Oxalyl chloride → 4-(3-Methyl-1-pyrazolyl)-2-chlorobenzoyl chloride

Participants

Reaction Steps

Step e) [2-Chloro-4-(3-methylpyrazol-1-yl)-phenyl]-(3-methyl-5H, 11H-pyrrolo[2,1-c][1,4]-benzodiazepin-10-yl)-methanone: A mixture of 2-chloro-4-(3-methylpyrazol-1-yl)-benzoic acid (0.18 g) from step d), oxalyl chloride (0.18 g) and one drop of dimethylformamide in dichloromethane (10 ml), was stirred at room temperature for 18 hours. The mixture was concentrated in vacuo, and the residue was redissolved in dichloromethane and reconcentrated in vacuo to yield 2-chloro-4-(3-methyl-pyrazol-1-yl)-benzoyl chloride. A slurry of the acid chloride in dichloromethane (25 ml) was added dropwise to a solution of 10,11-dihydro-3-methyl-5H-pyrrolo[2,1-c][1,4]benzodiazepine (0.12 g) and diisopropylethylamine (0.10 g) in dichloromethane (25 ml). The mixture was stirred at room temperature for 18 h, and washed with water and saturated aqueous sodium bicarbonate. The organic phase was dried over anhydrous sodium sulfate and filtered through a short column of anhydrous sodium magnesium silicate. The solution was concentrated in vacuo and triturated with diethyl ether to yield 0.115 g of product as colorless crystals, m.p. 178-180° C., MS m/z: 417.3 (M+H)+, 833.3 (2M+H)+.

Provenance & Evidence