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d-生物素的不对称全合成研究(Ⅱ) 总被引:2,自引:0,他引:2
1,3-二苄基咪唑啉-2-酮-顺-4,5-二羟酸经脱水、单酯化,折分成分(4S,5R)-顺1,3-二苄基-5-甲氧基羧基-2-氧代咪唑啉-4-羧酸,再经还原环合,硫代成(3aS,6aR)-1,3-二苄基-四氢-4H-噻吩并[3,4-d)咪唑-2,4(1H)-二酮(7),后者经格氏反应、脱水、还原、裂解环合一锅合成(3aR,8aS,8bS)-1,3-二苄基-2-氧代十氢咪唑[3,4-d]噻吩并[1,2-a]锍翁溴化物(11),继而经缩合、开环、水解、脱羧、脱苄而得d-生物素(1),总收率为14.5%。 相似文献
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In the condensation of arylaldehydes with arylethylidenemalononitriles, it was found that, besides the normal product dienes a, the ring-closure product quinoline derivatives b can be also obtained in 26%--50% yields. The substituent effects were also examined and a possible reaction mechanism was proposed for the formation of b. The X-ray crystal structure of lb confirms the structure of the ring-closure product. 相似文献
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