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Synthesis of tetracyclic system of 2,4‐di( tert ‐butyl)‐6,7‐dihydrofuro[2′,3′:3,4]cyclohepta[1,2‐ b ]indole
Author(s) -
Butin Alexander V.,
Kostyukova Olga N.,
Tsiunchik Fatima A.,
Uchuskin Maxim G.,
Serdyuk Olga V.,
Trushkov Igor V.
Publication year - 2011
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.635
Subject(s) - chemistry , furan , benzene , indole test , ring (chemistry) , medicinal chemistry , stereochemistry , organic chemistry
For the first time, tetracyclic compounds, namely, furo[2′,3′:3,4]cyclohepta[1,2‐b]indoles were synthesized by recyclization of ortho ‐substituted aryldifurylmethanes containing tert ‐butyl groups at C5 positions of the furan rings. It was shown that [2‐(benzoylamino)phenyl]bis(5‐ tert ‐butyl‐2‐furyl)methanes 12 are transformed into tetracycles 15 at room temperature under treatment with POCl 3 in benzene solution containing some drops of water. The reaction proceeds via the intermediate formation of 1‐benzoylamino‐3‐(5‐ tert ‐butyl‐2‐furyl)‐2‐(4,4‐dimethyl‐3‐oxopentyl)indoles 14 which can be isolated from the reaction mixture. The method is very simple but its application is restricted due to side reactions if electron‐releasing groups are present in 12 . On the other hand, the decrease of electron density on furan ring in the starting compounds (for example, the use of [2‐X‐phenyl]difurylmethanes (where X = tosylamino or hydroxy group) prevents cyclization under the studied reaction conditions. As a result, corresponding ketones are formed as products of recyclization. J. Heterocyclic Chem., (2011).