中间体3-甲酰四氢噻喃的合成

3-甲酰四氢噻喃是噻草酮的重要中间体，3-甲酰四氢噻喃的合成采用以丙烯醛和硫化氢为原料首先得到3-甲酰-5，6-二氢噻喃，然后3-甲酰-5，6-二氢噻喃在催化荆作用下氢化得到目标产物的合成路线．合成3-甲酰-5，6～二氢噻喃中，对丙烯醛投料方式、硫化氢投入量和催化剂选择进行了优化试验，提出了新的反应机理，使3-甲酰-5，6-二氢噻喃反应收率和质量分数分别达到93％和95％以上．制备3-甲酰四氢噻喃中，对催化剂进行了选择试验，发现用Raney-Ni作催化剂，目标产物的质量分数和收率达到92％和94％以上．

Synthesis of 3-formyltetrahydrothiopyran

3-Formyltetrahydrothiopyran is an intermediate of Cycloxydirn. 3-Formyltetrahydrothiopyran was pre- pared by hydrogenating a 3-forrnyl-5,6-dihydro-2H-thiopyran in the presence of a catalyst and 3-frornyl-5,6-dihydro- 2H-thiopyran was prepared by reacting an acrolein with hydrogen sulfide. Under the optimal conditions of feeding method of arcolein, amount of hydrogen sulfide, and catalyst selection, the yield and purity of 3-forrnyl-5,6-dihydro- 2H-thiopyran was more than 93% and 95%, respectively. A new reaction mechanism was proposed. Based on the optimized test of catalyst. 3-Formyltetrahydrothiopyran had a yield above 94% and product content above 92% by using Raney-Ni as catalyst.