Process for synthesizing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid

Abstract

The present application relates to a process for synthesizing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid. Provided herein are processes, compounds, and compositions for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid. Also provided herein are pharmaceutical compositions containing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid.

Description

[0001] This application is a divisional application of an application filed on May 28, 2019, with application number 201980049170.X, and invention name “Process for synthesizing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid”.

[0002] This invention was made with government support under Grant R01DA030604 awarded by the National Institutes of Health. The government has certain rights in this invention.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims the benefit of and priority to U.S. Provisional Application No. 62 / 676,373, filed May 25, 2018; U.S. Provisional Application No. 62 / 814,026, filed March 5, 2019; and U.S. Provisional Application No. 62 / 835,776, filed April 18, 2019, all of which are incorporated herein by reference in their entirety. Technical Field

[0005] Synthesis of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid. background

[0006] (S) -3-amino-4- (difluoromethylene) cyclopent-1-ene-1-carboxylic acid is an inhibitor of gamma-aminobutyric acid aminotransferase (GABA-AT) and has been shown to be a possible treatment for epilepsy, addiction and hepatocellular carcinoma. See, for example, U.S. Patent No. 9,670,141 and Juncosa et al., J.Am.Chem.Soc.2018, 140, 2151-2164. GABA is an inhibitory neurotransmitter in the central nervous system (CNS). When the GABA concentration in the brain drops below the threshold level, convulsions may occur. Increasing GABA levels has been shown to stop convulsions. In addition, the increase in GABA concentration antagonizes the release of dopamine from the nucleus accumbens and is considered to be a possible treatment for addiction. The nucleus accumbens is an area of ​​the hypothalamus related to reward and motivation. Unfortunately, direct administration of GABA is not feasible because GABA does not cross the blood-brain barrier. However, GABA concentrations can be increased by inhibiting GABA aminotransferase (GABA-AT). 4-Aminohex-5-enoic acid, also known as vigabatrin (as Vigabatrin (available commercially) is currently the only FDA-approved GABA-AT inhibitor for the treatment of infantile spasms and has been shown to be a possible treatment for addiction. However, vigabatrin requires high doses (1 g / day to 3 g / day), inhibits multiple GABA receptors, and with prolonged use, causes retinal damage in 25% to 40% of patients.

[0007] In vivo studies in rats indicate that (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid is superior to previous GABA-AT inhibitors in inhibiting dopamine release in the striatum after exposure to cocaine or nicotine. (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid does not inhibit off-target aminotransferases such as alanine aminotransferase and aspartate aminotransferase. In addition, it does not inhibit the hERG potassium channel or various microsomal cytochrome P450 enzymes.

[0008] According to the prior art, (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid has been synthesized from (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid (also known as CPP-115) in six steps.

[0009]

[0010] See also, e.g., Juncosa et al., J. Am. Chem. Soc., supra, and U.S. Pat. Nos. 7,381,748, 6,794,413, and 9,670,141, each of which is incorporated herein by reference in its entirety.

[0011] CPP-115 is an inhibitor of GABA-AT and is currently in clinical trials for the treatment of epilepsy. It has been determined that (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid is 9.8 times more effective as a GABA-AT activator than CPP-115. Since the synthesis of CPP-115 requires 8 steps, the total synthesis steps from commercial starting materials to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid are counted as 14 steps, with an overall yield of 3.7%. The synthesis of CPP-115 involves the use of highly flammable tert-butyl lithium (on a gram scale) to install the 1,1'-difluoroolefin, which limits the scale at which the reaction can be carried out. In addition, existing syntheses rely on the introduction of cyclopentene by selenoxide elimination. Protected CPP-115 is selenylated in 70% yield, although the yield can vary depending on the scale. α-elimination of compound A produces a mixture of chromatographically inseparable isomers in a 5:3 ratio, favoring (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid. Compound B is selectively degraded using thiosalicylic acid to produce isolated (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid from compound A in a 36% overall yield. Only small batches of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid can be obtained using existing technology. In addition, since selenium is toxic and is regulated by the FDA to levels below 80 μg / day to 150 μg / day, the production of selenol in the penultimate step complicates the synthesis and purification of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid.

[0012] Therefore, there is a need for a process more suitable for the large-scale preparation of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid that will reduce costs, reduce the number of preparation steps, reduce harmful environmental waste, and improve preparation efficiency.

[0013] Overview

[0014] Provided is a process for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a salt thereof, the process comprising converting (1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one (2) into (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) and converting (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) into (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4). (1R,4R,6S,7R)-7-Bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) was converted to (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (25). (1R,4R,6S,7R)-7-Bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (25) was converted to (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5). (1R,4R,7R)-7-Bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5) was converted to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6). (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6) was converted to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]hept-3-one (7). (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) is converted to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8). (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) is converted to (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9). Methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) is converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1).

[0015] (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) is prepared by the process described herein. Compositions comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) are described herein. Pharmaceutical compositions comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) are described herein.

[0016] Provided herein are (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3). Provided herein are compositions comprising (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3). Provided herein are pharmaceutical compositions comprising (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3). (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) is prepared by the process disclosed herein.

[0017] Provided herein are (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4). Provided herein are compositions comprising (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4). Provided herein are pharmaceutical compositions comprising (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4). (1R,4R,6S,7R)-7-Bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) was prepared by the process disclosed herein.

[0018] Provided herein are (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25). Provided herein are compositions comprising (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25). Provided herein are pharmaceutical compositions comprising (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25). (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25) are prepared by the processes disclosed herein.

[0019] Provided herein are (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5). Provided herein are compositions comprising (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5). Provided herein are pharmaceutical compositions comprising (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5). (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) is prepared by the processes described herein.

[0020] Provided herein are (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6). Provided herein are compositions comprising (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6). Provided herein are pharmaceutical compositions comprising (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6). (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) is prepared by the processes described herein.

[0021] Provided herein are (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7). Provided herein are compositions comprising (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7). Provided herein are pharmaceutical compositions comprising (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7). (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) is prepared by the processes described herein.

[0022] Provided herein are (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8). Provided herein are compositions comprising (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8). Provided herein are pharmaceutical compositions comprising (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8). (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) are prepared by the processes described herein.

[0023] Provided herein is (S)-methyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9). Provided herein are compositions comprising methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9). Provided herein are pharmaceutical compositions comprising methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9). Methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) is prepared by the processes described herein.

[0024] Provided herein are (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19). Provided herein are compositions comprising (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19). Provided herein are pharmaceutical compositions comprising (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19). (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) is prepared by the processes described herein.

[0025] Provided are compositions comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) and (1S,3S)-3-amino-4-(difluoromethylene)cyclopentane-1-carboxylic acid. Provided are pharmaceutical compositions comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) and (1S,3S)-3-amino-4-(difluoromethylene)cyclopentane-1-carboxylic acid.

[0026] Provided are compositions comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) and one or more of: (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3), (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4), (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (25), (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3, 6-diketone (5), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7), (1R,4R,7R)-7-bromo-6- (Difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8), (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9), or (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19).

[0027] Provided is a process for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1), the process comprising converting cyclopent-3-ene-carboxylic acid ethyl ester (10) into (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11). Converting (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11) into (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12). Converting (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester into (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (13). Ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) was converted to ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14). Ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14) was converted to ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15). (S)-Ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) was converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1).

[0028] Provided herein is ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11). Provided herein are compositions comprising ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11). Provided herein are pharmaceutical compositions comprising ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11). Ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11) is prepared by the processes described herein.

[0029] Provided herein is (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12). Provided herein are compositions comprising (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12). Provided herein are pharmaceutical compositions comprising (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12). (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12) is prepared by the processes described herein.

[0030] Provided herein is ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13). Provided herein are compositions comprising ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13). Provided herein are pharmaceutical compositions comprising ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13). Ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) is prepared by the processes described herein.

[0031] Provided herein is (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14). Provided herein are compositions comprising (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14). Provided herein are pharmaceutical compositions comprising (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14). (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14) is prepared by the processes described herein.

[0032] Provided herein is (S)-ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15). Provided herein are compositions comprising (S)-ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15). Provided herein are pharmaceutical compositions comprising (S)-ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15). Ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) is prepared by the processes described herein.

[0033] Provided are compositions comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) and one or more of cyclopent-3-ene-carboxylic acid ethyl ester (10), (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11), (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12), (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (13), (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14) or (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid ethyl ester (15). BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The 500 MHz of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) 1 H NMR spectroscopy (CDCl3).

[0035] Figure 2 (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) 13 C NMR spectroscopy (CDCl3; 126 MHz).

[0036] Figure 3 The 127.5 MHz signal of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) 19 F NMR spectrum (CDCl3).

[0037] Figure 4 The 500 MHz of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) 1 H NMR spectroscopy (CDCl3).

[0038] Figure 5 (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) 13 CNMR spectroscopy (CDCl3; 126 MHz).

[0039] Figure 6The 127.5 MHz signal of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) 19 F NMR spectrum (CDCl3).

[0040] Figure 7 is the 500 MHz of (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9) 1 H NMR spectroscopy (CDCl3).

[0041] Figure 8 is (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9) 13 C NMR spectroscopy (CDCl3; 126 MHz).

[0042] Figure 9 is 127.5 MHz for (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9) 19 F NMR spectroscopy.

[0043] Figure 10 is the 500 MHz of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) 1 H NMR spectroscopy (CDCl3).

[0044] Figure 11 (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) 13 C NMR spectroscopy (CDCl3; 126 MHz).

[0045] Figure 12 is the 127.5 MHz of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) 19 F NMR spectroscopy.

[0046] Details

[0047] Provided herein are processes, compounds, and compositions for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1). Compared to the prior art, the processes herein are scalable and high-yielding, avoid the use of selenium and tert-butyllithium, and avoid the formation of multiple isomers from α-elimination. In embodiments, the processes herein include elimination of a leaving group from the β-position, exclude the resulting isomer mixture, reduce the number of synthetic steps from 14 to 9, and increase the yield from 3.7% to 8.1%, compared to the prior art.

[0048] In an embodiment, the synthesis of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) is shown in Scheme 1, starting with ((1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one) (2).

[0049] Solution 1

[0050]

[0051] AC = acetyl, PMB = 4-methoxybenzyl, PG = protecting group

[0052] According to Scheme 1, a process for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a salt thereof is provided, which comprises converting ((1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one) (2) into (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3). Converting (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) into (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4). (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) is converted to (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5). (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5) is converted to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6). (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) was converted to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7). (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) was converted to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (8). (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) is converted into (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9). (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9) is converted into (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1).

[0053] In an embodiment, the synthesis of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) is shown in Scheme 1A.

[0054] Option 1A

[0055]

[0056] Abbreviations: PMBOH: 4-methoxybenzyl alcohol; DMF: NN-dimethylformamide; DBDMH: 1,3-dibromo-5,5-dimethylhydantoin; TPAP: tetrapropylammonium perruthenate; NMO: N-methylmorpholine N-oxide; CAN: ceric ammonium nitrate; DMAP: N,N-dimethylaminopyridine

[0057] In an embodiment, starting from ((1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one) (2) (also known as Vince lactam) and following modifications of literature procedures, such as using PMBOH / HCl (see, Qiu, J.; Silverman, RBJ Med. Chem. 2000, 43, 706-720), (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) (Scheme 1A) is obtained on a multi-gram scale: a. PMBOH, HCl, NaH, THF / DMF; b. DBDMH, AcOH. Alcoholysis and oxidation of the acetate yielded the ketone (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) in two steps: c. K2CO3, alcohol; d. TPAP, NMO, MS, CH2Cl2. The above allows the difluoro-Horner-Wadsworth-Emmons olefination of ketone 5. When 2-((difluoromethyl)sulfinyl)pyridine (20) (also known as Hu reagent) is reacted with KO as a base t When used together with Bu, (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) was obtained: e. 2-((difluoromethyl)sulfinyl)pyridine (20), KO tBu, DMF, then NH4Cl, then HCl. Alternatively, e. can be tert-butyllithium and F2CHP(O)(OEt)2 (see, Pan, Y.; Qiu, J.; Silverman, RBJ Med. Chem. 2003, 46, 5292-5293). The next step is alcoholysis and elimination of the lactam. (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) is deprotected to produce (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7): f. CAN, MeCN, H2O. A small amount of 4-methoxybenzoyl-protected lactam can also be isolated. Boc protection of the lactam (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) yields (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8): g. Boc2O, DMAP, Et3N, CH2Cl2. Alcoholysis of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) with KCO and an alcohol results in subsequent elimination of the bromide over two steps to produce (S)-methyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate or ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9): h. KCO, alcohol. Final deprotection in HCl yields (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) without observable isomerization or degradation: i. HCl, dioxane. Although methanol is shown in the above scheme, it should be understood that alcohols such as ethanol or propanol can be used as the alcohol.

[0058] In embodiments, starting from ((1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one) (2) (Vince lactam) and following modifications of literature procedures (see, Qiu et al. supra), (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) is obtained on a multigram scale using PMBOH / HCl (Scheme 1A): a. PMBOH (1-2 equiv), HCl, NaH (0.8-1.5 equiv) at 0°C. ℃, THF / DMF (0.75-1.5:0.75-1.5), 4h-8h; b. DBDMH (0.4-0.8 equiv), AcOH, 15℃-30℃, 4h-8h; methanolysis and oxidation of the acetate in two steps to produce the ketone (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5): c. K2CO3 (2-4 equiv), MeOH0.5h-2h; d. TPAP (0.001-0.2 equiv), NMO (1.0-3.0 equiv), MS, CH2Cl2, 15h-25h. The above allows the difluoro-Horner-Wadsworth-Emmons olefination of ketone 5. When 2-((difluoromethyl)sulfinyl)pyridine (20) (Hu reagent) is reacted with KO as a base t When used together with Bu, (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) is obtained, for example, by quenching with NH4Cl / 6MHCl and injecting the base within 15 minutes to 2 hours: e. 2-((difluoromethyl)sulfinyl)pyridine (20) (1.0-1.5 equivalents), KO tBu (1.25-1.75 equiv), DMF, -80°C-40°C, 15 min-60 min, then NH4Cl, then HCl, then 15°C-30°C, then 40°C-80°C, 1 h. Alternatively, e. can be tert-butyllithium and F2CHP(O)(OEt)2 (see, Pan, Y. et al. supra). The next step is methanolysis and elimination of the lactam. Deprotection of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) to yield (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7): f. CAN (2-4 equiv), MeCN, H2O, -10°C to 10°C, 0.75h-2h. A small amount of the 4-methoxybenzoyl-protected lactam can also be isolated. Boc protection of lactam (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one) (7) yields (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8): g. Boc2O (1.0-1.5 equiv), DMAP (0.01-0.5 equiv), Et3N (1.0-2.0 equiv), CH2Cl2, 0.5h-2.0h. Methanolysis of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) with KCO and methanol resulted in subsequent elimination of the bromide over two steps to yield (S)-methyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate: h. KCO (2-4 equiv), MeOH, 4h-8h. Final deprotection in 6M HCl at 70°C-90°C yielded (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) with no observable isomerization or degradation: i. HCl (6M), dioxane, 70°C-90°C, 1h-3h.

