Methanesulfonic Acid → 3-amino-8-bromo-1,5-dimethyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one

Participants

Reaction Conditions

Reaction Steps

162c (0.831 g, 2.00 mmol) was dissolved in anhydrous anisole (16 ml) and then methane sulfonic acid (3.84 g, 40 mmol) was added in one portion, and then the reaction was heated to 40° C. for 30 minutes with stirring. The reaction was cooled to 0° C. in an ice bath then basified to pH=10 with concentrated ammonium hydroxide. The aqueous solution was then extracted with chloroform (3×50 ml) and the organic layers combined, dried over magnesium sulfate, filtered and the filtrate concentrated to give a residue. The residue was purified to silica gel column chromatography eluting with 10% methyl alcohol in chloroform to give the title compound 162d (0.463 g, 82%). 1H NMR (CDCl3, 300 MHz): δ 7.32-7.23 (m, 3H), 4.12 (d, 1H, J=1.1 Hz), 3.27 (s, 3H), 2.30 (d, 3H, J=1.5 Hz) ppm.

Provenance & Evidence