An approach to canthine derivatives using the intramolecular Pictet-Spengler condensation
作者:Jan H van Maarseveen、Suzanne J.E Mulders、RenéW.M Aben、Chris G Kruse、Hans W Scheeren
DOI:10.1016/0040-4020(95)00169-9
日期:1995.4
mild conditions. With Na-propanal chains, only dimeric and oligomeric compounds were isolated. With the Na-pentanal chain (unidentified) oligomeric compounds were formed as well. The monomeric canthine-like products have not been detected in these cases, probably because formation has to proceed via conformationally disfavored intermediate cyclic iminium ions. Cyclization of Na-butanal functionalized Nb-formyl-
所述canthine衍生物1b中通过处理N个有效地合成一个(4,4-二乙氧基丁基)-N - b -allyloxytryptamine 9B用TFA / H 2 ö氯仿。该结果表明,在温和条件下,通过中间亚胺离子上吲哚2-位的直接攻击确实可以发生PS环化。用N-一-丙醛链,只有二聚和低聚化合物中分离得到。与N一还形成了-戊醛链(未鉴定的)低聚化合物。在这些情况下,未检测到单体类鸟氨酸产物,可能是因为形成必须通过构象不利的中间环亚胺离子进行。N个环化一-丁醛官能化的N- b甲酰基或N b -benzyltryptamines图9c和9d中,这是已知的速率在PS缩合增强取代基,意外地得到3,4-二氢嘧啶并[1,2一]吲哚16C ,d高产。产物16c,d是通过质子化醛在吲哚2-位上的直接亲电进攻而形成的。