Polyketoenols and chelates. The mechanism by which glaucophanic enols are formed
作者:S. Richard Baker、Leslie Crombie
DOI:10.1039/p19810000172
日期:——
dimethyl glaucophanic enol (4) by coupling the anion from 3-acetyl-5-methoxycarbonyl-6-methyl-2-pyrone (2)(2 mol equiv.) through a one-carbon source were unsuccessful, as were attempts to derive it by treating the anion with dimethyl xanthophanic enol (5). However, a ‘melt reaction’ between pyrone (2)(2 mol equiv.), methyl methoxymethyleneacetoacetate (1 mol equiv.), and dry sodium methoxide gave glaucyrone
尝试通过单碳源将3-乙酰基-5-甲氧基羰基-6-甲基-2-吡喃酮(2)(2摩尔当量)的阴离子偶合来制备二甲基青庚烯型烯醇(4)的尝试没有成功。通过用二甲基黄体烯醇(5)处理阴离子来衍生。但是,在吡喃酮(2)(2摩尔当量),甲氧基亚甲基乙酰乙酸甲酯(1摩尔当量)和干燥的甲醇钠之间进行“熔融反应”,得到了青草酮(4)(49%)。通过使用甲氧基甲基[ 14反应中获得的C]亚甲基乙酰乙酸酯标记的青草酮(4)和x吨酮(5)具有相同的比活。(4)中标记的中心(C-8)位置由甲醇镁催化转化为查尔酮(7)转化为查尔酮(7),并被臭氧化为(8)和(9)。通过Dakin反应从(4)中的C-8中提取对应于C-8的原子占原始放射性的89%。两个残留的芳族片段各自包含4%的活性,这可以通过将标记平衡到(4)的吡喃环中来解释。现在可以促进在“熔解反应”中形成黄嘌呤酮和青草酮的统一机制,并且可以理解有利于一种或另一种产物的因素。