid in either a pure or suitable solvent, and the resulting salt is isolated by filtration of the reaction solvent or evaporation under reduced pressure. A general overview of suitable salts can be found in “Handbook of Pharmaceutical Salts: Properties, Selection, and Use” by Stahl and Wermuth (Wiley-VCH, Weinheim, Germany, 2002).

[0076] The compounds of the present invention may be used in their natural form or as salts. When the formation of stable, non-toxic acids or base salts is desired, administration of the compounds as veterinarily acceptable salts may be appropriate. Veterinarily acceptable salts of the compounds of the present invention include acetate, ascorbate, aspartate, benzoate, besylate, bicarbonate / carbonate, bisulfate / sulfate, borate, cansylate, citrate, edisylate, etoglutarate, esylate, formate, fumarate, gluceptate, gluconate, glucuronate, glucerophosphate, hexafluorophosphate, hibenzate, hydrochloride / chloride, Examples include, but are not limited to, hydrobromide / bromide, hydroiodine / iodine, isethionate, lactate, maleate, maleate, malonate, mesylate, methyl sulfate, naphthylate, 2-napsylate, nicotinate, nitrate, orotate, oxalate, palmitate, pamoate, phosphate / hydrogen phosphate / dihydrogen phosphate, saccharate, stearate, succinate, tartrate, tosylate, and trifluoroacetate salts.

[0077] For illustrative purposes, the reaction scheme below illustrates a possible route for synthesizing the compounds of the present invention. Those skilled in the art will understand that other suitable starting materials, reagents, and synthesis routes may be used to prepare the intermediates and compounds of the present invention. [Examples]

[0078] The following examples provide a more detailed description of each compound and process condition for preparing the compounds of the present invention. However, it should be understood that the present invention, as fully described herein and referenced in the claims, is not intended to be limited by the details of the preparation methods described below.

[0079] Examples #35 and #40 exist as tautomers in equilibrium, where the hydrogen atoms and double bonds of the quinolinyl ring spontaneously interconvert.

[0080] Preparation of Example #3 (8-bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one) and Example #12 (8-(3-fluorophenyl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one) [ka] Step 1: To a solution of 3,4-dihydroquinoline-2(1H)-one (2.5 g, 17 mmol) in 1,2-dichloroethane (25 mL), 2-chloropropanoyl chloride (4.25 g, 34 mmol, 2 equivalents) was added, followed by the addition of aluminum trichloride (9 g, 68 mmol, 4 equivalents) over 10 minutes with stirring in three equal parts. The mixture was then heated to 50°C in an inert atmosphere of nitrogen. After 3.5 hours, the reaction was deemed complete based on LC-MS analysis. The reaction mixture was poured directly into a beaker of ice. After the ice melted, the mixture was poured into a separatory funnel. Methylene chloride (100 mL) was added to extract the product. The organic phase was washed again with saturated NaHCO3 aqueous solution (1 × 50 mL) and brine (1 × 50 mL). The organic layer was dried and concentrated to obtain 6-(2-chloropropanoyl)-3,4-dihydroquinoline-2(1H)-one (2.75 g, 11.6 mmol), which was used directly in the next step.

[0081] Step 2: Potassium tert-butoxide (1.7 g, 15.1 mmol) was added to a stirred solution of DMSO (40 mL) in three equal portions over 20 minutes. The mixture was stirred for another 20 minutes. A solution of diethyl malonate (2.4 g, 15.1 mmol) in DMSO (5 mL) was added dropwise over 10 minutes. After stirring the solution for 20 minutes, 6-(2-chloropropanoyl)-3,4-dihydroquinoline-2(1H)-one (2.75 g, 11.6 mmol) was added as a solution in DMSO (10 mL). The reaction mixture was then warmed to 35°C and stirred for 3 hours. The mixture was cooled to room temperature and acetic acid (1.2 g, 20 mmol) was added. The mixture was then partitioned between ethyl acetate (150 mL) and water (100 mL). The organic layer was washed with water (4 × 70 mL). The organic layer was dried and concentrated to obtain crude diethyl 2-(1-oxo-1-(2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)propan-2-yl)malonate (3.5 g, 9.7 mmol).

[0082] Step 3: Diethyl 2-(1-oxo-1-(2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)propan-2-yl)malonate (3.5 g, 9.7 mmol) was mixed with 6N HCl (100 mL) and dioxane (20 mL). The reaction mixture was then heated at 90°C for 16 hours. The reaction mixture was poured into a beaker of ice water. Once the ice had melted, the mixture was poured into a separatory funnel, and the product was extracted using methylene chloride (4 × 50 mL). The combined organic washes were dried over sodium sulfate and concentrated to obtain crude 3-methyl-4-oxo-4-(2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)butanoic acid (1.8 g, 6.9 mmol).

[0083] Step 4: Ethanol (30 mL) was added to 3-methyl-4-oxo-4-(2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)butanoic acid (1.8 g, 6.9 mmol), followed by the addition of hydrazine monohydrate (1.75 g, 35 mmol). The solution was heated to 65°C for 4 hours. The mixture was poured into ice water (200 mL) to form a beige precipitate. The precipitate was collected using suction filtration and dried to obtain the product 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one (1.35 g, 5.2 mmol).

[0084] Step 5: To a solution of 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one (1.35 g, 5.2 mmol) in DMF (20 mL), NBS (1.1 g, 6.2 mmol) was added. The mixture was stirred at 55°C for 10 hours. The second portion of NBS (0.55 g, 3.1 mmol) was added while stirring at 55°C for a further 3 hours. The reaction mixture was then poured into ice water (150 mL). The beige precipitate was collected by suction filtration and washed with water (3 × 50 mL). Upon drying, the crude product 8-bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one (Example #3, 1.45 g, 4.3 mmol) was obtained. The pure product was obtained by flash column chromatography (3.5% MeOH in CH2Cl2). 1H NMR (400 MHz, DMSO-d6): δ 10.97 (s,1H), 9.31 (s,1H), 7.82 (d,1H), 7.65 (d,1H), 3.34-3.45 (m,1H), 2.98 (t,2H), 2.67 (dd,1H), 2.52-2.55 (m,2H), 2.18-2.28 (m,1H), 1.05 (d,3H).

[0085] Step 6: Dioxane (4 mL) and water (0.5 mL) were added to 8-bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one (120 mg, 0.36 mmol). Next, (3-fluorophenyl)boronic acid (80 mg, 0.57 mmol) and sodium bicarbonate (165 mg, 1.9 mmol) were added. The mixture was then degassed by several vacuum purges and refilled with nitrogen. Finally, 1,1-bis(diphenylphosphino)-ferrocene]dichloropalladium(II) (60 mg, 0.06 mmol) was added. The mixture was then heated at 75°C for 3 hours. The reaction product was filtered through a Celite plug. The plug was washed with methylene chloride (20 mL). The organic phase was washed with water (1 × 10 mL). The organic phase was concentrated. The crude residue was dissolved in DMF (4.5 mL), purified using reverse-phase HPLC, and lyophilized to obtain the compound of Example #12 (68 mg, 0.18 mmol). ¹H NMR (400 MHz, DMSO-d6): δ 10.92 (s, ¹H), 9.03 (s, ¹H), 7.68 (s, ¹H), 7.54-7.48 (m, ²H), 7.27-7.23 (m, ³H), 3.44-3.40 (m, ¹H), 2.99-2.96 (m, ²H), 2.68-2.62 (m, ¹H), 2.55-2.50 (m, ²H), 2.39-2.19 (m, ¹H), 1.06 (d, J = 7.2 Hz, ³H). LCMS: retention time = 2.51 min, HPLC purity = 98.20%

[0086] In Example #1, the preparation of 8-(2-methoxypyridine-4-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one was carried out in the same manner as in Example #12, but in step 6, (2-methoxypyridine-4-yl)boronic acid was used instead of (3-fluorophenyl)boronic acid to obtain the compound of Example #1. 1H NMR (400MHz, DMSO-d6): δ10.92(s,1H),9.23(s,1H),8.24(d,1H),7.83-7.60(m,1H),7.01(dd,1H),7.49(d,1H),4.39(br s,1H),6.85(s,1H),3.90(s,3H),3.43-3.22(m,1H),2.98(br t,2H),2.66(dd,1H),2.58-2.52(m,1H),2.22(d,1H),1.06(d,3H).

[0087] In Example #2, the preparation of 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-8-(thiazole-2-yl)-3,4-dihydroquinoline-2(1H)-one was carried out in the same manner as in Example #12, but in step 6, thiazole-2-ylboronic acid was used instead of (3-fluorophenyl)boronic acid to obtain the compound of Example #2. 1H NMR(400MHz,DMSO-d6):δ11.12(s,1H),10.95(s,1H),9.43(d,1H),8.42(d,1H),8.13-7.93(m,1H) ,7.72-7.67(m,1H),3.66-3.39(br,m,1H),3.03(t,2H),2.70(dd,1H),2.61-2.52(m,1H),1.30(br d,1H),1.09(d,3H).

[0088] In Example #4, the preparation of 8-(2-methoxythiazole-5-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one was carried out in the same manner as in Example #12, but in step 6, 2-methoxythiazole-5-ylboronic acid was used instead of (3-fluorophenyl)boronic acid to obtain the compound of Example #4. 1H NMR (400MHz, DMSO-d6): δ10.93(s,1H),9.38(s,1H),7.82-7.61(m,1H),7.55(d,1H),7.26(s,1H),4.07(s, 3H),3.57-3.37(m,2H),3.07-2.85(m,2H),2.80-2.59(m,1H),2.58-2.52(m,1H),2.23(d,1H),1.06(d,3H).

[0089] In Example #13, 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-8-(pyridine-3-yl)-3,4-dihydroquinoline-2(1H)-one was prepared in the same manner as in Example #12, except that in step 6, 3-pyridinylboronic acid was used instead of (3-fluorophenyl)boronic acid to obtain the compound of Example #13. 1H NMR (400 MHz, DMSO-d6): δ 10.91 (s, 1H). 9.34(s,1H),8.64-8.53(m,2H),7.90-7.75(m,1H),7.74-7.61(m,1H),7.60-7.36(m,2H),3.66- 3.39(m,2H),3.17-2.90(m,2H),2.82-2.60(m,1H),2.56-2.51(m,1H),2.22(d,1H),1.07(d,3H).

[0090] In Example #17, the preparation of 3,3-dimethyl-5-(4-methyl-6-oxo-1,6-dihydropyridazin-3-yl)-7-(thiazole-4-yl)indolin-2-one was carried out in the same manner as in Example #12, step 6, but thiophene-4-boronic acid was used instead of (3-fluorophenyl)boronic acid, and Example 47 was used instead of 8-bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinolin-2(1H)-one to obtain the compound of Example #17. 1H NMR (400MHz, DMSO-d6): δ10.91(s,1H),10.12(s,1H),9.29(s,1H),8.35(s,1H),8.09(s,1H),7.78( s,1H),3.57-3.54(m,1H),2.74-2.68(m,1H),2.32-2.24(m,1H),1.34(s,6H),1.10(d,J=7.2Hz,3H).

[0091] In Example #18, the preparation of 9-(6-methoxypyridine-3-yl)-7-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1,3,4,5-tetrahydro-2H-benzo[b]azepine-2-one was carried out in the same manner as in step 6 of Example #12, but (2-methoxypyridine-5-yl)boronic acid and 9-bromo-7-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1,3,4,5-tetrahydro-2H-benzo[b]azepine-2-one were used to obtain the compound of Example #18. ¹H NMR (400 MHz, DMSO-d6): δ8.96 (s, ¹H). 8.21-8.14(d,1H),7.76-7.70(m,2H),7.61-7.56(d,1H),6.94-6.87(d,1H),3.92-3.87(s,3H),3.50-3.42(m,1H),3.05-3.00( m,1H),2.81-2.74(br,t,2H),2.73-2.64(dd,1H),2.30-2.24(m,2H),2.19-2.10(m,2H),1.76-1.71(m,1H),1.07-1.11(d,3H).

[0092] In Example #63, the preparation of 6-methyl-5-(7-(4-(methylsulfonyl)phenyl)-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was carried out in the same manner as in Example #12, but in step 6, (4-(methylsulfonyl)phenyl)boronic acid was used instead of (3-fluorophenyl)boronic acid, and 5-(7-bromo-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was used instead of 8-bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one to obtain the compound of Example #63. 1H NMR(400MHz,DMSO-d6):δ11.62(s,1H),10.63(brs,1H),8.01(d,J=8.0Hz,2H),7.79-7.77 (m,3H),7.66(s,1H),4.85-4.80(m,1H),3.64(s,2H),3.26(s,3H),1.48(d,J=7.2Hz,3H).

[0093] In Example #68, the preparation of 5-(3,3-dimethyl-2-oxo-7-(thiazole-4-yl)indoline-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was carried out in the same manner as in Example #12, but in step 6, 4-thiazole-boronic acid was used instead of (3-fluorophenyl)boronic acid, and the compound of Example #76 was used instead of 8-bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one to obtain the compound of Example #68. 1H NMR(400MHz,DMSO-d6):δ11.65(s,1H),10.17(s,1H),9.30(d,J=1.8Hz,1H),8.36(d,J=1.8Hz,1H), 8.14(d,J=1.6Hz,1H),7.80(d,J=1.6Hz,1H),4.92-4.82(m,1H),1.51(d,J=7.2Hz,3H),1.35(s,6H).

[0094] In Example #71, the preparation of 5-(7-(4-chlorophenyl)-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was carried out in the same manner as in Example #12, but in step 6, 4-chlorophenyl-boronic acid was used instead of (3-fluorophenyl)boronic acid, and 5-(7-bromo-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was used instead of 8-bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one to obtain the compound of Example #71. 1H NMR (400MHz, DMSO-d6): δ11.59(s,1H),10.53(s,1H),7.71(s,1H),7.60(s,1H),7.52(s,4H),4.83-4.78(m,1H),3.62(s,2H),1.47(d,J=7.2Hz,3H).

[0095] The preparation of 7-chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one was prepared according to the following steps: [ka] Step 1: A slurry of AlCl3 (7.9 g, 59.39 mmol) and DMF (1.4 ml, 18.02 mmol) was heated at 70°C for 15 minutes, then cooled to 40°C. 7-Chloro-2,3-dihydro-1H-indole-2-one (1.0 g, 5.98 mmol) and 3-methyloxolan-2,5-dione (886 mg, 7.78 mmol) were slowly added. The resulting mixture was heated at 70°C for 1 hour, poured into ice-cold water, and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was pulverized with diethyl etherpentane to obtain 4-(7-chloro-2-oxoindolin-5-yl)-3-methyl-4-oxobutanoic acid (800 mg, 47%) as a brown gum. The process proceeded to the next step without further purification. MS(ESI):m / z 282.0[M+1]+.

[0096] Step 2: To a stirred solution of 4-(7-chloro-2-oxoindolin-5-yl)-3-methyl-4-oxobutanoic acid (400.0 mg, 1.42 mmol) in ethanol (20.0 mL), hydrazine monohydrate (0.27 ml, 5.69 mmol) was added. The resulting mixture was heated at 80°C for 16 hours. Crude LC-MS showed the formation of two peaks with product mass (undesirable:desirable = 4:1). The reaction mixture was evaporated under reduced pressure, the residue was incorporated into EtOH, and stirred under cooling. The solid thus formed was filtered and discarded [containing the undesirable major isomer]. The filtrate was concentrated under reduced pressure, and the crude mass was purified by combiflash column chromatography (60-70% siRNA in hexane), followed by reverse-phase preparative HPLC, to obtain the compound of Example 6 (40 mg, 10%) as an off-white solid. 1H NMR(400MHz,DMSO-d6):δ10.95(s,1H),10.92(s,1H),7.62-760(m,2H),3.64(s,2H ),3.38-3.34(m,1H),2.69-2.63(m,1H),2.22(d,J=16Hz,1H),1.04(d,J=8Hz,3H).

[0097] The preparation of Example #44 (7-chloro-3,3-dimethyl-5-(6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one) was carried out in the same manner as in Example #6, but 7-chloro-2,3-dimethyl-1H-indole-2-one was used instead of 7-chloro-2,3-dihydro-1H-indole-2-one, and succinic anhydride was used instead of 3-methyloxolan-2,5-dione to obtain the compound of Example #44. 1H NMR (400MHz, DMSO-d6): δ 10.94 (s,1H), 10.87 (s,1H), 7.68 (s,1H), 7.60 (s,1H), 2.93 (t,2H), 2.43 (t,2H), 1.30 (s,6H).

[0098] Preparation of Example #39 (7-chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2,3-dihydro-1H-isoindole-1-one) [ka] Step 1. To a stirred solution of tert-butoxide potassium (38.7 mg, 0.35 mmol) in dimethyl sulfoxide (5 mL), a solution of diethyl malonate (58 mg, 0.35 mmol) in DMSO (1 mL) was added dropwise over 10 minutes, and the mixture was stirred at room temperature for 40 minutes. A solution of 5-(2-bromopropanoyl)-7-chloro-2,3-dihydro-1H-isoindole-1-one (80 mg, 0.27 mmol) in DMSO (1 mL) was added dropwise over 10 minutes at 0°C under an argon atmosphere. The resulting mixture was slowly warmed to room temperature and stirred for 3 hours. After completion, the reaction mixture was quenched with saturated ammonium chloride aqueous solution at 0°C and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (30-50% toluene in hexane) to obtain 1,3-diethyl 2-[1-(7-chloro-1-oxo-2,3-dihydro-1H-isoindole-5-yl)-1-oxopropan-2-yl]propanedioate (55 mg, 54%) as a yellow solid. MS(ESI): m / z 382[M+1]+.

[0099] Step 2. A solution of diethyl 1,3-diethyl 2-[1-(7-chloro-1-oxo-2,3-dihydro-1H-isoindole-5-yl)-1-oxopropan-2-yl]propanedioate (220 mg, 0.58 mmol) in 6 N hydrochloric acid aqueous solution (8 mL) was heated at 90°C for 16 hours. After completion, volatiles were removed under reduced pressure, and the residue was distilled twice with toluene. The crude product was pulverized with diethyl ether to obtain 4-(7-chloro-1-oxo-2,3-dihydro-1H-isoindole-5-yl)-3-methyl-4-oxobutanoic acid (90 mg, 55%) as a brown gum, which was then removed without further purification and proceeded to the next step. MS(ESI): m / z 282.0[M+1]+.

