1,5-Hydride shift in products of Stevens 3,2-rearrangement of methyl(alkyl)(alkoxycarbonylmethyl)-(3-phenyl-2- propynyl)ammonium bromides
作者:V. S. Ovsepyan、A. V. Babakhanyan、M. O. Manukyan、S. T. Kocharyan
DOI:10.1007/s11176-005-0014-7
日期:2004.9
The products of the Stevens 3,2-rearrangement of ammonium salts containing methyl and other (ethyl, propyl, butyl) alkyl groups along with 3-phenylprop-2-ynyl, under the reaction conditions undergo, roughly by half, intramolecular hydride shift with intermediate formation of immonium salts. The latter convert into enamino esters whose hydrolysis involving alkyl groups at the nitrogen atom gives rise to lower aliphatic aldehydes and the corresponding amino esters. Treatment with dilute hydrochloric acid of the reaction mixture containing enamino esters results in formation of hydrogenated and nonhydrogenated alkyl esters of α-keto acids. This mixture was reacted with concentrated hydrochloric acid to obtain 3-hydroxy-5-methyl-4-phenylfuran-2(5H)-one from the nonhydrogenated keto ester and to isolate pure the hydrogenated keto ester.
含有甲基和其他(乙基、丙基、丁基)烷基以及 3-苯基丙-2-炔基的铵盐在斯蒂文斯 3,2 重排反应中的产物,在反应条件下大致会发生一半的分子内氢化物转移,中间形成亚铵盐。后者转化为烯丙基氨基酯,其水解涉及氮原子上的烷基,生成低级脂肪醛和相应的氨基酯。用稀盐酸处理含有烯氨基酯的反应混合物,可生成氢化和非氢化的 α-酮酸烷基酯。该混合物与浓盐酸反应,从非氢化酮酯中得到 3-羟基-5-甲基-4-苯基呋喃-2(5H)-酮,并分离出纯净的氢化酮酯。