A versatile new synthesis of quinolines and related fused pyridines. Part 7. The conversion of acetamidothiophens into thienopyridines
作者:Otto Meth-Cohn、Brahma Narine、Brian Tarnowski
DOI:10.1039/p19810001531
日期:——
good yield with equimolar amounts of dimethylformamide and phosphoryl chloride in hot dichloroethane. However, undersimilar conditions but with three mol of phosphoryl chloride, 6-chlorothieno[2,3-b]pyridines are obtained. Use of phosphoryl chloride as solvent (7 mol) with three mol of dimethylformamide gives good yields of 6-chlorothieno-[2,3-b]pyridine-5-carbaldehydes. Similarly, thieno[3,2-b]-and thieno[3
将5-取代的2-对乙酰氨基噻吩与等摩尔量的二甲基甲酰胺和磷酰氯在热的二氯乙烷中以良好的产率转化为2-对乙酰氨基噻吩-3-甲醛。然而,在相似的条件下,但是具有三摩尔的磷酰氯,获得了6-氯噻吩并[2,3- b ]吡啶。与三摩尔二甲基甲酰胺一起使用磷酰氯作为溶剂(7摩尔),可以得到6-氯噻吩并-[2,3 - b ]吡啶-5-甲醛的良好收率。类似地,thieno [3,2- b ]-和thieno [3,4- b]-吡啶分别得自3-乙酰氨基噻吩和2,5-二甲基-3-乙酰氨基噻吩。探索了这些反应的机理,并将其与从乙酰苯胺形成相关喹啉中涉及的那些机理进行了比较,并表明它们涉及初始的环甲酰化。显示2-氯喹啉的类似形成具有有限的潜力。