Synthesis and thermolysis rate constants of diastereomeric oxadiazoline sources of acetoxy(methoxy)carbene — Reaction of acetoxy(methoxy)carbene with isocyanates
作者:Wojciech Sokol、John Warkentin
DOI:10.1139/v06-109
日期:2006.7.1
catalysis were not successful. Thermolysis of the oxadiazolines at 50.4 °C occurred with approximately the same rate constant (ca. 3.6 × 10–5 s–1) to afford acetoxy(methoxy)carbene, which rearranges to methyl pyruvate by acetyl transfer. The carbene, which reacts with relatively unhindered isocyanates to transf...
对甲氧基苯乙酮的甲氧基羰基腙氧化得到顺式和反式-2-乙酰氧基-2-甲氧基-5-(对甲氧基苯基)-5-甲基-Δ3-1,3,4-恶二唑啉(也称为相应的2,5-二氢-1,3,4-恶二唑)以及 1-乙酰氧基-1-(对甲氧基苯基乙基)二氮烯羧酸甲酯。三种异构体通过光谱方法分离和鉴定。1-乙酰氧基-1-(对甲氧基苯基乙基)二氮烯羧酸甲酯是二氯甲烷中氧化的主要产物。在乙酸中氧化没有得到恶二唑啉,但得到二氮烯羧酸盐和另外的 1-(对甲氧基苯基)乙酸乙酯。通过酸催化将二氮烯羧酸异构化为恶二唑啉的尝试没有成功。恶二唑啉在 50.4 °C 下发生热解,速率常数大致相同(约 3. 6 × 10–5 s–1) 得到乙酰氧基(甲氧基)卡宾,其通过乙酰基转移重排为丙酮酸甲酯。卡宾与相对不受阻碍的异氰酸酯反应以转移...