Novel compound

Abstract

The present invention relates to PDE1 inhibitory compounds, and their use as medicines and the pharmaceutical compositions comprising them, which are useful for treating diseases that involve the disorder of dopamine D1 receptor intracellular pathway, such as Parkinson's disease, depression, narcolepsy, psychosis, cognitive impairment (for example, in schizophrenia), or disorders that can be alleviated by enhancing progesterone signaling pathway.Furthermore, the method of preparation and the method of use of such compounds are also described.

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present invention relates to PDE1 inhibitory compounds of formula Ia as described below, their preparation methods, their use as medicines, and pharmaceutical compositions containing them.These compounds are useful for treating diseases associated with the disorder of dopamine D1 receptor intracellular pathway, such as Parkinson's disease, depression, narcolepsy, psychosis, cognitive impairment (e.g., in schizophrenia), or disorders that can be ameliorated by enhancing progesterone signaling pathway (e.g., female sexual dysfunction). [Background technology]

[0002] 2. Background of the Invention Eleven families of phosphodiesterases (PDEs) have been identified, including Ca 2+ Only family I PDEs, calmodulin-dependent phosphodiesterases (CaM-PDEs), can bind Ca 2+ CaM-PDE1A is activated by calmodulin and has been shown to mediate calcium and cyclic nucleotide (e.g., cAMP and cGMP) signaling pathways. Thus, these PDEs become active in stimulated conditions in which intracellular calcium levels are elevated, leading to increased hydrolysis of cyclic nucleotides. The three known CaM-PDE genes, PDE1A, PDE1B and PDE1C, are all expressed in central nervous system tissues. In the brain, the primary expression of PDE1A is in the cortex and neostriatum, PDE1B is expressed in the neostriatum, prefrontal cortex, hippocampus and olfactory tubercle, and PDE1C is more ubiquitously expressed.

[0003] Cyclic nucleotide phosphodiesterases reduce intracellular cAMP and cGMP signaling by hydrolyzing these cyclic nucleotides to their respective inactive 5'-monophosphates (5'AMP and 5'GMP). CaM-PDEs play a key role in mediating signaling in brain cells, particularly within the region of the brain known as the basal ganglia or striatum. For example, NMDA-type glutamate receptor activation and / or dopamine D2 receptor activation increases intracellular calcium concentrations, activating effectors such as calmodulin-dependent kinase II (CaMKII) and calcineurin, activating CaM-PDE, and decreasing cAMP and cGMP. On the other hand, dopamine D1 receptor activation activates nucleotide cyclases, increasing cAMP and cGMP. These cyclic nucleotides then activate protein kinase A (PKA; cAMP-dependent protein kinase) and / or protein kinase G (PKG; cGMP-dependent protein kinase), which phosphorylate downstream signaling pathway elements such as DARPP-32 (dopamine and cAMP-regulated phosphoprotein) and cAMP response element binding protein (CREB). Phosphorylated DARPP-32 then inhibits the activity of phosphoprotein-1 (PP-1), thereby increasing the phosphorylation state of substrate proteins such as the progesterone receptor (PR), inducing physiological responses. Studies in rodents suggest that induction of cAMP and cGMP synthesis via activation of dopamine D1 or progesterone receptors enhances progesterone signaling, which is associated with a variety of physiological responses, including the lordosis response, which is associated with receptivity to mating in some rodents. See Mani, et al., Science (2000) 287: 1053, the contents of which are incorporated herein by reference.

[0004] Thus, CaM-PDE can affect dopamine regulatory and other intracellular signaling pathways in the basal ganglia (striatum), including, but not limited to, nitric oxide, noradrenaline, neurotensin, CCK, VIP, serotonin, glutamate (e.g., NMDA receptors, AMPA receptors), GABA, acetylcholine, adenosine (e.g., A2A receptors), cannabinoid receptors, natriuretic peptides (e.g., ANP, BNP, CNP), DARPP-32, and endorphin intracellular signaling pathways.

[0005] Phosphodiesterase (PDE) activity, especially phosphodiesterase 1 (PDE1) activity, functions as a regulator of locomotor activity and learning and memory in brain tissue.PDE1 is the therapeutic target for regulating intracellular signaling pathways, preferably in the nervous system, including but not limited to the intracellular signaling pathways of dopamine D1 receptor, dopamine D2 receptor, nitric oxide, noradrenaline, neurotensin, CCK, VIP, serotonin, glutamate (e.g., NMDA receptor, AMPA receptor), GABA, acetylcholine, adenosine (e.g., A2A receptor), cannabinoid receptor, natriuretic peptide (e.g., ANP, GNP, CNP) and endorphin, and progesterone signaling pathway.For example, inhibiting PDE1B acts to enhance the effect of dopamine D1 agonist by protecting cGMP and cAMP from degradation, and similarly inhibits dopamine D2 receptor signaling pathway by inhibiting PDE1 activity. Chronic elevation of intracellular calcium level is associated with cell death in many disorders, especially in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and Huntington's disease, and circulatory disorders that lead to stroke and myocardial infarction.Therefore, PDE1 inhibitors are potentially useful for diseases characterized by reduced dopamine D1 receptor signaling activity, such as Parkinson's disease, restless legs syndrome, depression, narcolepsy and cognitive dysfunction.PDE1 inhibitors are also useful for diseases that can be alleviated by enhancing progesterone signaling, such as female sexual dysfunction. Summary of the Invention

[0006] The present inventors have unexpectedly discovered that the primary metabolic pathway of substituted 4,5,7,8-tetrahydro-2H-imidazo[1,2-a]pyrrolo[3,4-e]pyrimidines or 4,5,7,8,9-pentahydro-2H-pyrimido[1,2-a]pyrrolo[3,4-e]pyrimidines of formula 1a is via hydroxylation at the cyclopentyl and / or phenylamino rings. For example, compound 1 is metabolized to give compounds of formulae MI, M-II, and M-III, as shown below: [ka] The inventors further found that the metabolite of formula MI accounted for 84% of the total circulating drug-related substances in human plasma following oral administration of Compound 1.

[0007] Without being bound by theory, the present invention provides compounds that specifically limit and / or prevent metabolism occurring through these pathways. 1 Deuterium ( 2 Because the properties of the H) atom are very similar, it is believed that drug compounds in which deuterium is substituted for hydrogen will generally have similar biological activity as the non-deuterated analogue, but may have improved pharmacokinetic properties. The degree to which such substitutions result in improved pharmacokinetic properties without an overly significant loss of pharmacokinetic activity varies. Thus, in some situations, the resulting deuterated compounds will only show a modest increase in pharmacokinetic stability, while in other situations, the resulting deuterated compounds may have significantly improved stability. Furthermore, the effects of simultaneous deuterium substitutions may be difficult to predict with certainty. They may or may not result in additive (synergistic) improvements in metabolic stability.

