作者:Alfred Hassner、Larry R. Krepski、Vazken Alexanian
DOI:10.1016/0040-4020(78)89005-x
日期:1978.1
4-substituted pyridines were found to be acylation catalysts, the most effective being 4-pyrrolidinopyridine 4 and 1,1,3,3-tetramethyl-4-(4-pyridyl)guanidine 8. The reaction of t-butanol with an isocyanate is also accelerated by the presence of 4 but not as much as in the case of acylations. The cause of the pronounced effect of these pyridine species in catalyzing acylation reactions seems to be a
通过添加催化量(0.02-0.1当量)的4-二烷基氨基吡啶,可大大促进未反应性醇与酸酐的酰化反应。在非极性反应中,该反应比在极性溶剂中的反应快,并且乙酰氯不如乙酸酐有效。已经研究了几种吡啶,哒嗪和喹啉衍生物作为潜在的酰化催化剂。在所考察的系统中,仅发现少数4-取代的吡啶是酰化催化剂,最有效的是4-吡咯烷二吡啶吡啶4和1,1,3,3-四甲基-4-(4-吡啶基)胍8。4的存在也会促进叔丁醇与异氰酸酯的反应但不如酰化作用那么大。这些吡啶物质在催化酰化反应中显着作用的原因似乎是4-取代基供体能力增强和该取代基对酰基吡啶鎓中间体具有稳定作用的结合。