Beckmann Fragmentation and Rearrangement. Part VII. Fragmentation and cyclization of ?-methylthio-ketoximes. Fragmentation reactions no. 27
作者:Cyril A. Grob、Junya Ide
DOI:10.1002/hlca.19740570833
日期:——
however, undergoes a Beckmann rearrangement. The fragmentation of α-methylthio-isobutyropher one anti-oxime tosylate (13b) is accompanied by cyclization to the 1, 2-thiazetin-1-ium ion 27, which is hydrolyzed via the sulfimine 29 to the keto sulfide 20 and the keto sulfoxide 30. A comparison of the rates of the α-alkylthio anti-ketoxime tosylates 12b and 13b and of the homomorphous oxime tosylates 16b and
α-甲硫基丙酮抗肟对甲苯磺酸酯(甲苯磺酸盐)(12b)片段在80%乙醇中定量产生苄腈和亚甲基ide离子15。的顺式异构体,然而,经历贝克曼重排。α-甲硫基异丁环酮一种抗肟甲苯磺酸酯(13b)的断裂伴随环化成1,2-噻嗪-1-鎓离子27,后者通过亚氨基29水解为酮硫醚20和酮亚砜。30日。α-烷硫基抗酮肟甲苯磺酸酯12b和13b与同型肟甲苯磺酸酯16b和17b的速率的比较表明,硫原子强烈地促进了片段化和环化。而既抗-and顺式α氨基酮肟衍生物的异构体定量片段,只有抗α -烷硫基酮肟衍生物的异构体经历容易碎裂。