[0059] In embodiments, starting from ((1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one) (2) (Vince lactam) and following modifications of literature procedures, such as using PMBOH / HCl (see, Qiu, J., et al. supra), (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) is obtained on a multi-gram scale (Scheme 1A): a. PMBOH (11.5 equiv.) , HCl, NaH (1.1 equiv), 0°C, THF / DMF (1:1), 6 h, 73%; b. DBDMH (0.6 equiv), AcOH, 23°C, 6 h, 90%; methanolysis and oxidation of the acetate in two steps yielded the ketone (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5): c. K2CO3 (3 equiv), MeOH, 1 h; d. TPAP (0.01 equiv), NMO (2.0 equiv), MS, CH2Cl2, 18h, 52%. The above provides a format for running these steps on a multigram scale, allowing the difluoro-Horner-Wadsworth-Emmons olefination of ketone 5. When 2-((difluoromethyl)sulfinyl)pyridine (20) (Hu reagent) was reacted with KO as a base t Bu, when used together with the conditions reported by Hu (see, Zhao, Y.; Huang, W.; Zhu, L.; Hu, J. Org. Lett. 2010, 12, 1444-1447), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) was obtained in small amounts (<10% yield). Slow injection of base over 30 minutes and quenching with NH4Cl / 6MHCl significantly increased the yield to 45%. Extending the base injection to 1 hour increased the yield to 58%. See Table 1 below. The reaction was not greatly affected by scale, allowing for scale-up to 3.5 g of (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) with no loss in yield: e. 2-((difluoromethyl)sulfinyl)pyridine (20) (1.2 equiv), KO tBu (1.5 eq), DMF, -60°C, 30 min, then NH4Cl, then 6M HCl, then 23°C, then 60°C, 1 h. Alternatively, e. can be tert-butyllithium and F2CHP(O)(OEt)2 (see, Pan, et al., supra). The next step is methanolysis and elimination of the lactam. (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) is deprotected to give (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) in 80% yield: f. CAN (3 eq), MeCN, H2O, 0°C, 1 h. A small amount of the 4-methoxybenzoyl-protected lactam can also be isolated. Boc protection of lactam (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one) (7) yields (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8): g. Boc2O (1.2 equiv), DMAP (0.1 equiv), Et3N (1.5 equiv), CH2Cl2, 1h. Methanolysis of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) with KCO and methanol resulted in subsequent elimination of the bromide to yield (S)-methyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9): h. KCO (3 eq), MeOH, 6 h, 52% over two steps. Final deprotection in 6 M HCl at 80° C. yielded (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) in 97% yield with no observable isomerization or degradation: i. HCl (6 M), dioxane, 80° C., 2 h. Overall, the yield of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) from Vince lactam (2) was 8.1%.

[0060] Table 1. Fluorination a Optimization

[0061]

[0062]

[0063]

[0064] aConditions: 5 (1 eq), 20 (1.2 eq), DMF (0.3 M), -60 °C, then KO in DMF t Bu (1.5 eq.) (0.5 M), then quenched at -60 °C, then 23 °C, then 60 °C for 1 h; b time before addition of the quenching solution; c Yield of isolation after chromatography.

[0065] In embodiments, without wishing to be bound by any theory, the following is a proposed mechanism for the fluorination of (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5):

[0066]

[0067] As shown above, multiple intermediates are formed during the fluorination reaction process. The first formed intermediate 21 rearranges via the cyclic intermediate 22 to form the sulfonate 23, which is then protonated, triggering the elimination and formation of the olefin (see above). t 5 min after Bu, the reaction was quenched with 6M HCl at -60°C and only 21 was observed by LC / MS (entry 1, Table 1). t Bu, followed by 6M HCl quenching at -60°C (entry 2, Table 1), and subsequently heating at 60°C for 1 h, provided 6 in 9% yield along with starting material and intermediate 21. After quenching with saturated NH4Cl solution for 1 hour, followed by quenching with 6M HCl, the yield was slightly improved (entry 3, Table 1). Slowly injecting the base with a syringe pump over 30 min, quenching with NH4Cl / 6M HCl, significantly increased the yield to 45%. Extending the injection of the base to 1 hour increased the yield to 58%.

[0068] In an embodiment, the synthesis of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) is shown in Scheme 2.

[0069] Option 2

[0070]

[0071] Racemic synthesis yields (%) are given relative to (s)-isomer yields (%).

[0072] Abbreviations: LiHMDS: lithium bis(trimethylsilyl)amide; THF: tetrahydrofuran; PMB: 4-methoxybenzyl; DBDMH: 1,3-dibromo-5,5-dimethylhydantoin; TPAP: tetrapropylammonium perruthenate; CAN: ceric ammonium nitrate; DMAP: N,N-dimethylaminopyridine

[0073] According to Scheme 2, a process for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a salt thereof is provided, which comprises converting ((1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one) (2) into (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3). Converting (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) into (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4). (1R,4R,6S,7R)-7-Bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) was converted to (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (25). (1R,4R,6S,7R)-7-Bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (25) was converted to (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5). (1R,4R,7R)-7-Bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5) was converted to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6). (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6) was converted to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]hept-3-one (7). (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) was converted to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8). (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) was converted to (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19).(S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) is converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1).

[0074] In an embodiment, the following compounds are provided:

[0075]

[0076] (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3)

[0077]

[0078] (1R,4R,6S,7R)-7-Bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4)

[0079]

[0080] (1R,4R,6S,7R)-7-Bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25)

[0081]

[0082] (1R,4R,7R)-7-Bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5)

[0083]

[0084] (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6)

[0085]

[0086] (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7)

[0087]

[0088] (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8)

[0089]

[0090] (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9)

[0091]

[0092] (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19)

[0093] In an embodiment, provided herein are compositions comprising (1R, 4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising (1R, 4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) or a salt thereof may comprise a polar solvent, such as aqueous, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. Compositions comprising (1R, 4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may contain (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0. 0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.008mg mg, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0.3mg or 9.0 mg to 10 mg.

[0094] In embodiments, provided herein are compositions comprising (1R, 4R, 6S, 7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising (1R, 4R, 6S, 7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as diethyl ether, hexane, dichloromethane, ethyl acetate, or the like. The composition containing (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) or a pharmaceutically acceptable salt thereof can be a pharmaceutical composition. The composition can contain (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, for example, from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005mg to 0.0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg g to 0.008 mg, 0.008 mg to 0.009 mg, 0.009 mg to 0.01 mg, 0.01 mg to 0.02 mg, 0.02 mg to 0.03 mg, 0.03 mg to 0.04 mg, 0.04 mg to 0.05 mg, 0.05 mg to 0.06 mg, 0.06 mg to 0.07 mg, 0.07 mg to 0.08 mg, 0.08 mg to 0.09 mg, 0.09 mg to 0.1 mg, 0.1 mg to 0.2 mg, 0.2 mg to 0.3 mg, 0.3 mg to 0.4 mg, 0.4 mg to 0.5 mg, 0.5 mg to 0.6 mg, 0.6 mg to 0.7 mg, 0.7 mg to 0.8 mg, 0.8 mg to 0.9 mg, 0.9 mg to 1.0 mg, 1.0 mg to 2.0 mg, 2.0 mg to 3.0 mg, 3.0 mg to 4.0 mg, 4.0 mg to 5.0 mg, 5.0 mg to 6.0 mg, 6.0 mg to 7.0 mg, 7.0 mg to 8.0 mg, 8.0 mg to 9.0 mg or 9.0 mg to 10 mg.

[0095] In embodiments, provided herein are compositions comprising (1R, 4R, 6S, 7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising (1R, 4R, 6S, 7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. The composition comprising (1R, 4R, 6S, 7R) -7-bromo-6-hydroxy-2- (4-methoxybenzyl) -2-azabicyclo [2.2.1] heptan-3-one (25) or a pharmaceutically acceptable salt thereof can be a pharmaceutical composition. The composition can contain (1R, 4R, 6S, 7R) -7-bromo-6-hydroxy-2- (4-methoxybenzyl) -2-azabicyclo [2.2.1] heptan-3-one (25) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0006 mg to 0.0007 mg, 0.0008 mg to 0.0009 mg, 0.0010 mg to 0.0011 mg, 0.0011 mg to 0.0012 mg, 0.0013 mg to 0.0014 mg, 0.0015 mg to 0.0016 mg, 0.0017 mg to 0.0018 mg, 0.0019 mg to 0.0021 mg, 0.0011 mg to 0.0019 mg, 0.0011 mg to 0.0017 mg, 0.0011 mg to 0.0018 mg, 0.0011 mg to 0.0019 ... 0.0005mg to 0.0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.008mg, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0 0 mg, 0.3 mg to 0.4 mg, 0.4 mg to 0.5 mg, 0.5 mg to 0.6 mg, 0.6 mg to 0.7 mg, 0.7 mg to 0.8 mg, 0.8 mg to 0.9 mg, 0.9 mg to 1.0 mg, 1.0 mg to 2.0 mg, 2.0 mg to 3.0 mg, 3.0 mg to 4.0 mg, 4.0 mg to 5.0 mg, 5.0 mg to 6.0 mg, 6.0 mg to 7.0 mg, 7.0 mg to 8.0 mg, 8.0 mg to 9.0 mg or 9.0 mg to 10 mg.

[0096] In embodiments, provided herein are compositions comprising (1R, 4R, 7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising (1R, 4R, 7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. Compositions comprising (1R, 4R, 7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may contain (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0.0006 mg, 0.0006 mg to 0.0007 mg, 0.0008 mg to 0.0009 mg, 0.0010 mg to 0.0011 mg, 0.0011 mg to 0.0012 mg, 0.0011 mg to 0.0013 mg, 0.0012 mg to 0.0014 mg, 0.0011 mg to 0.0015 mg, 0.0011 mg to 0.0016 mg, 0.0011 mg to 0.0017 mg, 0.0011 mg to 0.0018 mg, 0.0011 mg to 0.0019 mg, 0.0012 mg to 0.0018 mg, 0.0011 mg to 0.0019 mg, 0.0011 mg to 0.0019 mg, 0.0011 mg to 0.001 mg to 0.0006 mg, 0.0006 mg to 0.0007 mg, 0.0007 mg to 0.0008 mg, 0.0008 mg to 0.0009 mg, 0.0009 mg to 0.001 mg, 0.001 mg to 0.002 mg, 0.002 mg to 0.003 mg, 0.003 mg to 0.004 mg, 0.004 mg to 0.005 mg, 0.005 mg to 0.006 mg, 0.006 mg to 0.007 mg, 0.007 mg to 0. 008mg, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0. 3mg to 0.4mg, 0.4mg to 0.5mg, 0.5mg to 0.6mg, 0.6mg to 0.7mg, 0.7mg to 0.8mg, 0.8mg to 0.9mg, 0.9mg to 1.0mg, 1.0mg to 2.0mg, 2.0mg to 3.0mg, 3.0mg to 4.0mg, 4.0mg to 5.0mg, 5.0mg to 6.0mg, 6.0mg to 7.0mg, 7.0mg to 8.0mg, 8.0mg to 9.0mg or 9.0mg to 10mg.

[0097] In embodiments, provided herein are compositions comprising (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as diethyl ether, hexane, dichloromethane, ethyl acetate, or the like. The composition containing (1R, 4R, 7R) -7-bromo-6- (difluoromethylene) -2- (4-methoxybenzyl) -2-azabicyclo [2.2.1] heptan-3-one (6) or a pharmaceutically acceptable salt thereof can be a pharmaceutical composition. The composition can contain (1R, 4R, 7R) -7-bromo-6- (difluoromethylene) -2- (4-methoxybenzyl) -2-azabicyclo [2.2.1] heptan-3-one (6) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, for example, from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0006 mg to 0.0007 mg, 0.0008 mg to 0.0009 mg, 0.0010 mg to 0.0011 mg, 0.0011 mg to 0.0012 mg, 0.0012 mg to 0.0013 mg, 0.0014 mg to 0.0015 mg, 0.0016 mg to 0.0017 mg, 0.0017 mg to 0.0018 mg, 0.0019 mg to 0.0021 mg, 0.0018 mg to 0.0022 mg, 0.0019 mg to 0.0023 mg, 0.0019 mg to 0.0024 mg, 0.0019 mg to 0.0025 mg, 0.0019 mg to 0.0026 mg, 0.0019 mg to 0.0027 mg 0.0005mg to 0.0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg g to 0.008 mg, 0.008 mg to 0.009 mg, 0.009 mg to 0.01 mg, 0.01 mg to 0.02 mg, 0.02 mg to 0.03 mg, 0.03 mg to 0.04 mg, 0.04 mg to 0.05 mg, 0.05 mg to 0.06 mg, 0.06 mg to 0.07 mg, 0.07 mg to 0.08 mg, 0.08 mg to 0.09 mg, 0.09 mg to 0.1 mg, 0.1 mg to 0.2 mg, 0.2 mg to 0.3 mg, 0.3 mg to 0.4 mg, 0.4 mg to 0.5 mg, 0.5 mg to 0.6 mg, 0.6 mg to 0.7 mg, 0.7 mg to 0.8 mg, 0.8 mg to 0.9 mg, 0.9 mg to 1.0 mg, 1.0 mg to 2.0 mg, 2.0 mg to 3.0 mg, 3.0 mg to 4.0 mg, 4.0 mg to 5.0 mg, 5.0 mg to 6.0 mg, 6.0 mg to 7.0 mg, 7.0 mg to 8.0 mg, 8.0 mg to 9.0 mg or 9.0 mg to 10 mg.

[0098] In embodiments, provided herein are compositions comprising (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. Compositions comprising (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may contain (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, for example, from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0.0006 mg. 0.0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.00 8mg, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0.3 or 9.0 mg to 10 mg.

[0099] In embodiments, provided herein are compositions comprising (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as diethyl ether, hexane, dichloromethane, ethyl acetate, or the like. The composition comprising (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) or a pharmaceutically acceptable salt thereof may be a pharmaceutical composition. The composition may comprise (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0006 mg to 0.0007 mg, 0.0008 mg to 0.0009 mg, 0.0010 mg to 0.0011 mg, 0.0011 mg to 0.0012 mg, 0.0011 mg to 0.0013 mg, 0.0012 mg to 0.0014 mg, 0.0013 mg to 0.0015 mg, 0.0016 mg to 0.0017 mg, 0.0017 mg to 0.0018 mg, 0.0019 mg to 0.0021 mg, 0.0019 mg to 0.0023 mg, 0.0019 mg to 0.0024 mg, 0.0019 mg to 0.0025 mg, 0.0019 mg to 0.0026 mg, 0.0019 mg to 0.0027 mg, 0.0019 mg to 0.0026 mg, 0.0019 mg to 0.0027 mg 0.0005mg to 0.0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.008mg, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0 0 mg, 0.3 mg to 0.4 mg, 0.4 mg to 0.5 mg, 0.5 mg to 0.6 mg, 0.6 mg to 0.7 mg, 0.7 mg to 0.8 mg, 0.8 mg to 0.9 mg, 0.9 mg to 1.0 mg, 1.0 mg to 2.0 mg, 2.0 mg to 3.0 mg, 3.0 mg to 4.0 mg, 4.0 mg to 5.0 mg, 5.0 mg to 6.0 mg, 6.0 mg to 7.0 mg, 7.0 mg to 8.0 mg, 8.0 mg to 9.0 mg or 9.0 mg to 10 mg.

[0100] In embodiments, provided herein are compositions comprising methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. Compositions comprising methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may contain methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0.0006 mg. 0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.008mg mg, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0.3mg or 9.0 mg to 10 mg.

[0101] In embodiments, provided herein are compositions comprising (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. Compositions comprising (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may contain (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may comprise the following amount of (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, for example, from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0.0 006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.008mg g, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0.3mg or 9.0 mg to 10 mg.

