Glyconothio-<i>O</i>-lactones. Part III. Thermolysis of a 4,5-Dihydro-1,2,3- and a 2,5-Dihydro-1,3,4-thiadiazole
作者:Bruno Bernet、Thomas Mäder、Andrea Vasella
DOI:10.1002/hlca.19970800422
日期:1997.6.30
HPLC of the thermolysis product of 2 gave the enethiol 17, the sulfide 19, and the mercapto alcohol 18 as secondary products. Thermolysis of the thiirane 9 at 110–120° (Scheme 4) led to the anomeric thiirane 12 which was transformed into mixtures of the enethiol 17 and the enol ether 7. Addition of H2O to 17 and 7 gave the corresponding hemiacetals 18 and 20. The mechanism of the thermolysis of the dihydrothiadiazoles
将CH 2 N 2加到2,3:5,6-二-O-异亚丙基-1-硫代甘露糖醇-1,4-内酯(1)中,得到2,5-二氢-1,3,4-噻二唑2和4,5-二氢-1,2,3-噻二唑3。第一阶观察动力学的热解3(方案3)在80-110°用C 6 d 5 Cl溶液和第2(方案3中CDC1)在20-35° 3,分别。1,2,3-噻二唑3导致了硫杂丙环的混合物9中,起始thionolactone 1中,硫羰-1,5-内酯8和烯醇醚7,而异构体1,3,4-噻二唑2则生成异头噻烷9和12的混合物,O氢S,O,O-邻内酯α-D- 14,S-甲基硫酯15,S,S,O-正内酯13和2,3:5,6-二-O异亚丙基-甘露糖-1,4-内酯(16)。通过半制备超临界流体色谱(SFC)分离出热分解的纯产物,而制备HPLC则导致部分或完全分解。因此,通过制备型HPLC分离了3的粗产物,在115–120°下被未知S物质污染的β-D-