Hydrochloric Acid → (1aR,5aR)-2-(4-chloro-pyridin-2-yl)-1a,2,5,5a-tetrahydro-1H-2,3-diaza-cyclopropa[a]pentalene-4-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of (1aR,5aR)-2-(4-iodo-pyridin-2-yl)-1a,2,5,5a-tetrahydro-1H-2,3-diaza-cyclopropa[a]pentalene-4-carboxylic acid ethyl ester (1.0 g, 2.53 mmol) in acetonitrile (30 mL) was added concentrated HCl solution (2 mL). The reaction was stirred at 80° C. for 20 h. After removal of acetonitrile, the aqueous residue was diluted with water and a NaHCO3 solution was added to adjust the pH to 2-3. The resulting mixture was extracted with EtOAc (100 mL). The organic layer was washed with brine, dried over MgSO4, and concentrated. The residue was dissolved in a mixture of THF/MeOH/H2O (20/20/10) and added LiOH (61 mg). The reaction was stirred overnight and concentrated. The aqueous residue was diluted with water and an HCl solution was added to adjust the pH to 2-3. The resulting solid was filtered, washed with water and dried to give the title compound (610 mg). LCMS m/z=276.1 [M+H]+; 1H NMR (400 MHz, DMSO-d6) δ 0.40 (dd, J=7.7, 4.5 Hz, 1H), 1.25 (td, J=7.9, 4.6 Hz, 1H), 2.25-2.30 (m, 1H), 2.71-2.75 (m, 1H), 2.76 (d, J=16.8 Hz, 1H), 2.87 (dd, J=16.4, 6.4 Hz, 1H), 7.55 (dd, J=5.4, 1.9 Hz, 1H), 7.90 (d, J=1.8 Hz, 1H), 8.52 (d, J=5.4 Hz, 1H), 12.98 (s, 1H).

Provenance & Evidence