Carbon Dioxide → HCID 86753964, compound

Participants

Reaction Steps

A suspension of 11.3 g (0.0437 mol) of 5-methyl-6-oxo-5,6-dihydro-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylic acid in 220 ml of dimethylformamide was treated portionwise with 7.80 g (0.048 mol) of carbonyldiimidazole while gassing with argon. After completion of the CO2 evolution the mixture was stirred at 55° for 2 hrs. After cooling to 0-5° the pale yellow solution obtained was treated with 7.48 g (0.0532 mol) of L-serine methyl ester hydrochloride and with 6.7 ml (0.048 mol) of triethylamine and stirred at room temperature for 70 hrs. The light suspension was completely freed from the solvents. The residue was dissolved in hot water and extracted continuously with ethyl acetate. The yellow oily residue was chromatographed over silica gel with ethyl acetate as the eluent. There were obtained 10.7 g (68%) of methyl (S)-3-hydroxy-2-(5-methyl-6-oxo-5,6-dihydro-4H-imidazo[1,5-a][1,4]benzodiazepin-3-ylcarbonylamino)-propionate as a white solid. An analytical sample was recrystallized from ethyl acetate/diethyl ether and gave white crystals; m.p. 180-181°. [α]D20 =+12.9° (CHCl3, c=1%).

Provenance & Evidence