[0100] Step 3. To a stirred solution of 4-(7-chloro-1-oxo-2,3-dihydro-1H-isoindol-5-yl)-3-methyl-4-oxobutanoic acid (80.0 mg, 0.28 mmol) in ethanol (10 mL), hydrazine monohydrate (0.1 ml, 1.14 mmol) was added at room temperature. The resulting mixture was heated at 90 °C for 16 hours. After completion, volatile matter was removed under reduced pressure, and the resulting crude product was purified by reverse-phase preparative HPLC to obtain the compound of Example #39 (9 mg) as an off-white solid (99.89% purity). 1H NMR(400MHz,DMSO-d6):δ11.17(s,1H),8.74(s,1H),7.90(s,1H),7.80(s,1H),4.37(s ,2H),3.46-3.43(m,1H),2.77-2.66(m,1H),2.32-2.25(m,1H),1.08(d,J=7.2Hz,3H).

[0101] Example #7, 7-(4-chlorophenyl)-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one was prepared according to the following steps: [ka] Step 1: To a stirred solution of 7-bromo-2,3-dihydro-1H-indole-2-one (200.0 mg, 0.94 mmol) in 1,4-dioxane (5.0 ml) and water (2.0 ml), potassium phosphate (500 mg, 2.36 mmol), followed by 4-chlorophenylboronic acid (222 mg, 1.42 mmol), was added, and the resulting mixture was purged with argon for 10 minutes. Pd(dppf)Cl2.CH2Cl2 (77.0 mg, 0.09 mmol) was added, and the reaction mixture was heated at 100°C for 16 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (10-15% siRNA in hexane) to obtain 7-(4-chlorophenyl)-2,3-dihydro-1H-indole-2-one (160 mg, 70%) as a brown solid. MS(ESI): m / z 244.02[M+1]+.

[0102] Step 2: To a stirred solution of 7-(4-chlorophenyl)-2,3-dihydro-1H-indole-2-one (100.0 mg, 0.41 mmol) in trifluoroacetic acid (3.0 ml), N-bromosuccinimide (52.0 mg, 0.53 mmol) was added in small increments, and the reaction mixture was stirred at room temperature for 16 hours. After completion, volatiles were removed under reduced pressure. The residue was diluted with water and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude mass was purified by combiflash column chromatography (10-15% Â in hexane) to obtain 5-bromo-7-(4-chlorophenyl)-2,3-dihydro-1H-indole-2-one (60 mg, 45%) as an off-white solid. MS(ESI): m / z 323.8[M+1]+.

[0103] Step 3: To a stirred solution of 5-bromo-7-(4-chlorophenyl)-2,3-dihydro-1H-indole-2-one (250.0 mg, 0.77 mmol) in 1,4-dioxane (5.0 ml), bis(pinacolate)-diborone (238 mg, 0.93 mmol), followed by potassium acetate (153 mg, 1.55 mmol), was added, and the resulting mixture was purged with argon for 10 minutes. Pd(dppf)Cl2.CH2Cl2 (64 mg, 0.07 mmol) was added, and the reaction mixture was heated at 85°C for 16 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude aggregate was purified by combiflash column chromatography (30-40% siRNA in hexane) to obtain 7-(4-chlorophenyl)-5-(tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3-dihydro-1H-indole-2-one (200 mg, 69%) as an off-white solid. MS(ESI): m / z 370.3[M+1]+.

[0104] Step 4: To a stirred solution of 7-(4-chlorophenyl)-5-(tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3-dihydro-1H-indole-2-one (200.0 mg, 0.54 mmol) in 1,4-dioxane (10.0 ml) and water (2.0 ml), potassium phosphate (288.0 mg, 1.35 mmol) was added, followed by 6-bromo-2,3-dihydropyridazine-3-one (143.0 mg, 0.81 mmol), and the resulting mixture was purged with argon for 10 minutes. Pd(dppf)Cl2.CH2Cl2 (44.0 mg, 0.05 mmol) was added, and the reaction mixture was heated at 100°C for 16 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (50-60% toluene in hexane) to obtain the compound of Example #7 (10 mg, 6%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d6): δ 13.10 (s, ¹H), 10.49 (s, ¹H), 8.01 (s, ¹H), 7.74 (s, ¹H), 7.65 (s, ¹H), 7.52 (s, ⁴H), 6.95 (d, J=10 Hz, ¹H), 3.63 (s, ⁴H).

[0105] In Example #9, 8-(4-chlorophenyl)-6-(6-oxo-1,6-dihydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one was prepared in the same manner as in Example #7, but the compound of Example #9 was obtained by using 6-bromo-3,4-hydroquinolone instead of 7-bromo-2,3-dihydro-1H-indole-2-one. 1H NMR(400MHz,DMSO-d6):δ13.11(s,1H),9.01(s,1H),8.08(d,J=9.6Hz,1H),7.76(s,1H),7.55 -7.53(m,3H),7.46-7.44(m,2H),6.96(d,J=9.6Hz,1H),3.01-2.98(m,2H),2.52-2.48(m,2H).

[0106] The preparation of Example #8, 7'-chloro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)spiro[cyclopropan-1,3'-indoline]-2'-one was prepared according to the following steps: [ka] Step 1. A slurry of anhydrous AlCl3 (20.97 g, 157.23 mmol) and DMF (0.004 mL, 47.17 mmol) was heated at 70°C for 15 minutes, then cooled to 40°C. Spiro[cyclopropane-1,3'-indoline]-2'-one (2.5 g, 15.72 mmol) and 3-methyldihydrofuran-2,5-dione (2.15 g, 18.89 mmol) were slowly added. The resulting mixture was heated at 70°C for 2 hours, poured into ice-cold water, and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was ground with diethyl etherpentane to obtain 3-methyl-4-oxo-4-{2'-oxo-1',2'-dihydrospiro[cyclopropane-1,3'-indole]-5'-yl}butanoic acid (3.0 g, mixture of crude products) as a brown gum. The next step was carried out without further purification. MS(ESI): m / z 274.2[M+1] + .

[0107] Step 2. To a stirred solution of 3-methyl-4-oxo-4-{2'-oxo-1',2'-dihydrospiro[cyclopropane-1,3'-indole]-5'-yl}butanoic acid (3.0 g, 10.99 mmol) in ethanol (30.0 mL), hydrazine monohydrate (1.41 mL, 43.96 mmol) was added. The resulting mixture was heated at 80°C for 16 hours. Crude LC-MS showed the formation of two peaks with product mass (undesirable:desirable = 4:1). The reaction mixture was evaporated under reduced pressure, the residue was incorporated into EtOH, and stirred under cooling. The solid thus formed was filtered and discarded [containing the undesirable major isomer]. The filtrate was concentrated under reduced pressure, and the crude mass was purified by combiflash column chromatography (60-70% ethyl acetate in hexane) to obtain 5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1',2'-dihydrospiro[cyclopropane-1,3'-indole]-2'-one (270 mg, 7% in 2 steps) as an off-white solid. MS(ESI): m / z 270.2[M+1] + .

[0108] Step 3. To a stirred solution of 5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1',2'-dihydrospiro[cyclopropane-1,3'-indole]-2'-one (270.0 mg, 1.00 mmol) in DMF (5.0 mL), NCS (200.99 mg, 1.51 mmol) was added at room temperature. The resulting reaction mixture was heated at 70 °C for 3 hours. After completion, the reaction mixture was diluted with ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (50-60% ethyl acetate in hexane) to obtain the compound of Example #8. 1H NMR(400MHz,DMSO-d6):δ11.16(s,1H),10.90(s,1H),7.61(s,1H),7.35(s,1H),3.41-3.38(m,1H),2 .68-2.62(m,1H),2.22(d,J=16.8Hz,1H),1.71-170(m,2H),1.55-154(m,2H),1.03(d,J=7.2Hz,3H).

[0109] Example #19 Preparation of (6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one) [ka] Step 1: To a stirred solution of 1-(4-methoxyphenyl)cyclopropane-1-carboxylic acid (200 mg, 1.04 mmol) in DMF (5 mL) at 0°C, 4-methylmorpholine (0.23 mL, 2.08 mmol), followed by HATU (395.64 mg, 1.041 mmol), was added, and the resulting mixture was stirred at 0°C for 10 minutes. 6-(3,4-diaminophenyl)-5-methyl-2,3,4,5-tetrahydropyridazine-3-one (227 mg, 1.04 mmol) was added, and the resulting mixture was stirred at room temperature for 16 hours. After completion, the reaction mixture was diluted with water and extracted with 10% MeOH in DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain N-[2-amino-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)phenyl]-1-(4-methoxyphenyl)cyclopropane-1-carboxamide (200 mg, crude) as a yellow semi-solid [a mixture of two positional isomers]. This was used in the next step without further purification. MS(ESI): m / z 392.9 and 393.3 [M+1] + .

[0110] Step 2. A stirred solution of N-[2-amino-4-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)phenyl]-1-(4-methoxyphenyl)cyclopropane-1-carboxamide (200 mg, 0.53 mmol) in acetic acid (5 mL) was heated at 100 °C for 16 hours. The reaction mixture was cooled to room temperature, and volatiles were removed under reduced pressure. The crude product thus obtained was purified by reverse-phase preparative HPLC to obtain the compound of Example #19 (110 mg, 58%) as an off-white solid. 1H NMR (400MHz, DMSO-d6): δ11.79&11.74(s,1H),10.85&10.83(s,1H),7.86&7. 69(s,1H),7.66&7.56(d,J=8.2Hz,1H),7.49&7.33(d,J=8.2Hz,1H),7.35-7.3 1(m,2H),6.94(m,2H),3.76(s,3H),3.46&3.37(m,1H),2.72&2.68(m,1H),2. 25&2.20(m,1H),1.60-1.57(m,2H),1.33-1.30(m,2H),1.08(d,J=6.8Hz,3H). LC-MS: Retention time = 2.20 min, HPLC purity = 99.72%. Note: 1H NMR showed that the product is a mixture of isomers.

[0111] Example #21: Preparation of (5-methyl-6-(1-methyl-2-(phenylamino)-1H-benzo[d]imidazole-6-yl)-4,5-dihydropyridazine-3(2H)-one) [ka] Step 1. Isothiocyanatobenzene (1.2 mL, 10.00 mmol) in N,N-dimethylformamide (15 mL) at room temperature was added to a solution of 3-(3,4-diaminophenyl)-4-methyl-4,5-dihydro-1H-pyridazin-6-one (2.183 g, 10.00 mmol) in N,N-dimethylformamide (15 mL), and the contents were stirred at room temperature. Then, after 2 hours, N,N'-diisopropylmethandiimine (1.86 mL, 12.00 mmol) was added to the reaction mixture, and the contents were stirred overnight at 70°C. The reaction mixture was then cooled to room temperature and purified directly by reverse-phase chromatography to obtain 3-(2-anilino-3H-benzimidazole-5-yl)-4-methyl-4,5-dihydro-1H-pyridazin-6-one (m / z[M+H]=320).

[0112] Step 2. A 60% sodium hydride dispersion in mineral oil (138 mg, 3.44 mmol) was added to a solution of 3-(2-anilino-3H-benzimidazole-5-yl)-4-methyl-4,5-dihydro-1H-pyridazine-6-one (1.00 g, 3.13 mmol) in tetrahydrofuran (20 mL) at 0°C and stirred for 1 hour. Then, methyl iodide (0.214 mL, 3.44 mmol) was added and the mixture was stirred overnight. The resulting mixture was diluted with ethyl acetate and washed with water and brine. The organic layer was concentrated under reduced pressure, and the residue was purified by reverse-phase preparative HPLC to obtain the compound of Example #21. dH(d6-DMSO)10.83(s,1H),9.00(s,1H),7.87(d,2H),7.71(s,1H),7.55(d,1H),7.25-7.40( m,3H),6.97(t,1H),3.75(s,3H),3.45-3.60(m,1H),2.70(dd,1H),2.26(d,1H),1.12(d,3H).

[0113] Preparation of Example #24 (7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indolin-2-one) [ka] Step 1: To a stirred solution of 3,3-dimethyl-2,3-dihydro-1H-indole-2-one (5.0 g, 31.02 mmol) in 1,2-dichloroethane (150 mL) at 0 °C, anhydrous aluminum chloride (10.4 g, 77.54 mmol) was added and the mixture was stirred at 10 °C for 30 minutes. Propionyl chloride (5.8 g, 62.04 mmol) was added dropwise to the reaction mixture and the mixture was stirred at 80 °C for 16 hours. After completion, the reaction mixture was diluted with ice-cold water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (30-40% siRNA in hexane) to obtain 3,3-dimethyl-5-propanoyl-2,3-dihydro-1H-indole-2-one (3 g, 44%) as an off-white solid. MS(ESI):m / z 218.0[M+1]+ .

[0114] Step 2. A solution of 3,3-dimethyl-5-propanoyl-2,3-dihydro-1H-indol-2-one (2 g, 9.20 mmol) in THF (30 mL) was added to a stirred solution of LiHMDS (11.1 mL, 11.1 mmol, 1 M in THF) in THF (30 mL) at -78 °C, and the resulting mixture was stirred at -78 °C for 1 hour. A solution of ethyl 2-bromoacetate (1.85 g, 11.05 mmol) in THF (30 mL) was added dropwise over 20 minutes, and the mixture was stirred at -78 °C for an additional 1 hour. After completion, the reaction mixture was quenched with 1 N HCl and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (40 - 50% EtOAc in hexanes) to give ethyl 4-(3,3-dimethyl-2-oxo-2,3-dihydro-1H-indol-5-yl)-3-methyl-4-oxobutanoate (900 mg, 32%) as a white solid. MS (ESI): m / z 304.0 [M+1] + .

[0115] Step 3. To a stirred solution of ethyl 4-(3,3-dimethyl-2-oxo-2,3-dihydro-1H-indol-5-yl)-3-methyl-4-oxobutanoate (700 mg, 2.31 mmol) in EtOH (20 mL) and MeOH (5 mL) at 0 °C, LiOH·H2O (11.5 mL, 11.54 mmol, 1 M in H2O) was added dropwise, and the mixture was stirred at room temperature for 16 hours. After completion, the reaction mixture was evaporated under reduced pressure, the residue was diluted with water, and extracted with 50% ethyl acetate in hexanes. The organic portion was discarded. The aqueous portion was acidified to pH ~4 with 2 N HCl and extracted with 10% MeOH in ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to give (3,3-dimethyl-2-oxo-2,3-dihydro-1H-indol-5-yl)-3-methyl-4-oxobutanoic acid (470 mg, 74%) as a white solid. MS (ESI): m / z 274.4 [M-1] + .

[0116] Step 4. To a stirred solution of 4-(3,3-dimethyl-2-oxo-2,3-dihydro-1H-indole-5-yl)-3-methyl-4-oxobutanoic acid (470 mg, 1.71 mmol) in ethanol (15 mL), hydrazine monohydrate (89.7 mg, 1.79 mmol) was added and the mixture was stirred at 80°C for 16 hours. After completion, volatile matter was removed under reduced pressure, and the crude product was purified by combiflash column chromatography (60-70% ethyl acetate in hexane) to obtain 3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2,3-dihydro-1H-indole-2-one (200 mg, 43%) as an off-white solid. MS(ESI): m / z 271.9[M+1] + .

[0117] Step 5. To a stirred solution of 3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2,3-dihydro-1H-indole-2-one (50 mg, 0.18 mmol) in DMF (1 mL), N-chlorosuccinimide (27 mg, 0.2 mmol) was added and stirred at room temperature for 1 hour. After completion, the reaction mixture was poured into ice water. The resulting solid was filtered, washed with diethyl ether, and dried under vacuum to obtain the compound of Example #24 (20 mg, 35%) as a white solid. ¹H NMR (400MHz, DMSO-d6): δ 10.95 (s, ¹H), 10.92 (s, ¹H), 7.71 (s, ¹H), 7.62 (s, ¹H), 3.42-3.37 (m, ¹H), 2.71-2.65 (m, ¹H), 2.22 (d, J=16.8Hz, ¹H), 1.30 (s, ⁶H), 1.06 (d, J=7.2Hz, ³H). LCMS: Retention time = 1.56 min, HPLC purity = 98.00%. The enantiomers of Example #24 are Example #33 and Example #51. Example #33 was the (R)-isomer and was decomposed by HPLC at a flow rate of 1.0 mL / min (Chiralpak IG column 250x4.6 mm, 5 μm, mobile phase (hexane / DCM / EtOH / isopropylamine (50 / 25 / 25 / 0.1))). The HPLC retention times for Examples #33 and #24 were 5.88 minutes and 6.63 minutes, respectively.

[0118] In Example #23, 7-bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one was prepared in the same manner as in Example #24, but 7-bromo-3,3-dimethylindorin-2-one was used instead of 7-chloro-3,3-dimethylindorin-2-one to obtain the compound of Example #23. ¹H NMR (400MHz, DMSO-d6): δ 10.92 (s, ¹H), 10.83 (s, ¹H), 7.74 (s, ²H), 3.42-3.38 (m, ¹H), 2.70-2.65 (m, ¹H), 2.22 (d, J=16.8Hz, ¹H), 1.29 (s, ⁶H), 1.05 (d, J=7.2Hz, ³H).

[0119] Preparation of Example #26 (7-fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indolin-2-one) [ka] Step 1. To a stirred solution of 7-fluoroindolin-2-one (5 g, 33.11 mmol) in dry THF (50 mL), lithium chloride (4.2 g, 99.34 mmol) was added, and the resulting mixture was cooled to -78°C. Lithium diisopropylamide (33.1 mL, 66.2 mmol, 2.0 M in THF / heptane / ethylbenzene) was added, and the mixture was stirred at -78°C for 15 minutes. Methyl iodide (1.8 mL, 66.2 mmol) was added, and the reaction mixture was stirred at room temperature for 5 hours. After completion, the reaction mixture was quenched with aqueous ammonium chloride and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by column chromatography (10-20% siRNA in hexane) to obtain 7-fluoro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (2.7 g, 46%) as a white solid. MS(ESI): m / z 180.1[M+1]+.

[0120] Step 2. DMF (3.78 mL, 49.54 mmol) was added dropwise to anhydrous AlCl3 (19.98 g, 150.12 mmol), and the resulting mixture was stirred at 70°C for 15 minutes, then cooled to 40°C. 7-Fluoro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (2.7 g, 15.08 mmol) and 2-chloropropanoyl chloride (1.86 ml, 18.75 mmol, 1.25 equivalents) were slowly added to the AlCl3 solution and heated at 70°C for 4 hours. After completion, the reaction mixture was allowed to reach ambient temperature, slowly poured onto crushed ice, and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by column chromatography (10-20% siRNA in hexane) to obtain 5-(2-chloropropanoyl)-7-fluoro-3,3-dimethylindorin-2-one (1.4 g, 35%) as a yellow solid. MS(ESI): m / z 270.2[M+1]+.