[0102] In an embodiment, the synthesis of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) is shown in Scheme 3, starting with cyclopent-3-ene-carboxylic acid ethyl ester (10).

[0103] Option 3

[0104]

[0105] As depicted in Scheme 3, a process for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) is provided, which comprises converting cyclopent-3-ene-carboxylic acid ethyl ester (10) into (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11). (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11) is converted into (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12). (3R)-3-((tert-Butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester was converted to (9S)-9-(tert-Butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (13). (9S)-9-(tert-Butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (13) was converted to (S)-9-(tert-Butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14). Ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14) was converted to ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15). Ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) was converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1).

[0106] In an embodiment, the synthesis of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) is shown in Scheme 3A.

[0107] Option 3A

[0108]

[0109] In an embodiment, as shown in Scheme 3A, cyclopent-3-ene-carboxylic acid ethyl ester (10) (commercially available from Sigma Aldrich, St. Louis, MO) is converted to (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11) by Sharpless aminohydroxylation and Boc protection. Sharpless aminohydroxylation allows the synthetic selective preparation of 1,2-amino alcohols by reaction of olefins with salts of N-halosulfonamides, salts of N-haloamides, and salts of N-halocarbamates using OsO4 as a catalyst. Enantioselectivity is achieved by the addition of dihydroquinine-derived and dihydroquinidine-derived chiral ligands. Oxidation of ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11) yields the ketone ethyl (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylate (12). Ethyl (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylate (12) is converted to ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13). Ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) is subjected to phenylselenium bromide, base, and H2O2 to produce ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14). Ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14) is deprotected and subjected to a Horner-Wittig reaction to produce ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15). The Horner-Wittig reaction involves the reaction of an aldehyde or ketone with a stable phosphonium ylide (phosphonate carbanion) and leads to an olefin with E-selectivity. (S)-Ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) was converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) using trifluoroacetic acid (TFA), dichloromethane (DCM) and saturated NaHCO3.

[0110] In an embodiment, the following compounds are provided:

[0111]

[0112] Ethyl (3R,4S)-3-((tert-Butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11)

[0113]

[0114] (3R)-3-((tert-Butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12)

[0115]

[0116] Ethyl (9S)-9-(tert-Butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13)

[0117]

[0118] (S)-9-(tert-Butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14)

[0119]

[0120] (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid ethyl ester (15)

[0121] In embodiments, provided herein are compositions comprising ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, etc.; or a non-polar solvent, such as diethyl ether, hexane, dichloromethane, ethyl acetate, etc. Compositions comprising ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may contain ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0.0006 mg. 6mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.008mg , 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0.3mg to 0.4 mg, 0.4 mg to 0.5 mg, 0.5 mg to 0.6 mg, 0.6 mg to 0.7 mg, 0.7 mg to 0.8 mg, 0.8 mg to 0.9 mg, 0.9 mg to 1.0 mg, 1.0 mg to 2.0 mg, 2.0 mg to 3.0 mg, 3.0 mg to 4.0 mg, 4.0 mg to 5.0 mg, 5.0 mg to 6.0 mg, 6.0 mg to 7.0 mg, 7.0 mg to 8.0 mg, 8.0 mg to 9.0 mg or 9.0 mg to 10 mg.

[0122] In embodiments, provided herein are compositions comprising ethyl (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylate (12) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising ethyl (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylate (12) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. Compositions comprising ethyl (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylate (12) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may comprise ethyl (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylate (12) or a salt thereof in an amount from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0.0006 mg , 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.008mg, 0 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0.3mg to 0.4 mg, 0.4 mg to 0.5 mg, 0.5 mg to 0.6 mg, 0.6 mg to 0.7 mg, 0.7 mg to 0.8 mg, 0.8 mg to 0.9 mg, 0.9 mg to 1.0 mg, 1.0 mg to 2.0 mg, 2.0 mg to 3.0 mg, 3.0 mg to 4.0 mg, 4.0 mg to 5.0 mg, 5.0 mg to 6.0 mg, 6.0 mg to 7.0 mg, 7.0 mg to 8.0 mg, 8.0 mg to 9.0 mg or 9.0 mg to 10 mg.

[0123] In embodiments, provided herein are compositions comprising ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. Compositions comprising ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may contain ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0. 0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.008mg mg, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0.3mg or 9.0 mg to 10 mg.

[0124] In embodiments, provided herein are compositions comprising ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. Compositions comprising ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may contain ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may comprise the following amount of (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0.0006 mg. 0.0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.00 8mg, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0.3 or 9.0 mg to 10 mg.

[0125] In embodiments, provided herein are compositions comprising ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) or a salt thereof. Such compositions may comprise a reaction mixture, such as those described herein. Compositions comprising ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) or a salt thereof may comprise a polar solvent, such as water, methanol, ethanol, DMF, acetic acid, or the like; or a non-polar solvent, such as ether, hexane, dichloromethane, ethyl acetate, or the like. Compositions comprising ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) or a pharmaceutically acceptable salt thereof may be pharmaceutical compositions. The composition may contain ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) or a salt thereof in an amount of from 0.0001 mg to 50 mg or more.For example, the pharmaceutical composition may contain the following amount of (S)-ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) or a pharmaceutically acceptable salt thereof: greater than 0.0001 mg, such as from 0.0001 mg to 0.0002 mg, 0.0001 mg to 0.0003 mg, 0.0002 mg to 0.0003 mg, 0.0003 mg to 0.0004 mg, 0.0004 mg to 0.0005 mg, 0.0005 mg to 0.0006 mg. 0006mg, 0.0006mg to 0.0007mg, 0.0007mg to 0.0008mg, 0.0008mg to 0.0009mg, 0.0009mg to 0.001mg, 0.001mg to 0.002mg, 0.002mg to 0.003mg, 0.003mg to 0.004mg, 0.004mg to 0.005mg, 0.005mg to 0.006mg, 0.006mg to 0.007mg, 0.007mg to 0.008mg mg, 0.008mg to 0.009mg, 0.009mg to 0.01mg, 0.01mg to 0.02mg, 0.02mg to 0.03mg, 0.03mg to 0.04mg, 0.04mg to 0.05mg, 0.05mg to 0.06mg, 0.06mg to 0.07mg, 0.07mg to 0.08mg, 0.08mg to 0.09mg, 0.09mg to 0.1mg, 0.1mg to 0.2mg, 0.2mg to 0.3mg, 0.3mg or 9.0 mg to 10 mg.

[0126] In an embodiment, the pharmaceutical composition may comprise (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid or a pharmaceutically acceptable salt thereof in an amount of, for example, about 0.001 mg to 500 mg, 0.01 mg to 500 mg, 0.01 mg to 450 mg, 0.01 mg to 300 mg, 0.01 mg to 250 mg, 0.01 mg to 200 mg, 0.01 mg to 175 mg, 0.01 mg to 150 mg, 0.01 mg to 125 mg, 0.01 mg to 100 mg, 0.01 mg to 75 mg, 0.01 mg to 50 mg, 0.01 mg to 30 mg, 0.01 mg to 25 mg, 0.01 mg to 30 mg. g to 20 mg, 0.01 mg to 15 mg, 0.01 mg to 10 mg, 0.01 mg to 5 mg, 0.01 mg to 1 mg, 0.025 mg to 500 mg, 0.025 mg to 450 mg, 0.025 mg to 300 mg, 0.025 mg to 250 mg, 0.025 mg to 200 mg, 0.025 mg to 175 mg, 0.025 mg to 150 mg, 0.025 mg to 125 mg, 0.025 mg to 100 mg, 0.025 mg to 75 mg, 0.025 mg to 50 mg, 0.025 mg to 30 mg, 0.025 mg to 25 mg, 0.025 mg to 20 mg, 0.025 mg to 15mg, 0.025mg to 10mg, 0.025mg to 5mg, 0.025mg to 1mg, 0.05mg to 500mg, 0.05mg to 450mg, 0.05mg to 300mg, 0.05mg to 250mg, 0.05mg to 200mg, 0.05mg to 175mg, 0.05mg to 150mg, 0.05mg to 125mg, 0.05mg to 100mg, 0.05mg to 75mg, 0.05mg to 50mg, 0.05mg to 30mg, 0.05mg to 25mg, 0.05mg to 20mg, 0.05mg to 15mg, 0.05mg to 10mg, 0. 0.05mg to 5mg, 0.05mg to 1mg, 0.075mg to 500mg, 0.075mg to 450mg, 0.075mg to 300mg, 0.075mg to 250mg, 0.075mg to 200mg, 0.075mg to 175mg, 0.075mg to 150mg, 0.075mg to 125mg, 0.075mg to 100mg, 0.075mg to 75mg, 0.075mg to 50mg, 0.075mg to 30mg, 0.075mg to 25mg, 0.075mg to 20mg, 0.075mg to 15mg, 0.075mg to 10mg, 0.075mg to 5mg,0.075mg to 1mg, 0.1mg to 500mg, 0.1mg to 450mg, 0.1mg to 300mg, 0.1mg to 250mg, 0.1mg to 200mg, 0.1mg to 175mg, 0.1mg to 150mg, 0.1mg to 125mg, 0.1mg to 100mg, 0.1mg to 75mg, 0.1mg to 50mg, 0.1mg to 30mg, 0.1mg to 25mg, 0.1mg to 20mg, 0.1mg to 15mg, 0.1mg to 10mg, 0.1mg to 5mg, 0.1mg to 1mg, 0.25mg g to 500mg, 0.25mg to 450mg, 0.25mg to 300mg, 0.25mg to 250mg, 0.25mg to 200mg, 0.25mg to 175mg, 0.25mg to 150mg, 0.25mg to 125mg, 0.25mg to 100mg, 0.25mg to 75mg, 0.25mg to 50mg, 0.25mg to 30mg, 0.25mg to 25mg, 0.25mg to 20mg, 0.25mg to 15mg, 0.25mg to 10mg, 0.25mg to 5mg, 0.25mg to 1mg, 0.5mg to 500mg, 0.5mg to 450mg, 0.5mg to 300mg, 0.5mg to 250mg, 0.5mg to 200mg, 0.5mg to 175mg, 0.5mg to 150mg, 0.5mg to 125mg, 0.5mg to 100mg, 0.5mg to 75mg, 0.5mg to 50mg, 0.5mg to 30mg, 0.5mg to 25mg, 0.5mg to 20mg, 0.5mg to 15mg, 0.5mg to 10mg, 0.5mg to 5mg, 0.5mg to 1mg, 1mg to 500mg, 1mg to 450mg, 1mg to 300mg, 1mg to 250mg, 1mg to 200mg, 1mg to 175mg, 1mg to 150mg, 1mg to 125mg, 1mg to 100mg, 1mg to 75mg, 1mg to 50mg, 1mg to 30mg, 1mg to 25mg, 1mg to 20mg, 1mg to 15mg, 1mg to 10mg, 1mg to 5mg, 1mg to 4mg, 1mg to 3mg, 1mg to 2mg, 2mg to 500mg, 2mg to 450mg, 2mg to 300mg, 2mg to 250mg, 2mg to 200mg, 2mg to 175mg, 2mg to 500mg mg to 150mg, 2mg to 125mg, 2mg to 100mg, 2mg to 75mg, 2mg to 50mg, 2mg to 30mg, 2mg to 25mg, 2mg to 20mg, 2mg to 15mg, 2mg to 10mg, 2mg to 5mg,3mg to 500mg, 3mg to 450mg, 3mg to 300mg, 3mg to 250mg, 3mg to 200mg, 3mg to 175mg, 3mg to 150mg, 3mg to 125mg, 3mg to 100mg, 3mg to 75mg, 3mg to 50mg, 3mg to 30mg, 3mg to 25mg, 3mg to 20mg, 3mg to 15mg, 3mg to 10mg, 3mg to 5mg, 4mg to 500mg, 4mg to 450mg, 4mg to 300mg, 4mg to 250mg, 4mg to 200mg, 4mg to 175mg, 4mg to 150mg, 4mg to 125mg, 4mg to 100mg g, 4mg to 75mg, 4mg to 50mg, 4mg to 30mg, 4mg to 25mg, 4mg to 20mg, 4mg to 15mg, 4mg to 10mg, 4mg to 5mg, 5mg to 500mg, 5mg to 450mg, 5mg to 300mg, 5mg to 250mg, 5mg to 200mg, 5mg to 175mg, 5mg to 150mg, 5mg to 125mg, 5mg to 100mg, 5mg to 75mg, 5mg to 50mg, 5mg to 30mg, 5mg to 25mg, 5mg to 20mg, 5mg to 15mg, 5mg to 10mg, 10mg to 500mg, 10mg to 450mg, 10 mg to 300 mg, 10 mg to 250 mg, 10 mg to 200 mg, 10 mg to 175 mg, 10 mg to 150 mg, 10 mg to 125 mg, 10 mg to 100 mg, 10 mg to 75 mg, 10 mg to 50 mg, 10 mg to 30 mg, 10 mg to 25 mg, 10 mg to 20 mg, 10 mg to 15 mg, 15 mg to 500 mg, 15 mg to 450 mg, 15 mg to 300 mg, 15 mg to 250 mg, 15 mg to 200 mg, 15 mg to 175 mg, 15 mg to 150 mg, 15 mg to 125 mg, 15 mg to 100 mg, 15 mg to 75 mg, 15 mg to 5 0mg, 15mg to 30mg, 15mg to 25mg, 15mg to 20mg, 20mg to 500mg, 20mg to 450mg, 20mg to 300mg, 20mg to 250mg, 20mg to 200mg, 20mg to 175mg, 20mg to 150mg, 20mg to 125mg, 20mg to 100mg, 20mg to 75mg, 20mg to 50mg, 20mg to 30mg, 20mg to 25mg, 25mg to 500mg, 25mg to 450mg, 25mg to 300mg, 25mg to 250mg, 25mg to 200mg, 25mg to 175mg, 25mg to 150mg,25mg to 125mg, 25mg to 100mg, 25mg to 80mg, 25mg to 75mg, 25mg to 50mg, 25mg to 30mg, 30mg to 500mg, 30mg to 450mg, 30mg to 300mg, 30mg to 250mg, 30mg to 200mg, 30mg to 175mg, 30mg to 150mg, 30mg to 125mg, 30mg to 100mg, 30mg to 75mg, 30mg to 50mg, 40mg to 500mg, 40mg to 4 50mg, 40mg to 400mg, 40mg to 250mg, 40mg to 200mg, 40mg to 175mg, 40mg to 150mg, 40mg to 125mg, 40mg to 100mg, 40mg to 75mg, 40mg to 50mg, 50mg to 500mg, 50mg to 450mg, 50mg to 300mg, 50mg to 250mg, 50mg to 200mg, 50mg to 175mg, 50mg to 150mg, 50mg to 125mg, 50mg to 100mg, 50mg to 75mg, 75mg to 500mg, 75mg to 450mg, 75mg to 300mg, 75mg to 250mg, 75mg to 200mg mg, 75mg to 175mg, 75mg to 150mg, 75mg to 125mg, 75mg to 100mg, 100mg to 500mg, 100mg to 450mg, 100mg to 300mg, 100mg to 250mg, 100mg to 200mg, 100mg to 175mg, 100mg to 150mg, 100mg to 125mg, 125mg to 500mg, 125mg to 450mg, 125mg to 300mg, 125mg to 250mg, 125mg to 200mg, 125mg to 175mg, 125mg to 150mg, 150mg to 500mg, 150mg to 450mg, 150mg to 300mg, 150mg to 250mg, 150mg to 200mg, 200mg to 500mg, 200mg to 450mg, 200mg to 300mg, 200mg to 250mg, 250mg to 500mg, 250mg to 450mg, 250mg to 300mg, 300mg to 500mg, 300mg to 450mg, 300mg to 400mg, 300mg to 350mg, 350mg to 500mg, 350mg to 450mg, 350mg to 400mg, 400mg to 500mg, 400mg to 450mg, of which 0.01mg, 0.025mg, 0.05mg, 0.075mg, 0.1mg, 0.25mg, 0.5mg, 0.75mg,1 mg, 2 mg, 2.5 mg, 3 mg, 4 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 17.5 mg, 20 mg, 22.5 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 125 mg, 150 mg, 175 mg, 200 mg, 225 mg, 250 mg, 275 mg, 300 mg, 325 mg, 350 mg, 375 mg, 400 mg, 425 mg, 450 mg, 475 mg, and 500 mg are examples.

