Electrophilic substitution in indoles. Part 18. Cyclisation of N-acyltryptamines
作者:Kshetra M. Biswas、Anthony H. Jackson、Mozaina M. Kobaisy、Patrick V. R. Shannon
DOI:10.1039/p19920000461
日期:——
Cyclisation of Nb-acetyltryptamines 8 with trifluoroacetic anhydride, or pentafluoropropionic anhydride, affords spirocyclic indolines of types 14 and 15 in virtually quantitative yields. The mechanism of the reactions involves Cyclisation by ipso-attack at the 3-position of the indole nucleus, to form spirocyclic 3H-indoles 12 and 13, which subsequently undergo addition of the anhydride to the 1,2-double
用三氟乙酸酐或五氟丙酸酐将N b-乙酰色胺8环化,可得到几乎定量的14和15型螺环二氢吲哚。反应的机制涉及通过环化本位在吲哚核的3-位-attack,以形成螺环3 ħ -indoles 12和13,其随后经历添加酸酐与的3 1,2-双键H-吲哚。通过转化3 H-吲哚-3-螺环戊烷16已确定了后者反应的一般性。和亚苄基苯胺18分别加入到酸酐加合物17a和19中。螺环二氢吲哚加合物14a,14b,15a,15b和17a被稀氨水迅速水解成羟基螺环二氢吲哚20a,20b,21a,21b和17b。