[0121] Step 3. To a stirred solution of tert-butoxide potassium (850 mg, 7.55 mmol) in DMSO (20 mL), diethyl malonate (1.2 gm, 7.55 mmol) in DMSO (12 mL) was added dropwise over 10 minutes. The solution was stirred for 20 minutes, and 5-(2-chloropropanoyl)-7-fluoro-3,3-dimethylindorin-2-one (1.4 gm, 5.8 mmol) in DMSO (5 mL) was added. The resulting mixture was stirred at room temperature for 3 hours. After completion, the reaction mixture was quenched with acetic acid (0.6 mL, 10 mmol) and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by column chromatography (30-40% ethyl acetate in hexane) to obtain diethyl 2-(1-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-1-oxopropan-2-yl)malonate (800 mg, 27%) as an off-white solid. MS(ESI): m / z 394.1[M+1]+.

[0122] Step 4. A solution of diethyl 2-(1-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-1-oxopropan-2-yl)malonate (800 mg, 2.03 mmol) in 6N HCl (50 ml) and dioxane (15 mL) was heated at 90°C for 16 hours. The reaction mixture was cooled to room temperature, diluted with water, and ethyl acetate was extracted. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain 4-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-3-methyl-4-oxobutanoic acid (600 mg, crude) as a colorless gum. MS(ESI): m / z 294.3[M+1]+.

[0123] Step 5. To a stirred solution of 4-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-3-methyl-4-oxobutanoic acid (600 mg, crude) in ethanol (20 mL), hydrazine monohydrate (3 mL) was added and the mixture was heated at 90°C for 16 hours. After completion, the reaction mixture was quenched with water and extracted with 10% MeOH in DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by column chromatography (1-5% MeOH in DCM) to obtain the compound of Example #26 (340 mg, 54% in 2 steps) as an off-white solid. 1H NMR(400MHz,DMSO-d6):δ11.02(s,1H),10.92(s,1H),7.61(s,1H),7.50-7.48(m,1H), 3.40-3.38(m,1H),2.689-2.66(m,1H),2.24-2.20(m,1H),1.29(s,6H),1.05(bs,3H). Retention time = 6.11 min, HPLC purity = 96.27%

[0124] Preparation of Example #27 (7-fluoro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indolin-2-one) [ka] Step 1. To a stirred solution of 7-fluoro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (2.7 gm, 15.08 mmol) in trifluoroacetic acid (30 mL), N-bromosuccinimide (4 g, 22.63 mmol) was added in small increments, and the reaction mixture was stirred at room temperature for 16 hours. After completion, the trifluoroacetic acid was evaporated under reduced pressure. The residue was diluted with ethyl acetate, and the water and layers were separated. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (30-40% ethyl acetate in hexane) to obtain 5-bromo-7-fluoro-3,3-dimethylindolin-2-one (2 g, 52%) as an off-white solid. MS(ESI): m / z 257.6[M+1]+.

[0125] Step 2. To a stirred solution of 5-bromo-7-fluoro-3,3-dimethylindorin-2-one (2 g, 7.72 mmol) in dioxane (5 mL), bis(pinacolate)diborone (2.37 g, 9.33 mmol), followed by KOAc (1.51 g, 15.44 mmol), the resulting mixture was purged with argon for 10 minutes. Pd(dppf)Cl2·DCM (630 mg, 0.772 mmol) was added, and the reaction mixture was heated at 95°C for 16 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (30-40% ethyl hexane) to obtain 7-fluoro-3,3-dimethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)indorin-2-one (1.5 g, 63%) as an off-white solid. MS(ESI): m / z 305.9[M+1]+.

[0126] Step 3. 7-Fluoro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indoline-2-one To a mixture of 1,4-dioxane (15 mL) and water (5 mL), 7-fluoro-3,3-dimethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)indorin-2-one (1.5 g, 4.92 mmol) was stirred, followed by the addition of 6-bromo-2,3-dihydropyridazine-3-one (1.29 g, 7.38 mmol), and then K3PO4 (2.61 g, 12.3 mmol). The resulting mixture was purged with argon for 10 minutes. Pd-118 (321 mg, 0.49 mmol) was added, and the reaction mixture was heated in a sealed tube at 100°C for 16 hours. After completion, the reaction mixture was diluted with water and extracted with 10% MeOH in DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product obtained in this manner was purified by combiflash column chromatography (1-5% MeOH in DCM) to obtain the compound of Example #27 (220 mg, 17%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d6): δ 13.16 (s, ¹H), 11.04 (s, ¹H), 8.06 (d, J=9.9 Hz, ¹H), 7.71 (s, ¹H), 7.61 (d, J=11.7 Hz, ¹H), 6.99 (d, J=9.9 Hz, ¹H), 1.32 (s, ⁶H). LCMS: Retention time = 1.80 min, HPLC purity = 98.01%

[0127] Preparation of Example #28 (7'-fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropane-1,3'-indoline]-2'-one) [ka] Step 1. A slurry of AlCl3 (7.5 g, 56.44 mmol) and DMF (1.3 mL, 16.93 mmol) was heated at 70°C for 15 minutes, then cooled to 40°C. 7'-Fluorospiro[cyclopropane-1,3'-indoline]-2'-one (1.0 g, 5.64 mmol) and 3-methyldihydrofuran-2,5-dione (590 mg, 7.34 mmol) were slowly added. The resulting mixture was heated at 70°C for 8 hours, poured onto crushed ice, and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was ground with diethyl etherpentane to obtain a mixture of 4-(7'-fluoro-2'-oxospiro[cyclopropan-1,3'-indoline]-5'-yl)-3-methyl-4-oxobutanoic acid and 4-(7'-fluoro-2'-oxospiro[cyclopropan-1,3'-indoline]-5'-yl)-2-methyl-4-oxobutanoic acid (800 mg, crude product, desirable:undesirable = 1:4) as a brown gum. The process proceeded to the next step without further purification. MS(ESI): m / z 291.7[M+1]+.

[0128] Step 2. To a stirred solution of 4-(7'-fluoro-2'-oxospiro[cyclopropane-1,3'-indoline]-5'-yl)-3-methyl-4-oxobutanoic acid (800.0 mg, 2.75 mmol) in ethanol (20.0 mL), hydrazine monohydrate (0.66 mL, 13.74 mmol) was added. The resulting mixture was heated at 80°C for 16 hours. Crude LC-MS showed the formation of two peaks with product mass (undesirable:desirable = 4:1). The reaction mixture was evaporated under reduced pressure, the residue was incorporated into EtOH, and stirred under cooling. The solid thus formed was filtered and discarded [containing the undesirable major isomer]. The filtrate was concentrated under reduced pressure and purified by reverse-phase HPLC to obtain the compound of Example #28 (60 mg, 4% in 2 steps) as an off-white solid. 1H NMR(400MHz,DMSO-d6):δ10.90(bs,2H),7.48(d,J=12Hz,1H),7.26(s,1H),3.38(t,J=7.0Hz,1H), 2.68-2.62(m,1H),2.24-2.20(m,1H),1.71-1.69(m,2H),1.54-1.53(m,2H),1.04(d,J=7.2Hz,3H). LCMS: retention time = 2.11 min, HPLC purity = 99.66%

[0129] Example #30 Preparation of (6-(2-amino-4-chlorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one) [ka] Step 1: 6-(4-amino-3-chlorophenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one To a solution of 3-(4-aminophenyl)-4-methyl-4,5-dihydro-1H-pyridazin-6-one (2.0 g, 9.8 mmol) in DMF (15 mL), NCS (1.31 g, 9.8 mmol) was added. The reaction mixture was heated to 45 °C and stirred overnight. Next, the reaction mixture was cooled to room temperature, diluted with water, and extracted with siRNA:MeOH (90:10 2 × 100 mL). The combined organic phase was dried (Na₂SO₄) and concentrated under vacuum. The crude product was subjected to chromatography (40 g Redi-Sep column) eluting from 100% hexane to 60:40 siRNA to obtain a solid intermediate (1.52 g, 65%). LC / MS M+H=238.

[0130] Step 2: Potassium thiocyanate (3.3 g, 33.6 mmol) was added to a solution of 6-(4-amino-3-chlorophenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one (2.0 g, 8.4 mmol) in AcOH (50 mL), which had been slightly cooled in an ice bath. The contents were stirred at room temperature for 15 minutes. Next, bromine (0.45 mL, 8.4 mmol) dissolved in AcOH (2 mL) was added dropwise, and the reaction mixture was stirred at room temperature overnight. The reaction mixture was neutralized with saturated NaHCO3, the resulting precipitate was filtered, and the mixture was air-dried to obtain the intermediate as an orange solid (2.9 g, 97%). 500 mg of the crude product was purified by SFC chromatography to obtain the compound of Example #30 (253 mg) as a solid. LC / MS M+H=295;1H NMR(400MHz,DMSO-d6):δ10.94(s,1H),8.06(s,1H),8.02(br s, 2H), 7.71 (s, 1H), 3.40 (q, 1H), 2.70-2.66 (m, 1H), 2.23 (d, 1H), 1.07 (d, 3H).

[0131] Example #31: Preparation of 6-(2-amino-4-fluorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one [ka] Step 1: 4-(3,4-difluorophenyl)-3-methyl-4-oxobutanoate A 1M solution of KHMDS in THF (22.0 mL, 22.0 mmol) was added to THF (25 mL) in a round-bottom flask and cooled to -78°C. Next, 1-(3,4-difluorophenyl)propan-1-one (3.75 g, 22.0 mmol) in 10 mL of THF was added dropwise, and the reaction mixture was stirred at -78°C for 1 hour. 2-ethyl bromoacetate (4.8 g, 28.6 mmol) in 10 mL of THF was slowly added, and the reaction mixture was warmed to 0°C while stirring for 1 hour. The reaction mixture was quenched with 1N HCl and extracted with SiO2 (2 × 75 mL). The combined organic phase was dried to (Na2SO4) and concentrated under vacuum. The crude product was subjected to chromatography (using a 120g Redi-Sep column) eluting from 100% hexane to 10:90 siRNA, yielding a clear oil intermediate (3.9g, 69%). LC / MS M+H=257.

[0132] Step 2: 6-(3-fluoro-4-hydrazinylphenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one To a solution of ethyl 4-(3,4-difluorophenyl)-3-methyl-4-oxo-butanoate (1.0 g, 3.9 mmol) in 2-MeTHF (15 mL), hydrated hydrazine (0.5 mL, 15.6 mmol) was added. The reaction mixture was heated to 110 °C for 6 hours under microwave irradiation. Next, the crude mixture was cooled in an ice bath with stirring, the resulting precipitate was filtered, washed with cold EtOH, and air-dried to obtain a colorless solid intermediate (0.7 g, 76%). LC / MS M+H=237.

[0133] Step 3: 6-(4-amino-3-fluorophenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one To a solution of 6-(3-fluoro-4-hydrazinylphenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one (750 mg, 3.2 mmol) in MeOH (200 mL) and AcOH (1 mL), 10% Pd / C (200 mg) was added. The reaction mixture was hydrogenated at room temperature on a Parr shaker at 20 psi for 2 hours and then filtered through Celite. The mother liquor was concentrated under vacuum to obtain the intermediate as a semi-solid (0.67 g, 95%). LC / MS M+H=222.

[0134] Step 4: Potassium thiocyanate (1.9 g, 19.9 mmol) was added to a solution of 6-(4-amino-3-fluorophenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one (1.1 g, 4.9 mmol) in AcOH (35 mL), which had been slightly cooled in an ice bath. The contents were stirred at room temperature for 15 minutes. Bromine (0.25 mL, 4.9 mmol) dissolved in AcOH (1 mL) was then added dropwise, and the reaction mixture was stirred at room temperature overnight. The reaction mixture was neutralized with saturated NaHCO3 and extracted with ELISA:MeOH (100 mL, 90:10) to obtain the crude product (1.2 g, 88%) as a concentrated gum. 100 mg of the crude product was purified over 20 minutes using reverse-phase chromatography, eluting from 95:5:0.1 water:MeCN:TFA to 80:20:0.1 MeCN:water:TFA, to obtain the compound of Example #31 (31 mg) as a solid. LC / MS M+H=279;1H NMR (400 MHz, DMSO-d6): δ 10.94 (s,1H), 7.95 (s,1H), 7.91 (br s,2H), 7.50 (d,1H), 3.39 (q,1H), 2.71-2.67 (m,1H), 2.23 (d,1H), 1.08 (d,3H).

[0135] Preparation of Example #32 (7-bromo-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indolin-2-one) [ka] Step 1. To a stirred solution of 5-bromoindorin-2-one (5 g, 23.58 mmol) in dry THF (50 mL), lithium chloride (2.9 g, 70.75 mmol) was added, and the resulting mixture was cooled to -78°C. Lithium diisopropylamide (23.5 mL, 47.17 mmol, 2.0 M in THF / heptane / ethylbenzene) was added, and the mixture was stirred at -78°C for 15 minutes. Methyl iodide (2.9 mL, 47.17 mmol) was added, and the reaction mixture was stirred at room temperature for 5 hours. After completion, the reaction mixture was quenched with aqueous ammonium chloride and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by column chromatography (10-20% siRNA in hexane) to obtain 5-bromo-3,3-dimethylindorin-2-one (2.3 g, 41%) as a white solid. MS(ESI): m / z 240[M+1]+.

[0136] Step 2. To a stirred solution of 5-bromo-3,3-dimethylindorin-2-one (2.3 g, 9.58 mmol) in dioxane (15 mL), bis(pinacolate)diborone (2.9 g, 11.5 mmol), followed by KOAc (1.8 g, 19.16 mmol), the resulting mixture was purged with argon for 10 minutes. Pd(dppf)Cl2·DCM (0.783 g, 0.958 mmol) was added, and the reaction mixture was heated at 95°C for 16 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (30-40% ethyl hexane) to obtain 3,3-dimethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3-dihydro-1H-indole-2-one (1.45 g, 53%) as an off-white solid. MS(ESI): m / z 288[M+1]+.

[0137] Step 3. Add 3,3-dimethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3-dihydro-1H-indole-2-one (640 mg, 2.23 mmol) to a mixture of 1,4-dioxane (10 mL) and water (5 mL) with a stirring solution, then add 6-bromo-2,3-dihydropyridazine-3-one (585 mg, 3.34 mmol), followed by K3PO4 (1.2 g, 5.57 mmol), and purge the resulting mixture with argon for 10 minutes. Add Xphos (213 mg, 0.446 mmol) and Xphos Pd G3 (175 mg, 0.223 mmol), and heat the reaction mixture in a sealed tube at 100 °C for 16 hours. After completion, dilute the reaction mixture with water and extract with 10% MeOH in DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (1-5% MeOH in DCM) to obtain 3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazin-3-yl)-2,3-dihydro-1H-indole-2-one (170 mg, 30%) as an off-white solid. MS(ESI): m / z 256[M+1]+.

[0138] Step 4. To a stirred solution of 3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazin-3-yl)-2,3-dihydro-1H-indole-2-one (170 mg, 0.667 mmol) in DMF (5 mL), N-bromosuccinimide (142 mg, 0.8 mmol) was added in small increments, and the resulting mixture was stirred at room temperature for 16 hours. After completion, the reaction mixture was diluted with water and extracted with 10% MeOH in DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained (Example #32) was purified by combiflash chromatography (1-5% MeOH in DCM) to obtain the compound of Example #32 (65 mg, 29%) as an off-white solid. 1H NMR (400MHz, DMSO-d6): δ13.15 (br s, 1H), 10.85 (br s, 1H), 8.07 (d, J = 10 Hz, 1 H), 7.86 (s, 1 H), 7.83 (s, 1 H), 6.98 (d, J = 11.2 Hz, 1 H), 3.31 (s, 6 H). LCMS: retention time = 2.17 min, HPLC purity [at 254 nm] = 98.61%

[0139] Example #34 Preparation of (6-(4-fluoro-2-(methylamino)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one) [ka] Step 1.3-(2-amino-4-fluoro-1,3-benzothiazole-6-yl)-4-methyl-4,5-dihydro-1H-pyridazin-6-one (1.0 g, 3.6 mmol) was packed into a mixture of copper powder (195 mg, 2.9 mmol) in concentrated HCl (10.0 mL) and water (3.0 mL) at 0°C. Next, excess NaNO2 (750 mg, 10.8 mmol) dissolved in 3 mL of water was slowly added. The reaction mixture was warmed to room temperature and stirred for 3 hours. The reaction mixture was then diluted with water (25 mL), filtered, and air-dried to obtain 6-(2-chloro-4-fluorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazin-3(2H)-one as a solid (598 mg, 56%). LC / MS M+H=298.

[0140] Step 2. To a solution of 3-(2-chloro-1,3-benzothiazole-6-yl)-4-methyl-4,5-dihydro-1H-pyridazin-6-one (55 mg, 0.2 mmol) in EtOH (5 mL), N-methylamine (0.2 g, 2.0 mmol, 33 wt%) in EtOH was added. The reaction mixture was heated at 80°C for 2 hours and then cooled to room temperature. The crude product was purified over 20 minutes using reverse-phase chromatography, eluting from 95:5:0.1 water:MeCN:TFA to 75:25:0.1 MeCN:water:TFA, to obtain the compound of Example #34 (32 mg, 54%) as a solid. LC / MS M+H=293;1H NMR(400MHz,DMSO-d6):δ10.94(s,1H),8.34(br s,1H),7.96(s,1H),7.51(d,1H),3.39(q,1H),2.98(s,3H),2.71-2.67(m,1H),2.23(d,1H),1.08(d,3H).

[0141] In Example #37, the preparation of 6-(4-fluoro-2-(3-hydroxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one was carried out in the same manner as in Example #34, except that in step 2, 3-hydroxyazetidine HCl and K2CO3 in IPA were used instead of N-methylamine to obtain the compound of Example #37. 1H NMR (400MHz, DMSO-d6): δ10.97(s,1H),8.06(s,1H),7.55(d,1H),4.72-4.66(m,1H),4.40- 4.36(m,2H),3.96-3.92(m,2H),3.40(q,1H),2.71-2.67(m,1H),2.24(d,1H),1.08(d,3H).

[0142] In Example #46, the preparation of 6-(4-fluoro-2-(3-hydroxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one was carried out in the same manner as in Example #34, except that in step 2, (1-methylpyrazole-4-yl)methaneamine from IPA was used instead of N-methylamine to obtain the compound of Example #46. 1H NMR (400MHz, DMSO-d6): δ10.95(s,1H),8.61(t,1H),7.96(s,1H),7.69(s,1H),7.52(d,1H),7. 44(s,1H),4.43(d,2H),3.80(s,3H),3.39(q,1H),2.72-2.68(m,1H),2.24(d,1H),1.08(d,3H).