[0127] In an embodiment, a pharmaceutical composition is provided comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) and one or more of the following: (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3), (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4), (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6- dione (5), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) or (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9).

[0128] In an embodiment, a pharmaceutical composition is provided comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) and one or more of the following: cyclopent-3-ene-carboxylic acid ethyl ester (10), (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11), (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12), Ethyl formate (12), ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13), ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14), or ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15).

[0129] In embodiments, (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid can be provided as an acid addition salt, a zwitterion hydrate, a zwitterion anhydrate, a hydrochloride or a hydrobromide salt, or as a zwitterion monohydrate. Acid addition salts include, but are not limited to, addition salts of maleic acid, fumaric acid, benzoic acid, ascorbic acid, succinic acid, oxalic acid, bismethylene salicylic acid, methanesulfonic acid, ethanedisulfonic acid, acetic acid, propionic acid, tartaric acid, salicylic acid, citric acid, gluconic acid, lactic acid, malic acid, mandelic acid, cinnamic acid, citraconic acid, aspartic acid, stearic acid, palmitic acid, itaconic acid, glycolic acid, pantothenic acid, p-aminobenzoic acid, glutamic acid, benzenesulfonic acid, or theophylline acetate, and 8-halotheophylline, such as 8-bromo-theophylline. In embodiments, addition salts of inorganic acids may be used, including but not limited to hydrochloric, hydrobromic, hydroiodic, sulfuric, sulfamic, phosphoric, or nitric acid addition salts.

[0130] In embodiments, (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3), (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4), (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2 .1]heptan-3-one (6), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) or (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9) can be provided as an acid addition salt, a zwitter ion hydrate, a zwitter ion anhydrate, a hydrochloride or hydrobromide salt or as a zwitter ion monohydrate. Acid addition salts include, but are not limited to, maleic, fumaric, benzoic, ascorbic, succinic, oxalic, bismethylene salicylic, methanesulfonic, ethanedisulfonic, acetic, propionic, tartaric, salicylic, citric, gluconic, lactic, malic, mandelic, cinnamic, citraconic, aspartic, stearic, palmitic, itaconic, glycolic, pantothenic, p-aminobenzoic, glutamic, benzenesulfonic or theophylline acetic acid addition salts, and 8-halogenated theophylline, such as 8-bromo-theophylline. In embodiments, addition salts of inorganic acids may be used, including but not limited to addition salts of hydrochloric, hydrobromic, hydroiodic, sulfuric, sulfamic, phosphoric or nitric acids.

[0131] In embodiments, cyclopent-3-ene-carboxylic acid ethyl ester (10), (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11), (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12), (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (13 ), (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14) or (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid ethyl ester (15) can be provided as an acid addition salt, a zwitterion hydrate, a zwitterion anhydrate, a hydrochloride or hydrobromide salt or as a zwitterion monohydrate. Acid addition salts include, but are not limited to, maleic, fumaric, benzoic, ascorbic, succinic, oxalic, bismethylene salicylic, methanesulfonic, ethanedisulfonic, acetic, propionic, tartaric, salicylic, citric, gluconic, lactic, malic, mandelic, cinnamic, citraconic, aspartic, stearic, palmitic, itaconic, glycolic, pantothenic, p-aminobenzoic, glutamic, benzenesulfonic or theophylline acetic acid addition salts, and 8-halogenated theophylline, such as 8-bromo-theophylline. In embodiments, addition salts of inorganic acids may be used, including but not limited to addition salts of hydrochloric, hydrobromic, hydroiodic, sulfuric, sulfamic, phosphoric or nitric acids.

[0132] In an embodiment, the pharmaceutical composition includes a variety of dosage forms, including conventional formulations and modified release formulations. Such pharmaceutical compositions can be suitable for any suitable route of administration, such as oral, rectal, nasal, ocular, pulmonary, vaginal, sublingual, transdermal, intravenous, intraarterial, intramuscular, intraperitoneal, and subcutaneous. Suitable dosage forms include tablets, capsules, oral solutions, eye drops, eye ointments, eye gels, powders, aerosols, transdermal forms such as topical liquids, patches, creams and ointments, parenteral formulations, and suppositories.

[0133] In embodiments, as previously mentioned, the pharmaceutical compositions herein can be provided with conventional release profiles or modified release profiles. Pharmaceutical compositions can be prepared using a pharmaceutically acceptable "carrier" comprising a material that is considered to be safe and effective. A "carrier" includes all components that are different from one or more active ingredients (active ingredients or ingredients) present in a pharmaceutical formulation. The term "carrier" includes, but is not limited to, diluents, binders, lubricants, disintegrants, fillers, and coating compositions. Those skilled in the art are familiar with such pharmaceutical carriers and methods of compounding pharmaceutical compositions using such carriers.

[0134] In an embodiment, the pharmaceutical composition herein is a modified release dosage form that provides a modified release profile. The modified release profile can present an immediate release profile, a delayed release profile, or an extended release profile. Conventional (or unmodified) release oral dosage forms such as tablets, capsules, suppositories, syrups, solutions, and suspensions typically release the drug into the mouth, stomach, or intestine as the tablet, capsule shell, or suppository dissolves, or in the case of syrups, solutions, and suspensions, when they are swallowed. The pattern of drug release from a modified release (MR) dosage form is intentionally altered from that of a conventional dosage form to achieve desired therapeutic goals and / or better patient compliance. Types of MR drug products include orally disintegrating dosage forms (ODDF) that provide immediate release, extended release dosage forms, delayed release dosage forms (e.g., enteric coated), and pulsatile release dosage forms.

[0135] ODDF is a solid dosage form comprising a pharmaceutical substance or active ingredient, which typically disintegrates rapidly within a few seconds when placed on the tongue. The disintegration time of ODDF is typically in the range of from one or two seconds to about one minute. ODDF is designed to disintegrate or dissolve rapidly after contact with saliva. This mode of administration can be beneficial for people who may have problems swallowing tablets, whether the problem is essentially due to physical weakness or mental illness. Some subjects suffering from eye disorders may exhibit such behavior. ODDF can provide rapid delivery of drugs to the bloodstream through the mucous membrane, resulting in rapid onset. Examples of ODDF include orally disintegrating tablets, capsules, and rapidly dissolving films and wafers.

[0136] Extended-release dosage form (ERDF) has extended release profile, and is compared with the dosing frequency presented by conventional dosage form such as solution or unmodified release dosage form, allows those dosage forms of dosing frequency reduction. ERDF provides a sustained drug action duration. Providing a suitable formulation for extended release profile is well known in the art. For example, the slowly released beads or granules (" beads " and " granules " are used interchangeably herein) of coating, wherein any compound described herein is applied to beads, such as confectionersnonpareil beads, and then coated with conventional release-retarding materials such as wax, enteric coating and the like. In an embodiment, beads can be formed, wherein any compound described herein is mixed with material to provide a mass (mass) from which the compound is leached. In an embodiment, beads can be engineered to provide different release rates using different materials etc. by changing the characteristic such as thickness, porosity of coating or mass. Beads with different release rates can be combined into single dosage form, to provide variable or continuous release. Beads can be contained in a capsule, or compressed into tablets.

[0137] In embodiments, the modified dosage form herein includes a delayed release dosage form with a delayed release profile. The delayed release dosage form can include a delayed release tablet or a delayed release capsule. The delayed release tablet is a solid dosage form that releases a compound (or more compounds) described herein after administration at a time different from that of immediate release. The delayed release capsule is a solid dosage form in which the drug is encapsulated in a hard or soft soluble container made of a suitable form of gelatin, and the solid dosage form releases a drug (or more drugs) after administration at a time different from that of immediate release. For example, enteric-coated tablets, capsules, granules, and beads are examples of delayed release dosage forms. Enteric-coated tablets, capsules, granules, and beads pass through the stomach and release the drug in the intestine. In embodiments, the delayed release tablet is a solid dosage form that is included in a conglomerate of pharmaceutical particles that releases a drug (or more drugs) at a time different from that of immediate release after administration. In embodiments, the conglomerate of pharmaceutical particles is covered with a coating that delays drug release. In an embodiment, the delayed-release capsule is a solid dosage form comprising an agglomerate of pharmaceutically acceptable particles that releases a drug (or more drugs) at a time different from immediate release after administration. In an embodiment, the agglomerate of pharmaceutically acceptable particles is coated with a coating that delays drug release.

[0138] Delayed release dosage forms are known to those skilled in the art. For example, coated delayed release beads or granules, wherein any compound described herein is applied to beads, such as confectioners nonpareil beads, and then coated with conventional release delaying materials such as wax, enteric coatings and the like. In an embodiment, beads can be formed in which any compound described herein is mixed with a material to provide a mass from which the drug is leached. In an embodiment, the beads can be engineered to provide different release rates by changing the properties of the coating or mass, such as thickness, porosity, using different materials, etc. In an embodiment, enteric coated granules of any compound described herein can be contained in enteric coated capsules or tablets that release the granules in the small intestine. In an embodiment, the granules have a coating that remains intact until the coated granules reach at least the ileum and thereafter provide delayed release of the drug in the colon. Suitable enteric coating materials are well known in the art, for example, Coatings such as methacrylic acid and methyl methacrylate polymers, among others. Granules can be contained in capsules, or compressed into tablets.

[0139] In an embodiment, any compound described herein is incorporated into a porous inert carrier that provides a delayed release profile. In an embodiment, the porous inert carrier includes a channel or passage from which the drug diffuses into the surrounding fluid. In an embodiment, any compound described herein is incorporated into an ion exchange resin to provide a delayed release profile. When the drug-resin complex contacts gastrointestinal fluid and the ionic components dissolved therein, the predetermined release rate of the drug from the resin can result in a delayed effect. In an embodiment, a membrane is used to control the rate of release from a reservoir containing the drug. In an embodiment, a liquid product can also be used to provide a delayed release profile. For example, a liquid product composed of solid particles dispersed throughout the liquid phase, the particles being insoluble in the liquid phase. The suspension is formulated to at least allow a reduction in the frequency of administration compared to the frequency of administration presented by the drug as a conventional dosage form (for example, as a solution or a conventional solid dosage form that immediately releases the drug). For example, a suspension of an ion exchange resin component or microbeads.

[0140] In embodiments, pharmaceutical compositions described herein are suitable for ophthalmic administration or parenteral administration, and parenteral administration includes, for example, intramuscular (im), intravenous (iv), subcutaneous (sc), intraperitoneal (ip) or intrathecal (it). Parenteral compositions or ophthalmic compositions must be sterile, for being used by injection, infusion, instillation or implantation into the body, and can be packaged in single-dose containers or multi-dose containers. In embodiments, liquid pharmaceutical compositions for ophthalmic administration or parenteral administration to experimenter include active substances, for example, any compound described herein is in any corresponding amount described above. In embodiments, pharmaceutical compositions for ophthalmic administration or parenteral administration are formulated into a cumulative volume of about, for example, 1ml, 2ml, 3ml, 4ml, 5ml, 7.5ml, 10ml, 20ml, 25ml, 50ml, 100ml, 200ml, 250ml or 500ml. In embodiments, compositions are contained in bags, glass bottles, plastic bottles or bottles.

[0141] In embodiments, the pharmaceutical composition for ophthalmic administration or parenteral administration includes the corresponding amount described above for any compound described herein. In embodiments, the pharmaceutical composition for ophthalmic administration or parenteral administration includes about 0.0001 mg to about 500 mg of any compound described herein. In embodiments, the pharmaceutical composition for ophthalmic administration or parenteral administration to a subject may include any compound described herein at a corresponding concentration of about 0.005 mg / ml to about 500 mg / ml. In embodiments, the pharmaceutical composition for ophthalmic administration or parenteral administration includes any compound described herein at a corresponding concentration of, for example, about 0.05 mg / ml to about 50 mg / ml, about 0.1 mg / ml to about 50 mg / ml, about 0.1 mg / ml to about 10 mg / ml, about 0.05 mg / ml to about 25 mg / ml, about 0.05 mg / ml to about 10 mg / ml, about 0.05 mg / ml to about 5 mg / ml, or about 0.05 mg / ml to about 1 mg / ml. In an embodiment, a pharmaceutical composition for ocular or parenteral administration comprises any compound described herein at a respective concentration of, for example, about 0.05 mg / ml to about 15 mg / ml, about 0.5 mg / ml to about 10 mg / ml, about 0.25 mg / ml to about 5 mg / ml, about 0.5 mg / ml to about 7 mg / ml, about 1 mg / ml to about 10 mg / ml, about 5 mg / ml to about 10 mg / ml, or about 5 mg / ml to about 15 mg / ml.

[0142] In embodiments, a pharmaceutical composition for ophthalmic administration or parenteral administration is provided, wherein the pharmaceutical composition continues to be stable for at least six months. In embodiments, a pharmaceutical composition for ophthalmic administration or parenteral administration presents a reduction in the active substance of no more than about 5% in, for example, 3 months or 6 months, such as (S)-3-amino-4-(difluoromethylene) cyclopent-1-ene-1-carboxylic acid or a pharmaceutically acceptable salt thereof. In embodiments, the amount of (S)-3-amino-4-(difluoromethylene) cyclopent-1-ene-1-carboxylic acid or a pharmaceutically acceptable salt thereof degrades to no more than about, for example, 2.5%, 1%, 0.5% or 0.1%. In embodiments, degradation is less than about, for example, 5%, 2.5%, 1%, 0.5%, 0.25%, 0.1% in at least six months.

[0143] In an embodiment, a pharmaceutical composition for ocular or parenteral administration is provided, wherein the pharmaceutical composition remains soluble. In an embodiment, a pharmaceutical composition for ocular or parenteral administration is provided, which is stable, soluble, topical compatible, and / or ready-to-use. In an embodiment, the pharmaceutical composition herein is ready-to-use for direct administration to a subject in need thereof.

[0144] The pharmaceutical compositions provided herein for ophthalmic or parenteral administration may comprise one or more excipients, such as solvents, solubility enhancers, suspending agents, buffers, isotonic agents, stabilizers, or antimicrobial preservatives. When used, the excipients of the ophthalmic or parenteral compositions will not adversely affect the stability, bioavailability, safety, and / or efficacy of any compound described herein used in the composition. Thus, ophthalmic or parenteral compositions are provided in which there is no incompatibility between any components of the dosage form.

