Hydrochloric Acid → HCID 54498678, compound

Synthesis of Compound (2) Dibromide 1 (5.7 g, 22.3 mmol), ethyl cyanoacetate (4.8 mL, 44.5 mmol) and potassium carbonate (6.15 g, 44.5 mmol) were stirred together in DMF (100 mL) for 48 hours. Dilute hydrochloric acid (100 mL) was added, and the mixture was extracted with ether (3×100 mL). The combined organic fractions were washed with brine, dried (MgSO4), and the solvent was evaporated under reduced pressure. The residue was chromatographed (SiO2, heptane-ethyl acetate, 98:2) to give the cyanoester 2 (4.3 g, 100%) as a 68:32 mixture of diastereoisomers: Rf(heptane-ethyl acetate, 9:1) 0.28; νmax(film)/cm−1 2241 (CN), 1741 (C═O); Major diastereoisomer: δH(400 MHz; CDCl3) 4.30 (2H, q, J 7.1, CO2CH2Me), 2.98 (2H, m), 2.56–2.22 (6H, m), 1.70 (2H, m), 1.35 (3H, t, J 7.1, Me); Minor diastereoisomer: δH (400 MHz; CDCl3) 4.26 (2H, q, J 7.1, CO2CH2Me), 3.05 (2H, m), 2.56–2.22 (6H, m), 1.99 (2H, m), 1.33 (3H, t, J 7.1, Me). Synthesis of Compound (3) Cyanoester 2 (0.76 g, 3.91 mmol), water (0.14 mL, 7.82 mmol) and lithium chloride (0.66 g, 15.6 mmol) were heated to 150° C. in DMSO (40 mL) for 22 hours. The mixture was allowed to cool, diluted with water (150 mL), and extracted with ether (3×50 mL). The combined ether fractions were washed with brine, dried (MgSO4), and the solvent was evaporated under reduced pressure. The residue was chromatographed (SiO2, heptane-ethyl acetate, 95:5) to give the cyanide 3 (0.21 g, 44%) as a 60:40 mixture of diastereoisomers; Rf(heptane-ethyl acetate, 9:1) 0.44; νmax(film)/cm−1 2238 (CN); Major diastereoisomer: δH (400 MHz; CDCl3) 2.97 (1H, m), 2.87 (2H, m), 2.32–2.18 (2H, m), 2.10–1.96 (3H, m), 1.92–1.78 (2H, m), 1.48–1.38 (1H, m); Minor diastereoisomer: δH (400 MHz; CDCl3) 3.13 (1H, m), 2.87 (2H, m), 2.32–2.18 (2H, m), 2.10–1.96 (3H, m), 1.92–1.78 (2H, m), 1.48–1.38 (1H, m). Synthesis of Compound (4) Cyanide 3 (0.86 g, 7.1 mmol) in THF (30 mL) was added dropwise over 1 hour to a stirring mixture of lithium hexamethyldisilazide (7.8 mL of a 1 M solution in THF, 7.8 mmol) in THF (40 mL) at −78° C. under argon. The mixture was allowed to warm to −40° C. and stirred for 2 hours. The mixture was cooled to −78° C. and dimethylallyl bromide (1.3 mL, 10.6 mmol) was added. The mixture was stirred for a further 2 hours at −78° C. and then allowed to warm to room temperature overnight. Saturated ammonium chloride solution (20 mL) was added, and the mixture was diluted with ether (50 mL) and dilute hydrochloric acid (30 mL). The aqueous layer was further extracted with ether (2×50 mL), and the combined 15 organic fractions were washed with brine, dried (MgSO4), and the solvent was evaporated under reduced pressure. The residue was chromatographed (SiO2, heptane-ethyl acetate, 98:2) to give the cyanoalkene 4 (0.96 g, 72%) as a colorless oil; Rf(heptane-ethyl acetate, 95:5) 0.38; νmax(film)/cm−1 2230 (CN), 1673 (C═C); δH (400 MHz; CDCl3) 5.27 (1H, tt, J 7.6, 1.3, CHCMe2), 2.89 (2H, m), 2.30–2.22 (4H, m), 2.10 (2H, d, J 14.2), 1.94 (2H, m), 1.84–1.62 (2H, m), 1.65 (3H, s, Me), 1.55 (3H, s, Me); m/z (AP+) 190 (M+H, 100%). Synthesis of Compound (5) Cyanoalkene 4 (0.96 g, 5.1 mmol) and sodium hydroxide (10.2 mL of a 2.5 M solution in methanol, 25.5 mmol) were stirred together in dichloromethane (80 mL) at −78° C. Ozone was passed through the mixture which immediately went orange. After 2 hours, the mixture turned to a green color, and the solution was purged with oxygen for 5 minutes and then with nitrogen. The stirring mixture was diluted with ether (100 mL) and water (100 mL) and allowed to warm to room temperature overnight. The aqueous layer was further extracted with ether (2×50 mL), and the combined organic fractions were washed with brine, dried (MgSO4), and the solvent was evaporated under reduced pressure. The residue was chromatographed (SiO2, heptane-ethyl acetate, 95:5) to give the cyanoester 5 (0.70 g, 71%) as a yellow oil; Rf(heptane-ethyl acetate, 8:2) 0.36; νmax(film)/cm−1 2233 (CN), 1740 (C═O); δH (400 MHz; CDCl3) 3.75 (3H, s, OMe), 2.94 (2H, m), 2.63 (2H, s, CH2CO2Me), 2.35–2.21 (4H, m), 2.00 (2H, m), 1.86 (2H, m); m/z (AP+) 194 (M+H, 95%). Synthesis of Compound (6) Cyanoester 5 (0.81 g, 4.2 mmol) in methanol (100 mL) was shaken over a catalytic amount of nickel sponge catalyst under a hydrogen atmosphere (60 Psi, 30° C.) for 6 hours. The mixture was filtered, and the solvent was evaporated under reduced pressure to give lactam 6 (0.64 g, 92%) as a white solid; νmax(film)/cm−1 1692 (C═O); δH (400 MHz; CDCl3 5.52 (1H, br s, NH), 3.54 (2H, s, CH2NH), 2.80 (2H, m), 2.26 (2H, m), 2.16 (2H, s, CH2CO), 1.93 (2H, ddd, J 13.4, 8.1, 2.4), 1.74 (2H, dd, J 13.0, 3.2), 1.64 (2H, m). Synthesis of (1α,3β,5α)(3-Aminomethyl-bicyclo[3.2.0]hept 3-yl)-acetic acid hydrochloride (Example 41) Lactam 6 (0.64 g, 3.87 mmol) was dissolved in 1,4-dioxane (4 mL) and hydrochloric acid (16 mL of a 6N solution), and the mixture was refluxed for 6 hours. After cooling, the mixture was diluted with water (20 mL) and washed with dichloromethane (2×15 mL). The aqueous layer was evaporated under reduced pressure to give acid 7 (0.67 g, 79%) as a white solid. Recrystallization using ethyl acetate/methanol gave Example 41 exclusively (0.26 g); δH (400 MHz; d6-DMSO) 7.98 (2H, br s, NH2), 3.13 (2H, s, CH2NH2), 2.70 (2H, s), 2.17–2.14 (4H, m), 1.85 (2H, dd, J 13.3, 8.0), 1.63 (2H, m), 1.55 (2H, dd, J 12.9, 5.1); m/z (ES+) 184 (M+H, 100%); LCMS (Prodigy C18, 50 mm×4.6 mmid column, 5–50% Acetonitrile/water) Retention Time=2.40 minutes, 98% purity.

1. temperatureAfter cooling
2. washwashed with dichloromethane (2×15 mL)
3. customThe aqueous layer was evaporated under reduced pressure

ORD record

ord-eceec5f710dd4c43a5e3fbe01c1365b9

Source dataset

uspto-grants-2006_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07026505B2