[0143] Example #35 Preparation of 8-chloro-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)quinoline-2(1H)-one [ka] Step 1. 2-Chloroaniline (1.0 g, 7.8 mMol) was dissolved in ethyl acetate (50 mL). Solid sodium bicarbonate (2.0 equivalents) was added, followed by 3-ethoxyacryloyl chloride (1.2 g, 9.4 mmol, 1.2 equivalents) at room temperature. The mixture was stirred for 3 hours and then quenched by adding water (10 mL). The reaction product was poured into a separatory funnel. The organic layer was collected and washed with water (2 × 15 mL). The organic phase was collected and dried over sodium sulfate. Volatile substances were removed by rotary evaporation to obtain (E)-N-(2-chlorophenyl)-3-ethoxyacrylamide, which was used directly in the next step.

[0144] Step 2. (E)-N-(2-chlorophenyl)-3-ethoxyacrylamide (0.80 g, 3.5 mmol) was added to cold sulfuric acid (5 mL). The solution was warmed to room temperature and stirred for 3 hours. The reaction mixture was poured into ice water (50 mL) and a precipitate formed. The precipitate was collected by suction filtration and washed with water before oven drying overnight to prepare 8-chloroquinoline-2(1H)-one (0.771 g, 4.3 mmol).

[0145] Step 3. While maintaining the temperature below 30°C, aluminum chloride (2.3 g, 17.2 mmol) was added in small amounts to a solution of 2-chloropropanoyl chloride (1.6 g, 12.9 mmol) in DCM (10 mL). While maintaining the temperature below 30°C, 8-chloroquinoline-2(1H)-one (0.771 g, 4.3 mmol) was added. The mixture was stirred, refluxed for 15 hours, cooled, and poured into ice water. The precipitate was filtered, washed with water, and taken into DCM (2 mL). The organic solution was stirred at 0°C and filtered. The precipitate was dried to obtain 0.79 g (2.7 mmol) of 8-chloro-6-(2-chloropropanoyl)quinoline-2(1H)-one.

[0146] Step 4. t-BuOK (490 mg, 4.4 mmol) was added to anhydrous DMSO (25 mL) under an N2 atmosphere. The mixture was stirred at 30°C for 30 minutes. Diethyl malonate (656 mg, 4.4 mmol) was diluted with DMSO (5 mL) and added dropwise to the stirred mixture over a period of 1 hour. The reaction solution was stirred at 30°C for a further 1 hour. 8-Chloro-6-(2-chloropropanoyl)quinoline-2(1H)-one (790 mg, 2.7 mmol) was added to the reaction mixture in three portions over 15 minutes. The reaction mixture was then stirred at 40°C for 2 hours. The reaction mixture was cooled to room temperature and quenched with acetic acid (2 mL). Water (100 mL) and methylene chloride (50 mL) were added to the reaction mixture in a separatory funnel. Each layer was mixed and divided. The organic phase was collected and washed with brine (3 × 20 mL). The organic phase was dried over sodium sulfate and concentrated to obtain the crude product, diethyl 2-(1-(8-chloro-2-oxo-1,2-dihydroquinoline-6-yl)-1-oxopropan-2-yl)malonate, which was used directly in the next step.

[0147] Step 5. Diethyl 2-(1-(8-chloro-2-oxo-1,2-dihydroquinoline-6-yl)-1-oxopropan-2-yl)malonate (2.7 mmol) was suspended in a 1:1 solution of dioxane / water (10 mL). Sodium hydroxide (0.540 g, 13.5 mmol) was added to the mixture. The mixture was heated at 60°C for 12 hours. The reaction mixture was allowed to cool to room temperature before adding AcOH (15 mmol). The reaction mixture was stirred for 10 minutes, then frozen and lyophilized to obtain a crude mixture of dihydrochloric acid and inorganic salt.

[0148] The mixture was suspended in EtOH, and hydrazine monohydrate (0.30 g, 6 mmol) was added to the mixture. The reaction was heated overnight at 65°C. The reaction mixture was allowed to cool to room temperature. The volatile components were evaporated using low-pressure rotary evaporation to obtain a white solid. Water (20 mL) was added to the solid, and the insoluble material was filtered out to obtain the crude product as a brown solid (0.4 g). Purification by reverse-phase HPLC yielded the compound of Example #35 (156 mg, 0.56 mmol). 1H NMR(400MHz,DMSO-d6)δppm1.05-1.13(m,3H)2.24-2.31(m,1H)2.68-2.77(m,1H)3.41-3 .51(m,1H)6.61-6.68(m,1H)8.01-8.10(m,3H)11.03-11.07(m,1H)11.22-11.27(m,1H).

[0149] Example #35 exists as the following tautomer, 6-(8-chloro-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one (#35a): [ka]

[0150] Preparation of Example #36 (7-chloro-6-fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indolin-2-one) [ka] Step 1. To a stirred solution of chloral hydrate (15.9 g, 96.18 mmol) and sodium sulfate (54.6 g, 384.72 mmol) in water (70 mL), 2-chloro-3-fluoroaniline (10.0 g, 68.7 mmol) in concentrated hydrochloric acid (6.9 mL) at room temperature was added and the mixture was stirred for 1 hour. Hydroxylamine hydrochloride (6.68 g, 96.18 mmol) was added to the reaction mixture, and the resulting mixture was heated at 80°C for 16 hours. The reaction mixture was poured into water and extracted with ethyl acetate. The organic layer was concentrated under reduced pressure to obtain (E)-N-(2-chloro-3-fluorophenyl)-2-(hydroxyimino)acetamide (10 g), which was then removed without further purification and proceeded to the next step. MS(ESI): m / z 217.2[M+1] + .

[0151] Step 2. Stir the mixture in a solution of (E)-N-(2-chloro-3-fluorophenyl)-2-(hydroxyimino)acetamide (10 g, 46.17 mmol) in concentrated sulfuric acid (30 mL) at 80°C for 3 hours. The reaction mixture was poured into ice water and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (20-40% ethyl acetate in hexane) to obtain 7-chloro-6-fluoroindoline-2,3-dione (5.6 g, 26%, after 2 steps) as an off-white solid. MS(ESI): m / z 200.2[M+1] + .

[0152] Step 3. To a stirred solution of 7-chloro-6-fluoroindolin-2,3-dione (5.6 g, 28.06 mmol) in ethylene glycol (50 mL), hydrazine monohydrate (2.81 g, 56.12 mmol) was added at room temperature, and the mixture was stirred at 130 °C for 4 hours, then at room temperature for 16 hours. Water (50 mL) and concentrated hydrochloric acid (5 mL) were added to the reaction mixture, and the mixture was stirred at 50 °C for 1 hour. The reaction mixture was poured into ice water and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (30-40% ethyl acetate in hexane) to obtain 7-chloro-6-fluoroindolin-2-one (3.9 g, 75%) as a brown solid. MS (ESI): m / z 186.2 [M+1] + .

[0153] Step 4. To a stirred solution of 7-chloro-6-fluoroindorin-2-one (3.9 g, 21.02 mmol) in tetrahydrofuran (40 mL), lithium chloride (2.67 g, 63.05 mmol) was added at room temperature. The reaction mixture was cooled to -78 °C, followed by the addition of LDA (2 M in THF, 21 mL, 42.03 mmol). The reaction mixture was stirred at -78 °C for 15 minutes, followed by the addition of methyl iodide (2.6 mL, 42.03 mmol). After the addition, the reaction mixture was allowed to reach room temperature and stirred for 2 hours. The reaction mixture was quenched with saturated ammonium chloride solution and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (20-30% ethyl acetate in hexane) to obtain 7-chloro-6-fluoro-3,3-dimethylindorin-2-one (1.5 g, 33%) as a brown solid. MS(ESI): m / z 214.2[M+1] + .

[0154] Step 5. To a stirred solution of 7-chloro-6-fluoro-3,3-dimethylindorin-2-one (3.0 g, 14.04 mmol) in concentrated sulfuric acid (30 mL), n-bromosuccinimide (3.75 g, 21.06 mmol) was added in small amounts at room temperature and stirred for 1 hour. The reaction mixture was poured into ice water and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (30-40% ethyl acetate in hexane) to obtain 5-bromo-7-chloro-6-fluoro-3,3-dimethylindorin-2-one (3.8 g, 92%) as an off-white solid. MS(ESI): m / z 292.2[M+1] + .

[0155] Step 6. Stirring in THF (30 mL): Add iPrMgCl.LiCl (10.52 mL, 2 equivalents, 1.3 M in THF) to nBuLi (13.4 mL, 28.32 mmol, 2 M in THF) at 0°C and stir for 10 minutes. Add a solution of 5-bromo-7-chloro-6-fluoro-3,3-dimethylindorin-2-one (2 g, 7.08 mmol) in THF (10 mL) to the reaction mixture and stir for 1 hour. Cool the reaction mixture to -78°C, add propionaldehyde (2.47 g, 42.47 mmol), and stir at -78°C for 2 hours. Quench the reaction mixture with saturated ammonium chloride and extract with ethyl acetate. Dry the organic layer over anhydrous sodium sulfate, filter, and concentrate under reduced pressure. The crude product was purified by combiflash chromatography (30-40% ethyl acetate in hexane) to obtain 7-chloro-6-fluoro-5-(1-hydroxypropyl)-3,3-dimethylindorin-2-one (0.85 g, 44%) as a liquid. MS(ESI): m / z 272.2[M+1] + .

[0156] Step 7. Dess Martin periodinane (5.308 mg, 12.51 mmol) was added at temperature to a stirred solution of compound 7-chloro-6-fluoro-5-(1-hydroxypropyl)-3,3-dimethylindorin-2-one (1.7 g, 6.25 mmol) in dichloromethane (50 mL), and the mixture was then stirred at room temperature for 16 hours. The reaction mixture was filtered through a Celite bed and washed with ethyl acetate. The filtrate was concentrated under reduced pressure to obtain the crude compound, which was purified by combiflash column chromatography (40-50% ethyl acetate in hexane) to obtain 7-chloro-6-fluoro-3,3-dimethyl-5-propionylindorin-2-one (0.5 g, 30%) as a liquid. MS(ESI): m / z 270.2[M+1] + .

[0157] Step 8. To a stirred solution of 7-chloro-6-fluoro-3,3-dimethyl-5-propionylindorin-2-one (500 mg, 0.37 mmol) in tetrahydrofuran (20 mL), n-bromosuccinimide (660 mg, 3.71 mmol) was added in small amounts at room temperature and stirred for 16 hours. The reaction mixture was poured into ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (20-30% ethyl acetate in hexane) to obtain 5-(2-bromopropanoyl)-7-chloro-6-fluoro-3,3-dimethylindorin-2-one (0.6 g, 92%) as a yellow solid. MS(ESI): m / z 348.2[M+1] + .

[0158] Step 9. To a stirred solution of DMSO (7 mL), tert-butoxide potassium (251 mg, 2.24 mmol) was added in three small amounts at room temperature and stirred for 20 minutes. A solution of diethyl malonate (238 mg, 3.75 mmol) in DMSO (1 mL) was added to the reaction mixture and stirred for 20 minutes. A solution of 5-(2-bromopropanoyl)-7-chloro-6-fluoro-3,3-dimethylindorin-2-one (600 mg, 1.72 mmol) in DMSO (2 mL) was added to the reaction mixture and stirred for 3 hours. After the reaction was complete, the mixture was quenched with acetic acid (176 mg, 2.93 mmol). The reaction mixture was diluted with water and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude mass was purified by combiflash column chromatography (5-10% ethyl acetate in hexane) to obtain diethyl 2-(1-(7-chloro-6-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-1-oxopropan-2-yl)malonate (0.24 g, 33%) as an off-white solid. MS(ESI): m / z 428.2[M+1] + .

[0159] Step 10.1,4-Dioxane (3 mL) was mixed with a stirred solution of compound 1 (240.0 mg, 0.56 mmol). Concentrated hydrochloric acid (7.0 mL, 6 N) was added at room temperature, and the mixture was stirred at 90°C for 16 hours. The reaction mixture was diluted with ice water and extracted with ethyl acetate. The combined organic layer was concentrated under reduced pressure to obtain 4-(7-chloro-6-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-3-methyl-4-oxobutanoic acid (200 mg, crude), which was then used to proceed to the next step. MS(ESI): m / z 328.2[M+1] + .

[0160] Step 11. To a stirred solution of 4-(7-chloro-6-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-3-methyl-4-oxobutanoic acid (200.0 mg, 0.61 mmol) in ethanol (4 mL), hydrazine monohydrate (0.2 mL, 3.05 mmol) was added at room temperature. The reaction mixture was stirred at 80 °C for 16 hours. After completion, the reaction mixture was cooled to room temperature and concentrated under reduced pressure. The crude product was purified by reverse-phase preparative HPLC to obtain the compound of Example #36 (35.8 mg, 25% in 2 steps) as a white solid (purity 99.36%). 1H NMR (400MHz, DMSO-d6): δ11.17(s,1H),11.02(s,1H),7.50(d,J=6.8Hz,1H),3.18-3. 13(m,1H),2.72-2.66(m,1H),2.27-2.22(m,1H),1.29(s,6H),1.06(d,J=7.16Hz,3H).

[0161] Example #38: Preparation of 2-amino-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)benzo[d]thiazole-4-carbonitrile [ka] Step 1. 6-(4-amino-3-bromophenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one. This intermediate was prepared in the same manner as the intermediate in Step 1 of Example #30, but NBS was used instead of NCS. LC / MS M+H=282.

[0162] Step 2.6-(2-amino-4-bromobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one. This intermediate was prepared in the same manner as the intermediate in Step 2 of Example #30. LC / MS M+H=339.

[0163] Step 3. A mixture of 6-(2-amino-4-bromobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one (100 mg, 0.3 mmol), Zn(CN)2 (42 mg, 0.35 mmol), and Pd(dppf)Cl2 (22 mg, 0.03 mmol) in DMF (4 mL) was heated to 150 °C for 2 hours under microwave irradiation. The reaction mixture was then cooled, extracted with siRNA:MeOH (100 mL, 95:5), and washed with water. The organic phase was dried (Na2SO4), concentrated under reduced pressure, and the crude product was purified over 20 minutes using reverse-phase chromatography, eluting from 95:5:0.1 water:MeCN:TFA to 75:25:0.1 MeCN:water:TFA, to obtain the compound of Example #38 (15 mg, 13%) as a solid. 1H NMR (400MHz, DMSO-d6): δ11.0(s,1H), 8.40-8.36(m,3H), 7.98(s,1H), 3.43(q,1H), 2.73-2.68(m,1H), 2.24(d,1H), 1.08(d,3H).

[0164] Example #40 Preparation of (6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2-oxo-1,2-dihydroquinoline-8-carbonitrile) [ka] Step 1. To a solution of 3,4-dihydroquinoline-2(1H)-one (1.0 g, 6.8 mmol) in 1,2-dichloroethane (20 mL), 2-chloropropanoyl chloride (1.27 g, 10.2 mmol) was added in three equal parts, with aluminum trichloride (3.6 g, 27 mmol) added over 15 minutes. The mixture was heated at 60°C in a nitrogen atmosphere for 5 hours. The reaction mixture was cooled to room temperature and poured into ice water (100 mL). Volatile substances were removed by rotary evaporation at low pressure, forming a precipitate. The precipitate was collected by suction filtration and washed with water (2 × 25 mL). Upon drying, 0.8 g of the crude product 6-(2-chloropropanoyl)-3,4-dihydroquinoline-2(1H)-one was weighed and used directly in the next step.

[0165] Step 2. 6-(2-chloropropanoyl)-3,4-dihydroquinoline-2(1H)-one (0.80 g, 3.4 mmol) was dissolved in DMF (5 mL), and NBS (1.2 g, 6.8 mmol) was added. The solution was heated at 80°C for 12 hours. The reaction mixture was poured into ice water (50 mL), and the precipitate was collected by suction filtration. The precipitate was washed with water (3 × 20 mL), dried, and the product, 8-bromo-6-(2-chloropropanoyl)-3,4-dihydroquinoline-2(1H)-one (0.94 g, 3.0 mmol).

[0166] Step 3. To a solution of 8-bromo-6-(2-chloropropanoyl)-3,4-dihydroquinoline-2(1H)-one (0.94 g, 3.0 mmol) and NBS (0.67 g, 3.8 mmol), benzoyl peroxide (catalytic amount) was added. The mixture was refluxed for 5 hours. The volatiles were evaporated, and the residual solid was partitioned between water (25 mL) and ethyl acetate (50 mL). The organic phase was washed with water (25 mL), dried, and concentrated. The product, 8-bromo-6-(2-chloropropanoyl)-3,4-dihydroquinoline-2(1H)-one (0.54 g, 1.7 mmol), was obtained after flash column chromatography using a gradient of ethyl acetate in hexane.

[0167] Step 4. t-BuOK (280 mg, 2.5 mmol) was added to anhydrous DMSO (15 mL) under an N2 atmosphere. The mixture was stirred at 30°C for 30 minutes. Diethyl malonate (410 mg, 2.5 mmol) was diluted with DMSO (5 mL) and added dropwise to the stirred mixture over a period of 1 hour. The reaction solution was stirred at 30°C for a further 1 hour. 8-Bromo-6-(2-chloropropanoyl)-3,4-dihydroquinoline-2(1H)-one (540 mg, 1.7 mmol) was added to the reaction mixture in three portions over 15 minutes. The reaction mixture was then stirred at 40°C for 2 hours. The reaction mixture was cooled to room temperature and quenched with acetic acid (2 mL). Water (50 mL) and methylene chloride (30 mL) were added to the reaction mixture in a separatory funnel. Each layer was mixed and divided. The organic phase was collected and washed with brine (3 × 20 mL). The organic phase was dried over sodium sulfate and concentrated to obtain the crude product, diethyl 2-(1-(8-bromo-2-oxo-1,2-dihydroquinoline-6-yl)-1-oxopropan-2-yl)malonate, which was used directly in the next step.

[0168] Step 5.2-(1-(8-bromo-2-oxo-1,2-dihydroquinoline-6-yl)-1-oxopropan-2-yl)malonate (1.7 mmol) was suspended in a 1:1 solution of dioxane / water (10 mL). Sodium hydroxide (0.340 g, 8.5 mmol) was added to the mixture. The mixture was heated at 60 °C for 12 hours. The reaction mixture was allowed to cool to room temperature before adding AcOH (10 mmol). The reaction mixture was stirred for 10 minutes, then frozen and lyophilized to obtain a white solid mixture. The mixture was suspended in EtOH (10 mL) and hydrazine monohydrate (0.175 g, 3.5 mmol) was added to the mixture. The reaction mixture was heated at 65 °C overnight. The reaction mixture was allowed to cool to room temperature. The volatile components were evaporated using rotary evaporation at low pressure to obtain a white solid. Water (20 mL) was added to the solid, and the insoluble substance was filtered out to obtain the crude product as a brown solid (0.21 g). Purification by reverse-phase HPLC yielded the pure product, 8-bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)quinoline-2(1H)-one (171 mg, 0.51 mmol).