[0145] In an embodiment, an ophthalmic or parenteral composition comprising any of the compounds described herein comprises a stabilizing amount of at least one excipient. For example, the excipient can be selected from the group consisting of a buffer, a solubilizer, a tonicity agent, an antioxidant, a chelating agent, an antimicrobial agent, and a preservative. It will be understood by those skilled in the art that an excipient can have more than one function and be classified into one or more defined groups.

[0146] In embodiments, ophthalmic compositions or parenteral compositions include any compound described herein and an excipient, wherein the excipient is present in a weight percentage (w / v) of less than about, for example, 10%, 5%, 2.5%, 1%, or 0.5%. In embodiments, the excipient is present in a weight percentage of about, for example, 1.0% to 10%, 10% to 25%, 15% to 35%, 0.5% to 5%, 0.001% to 1%, 0.01% to 1%, 0.1% to 1%, or 0.5% to 1%. In embodiments, the excipient is present in a weight percentage of about, for example, 0.001% to 1%, 0.01% to 1%, 1.0% to 5%, 10% to 15%, or 1% to 15%.

[0147] In an embodiment, an ophthalmic or parenteral composition of any compound described herein is provided, wherein the pH of the composition is between about 4.0 and about 8.0. In an embodiment, the pH of the composition is, for example, between about 5.0 and about 8.0, between about 6.0 and about 8.0, or between about 6.5 and about 8.0. In an embodiment, the pH of the composition is, for example, between about 6.5 and about 7.5, between about 7.0 and about 7.8, between about 7.2 and about 7.8, or between about 7.3 and about 7.6. In an embodiment, the pH of the aqueous solution is, for example, about 6.8, about 7.0, about 7.2, about 7.4, about 7.6, about 7.7, about 7.8, about 8.0, about 8.2, about 8.4, or about 8.6.

[0148] In an embodiment, a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid or a pharmaceutically acceptable salt thereof provides a C of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid having a C of less than about, for example, 2000 ng / ml, 1000 ng / ml, 850 ng / ml, 800 ng / ml, 750 ng / ml, 700 ng / ml, 650 ng / ml, 600 ng / ml, 550 ng / ml, 450 ng / ml, 400 ng / ml, 350 ng / ml, or 300 ng / ml. 最大 In embodiments, the pharmaceutical composition provides a C of less than about, for example, 250 ng / ml, 200 ng / ml, 150 ng / ml, or 100 ng / ml. 最大 in vivo plasma profile.

[0149] In an embodiment, provided herein are pharmaceutical compositions comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid or a pharmaceutically acceptable salt thereof and one or more of any of the compounds described herein, wherein the composition provides an AUC of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid of less than about 900 ng·hr / ml. 0-∞ Constant in vivo plasma profile.

[0150] In an embodiment, the pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid or a pharmaceutically acceptable salt thereof and one or more of any of the compounds described herein is 最大 Less than 3 hours. In an embodiment, the T 最大 Less than 2.5 hours. In an embodiment, the T 最大 Less than 2 hours. In an embodiment, the T 最大 Less than 1.5 hours. In an embodiment, the T最大 Less than 1 hour. In an embodiment, the T 最大 Less than 0.5 hours. In an embodiment, the T 最大 Less than 0.25 hours.

[0151] In embodiments, a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid, or a pharmaceutically acceptable salt thereof, and one or more compounds described herein provides at least about 80% dissolution within the first 20 minutes of administration to a subject in need thereof. In embodiments, a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid, or a pharmaceutically acceptable salt thereof, and one or more compounds described herein provides at least about, for example, 85%, 90%, or 95% dissolution within the first 20 minutes of administration to a subject in need thereof. In embodiments, a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid, or a pharmaceutically acceptable salt thereof, and one or more compounds described herein provides at least 80% dissolution within the first 10 minutes of administration to a subject in need thereof.

[0152] It should be understood that the corresponding amounts of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid or a pharmaceutically acceptable salt thereof and one or more of any compounds described herein are applicable to all dosage forms described herein, including conventional dosage forms, modified dosage forms, and ophthalmic formulations and parenteral formulations described herein. One skilled in the art will determine the appropriate amount based on criteria such as dosage form, route of administration, subject tolerance, efficacy, therapeutic goals, and therapeutic benefits, as well as other pharmaceutically acceptable criteria.

[0153] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0154] As used herein, the terms "about" or "approximately" mean within an acceptable error range for a particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, according to the practice in the art, "about" can mean within 3 or more standard deviations. Alternatively, "about" can mean a range of up to 20%, up to 10%, up to 5%, and / or up to 1% of a given value. Alternatively, particularly with respect to biological systems or processes, the term can mean within an order of magnitude of a value, preferably within 5-fold, and more preferably within 2-fold of a value.

[0155] "PK" refers to pharmacokinetic profile. 最大 T is defined as the highest estimated plasma drug concentration (ng / ml) during the experimental period. 最大 is defined as when C 最大 The time (min) when AUC is estimated. 0-∞ The total area under the plasma drug concentration-time curve (ng·hr / ml) from the time the drug is administered until it is eliminated. The area under the curve is determined by the clearance rate. Clearance is defined as the volume of blood or plasma that completely clears its drug content per unit time (ml / min).

[0156] "Pharmaceutically acceptable" refers to molecular entities and compositions that are "generally regarded as safe," e.g., they are physiologically tolerable and do not typically produce allergic or similar adverse reactions such as stomach upset and the like when administered to humans. In embodiments, the term refers to molecular entities and compositions that are approved by a regulatory agency of the Federal or state government as being on the GRAS list or similar list under sections 204(s) and 409 of the Federal Food, Drug and Cosmetic Act that have undergone premarket review and are approved by the FDA, the U.S. Pharmacopeia, or another generally recognized pharmacopoeia for use in animals, and more particularly, in humans.

[0157] "Effective amount" or "therapeutically effective amount" means a dosage sufficient to alleviate one or more symptoms of the disorder, disease or condition being treated.

[0158] "Co-administered with," "co-therapy," "in combination with," "combination of," "combined with," or "administered together with" may be used interchangeably and mean the administration of two or more agents in the course of therapy. The agents may be administered together at the same time or separately at spaced intervals. The agents may be administered in a single dosage form or in separate dosage forms.

[0159] A "patient in need thereof" includes an individual who has been diagnosed with a disease, condition, or disorder for which treatment with (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid or a pharmaceutically acceptable salt thereof is indicated. "Patient" and "subject" are used interchangeably herein. Example

[0160] The examples provided herein are included merely to supplement the disclosure herein and should not be considered limiting in any respect.

[0161] General approach

[0162] (1R,4S)-2-Azabicyclo[2.2.1]hept-5-en-3-one (2) was purchased from Acella Chembio, San Diego, CA 92121 or AK Scientific, Inc., Union City, CA 94587. 4-Methoxybenzyl chloride was purchased from AK Scientific, Inc., Union City, CA 94587. 2-(Difluoromethyl)sulfinyl)pyridine (20) was purchased from Enamine Chemicals, Monmouth Jct., NJ 08852, Sigma-Aldrich Corp, St Louis, MO or synthesized from diethyl bromodifluoromethylphosphonate and 2-mercaptopyridine. See, Zhou, Q.; Ruffoni, A.; Gianatassio, R.; Fujiwara, Y.; Sella, E.; Shabat, D.; Baran, P.S. Angew. Chem. Int. Ed. 2013, 52, 3949-3952. 1,3-Dibromo-5,5-dimethylhydantoin was purchased from Acros Organics division of Thermo Fisher Scientific, Waltham, MA 02451. TPAP was purchased from Combi Blocks, Inc. San Diego, CA 92126. Cerium ammonium nitrate was purchased from Alfa Aesar, Ward Hill, MA 01835. All other reagents were purchased from Sigma-Aldrich, Fisher Scientific or Acros Organics and used without further purification. Anhydrous solvents (THF, CHCl, DMF) were purified by passing through a column containing activated alumina and a supported copper redox catalyst before use. Yields refer to chromatographic and spectral ( 1 H-NMR) homogeneous material. Analytical thin layer chromatography (TLC) was performed using Merck silica gel F-254 pre-coated plates (0.25 mm thick) were used and the components were visualized by UV light (254 nm) and / or staining with cerium ammonium molybdate. Flash column chromatography was performed on a 100 nm column with a variety of Teledyne cartridges (4 g-80 g, 40 μm-63 μm, ) were performed on a Teledyne Combiflash Rf Plus automated flash purification system. Purification was performed with hexane and ethyl acetate unless otherwise stated. 1 H NMR and 13C NMR spectra were recorded on a Bruker Avance-III NMR spectrometer in CDCl3 or D2O at 500 MHz and 126 MHz, respectively. Chemical shifts are reported in ppm, with multiplicities indicated by the following: s = singlet, d = doublet, t = triplet, q = quartet, sep = septet, dd = doublet of doublets, dt = triplet of doublets, m = multiplet, br = broad resonance. Coupling constants are reported in Hz. High-resolution mass spectral data were obtained at the Integrated Molecular Structure Education and Research Center (IMSERC), Northwestern University, on an Agilent 6210 LC-TOF spectrometer with an Agilent G1312A HPLC pump and an Agilent G1367B autoinjector in positive ion mode using electrospray ionization. Analytical HPLC was performed by using a reverse phase Agilent Infinity 1260 HPLC with a Phenomenex Kintex C-18 column (50 x 2.1 mm, 2.6 μm) and detection by UV absorbance at 254 nm.

[0163] Example 1

[0164] Preparation of (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3)

[0165] Method A

[0166] 4-Methoxybenzyl alcohol (35.80 mL, 0.29 mol, 1.5 equivalents) was added dropwise to concentrated HCl (300 mL) and stirred for 1 h. Water was added and the liquid was extracted with ether (2×100 mL). The ether was dried over Na2SO4 and concentrated to a volume of approximately 50 mL. A 2L flask equipped with an addition funnel was added with (1R, 4S)-2-azabicyclo[2.2.1]hept-5-en-3-one (21.00 g, 0.19 mol), DMF (600 mL) and THF (600 mL), and the flask was cooled to 0°C. NaH (8.45 g, 0.21 mol, 1.1 equivalents, 60% dispersion in mineral oil) was added in batches. The flask was placed under N2 and stirred for 30 min. The Et2O / PMBCl solution was transferred to the addition funnel and added dropwise at 0°C. The reaction was stirred at room temperature for 6 h. After completion, THF was removed in vacuo, and ether and water were added. Any solids were filtered, and the layers were separated. The aqueous layer was extracted with ether (3 × 100 mL), and the organic layers were combined and washed with brine (2 × 200 mL). After drying over Na2SO4 and concentration, a yellow oil was obtained. The crude oil was purified by flash chromatography to produce 32.2 g (0.14 mol, 73% yield) of protected (1R, 4S)-2-azabicyclo[2.2.1]hept-5-ene-3-one (3). The spectrum matched those in the literature. See Qiu, J.; Silverman, RBJ Med. Chem. 2000, 43, 706-720.

[0167] Method B

[0168] A dry 2-liter 3-neck round-bottom flask equipped with an overhead stirrer / 4-nitro-2-thiazolyl-1,2-dextrose-1,4-dextrose-2,4-dextrose-1,4-dextrose-2,4-dextrose-3,4-dextrose-4,4-dextrose-5,4-dextrose-6,4-dextrose-7,4-dextrose-8,4-dextrose-9,4-dextrose-10,4-dextrose-11,4-dextrose-12,4-dextrose-13,4-dextrose-14,4-dextrose-15,4-dextrose-26,4-dextrose-3,4-dextrose-16,4-dextrose-3,4-dextrose-13,4-dextrose-27,4-dextrose-30,4-dextrose-14,4-dextrose-31,4-dextrose-15,4-dextrose-32,4-dextrose-13,4-dextrose-33,4-dextrose-14,4-dextrose-34,4-dextrose-15,4-dextrose-35,4-dextrose-36,4-dextrose-14,4-dextrose-37 After all the LiHMDS had been added, the reaction mixture was stirred for another hour and the 500 ml dropping funnel was then removed and replaced with a smaller 125 ml dropping funnel loaded with 4-methoxybenzyl chloride (37.2 g, 240.5 mmol, 1.05 eq). The halide was added dropwise to the reaction flask. When about 1 / 4 of the chloride had been added, tetrabutylammonium iodide powder (1.3 g, 3.44 mmol, 0.015 eq) was added in a single portion. When all the 4-methoxybenzyl chloride had been added, the flask was initially warmed to room temperature and then heated to 60° C. in a heating mantle. The progress of the benzylation reaction was tracked over time by HPLC and LCMS. After 2 days at 60° C., when the reaction had reached a conversion of ~85% to the lactam (-)(1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one (3), the reaction was worked up. The fine solid precipitate in the reaction solution was removed by filtration under vacuum through a 17 cm large Buchner funnel / filter paper. The residue was washed with THF (200 ml), and the original filtrate was also collected and the combined golden filtrate was concentrated (rotary evaporator / vacuum / in a 40° C. water bath). The remaining golden oil was dissolved in EtOAc (350 ml) and washed with water (250 ml). After phase separation, the aqueous layer was back-extracted with EtOAc (2×100 ml). The EtOAc layers were combined and dried over anhydrous Na 2 SO 4 powder, filtered and concentrated (rotary evaporator / vacuum / in a 40° C. water bath) to a golden liquid. The crude product was purified by chromatography on a Biotage using a 340 g silica column and an EtOAc-hexane gradient [15% (2 CV) 15%-75% (8 CV) 100% (3 CV)], with fractions collected in 25×150 mm tubes. Product containing fractions were combined and concentrated (rotavap / vacuum / water bath at 40°C) to a golden liquid which was pumped on the vacuum line for several hours.

[0169] Method C

[0170] NaH (40.3 g, 1.01 mol, 60% purity, 1.1 equivalents) and Bu4NI (16.9 g, 45.8 mmol, 0.05 equivalents) were added to THF (300 mL), and then a solution of (1R, 4S)-2-azabicyclo [2.2.1] hept-5-ene-3-one (100.0 g, 916.3 mmol, 1 equivalent) in DMF (900 mL) was added dropwise to the mixture at 0 ° C. The mixture was stirred for 0.5 h, and p-methoxybenzyl chloride (215.2 g, 1.37 mol, 186.5 mL, 1.50 equivalents) was added dropwise to the above mixture at 0 ° C. The mixture was stirred for 1 h at 25 ° C. TLC (petroleum ether: ethyl acetate = 1: 1, R f =0.20) shows that the reactant is completely consumed. The mixture is diluted with MTBE (2L), and water (3.5L) is added. Any solid is filtered, and the layer is separated. The aqueous layer is extracted with MTBE (800mL×2), and the organic layers are combined and washed with brine (1L×2). The combined organic layers are dried over anhydrous Na2SO4 and concentrated to give a residue as a yellow oil. The residue is purified by column chromatography on silica gel with petroleum ether: ethyl acetate (10: 1~1: 1) to give a yellow oil. Obtain crude (1R, 4S) -2- (4- methoxybenzyl) -2- azabicyclo [2.2.1] hept-5-ene-3-one (3) (89.5g, 390.3mmol, 42.6% yield) as a yellow oil, which is used in the next step without further purification.

