o-Xylyl bromide → (Z)-7-Chloro-5-(4-methoxyphenyl)-1-methyl-3-(2-methylbenzyl)-1H-benzo[e][1,4]diazepin-2(3H)-one

Participants

Reaction Steps

To a stirred and cooled (dry ice/acetone bath) solution of (Z)-7-chloro-5-(4-methoxyphenyl)-1-methyl-1H-benzo[e][1,4]diazepin-2(3H)-one (0.50 g, 1.59 mmol) in THF (8 mL) was slowly added 1 M KOtBu (2.4 mL, 2.4 mmol, 1.5 eq). The resulting deep red mixture was stirred over dry ice/acetone bath ˜10 min followed by the slow addition of a solution of 2-methylbenzyl bromide (0.46 g, 2.5 mmol, 1.5 eq) in THF (2 mL). After stirring another ˜35 min at −78° C., the reaction mixture was quenched with water and diluted with EtOAc. The organic layer was dried (Na2SO4), filtered and evaporated (rotovap, then high vacuum). Chromatography over silica gel using 20-40% EtOAc/heptane gave 0.56 g (yield of 84%) of the title product [Note: when using benzyl chlorides as alkylating agents, tetrabutyl ammonium iodide was added along with the alkylating agent at the low temperature]. 1H NMR (300 MHz, CDCl3) δ 2.38 (s, 3H), 3.41 (s, 3H), 3.5-3.65 (m, 2H), 3.74 (dd, 1H), 3.84 (s, 3H), 6.89 (dt, 2 H), 7.05-7.15 (m, 3H), 7.25-7.35 (m, 3H), 7.45-7.5 (m, 3H).

Provenance & Evidence