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Regioselective synthesis of pentacyclic polyheterocycles: Sequential [3,3] sigmatropic rearrangement of 4‐(4′‐aryloxybut‐2′‐ynyloxy)‐1‐phenyl‐1,8‐naphthyridin‐2(1 H )‐ones
Author(s) -
Majumdar Krishna C.
Publication year - 2007
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.5570440420
Subject(s) - chemistry , claisen rearrangement , regioselectivity , yield (engineering) , chlorobenzene , sigmatropic reaction , anhydrous , stereochemistry , medicinal chemistry , organic chemistry , catalysis , materials science , metallurgy
A number of 4‐aryloxymethyl‐6‐phenyl‐2 H ‐pyrano[3,2‐ c ][1,8]naphthyridin‐5(6 H )‐ones ( 4a‐f ) are regioselectively synthesized in 72‐78% yield by the Claisen rearrangement of 4‐(4′‐aryloxybut‐2′‐ynyloxy)‐1‐phenyl‐1,8‐naphthyridin‐2(1 H )‐ones ( 3a‐f ) in refluxing chlorobenzene for 4‐6 h. These products are then subjected to a second Claisen rearrangement catalyzed by anhydrous AlCl 3 at room temperature for 2 h to give hitherto unreported pentacyclic heterocycles ( 5a‐f ) in 78‐85% yield.