Sulfuric Acid → HCID 18988341, compound

Participants

Reaction Conditions

Reaction Steps

To a stirred and cooled (-10° C.) amount of 180 parts of sulfuric acid there were added portionwise 24.0 parts of 5-(3-chlorophenyl)-6,7-dihydro-5H-pyrrolo[1,2-c]imidazole mononitrate (described in U.S. Pat. No. 4,617,307). Stirring at 0° to -10° C. was continued for 2 hours. After cooling to -78° C., the mixture was diluted with 100 parts of water and then neutralized with a solution of 141 parts of NaOH in 200 parts of water, keeping the temperature below 28° C. The whole was basified to pH 9 with an excess of Na2CO3 10% and was filtered when reached room temperature. The precipitate was washed with dichloromethane and the filtrate layers were separated. The aqueous layer was diluted with 100 parts of water and the whole was re-extracted with dichloromethane (4×399 parts). The combined dichloromethane layers were washed with NaCl (sat.), dried, filtered and evaporated, yielding 17.1 parts (75.9%) of 5-(3-chloro-4-nitrophenyl)-6,7-dihydro-5H-pyrrolo[1,2-c]imidazole (interm. 35).

Provenance & Evidence