[0171] Example 2

[0172] Preparation of (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4)

[0173] Method A

[0174] To a solution of (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) (10.00 g, 43.62 mmol) in AcOH (110.0 mL) was added 1,3-dibromo-5,5-dimethylhydantoin (7.48 g, 26.17 mmol, 0.6 equiv). The reaction was stirred for 6 h, and upon completion, water was added. The aqueous layer was extracted with diethyl ether (3 x 200 mL), and the organic layers were combined, washed with 1 M NaOH, dried over Na2SO4, and concentrated. Purification by flash chromatography yielded (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) (14.40 g, 39.25 mmol, 90% yield) as a thick oil. The spectrum matched those in the literature. See Qiu, J.; Silverman, RBJ Med. Chem. 2000, 43, 706-720.

[0175] Method B

[0176] (1R, 4R)-(-)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-ene-3-one (15.5g, 67.60mmol, 1 equivalent) was dissolved in glacial acetic acid (125ml) in a 250ml round-bottom flask with a stirring bar. At room temperature, 1,3-dibromo-5,5-dimethylhydantoin (9.7g, 33.43mmol, 0.5 equivalent) was added to the acidic solution in multiple batches over 10 minutes. A serum cap / nitrogen needle was placed in the neck of the flask, and the reaction mixture was stirred at room temperature overnight. Within 20 minutes, after adding all the dibromides, the initially turbid yellow solution turned a clear golden yellow. The progress of the reaction was monitored by HPLC and LCMS. After stirring overnight, the reaction solvent was removed (rotary evaporator / vacuum / water bath at 55° C.) to provide a dark golden liquid which was then dissolved in dichloromethane (200 ml). Water (100 ml) was added and the mixture was transferred to a 1 L Erlenmeyer flask. 10% sodium sulfite solution (75 ml) was added and stirred vigorously in a conical flask for 1 / 2 hour to destroy unreacted dibromohydantoin. More water (100 ml) was added and then 3 M sodium hydroxide was slowly added and rapidly swirled in the conical flask to reach pH=7 (pH paper) for the aqueous layer. The flask contents were transferred to a 1 L separatory funnel; the conical flask was rinsed with dichloromethane (100 ml) and the rinses were combined in the funnel. The dichloromethane layer from the phase separation was saved, and the aqueous layer was back-extracted with dichloromethane (2 x 100 ml) and combined with the initially saved extracts, washed with saturated NaHCO (250 ml), water (250 ml), and brine (250 ml). The organic phase was dried over anhydrous NaSO powder, filtered, and concentrated (rotary evaporator / vacuum / water bath at 40° C.) to a golden liquid. The crude product was purified by chromatography on a Biotage using a 340 g silica column and an EtOAc-hexane gradient [15% (1 CV) 15%-75% (7.5 CV) 100% (3 CV)], with fractions collected in 25 x 150 mm tubes. The product containing fractions were combined and concentrated (rotavap / vacuum / water bath at 40°C) to give a golden liquid which was further pumped on the vacuum line for several hours to yield purified (lR,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]-hept-6-yl acetate (4) (23 g; 82%).

[0177] Example 3

[0178] Preparation of (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5)

[0179] Method A

[0180] (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) (12.8 g, 34.7 mmol) was dissolved in MeOH (270 mL) and KCO (14.40 g, 104.28 mmol, 3.0 equiv) was added. The reaction was stirred for 1 h, filtered and then concentrated. Ethyl acetate and water were added and the layers were separated. The organic layer was dried over NaSO and concentrated to give an off-white solid ((1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one) (25) which was used directly in the next step.

[0181] The compound was placed in a 500 mL flask and purged with argon. Dichloromethane (170 mL) was added, followed by Molecular sieves (10 g). TPAP (122.2 mg, 0.35 mmol, 0.01 equivalent) and NMO (8.14 g, 69.52 mmol, 2.0 equivalents) were then added, and the reaction mixture was stirred overnight. The reaction mixture was then filtered and concentrated to a volume of 20 mL and loaded directly onto a flash chromatography column. The resulting yellow solid can be recrystallized from hexane / ethyl acetate to obtain a white powder (1R, 4R, 7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) (5.96 g, 18.38 mmol, 52% yield). The spectrum matches those in the literature. See Qiu, J.; Silverman, RBJ Med. Chem. 2000, 43, 706-720.

[0182] Method B

[0183] (1R, 4R, 6S, 7R) -7- bromo- 2- (4- methoxybenzyl) -3- oxo -2- azabicyclo [2.2.1] hept- 6-yl acetate (4) (25.5 g, 69.2 mmol) was dissolved in MeOH (300 mL) and KCO (30 g, 0.23 mol, 3 equivalents) was added. The reaction was stirred for 1 h, filtered and then concentrated. Ethyl acetate and water were added and the layers separated. The organic layer was dried over NaSO and concentrated to produce an off-white solid ((1R, 4R, 6S, 7R) -7- bromo- 6- hydroxy -2- (4- methoxybenzyl) -2- azabicyclo [2.2.1] hept- 3- ketone), which was used directly in the next step. A three-necked flask was equipped with a vent line to a bubbler, a dropping funnel with a nitrogen inlet, and a septum. Add dichloromethane (160mL), and purge flask with nitrogen.Add oxalyl chloride (8.40mL, 98.0mmol, 1.4 equivalents), and the reaction is cooled to-78 ℃.DMSO (11.60mL, 0.16mol, 2.3 equivalents) is added to the charging funnel, and then slowly dropwise added with the speed of controlling violent gas precipitation (evolution).After adding, the reaction is stirred at-78 ℃ for 10min. The deacylated material is dissolved in dichloromethane (160mL), and slowly added to the reaction via the charging funnel. The reaction is stirred at-78 ℃ for 10min. Then triethylamine (68.3mL, 0.49mol, 7 equivalents) is added dropwise via the charging funnel. After completing, the reaction is stirred at-78 ℃ for 10min, is heated to room temperature, and is quenched with 1M HCl. After separation, the organic layer is through Na2SO4 drying, and concentrated in a fume hood. Purification via flash chromatography yielded (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) (13.5 g, 41.7 mmol, 60% yield) as a beige solid.

[0184] Method C

[0185] To (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) (96.5 g, 262.0 mmol, 1 eq) in MeOH (680 mL) was added K2CO3 (108.6 g, 786.2 mmol, 3 eq). The mixture was stirred at 25°C for 1 h. TLC (petroleum ether:ethyl acetate = 1:1, R f=0.65) show that the reaction is complete.Mixture is filtered and filtrate is concentrated under reduced pressure, to provide black brown solid.MTBE (500mL) is added to brown solid, and mixture is stirred for 3h, then filtered to provide filtrate, filtrate is concentrated under reduced pressure to provide crude product.Obtain crude compound (76.5g, 234.5mmol, 89.5% yield) as off-white solid, it is used to next step when it is not further purified.

[0186] The above crude compound (76.5 g, 234.5 mmol, 1 eq) was added to MeCN (400 mL). IBX (65.6 g, 234.5 mmol, 1.0 eq) was added to the above mixture in one portion at 20-30 ° C for 0.5 h. The reaction mixture was stirred at 75-80 ° C for 2 h. After this time, TLC (petroleum ether: ethyl acetate = 3: 1, R f =0.23) showed that the reaction was complete. The mixture was concentrated under reduced pressure to give a crude product, which was purified by column chromatography on silica gel with petroleum ether:ethyl acetate (20:1 to 1:1) to give (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) (48.5 g, 149.6 mmol, 63.7% yield) as an off-white solid.

[0187] Example 3(a)

[0188] Preparation of (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25)

[0189] (1R,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo-[2.2.1]-hept-6-yl acetate (4) (22.25 g, 60.42 mmol, 1 eq) was dissolved in a solvent mixture of methanol (120 ml) and water (15 ml) in a 500 mL round-bottom flask. Potassium carbonate powder (12.5 g, 90.45 mmol, 1.5 eq) was added to the golden solution, and the resulting turbid reaction mixture was sealed with a serum cap / N2 needle and stirred at room temperature overnight. The progress of the reaction was monitored by LCMS and HPLC. The reaction was worked up by evaporation of the volatiles (rotary evaporator / vacuum / water bath at 40°C). Distilled water (200 ml) was added to the dark golden oil obtained from the evaporation. The pH of the aqueous layer was adjusted to pH=7 with 1M hydrochloric acid, and the product was extracted into dichloromethane (200 ml, then 2×150 ml). The dichloromethane extracts were combined and washed with water (200 ml), brine (250 ml), and dried over Na 2 SO 4 powder. The dried extracts were filtered, and the spent drying agent was rinsed with dichloromethane (2×50 ml), and the combined extracts were concentrated (rotary evaporator / vacuum / water bath at 40° C.) to a golden oil. The golden product was divided into two approximately equal portions, and each portion was purified by chromatography on a Biotage on a 100 g silica column using an EtOAc-hexane gradient [20% (1 CV) 20%-100% (7 CV) 100% (5 CV)], with fractions collected in 25×150 mm tubes. The product fractions are merged and concentrated (rotary evaporator / vacuum / being in 40 ℃ water bath) into golden yellow liquid, and this golden yellow liquid is pumped on vacuum line for several hours.Two chromatographically purified samples (20g) are merged and crystallized from hexane-EtOAc.Collect the first batch of crystals (17g).The mother liquor is concentrated and crystallized from hexane-EtOAc, to provide the second batch of crystals (2g).Obtain (1R, 4R, 6S, 7R)-(+)-7-bromo-6-hydroxyl-2-(4-methoxybenzyl)-2-aza-bicyclo [2.2.1] heptan-3-one (25) (total 15g; 75%) as white crystalline powder.

[0190] Example 3(b)

[0191] Preparation of (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) by Swern oxidation

[0192] A 1 L, 3-necked round bottom flask equipped with an overhead stirrer, a 50 ml dropping funnel, and a serum cap / thermocouple / N2 needle was charged with a solution of oxalyl chloride (3.4 g (2.3 ml), 1.25 eq) and dichloromethane (90 ml), and the stirred acid chloride solution was cooled to -60° C. in an acetone / CO2 cooling bath. The dropping funnel was charged with a solution of DMSO (2.6 g (2.35 ml), 1.5 eq) in dichloromethane (18 ml), which was added to the cold acid chloride solution over 3 minutes. The resulting mixture was stirred at -60 ° C for 7 minutes, and then (1R, 4R, 6S, 7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]-heptan-3-one (25) (7.2 g, 22.1 mmol, 1 equivalent) was added to the solution over a period of 10 minutes. The reaction mixture was maintained at -60 ° C for 25 minutes, and then pure trimethylamine (21.5 ml, 7 equivalents) was placed in a dropping funnel and added to the flask. The resulting milky white solution was kept cold for 1 hour, the reaction was checked by HPLC / LCMS, and then the reaction was allowed to warm to room temperature within 2.5 hours before processing. Saturated brine (125 ml) was added to the flask, and ether (125 ml) was then added during processing. The quenched reaction was transferred to a 1 L separatory funnel. The upper layer was preserved and the aqueous layer below was extracted with ether (2×125 ml). The ether extracts were combined with the original extracts and then washed with 1M hydrochloric acid (125 ml), brine (125 ml) and water (50 ml). The organic phase was dried over anhydrous Na2SO4 powder, filtered, and the filter cake was washed with dichloromethane (2 x 50 ml), and the washings were combined with the filtrate. Volatiles were removed (rotary evaporator / vacuum / water bath at 40°C) to obtain a yellow liquid that solidified after standing. The solid was crystallized from EtOAc-hexane to obtain the first batch (5.31 g). The mother liquor was concentrated and crystallized to give the second batch (1.36 g). The mother liquor from the second crystallization was purified on a 25 g silica column eluted with an EtOAc-hexane gradient [20% (2 CV), 20%-100% (8 CV), 100% (2 CV)] on a Biotage, and the fractions were collected in 16 x 150 mm tubes. Chromatography yielded 250 mg of product. The combined yield of (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) was 6.8 g (94% yield).

[0193] Example 3(c)

[0194] Preparation of (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) by TPAP oxidation

[0195] A 2-liter 3-neck round-bottom flask equipped with an overhead stirrer and a serum cap / thermocouple / N2 needle was loaded with (1R, 4R, 6S, 7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]-heptane-3-one (25) (12g, 36.8mmol, 1 equivalent), 4-morpholine-N-oxide (12.9g, 110mmol, 3 equivalents) and 4A molecular sieve powder in dichloromethane (400ml). A catalytic amount of TPAP (25mg, 0.07mmol, 0.002 equivalent) was then added. The solution was stirred at room temperature under nitrogen as a green solution that darkened over time. The reaction was monitored every day by LC-MS. On the 2nd day, the reaction stagnated and a filter flask and a vacuum source were used to obtain a column ... In 40 ℃ of filtration reaction, add 4-morpholine-N-oxide (5.5g), 4A molecular sieve powder (10g) and TPAP (25mg).Reaction stagnates later in the 3rd day, and filtration reaction also restarts with fresh NMO (5.5g), 4A sieve (10g) and TPAP (25mg).At the end of the 4th day, remaining~7% bromohydrin, and therefore TPAP oxidation reaction is processed.Use Buchner flask and vacuum source, by filtering with the plastic sintering funnel that is filled with 1 / 2-cm sand, 1 / 2-cm anhydrous Na SO powder and 1-cm thick diatomaceous earth, remove the solid in the reaction solution.Filter cake is washed with methylene chloride (2 × 100ml and 50ml), until filtrate stream is colorless.Filtrate is concentrated into dark golden oil (rotary evaporator / vacuum / be in 40 ℃ water-bath), it demonstrates the sign of solidification on glass surface. The crude product was split in half and each half was chromatographed on silica gel (100 g) on ​​a Biotage eluting with an EtOAc-hexane gradient of 20% (1 CV), 20%-100% (7.5 CV) and 100% (4 CV) collecting fractions in 25 x 150 mm tubes. The product fractions from both chromatography steps were combined and concentrated (rotary evaporator / vacuum / water bath at 40° C.) to afford a white powder.

[0196] The powder was crystallized from EtOAc-hexane to obtain the first batch of crystals (8.5 g). The mother liquor was concentrated and crystallized to give the second batch (1.5 g). The combined yield of (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) was 10 g (80%).

[0197] Example 4

[0198] Preparation of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6)

[0199] Method A

[0200] (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) (1.00 g, 3.09 mmol) and 2-((difluoromethyl)sulfinyl)pyridine (20) (715.10 mg, 3.70 mmol, 1.2 equiv) were added to a round bottom flask and purged with argon. DMF (15 mL) was added and the reaction was cooled to between -55°C and -65°C. KO was added via a syringe pump over 1 h. t To the product of 4-nitro-1-oxo-2-nitro-4-oxo-6-nitro-1-oxo ... =-46.64(c0.80,CHCl3); mp85-87℃; 1 H NMR (500 MHz, CDCl3) δ 7.14 (d, J = 8.4 Hz, 1H), 6.86 (d, J = 8.5 Hz, 1H), 4.60 (d, J = 14.6 Hz, 1H), 4.19 (s, 0H), 4.14 (s, 0H), 3.90 (d, J = 14.7 Hz, 1H), 3.79 (s, 1H), 3.00 (s, 0H), 2.83 (dq, J = 14.6, 3.0 Hz, 1H), 2.27 (d, J = 15.2 Hz, 1H). Figure 1 . 13CNMR (126 MHz, CDCl3) δ 173.0, 159.5, 153.9 (dd, J = 287.5, 283.8 Hz), 129.7, 127.5, 114.3, 87.1 (dd, J = 24.9, 23.5 Hz), 63.4, 63.3, 55.3, 50.8 (d, J = 17.1 Hz), 44.6, 24.8. Figure 2 . 19 F NMR (376 MHz, CDCl3) δ -88.15 (dp, J = 55.1, 2.7 Hz), -88.88 (dq, J = 54.8, 2.8 Hz). Figure 3 IR(film,cm -1 )3013,1785,1683,1551; for C 15 H 14 BrF2NO2+Na + HMRS(ESI + )The calculated value is: 380.0074; the measured value is 380.0075.

