Boron tribromide → 2-[(4S)-6-(4-chlorophenyl)-8-hydroxy-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepin-4-yl]-N-ethylacetamide

Participants

Reaction Conditions

Reaction Steps

2-[(4S)-6-(4-Chlorophenyl)-1-methyl-8-(methyloxy)-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepin-4-yl]-N-ethylacetamide (which may be prepared, for example, by reaction of Reference compound H with ethylamine) (0.424 g) was dissolved in DCM (8 ml) and cooled to −78° C. A solution of boron tribromide (0.945 ml) in DCM (2 ml) was added slowly to the reaction mixture. The reaction was stirred at −78° C. for 35 min under nitrogen and then at room temperature for 2.5 h. The reaction was quenched by adding a solution of ethanol (1 ml) in DCM (5 ml) dropwise. The solvent was evaporated and the residue was chromatographed (0-10% methanol:DCM) to give 2-[(4S)-6-(4-chlorophenyl)-8-hydroxy-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepin-4-yl]-N-ethylacetamide as a yellow solid. The aqueous layer was passed through a pre equilibrated Biotage 103 column, the organic content was eluted with methanol and the methanolic solution was evaporated to give a further quantity of 2-[(4S)-6-(4-chlorophenyl)-8-hydroxy-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepin-4-yl]-N-ethylacetamide as a yellow solid (total yield 271.3 mg).

Provenance & Evidence