[0008] In various embodiments, the present invention provides various PDE1 inhibitory compounds for use in treating any one or more of the following conditions, comprising administering to a human or animal patient in need thereof an effective amount of a compound of the invention, e.g., a compound according to any of Formulas Ia or 1.1-1.26, in free form or in a pharma- ceutical acceptable salt or prodrug form: (i) Neurodegenerative diseases, including Parkinson's disease, restless legs, tremors, dyskinesia, Huntington's disease, Alzheimer's disease and drug-induced movement disorders; (ii) Psychiatric disorders, including depression, attention deficit disorder, attention deficit hyperactivity disorder, bipolar illness, anxiety, sleep disorders, e.g. narcolepsy, cognitive impairment, e.g. in schizophrenia, dementia, Tourette's syndrome, autism, fragile X syndrome, psychostimulant withdrawal and drug dependence; (iii) circulatory and cardiovascular disorders, including cerebrovascular disease, stroke, congestive heart disease, hypertension, pulmonary hypertension (e.g., pulmonary arterial hypertension), and sexual dysfunction, including cardiovascular diseases and related disorders described in International Application No. PCT / US2014 / 16741, the contents of which are incorporated herein by reference; (iv) respiratory and inflammatory disorders, including asthma, chronic obstructive pulmonary disease and allergic rhinitis, as well as autoimmune and inflammatory diseases; (v) diseases that may be alleviated by enhancing progesterone signaling, such as female sexual dysfunction; (vi) a disease or disorder such as psychiatric illness, glaucoma or elevated intraocular pressure; (vii) traumatic brain injury; (viii) a cancer or tumor, e.g., a brain tumor, a glioma (e.g., an ependymoma, an astrocytoma, an oligodendroglioma, a brain stem glioma, an optic nerve glioma, or a mixed glioma, e.g., an oligoastrocytoma), an astrocytoma (e.g., a glioblastoma multiforme), an osteosarcoma, a melanoma, a leukemia, a neuroblastoma, or a leukemia; (ix) kidney disorders, e.g., renal fibrosis, chronic kidney disease, renal failure, glomerulosclerosis and nephritis; (x) a disease or condition characterized by low levels of cAMP and / or cGMP (or inhibition of the cAMP and / or cGMP signaling pathways) in cells expressing PDE1; and / or (xi) A disease or condition characterized by decreased dopamine D1 receptor signaling activity.

[0009] In various embodiments, the present invention provides the following compound: [ka] The present invention provides a method for preventing the formation of one or more metabolites of a PDE1 inhibitor, the method comprising deuterizing the PDE1 inhibitor to prevent the formation of one or more metabolites.

[0010] Further embodiments of the present invention are shown or will be apparent from the following detailed description and examples herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Detailed Description Compounds of the Disclosure In one embodiment, the disclosure provides that the PDE1 inhibitor for use in the methods described herein is a compound represented by formula 1a: [ka] [In the formula, (i) R2 and R5 are independently H, D or hydroxy and R3 and R4 together form a trimethylene or tetramethylene bridge [preferably the carbons bearing R3 and R4 have the R and S configurations, respectively]; or R2 and R3 are each methyl and R4 and R5 are each H; or R2, R4 and R5 are H and R3 is isopropyl [preferably the carbon bearing R3 has the R configuration]; (ii) R6 is phenylamino (which may be halo- or hydroxy-substituted), benzylamino (which may be halo- or hydroxy-substituted), C 1-4 Alkyl, or C 1-4 alkylsulfide; for example, phenylamino or 4-fluorophenylamino; (iii) R 10 is C 1-4 alkyl, methylcarbonyl, hydroxyethyl, carboxylic acid, sulfonamide, (optionally halo- or hydroxy-substituted) phenyl, (optionally halo- or hydroxy-substituted) pyridyl (e.g., 6-fluoropyrid-2-yl), or thiadiazolyl (e.g., 1,2,3-thiadiazol-4-yl); X and Y are independently C or N. Provide that.

[0012] The present invention further provides compounds of formula Ia as follows:

[0013] 1.1 Compounds according to formula 1a, wherein R2 and R5 are independently D or hydroxy; or R6 is hydroxy-substituted phenylamino or hydroxy-substituted benzylamino.

[0014] 1.2 Compounds according to formula Ia or 1.1, wherein R2 and R5 are independently D or hydroxy.

[0015] 1.3 Compounds according to formula Ia or 1.1-1.2, wherein R6 is hydroxy-substituted phenylamino or hydroxy-substituted benzylamino.

[0016] 1.4 Compounds according to formula Ia or 1.1-1.3, wherein R6 is hydroxy-substituted phenylamino.

[0017] 1.5 Compounds according to formula Ia or 1.1-1.3, wherein R6 is hydroxy-substituted benzylamino.

[0018] 1.6 Compounds according to formula Ia or 1.1-1.5, wherein R2 and R5 are independently H, D or hydroxy, and R3 and R4 together form a trimethylene or tetramethylene bridge, preferably wherein the carbons carrying R3 and R4 have the R and S configurations, respectively.

[0019] 1.7 Compounds according to formula 1a or 1.1-1.6, wherein at least one of R2 and R5 is D.

[0020] 1.8 Compounds according to formula 1a or 1.1-1.7, wherein R2 and R5 are both D.

[0021] 1.9 Compounds according to formula 1a or 1.1-1.8, wherein R2 and R5 are both D and R3 and R4 together form a trimethylene or tetramethylene bridge.

[0022] 1.10 Compounds according to formula 1a or 1.1-1.5, wherein at least one of R2 and R5 is hydroxy.

[0023] 1.11 Compounds according to formula 1a, 1.1-1.5 or 1.10, wherein at least one of R2 and R5 is hydroxy, and R3 and R4 together form a trimethylene or tetramethylene bridge.

[0024] 1.12 Compounds according to formula 1a, 1.1-1.5 or 1.10-1.11, wherein R2 is hydroxy.

[0025] 1.13 Compounds according to formula 1a, 1.1-1.5 or 1.0-1.11, wherein R5 is hydroxy.

[0026] 1.14 R 10 is pyridyl.

[0027] 1.15 R 10A compound according to formula 1a or 1.1-1.12, wherein is halo- or hydroxy-substituted pyridyl.

[0028] 1.16 R 10 A compound according to formula 1a or 1.1-1.12, wherein is halo-substituted pyridyl.

[0029] 1.17 R 10 A compound according to formula 1a or 1.1-1.12, wherein is a hydroxy-substituted pyridyl.

[0030] 1.18 R 10 A compound according to formula 1a or 1.1-1.12, wherein is 6-fluoropyrid-2-yl.

[0031] 1.19 Compounds according to formula 1a or 1.1-1.18, wherein X and Y are both C.

[0032] 1.20 The PDE1 inhibitor is selected from the group consisting of the compounds: [ka] [ka] A compound according to formula 1a or 1.1-1.19,

[0033] 1.21 The PDE1 inhibitor is selected from the group consisting of the compounds: [ka] [ka] A compound according to formula 1a or 1.1-1.20,

[0034] 1.22 The PDE1 inhibitor is selected from the group consisting of the compounds: [ka] A compound according to formula 1a or 1.1-1.21,

[0035] 1.23 The PDE1 inhibitor is selected from the group consisting of the compounds: [ka] A compound according to formula 1a or 1.1-1.22,

[0036] 1.24 The PDE1 inhibitor is selected from the group consisting of the compounds: [ka] A compound according to formula 1a or 1.1-1.22,

[0037] 1.25 The PDE1 inhibitor is selected from the group consisting of the compounds: [ka] A compound according to formula 1a or 1.1-1.22,

[0038] 1.26 The PDE1 inhibitor is selected from the group consisting of the compounds: [ka] A compound according to formula 1a or 1.1-1.21,

[0039] 1.27 Any of the above compounds, wherein the compound is deuterated, e.g., the deuterium:protium ratio at a particular position in the molecule is significantly higher than the natural isotope ratio, e.g., at least 2-fold, e.g., at least 10-fold higher.

