Trifluoroacetic acid → benzyl (4S,10aS)-5-oxooctahydro-2H-pyrido[2,1-b][1,3]thiazepin-4-ylcarbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-benzyl 4-mercapto-1-oxo-1-(5-oxopentylamino)butan-2-ylcarbamate (150 mg, 0.426 mmol) in DCM (5 mL) at rt was added a couple drops of TFA (by pipette). The mixture was stirred at 50° C. (gentle refluxing) for 1.5 hr. The reaction mixture was cooled to rt and concentrated. The residue was diluted with EtOAc. The EtOAc solution was washed with saturated aqueous NaHCO3, saturated aqueous NaCl (2×), dried over Na2SO4, filtered and concentrated. The residue was purified using silica gel chromatography (ISCO system) eluting with a gradient of 0-70% EtOAc/Hex to give benzyl (4S,10aS)-5-oxooctahydro-2H-pyrido[2,1-b][1,3]thiazepin-4-ylcarbamate (115 mg, 0.344 mmol, 81% yield). Anal. Calcd. for C12H22N2O3S m/z 334.3. found: 335.3 (M+H)+; 1H NMR (400 MHz, CDCl3) δ ppm 7.43-7.26 (m, 5H), 6.25 (d, J=6.5 Hz, 1H), 5.28 (dd, J=7.7, 3.0 Hz, 1H), 5.10 (d, J=2.5 Hz, 2H), 4.86 (ddd, J=10.3, 6.8, 3.3 Hz, 1H), 4.28 (d, J=13.8 Hz, 1H), 3.19 (ddd, J=14.1, 11.0, 2.7 Hz, 1H), 3.07-2.87 (m, 1H), 2.70 (ddd, J=14.4, 6.1, 3.0 Hz, 1H), 2.44-2.25 (m, 1H), 2.06-1.89 (m, 2H), 1.86-1.60 (m, 3H), 1.60-1.39 (m, 2H).

Provenance & Evidence