Toluene → Alprazolam

Participants

Reaction Conditions

Reaction Steps

2-(2-acetyl hydrazino)-7-chloro-5-phenyl-2H-1,4 benzodiazepine (117.5 g; 0.36 mole) and toluene (11.75 mole.) were added to a RB flask. 0.94 mole of toluene was distilled out at 110-112° C. The reaction mixture was cooled to 90-95° C. and charged with p-toluene sulphonic acid (0.0012 mole). The reaction mixture was then refluxed at 105-110° C. for 10-12 hrs with a Dean-Stark apparatus for water removal. At the end of the reaction (as indicated by TLC), reaction mixture was cooled to 25-30° C. The reaction mass was then further cooled to 10-15° C. and stirred at same temperature for 4-5 hrs. The solids precipitated were filtered and washed with cold toluene to obtain crude 8-chloro-1-methyl-6-phenyl-4H-s-trizolo[4 3-I][1,4] benzodiazepine (alprazolam). The crude alprazolam was purified from isopropanol to obtain 80% yield of pure alprazolam.

Provenance & Evidence