(Phenylmethyl)hydrazine → HCID 178519612, compound

Participants

Reaction Steps

1-Benzyl-3-(5-carboxy-2-furyl)indazole, potassium salt: 70.26 g (0.3 mol) of 5-(2-fluorobenzoyl)furan-2-carboxylic acid were initially charged in 350 ml of methanol, 109.95 g (0.9 mol) of benzylhydrazine were added and the mixture was, after addition of 8 ml of glacial acetic acid, heated under reflux for 6 h. For work-up, the mixture was concentrated using a rotary evaporator, the residue was taken up in 2 N aqueous sodium hydroxide solution and extracted with ethyl acetate. The aqueous phase was acidified with 2 N hydrochloric acid and extracted with ethyl acetate. The residue that remained after drying and concentration using a rotary evaporator was recrystallized from ethyl acetate/n-hexane. The 68.3 g (0.20 mol) of 5-(2-fluorobenzoyl)furan-2-carboxylic acid benzylhydrazone (m.p.: 147° C. (decomp.)) obtained in this manner were dissolved in 400 ml of DMF, 45.38 g (0.40 mol) of potassium tert-butoxide were introduced and the mixture was heated under reflux for 30 minutes. The precipitate was filtered off with suction, washed with dichloromethane and recrystallized from ethanol/water (95:5). This gave 57.7 g (54%) of the title compound. The corresponding cyclization of the precursor which was still contained in the mother liquor gave 25.9 g of product. m.p.: >300° C.

Provenance & Evidence