[0040] In another embodiment, the disclosure further provides a radiolabeled PDE1 inhibitor [compound 2] according to formula 1a or 1.1-1.26, for use in the methods described herein, for example.

[0041] 2.1 At least one carbon atom is carbon-14 ([ 14 C]), compound 2.

[0042] 2.2 One carbon atom is carbon-14 ([14 C]) any of the above compounds.

[0043] 2.3 The radiolabeled PDE1 inhibitor is the compound: [ka] or a pharma- ceutically acceptable salt thereof.

[0044] 2.4 The compound 2.3, wherein the compound is in salt form.

[0045] 2.5 Compound 2.4, wherein the compound is in the phosphate form.

[0046] 2.6 Compound 2.5, wherein the compound is in the monophosphate form.

[0047] In one embodiment, the selective PDE1 inhibitors of the above formulae (e.g., Formulae Ia or 1.1-1.26) are compounds that inhibit phosphodiesterase-mediated (e.g., PDE1-mediated, particularly PDE1B-mediated) hydrolysis of cGMP, e.g., preferred compounds have an IC of less than 1 μM, preferably less than 500 nM, preferably less than 50 nM, preferably less than 5 nM, in the immobilized metal affinity particle reagent PDE assay, in free or salt form. 50 has.

[0048] Unless otherwise specified or clear from context, the following terms used herein have the following meanings:

[0049] "Alkyl," as used herein, refers to a saturated or unsaturated hydrocarbon moiety, preferably saturated, preferably having 1 to 6 carbon atoms, which may be straight or branched chain, and which may be mono-, di- or tri-substituted, for example, by halogen (e.g., chloro or fluoro), hydroxy or carboxy.

[0050] "Cycloalkyl" as used herein refers to a saturated or unsaturated non-aromatic hydrocarbon moiety, preferably saturated, containing preferably 3 to 9 carbon atoms, at least some of which form a non-aromatic monocyclic or bicyclic or bridged ring structure, which may be optionally substituted, for example, with halogen (e.g., chloro or fluoro), hydroxy or carboxy. When a cycloalkyl may contain one or more atoms selected from N and O and / or S, the cycloalkyl may be a heterocycloalkyl.

[0051] "Heterocycloalkyl", unless otherwise specified, means a saturated or unsaturated non-aromatic hydrocarbon moiety, preferably saturated, containing preferably from 3 to 9 carbon atoms, at least some of which are formed into a non-aromatic monocyclic or bicyclic or bridged ring structure, in which at least one carbon atom is replaced by N, O or S, and in which the heterocycloalkyl may be optionally substituted, for example, by halogen (e.g., chloro or fluoro), hydroxy or carboxy.

[0052] "Aryl," as used herein, refers to a monocyclic or bicyclic aromatic hydrocarbon, preferably phenyl, optionally substituted with, for example, alkyl (e.g., methyl), halogen (e.g., chloro or fluoro), haloalkyl (e.g., trifluoromethyl), hydroxy, carboxy, or further aryl or heteroaryl (e.g., biphenyl or pyridylphenyl).

[0053] "Heteroaryl," as used herein, refers to an aromatic moiety in which one or more of the atoms comprising the aromatic ring is sulfur or nitrogen rather than carbon, e.g., pyridyl or thiadiazolyl, and may be optionally substituted, e.g., with alkyl, halogen, haloalkyl, hydroxy or carboxy.

[0054] When a substituent ends in "ene," such as an alkylene, phenylene, or arylalkylene, the substituent is intended to bridge or connect two other substituents. Thus, methylene is intended to be -CH-, phenylene is intended to be -CH-, and arylalkylene is intended to be -CH-CH- or -CH-CH-.

[0055] The compounds of the present invention, such as substituted 4,5,7,8-tetrahydro-2H-imidazo[1,2-a]pyrrolo[3,4-e]pyrimidines or 4,5,7,8,9-pentahydro-2H-pyrimido[1,2-a]pyrrolo[3,4-e]pyrimidines, such as compounds of formula Ia, may exist in free form or in salt form, such as an acid addition salt. In this specification, unless otherwise specified, phrases such as "compounds of the present invention" should be understood to include the compounds in any form, such as free form or acid addition salt form, or, if the compound contains an acidic substituent, base addition salt form. Since the compounds of the present invention are intended for use as pharmaceuticals, pharma- ceutically acceptable salts are preferred. Salts that are not suitable for pharmaceutical use may be useful, for example, for the isolation or purification of the free compounds of the present invention or their pharma- ceutical acceptable salts, and therefore are also included.

[0056] The compounds of the present invention may also exist in prodrug form in some cases. Prodrug forms are compounds that are converted to the compounds of the present invention in the body. For example, when the compounds of the present invention contain hydroxy or carboxy substituents, these substituents may form physiologically hydrolyzable and acceptable esters. As used herein, "physiologically hydrolyzable and acceptable esters" refers to esters of the compounds of the present invention that are hydrolyzable under physiological conditions to produce an acid (in the case of the compounds of the present invention having a hydroxy substituent) or an alcohol (in the case of the compounds of the present invention having a carboxy substituent) that is itself physiologically acceptable in the dose to be administered. Thus, when the compounds of the present invention contain a hydroxy group, for example the compound -OH, an acyl ester prodrug of the compound, i.e., the compound -OC(O)-C 1-4Alkyl groups can be hydrolyzed in the body to form physiologically hydrolyzable alcohols (compounds -OH) on the one hand, and acids (e.g., HOC(O)-C 1-4 Alternatively, when a compound of the invention contains a carboxylic acid, e.g., Compound -C(O)OH, an acid ester prodrug of that compound, Compound -C(O)OC 1-4 The alkyl group is hydrolyzed to give the compounds -C(O)OH and HO-C 1-4 Alkyl can be formed. Thus, as will be understood, this term encompasses conventional pharmaceutical prodrug forms.

[0057] In another embodiment, the present invention further provides a pharmaceutical composition comprising a compound of the present invention, in free form or in a pharma- ceutically acceptable salt form, in admixture with a pharma- ceutically acceptable carrier, for use in the treatment of a disease or disorder mediated by PDE1.

[0058] The compounds of the present invention may also exist in prodrug form in some cases. Prodrug forms are compounds that are converted to the compounds of the present invention in the body. For example, when the compounds of the present invention contain hydroxy or carboxy substituents, these substituents may form physiologically hydrolyzable and acceptable esters. As used herein, "physiologically hydrolyzable and acceptable esters" refers to esters of the compounds of the present invention that are hydrolyzable under physiological conditions to produce an acid (in the case of the compounds of the present invention having a hydroxy substituent) or an alcohol (in the case of the compounds of the present invention having a carboxy substituent) that is itself physiologically acceptable in the dose to be administered. Thus, when the compounds of the present invention contain a hydroxy group, for example the compound -OH, an acyl ester prodrug of the compound, i.e., the compound -OC(O)-C 1-4 Alkyl groups can be hydrolyzed in the body to form physiologically hydrolyzable alcohols (compounds -OH) on the one hand, and acids (e.g., HOC(O)-C 1-4Alternatively, when a compound of the invention contains a carboxylic acid, e.g., Compound -C(O)OH, an acid ester prodrug of that compound, Compound -C(O)OC 1-4 The alkyl group is hydrolyzed to give the compounds -C(O)OH and HO-C 1-4 Alkyl can be formed. Thus, as will be understood, this term encompasses conventional pharmaceutical prodrug forms.

