Investigation of the Enzymatic and Nonenzymatic Cope Rearrangement of Carbaprephenate to Carbachorismate
作者:Andreas Aemissegger、Bernhard Jaun、Donald Hilvert
DOI:10.1021/jo026096s
日期:2002.9.1
carbachorismate is also observed by NMR as a minor product. Carbaprephenate is not a substrate for the enzyme chorismate mutase from Bacillus subtilis (BsCM), nor does carbaprephenate inhibit the normal chorismate mutase activity of this enzyme, even when present in 200-fold excess over chorismate. Its low affinity for the enzyme-active site is presumably a consequence of placing a methylene group rather
氨基丁酸酯和4-表-氨基甲酸酯的二甲酯是通过修改已公开的程序制备的。在甲醇中,这些化合物通过涉及初始Cope重排的两步顺序,然后通过分子内Diels定量转化为6-羟基三环[3.3.1.0(2,7)] non-3-en-1,3-二甲基酯异构体-二甲氨基甲酸酯或4-表甲氨基甲酸酯中间体的醛反应。氨基甲酸酯及其差向异构体通过碱水解相应的二甲基酯获得。与它们的酯前体相反,这些化合物在水溶液中经历自发的酸催化的脱羧。仅在高pH下,Cope重排才与脱羧反应竞争。在pH值为12和90摄氏度时,氨基甲酸酯会缓慢重排为氨基甲酸酯,迅速失去水分,以3-(2-羧基烯丙基)苯甲酸为主要产物。NMR还观察到少量的衍生自羧甲酸酯的分子内Diels-Alder加合物,为次要产物。氨基甲酸酯不是枯草芽孢杆菌(BsCM)的分支酸突变酶的底物,即使存在超过分支酸200倍的氨基甲酸酯也不能抑制该酶的正常分支酸突变酶活性。它对酶