Phosphorus oxychloride → 6-Bromo-1-chlorophthalazine

Participants

Reaction Steps

A mixture of 6-bromophthalazin-1(2H)-one (17, 2.6 g, 12 mmol) in phosphorous oxychloride (11 mL, 116 mmol) was treated with diisopropylethylamine (2.0 mL, 12 mmol). The mixture was stirred at room temperature for 30 min, then warmed up to a temperature of between about 95-100° C. and stirred under nitrogen. The suspension (reaction) became a deep brown solution in about 30 min, then a yellow solid precipitated out. After about 3 h, all of the starting material was converted, as appeared by TLC, to product (M+1=243, 245). After the mixture was cooled down to room temperature, it was diluted with 50 mL CHCl3 and cooled down to 0° C. The precipitate was filtrated, washed with 10 mL ice cool CHCl3, collected and dried under vacuum, to afford 1.96 g of 6-bromo-1-chlorophthalazine 18, as yellow solid. Found MS (ES+): 243, 245 (M+H)+.

Provenance & Evidence