[0059] In another embodiment, the present invention further provides a pharmaceutical composition for use in the treatment of a disease or disorder mediated by PDE1, comprising a compound of the present invention in free form, a pharma- ceutically acceptable salt form or a prodrug form in admixture with a pharma- ceutically acceptable carrier.

[0060] Method for producing the compound of the present invention The compounds of the present invention and their pharma- ceutically acceptable salts can be prepared using or by methods similar to those described and exemplified herein, or by methods known in the chemical arts, including, but not limited to, those described below. The starting materials for these processes, if not commercially available, can be prepared by procedures selected from the chemical arts using techniques similar or analogous to those used for the synthesis of known compounds.

[0061] Various starting materials and / or compounds of the present invention may be prepared using the methods disclosed in U.S. Patent Application Publication No. 2008-0188492 (A1), U.S. Patent Application Publication No. 2010-0173878 (A1), U.S. Patent Application Publication No. 2010-0273754 (A1), U.S. Patent Application Publication No. 2010-0273753 (A1), WO 2010 / 065153, WO 2010 / 065151, WO 2010 / 065151, WO 2010 / 065149, WO 2010 / 065152, WO 2010 / 065153, WO 2010 / 065154, WO 2010 / 065152, WO 2010 / 065149, WO 2010 / 065153 ... The compounds can be prepared using the methods described in Publication No. 2010 / 065147, Publication No. WO 2010 / 065152, Publication No. WO 2011 / 153129, Publication No. WO 2011 / 133224, Publication No. WO 2011 / 153135, Publication No. WO 2011 / 153136, Publication No. WO 2011 / 153138, and U.S. Pat. No. 9,073,936, the contents of each of which are incorporated herein by reference in their entirety.

[0062] The compounds of the present invention include their enantiomers, diastereoisomers and racemates, as well as their polymorphs, hydrates, solvates and complexes.Some individual compounds within the scope of the present invention may contain double bonds.The expression of double bonds in the present invention is meant to include both the E and Z isomers of the double bond.In addition, some compounds within the scope of the present invention may contain one or more asymmetric centers.The present invention includes the use of any of the optically pure stereoisomers, and combinations of stereoisomers.

[0063] It is also intended that the compounds of the present invention encompass their stable and unstable isotopes. A stable isotope is a non-radioactive isotope that contains one additional neutron compared to the abundant nuclide of the same species (i.e., element). The activity of compounds containing such isotopes is retained, and such compounds are also believed to have utility for measuring the pharmacokinetics of non-isotopic analogs. For example, a hydrogen atom at a position of a compound of the present invention can be replaced with deuterium (a non-radioactive stable isotope). Examples of known stable isotopes include deuterium, 13 C. 15 N, 18Alternatively, unstable isotopes, which are radioisotopes that contain additional neutrons compared to the abundant nuclide of the same species (i.e., element), e.g. 123 I, 131 I, 125 I, 11 C. 18 F may be replaced by the corresponding abundant species of I, C, and F. Another example of a useful isotope of the compounds of the invention is: 11 C isotope. These radioisotopes are useful for radioimaging and / or pharmacokinetic studies of the compounds of the invention.

[0064] Melting points are uncorrected and (dec) indicates decomposition. Temperatures are given in degrees Celsius (°C); unless otherwise stated, operations are performed at room or ambient temperature, i.e., at temperatures in the range of 18-25°C. Chromatography means silica gel flash chromatography; thin layer chromatography (TLC) is performed on silica gel plates. NMR data are given in delta values ​​of major diagnostic protons expressed in parts per million (ppm) relative to tetramethylsilane (TMS) as internal standard. Conventional abbreviations for signal shapes are used. Coupling constants (J) are expressed in Hz. For mass spectra (MS), the major ion of smallest mass is reported for molecules where isotopic splitting gives rise to multiple mass spectral peaks. Compositions of solvent mixtures are given as volume percentages or volume ratios. In cases where the NMR spectra are complex, only characteristic signals are reported.

[0065] Methods of Using the Compounds of the Invention The compounds of the present invention are useful for treating diseases characterized by disruption or damage of cAMP and cGMP mediated pathways as a result of increased expression of PDE1 or decreased expression of cAMP and cGMP due to inhibition or decreased levels of inducers of cyclic nucleotide synthesis, such as dopamine and nitric oxide (NO).By preventing the degradation of cAMP and cGMP by PDE1 and increasing the intracellular levels of cAMP and cGMP, the compounds of the present invention enhance the activity of cyclic nucleotide synthesis inducers.

[0066] The invention provides methods of treatment of any one or more of the following conditions comprising administering to a human or animal patient in need thereof an effective amount of a compound of the invention, e.g., a compound according to any of Formulas Ia or 1.1-1.26, in free form or in a pharma- ceutically acceptable salt or prodrug form: (i) Neurodegenerative diseases, including Parkinson's disease, restless legs, tremors, dyskinesia, Huntington's disease, Alzheimer's disease and drug-induced movement disorders; (ii) Psychiatric disorders, including depression, attention deficit disorder, attention deficit hyperactivity disorder, bipolar illness, anxiety, sleep disorders, e.g. narcolepsy, cognitive impairment, e.g. in schizophrenia, dementia, Tourette's syndrome, autism, fragile X syndrome, psychostimulant withdrawal and drug dependence; (iii) circulatory and cardiovascular disorders, including cerebrovascular disease, stroke, congestive heart disease, hypertension, pulmonary hypertension (e.g., pulmonary arterial hypertension), and sexual dysfunction, including cardiovascular diseases and related disorders described in International Application No. PCT / US2014 / 16741, the contents of which are incorporated herein by reference; (iv) respiratory and inflammatory disorders, including asthma, chronic obstructive pulmonary disease and allergic rhinitis, as well as autoimmune and inflammatory diseases; (v) diseases that may be alleviated by enhancing progesterone signaling, such as female sexual dysfunction; (vi) a disease or disorder such as psychiatric illness, glaucoma or elevated intraocular pressure; (vii) traumatic brain injury; (viii) a disease or condition characterized by low levels of cAMP and / or cGMP (or inhibition of the cAMP and / or cGMP signaling pathways) in cells expressing PDE1; and / or (ix) A disease or condition characterized by decreased dopamine D1 receptor signaling activity.

