唑的合成研究

Synthesis of oxazole

以对甲苯磺酰甲基异氰(化合物2)和多聚甲醛为原料,在碱性条件下反应得到4-甲苯磺酰基-4,5-二氢唑(化合物3),化合物3再经强碱性脱除对甲苯磺酰基得到唑(化合物1),产物及中间体结构经1 HNMR和MS确证。确定的化合物3的最佳反应条件为:n(多聚甲醛)∶n(化合物2)=1.05∶1,反应溶剂为二甲基亚砜,n(K2CO3)∶n(化合物2)=1.1∶1,反应时间为5h。在此最佳工艺条件下,化合物3的收率为84.8%。

Oxazole was synthesized from TOSMIC and paraformaldehyde through a two-step reaction.Firstly,4-tosyl-45-dihydrooxazole(3)was obtained in basic condition,then oxazole(1)was obtained by TOS group removed also in basic condition.The structure of the product and intermediate were confirmed by 1 HNMR and MS.The effect of reaction conditions on the yield of compound 3 were investigated,the optimal conditions were as follows:the mole ratio of n(paraformaldehyde)∶n(compound 2)=1.05∶1,the solvent is DMSO,the amount of K2 CO3 is n(K2 CO3)∶n(compound 2)=1.1∶1,the reaction was at room temperature for 5 h.Compound 3 was obtained in the yield of 84.8%by optimal reaction conditions.