[0169] Step 6. 8-Bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)quinolin-2(1H)-one (171 mg, 0.51 mmol), Zn(CN)2 (117 mg, 1.0 mmol), Pd2(dba)3 (47 mg, 0.051 mmol) and zinc powder (32 mg, 0.5 mmol) were added to a three-neck round-bottom flask, followed by the addition of DMF (10 mL). Nitrogen gas was bubbled through the reaction mixture for 10 minutes. P(tBu)3 (100 mg, 0.025 mmol) was added as a hexane solution (1 mg). Then, the reaction mixture was stirred at 50 °C for 5 hours under a nitrogen atmosphere. The reaction mixture was cooled to room temperature and 30 mL of ice water was added with stirring. The precipitate was collected by suction filtration and purified by reverse-phase HPLC to give the compound of Example #40 (8 mg, 0.029 mmol) as a beige solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 1.10 (d, J = 7.34 Hz, 3H) 2.11 - 2.35 (m, 1H) 2.61 - 2.86 (m, 2H) 3.34 - 3.61 (m, 1H) 6.73 (br s, 1H) 8.34 (br s, 1H) 8.43 (br s, 1H) 11.11 (s, 1H) 11.81 (br s, 1H).

[0170] Example #40 exists as the following tautomer, 2-hydroxy-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)quinoline-8-carbonitrile (#40a):

Chem.

[0171] Preparation of Example #41 (7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2,3-dihydro-1H-isoindol-1-one)

Chem.

[0172] Step 2. A solution of 1,3-diethyl 2-[1-(7-chloro-3,3-dimethyl-1-oxo-2,3-dihydro-1H-isoindole-5-yl)-1-oxopropan-2-yl]propanedioate (130 mg, 0.318 mmol) in 5 mL of 6 N hydrochloric acid aqueous solution was heated at 90°C for 16 hours. After completion, volatile matter was removed under reduced pressure, and the residue was distilled twice with toluene. The crude product was pulverized with diethyl ether to obtain 4-(7-chloro-3,3-dimethyl-1-oxo-2,3-dihydro-1H-isoindole-5-yl)-3-methyl-4-oxobutanoic acid (90 mg, crude product) as a brown gum, which was then removed without further purification and proceeded to the next step. MS(ESI): m / z 310.1[M+1]+.

[0173] Step 3. Hydrazine monohydrate (0.06 ml, 1.16 mmol) was added to a stirred solution of 4-(7-chloro-3,3-dimethyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl)-3-methyl-4-oxobutanoic acid (90 mg, 0.29 mmol) in ethanol (5 mL) at room temperature. The resulting mixture was heated at 90 °C for 16 h. After completion, the volatiles were removed under reduced pressure and the resulting crude product was purified by reverse phase preparative HPLC to give the compound of Example #41 (12 mg) as an off-white solid (97.52% purity). 1H NMR (400 MHz, DMSO-d6): δ 11.15 (s, 1H), 8.82 (s, 1H), 7.95 (s, 1H), 7.77 (s, 1H), 3.51 - 3.48 (m, 1H), 2.78 - 2.72 (m, 1H), 2.32 - 2.25 (m, 1H), 1.46 (s, 6H), 1.08 (d, J = 7.2 Hz, 3H).

[0174] Preparation of Example #42 (4-chloro-1-methyl-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1,3-dihydro-2H-benzo[d]imidazol-2-one)

Chemical Structure

[0175] Step 2. At 0°C, ammonium formate (6.8 g, 107.53 mmol) was added to a stirred solution of 3-chloro-N-methyl-2-nitroaniline (2.0 g, 10.75 mmol) in methanol (30 mL), and the mixture was stirred at 0°C for 20 minutes. Zinc dust (7.1 g, 107.53 mmol) was added to the reaction mixture in small amounts at 0°C, and the mixture was stirred at room temperature for 16 hours. After completion, the reaction mixture was filtered, washed with ethyl acetate, and the combined filtrate was evaporated under reduced pressure. The residue was diluted with water and extracted twice with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (40-60% Â in hexane) and 3-chloro-N 1 Methylbenzene-1,2-diamine (3.95 g, 67%) was obtained as an off-white solid. MS(ESI): m / z 157.0[M+1] + .

[0176] Step 3. 3-chloro-N in dichloromethane (10 mL) 1 Triethylamine (1.39 mL, 10.0 mmol) was added at 0°C to a stirred solution of methylbenzene-1,2-diamine (1.3 g, 8.33 mmol). Triphosgene (3.71 g, 12.5 mmol) was added in small amounts under cooling conditions. The reaction mixture was allowed to reach room temperature and stirred for 5 hours. After completion, volatiles were removed under reduced pressure, the residue was diluted with water, and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (30-50% Â in hexane) to obtain 4-chloro-1-methyl-1,3-dihydro-2H-benzo[d]imidazole-2-one (0.5 g, 31%) as an off-white solid. MS(ESI): m / z 183.0[M+1] + .

[0177] Step 4. A slurry of aluminum chloride (7.33 g, 54.95 mmol) and DMF (1.41 mL, 18.13 mmol) was heated at 80°C for 15 minutes. The resulting mixture was cooled to room temperature, and 4-chloro-1-methyl-1,3-dihydro-2H-benzo[d]imidazole-2-one (1 g, 5.5 mmol) was added in small amounts while maintaining the temperature below 40°C. 2-chloropropanoyl chloride (0.52 mL, 6.87 mmol) was added dropwise, and the mixture was stirred at 80°C for 2 hours. After completion, the reaction mixture was poured into ice water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (40-60% siRNA in hexane) to obtain 4-chloro-6-(2-chloropropanoyl)-1-methyl-1,3-dihydro-2H-benzo[d]imidazole-2-one (0.19 g, 11%) as a white solid. MS(ESI): m / z 273.0[M+1] + .

[0178] Step 5. To a stirred solution of tert-butoxide potassium (3.09 g, 27.57 mmol) in DMSO (30 mL), a solution of diethyl malonate (4.41 g, 27.57 mmol) in DMSO (25 mL) was added dropwise over 10 minutes, and the mixture was stirred at room temperature for 40 minutes. A solution of 4-chloro-6-(2-chloropropanoyl)-1-methyl-1,3-dihydro-2H-benzo[d]imidazole-2-one (5 g, 18.38 mmol) in DMSO (25 mL) was added dropwise over 10 minutes at 0°C under an argon atmosphere. The resulting mixture was slowly warmed to room temperature and stirred for 3 hours. After completion, the reaction mixture was quenched with saturated ammonium chloride aqueous solution at 0°C and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (30-50% ethyl hexane) to obtain diethyl 2-(1-(7-chloro-3-methyl-2-oxo-2,3-dihydro-1H-benzo[d]imidazole-5-yl)-1-oxopropan-2-yl)malonate (3 g, 48%) as a white solid. MS(ESI): m / z 397.0[M+1] + .

[0179] Step 6. A stirred solution of diethyl 2-(1-(7-chloro-3-methyl-2-oxo-2,3-dihydro-1H-benzo[d]imidazole-5-yl)-1-oxopropan-2-yl)malonate (3 g, 7.56 mmol) in 50 mL of 6 N hydrochloric acid solution was heated at 90°C for 16 hours. After completion, volatiles were removed under reduced pressure, and the residue was distilled twice with toluene. The crude product was pulverized with diethyl ether to obtain 4-(7-chloro-3-methyl-2-oxo-2,3-dihydro-1H-benzo[d]imidazole-5-yl)-3-methyl-4-oxobutanoic acid (1.2 g, crude product) as a brown gum, which was then removed without further purification and proceeded to the next step. MS(ESI): m / z 295.0[M-1] + .

[0180] Step 7. To a stirred solution of 4-(7-chloro-3-methyl-2-oxo-2,3-dihydro-1H-benzo[d]imidazole-5-yl)-3-methyl-4-oxobutanoic acid (500.0 mg, 1.69 mmol, crude) in ethanol (20 mL), hydrazine monohydrate (0.34 ml, 6.76 mmol) was added at room temperature. The resulting mixture was heated at 90 °C for 16 hours. After completion, volatiles were removed under reduced pressure, and the resulting crude product was purified by reverse-phase preparative HPLC to obtain the compound of Example #42 (18 mg, 4% in two steps) as an off-white solid (93.65% purity). 1H NMR(400MHz,DMSO-d6,100°C):δ10.63(s,1H),10.35(brs,1H),7.44-7.41(m,2H),3 .44(m,1H),3.34(s,3H),2.71-2.67(m,1H),2.33-2.2(m,1H),1.06(d,J=6.4Hz,3H).

[0181] Preparation of Example #43 (7'-fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclobutan-1,3'-indoline]-2'-one) [ka] Step 1. 7-Fluoroindolin-2-one (2.0 g, 13.2 mmol) and LiCl (1.7 g, 39.7 mmol) were added to THF (50 mL), and the mixture was cooled to -78°C. Next, n-BuLi (17.0 mL, 26.5 mmol) was slowly added, and the reaction mixture was stirred at -78°C for about 30 minutes. 1,3-Dibromopropane (2.0 mL, 19.9 mmol) was slowly added, and the reaction mixture was warmed to room temperature overnight with stirring. The reaction mixture was quenched with 0.1 N HCl (75 mL) and extracted with SiO2 (2 × 75 mL). The combined organic phase was dried to (Na2SO4) and concentrated under vacuum. The crude substance was subjected to chromatography (using an 80g Redi-Sep column) eluting from 100% hexane to 30:70 siRNA, yielding 7'-fluorospiro[cyclobutan-1,3'-indoline]-2'-one as a solid. LC / MS M+H=192.

[0182] Step 2. DMF (0.55 mL, 7.1 mmol) was added dropwise to anhydrous AlCl3 (3.3 g, 24.0 mmol), and the mixture was stirred at 70°C for about 15 minutes, then cooled to 40°C. Next, 7'-fluorospiro[cyclobutan-1,3'-indoline]-2'-one (500 mg, 1.6 mmol) and 3-methyltetrahydrofuran-2,5-dione (450 mg, 3.9 mmol) were slowly added. The reaction mixture was heated at 70°C for 2 hours, then slowly poured into ice water, filtered, and air-dried to obtain 4-(7'-fluoro-2'-oxospiro[cyclobutan-1,3'-indoline]-5'-yl)-3-methyl-4-oxobutanoic acid as a mixture of positional isomers. LC / MS M+H=306.

[0183] Step 3. To a solution of crude 4-(7'-fluoro-2'-oxo-spiro[cyclobutan-1,3'-indoline]-5'-yl)-3-methyl-4-oxo-butanoic acid (150 mg, 0.49 mmol) in EtOH (15 mL), hydrazine hydrate (0.2 mL, 1.9 mmol) was added. The reaction mixture was heated at 80°C for 18 hours. The reaction mixture was cooled in an ice bath, filtered, and washed with cold EtOH. The precipitate was dried under vacuum. The crude positional isomer mixture was purified using reverse-phase chromatography, eluting from 95:5:0.1 water:MeCN:TFA to 80:20:0.1 MeCN:water:TFA to collect minor positional isomers as the compound of Example #43. 1H NMR(400MHz,DMSO-d6):δ10.95-10.93(m,2H),7.85(s,1H),7.49(d,2H),3.46 (q,1H),2.72-2.68(m,1H),2.49-2.33(m,5H),2.29-2.15(m,3H),1.08(d,3H).

[0184] In Example #50, 7-fluoro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one was prepared in the same manner as in Example #6, but 4-(7-fluoro-2-oxoindorin-5-yl)-3-methyl-4-oxobutanoic acid was used instead of 4-(7-chloro-2-oxoindorin-5-yl)-3-methyl-4-oxobutanoic acid to obtain the compound of Example #50. ¹H NMR (400MHz, DMSO-d6): δ 11.03 (s,1H), 10.93 (s,1H), 7.51-7.47 (m,2H), 3.61 (s,2H), 3.37 (q,1H), 2.68-2.64 (m,1H), 2.22 (d,1H), 1.05 (d,3H).

[0185] In Example #74, 5-(7-fluoro-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was prepared in the same manner as in Example #57, but 7-fluoro-2,3-dihydro-1H-indole-2-one was used instead of 7-fluoro-3,3-dimethylindorin-2-one to obtain the compound of Example #74. ¹H NMR (400 MHz, DMSO-d6): δ 11.66 (s, ¹H), 11.09 (s, ¹H), 7.65 (s, ¹H), 7.55 (d, ¹H), 4.73 (q, ¹H), 1.47 (d, ³H), 1.31 (s, ⁶H).

[0186] Preparation of Example #57 (5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one) [ka] Step 1. Dimethylformamide (7.7 mL, 99.27 mmol) was added dropwise to anhydrous aluminum chloride (47.12 g, 330.91 mmol), and the mixture was stirred at 70°C for 15 minutes. The resulting mixture was cooled to 40°C, and 7-fluoro-2,3-dihydro-1H-indole-2-one (5 g, 49.64 mmol) and 2-bromopropanoyl chloride (5.1 mL, 49.64 mmol) were slowly added, and the mixture was stirred at 70°C for 2 hours. After completion, the reaction mixture was diluted with ice water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (30-40% ethyl hexane) to obtain 5-(2-bromopropanoyl)-7-fluoro-2,3-dihydro-1H-indole-2-one (3 g, 32%) as a brown solid. MS(ESI): m / z 286.1[M+1] +Alternatively, 2-chloropropanoyl chloride can be substituted for 2-bromopropanoyl chloride to produce 5-(2-chloropropanoyl)-7-fluoro-2,3-dihydro-1H-indole-2-one, and then the compound of Example 57 can be obtained in step 2.

[0187] Step 2. To a stirred solution of 5-(2-bromopropanoyl)-7-fluoro-2,3-dihydro-1H-indole-2-one (3 g, 10.53 mmol) in ethanol (30 mL), [(methoxymethane oil)amino]amine (1.12 g, 10.53 mmol) was added at room temperature under an argon atmosphere. The resulting mixture was heated at 80 °C for 16 hours. After completion, the reaction mixture was evaporated and dried, and the crude product thus obtained was purified by column chromatography (50-60% siRNA in hexane) to obtain the compound of Example #57 (1 g, 34%) as a brown solid. 1H NMR (400MHz, DMSO-d6): δ11.66 (br s, 1H), 11.10 (br s, 1H), 7.57-7.56 (m, 2H), 4.72-4.70 (m, 1H), 3.63 (s, 2H), 1.46 (d, J = 6.8Hz, 3H). LCMS: Retention time = 1.92 minutes, m / z 278.0[M-1] + HPLC purity = 97.5%. Example #78 was the (S) isomer of Example #57 and was decomposed by HPLC (column I-cellulose Z 150x4.6mm, 3μ, mobile phase (hexane / ethanol / isopropylamine (70 / 30 / 0.1), flow rate 1.0 mL / min)). The HPLC retention times for Examples #57 and #78 were 4.22 minutes and 5.11 minutes, respectively.

[0188] Example #55. The preparation of 4-methyl-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazin-5-yl)benzo[d]thiazol-2(3H)-one was carried out in the same manner as in Example #57, except that 4-methylbenzo[d]thiazol-2(3H)-one was used instead of 7-fluoro-2,3-dihydro-1H-indol-2-one to obtain the compound of Example #55. 1H NMR (400 MHz, DMSO-d6): δ 11.93 (s, 1H), 11.62 (s, 1H), 7.83 (s, 1H), 7.55 (s, 1H), 4.72 - 4.66 (m, 1H), 2.36 (s, 3H), 1.47 (d, J = 7.2, 3H).

[0189] Example #56. The preparation of 4-chloro-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazin-5-yl)benzo[d]thiazol-2(3H)-one was carried out in the same manner as in Example #57, except that 4-chlorobenzo[d]thiazol-2(3H)-one was used instead of 7-fluoro-2,3-dihydro-1H-indol-2-one to obtain the compound of Example #56. 1H NMR (400 MHz, DMSO-d6): δ 12.47 (s, 1H), 11.76 (s, 1H), 8.04 (d, J = 1.6 Hz, 1H), 7.77 (d, J = 1.6 Hz, 1H), 4.75 - 4.70 (m, 1H), 1.47 (d, J = 7.2 Hz, 3H).

[0190] In Example #58, 5-(7'-chloro-2'-oxospiro[cyclopropan-1,3'-indoline]-5'-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was prepared in the same manner as in Example #57, but 7'-chlorospiro[cyclopropan-1,3'-indoline]-2'-one was used instead of 7-fluoro-2,3-dihydro-1H-indole-2-one to obtain the compound of Example #58. 1H NMR(400MHz,DMSO-d6):δ11.65(s,1H),11.25(s,1H),7.67(s,1H),7.40(s,1H),4 .75-4.69(m,1H),1.75-1.70(m,2H),1.56(d,J=4.2Hz,2H),1.45(d,J=7.1Hz,3H).

[0191] In Example #65, 5-(8-bromo-2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was prepared in the same manner as in Example #57, but 8-bromo-3,4-dihydroquinolone was used instead of 7-fluoro-2,3-dihydro-1H-indole-2-one to obtain the compound of Example #65. ¹H NMR (400 MHz, chloroform-d) δ ppm 8.75 (s, ¹H), 7.89 (br s ¹H), 7.71 (d, ¹H), 7.46 (s, ¹H), 4.12 (d, ¹H), 2.98 (m, ²H), 2.61 (dd, ²H), 1.59 (d, ³H).

[0192] In Example #67, (6R)-5-(8-chloro-4,4-dimethyl-2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was prepared in the same manner as in Example #57, but 8-chloro-4,4-dimethyl-3,4-dihydroquinoline-2(1H)-one was used instead of 7-fluoro-2,3-dihydro-1H-indole-2-one to obtain the compound of Example #67. 1H NMR (400MHz, DMSO-d6): δ11.68 (brs, 1H), 9.81 (brs, 1H), 7.73 (brs, 2H), 4.81 (brs, 1H), 2.47 (s, 2H), 1.45 (d, J = 6.4Hz, 3H), 1.28 (brs, 6H).

[0193] In Example #75, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was prepared in the same manner as in Example #57, but 7-chloro-3,3-dimethylindorin-2-one was used instead of 7-fluoro-2,3-dihydro-1H-indole-2-one to obtain the compound of Example #75. ¹H NMR (400MHz, DMSO-d6): δ 11.66 (s, ¹H), 11.02 (s, ¹H), 7.74 (s, ¹H), 7.68 (s, ¹H), 4.76-4.73 (m, ¹H), 1.47 (d, J=6.8Hz, ³H), 1.31 (s, ⁶H).

