反应详情

Scheme 11 shows the synthesis of 5-(2-(4-bromo-2-fluorophenyl)-1H-imidazol-4-yl)-1-isopropyl-3-methyl-1H-1,2,4-triazole V from 4-bromo-2-fluorobenzimidamide hydrochloride 12. 3-Chloro-2-oxopropanoic acid and 12 are reacted with base to give 2-(4-bromo-2-fluorophenyl)-1H-imidazole-4-carboxylic acid 30. Alternatively, 3-bromo-2-oxopropanoic acid can be reacted with 12 to give 30. Reaction of 30 with N′-isopropylacetohydrazonamide 6 and coupling reagent HBTU (N,N,N′,N′-tetramethyl-O-(1H-benzotriazol-1-yl)uronium hexafluorophosphate, 0-(Benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate, CAS Ref No. 94790-37-1) in DMF gives intermediate, 2-(4-bromo-2-fluorophenyl)-N-(1-(2-isopropylhydrazinyl)ethylidene)-1H-imidazole-4-carboxamide 31 which need not be isolated and cyclizes upon heating to give V. Alternatively, 5-(2-(4-chloro-2-fluorophenyl)-1H-imidazol-4-yl)-1-isopropyl-3-methyl-1H-1,2,4-triazole 44, the chloro version of V, can be prepared from 4-chloro-2-fluorobenzonitrile 38 (Scheme 15)