[0067] The compounds of the present invention are useful in the treatment of inflammatory diseases or conditions, particularly neuroinflammatory diseases or conditions.Accordingly, the administration or use of the preferred PDE1 inhibitors described herein, such as the PDE1 inhibitors described above, such as the compounds of formula Ia, provides a means of regulating inflammation (e.g., preventing, reducing and / or reversing neuroinflammation and diseases or disorders associated with neuroinflammation), and in certain embodiments provides treatment of various inflammatory diseases and disorders.In certain embodiments, the inflammatory disease or condition is selected from the following, including administering to a patient in need thereof an effective amount of the PDE1 inhibitors of the present invention (e.g., the PDE1 inhibitors of formula Ia described herein), such as an amount effective to (i) reduce or inhibit the activation of M1 microglia, and / or (ii) reduce the level of one or more proinflammatory cytokines (e.g., IL1β, TNFα and Ccl2, or a combination thereof): a. Neurodegenerative conditions such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and demyelinating conditions such as multiple sclerosis (MS), and prion diseases; b. Stroke, cardiac arrest, hypoxia, intracerebral hemorrhage or traumatic brain injury; c. conditions characterized by abnormal neurotransmitter production and / or response, including depression, schizophrenia, post-traumatic stress disorder, anxiety, attention deficit disorder, and bipolar disorder; for example, any of the above are associated with neuroinflammation; d. Chronic CNS infections, e.g., Lyme disease, or CNS infections resulting from an immunosuppressive state, e.g., HIV dementia; e. Chemotherapy-induced neuroinflammation.

[0068] The compounds of the present invention are useful for treating cancer or tumor, for example inhibiting the proliferation of cancerous or neoplastic cells.Accordingly, the administration or use of the preferred PDE1 inhibitors described herein, for example the PDE1 inhibitors described above, for example the compound of formula Ia, in treating or preventing cancer or tumor.

[0069] The compounds of the present disclosure may be used to treat acoustic neuroma, astrocytoma, chordoma, lymphoma (e.g., CNS lymphoma, Hodgkin's lymphoma or non-Hodgkin's lymphoma), craniopharyngioma, glioma (e.g., brain stem glioma, ependymoma, mixed glioma, optic nerve glioma), subependymoma, medulloblastoma, meningioma, metastatic brain tumor, oligodendroglioma, pituitary tumor, primitive neuroectodermal tumor (PNET), Schwannoma, adenoma (e.g., basophilic adenoma, acidophilic adenoma, chromophobe adenoma, parathyroid adenoma, pancreatic islet adenoma, fibroadenoma), fibroid (fibrous histiocytoma), fibroma, hemangioma, lipoma (e.g., angiolipoma, myelolipoma, fibrolipoma, spindle cell lipoma, brown lipoma, atypical lipoma), myxoma, osteoma, preleukemia, rhabdomyoma, papilloma, seborrheic keratosis, skin adnexal tumor, hepatic adenoma, renal tubular adenoma, bile duct adenoma, transitional cell papilloma, hydatidiform mole, ganglioneuroma, meningioma, schwannoma, neurofibroma, C-cell hyperplasia, pheochromocytoma, insulinoma, gastrinoma, carcinoid, chemodectoma, paraganglioma, nevus, actinic keratosis, cervical dysplasia, metaplasia (e.g., pulmonary metaplasia), leukoplakia, hemangioma, lymphangioma, carcinoma (e.g., squamous cell carcinoma, epidermoid carcinoma, adenocarcinoma, hepatoma, hepatocellular carcinoma, renal cell carcinoma (renal cell carcinoma, cholangiocarcinoma, transitional cell carcinoma, embryonal cell carcinoma, parathyroid carcinoma, medullary thyroid carcinoma, bronchial carcinoid, oat cell carcinoma, islet cell carcinoma, malignant carcinoid, Merkel cell carcinoma), sarcomas (e.g., fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteosarcoma, malignant fibrous histiocytoma, hemangiosarcoma, angiosarcoma, lymphangiosarcoma, leiomyosarcoma, rhabdomyosarcoma, neurofibrosarcoma), blastomas (e.g., medulloblastoma and glioblastoma, types of brain tumors) tumor, retinoblastoma, tumor of the retina of the eye, osteoblastoma, bone tumor, neuroblastoma, germ cell tumor, mesothelioma, malignant skin adnexal tumor, hypernephroma, seminoma, glioma, malignant meningioma, malignant schwannoma, malignant pheochromocytoma, malignant paraganglioma, melanoma, Merkel cell neoplasm, cystosarcoma phyllodesIt is contemplated that the present invention may be used to treat tumors or cancers selected from one or more of: pulmonary fibrosis, ...

[0070] The present invention also provides compounds and related methods that specifically limit and / or prevent the metabolism of PDE1 inhibitors. Thus, in one embodiment, the present invention provides a method (Method 1) of inhibiting the metabolism of a PDE1 inhibitor, e.g., a PDE1 inhibitor according to Formula 1a or 1.1-1.26, comprising deuterizing the PDE1 inhibitor to prevent the formation of one or more metabolites.

[0071] 1.1. The PDE1 inhibitor has the following formula: [ka] The compound according to method 1.

[0072] 1.2. Deuteration of PDE1 inhibitors [ka] of [ka] React with [ka] Any of the above methods comprising forming

[0073] 1.3. Deuteration of PDE1 inhibitors [ka] of [ka] React with [ka] forming a

[0074] 1.4. The above process, wherein the reaction is carried out in benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate, THF and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0075] 1.5. [ka] reacts with thionyl chloride in THF to give [ka] The two above methods form:

[0076] 1.6. Method 1.2, wherein the reaction is carried out in benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate, THF and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0077] 1.7. [ka] reacts with thionyl chloride in THF to give the following product: [ka] and subjecting the product to chiral column separation to [ka] , method 1.2 or 1.6.

[0078] The phrase "a compound of the invention" or "a PDE1 inhibitor of the invention" or similar terms includes all of the compounds disclosed herein, for example, compounds of Formula Ia or 1.1-1.26.

[0079] The terms "treatment" and "treating" should be understood to encompass prevention and treatment or amelioration of symptoms of disease, as well as treatment of the cause of disease, as appropriate.

[0080] With respect to treatment methods, the term "effective amount" is intended to encompass a therapeutically effective amount for treating or alleviating a particular disease or disorder, and / or its symptoms, and / or for inhibiting PDE1 expression in a patient or subject.

[0081] The term "patient" includes a human patient or a non-human (i.e., animal) patient. In certain embodiments, the invention includes both human and non-human animals. In other embodiments, the invention includes non-human animals. In other embodiments, the term includes humans.

[0082] The term "comprising" is used in this disclosure is intended to be open-ended and does not exclude additional, unrecited elements or method steps.

[0083] The compounds of the present invention, e.g., those of formulae Ia and 1.1-1.26 as described above, in free form or in pharma- ceutically acceptable salt form, can be used as the sole therapeutic agent, but can also be used in combination or for coadministration with other active agents.

[0084] For example, in certain embodiments, a compound of the invention, e.g., a compound of Formula Ia or 1.1-1.26 as described herein, in free form or in pharma- ceutically acceptable salt form, is administered in combination (e.g., administered sequentially or simultaneously or within 24 hours) with another active agent, e.g., one or more compounds, in free form or in pharma- ceutically acceptable salt form, selected from one or more antidepressants, e.g., selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), c) tricyclic antidepressants (TCAs), and atypical antipsychotics.

