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Thiophene systems. 11 . The synthesis of novel thieno[4,3,2‐ de ] tricyclic ring systems
Author(s) -
Russell Ronald K.,
Rampulla Richard A.,
van Nievelt Caroline E.,
Klaubert Dieter H.
Publication year - 1990
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.5570270647
Subject(s) - chemistry , tricyclic , methanesulfonic acid , ring (chemistry) , alkylation , thiophene , phosphorus pentoxide , hydrolysis , organic chemistry , medicinal chemistry , stereochemistry , catalysis
The synthesis of thieno[4,3,2‐ de ] tricyclic compounds is described. The N ‐1 alkylation of I produced the alkanoic ester precursors. After hydrolysis, the corresponding carboxylic acids were cyclized to the title compounds II . This cyclization step was accomplished with 1:10 phosphorus pentoxide‐methanesulfonic acid. The ketones II were further modified to introduce additional functionality onto this novel tricyclic ring system.