Hydrochloric Acid → N9-(3,5-dichloro-4-pyridyl)-6-difluoromethoxy-3-ethyl-4-oxo-3,4-dihydro benzo[4,5]furo[2,3-d]pyridazine-9-carboxamide

Participants

Reaction Conditions

Reaction Steps

A suspension of 4-nitrophenyl 6-difluoromethoxy-3-ethyl-4-oxo-3,4-dihydrobenzo[4,5]furo[2,3-d]pyridazine-9-carboxylate (from step III) (81 mg, 0.18 mmol) and 4-amino-3,5-dichloro pyridine (32 mg, 0.19 mmol) in dimethyl formamide (3 ml) was cooled to −30-40° C. under nitrogen. Then sodium hydride (15 mg, 0.36 mmol) was added lotwise at the same temp. under nitrogen. Progress of reaction was monitored by TLC. At the end, reaction mixture was cooled to 0-10° C. Water (100 ml) was added dropwise to the reaction mixture at 0-10° C. and acidified with dilute HCl. the precipitate obtained was filtered and dried in oven. The solid was purified by column chromatography using 20% acetone in chloroform. 178 mg pure product was obtained as off white solid.

Provenance & Evidence