[0085] Doses used in practicing the invention will of course vary depending, for example, on the particular disease or condition being treated, the particular compound of the invention being used, the mode of administration, and the desired therapy. The compounds of the invention may be administered by any suitable route, including orally, parenterally, transdermally, or by inhalation, but are preferably administered orally. In general, for the treatment of diseases such as those mentioned above, satisfactory results have been shown to be obtained by oral administration at doses on the order of about 0.01-2.0 mg / kg. In larger mammals, such as humans, the indicated daily dose for oral administration will accordingly range from about 0.75 to 150 mg (depending on the drug administered and the condition being treated, e.g., in the case of compound 214, 0.5 to 25 mg, e.g., 1 to 10 mg, per day, e.g., in monophosphate form, for the treatment of PDE1-mediated conditions), conveniently administered once daily or in divided doses 2 to 4 times daily, or in sustained release dosage form. Thus, a unit dosage form for oral administration may contain, for example, from about 0.2 to 75 or 150 mg, for example from about 0.2 or 2.0 to 50, 75 or 100 mg (1, 2.5, 5, 10 or 20 mg), of a compound of the invention, together with a pharma- ceutically acceptable diluent or carrier.

[0086] Pharmaceutical compositions containing the compounds of the present invention can be prepared using conventional diluents or excipients and techniques known in the galenic art. Thus, oral dosage forms can include tablets, capsules, solutions, suspensions, and the like. EXAMPLES

[0087] Example 1 Measurement of PDEIB inhibition in vitro using the IMAP phosphodiesterase assay kit Phosphodiesterase IB (PDEIB) is a calcium / calmodulin-dependent phosphodiesterase enzyme that converts cyclic guanosine monophosphate (cGMP) to 5'-guanosine monophosphate (5'-GMP). PDEIB can also convert modified cGMP substrates, such as the fluorescent molecule cGMP-fluorescein, to the corresponding GMP-fluorescein. The production of GMP-fluorescein from cGMP-fluorescein can be quantified, for example, using the IMAP (Molecular Devices, Sunnyvale, CA) immobilized metal affinity particle reagent.

[0088] Briefly, IMAP reagents bind with high affinity to the free 5'-phosphate present in GMP-fluorescein but absent in cGMP-fluorescein. The resulting GMP-fluorescein-IMAP complex is large relative to cGMP-fluorescein. Small fluorophores bound to the large, slowly tumbling complex can be distinguished from unbound fluorophores because the photons emitted when they fluoresce retain the same polarity as the photons used to excite the fluorescence.

[0089] In the phosphodiesterase assay, cGMP-fluorescein, which cannot bind to IMAP and therefore retains little fluorescence polarization, is converted to GMP-fluorescein, which upon binding to IMAP leads to a large increase in fluorescence polarization (Amp). Thus, inhibition of phosphodiesterase is detected as a decrease in Amp.

[0090] Enzyme assays Materials: All chemicals are available from Sigma-Aldrich (St. Louis, MO), except for IMAP reagents (reaction buffer, binding buffer, FL-GMP and IMAP beads) which are available from Molecular Devices (Sunnyvale, CA).

[0091] Assay: The following phosphodiesterase enzymes can be used: 3',5'-cyclic nucleotide specific bovine brain phosphodiesterase (Sigma, St. Louis, MO) (mainly PDEIB) and recombinant full-length human PDE1A and PDE1B (r-hPDE1A and r-hPDE1B, respectively) (e.g., can be produced in HEK cells or SF9 cells by those skilled in the art). PDE1 enzyme is reconstituted with 50% glycerol to 2.5U / ml. One unit of enzyme hydrolyzes 1.0 μmol of 3',5'-cAMP to 5'-AMP per minute at pH 7.5 and 30°C. One part enzyme is added to 1999 parts reaction buffer (30 μM CaCl2, 10 U / ml calmodulin (Sigma P2277), 10 mM Tris-HCl pH 7.2, 10 mM MgCl2, 0.1% BSA, 0.05% NaN3) to give a final concentration of 1.26 mU / ml. 99 μl of the diluted enzyme solution is added to each well of a flat-bottom 96-well polystyrene plate, to which 1 μl of test compound dissolved in 100% DMSO is added. Compounds are mixed and pre-incubated with the enzyme for 10 minutes at room temperature.

[0092] In a 384-well microtiter plate, FL-GMP conversion reaction is initiated by combining 4 parts of enzyme and inhibitor mixture with 1 part of substrate solution (0.225 μM). The reaction is incubated at room temperature in the dark for 15 minutes. The reaction is stopped by adding 60 μL of binding reagent (IMAP beads at 1:400 dilution in binding buffer with antifoam at 1:1800 dilution) to each well of the 384-well plate. The plate is incubated at room temperature for 1 hour to allow IMAP binding to proceed to completion, and then placed in an Envision multimode microplate reader (PerkinElmer, Shelton, CT) to measure fluorescence polarization (Amp).

[0093] A decrease in GMP concentration, measured as a decrease in Amp, indicates inhibition of PDE activity. Enzyme activity is measured in the presence of 8 to 16 concentrations of compound ranging from 0.0037 nM to 80,000 nM, and then IC is determined by plotting drug concentration versus Amp. 50 IC values ​​were determined using nonlinear regression software (XLFit; IDBS, Cambridge, MA). 50 The value can be estimated.

[0094] The compounds of the present disclosure are tested for PDE1 inhibitory activity in the assays described herein or similarly described.For example, compounds 1, 2 and 3 are identified as metabolites of a specific PDE1 inhibitor having the following structure: [ka] [ka] [ka]

[0095] As shown in the table below, these compounds have potency against PDE1 at nanomolar or sub-nanomolar levels and generally high selectivity over other PDE families: [Table 1]

[0096] Example 2 Synthesis of (6aS,9aR)-6a,9a-dideuterio-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-(phenylamino)-5,6a,7,8,9,9a-hexahydrocyclopenta[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(2H)-one The title compound is generally prepared according to Scheme 1.

[0097] [ka]

[0098] 2-(Hydroxyimino)cyclopentanone (2). To a solution of NaOH (2.816 g, 70.42 mmol) in water (30 mL) at 0° C., a solution of ethyl 2-oxocyclopentanecarboxylate (10.0 g, 64.02 mmol) and sodium nitrite (4.417 g, 64.02 mmol) in water (25 mL) is added dropwise successively over 20 min. The reaction mixture is stirred at room temperature for 2 days and cooled to 0° C. The cooled mixture is acidified to pH=5 with 6N H2SO4 (8 mL, 48.0 mmol). Diethyl ether (100 mL) is added and the organic layer is separated. The aqueous phase is extracted with diethyl ether (2×100 mL). The extracts are combined and concentrated under reduced pressure. The residue is further purified by silica gel column chromatography using a gradient of 0-100% ethyl acetate in hexane as eluent. The title compound 2 is obtained as a light brown solid (2.41 g, 33%). MS (ESI) m / z [M + H] + . 1 H NMR (500 MHz, Chloroform-d) δ 2.83 (t, J = 7.5 Hz, 2H), 2.49 (t, J = 7.9 Hz, 2H), 2.12 - 2.03 (m, 2H).