[0194] In Example #76, 5-(7-bromo-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was prepared in the same manner as in Example #57, but 7-bromo-3,3-dimethylindorin-2-one was used instead of 7-fluoro-2,3-dihydro-1H-indole-2-one to obtain the compound of Example #76. ¹H NMR (400MHz, DMSO-d6): δ 11.66 (s, 1H), 10.91 (s, 1H), 7.80 (d, J=1.3, 1H), 7.77 (d, J=1.2, 1H), 4.78-4.73 (m, 1H), 1.47 (d, J=7.1Hz, 3H), 1.30 (s, 6H).

[0195] Preparation of Example #61 (5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one) [ka] Step 1. Dimethylformamide (0.5 mL, 7.66 mmol) was added dropwise to anhydrous aluminum chloride (3.41 g, 25.55 mmol), and the mixture was stirred at 70°C for 15 minutes. The resulting mixture was cooled to 40°C, and 7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (500 mg, 2.55 mmol) and 2-chloroacetyl chloride (0.26 ml, 3.32 mmol) were slowly added, and the mixture was stirred at 70°C for 2 hours. After completion, the reaction mixture was diluted with ice water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (40-50% siRNA in hexane) to obtain 7-chloro-5-(2-chloroacetyl)-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (300 mg, 43%) as a yellow solid. MS(ESI): m / z 269.8[M-1] + .

[0196] Step 2. To a stirred solution of 7-chloro-5-(2-chloroacetyl)-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (300 mg, 1.1 mmol) in acetonitrile (10 mL), [(methoxymethane-thiol)amino]amine (117 mg, 1.1 mmol) was added, and the reaction mixture was stirred at room temperature for 5 minutes. AcOH (0.1 mL) was added, and the resulting mixture was heated at 80 °C for 16 hours. The reaction mixture was cooled to room temperature, and volatiles were removed under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (60-70% ethyl hexane) to obtain the compound of Example #61 (120 mg, 35%) as an off-white solid. 1H NMR (400MHz, DMSO-d6): δ11.56(s,1H), 11.03(s,1H), 7.74(s,1H), 7.70(s,1H), 4.21(s,2H), 1.30(s,6H). LCMS: retention time = 2.48 min, HPLC purity = 98.56%

[0197] In Example #59, 5-(7-fluoro-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was prepared in the same manner as in Example #61, but 7-fluoro-3,3-dimethylindorin-2-one was used instead of 7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one to obtain the compound of Example #59. ¹H NMR (400MHz, DMSO-d6): δ 11.56 (s, 1H), 11.09 (s, 1H), 7.65 (s, 1H), 7.56 (dd, J=0.8Hz, 11.8Hz, 1H), 4.20 (s, 2H), 1.30 (s, 6H).

[0198] In Example #66, 5-(7-bromo-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was prepared in the same manner as in Example #61, but 7-bromo-3,3-dimethylindorin-2-one was used instead of 7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one to obtain the compound of Example #66. ¹H NMR (400 MHz, DMSO-d6): δ 11.57 (s, ¹H), 10.91 (s, ¹H), 7.82 (s, ¹H), 7.77 (s, ¹H), 4.21 (s, ²H), 1.30 (s, ⁶H).

[0199] In Example #72, 5-(2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one was prepared in the same manner as in Example #61, but 1,3,4,5-tetrahydro-2H-benzo[b]azepine-2-one was used instead of 7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one to obtain the compound of Example #72. ¹H NMR (400 MHz, DMSO-d6): δ 11.57 (s, ¹H), 9.72 (s, ¹H), 7.76-7.64 (m, ²H), 7.03 (d, ¹H), 4.21 (s, ²H), 2.73 (br t, ²H), 2.16 (br m, ²H).

[0200] Preparation of Example #62 (5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one) [ka] Step 1. Dimethylformamide (3.05 mL, 39.52 mmol) was added dropwise to anhydrous aluminum chloride (16 g, 119.76 mmol), and the mixture was stirred at 70°C for 15 minutes. The resulting mixture was cooled to 40°C, and 7-chloro-2,3-dihydro-1H-indole-2-one (2 g, 11.97 mmol) and 2-chloropropanoyl chloride (1.3 mL, 15.56 mmol) were slowly added, and the mixture was stirred at 70°C for 2 hours. After completion, the reaction mixture was diluted with ice water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (30-40% ethyl hexane) to obtain 7-chloro-5-(2-chloropropanoyl)-2,3-dihydro-1H-indole-2-one (900 mg, 29%) as a brown solid. MS(ESI): m / z 257.9[M+1] + .

[0201] Step 2. To a stirred solution of 7-chloro-5-(2-chloropropanoyl)-2,3-dihydro-1H-indole-2-one (500 mg, 1.76 mmol) in acetonitrile (10 mL), [(methoxymethane oil)-amino]amine (186.18 mg, 1.76 mmol) was added, and the resulting mixture was stirred at room temperature for 5 minutes. Acetic acid (0.1 mL) was added, and the reaction mixture was heated at 80 °C for 4 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (50-60% ethyl acetate in hexane) to obtain the compound of Example #62 (150 mg, 26%) as a brown solid. 1 H NMR (400MHz, DMSO-d6): δ11.66(brs,1H),11.03(brs,1H),7.68(s,1H),7.65(s,1H),4.75-4.70(m,1H),3.66(s,2H),1.45(d,J=6.8Hz,3H). LCMS: retention time = 2.01 min, HPLC purity = 98.46%

[0202] Example #73 Preparation of (6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one) [ka] Step 1. To a stirred solution of 8-methyl-1,2,3,4-tetrahydronaphthalene-1-one (500 mg, 3.12 mmol) in methanol (10 mL), hydroxylamine hydrochloride (260 mg, 3.74 mmol) was added, followed by sodium acetate (307 mg, 3.74 mmol) under an argon atmosphere at room temperature. The resulting mixture was stirred at 60°C for 4 hours. After completion, the reaction mixture was cooled to ambient temperature, and the resulting precipitate was removed by filtration. The filtrate was concentrated under reduced pressure to obtain N-[(1E)-8-methyl-1,2,3,4-tetrahydronaphthalene-1-ylidene]-hydroxylamine (460 mg, 84%) as a yellow solid. This was used in the next step without further purification. MS(ESI): m / z 176.2[M+1] + .

[0203] Step 2. To a stirred solution of phosphoric acid (1.8 mL), phosphorus pentoxide (1.79 g, 6.31 mmol) was added, and the resulting mixture was heated at 100°C for 0.5 hours. N-[(1E)-8-methyl-1,2,3,4-tetrahydronaphthalene-1-ylidene]hydroxylamine (460 mg, 2.63 mmol) was added, and the mixture was stirred at 100°C for a further 2.5 hours. After completion, the reaction mixture was poured into ice-cold water. The solid thus formed was filtered, washed with water, and dried under reduced pressure to obtain 9-methyl-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (400 mg, 86%) as a brown solid. MS(ESI): m / z 176.2[M+1] + .

[0204] Step 3. Dimethylformamide (0.58 mL, 7.44 mmol) was added dropwise to anhydrous aluminum chloride (3.3 g, 24.81 mmol), and the mixture was stirred at 70°C for 15 minutes. The resulting mixture was cooled to 40°C, and 9-methyl-2,3,4,5-tetrahydro-1H-1-benzazepine-2-one (400 mg, 2.48 mmol) and 2-chloropropanoyl chloride (0.3 mL, 2.98 mmol) were added. The resulting mixture was heated at 70°C for 2 hours. After completion, the reaction mixture was diluted with ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (30-40% siRNA in hexane) to obtain 7-(2-chloropropanoyl)-9-methyl-2,3,4,5-tetrahydro-1H-1-benzazepine-2-one (400 mg, 66%) as a brown solid. MS(ESI): m / z 266.3[M+1] + .

[0205] Step 4. To a stirred solution of 7-(2-chloropropanoyl)-9-methyl-2,3,4,5-tetrahydro-1H-1-benzazepine-2-one (250 mg, 0.94 mmol) in acetonitrile (5 mL), [(ethoxymethane oil)amino]amine (100 mg, 0.94 mmol) was added and stirred at room temperature for 5 minutes. AcOH (0.1 mL) was added and the resulting mixture was heated at 80 °C for 16 hours. The reaction mixture was cooled to room temperature and volatiles were removed under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (40-60% ethyl acetate in hexane) to obtain the compound of Example #73 (60 mg, 21%) as an off-white solid. 1H NMR (400MHz, DMSO-d6): δ11.64(s,1H),9.24(s,1H),7.56(s,2H),4.74-4.69(m ,1H),2.71-2.67(m,2H),2.27(s,3H),2.15-2.05(m,4H),1.48(d,J=6.8Hz,3H). LCMS: retention time = 2.47 min, HPLC purity = 96.28%.

[0206] Preparation of Example #77 (5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2-oxoindoline-7-carbonitrile) [ka] Step 1. A slurry of anhydrous AlCl3 (31.4 g, 235.8 mmol) and DMF (5.4 mL, 70.7 mmol) was heated at 70°C for 15 minutes, then cooled to 40°C. 7-Bromoindorin-2-one (5.0 g, 23.58 mmol) and 2-chloropropanoyl chloride (2.7 mL, 28.30 mmol) were slowly added. The resulting mixture was heated at 70°C for 4 hours. The reaction mixture was cooled to ambient temperature, poured onto crushed ice, and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (40-60% ethyl hexane) to obtain 7-bromo-5-(2-chloropropanoyl)indorin-2-one (4.1 g, 48%) as a brown solid. MS(ESI):m / z 302.0[M+1]+.

[0207] Step 2. To a stirred solution of 7-bromo-5-(2-chloropropanoyl)indorin-2-one (1.0 g, 3.63 mmol) in acetonitrile (10.0 mL), acetic acid (2.0 mL) and O-methylhydrazine-carbothioate (0.39 g, 3.64 mmol) were added at room temperature. The resulting reaction mixture was heated at 90 °C for 16 hours. After completion, the reaction mixture was concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (60-70% ethyl hexane) to obtain 5-(7-bromo-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (1.1 g, 24%) as an off-white solid. MS(ESI): m / z 340.05[M+1]+.

[0208] Step 3. Zinc cyanide (62.3 mg, 0.53 mmol) was added at room temperature to a stirred solution of 5-(7-bromo-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (150 mg, 0.44 mmol) in DMF (4.0 mL). The reaction mixture was degassed for 5 minutes, followed by the addition of Pd2(dba)3 (12.19 mg, 0.013 mmol) and dppf (2.46 mg, 0.004 mmol). The resulting mixture was heated under microwave (MW) conditions at 140 °C for 0.5 hours. After completion, the reaction mixture was diluted with cold water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude aggregate was purified by conventional phase separation HPLC to obtain the compound of Example #77 (65 mg, 36%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d6): δ 11.73 (s, ¹H), 11.58 (bs, ¹H), 7.97 (s, ¹H), 7.95 (s, ¹H), 4.76 (q, J=8.3 Hz, ¹H), 3.64 (s, ²H), 1.46 (d, J=7.1 Hz, ³H).

[0209] Preparation of Example #79 (7-chloro-5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2,3-dihydro-1H-isoindole-1-one) [ka] Step 1. To a stirred solution of 5-bromo-7-chloro-2-(4-methoxybenzyl)isoindorin-1-one (7.5 g, 20.5 mmol) in MeOH (150 mL), DIPEA (18 ml, 101.1 mmol), followed by Pd(dppf)Cl2.DCM (1.6 g, 2.18 mmol), the resulting mixture was purged with argon for 10 minutes and heated at 90°C for 16 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (10-20% ethyl acetate in hexane) to obtain 7-chloro-2-(4-methoxybenzyl)-5-propionylisoindorin-1-one (3.2 g, 45%) as a white solid. MS(ESI): m / z 344[M+1]+.

[0210] Step 2. To a stirred solution of 7-chloro-2-(4-methoxybenzyl)-5-propionylisoindorin-1-one (1 g, 2.89 mmol) in THF-EtOH (15 mL, 2:1 ratio), LiBH4 (158 mg, 7.22 mmol) was added and stirred at room temperature for 16 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (30-40% Â in hexane) to obtain 7-chloro-5-(hydroxymethyl)-2-(4-methoxybenzyl)isoindorin-1-one (500 mg, 54%) as an off-white solid. MS(ESI): m / z 318[M+1]+.

[0211] Step 3. To a stirred solution of 7-chloro-5-(hydroxymethyl)-2-(4-methoxybenzyl)isoindorin-1-one (1.5 g, 4.7 mmol) in DCM (25 mL), Dess Martin periodinane (3.9 g, 9.4 mmol) was added at 0°C and stirred at room temperature for 16 hours. The reaction mixture was filtered through a short Celite pad and washed with ethyl acetate. The combined filtrate was concentrated under reduced pressure and purified by combiflash column chromatography (20-30% ethyl acetate in hexane) to obtain 7-chloro-2-(4-methoxybenzyl)-1-oxoisoindorin-5-carbaldehyde (1.0 g, 67%) as an off-white solid. MS(ESI): m / z 316[M+1]+.

[0212] Step 4. To a stirred solution of 7-chloro-2-(4-methoxybenzyl)-1-oxoisoindorin-5-carbaldehyde (700 mg, 2.2 mmol) in THF (10 mL), EtMgBr (4.4 ml, 8.9 mmol, 2 M in THF) was added under ice-cold conditions and stirred at room temperature for 6 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (30-40% ethyl acetate in hexane) to obtain 7-chloro-5-(1-hydroxypropyl)-2-(4-methoxybenzyl)isoindorin-1-one (320 mg, 41%) as an off-white solid. MS(ESI): m / z 346[M+1]+.

[0213] Step 5. To a stirred solution of 7-chloro-5-(1-hydroxypropyl)-2-(4-methoxybenzyl)isoindorin-1-one (550 mg, 1.5 mmol) in DCM (15 mL), Dess Martin periodinane (1.3 g, 3.18 mmol) was added at 0°C and stirred at room temperature for 16 hours. The reaction mixture was filtered through a short Celite pad and washed with ethyl acetate. The combined filtrate was concentrated under reduced pressure and purified by combiflash column chromatography (20-30% ethyl acetate in hexane) to obtain 7-chloro-2-(4-methoxybenzyl)-5-propionylisoindorin-1-one (400 mg, 73%) as an off-white solid. MS(ESI): m / z 344[M+1]+.

[0214] Step 6. To a stirred solution of 7-chloro-2-(4-methoxybenzyl)-5-propionylisoindorin-1-one (420 mg, 1.22 mmol) in THF (10 mL), NBS (872 mg, 4.89 mmol) was added in small amounts at room temperature and stirred for 16 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (50-60% ethyl acetate in hexane) to obtain 5-(2-bromopropanoyl)-7-chloro-2-(4-methoxybenzyl)isoindorin-1-one [contaminated with dibromo-substituted compound] (280 mg, 54%) as a white solid. MS (ESI): m / z 423[M+1]+.

[0215] Step 7. A stirred solution of 5-(2-bromopropanoyl)-7-chloro-2-(4-methoxybenzyl)isoindorin-1-one (300 mg, 0.71 mmol) in TFA (5 mL) was heated at 80°C for 16 hours. After completion, volatiles were removed under reduced pressure, the residue was diluted with water, and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (70-90% Â in hexane) to obtain 5-(2-bromopropanoyl)-7-chloroisoindorin-1-one (135 mg, 63%) as an off-white solid. MS(ESI): m / z 303[M+1]+.

[0216] Step 8. To a stirred solution of 5-(2-bromopropanoyl)-7-chloroisoindorin-1-one (150 mg, 0.49 mmol) in EtOH (15 ml), O-methylhydrazine carbothioate (63 mg, 0.59 mmol) was added and heated under reflux at 90°C for 16 hours. After completion, volatiles were removed under reduced pressure, the residue was diluted with water, and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (70-90% Â in hexane) to obtain the compound of Example #79 (20.5 mg) as an off-white solid (98.22% purity). 1H NMR (400MHz, DMSO-d6): δ11.90(s,1H),8.79(s,1H),7.95(s,1H),7.84(s,1H),4.84-4.79(m,1H),4.39(s,2H),1.49(d,J=7.2Hz,3H).

[0217] Preparation of Example #80 (7-chloro-3,3-dimethyl-5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2,3-dihydro-1H-isoindole-1-one) [ka] Step 1. To a stirred solution of methyl 4-bromo-2-chloro-6-methylbenzoate (5 g, 19.09 mmol) and benzoyl peroxide (0.63 g, 3.82 mmol) in carbon tetrachloride (20 mL), NBS (4 g, 22.91 mmol) was added in small amounts at room temperature, and the resulting mixture was refluxed for 16 hours. After completion, volatile matter was removed under reduced pressure. The crude product was pulverized with pentanehexane (1:1) to obtain the desired product, 4-bromo-2-(bromomethyl)-6-chlorobenzoate (5 g, crude), as a brown solid, which was then carried out to the next step without further purification. MS(ESI): m / z 340[M+1] + .

[0218] Step 2. To a stirred solution of methyl 4-bromo-2-(bromomethyl)-6-chlorobenzoate (5 g, 14.70 mmol) and TEA (6.1 ml, 43.76 mmol) in DMF (50 mL), 4-methoxybenzylamine (3.8 mL, 29.4 mmol) was added and the mixture was stirred at room temperature for 5 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (20-30% Â in hexane) to obtain 5-bromo-7-chloro-2-(4-methoxybenzyl)isoindorin-1-one (3.3 g, 61% in 2 steps) as an off-white solid. MS(ESI): m / z 366[M+1] + .

[0219] Step 3. To a stirred solution of 5-bromo-7-chloro-2-(4-methoxybenzyl)isoindorin-1-one (1.5 g, 4.11 mmol) in THF, NaH (493 mg, 12.32 mmol, 60% of the mineral oil) was added at 0°C under an argon atmosphere, and the resulting mixture was stirred at room temperature for 30 minutes. Methyl iodide (1.0 ml, 16 mmol) was added, and the resulting mixture was heated at 70°C for 3 hours. After completion, the reaction mixture was quenched with aqueous ammonium chloride and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (10-20% ethyl acetate in hexane) to obtain 5-bromo-7-chloro-2-(4-methoxybenzyl)-3,3-dimethylisoindorin-1-one (900 mg, 56%) as a white solid. MS(ESI):m / z 394[M+1] + .

