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

Participants

Reaction Steps

A mixture of 1-oxo-2,3,4,5-tetrahydro-1H-[1,4]diazepino[1,2-a]benzimidazole-8-carboxylic acid (Intermediate B, 51 mg, 0.21 mmol) and HATU (89 mg, 0.23 mmol) in dichloroethane (3 mL) is stirred at room temperature for 1 h. 2-tert-Butylimino-2-diethylamino-1,3-dimethyl-perhydro-1,3,2-diazaphosphorine on polystyrene (64 mg, 0.64 mmol) is added and the mixture is stirred at room temperature for 10 min. 5-Methyl-3-aminoisoxazole (62 mg, 0.64 mmol) is added and the reaction is stirred at 60° C. for 16 h and is cooled to room temperature. The mixture is diluted with methanol, filtered and evaporated. The residue is purified via flash column chromatography using a gradient elution of 0-10% CH2Cl2/methanol and is triturated with CH2Cl2 (3 mL), filtered and dried to afford the title compound (25 mg, 36%).

Provenance & Evidence