以对溴苯甲酸为起始原料,经酰化后生成酰氯,酰氯与N,O-二甲基羟胺盐酸盐反应生成酰胺,再与氯乙烯基镁反应生成α,β不饱和酮。同时,正戊醛与二正丙胺反应生成烯胺。α,β不饱和酮与烯胺经迈克尔加成反应生成分子内醛酮,分子内醛酮经关环反应、乙醇重结晶可得到色谱纯度99.5%以上的反-5-丙基-2-(4’-溴-苯基)-四氢吡喃。 Taking p-bromobenzoic acid as the starting material, the acyl chloride is formed into an acid chloride, the acid chloride is reacted with N, O-dimethylhydroxylamine hydrochloride to form an amide, and then the vinyl chloride is reacted with the vinyl chloride to form the α, β unsaturated ketone. At the same time, n-pentanal and di-n-propylamine react to form enamine. α, β unsaturated ketone and enamine by Michael reaction of the formation of aldehydes and ketones within the molecule, the reaction of aldehydes and ketones through the ring, ethanol recrystallization obtained chromatographic purity of 99.5% of trans-5-propyl-2- ( 4’-bromo-phenyl) -tetrahydropyran.