Citric Acid → HCID 67263712, compound

Participants

Reaction Steps

To a slurry of 7-methoxy-8-nitro-1,3,4,5-tetrahydro-benzo[e][1,4]diazepin-2-one (100 mg, 0.42 mmol) in dichloromethane (10 mL) was syringed N,N-diisopropylethylamine (0.15 mL, 0.84 mmol). The mixture was cooled in an ice-water bath and acetyl chloride (0.04 mL, 0.55 mmol) was added via syringe. After 15 minutes LCMS indicated completion of the reaction. Dichloromethane (10 mL) and 10% aqueous citric acid (10 mL) were added and the mixture was stirred while being allowed to warm to room temperature. The mixture was filtered and the collected solid was washed with water and dried to constant weight to give 4-acetyl-7-methoxy-8-nitro-1,3,4,5-tetrahydro-benzo[e][1,4]diazepin-2-one (70 mg, 60%) as a yellow solid. NMR analysis indicated a mixture of two conformational isomers, similar to that observed for the related trifluoroacetyl analog (see procedure 6c); NMR (400 MHz, DMSO-d6) δ 10.19/10.17 (2s, 1H), 7.69/7.66 (2s, 1H), 7.46/7.35 (2s, 1H), 4.78/4.67 (2s, 2H), 4.36/4.37 (2s, 2H), 3.90/3.92 (2s, 3H), 2.05 (s, 3H); MS (m/e) 278 (M−1); mp 266° C. (dec.).

Provenance & Evidence