Synthesis of five-membered heterocycles containing a nitrogen-oxygen bond via O-acylation of aliphatic nitro compounds.
作者:KAZUHO HARADA、EISUKE KAJI、SHONOSUKE ZEN
DOI:10.1248/cpb.28.3296
日期:——
O-Acylation of primary aliphatic nitro compounds with acid chlorides in N, N-dimethylacetamide led to the formation of nitrile oxides, which cyclized in situ with olefinic dipolarophiles in a 1, 3-dipolar cycloaddition mode to afford 2-isoxazoline derivatives. Optimum reaction conditions were investigated, and the use of several types of dipolarophiles, such as acetylenes, Schiff bases, aromatic nitriles, and ketones, in this cycloaddition resulted in the formation of the corresponding cycloadducts, namely isoxazoles, 1, 2, 4-oxadiazolines, 1, 2, 4-oxadiazoles, and 1, 4, 2-dioxazoles, respectively, in reasonable yields.
初级脂肪族硝基化合物与酸氯化物在N,N-二甲基乙酰胺中进行O-酰化反应,形成了腈氧化物,这些腈氧化物与烯烃类双极试剂在1,3-双极环加成模式下原位环化,生成了2-异噁唑啉衍生物。研究了最佳反应条件,使用多种类型的双极试剂,如炔烃、施夫碱、芳香族腈和酮类,进行这一环加成反应,分别合理产率地生成了相应的环加成产物,即异噁唑、1,2,4-噁二唑啉、1,2,4-噁二唑以及1,4,2-二噁唑。