Synthesis of symmetrical 2,2′,4,4′-tetrasubstituted[4,4′-bioxazole]-5,5′(4<i>H</i>,4′<i>H</i>)-diones and their reactions with some nucleophiles
作者:Kenneth K. Andersen、Daniel F. Gloster、Diana D. Bray、Massud Shoja、Anders Kjaer
DOI:10.1002/jhet.5570350210
日期:1998.3
Several symmetrical 2,2′,4,4′-tetrasubstituted[4,4′-bioxazole]-5,5′(4H,4′H)-diones 1a-f were obtained by dehydrodimerization of 5(4H)-oxazolones 2a-f. The configurations of four were established; one by X-ray crystallography rac-1c, and three rac-1a, meso-1a and rac-1b by 1H nmr spectroscopy of their derivatives. Upon being heated, the bioxazolones isomerized, presumably by breakage of the 4,4′-carboncarbon
几个对称2,2',4,4'-四取代[4,4'- bioxazole] -5,5-'(4 ħ,4' ħ) -二酮1A-F 5(4 dehydrodimerization获得ħ) -恶唑酮2a-f。建立了四个的配置。1个通过X射线晶体学rac - 1c进行分析,三个rac - 1a,meso - 1a和rac - 1b通过1 H nmr光谱对其衍生物进行分析。加热后,生物恶唑酮被异构化,可能是由于4,4'-碳的断裂碳键形成自由基,然后重组。交叉实验的结果与该异构化反应的自由基性质一致。用甲醇和胺亲核试剂处理三种生物恶唑酮rac - 1a,meso - 1a和rac - 1c,可得到α,α'-脱氢二聚氨基酸的酯和酰胺衍生物7-11。