prepared from the reaction of 3H-thiolactams with 1,3-bielectrophiles. These cross-conjugated heteroaromatic betaines undergo regio- and diastereospecific 1,4-dipolar cycloaddition with electron-rich and electron-deficient π-bonds to produce 1,4-cycloadducts containing a carbonyl sulfide bridge. A representative betaine dipole and a 1,4-cycloadduct were characterized by single crystal X-ray determinations
通过3H-
硫代内酰胺与1,3-双亲电子试剂的反应,可以轻松地制备一系列3,3-二取代的双环脱
水4-羟基-2-羟基-2-氧代-
1,3-噻嗪鎓氢氧化物。这些交叉共轭的杂芳族
甜菜碱经过区域和非对映异构的1,4-偶极环加成反应,并带有富电子和缺电子的π键,生成含有羰基硫桥的1,4-环加合物。通过单晶X射线测定来表征代表性的
甜菜碱偶极子和1,4-环加合物。在某些情况下,最初形成的环加合物可以在进一步加热时失去COS。
噻嗪甜菜碱的前沿轨道系数通过PM3哈密顿量的半经验
MOPAC计算确定。1的HOMO