[0099] 2-Amino-1,2-dideuteriocyclopentanol (3). To a solution of 2-(hydroxyimino)cyclopentanone 2 (1.16 g, 10.26 mmol) in CH3OD (7 mL) at 0° C., NaBD4 (646 mg, 15.38 mmol) is added in portions. The resulting mixture is stirred at 0° C. for 1 h, NiCl2 is added, and then NaBD4 (646 mg, 15.38 mmol) is added in portions. The mixture is stirred at 0° C. for 0.5 h and at room temperature for 2 h. The solvent is removed under reduced pressure and the residue is extracted with a mixture of CH2Cl2 and CH3OH (10:1, 3×70 mL). The combined extracts are evaporated and further dried under high vacuum to give the title compound 3 as a pale pink solid (0.88 g, crude). MS (ESI) m / z 104.04 [M + H] + The crude product is used directly for the next reaction without further purification.

[0100] 3-Chloro-2-(4-(6-fluoropyridin-2-yl)benzyl)-7-(4-methoxybenzyl)-5-methyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione (5). A solution of 2-(4-(6-fluoropyridin-2-yl)benzyl)-7-(4-methoxybenzyl)-5-methyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione 4 (9.04 g, 38.2 mmol) in THF (100 mL) is cooled to 0° C. under argon and lithium bis(trimethylsilyl)amide in toluene (1 M, 25.5 mL, 25.5 mmol) is added dropwise via syringe. The reaction mixture is stirred at 0° C. for 4 h and quenched with water (30 mL). The mixture is stirred at room temperature for 5 minutes and the precipitate is filtered. The filter cake is washed with water (100 mL). Suspended in ethyl acetate (100 mL). The mixture is filtered and the filter cake is dried under high vacuum to give the title compound as a white solid (4.78 g, 45% yield). MS (ESI) m / z 506.14 [M + H] + .

[0101] 2-(4-(6-fluoropyridin-2-yl)benzyl)-7-(4-methoxybenzyl)-5-methyl-3-(phenylamino)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione (6). A suspension of 3-chloro-2-(4-(6-fluoropyridin-2-yl)benzyl)-7-(4-methoxybenzyl)-5-methyl-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione 5 (4.37 g, 8.65 mmol), aniline (1.18 mL, 13 mmol), cesium carbonate (5.63 g, 17.3 mmol), XPhos (1.6 g, 3.37 mmol) and tris(dibenzylideneacetone)dipalladium(0) (2.37 g, 2.6 mmol) in DMF (40 mL) is purged with argon at room temperature for 5 min and heated to 100° C. The mixture is stirred at this temperature for 5 h until the reaction is complete. The solvent is evaporated and the residue is purified by silica gel column chromatography using a gradient of 0-50% ethyl acetate in hexane. The title compound is obtained as an off-white solid (4.34 g, 89% yield). MS (ESI) m / z 563.2019 [M + H] + .

[0102] 2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-(phenylamino)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione (7). To a solution of 2-(4-(6-fluoropyridin-2-yl)benzyl)-7-(4-methoxybenzyl)-5-methyl-3-(phenylamino)-2H-pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-dione 6 (3.44 g, 6.11 mmol) in DCM (6 mL) at room temperature under argon is added trifluoroacetic acid (6.09 mL, 79.4 mmol) followed by trifluoromethanesulfonic acid (1.96 mL, 22 mmol). The resulting solution is stirred at room temperature for 2 h and the solvent is removed under reduced pressure. The residue is neutralized with 7N ammonia in methanol and the mixture is evaporated to dryness. Ethyl acetate (30 mL) is added to the residue and the resulting mixture is filtered. The filter cake is washed with water (60 mL) and dried under high vacuum to give 1.21 g of the title compound. The filtrates are combined and evaporated to dryness. The residue is suspended in methanol (60 mL) and the suspension is filtered. The filter cake is dried under vacuum to give 0.94 g of the title compound. (Total 2.15 g, 79% yield). MS (ESI) m / z 443.1474 [M + H] + . 1 H NMR (500 MHz, DMSO-d6) δ 11.52 (s, 1H), 8.77 (s, 1H), 8.12 - 8.03 (m, 1H), 7.99 (d, 2H), 7.90 (dd, J = 7.6, 2.6 Hz, 1H), 7.25 (d, 2H), 7.18 (dd, J = 8.5, 7.2 Hz, 2H), 7.13 (dd, J = 8.1, 2.7 Hz, 1H), 6.91 - 6.75 (m, 3H), 5.27 (s, 2H), 3.34 (s, 2H), 3.08 (s, 3H), 2.63 - 2.41 (m, 2H).

[0103] 6-((1,2-dideuterio-2-hydroxycyclopentyl)amino)-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-(phenylamino)-2H-pyrazolo[3,4-d]pyrimidin-4(5H)-one (8). To a suspension of 2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-(phenylamino)-2H-pyrazolo[3,4-d]pyrimidin-4,6(5H,7H)-dione 7 (0.8 g, crude) and BOP (1.04 g, 2.35 mmol) in anhydrous THF (4 mL) at room temperature under an argon atmosphere is added 8-diazabicyclo[5.4.0]undec-7-ene (0.83 mL, 5.45 mmol). After stirring the reaction mixture at room temperature for 5 min, solid 2-amino-1,2-dideuteriocyclopentanol (372 mg, crude) is added. The mixture is stirred at room temperature for 3 days. The solvent is removed and the residue is purified by silica gel column chromatography using a gradient of 0-100% mixed solvent in CHCl (CHCl:CHOH:7N NH in methanol = 10:1:0.1) as eluent. The obtained product (1.80 g, brown solid) contains other impurities and is used directly for the next reaction without further purification. MS (ESI) m / z 528.2061 [M + H] + .

[0104] 6a,9a-dideuterio-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-(phenylamino)-5,6a,7,8,9,9a-hexahydrocyclopenta[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(2H)-one (9). To a stirred solution of 6-((1,2-dideuterio-2-hydroxycyclopentyl)amino)-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-(phenylamino)-2H-pyrazolo[3,4-d]pyrimidin-4(5H)-one 8 (1.80 g, crude) in anhydrous DMF (10 mL) at room temperature under argon atmosphere was added thionyl chloride (0.360 mL, 4.96 mmol) dropwise. The reaction mixture is stirred for 2 hours and the solvent is removed under reduced pressure. The residue is purified by silica gel column chromatography using a gradient of 0-100% mixed solvent in ethyl acetate (ethyl acetate:methanol:7N ammonia in methanol = 10:1:0.1). The product obtained (332 mg) is further purified by semi-preparative HPLC system using a gradient of 0-30% acetonitrile in water containing 0.1% formic acid over 16 minutes. The title compound is obtained as an off-white solid (60 mg). MS (ESI) m / z 510.2071 [M + H] + .

