3-Aryl-3-hydroxy-1-methylazetidine-2-thiones react with HCl in DMSO to give 3-methyl-5-aryloxazole-2-thiones. Substituent effects correlate with rate effects on hydrolyses of acetals of benzaldehyde. An (17)O labeling experiment indicates that the oxygen atom of the product is derived from the hydroxyl group. Trifluoroacetic anhydride/DMSO in CH2Cl2 can also promote the reaction. Mechanisms involving
3-芳基-3-羟基-1-甲基氮杂
环丁烷-2-
硫酮与HCl在
DMSO中反应,生成3-甲基-5-芳基
恶唑-2-
硫酮。取代基作用与速率对
苯甲醛缩醛水解的作用有关。(17)O标记实验表明产物的氧原子衍生自羟基。
CH2Cl2中的
三氟乙酸酐/
DMSO也可以促进反应。涉及激活基质的Grob型断裂,然后进行环化或环丙基羰基型重排的机制可以解释这种氧化性重排。