Haloacetylated enol ethers. 7 . Synthesis of 3-aryl-5-trihalomethylisoxazoles and 3-aryl-5-hydroxy-5-trihalomethyl-4,5-dihydroisoxazoles
作者:Marcos A. P. Martins、Geonir M. Siqueira、Giovani P. Bastos、Helio G. Bonacorso、Nilo Zanatta
DOI:10.1002/jhet.5570330612
日期:1996.11
cyclocondensed with hydroxylamine hydrochloride to afford the 3-aryl-5-hydroxy-5-trihalomethyl-4,5-dihydroisoxazoles 3a-g, 4a-f in good yield. The dehydratation of compounds 3a-g with concentrated sulfuric acid, led the corresponding 3-aryl-5-trichloromethylisoxazoles 5a-g. An alternative one-pot procedure yields 3-aryl-5-trihalomethylisoxazoles 5,6a-g directly by cyclocondesation of 1,2a-g with hydroxylamine
β-芳基-β-甲氧基乙烯基三卤甲基酮1a-g,2a-g [芳基= p -YC 6 H 4,其中Y = H,Me,OMe,F,Cl,Br,NO 2 ]与羟胺盐酸盐环缩合得到3-芳基-5-羟基-5-三卤甲基-4,5-二氢异恶唑3a-g,4a-f具有良好的收率。用浓硫酸使化合物3a-g脱水,得到相应的3-芳基-5-三氯甲基异恶唑5a-g。另一种一锅法直接通过1,2a-g的环缩构反应生成3-芳基-5-三卤代甲基异恶唑5,6a -g 在过量浓盐酸存在下,用盐酸羟胺处理。