[0220] Step 4. A stirred solution of 5-bromo-7-chloro-2-(4-methoxybenzyl)-3,3-dimethylisoindolin-1-one (500 mg, 1.27 mmol) in TFA (10 mL) was heated at 80°C for 16 hours. After completion, volatiles were removed under reduced pressure, the residue was diluted with water, and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash chromatography (70-90% ethyl acetate in hexane) to obtain 5-bromo-7-chloro-3,3-dimethyl-2,3-dihydro-1H-isoindole-1-one (230 mg, 66%) as an off-white solid. MS(ESI): m / z 274[M+1] + .

[0221] Step 5. To a mixture of nBuLi (1.5 mL, 0.75 mmol, 2 M in THF) in THF (5 mL) and stirred, iPrMgCl.LiCl (0.7 mL, 0.91 mmol, 1.3 M in THF) was added under an argon atmosphere at -78°C. A solution of 5-bromo-7-chloro-3,3-dimethyl-2,3-dihydro-1H-isoindole-1-one (200 mg, 0.735 mmol) in THF (10 mL) was added to the reaction mixture, and the resulting mixture was warmed to room temperature with stirring for 1 hour. The reaction mixture was cooled to -78°C, propionaldehyde (0.32 mL, 4.41 mmol) was added, and the mixture was stirred at -78°C for 2 hours. After completion, the reaction mixture was quenched with aqueous ammonium chloride and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (40-60% siRNA in hexane) to obtain 7-chloro-5-(1-hydroxypropyl)-3,3-dimethyl-2,3-dihydro-1H-isoindole-1-one (80 mg, 43%) as a white solid. MS(ESI): m / z 254[M+1] + .

[0222] Step 6. Dess Martin periodinane (1.54 g, 3.63 mmol) was added at 0°C to a stirred solution of 7-chloro-5-(1-hydroxypropyl)-3,3-dimethyl-2,3-dihydro-1H-isoindole-1-one (460 mg, 1.82 mmol) in DCM (10 mL) and stirred at room temperature for 16 hours. The reaction mixture was filtered through a short Celite pad and washed with ethyl acetate. The combined filtrate was concentrated under reduced pressure and purified by combiflash column chromatography (50-60% siRNA in hexane) to obtain 7-chloro-3,3-dimethyl-5-propanoyl-2,3-dihydro-1H-isoindole-1-one (325 mg, 72%) as a white solid. MS(ESI): m / z 252[M+1] + .

[0223] Step 7. To a stirred solution of 5-(2-bromopropanoyl)-7-chloro-3,3-dimethyl-2,3-dihydro-1H-isoindole-1-one (150 mg, 0.60 mmol) in THF (5 mL), NBS (266 mg, 1.45 mmol) was added in small amounts at room temperature, and the resulting mixture was stirred at room temperature for 16 hours. The reaction mixture was poured into ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by combiflash column chromatography (40-60% ethyl acetate in hexane) to obtain 5-(2-bromopropanoyl)-7-chloro-3,3-dimethyl-2,3-dihydro-1H-isoindole-1-one (100 mg, 50%) as a white solid. MS(ESI): m / z 330[M+1] + .

[0224] Step 8. To a stirred solution of 5-(2-bromopropanoyl)-7-chloro-3,3-dimethyl-2,3-dihydro-1H-isoindole-1-one (250 mg, 0.76 mmol) in EtOH (10 ml), O-methylhydrazine carbothioate (97 mg, 0.912 mmol) was added and heated under reflux at 90°C for 16 hours. After completion, volatiles were removed under reduced pressure, the residue was diluted with water, and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by preparative HPLC to obtain the compound of Example #80 (35 mg, 15%) as an off-white solid (97.59% purity). 1 H NMR (400MHz, DMSO-d6): δ11.90(s,1H),8.88(s,1H),7.99(s,1H),7.81(s,1H),4.87-4.82(m,1H),1.50-1.46(m,9H).

[0225] Example #84 Preparation of (4-chloro-6-(2-oxo-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine-5-yl)benzo[d]oxazole-2(3H)-one) [ka] Step 1. Bromine (1.08 mL, 20.98 mmol) was added dropwise at 0°C to a stirred solution of 2-amino-3-chlorophenol (2 g, 13.97 mmol) in DCM (100 mL), and the resulting mixture was stirred at room temperature for 16 hours. The solid thus formed was filtered, washed with DCM, and dried. The solid residue was partitioned between saturated NaHCO3 aqueous solution and DCM. The organic layer was washed with water and brine, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 2-amino-5-bromo-3-chlorophenol (1.3 g, 41%) as a brown powder. MS(ESI): m / z 221.6[M-1] + .

[0226] Step 2. To a stirred solution of 2-amino-5-bromo-3-chlorophenol (1.3 g, 5.88 mmol) in THF (20 mL), CDI (4.58 g, 28.24 mmol) was added, and the resulting mixture was heated at 65°C for 2 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain 6-bromo-4-chloro-2,3-dihydro-1,3-benzoxazole-2-one (800 mg, 54%) as a brown powder. MS(ESI): m / z 246.0[M-1] + .

[0227] Step 3. To a stirred solution of 6-bromo-4-chloro-2,3-dihydro-1,3-benzoxazole-2-one (200 mg, 0.81 mmol) in 1,4-dioxane (4 mL) and water (1 mL), 5-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H,2H,3H-pyrrolo[2,3-b]pyridine-2-one (316 mg, 1.22 mmol), followed by K3PO4 (430 mg, 2.02 mmol), the resulting mixture was purged with argon for 10 minutes. Pd(dtbpf)Cl2 (53 mg, 0.08 mmol) was added, and the reaction mixture was heated at 100°C under microwave irradiation for 1 hour. After completion, the reaction mixture was diluted with water and extracted with 10% MeOH in DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product obtained in this manner was purified by reverse-phase preparative HPLC to obtain the compound of Example #84 (30 mg, 12%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d6): δ 12.35 (br s, ¹H), 11.10 (s, ¹H), 8.38 (s, ¹H), 7.90 (s, ¹H), 7.62 (s, ¹H), 7.53 (s, ¹H), 3.60 (s, ²H). LCMS: Retention time = 1.85 min, HPLC purity = 93.25%.

[0228] Preparation of Example #85 (5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one) [ka] For the preparation of 5-bromo-7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one, refer to steps 1-2 of Example #87. Next, to a stirred solution of 5-bromo-7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (150 mg, 0.55 mmol) in dioxane (4 mL) and water (1 mL), 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one (214 mg, 0.82 mmol), followed by K3PO4 (292 mg, 1.37 mmol), was added, and the resulting mixture was purged with argon for 10 minutes. Pd(dtbpf)Cl2 (36 mg, 0.5 mmol) was added, and the reaction mixture was heated at 100°C under microwave irradiation for 1 hour. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by column chromatography (3-10% MeOH in DCM) to obtain the compound of Example #85 (50 mg, 28%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d6): δ 11.06 (s, ¹H), 10.84 (s, ¹H), 8.37 (s, ¹H), 7.89 (s, ¹H), 7.64 (s, ¹H), 7.53 (s, ¹H), 3.60 (s, ²H), 1.32 (s, ⁶H). LCMS: Retention time = 2.42 min, HPLC purity = 96.99%

[0229] In Example #86, 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one was prepared in the same manner as in Example #85, but pyrimidine-5-boronic acid was used instead of 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one to obtain the compound of Example #86. ¹H NMR (400MHz, DMSO-d6) δ: 10.97 (br-s, 1H), 9.18-9.14 (m, 3H), 7.84 (m, 1H), 7.78 (m, 1H), 1.34 (s, 6H).

[0230] Preparation of Example #87 (6-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,4-dihydro-1,8-naphthyrizine-2(1H)-one) [ka] Step 1. To a stirred solution of 7-chloro-2,3-dihydro-1H-indole-2-one (5 g, 29.83 mmol) in dry THF (50 mL), lithium chloride (3.79 g, 89.50 mmol) was added, and the resulting mixture was cooled to -78°C. Lithium diisopropylamide (29.8 mL, 59.67 mmol, 2.0 M in THF / heptane / ethylbenzene) was added, and the mixture was stirred at -78°C for 15 minutes. Methyl iodide (3.76 mL, 59.67 mmol) was added, and the reaction mixture was stirred at room temperature for 5 hours. After completion, the reaction mixture was quenched with aqueous ammonium chloride and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by column chromatography (10-20% siRNA in hexane) to obtain 7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (2.8 g, 48%) as a yellow solid. MS(ESI): m / z 196.2[M+1] + .

[0231] Step 2. To a stirred solution of 7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (1.5 g, 7.65 mmol) in trifluoroacetic acid (15 mL), N-bromosuccinimide (892 mg, 9.18 mmol) was added in small increments, and the reaction mixture was stirred at room temperature for 16 hours. After completion, the trifluoroacetic acid was evaporated under reduced pressure. The residue was diluted with ethyl acetate, and the water and layers were separated. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (10-20% toluene in hexane) to obtain 5-bromo-7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (800 mg, 38%) as a yellow solid. MS(ESI): m / z 274.1 and 276.1 [M+1] + .

[0232] Step 3. To a stirred solution of 5-bromo-7-chloro-3,3-dimethyl-2,3-dihydro-1H-indole-2-one (500 mg, 1.83 mmol) in dioxane (5 mL), bis(pinacolate)diborone (558 mg, 2.2 mmol), followed by KOAc (360 mg, 3.66 mmol), the resulting mixture was purged with argon for 10 minutes. Pd(dppf)Cl2.dcm (150 mg, 0.183 mmol) was added, and the reaction mixture was heated at 95°C for 16 hours. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product thus obtained was purified by combiflash column chromatography (30-40% siRNA in hexane) to obtain 7-chloro-3,3-dimethyl-5-(tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3-dihydro-1H-indole-2-one (300 mg, 51%) as a brown solid. MS(ESI): m / z 322.2[M+1]+.

[0233] Step 4. To a stirred solution of 7-chloro-3,3-dimethyl-5-(tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3-dihydro-1H-indole-2-one (100 mg, 0.3 mmol) in dioxane (4 mL) and water (1 mL), 6-bromo-3,4-dihydro-1H-1,8-naphthyridine-2-one (106 mg, 0.46 mmol), followed by K3PO4 (360 mg, 3.66 mmol), the resulting mixture was purged with argon for 10 minutes. Pd(dtbpf)Cl2 (150 mg, 0.183 mmol) was added, and the reaction mixture was heated at 100°C under microwave irradiation for 1 hour. After completion, the reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product obtained in this manner was purified by reverse-phase preparative HPLC to obtain the compound of Example #87 (40 mg, 38%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d6): δ 10.86 (s, ¹H), 10.54 (s, ¹H), 8.43 (s, ¹H), 7.94 (s, ¹H), 7.67 (s, ¹H), 7.58 (s, ¹H), 2.96-2.92 (m, ²H), 2.57-2.54 (m, ²H), 1.33 (s, ⁶H). LCMS: Retention time = 2.12 min, HPLC purity = 99.16%.

[0234] In Example #25, 7-chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one was prepared in the same manner as in Example #87, but 6-bromopyridazine-3(2H)-one was used instead of 6-bromo-3,4-dihydro-1H-1,8-naphthyridine-2-one to obtain the compound of Example #25. ¹H NMR (400 MHz, DMSO-d6): δ 8.06 (d, ¹H), 7.80 (s, ¹H), 7.75 (s, ¹H), 6.98 (d, ¹H), 1.32 (s, ¹H).

[0235] The following are examples of compound numbers, compound names (mass ([M+1]+)), and their respective chemical structures.

[0236] Example # and name (mass): #1.8-(2-methoxypyridine-4-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one(364), #2.6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-8-(thiazole-2-yl)-3,4-dihydroquinoline-2(1H)-one(340), #3.8-Bromo-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one(336), #4.8-(2-methoxythiazole-5-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one(370), #5.5-methyl-6-(1-methyl-2-((4-(methylsulfonyl)phenyl)amino)-1H-benzo[d]imidazole-6-yl)-4,5-dihydropyridazine-3(2H)-one(412), #6.7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (278), #7.7-(4-chlorophenyl)-5-(6-oxo-1,6-dihydropyridazine-3-yl)indoline-2-one(337), #8.7'-Chloro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropane-1,3'-indoline]-2'-one(304), #9.8-(4-chlorophenyl)-6-(6-oxo-1,6-dihydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one(351), #10.6-(2-(benzo[d]thiazole-6-ylamino)-1-methyl-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(390), #11.8-Bromo-4,4-dimethyl-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one(364), #12.8-(3-fluorophenyl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one(352), #13.6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-8-(pyridine-3-yl)-3,4-dihydroquinoline-2(1H)-one(334), #14.8-(6-methoxypyridine-3-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one(364), #15.4-Methyl-6-(6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)benzo[d]thiazole-2(3H)-one(261), #16.6-(1-cyclopropyl-2-((4-(methylsulfonyl)phenyl)amino)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(438), #17.3,3-dimethyl-5-(4-methyl-6-oxo-1,6-dihydropyridazin-3-yl)-7-(thiazole-4-yl)indolin-2-one (352), #18.9-(6-methoxypyridine-3-yl)-7-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-1,3,4,5-tetrahydro-2H-benzo[b]azepine-2-one (378), #19.6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(375), #20.7-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-9-(thiazole-2-yl)-1,3,4,5-tetrahydro-2H-benzo[b]azepine-2-one (354), #21.5-methyl-6-(1-methyl-2-(phenylamino)-1H-benzo[d]imidazole-6-yl)-4,5-dihydropyridazine-3(2H)-one(334), #22.6-(2-(benzo[d]thiazole-6-yloxy)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(377), #23.7-Bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (350), #24.7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (306), #25.7-Chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indoline-2-one (289), #26.7-Fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (290), #27.7-Fluoro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indoline-2-one (274), #28.7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropane-1,3'-indoline]-2'-one(288), #29.4-Chloro-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)benzo[d]thiazole-2(3H)-one(296), #30.6-(2-amino-4-chlorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(295), #31.6-(2-amino-4-fluorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(279), #32.7-Bromo-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indoline-2-one(334), #33.(R)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one(306), #34.6-(4-fluoro-2-(methylamino)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(292), #35.8-Chloro-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)quinoline-2(1H)-one(290), #36.7-Chloro-6-fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (324), #37.6-(4-fluoro-2-(3-hydroxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(335), #38.2-Amino-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)benzo[d]thiazole-4-carbonitrile (285), #39.7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-1-one (278), #40.6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2-oxo-1,2-dihydroquinoline-8-carbonitrile (280), #41.7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-1-one (306), #42.4-Chloro-1-methyl-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1,3-dihydro-2H-benzo[d]imidazole-2-one (293), #43.7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclobutan-1,3'-indoline]-2'-one(301), #44.7-Chloro-3,3-dimethyl-5-(6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (291), #45.6-(8-bromo-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(334), #46.6-(4-fluoro-2-(((1-methyl-1H-pyrazole-4-yl)methyl)amino)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(373), #47.6-(7-chloro-3-methyl-1H-indazole-5-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(277), #48.6-(8-cyclopropyl-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(295), #49.6-(2-(3-methoxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(330), #50.7-Fluoro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one (261), #51.(S)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-2-one (305), #52.4-Chloro-6-(6-oxo-1,6-dihydropyridazine-3-yl)benzo[d]thiazole-2(3H)-one(280), #53.5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2-oxoindoline-7-carbonitrile (268), #54.(R)-7-fluoro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one(261), #55.4-Methyl-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one(293), #56.4-Chloro-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one(313), #57.5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (279), #58.5-(7'-chloro-2'-oxospiro[cyclopropane-1,3'-indoline]-5'-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(322), #59.5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (293), #60.(R)-5-(2-hydroxy-8-methylquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (287), #61.5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(310), #62.5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (294), #63.6-Methyl-5-(7-(4-(methylsulfonyl)phenyl)-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (415), #64.5-(9-chloro-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(324), #65.5-(8-bromo-2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(354), #66.5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(354), #67.(6R)-5-(8-chloro-4,4-dimethyl-2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(338), #68.5-(3,3-dimethyl-2-oxo-7-(thiazole-4-yl)indoline-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (372), #69.5-(7-bromo-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (340), #70.6-Methyl-5-(2-oxo-7-phenylindoline-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (337), #71.5-(7-(4-chlorophenyl)-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(372), #72.5-(2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(275), #73.6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(304), #74.5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (307), #75.5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(324), #76.5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (368), #77.5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2-oxoindoline-7-carbonitrile (286), #78.(S)-5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (279), #79.5-(7-chloro-1-oxoisoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (296), #80.5-(7-chloro-3,3-dimethyl-1-oxoisoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(324), #81.5-(8-chloro-2-hydroxyquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (308), #82.5-(7-chloro-2,2-dioxide-1,3-dihydrobenzo[c]isothiazol-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one(332), #83.6-methyl-5-(8-methyl-2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one (289), #84.4-Chloro-6-(2-oxo-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine-5-yl)benzo[d]oxazole-2(3H)-one(300), #85.5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one(328). #86.7-Chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one (274), #87.6-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,4-dihydro-1,8-naphthyridine-2(1H)-one(340), #88.4-Chloro-6-(5-oxo-4,5-dihydro-1,3,4-thiadiazole-2-yl)benzo[d]thiazol-2(3H)-one(286), and #89.5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3,4-thiadiazole-2(3H)-one(296).

[0237] The chemical structures of each compound in Examples 1 to 89 are shown below: [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0238] The dihydropyridazinone inoderator / vasodilator pimobendan has the chemical name 6-(2-(4-methoxyphenyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one and the structure shown below. [ka]

[0239] Pimobendan is rapidly absorbed when administered orally with a bioavailability of approximately 60–65%. The tmax and elimination half-life of pimobendan are approximately 2 hours and 1.6 hours, respectively. The desmethyl metabolite has a tmax and elimination half-life of approximately 3.2 hours and 5 hours, respectively. Pimobendan acts as a positive inotropic by sensitizing calcium affinity to binding to troponin C on cardiomyocytes and inhibiting PDE3. Inhibition of PDE3 also results in both arteriovenous and venous dilation, thereby improving cardiac output without increasing myocardial oxygen consumption, and is therefore used to treat congestive heart failure following myxomatous mitral valve disease or dilated cardiomyopathy in dogs. Cardiac troponin l (cTnl) is a protein unique to the heart and is a specific and highly sensitive biomarker of myocardial injury. In healthy animals, the concentration of cardiac troponin in the blood should be substantially zero, so a significant elevation indicates some degree of myocardial injury. Monitoring the effects of candidate PDE3s on cTnIs circulating in the bloodstream can provide alerts for concerns about cardiomyocyte damage and inform safety assessments in future studies. In addition, cTnIs can be used as a prognostic biomarker due to their strong association with mortality in dogs.

