p-Toluenesulfonic acid → Desmethylnitrazolam

Participants

Reaction Steps

2-Hydrazino-7-nitro-5-phenyl-3H-1,4-benzodiazepine prepared from 5.6 parts of 2-amino-7-nitro-5-phenyl-3H-1,4-benzodiazepine in a similar manner to Example 7, is dissolved in a mixture of 20 parts by volume of ethyl orthoformate and 100 parts by volume of chloroform, followed by the addition of 10 parts of p-toluenesulfonic acid. The whole mixture is left standing at room temperature for 1 hour with occasional shaking. After completion of the reaction, the solution is washed with a saturated aqueous solution of sodium bicarbonate, then with water, and dried over sodium sulfate. After evaporation of the solvent, the residue is treated with ethyl acetate, whereby 8-nitro-6-phenyl-4H-s-triazolo [4,3-a][1,4] benzodiazepine is yielded as crystals. Recrystallization from tetrahydrofuran yields pale yellow needles melting at 271° C to 272° C.

Provenance & Evidence