Reaction Steps
A mixture of cesium carbonate (0.33 g, 0.82 mmol) and benzyl chloride (0.1 mL, 0.82 mmol) was added to a solution of 4-chloro-6-methyl-10,10-dioxo-2-piperazin-1-yl-10,11-dihydro-5-oxa-10lambda*6*-thia-dibenzo[a,d]cycloheptene-8-carboxylic acid methyl ester (free base of example 16, 0.3 g, 0.68 mmol) in DMF(10 mL) and heated at 80° C. for 5 h. Reaction mixture was concentrated, water (10 mL) was added and the solid filtered. The crude obtained was purified by column chromatography (silica gel, 1% to 3% methanol in chloroform) to obtain the title compound. Yield: 0.11 g, (30.4%); 1H NMR (DMSO-d6, 300 MHz): δ 2.62 (s, 3H, CH3), 3.18 (s, 4H, 2CH2), 3.31 (s, 4H, 2CH2), 3.50 (s, 2H, CH2), 3.85 (s, 3H, OCH3), 5.14 (s, 2H, CH2), 7.04 (s, 1H, Ar), 7.11 (s, 1H, Ar), 7.3-7.32 (m, 5H, Ar), 8.08 (s, 1H, Ar), 8.14 (s, 1H, Ar); MS: m/e (ES+) 528 (M+1); analysis: C27H27ClN2O5S requires C, 61.53,H, 5.16, N, 5.32, Cl, 6.73, S, 6.08; found: C, 61.22, H, 4.99, N, 4.82, Cl, 6.91, S, 6.15%.
