Abstract: Thermal cyclization of dehydrolinalool with 97.2 mass percent at 198—202 ℃ under the condition of atmospheric pressure for 7.5h gave the product containing of 94.0 mass percent of cis and trans isomers of 1-methyl-2-methylidene-3-isopropenyl-1-cyclopentanol which were characterized by GC-MS，GC-IR，¹³C NMR，HSQC and ¹H NMR spectroscopy. Effect of temperature on the thermal cyclization of dehydrolinalool was investigated. Based on the analytical data of the sample of 1-methyl-2- methylidene-3-isopropenyl-1-cyclopentanol prepared as above and impurities tested by GC/MS spectra in dehydrolinalool，it showed that the primary impurities formed in the rectification process of dehydrolinalool under vacuum condition are cis and trans isomers of 1-methyl-2-methylidene-3- isopropenyl-1-cyclopentanol.

Key words: thermal cyclization, dehydrolinalool, NMR spectroscopy, cis and trans-1-methyl-2- methylidene-3-isopropenyl-1-cyclopentanol, structure characterization of impurity

摘要： 以质量分数为97.2%的脱氢芳樟醇为原料，198～202 ℃、常压条件下进行热环化反应，反应时间7.5 h，得到质量分数为94.0%的1-甲基-2-亚甲基-3-异丙烯基-1-环戊醇顺反异构体混合物，以GC/IR、GC/MS、¹H NMR、¹³C NMR、HSQC技术对自制的1-甲基-2-亚甲基-3-异丙烯基-1-环戊醇样品进行表征。考察了温度对脱氢芳樟醇热环化反应影响，以自制1-甲基-2-亚甲基-3-异丙烯基-1-环戊醇标样进行比对分析，结合脱氢芳樟醇精馏产品杂质的GC/MS谱图，确定脱氢芳樟醇减压精馏过程形成的主要杂质是1-甲基-2-亚甲基-3-异丙烯基-1-环戊醇顺反异构体混合物，是由脱氢芳樟醇精馏过程中发生热环化反应形成的。

关键词: 脱氢芳樟醇, 热环化反应, 1-甲基-2-亚甲基-3-异丙烯基-1-环戊醇, NMR分析, 杂质结构表征, thermal cyclization , dehydrolinalool , NMR spectroscopy, cis and trans-1-methyl-2-methylidene-3-isopropenyl-1-cyclopentanol , Structure characterization of impurity, 脱氢芳樟醇, 热环化反应, 1-甲基-2-亚甲基-3-异丙烯基-1-环戊醇, NMR分析, 结构表征