Sulfuric Acid → HCID 69998297, compound

Participants

Reaction Steps

To conc H2SO4 (14 ml), kept in an ice bath, KNO3 (2 g, 20 mmol) was added in portions whereby the temperature rose to 10° C. (see also R. I. Fryer et al., J. Heterocyclic Chem. 1991, 28, 1203-1208). To this mixture was added a solution of (1-methyl-2,5-dioxo-1,2,3,5-tetrahydro-benzo[e][1,4]diazepin-4-yl)-acetic acid ethyl ester (5 g, 18 mmol) in dichloromethane (16 ml) whereby the temperature was kept between 20-25° C. After stirring for 90 min the mixture was carefully poured onto ice water and extracted with dichloromethane. The organic extracts were washed with aqueous sat. NaHCO3 followed by water, dried over Na2SO4 and the solvents evaporated. Upon addition of EtOH to the oily residue a precipitate was formed which was collected by filtration to give (1-methyl-7-nitro-2,5-dioxo-1,2,3,5-tetrahydro-benzo[e][1,4]diazepin-4-yl)-acetic acid ethyl ester (4 g): mp. 129-130° C.; MS (EI): 321 (M)+.

Provenance & Evidence