Hydrochloric Acid → 7-nitro-6-(4-o-tolyl-piperazin-1-yl)-2H-isoquinolin-1-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-methyl-5-nitro-4-(4-o-tolyl-piperazin-1-yl)-benzamide (3.0 g, 8.46 mmol) and dimethylformamide dimethyl acetal (1.32 g, 11.08 mmol) in 2-methyl tetrahydrofuran (60 mL) were heated in a Dean stark apparatus at 105° C. for 30 min. The progress of the reaction was monitored by LCMS. The volume of the reaction was reduced to half and the reaction mass was cooled to 55° C. A solution of potassium tert-butoxide (1.44 g, 12.8 mL, 12.86 mmol) in THF (1 M) was added dropwise over a period of 30 min. The reaction mixture was allowed to heat at 65° C. overnight. After completion of the reaction, solvent was removed in vacuo, residue obtained was acidified with 1.5 N HCl. The aqueous layer was extracted in dichloromethane (5×75 mL). The combined extract was washed with water, brine solution and dried over anhydrous Na2SO4. The crude product obtained was purified by the flash column chromatography (230-400 size mesh) using 1.0-1.25% methanol in dichloromethane to afford the compound 7-nitro-6-(4-o-tolyl-piperazin-1-yl)-2H-isoquinolin-1-one. Yield (0.25 g, 8.3%; and reddish brown solid).

Provenance & Evidence