Hydrogen Bromide → alpha-Hydroxyalprazolam

Participants

Reaction Steps

An amount of 25 g of 1-(benzyloxymethyl)-6-phenyl-8-chloro-4H-s-triazolo[4,3-a][1,4]benzodiazepine is dissolved in 200 ml of glacial acetic acid; to this solution are then added 170 ml of 48% aqueous hydrobromic acid. The mixture is heated for 90 minutes at 80°, and afterwards cooled to 5°; the pH-value of the mixture is adjusted with concentrated sodium hydroxide solution to 6, whilst stirring is maintained, and water and also methylene chloride are then added. The organic phase is separated, washed with saturated aqueous sodium chloride solution, dried over sodium sulphate, and concentrated by evaporation. The residue is dissolved in ethyl acetate/methanol (9:1), the solution filtered through a column of 150 g of silica gel (Merck®, particle size 0.05-0.2 mm), and the column eluted with ethyl acetate/methanol (9:1) to (7:3). The eluate is concentrated by evaporation and the residue crystallised from ethyl acetate/ether. In this manner is obtained 6-phenyl-8-chloro-4H-s-triazolo [ 4,3-a][1,4]benzodiazepine-1-methanol, M.P. 210°-211°.

Provenance & Evidence