[0105] (6aS,9aR)-6a,9a-dideuterio-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-(phenylamino)-5,6a,7,8,9,9a-hexahydrocyclopenta[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(2H)-one. 6a,9a-dideuterio-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-(phenylamino)-5,6a,7,8,9,9a-hexahydrocyclopenta[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(2H)-one 9 (60 mg) is dissolved in a mixture of hexane, isopropanol and diethylamine (volume 40:60:0.1) (10 mL). The solution is run on a semi-preparative HPLC system using a chiralpak AD-H column (20 x 250 mm) and eluted with a mixture of hexane, isopropanol and diethylamine (volume 40:60:0.1). The title compound is obtained as a white solid (19 mg, 32% yield). MS (ESI) m / z 510.2743 [M + H] + . 1H NMR (500 MHz, Chloroform-d) δ 7.92 - 7.86 (m, 2H), 7.86 - 7.80 (m, 1H), 7.58 (dd, J = 7.6, 2.4 Hz, 1H), 7.31 - 7.26 (m, 2H), 7.13 - 7.07 (m, 1H), 7.07 - 7.02 (m, 2H), 6.97 - 6.90 (m, 2H), 6.89 - 6.81 (m, 2H), 4.94 (s, 2H), 3.34 (s, 3H), 1.96 (s, 1H), 1.86 - 1.79 (m, 1H), 1.77 - 1.70 (m, 2H), 1.63 - 1.52 (m, 2H).

[0106] Example 3: New 14 Synthesis of [C]radiolabeled PDE1 inhibitors The novel radiolabeled PDE1 inhibitors are synthesized according to the following scheme:

[0107] TIFF0007612672000031.tif129154

[0108] According to known methods, for example as described in WO 2009 / 075784 A1 or WO 2014 / 205354 A1 (both of which are incorporated herein by reference in their entirety), (6aR,9aS)-3-chloro-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-5,6a,7,8,9,9a-hexahydrocyclopenta[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(2H)-one is synthesized. This compound is converted to [ 14 C] is added to a mixture of aniline, potassium carbonate, xantphos, and tris(dibenzylideneacetone)dipalladium(0), dissolved in 2-methyl-2-butanol (21 mL), frozen, and pumped under high vacuum. The mixture is purged with nitrogen, heated, filtered, and washed with ethanol. did .

[0109] The filtrate was first purified by column chromatography on silica eluting with ethyl acetate:ethanol, then by reversed-phase high performance liquid chromatography on a C18 column eluting with aqueous trifluoroacetic acid:acetonitrile. did The mixture is basified with potassium carbonate and then partitioned between ethyl acetate and water. Ta The solvent was removed from the organic layer in vacuum. 14 C] to give the free base ((6aR,9aS)-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-([U-14C]-phenylamino)-5,6a,7,8,9,9a-hexahydrocyclopenta[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4-(2H)-one). Ta .

[0110] Dissolve the free base in acetonitrile did The mixture was heated and a solution of phosphoric acid in acetonitrile was added under nitrogen. The mixture was then stirred under nitrogen. did The mixture is filtered and washed with acetonitrile. did The solid was dried over phosphorus pentoxide to give the phosphate ((6aR,9aS)-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-([U-14C]-phenylamino)-5,6a,7,8,9,9a-hexahydrocyclopenta[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4-(2H)-one phosphate). Ta . The present application also includes the following aspects. [Aspect 1] 1, in free form, in pharma- ceutically acceptable salt form or in prodrug form, of formula 1a: [ka] [In the formula, (i) R 2 and R 5 is independently H, D or hydroxy; R 3 and R 4 together form a trimethylene or tetramethylene bridge, preferably R 3 and R 4 the carbons carrying R and S configurations, respectively; or 2 and R 3 are methyl, and R 4 and R 5 are each H; or R 2 、R 4 and R 5 is H and R 3 is isopropyl; preferably, R 3 the carbon carrying the has the R configuration]; (ii) R 6 is optionally halo- or hydroxy-substituted phenylamino, optionally halo- or hydroxy-substituted benzylamino, C 1-4 Alkyl, or C 1-4 alkylsulfide; for example, phenylamino or 4-fluorophenylamino; (iii) R 10 is C 1-4 alkyl, methylcarbonyl, hydroxyethyl, carboxylic acid, sulfonamide, (optionally halo- or hydroxy-substituted) phenyl, (optionally halo- or hydroxy-substituted) pyridyl (e.g., 6-fluoropyrid-2-yl), or thiadiazolyl (e.g., 1,2,3-thiadiazol-4-yl); X and Y are independently C or N; Here, R 2 and R 5 is independently D or hydroxy; or R 6 is hydroxy-substituted phenylamino or hydroxy-substituted benzylamino; At least one carbon atom is carbon-14 ([ 14 C]) may be substituted. A compound represented by the formula: [Aspect 2] R 2 and R 5 is independently D or hydroxy. [Aspect 3] R 6 The compound of any preceding embodiment, wherein is hydroxy-substituted phenylamino or hydroxy-substituted benzylamino. [Aspect 4] R 6 The compound of any preceding embodiment, wherein is hydroxy-substituted phenylamino. [Aspect 5] R 2 and R 5 is independently H, D or hydroxy; R 3 and R 4

[0023] The compound of any preceding embodiment, wherein together form a trimethylene bridge or a tetramethylene bridge. [Aspect 6] R 2 and R 5 and are both D. [Aspect 7] R 2 and R 5 Both are D and R 3 and R 4

[0023] The compound of any preceding embodiment, wherein together form a trimethylene bridge or a tetramethylene bridge. [Aspect 8] R 2 and R 5 The compound according to any one of aspects 1 to 5, wherein at least one of is hydroxy. [Aspect 9] R 2 and R 5 One of the groups is hydroxy, and R 3 and R 4 The compound according to any one of embodiments 1 to 5 or 8, wherein together form a trimethylene bridge or a tetramethylene bridge. [Aspect 10] R 2 The compound according to any one of embodiments 1-5 or 8-9, wherein is hydroxy. [Aspect 11] R 5 The compound according to any one of embodiments 1-5 or 8-9, wherein is hydroxy. [Aspect 12] The PDE1 inhibitor is selected from the group consisting of the compounds:

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Claims

1. A compound of formula 1a, in free or pharma- ceutically acceptable salt form, including enantiomers, diastereoisomers and racemates: 【Chemistry 1】 [In the formula, (i) R 2 and R 5 is independently H, D or hydroxy; R 3 and R 4 together form a trimethylene or tetramethylene bridge; (ii) R 6 is optionally halo- or hydroxy-substituted phenylamino, optionally halo- or hydroxy-substituted benzylamino, C 1-4 Alkyl, or C 1-4 is an alkyl sulfide; (iii) R 10 is C 1-4 alkyl, methylcarbonyl, hydroxyethyl, carboxylic acid, sulfonamide, optionally halo- or hydroxy-substituted phenyl, optionally halo- or hydroxy-substituted pyridyl, or thiadiazolyl; X and Y are independently C or N; Here, R 2 and R 5 at least one of is hydroxy; At least one carbon atom is carbon-14 ([ 14 C]) may be substituted. A compound represented by the formula:

2. R 6 The compound of claim 1 , wherein is hydroxy-substituted phenylamino or hydroxy-substituted benzylamino.

3. R 6 The compound of claim 1 or 2, wherein is hydroxy substituted phenylamino.

4. R 2 The compound according to any one of claims 1 to 3, wherein is hydroxy.

5. R 5 The compound according to any one of claims 1 to 4, wherein is hydroxy.

6. A compound comprising: 【Chemistry 2】 2. The compound of claim 1 ,

7. One carbon atom is carbon-14 ([ 14 The compound according to any one of claims 1 to 6, wherein the compound is substituted with .

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