Dihalogentriphenylphosphorane in der Heterocyclensynthese, 29.<sup>1</sup>Eine einfache Synthese von Pteridin-4-onen aus 3-Amino-2-pyrazincarbonsäuremethylester und Pyrazino[3,1]oxazin-4-onen
作者:Heinrich Wamhoff、Elmar Kroth
DOI:10.1055/s-1994-25487
日期:——
Dihalogentriphenylphosphoranes in the Synthesis of Heterocycles, 29.1 A Simple Synthesis of Pteridin-4-ones, from Methyl 3-Amino-2-pyrazinecarboxylate and Pyrazino[3,1]oxazin-4-ones Methyl 3-amino-2-pyrazinecarboxylate(3) affords the synthetically useful 3-aroylaminopyrazin-2-carboxylates 5a-f with aroyl chlorides, which are converted with dibromotriphenylphosphorane into 2-arylpyrazino[2,3-d][3,1]oxazin-4-ones 6a-f. Nucleophilic attack at the carbonyl function of these oxazinones results in ring cleaved amides which can be recyclized with dibromotriphenylphosphorane to afford 2-arylpteridin-4-ones 7a-f.
对苯基膦盐在杂环合成中的应用,29.1 简单合成4-氮杂嘧啶酮,从甲基3-氨基-2-吡嗪羧酸酯和吡嗪[3,1]噁嗪-4-酮。甲基3-氨基-2-吡嗪羧酸酯(3)与酰氯反应生成合成上有用的3-酰氨基吡嗪-2-羧酸酯5a-f,随后与二溴三苯基膦反应,生成2-芳基吡嗪[2,3-d][3,1]噁嗪-4-酮6a-f。对这些噁嗪酮的羰基官能团进行亲核攻击,产生开环的酰胺,这些酰胺可以与二溴三苯基膦再循环,生成2-芳基4-氮杂嘧啶酮7a-f。