3-Amino-5-methylisoxazole → 1-Oxo-N-(3-phenyl-1,2-oxazol-5-yl)-2,3,4,5-tetrahydro-1H-[1,4]diazepino[1,2-a]benzimidazole-8-carboxamide

Participants

Reaction Steps

A solution of 1-oxo-2,3,4,5-tetrahydro-1H-[1,4]diazepino[1,2-a]benzimidazole-8-carboxylic acid (Intermediate B, 71 mg, 0.29 mmol) and 1,1′-carbonyldiimidazole (117 mg, 0.72 mmol) in THF (10 mL) is heated to 60° C. for 1 h. The solution is cooled to room temperature and 5-methyl-3-aminoisoxazole (191 mg, 1.16 mmol) is added. After 10 min DBU (0.11 mL, 0.72 mmol) is added and the mixture heated at 60° C. for 16 h. The solvent is evaporated and H2O is added to the residue. The resulting solid is collected by filtration and is purified via preparative HPLC to afford the title compound (17 mg, 12%).

Provenance & Evidence