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

Participants

Reaction Conditions

Reaction Steps

The product of Step 3 (0.831 g, 2.00 mmol) was dissolved in anhydrous anisole (16 ml) and then methanesulfonic acid (3.84 g, 40 mmol) was added in one portion. The reaction mixture was heated to 40° C. for 30 minutes with stirring, then cooled to 0° C. in an ice bath and made basic (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 concentrated to give the crude product. Purification on silica gel, eluting with 10% methyl alcohol in chloroform, providing the title compound as an XXXX (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