Conversion of 2-Methylthio-4-trifluroacetyl-5,6-dihydro-4H-1,3,4-thiadiazines into α,β-Unsaturated Esters via Carbanion-Induced Ring Opening and Desulfurization
作者:Kazuaki Shimada、Akihiro Otaki、Masaki Yanakawa、Shosuke Mabuchi、Naoya Yamakado、Takeshi Shimoguchi、Yuji Takikawa
DOI:10.1246/cl.1998.329
日期:1998.4
A convenient conversion of 2-methylthio-5,6-dihydro-4H-1,3,4-thiadiazines 1 into α,β-unsaturated esters was achieved through the procedure including trifluoroacetylation of 1, carbanion-induced ring opening of trifluoroacetamides 2, and reductive removal of heteroatom functionality of the resulting S-alkenyl hydrazinecarbodithioates 3. Treatment of 3 with a base under an aqueous condition also gave the corresponding 6-alkylidene-4H-1,3,4-thiadiazin-5-ones 6.
一种方便的方法可以将2-甲基硫代-5,6-二氢-4H-1,3,4-噁二唑啉1转化为α,β-不饱和酯。该过程包括对1进行三氟乙酰化、由碳阴离子诱导的三氟乙酰酰胺2的开环,以及还原去除所得到的S-烯基肼基二硫酸酯3的异原子官能团。将3在水相环境下与碱处理,也得到了相应的6-烷基烯基-4H-1,3,4-噁二唑啉-5-酮6。