Mechanism of thiazolidine hydrolysis. Ring opening and hydrolysis of 1,3-thiazolidine derivatives of p-(dimethylamino)cinnamaldehyde
作者:Thomas H. Fife、R. Natarajan、C. C. Shen、Ramesh Bembi
DOI:10.1021/ja00008a041
日期:1991.4
be monitored at pH 3-10. Ring opening involves a pH-independent reaction at pH>4, which proceeds 2.25-fold slower in D 2 O than in H 2 O, and hydronium ion catalysis at low pH. General acid catalysis in ring opening was observed with acetic acid buffers. Ring opening of the N-butylthiazolidine occurs 250-fold more rapidly than with the N-phenyl derivative. The plot of log k 0 vs pH for aldehyde formation
2-(对-(二甲氨基)苯乙烯基)-1,3-噻唑烷和相应的N-丁基和N-苯基衍生物在pH 1-12范围内的水解反应通过在平衡环中形成的亚胺离子中间体进行-开反应。用分光光度法检测这种中间体(λ max = 480-525 nm)。可以在 pH 3-10 下监测 N-苯基-1,3-噻唑烷开环中亚胺离子的快速形成。开环涉及在 pH>4 时不依赖于 pH 的反应,该反应在 D 2 O 中的进行速度比在 H 2 O 中慢 2.25 倍,并且在低 pH 下进行水合氢离子催化。用乙酸缓冲液观察到开环中的一般酸催化作用。N-丁基噻唑烷的开环速度比 N-苯基衍生物的开环速度快 250 倍。