p-Toluenesulfonic acid → (+/-)-8-Methyl-7-(5-methyl-1,3,4-thiadiazol-2-yl)-5-(4-nitrophenyl)-8,9-dihydro-7H-1,3-dioxolo[4,5-h][2,3]benzodiazepine

Participants

Reaction Steps

To an ice cooled stirred mixture of 1.0 g (2.50 mmol) of the starting material XVIII, 35 ml of dichloromethane, 0.40 ml (2.75 mmol) of triethylamine and 0.22 ml (2.80 mmol) of acetyl chloride was added. The so obtained solution was left at room temperature for 16 h, then 0.6 g of p-toluenesulfonic acid was added and the mire was stirred at 40° C. for 2 h. Then the reaction mixture was washed with sodium hydrogen carbonate solution and water until neutrality, dried and concentrated. The crude product was treated with methanol, then recrystallized from ethanol to yield 0.99 g (91%) of the title compound. Mp.: 213-215° C.

Provenance & Evidence