[0240] Biological method: cPDE3A assay (fluorescence polarized) The canine PDE3A assay kit, containing canine PDE3A recombinant enzyme, FAM-cyclic-3',5'-AMP (20 μM), PDE3 assay buffer, binder, binder diluent, and a microtiter 96-well plate, was purchased from BPS Bioscience (San Diego, CA). The compounds were first dissolved in DMSO. The stock solution concentration was then diluted sequentially with cPDE assay buffer (10-fold stock solution) to obtain a concentration response curve starting at 10 μM (total concentration of ≥7). After serial dilution, the compound solution (0.1% final DMSO) was transferred to an assay plate (96 wells), and the remaining canine PDE3A assay reagent was dispensed using the enzyme at a final concentration of 5 pg / μL according to the BPS Bioscience® protocol (catalog number 79735). Each compound was evaluated for inhibition of canine PDE3A enzyme activity using fluorescence polarization change measurement. 50% inhibitory concentration (IC) 50 The nM was calculated and reported. Compared to current cPDE3 inhibitors of the present invention, pimobendan has a cPDE3 IC of approximately 1530 nM. 50 The compound of the present invention had a value. cPDE3 inhibition data (IC 50 The values ​​are shown in nanomolar (nM) units in Table 1.

[0241] Human iPS cell cardiomyocyte contractility assay Frozen human iCell® cardiomyocytes (FujiFilm® Cellular Dynamics Inc.) were thawed and coated with 5-6 μL of human fibronectin droplets. 7-10 × 10¹⁶ electrodes were placed in the center of each well of an Axion® Biosystems cytoview 24-well microelectrode array plate. 6Cells were plated at a density of cells / mL. Cells were maintained in culture in a humidified incubator at 37°C with 5% CO2. After culturing for at least 7 days, with maintenance medium changed every 2-3 days, cells were paced at 2 Hz for approximately 48 hours using the potential application of Axis Navigator software on an Axion® Biosystems Maestro Pro instrument, and then returned to spontaneous beating for at least 10 minutes using the contractile application (i.e., Axion® Biosystems procedure for Positive Inotropy Protocol). A 3-minute baseline recording was made before adding the test material to the plate, followed by at least 60 minutes of spontaneous beating recording, with 3-minute recordings every 10 minutes. Readings were taken at 3, 13, 23, 33, 43, and 53 minutes. The compound was dissolved in DMSO and tested at a final concentration of 30 μM and a final DMSO concentration of 0.3%. After baseline recording, the compound solution was transferred to the cell plate on the instrument. Each compound was evaluated for its contractile response compared to the vehicle control (DMSO). Statistically significant changes in contractility at the final time point (53 minutes), defined by the change in mean % delta beat amplitude, are indicated with a "+" in Table 1. Changes in contractility at the final time point that were not significant from the vehicle are indicated with an "*". Significance was obtained at earlier time points for these changes. [Table 1]

[0242] As can be observed in Table 1, the compounds of the present invention have a much higher affinity for cPDE3 than other known cPDE3 inhibitors. On average, the compounds of the present invention have an IC50 affinity for the cPDE3 receptor that is approximately 57 times higher than that of pimobendan (1530 / 27). 50 It has a binding affinity of 27.1 nM (2408 / 89). In Examples 19, 57, 61, 62 and 73, the average cPDE3 IC 50 The value is approximately 13.5, which is about 113 times larger than that of pimobendane. In Examples 23, 24, 74, 75, and 76, compounds with longer terminal half-lives showed an average cPDE3 IC5.50 Its concentration is approximately 10.5 nM, which is about 129 times greater than that of pimobendan. Therefore, a low dose of any one of the compounds of the present invention can result in increased levels of cPDE3 inhibition and c-AMP, as well as a subsequent inotropic effect, thereby promoting myocardial contraction and smooth muscle dilation. As potent inotropes, the compounds of the present invention can be useful in the treatment of CHF, MMVD, and / or asymptomatic heart failure in animals, particularly dogs.

[0243] Myocardial contractility describes the innate ability of the heart muscle to contract. The ability to produce changes in force during contraction is due to the degree of binding between different types of tissues, namely, between myosin filaments and actin tissues. Contractility is an inherent property of these myocardial fibers. The degree of binding depends on the intracellular calcium ion concentration and the responsiveness of the muscle fibers to calcium. In an intact heart in vivo, the action / response of the sympathetic nervous system is driven by the precisely timed release of catecholamines, a process that determines the concentration of calcium ions in the cytoplasm of myocardial cells. Intracellular calcium ions (Ca) during contraction 2+ Factors that cause an increase in contractile work by causing an increase in ) . A measurable relative increase in contractility is a myocardial property similar to the term "inotropy". Contractility can be iatrogenically altered by the administration of inotropes. Drugs that positively render the effects of catecholamines such as norepinephrine, epinephrine, and pimobendan, which increase contractility, are considered to have a positive inotropic effect. As such, an increase in contractility generally results in an increase in cardiac output. Human cardiomyocytes that are chronically paced (2 Hz) for several days can be synchronized and the contractile or pharmacologically induced impedance changes can be measured. A dose of pimobendan increases the contractility of cardiomyocytes as defined by the change in mean % delta beat amplitude. Further contraction leads to an increase in left ventricular pressure. The cardiomyocyte contractility of the compounds of the present invention, as defined by the change in mean delta beat amplitude, was determined to have a positive inotropic effect (i.e., stronger myocardial contractility).

[0244] Furthermore, Example #57 (30 μM) was tested in a contractile amplitude (CA) assay using adult human primary ventricular cardiomyocytes dissected from the heart of a human donor, and single (PDE3 Ca) was found. 2+ Sensitization or inhibition) or double (Ca of PDE3) 2+ The potential of compounds to exert a positive inotropic effect was determined by their mechanisms of action (sensitization and inhibition). Cardiomyocytes were incubated at 35°C under continuous perfusion (2 mL / min) of 0.1% DMSO in a buffer (vehicle) solution (HEPES (10 mM), NaCl (145 mM), KCl (4 mM), MgCl2 (1 mM), CaCl2 (1.8 mM), and dextrose (11.1 mM)) in addition to cardiomyocytes. Cells were equilibrated for a minimum of 5 minutes and stimulated at 1.0 Hz with a 1.5-fold increase in stimulation intensity. A 100 μM IMBX (3-isobutyl-1-methylxanthine) nonselective inhibitor of PDE was used. The treatment time and stimulation duration were 300 seconds at 1.0 Hz. Data were collected using MyoBLAZER® (v2.9.2) software. Equilibrated cells (n=12) were stimulated with an ultrathreshold voltage at a pacing frequency of 1 Hz (bipolar pulse with a duration of 3 ms). The amplitude of the stimulation pulse was increased from 1 V until the cardiomyocytes began to generate contraction-relaxation cycles. Contractility amplitude was calculated from the average of the last 20 contractility transients. The contractility amplitudes for the vehicle, IBMX, and IBMX in Example #57 were 100, 136.8, and 267.6, respectively. The differences in CA between the vehicle and IBMX, between the vehicle and IBMX + Example #57, and between IBMX and IBMX + Example #57 were significantly different. IBMX increased CA by inhibiting PDE, but there was an even greater increase in CA in the presence of Example #57. Furthermore, the potential of Example #57 was evaluated using a CA assay, and the calcium concentration EC 50 This changed the EC of cardiomyocytes without Example #57. 50 The concentration is 1286 μM, and the EC of Example #57 50The concentration was 821 μM. From this second CA test, muscle cell contractility was dose-dependent on calcium concentration. Contractility at 100 μM, 1000 μM, and 10,000 μM CaCl2 was 3.11, 56.31, and 228.61, respectively. Addition of 30 μM of Example #57 increased the respective contractility values ​​to 40.17, 182.67, and 284.27. Overall, these contractility studies clearly demonstrate an additive effect of calcium sensitization, independent of PDE3 inhibition, thereby supporting biphasic cardiac activity.

[0245] Finally, the plasma half-lives of several compounds in dogs were evaluated. Beagle dogs were given an oral dose of each compound (0.1 mg / kg), representing a total dose of approximately 1 mg / dog. Pimopendan was administered at a dose of 0.3 mg / kg. Plasma samples were collected over 72 hours, and the plasma half-lives were calculated. The plasma half-lives (t1 / 2) in dogs are shown in Table 2 in hours. [Table 2]

[0246] As can be observed in Table 2, the compounds of the present invention have a much longer half-life than pimobendan. Therefore, the compounds of the present invention enable administration once daily (in contrast to twice daily as with pimobendan), or even once every few days (e.g., twice a week).

[0247] NT-proBNP is a standard circulating biomarker in canine MMVD, secreted by ventricular cardiomyocytes in response to stretching from volumetric or pressure overload. It is a well-defined diagnostic and prognostic biological indicator of myocardial wall stress and can be used as a biomarker for acute changes in left ventricular load conditions. In several in-house studies, NT-proBNP has been evaluated as a biomarker showing a 30% decrease in NT-proBNP, which has been associated by others to indicate reduced cardiac wall stress and improved quality of life. In one case, Example #26 reduced NT-proBNP levels by 49% and 62% over 12 hours at doses of 0.03 and 0.1 mg / kg, respectively. In contrast, a labeled dose of pimobendan reduced NT-proBNP by 41% after 24 hours. This positive pharmacological effect suggests a clinically relevant reduction in myocardial stress and therefore may slow the progression of cardiac disease.

Claims

1. below: 8-(2-methoxypyridine-4-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one, 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-8-(thiazole-2-yl)-3,4-dihydroquinoline-2(1H)-one, 8-(2-methoxythiazole-5-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one, 7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-(4-chlorophenyl)-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one, 7'-Chloro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropan-1,3'-indoline]-2'-one, 8-(4-chlorophenyl)-6-(6-oxo-1,6-dihydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one, 8-(3-fluorophenyl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one, 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-8-(pyridine-3-yl)-3,4-dihydroquinoline-2(1H)-one, 3,3-dimethyl-5-(4-methyl-6-oxo-1,6-dihydropyridazin-3-yl)-7-(thiazole-4-yl)indorin-2-one, 9-(6-methoxypyridine-3-yl)-7-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-1,3,4,5-tetrahydro-2H-benzo[b]azepine-2-one, 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one, 7-Fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Fluoro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one, 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropan-1,3'-indoline]-2'-one, 7-Chloro-3,3-dimethyl-5-(6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one, 4-Chloro-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)benzo[d]thiazole-2(3H)-one, 6-(2-amino-4-chlorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 6-(2-amino-4-fluorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-bromo-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one, (R)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 6-(4-fluoro-2-(methylamino)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 8-Chloro-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)quinoline-2(1H)-one, 6-(8-chloro-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-Chloro-6-fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 6-(4-fluoro-2-(3-hydroxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 2-amino-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)benzo[d]thiazole-4-carbonitrile, 7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-1-one, 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2-oxo-1,2-dihydroquinoline-8-carbonitrile, 2-Hydroxy-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)quinoline-8-carbonitrile, 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-1-one, 4-Chloro-1-methyl-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1,3-dihydro-2H-benzo[d]imidazole-2-one, 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclobutan-1,3'-indoline]-2'-one, 6-(8-bromo-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 6-(4-fluoro-2-(((1-methyl-1H-pyrazole-4-yl)methyl)amino)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 6-(7-chloro-3-methyl-1H-indazole-5-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 6-(8-cyclopropyl-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 6-(2-(3-methoxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-Fluoro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, (S)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-2-one, 4-Chloro-6-(6-oxo-1,6-dihydropyridazine-3-yl)benzo[d]thiazole-2(3H)-one, 5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2-oxoindoline-7-carbonitrile, 4-methyl-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one, 4-Chloro-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one, 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7'-chloro-2'-oxospiro[cyclopropane-1,3'-indoline]-5'-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-fluoro-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 6-methyl-5-(7-(4-(methylsulfonyl)phenyl)-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-bromo-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(3,3-dimethyl-2-oxo-7-(thiazole-4-yl)indoline-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-(4-chlorophenyl)-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-bromo-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2-oxoindoline-7-carbonitrile, (S)-5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-1-oxoisoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-1-oxoisoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(8-chloro-2-hydroxyquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-2,2-dioxide-1,3-dihydrobenzo[c]isothiazol-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 6-methyl-5-(8-methyl-2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 4-Chloro-6-(2-oxo-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine-5-yl)benzo[d]oxazole-2(3H)-one, 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one, 7-Chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one, 6-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-3,4-dihydro-1,8-naphthyridine-2(1H)-one, 4-Chloro-6-(5-oxo-4,5-dihydro-1,3,4-thiadiazole-2-yl)benzo[d]thiazol-2(3H)-one, and Compounds selected from the group consisting of 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3,4-thiadiazole-2(3H)-one, stereoisomers thereof, and veterinarily acceptable salts thereof.

2. 8-(2-methoxypyridine-4-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one, 8-(2-methoxythiazole-5-yl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one, 7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7'-Chloro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropan-1,3'-indoline]-2'-one, 8-(4-chlorophenyl)-6-(6-oxo-1,6-dihydropyridazine-3-yl)-3,4-dihydroquinoline-2(1H)-one, 8-(3-fluorophenyl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one, 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-8-(pyridine-3-yl)-3,4-dihydroquinoline-2(1H)-one, 9-(6-methoxypyridine-3-yl)-7-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)-1,3,4,5-tetrahydro-2H-benzo[b]azepine-2-one, 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Chloro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one, 7-Fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Fluoro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one, 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropan-1,3'-indoline]-2'-one, 7-Chloro-3,3-dimethyl-5-(6-oxo-1,4,5,6-tetrahydropyridazine-3-yl)indorin-2-one, 6-(2-amino-4-chlorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 6-(2-amino-4-fluorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-bromo-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one, (R)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 6-(4-fluoro-2-(methylamino)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 8-Chloro-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)quinoline-2(1H)-one, 6-(8-chloro-2-hydroxyquinoline-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-Chloro-6-fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 6-(4-fluoro-2-(3-hydroxyazetidine-1-yl)benzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 2-amino-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)benzo[d]thiazole-4-carbonitrile, 2-Hydroxy-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)quinoline-8-carbonitrile, 7-Chloro-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-1-one, 6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-2-oxo-1,2-dihydroquinoline-8-carbonitrile, 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)isoindorin-1-one, 4-Chloro-1-methyl-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-1,3-dihydro-2H-benzo[d]imidazole-2-one, 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclobutan-1,3'-indoline]-2'-one, 4-Chloro-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one, 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7'-chloro-2'-oxospiro[cyclopropane-1,3'-indoline]-5'-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-fluoro-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 6-methyl-5-(7-(4-(methylsulfonyl)phenyl)-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-bromo-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-(4-chlorophenyl)-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-bromo-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2-oxoindoline-7-carbonitrile, (S)-5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-1-oxoisoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-1-oxoisoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 6-methyl-5-(8-methyl-2-oxo-1,2,3,4-tetrahydroquinoline-6-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one, and A compound according to claim 1, selected from the group consisting of 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one, stereoisomers thereof, and veterinarily acceptable salts thereof.

3. 8-(3-fluorophenyl)-6-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)-3,4-dihydroquinoline-2(1H)-one, 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Fluoro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Fluoro-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one, 7'-Fluoro-5'-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)spiro[cyclopropan-1,3'-indoline]-2'-one, 6-(2-amino-4-chlorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 6-(2-amino-4-fluorobenzo[d]thiazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-bromo-3,3-dimethyl-5-(6-oxo-1,6-dihydropyridazine-3-yl)indorin-2-one, (R)-7-chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 4-Chloro-6-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)benzo[d]thiazole-2(3H)-one, 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7'-chloro-2'-oxospiro[cyclopropane-1,3'-indoline]-5'-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-bromo-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-bromo-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(6-methyl-2-oxo-3,6-dihydro-2H-1,3,4-thiadiazine-5-yl)-2-oxoindoline-7-carbonitrile, (S)-5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridine-2-one, and A compound according to claim 2, selected from the group consisting of 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one, stereoisomers thereof, and veterinarily acceptable salts thereof.

4. 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, and The compound according to claim 3, which is a compound selected from the group consisting of 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one, its stereoisomers, and veterinarily acceptable salts thereof.

5. 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, and A compound according to claim 4, selected from the group consisting of 6-methyl-5-(9-methyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-7-yl)-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, stereoisomers thereof, and veterinary-acceptable salts thereof.

6. 7-bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 5-(7-fluoro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-3,3-dimethyl-2-oxoindorin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-bromo-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, and A compound according to claim 4, selected from the group consisting of 7-chloro-3,3-dimethyl-5-(pyrimidine-5-yl)indorin-2-one, stereoisomers thereof, and veterinarily acceptable salts thereof.

7. 6-(2-(1-(4-methoxyphenyl)cyclopropyl)-1H-benzo[d]imidazole-6-yl)-5-methyl-4,5-dihydropyridazine-3(2H)-one, 7-bromo-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 7-Chloro-3,3-dimethyl-5-(4-methyl-6-oxo-1,4,5,6-tetrahydropyridazin-3-yl)indorin-2-one, 5-(7-fluoro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, 5-(7-chloro-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, and A compound according to claim 4, selected from the group consisting of 5-(7-chloro-3,3-dimethyl-2-oxoindolin-5-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazine-2-one, stereoisomers thereof, and veterinarily acceptable salts thereof.

8. A composition comprising a compound according to any one of claims 1 to 7, a stereoisomer thereof, or a veterinarily acceptable salt thereof.

9. The composition according to claim 8, comprising a compound according to any one of claims 3, 4, 5, 6, or 7, a stereoisomer thereof, or a veterinarily acceptable salt thereof.

10. The composition according to claim 8 or 9, further comprising an additional pharmaceutically active agent selected from the group consisting of an ACE inhibitor, furosemide, or spironolactone.

11. The composition according to claim 9 or 10, further comprising a veterinary-acceptable excipient.

12. A method for treating an animal having myxomatous mitral valve disease, congestive heart failure, and / or asymptomatic heart failure, comprising administering a therapeutic dose of a compound according to any one of claims 1 to 7, a stereoisomer thereof, or a veterinarily acceptable salt thereof to an animal in need.

13. The method according to claim 12, wherein the animal is administered a compound according to any one of claims 3, 4, 5, 6, or 7, a stereoisomer thereof, or a veterinarily acceptable salt thereof to an animal in need.

14. The method according to any one of claims 11 to 13, wherein the animal is administered at least one additional pharmaceutical agent selected from the group consisting of ACE inhibitors, furosemide, and spironolactone to the animal in need.

15. Use of any one of claims 1 to 7 or any one of claims 3, 4, 5, 6 or 7, a stereoisomer thereof, or a veterinarily acceptable salt thereof, for preparing a pharmaceutical for the treatment of animals requiring treatment for myxomatous mitral valve disease, congestive heart failure and / or asymptomatic heart failure.

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