[0201] Method B

[0202] 2-(Difluoromethylsulfonyl)pyridine (20) (2.5 g, 12.94 mmol, 1.2 eq) and (1R,4R,7R)-(+)-7-bromo-2-(4-methoxy-benzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) (3.5 g, 10.8 mmol, 1 eq) were combined in a round bottom flask with a stirring bar and dimethylformamide (32 ml) was added. The resulting yellow solution was sealed with a serum cap / N2 needle / thermocouple and cooled to -40°C. Potassium bis(trimethylsilyl)amide (KHMDS) solution (15.1 ml, 15.1 mmol, 1.4 eq) was added and the temperature was maintained between -40°C and -35°C. As the base was added, the reaction solution turned dark orange. The resulting reaction mixture was stirred at -40°C for 1 hour and then allowed to gradually warm to room temperature. The reaction was quenched with saturated NH4Cl solution (10ml), stirred for 10 minutes, 3M hydrochloric acid (40ml) was added, stirred for 10 minutes, and then the flask contents were heated at 60 ℃ in a heating bath for 1.5 hours, and then cooled to room temperature. Water (35ml) was added, and the reaction was extracted with tert-butyl methyl ether (MTBE) (3 × 75ml). The ether extracts were combined into a portion, and washed with salt water, dried over anhydrous Na2SO4, and filtered through a Chem-R-Us plastic sintered funnel to remove the used desiccant. The filtrate was concentrated (rotary evaporator / vacuum / in a 40 ℃ water bath) to obtain a light brown oil. The crude product was purified by chromatography on a 100g silica column by EtOAc-hexane gradient [15% (1CV) 15%-75% (7.5CV) 100% (3CV)] on Biotage, and the fractions were collected in a 16 × 100mm tube. Product fractions were combined and concentrated (rotavap / vacuum / water bath at 40°C) to a golden liquid that was pumped on the vacuum line for several hours to yield (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) (2.5 g; 63%).

[0203] Method C

[0204] To a solution of (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) (48.5 g, 149.6 mmol, 1 eq) and 2-((difluoromethyl)sulfinyl)pyridine (20) (31.8 g, 164.6 mmol, 1.1 eq) in DMF (800 mL) was added a solution of t-BuOK (30.2 g, 269.3 mmol, 1.8 eq) in DMF (800 mL) very slowly dropwise at -57 to -52°C. The reaction was stirred at -55°C for 0.5 h and then saturated NH4Cl solution (400 mL) was slowly added dropwise to the reaction mixture at a temperature below -30°C. After the addition, 6N HCl solution (360 mL) was added to the above mixture at a temperature below -20°C. The mixture was heated to 10°C and stirred at 65°C for 1 h. TLC (petroleum ether:ethyl acetate=3:1, R f =0.50) showed a new spot. The mixture was added to water (4 L) and extracted with MTBE (2 L x 2). The organic layer was separated and washed with brine (2 L), then dried over Na2SO4 and concentrated under reduced pressure to give a residue as a red oil. The crude product was purified by column chromatography on silica gel with petroleum ether: ethyl acetate (20: 1 to 1: 1) to give (1R, 4R, 7R) -7- bromo-6- (difluoromethylene) -2- (4-methoxybenzyl) -2- azabicyclo [2.2.1] heptan-3-one (6) (32.5 g, 90.7 mmol, 60.6% yield) as a white solid.

[0205] Example 5

[0206] Preparation of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7)

[0207] Method A

[0208] (1R, 4R, 7R) -7- bromo-6- (difluoromethylene) -2- (4-methoxybenzyl) -2- azabicyclo [2.2.1] heptane -3- one (6) (140 mg, 0.39 mmol) was added to MeCN (2.0 mL) and cooled to 0 ° C. Cerium ammonium nitrate (643.5 mg, 1.17 mmol, 3 equivalents) in H o (0.75 mL) was added dropwise. The reaction was allowed to warm to room temperature and stirred for 1 h. After completion, water was added and the solution was extracted with ethyl acetate (2 × 15 mL). The organic layer was dried over Na sO and concentrated under reduced pressure. Flash chromatography produced (1R, 4R, 7R) -7- bromo-6- (difluoromethylene) -2- azabicyclo [2.2.1] heptane -3- one (7) (75 mg, 0.315 mmol, 80% yield) as a white solid. =+38.5(c0.90,CHCl3); mp139-141℃; 1 H NMR (500 MHz, CDCl3) δ 5.87 (s, 1H), 4.41 (s, 1H), 4.32 (s, 1H), 2.96 (s, 1H), 2.87 (dq, J = 15.4, 3.4 Hz, 1H), 2.32 (d, J = 15.2 Hz, 1H). Figure 4 . 13 C NMR (126 MHz, CDCl3) δ 174.9, 153.5 (t, J = 287.5 Hz), 88.7 (t, J = 24.1 Hz), 60.6, 51.5, 50.3, 24.3. Figure 5 . 19 F NMR (376 MHz, CDCl3) δ -88.60 (dq, J = 55.1, 2.8 Hz), -88.88 (dp, J = 54.6, 2.5 Hz). Figure 6 IR (film, cm-1) 3249.1788, 1678, 1397; for C7H6BrF2NO+H + The HMRS (ESI+) calculated value is: 237.9679; the found value is 237.9678.

[0209] Method B

[0210] Ten minutes before the oxidative cleavage reaction, an aqueous solution of cerium (IV) ammonium nitrate (CAN) (6.4 g, 11.67 mmol, 2.94 equivalents) in 20 ml of distilled water was prepared. (1R, 4R, 7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]heptan-3-one (1.4 g, 3.91 mmol, 1 equivalent) was dissolved in acetonitrile (70 ml) and stirred with a stirring bar in a round-bottom flask. The CAN aqueous solution was added dropwise to the flask, and the resulting mixture was stirred at room temperature for several hours, with the progress of the reaction monitored by HPLC and LCMS. The reaction was processed by pouring the reaction into a 500 ml separatory funnel, and then EtOAc (300 ml) was added, shaken, and the upper layer was saved. The lower aqueous layer was extracted with more EtOAc (2×50 mL). The ethyl acetate extracts were combined into one portion and washed with water (4 x 10 ml) and saturated brine (25 ml), then dried over anhydrous Na2SO4. After filtering through a plastic sintered funnel to remove the spent drying agent, the filtrate was concentrated (rotary evaporator / vacuum / in a 40°C water bath) to obtain a light brown oil. The crude product was purified by chromatography on a 25 g silica column on a Biotage using an EtOAc-hexane gradient [15% (1 CV) 15%-75% (7.5 CV) 100% (3 CV)] and fractions were collected in 16 x 100 mm tubes. Product-containing fractions were combined and concentrated (rotavap / vacuum / water bath at 40°C) to a golden liquid that was pumped on the vacuum line for several hours to yield purified (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) (0.65 g; 70%).

[0211] Example 6

[0212] Preparation of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) and (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9)

[0213] Method A

[0214] (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) (890.0 mg, 3.74 mmol) was added to dichloromethane (18.0 mL), followed by Boc2O (978.8 mg, 4.49 mmol, 1.2 eq), DMAP (45.7 mg, 0.37 mmol, 0.1 eq) and Et3N (0.78 mL, 5.61 mmol, 1.5 eq). The reaction was stirred for 1 h and then washed with 1 M HCl (10 mL), dried over Na2SO4 and concentrated. The resulting oil containing (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) was dissolved in methanol (18.0 mL) and KCO (1.55 g, 11.21 mmol, 3.0 equiv) was added and the reaction stirred for 6 h. After completion, as indicated by LC / MS (methanolysis of the lactam occurred within the first 10 min), the reaction was diluted with brine and extracted with ethyl acetate (3 x 200 mL). After drying over NaSO, concentration, and purification by flash chromatography, (S)-methyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) (570 mg, 1.97 mmol, 52% yield) was obtained as a white solid. =+104.8(c0.50,CHCl3); mp95-97℃; 1 H NMR (500 MHz, CDCl3) δ 6.58 (s, 1H), 5.50 (d, J = 9.1 Hz, 1H), 4.63 (d, J = 8.7 Hz, 1H), 3.75 (s, 3H), 3.33 (d, J = 20.4 Hz, 1H), 3.21 (dd, J = 20.3, 2.7 Hz, 1H), 1.42 (s, 9H). Figure 7 . 13 C NMR (126 MHz, CDCl3) δ 164.3, 154.7, 154.6, 152.4 (t, J = 288.5 Hz), 150.1, 140.6, 135.5, 88.9 (dd, J = 21.8, 20.2 Hz), 80.1, 55.3, 51.9, 31.1, 28.3. Figure 8 . 19 F NMR (376 MHz, CDCl3) δ -84.49 (d, J = 43.6 Hz), -85.91 (d, J = 43.4 Hz). Figure 9 IR(film,cm -1 )3347,2987,1773,1681; for C13 H 17 F2NO4+Na + HMRS(ESI + )The calculated value is: 312.1023; the measured value is 312.1018.

[0215] Method B

[0216] To a solution of (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) (14.4 g, 60.5 mmol, 1 eq) in DCM (150 mL) was added DMAP (739.0 mg, 6.05 mmol, 0.1 eq) and TEA (9.18 g, 90.7 mmol, 12.6 mL, 1.5 eq). (Boc)2O (15.8 g, 72.6 mmol, 16.6 mL, 1.2 eq) was then slowly added. After the addition, the mixture was stirred at 25 ° C for 1 h. TLC (petroleum ether: ethyl acetate = 1: 1, R f =0.20) shows that the reaction is complete. The mixture is adjusted to pH=3-4 with 1N HCl solution, then the organic layer is separated and washed with brine (100 mL), dried over Na2SO4, and concentrated under reduced pressure to give (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) (7.50 g, crude) as a dark brown solid, which is used in the next step without further purification. (1R, 4R, 7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) (7.50 g, 22.1 mmol, 1 eq) is dissolved in MeOH (55 mL), followed by the addition of CH3ONa (1.44 g, 26.6 mmol, 1.2 eq). The mixture was stirred at 0°C for 1 h. TLC (petroleum ether:ethyl acetate=1:1, R f =0.70) show that the reaction is complete.Water (100mL) is added to reaction mixture, and mixture is extracted with MTBE (200mL×2), washed with salt solution (150mL), use Na SO Drying, filter, and under reduced pressure concentrate, to provide the residue (rough thing) as red solid. The crude product is used petroleum ether by column chromatography on silica gel: ethyl acetate (20: 1~1: 1) purifying, to provide (S)-3-((tert-butoxycarbonyl) amino)-4-(difluoromethylene) cyclopent-1-alkene-1-methyl-formiate (9) (5.20g, 17.9mmol, 81.0% yield) as white solid.

[0217] Example 7

[0218] Preparation of tert-butyl (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-3-oxo-2-azabicyclo[2.2.1]heptane-2-carboxylate (8)

[0219] The methylene chloride (30ml) used in this reaction was deoxidized with gas dispersion tube and nitrogen before being used for reaction.(1R, 4R, 7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo [2.2.1]-heptane-3-ketone (7) (1.4g, 5.88mmol, 1 equivalent) and tert-butyl dicarbonate (2.56g, 11.73mmol, 2 equivalents) were dissolved in the methylene chloride (30ml) in a 100ml round-bottomed flask.4-(dimethylamino)-pyridine (DMAP) (0.3g, 2.46mmol, 7.3 equivalents) was dissolved in triethylamine (6ml, 43mmol, 0.4 equivalent), and then amine was dropwise added to the reaction under a nitrogen blanket. The resulting reaction mixture in the flask was sealed with serum cap / N2 needle, and content was continued at room temperature for 1 hour. The product of 4-nitro-2-oxo-2-propanediol (5-nitro-1-propanediol) and 4-nitro-1-propanediol (5-nitro-1-propanediol) is dissolved in 1% 4-nitro-1-propanediol (5-nitro-1-propanediol) and 4-nitro-1-propanediol (5-nitro-1-propanediol) and 4-nitro-1-propanediol (5-nitro-1-propanediol) is added in ... Product containing fractions were combined and concentrated (rotavap / vacuum / water bath at 40°C) to a golden liquid that was pumped on the vacuum line for several hours to yield purified tert-butyl (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-3-oxo-2-azabicyclo[2.2.1]heptane-2-carboxylate (1.65 g; 82%).

[0220] Example 8

[0221] Preparation of (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19)

[0222] By the solvent methanol-water (3:1v / v) used in this reaction before being about to be used for reaction with gas dispersion tube and nitrogen deoxidation.By (1R, 4R, 7R)-(+)-7-bromo-6-(difluoromethylene)-3-oxo-2-azabicyclo [2.2.1]-heptyl-2-t-butyl formate (8) (1.6g, 4.73mmol, 1 equivalent) be dissolved in methanol aqueous solution (35ml), and under nitrogen atmosphere, stir with stirring rod, and potassium carbonate powder (1.96g, 14.18mmol, 3 equivalents) is joined in solution with single portion.Reaction flask is sealed with serum cap and nitrogen needle, and internal mixture stirring is continued 12 hours.Add dichloromethane (50ml), and then with 1M hydrochloric acid acidifying of two-phase crude reaction mixture, to destroy excessive potassium carbonate and make pH reach 7 (pH paper).To be separated, and then from dichloromethane layer, remove volatile matter. The crude product was purified by chromatography on a 25 g silica column on a Biotage by a methanol-CHCl gradient [1% (1 CV) 1% to 20% (7.5 CV) 20% (3 CV)] and fractions were collected in 16 x 100 mm tubes. Product-containing fractions were combined and concentrated (rotavap / vacuum / water bath at 40° C.) to a golden solid that was pumped on the vacuum line for several hours to yield purified (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) (0.733 g, 56%).

[0223] Example 9

[0224] Preparation of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid hydrochloride (1)

[0225] Method A

[0226] (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9) (570.0 mg, 1.97 mmol) was dissolved in dioxane (1.00 mL) and 6M HCl (9 mL) was added. After heating at 80° C. for 2 h, the reaction was concentrated to produce (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid hydrochloride (1) (403.0 mg, 1.90 mmol, 97% yield) as a light brown powder. Crystallization from ethanol / diethyl ether improved the purity to >99%. =+67.2(c0.90,H2O); mp207℃(decomposition); 1H NMR (500 MHz, D2O) δ 6.59 (s, 1H), 4.70 (s, 13H), 3.39 (d, J = 20.5 Hz, 1H), 3.33 (d, J = 20.8 Hz, 1H). Figure 10 . 13 C NMR (126 MHz, D2O) δ 167.2, 153.0 (dd, J = 290.1, 288.4 Hz), 141.8, 134.3, 86.1 (dd, J = 26.6, 21.2 Hz), 54.8 (d, J = 5.7 Hz), 31.1. Figure 11 . 19 F NMR (470 MHz, D2O) δ -83.1 (dq, J = 40.8, 2.8 Hz), -83.5 (dq, J = 40.4, 2.1 Hz). Figure 12 IR(film,cm -1 )3348,3075,2981,2883,2829,2600,2434,1771,1686; for HMRS (ESI - )The calculated value is: 174.0372; the measured value is 174.0369.

