Reactions of 2-aminooxazoles and 2-aminothiazoles with dienophiles. Isolation of stable diels-alder adducts
作者:George Crank、Humaid R. Khan
DOI:10.1002/jhet.5570220527
日期:1985.9
Room temperature reaction of 2-aminooxazole 1 and its 4- and 4,5-substituted derivatives, with dimethyl acetylenedicarboxylate gave good yields of Diels-Alder adducts 2, isolated as stable crystalline compounds. A competing process produced oxazole[3,2-a]pyrimidines 3, also in good yield. Minor products were also identified. 2-Amino-4-methylthiazole (6) reacted in a similar manner and gave the Diels-Alder
2-氨基恶唑1及其4-和4,5-取代的衍生物与乙炔二羧酸二甲酯的室温反应产生了良好的狄尔斯-阿尔德加合物2的收率,以稳定的结晶化合物的形式分离。竞争性方法生产的恶唑[3,2- a ]嘧啶3的收率也很高。还确定了次要产品。2-氨基-4-甲基噻唑(6)以相似的方式反应,得到狄尔斯-阿尔德加合物7和噻唑[ 3,2- a ]嘧啶8作为主要产物,噻唑[3, 2- d ] [1:3]二氮杂((9)。氨基恶唑与烯属亲二烯体反应生成吡啶衍生物,该吡啶衍生物是通过破坏原始的不稳定加合物而形成的。