微波促进的取代酚类化合物的邻甲酰化反应研究

Research on Microwave Accelerated Ortho-formylation Reactions of Substituted Phenols

以4-氯苯酚(1a)为原料,研究了微波促进的取代酚类化合物的邻甲酰化反应。考察了催化剂种类及其用量、溶剂、1a与多聚甲醛摩尔比(r)、微波辐射功率和辐射时间等对反应的影响。结果表明:以THF为溶剂,MgCl2/Et3N(2. 5 eq.)为催化剂,r=1/5,在400 W微波功率下辐射反应5 min,5-氯-2-羟基苯甲醛(2a)的产率为85%,其结构经1H NMR确证。该反应条件还适用于多种取代酚(1b～1f)的邻甲酰化反应,产率为78%～90%。

Microwave accelerated o-formylation reactions of substituted phenols was discussed by using4-chloro phenol(1a)as the material.Effects of catalysts type and amount,solvents,molar ratio(r)of1a and paraformaldehyde,reaction time and the power of microwave radiation on the reaction were investigated.The experimental results indicated that MgCl2/Et3N(2.5eq.)as catalyst,r=1/5,THF as solvent,microwave radiation at400W for5min,the yield of5-chloro-2-hydroxybenzaldehyde(2a)was85%.The structure was confirmed by^1H NMR.Besides,this reaction conditions also suited to ortho-formylation of other phenols(1b^1f)and showed a remarkable tolerance toward different functional groups.The yields were78%~90%.