[0227] Method B

[0228] (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) (5.20 g, 17.9 mmol, 1 equivalent) was added to 4M HCl(g) / EtOAc (100 mL), and the mixture was stirred at 20° C.-30° C. for 2 h. TLC (petroleum ether:ethyl acetate=5:1, R f =0) indicates that starting material is completely consumed.Mixture is concentrated under reduced pressure to provide (S)-3-amino-4-(difluoromethylene) cyclopent-1-ene-1-methyl formate hydrochloride (3.00g, crude material, HCl salt) as yellow solid, it is used to next step when not further purified.Above compound (3.00g, 13.3mmol, 1.0 equivalent) is added to MeOH (15mL), and at 20 ℃-30 ℃ by LiOH × H o (1.39g, 33.2mmol, 2.5 equivalent) in H solution of o (10mL) is slowly added to above mixture.This mixture is stirred at 20 ℃-30 ℃ and continues 3h.TLC (dichloromethane: methanol=5:1, R f=0.40) indicated that the starting material was completely consumed. The mixture was adjusted to pH = 2-3 with 6M HCl solution and concentrated to give a crude product, which was purified by reverse phase HPLC (Agela C18 330 g; mobile phase: [water (0.1% HCl)-MeOH]; B%: 10%-20%, 20 min, 70 mL / min) to give (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid hydrochloride (1) (1.80 g, 8.46 mmol, 63.7% yield, 99.5% purity) as a white solid.

[0229] Example 10

[0230] Preparation of (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid hydrochloride (1)

[0231] 6M hydrochloric acid is prepared by mixing concentrated hydrochloric acid (10ml) and water (10ml).The THF used in this reaction is deoxidized with gas dispersion tube and nitrogen before being used for reaction.(S)-3-((tert-butoxycarbonyl) amino)-4-(difluoromethylene)-cyclopent-1-ene-1-carboxylic acid (19) is dissolved in THF (2ml) and stirred in the 10ml round-bottom flask with stirring bar.6M hydrochloric acid (2ml) is added.Reaction mixture is stirred at room temperature for 2 hours, and then THF and water are removed overnight with active nitrogen gas stream.Pumping of pink solid residue on vacuum line is continued for several hours, to remove any residual solvent, produce (S)-3-amino-4-(difluoromethylene)-1-cyclopentene-1-carboxylic acid hydrochloride (1) (~100mg as pink solid; 86%).

[0232] It should be understood that the examples and embodiments provided herein are exemplary examples and embodiments. Those skilled in the art will envision various modifications of the examples and embodiments consistent with the scope of the disclosure herein. Such modifications are intended to be covered by the claims.

[0233] The present invention also relates to the following items:

[0234] 1. A process for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a salt thereof, comprising:

[0235] Converting (1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one (2) to (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4);

[0236] Converting (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) to (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5);

[0237] Converting (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5) to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6);

[0238] Converting (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7);

[0239] Converting (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) to (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8);

[0240] converting (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) to (S)-methyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9); and

[0241] Methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) is converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1), optionally followed by acidification to provide its hydrochloride salt.

[0242] 2. A process according to claim 1, wherein (1R, 4S)-2-azabicyclo[2.2.1]hept-5-en-3-one (2) is converted into (1R, 4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3); and (1R, 4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) is converted into (1R, 4R, 6S, 7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4).

[0243] 3. A process according to claim 1, wherein (1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one (2) is reacted with a. PMBOH, HCl, NaH, THF / DMF; and b. DBDMH, AcOH to produce (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4).

[0244] 4. A process according to claim 1, wherein (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) is reacted with a. K2CO3, an alcohol; and b. 2-iodoacylbenzoic acid (IBX), MeCN to produce (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5).

[0245] 5. A process according to claim 1, wherein (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) is reacted with a. K2CO3, an alcohol; and b. TPAP, NMO to produce (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5).

[0246] 6. The process according to item 1, wherein (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) is reacted with 2-((difluoromethyl)sulfinyl)pyridine (20), KO t Bu, DMF, NH4Cl, and HCl react to produce (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6).

[0247] 7. A process according to claim 1, wherein (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5) is reacted with tert-butyllithium and F2CHP(O)(OEt)2 to produce (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6).

[0248] 8. A process according to claim 1, wherein (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) is reacted with CAN, MeCN, and H2O to produce (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7).

[0249] 9. A process according to claim 1, wherein (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) is reacted with Boc2O, DMAP, Et3N, and CH2Cl2 to produce (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8).

[0250] 10. A process according to claim 1, wherein (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) is reacted with K2CO3, methanol or ethanol to produce (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester or (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid ethyl ester.

[0251] 11. A process according to claim 1, wherein (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) is reacted with K2CO3, methanol, and CH3ONa to produce (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9).

[0252] 12. A process according to claim 10, wherein methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate or ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate is reacted with HCl to produce (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof.

[0253] 13. (S)-3-Amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof prepared by the process according to item 1.

[0254] 14. A process for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a salt thereof, comprising:

[0255] Converting (1R,4S)-(-)-2-azabicyclo[2.2.1]hept-5-en-3-one (2) to (1R,4S)-(-)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3);

[0256] Converting (1R,4S)-(-)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) to (1R,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4);

[0257] Converting (1R,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) to (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]hept-3-one (25);

[0258] Converting (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]heptan-3-one (25) to (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3,6-dione (5);

[0259] Converting (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5) to (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6);

[0260] Converting (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) to (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7);

[0261] Converting (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) to (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8);

[0262] converting (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) to (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19); and

[0263] (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) is converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1), optionally followed by acidification to provide its hydrochloride salt.

[0264] 15. A process according to claim 14, wherein (1R,4S)-(-)-2-azabicyclo[2.2.1]hept-5-en-3-one (2) is reacted with 4-methoxybenzyl chloride, tetrabutylammonium iodide and lithium bis(trimethylsilyl)amide to produce (1R,4S)-(-)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3).

[0265] 16. A process according to claim 14, wherein (1R,4S)-(-)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) is reacted with 1,3-dibromo-5,5-dimethylhydantoin to produce (1R,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4).

[0266] 17. A process according to claim 14, wherein (1R,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) is reacted with potassium carbonate in methanol to produce (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]hept-3-one (25).

[0267] 18. A process according to claim 14, wherein (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]hept-3-one (25) is reacted with oxalyl chloride in dichloromethane, DMSO and triethylamine to produce (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5).

[0268] 19. A process according to claim 14, wherein (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]hept-3-one (25) is reacted with 4-methylmorpholine-N-oxide in dichloromethane and tetrapropylammonium perruthenate to produce (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5).

[0269] 20. A process according to claim 14, wherein (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5) is reacted with 2-((difluoromethyl)sulfinyl)pyridine (20) and potassium bis(trimethylsilyl)amide in DMF and quenched with NH4Cl to produce (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6).

[0270] 21. A process according to claim 14, wherein (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) in acetonitrile is reacted with ammonium cerium(IV) nitrate, MeCN, and H2O to produce (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7).

[0271] 22. A process according to claim 14, wherein (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) is reacted with Boc2O, DMAP, Et3N, and CH2Cl2 to produce (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8).

[0272] 23. A process according to claim 14, wherein (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) is reacted with K2CO3, methanol or ethanol to produce (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19).

[0273] 24. A process according to claim 14, wherein (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) is reacted with HCl to produce (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof.

[0274] 25. (S)-3-Amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof prepared by the process according to item 1.

[0275] 26. (S)-3-Amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof prepared by the process according to item 12.

[0276] 27. (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) or a pharmaceutically acceptable salt thereof.

[0277] 28. (1R,4R,7R)-7-Bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) or a pharmaceutically acceptable salt thereof.

[0278] 29. Methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (8) or a pharmaceutically acceptable salt thereof.

[0279] 30. Methyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (9) or a pharmaceutically acceptable salt thereof.

[0280] 31. (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) or a pharmaceutically acceptable salt thereof.

[0281] 32. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and one or more of the following compounds: (1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one (2), (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one, -3-one (3), (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4), (1R,4R,6S,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (25), (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate 1,6-dione (5), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6), (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7), (1R,4R,7R)-7-bromo- 6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8), or (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9), (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19), or a pharmaceutically acceptable salt of any of the foregoing compounds.

[0282] 33. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one (2) or a pharmaceutically acceptable salt thereof.

[0283] 34. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (1R,4S)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) or a pharmaceutically acceptable salt thereof.

[0284] 35. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (1R,4R,6S,7R)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) or a pharmaceutically acceptable salt thereof.

[0285] 36. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (1R,4R,7R)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (25) or a pharmaceutically acceptable salt thereof.

[0286] 37. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (1R,4R,7R)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptane-3,6-dione (5) or a pharmaceutically acceptable salt thereof.

[0287] 38. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) or a pharmaceutically acceptable salt thereof.

[0288] 39. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) or a pharmaceutically acceptable salt thereof.

[0289] 40. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (1R,4R,7R)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) or a pharmaceutically acceptable salt thereof.

[0290] 41. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid methyl ester (9) or a pharmaceutically acceptable salt thereof.

[0291] 42. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid ethyl ester or a pharmaceutically acceptable salt thereof.

[0292] 43. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid or a pharmaceutically acceptable salt thereof.

[0293] 44. A process for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a salt thereof, comprising:

[0294] Converting cyclopent-3-ene-carboxylic acid ethyl ester (10) to (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11);

[0295] Converting (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11) to (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12);

[0296] Conversion of (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester to (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (13);

[0297] Converting (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (13) to (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14);

[0298] converting (S)-ethyl 9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14) to (S)-ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15); and

[0299] (S)-Ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) was converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1).

[0300] 45. The process according to item 44, wherein cyclopent-3-ene-carboxylic acid ethyl ester (10) is converted to (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11) by Sharpless aminohydroxylation and Boc protection.

[0301] 46. ​​The process according to item 44, wherein ethyl (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylate (11) is converted into ethyl (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylate (12) by oxidation.

[0302] 47. A process according to item 44, wherein (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12) is protected and converted to (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (13).

[0303] 48. A process according to item 44, wherein ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) is subjected to phenylselenium bromide, base and H2O2 to produce ethyl (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14).

[0304] 49. A process according to claim 44, wherein (S)-ethyl 9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylate (14) is deprotected and subjected to a Horner-Wittig reaction to produce ethyl (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15).

[0305] 50. A process according to item 44, wherein (S)-ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) is converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) using trifluoroacetic acid (TFA), dichloromethane (DCM) and saturated NaHCO3.

[0306] 51. (S)-3-Amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof prepared by the process according to item 44.

[0307] 52. Ethyl (9S)-9-(tert-Butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) or a pharmaceutically acceptable salt thereof.

[0308] 53. (S)-9-(tert-Butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14) or a pharmaceutically acceptable salt thereof.

[0309] 54. (S)-Ethyl 3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylate (15) or a pharmaceutically acceptable salt thereof.

[0310] 55. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and one or more of the following compounds: cyclopent-3-ene-carboxylic acid ethyl ester (10), (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11), (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12), 4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (12), (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylic acid ethyl ester (13), (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14), (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid ethyl ester (15), or a pharmaceutically acceptable salt of any of the foregoing compounds.

[0311] 56. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of cyclopent-3-ene-carboxylic acid ethyl ester (10) or a pharmaceutically acceptable salt thereof.

[0312] 57. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of cyclopent-3-ene-carboxylic acid ethyl ester (10), (3R,4S)-3-((tert-butoxycarbonyl)amino)-4-(hydroxy)cyclopentanecarboxylic acid ethyl ester (11) or a pharmaceutically acceptable salt thereof.

[0313] 58. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (3R)-3-((tert-butoxycarbonyl)amino)-4-oxo-cyclopentanecarboxylic acid ethyl ester (12) or a pharmaceutically acceptable salt thereof.

[0314] 59. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of ethyl (9S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonanecarboxylate (13) or a pharmaceutically acceptable salt thereof.

[0315] 60. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (S)-9-(tert-butoxycarbonylamino)-1,4-dioxa-7-spiro[4.4]nonene-7-carboxylic acid ethyl ester (14) or a pharmaceutically acceptable salt thereof.

[0316] 61. A pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof and from 0.0001 mg to 1 mg of (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid ethyl ester (15) or a pharmaceutically acceptable salt thereof.

Claims

1. A process for preparing (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a salt thereof, comprising: (1R,4S)-(-)-2-azabicyclo[ 2.2.1]hept-5-en-3-one (2) is converted to (1R,4S)-(-)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3); Converting (1R,4S)-(-)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) to (1R,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4); Converting (1R,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) to (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]hept-3-one (25); Converting (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]heptan-3-one (25) to (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3,6-dione (5); Converting (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5) to (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6); Converting (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) to (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7); Converting (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) to (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8); converting (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) to (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19); and (S)-3-((tert-Butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) is converted to (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1), optionally followed by acidification to provide its hydrochloride salt.

2. The process according to claim 1, wherein (1R,4S)-2-azabicyclo[2.2.1]hept-5-en-3-one (2) is reacted with 4-methoxybenzyl chloride, tetrabutylammonium iodide and lithium bis(trimethylsilyl)amide to produce (1R,4S)-(-)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3).

3. The process according to claim 1, wherein (1R,4S)-(-)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-5-en-3-one (3) is reacted with 1,3-dibromo-5,5-dimethylhydantoin to produce (1R,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4).

4. The process according to claim 1, wherein (1R,4R,6S,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-3-oxo-2-azabicyclo[2.2.1]hept-6-yl acetate (4) is reacted with potassium carbonate in methanol to produce (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]hept-3-one (25).

5. The process of claim 1 , wherein (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]hept-3-one (25) is reacted with oxalyl chloride in dichloromethane, DMSO and triethylamine to produce (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5).

6. A process according to claim 1, wherein (1R,4R,6S,7R)-(+)-7-bromo-6-hydroxy-2-(4-methoxybenzyl)-2-aza-bicyclo[2.2.1]heptan-3-one (25) is reacted with 4-methylmorpholine-N-oxide in dichloromethane and tetrapropylammonium perruthenate to produce (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3,6-dione (5).

7. A process according to claim 1, wherein (1R,4R,7R)-(+)-7-bromo-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3,6-dione (5) is reacted with 2-((difluoromethyl)sulfinyl)pyridine (20) and potassium bis(trimethylsilyl)amide in DMF and quenched with NH4Cl to produce (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]hept-3-one (6).

8. The process of claim 1, wherein (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(4-methoxybenzyl)-2-azabicyclo[2.2.1]heptan-3-one (6) in acetonitrile is reacted with ammonium cerium(IV) nitrate, MeCN, and H2O to produce (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7).

9. The process of claim 1, wherein (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-azabicyclo[2.2.1]heptan-3-one (7) is reacted with Boc2O, DMAP, Et3N, CH2Cl2 to produce (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8).

10. The process of claim 1, wherein (1R,4R,7R)-(+)-7-bromo-6-(difluoromethylene)-2-(tert-butoxycarbonyl)-2-azabicyclo[2.2.1]heptan-3-one (8) is reacted with K2CO3, methanol or ethanol to produce (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19).

11. The process of claim 1 , wherein (S)-3-((tert-butoxycarbonyl)amino)-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (19) is reacted with HCl to produce (S)-3-amino-4-(difluoromethylene)cyclopent-1-ene-1-carboxylic acid (1) or a pharmaceutically acceptable salt thereof.

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