以(S)-脯氨酸1为原料,在酸性条件和金属锌的催化还原作用下,通过与甲醛反应,高收率获得了(S)-N-甲基脯氨酸2。然后在N,N-二甲基乙酰胺(DMAc)和CH_2Cl_2体系中,(S)-N-甲基脯氨酸2与SOCl_2在0℃下反应20min,制得的酰氯不经提纯直接与加入的甲醇在25℃下反应5h,获得中间产物(S)-N-甲基脯氨酸甲酯3。最后以LiAlH_4为还原剂,四氢呋喃为溶剂,高收率(87.3%)地获得了(S)-N-甲基脯氨醇4。产物结构经~1 H NMR、^(13)C NMR、HRMS确证。
Wells-dawson type heteropolyacid catalyst was prepared by acidification-etherization and characterized by FTIR,over which cyclohexanone ethylene ketal was synthesized from cyclohexanone to ethylene.The experiment results showed that the optimal reaction conditions are as follows:the amount of Cyclohexanone is 0.1mol,the molar ratio of Cyclohexanone to ethylene was1.0/1.5(mol/mol),catalyst amount 1.50%(pencent of the reaction stock materials).Through reaction time 2.5h,the yield of cyclohexanone ethylene katal reached over 95.0%.
