反应详情

Following the general procedure described above for the synthesis of 11-(4-nitrophenyl)-4-(pentan-3-yl)piperazine, treatment of 1-(4-nitrophenyl)piperazine (5.00 g, 24.1 mmol, 1.0 equiv.) with cyclohexanone (7.10 g, 72.4 mmol, 2.0 eq) in DCM (100 mL) at rt for 72 h provided the title compound as a yellow solid (4.80 g, 68% recovery, 89% purity as determined by LC/MS analysis @ UV 254 nm detection). In this case, an additional portion (25 mL) is added to the reaction mixture after 1 h. Upon addition of hexane (25 mL) to the crude residue, obtained from evaporation of the DCM extract, and stirring for 24 h the product precipitated from solution and was collected by filtration, washed with hexanes (2×25 mL), and dried under vacuum. The crude product is used in the next step without further purification. LCMS purity: 89% by UV 254 nm detection. LCMS-ESI (m/z): calcd for C16H23N3O2, 289; [M+H]+ found, 290.