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Furan ring opening ‐ indole ring closure: Synthesis of furo[2′,3′:3,4]‐cyclohepta[1,2‐ b ]indolium chlorides
Author(s) -
Butin Alexander V.,
Smirnov Sergey K.,
Stroganova Tatyana A.
Publication year - 2006
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570430315
Subject(s) - chemistry , furan , ring (chemistry) , disproportionation , indole test , intramolecular force , closure (psychology) , medicinal chemistry , pyrrole , stereochemistry , organic chemistry , catalysis , law , political science
A new synthetic approach to furo[2′,3′:3,4]cyclohepta[1,2‐ b ]indolium chlorides is elaborated starting from 2‐acetylaminoaryldifurylmethanes or 2‐aminoaryldifurylmethanes under treatment with methanolic HCl solution. The reaction proceeds in three steps: recyclization, intramolecular cyclization, and disproportionation. In this case the furan ring takes part in building up both pyrrole and seven‐membered rings. The same salts can be obtained directly from 2‐acetylaminobenzaldehydes and 2‐methylfuran under similar conditions without isolation of corresponding 2‐acetylaminoaryldifurylmethanes.