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Reaction of pyromeconic acid with β‐diazopropionic ester. Synthesis and attempted cyclization of β‐(4 H ‐pyran‐4‐on‐3‐yloxy)propionic acid
Author(s) -
Looker James H.,
Brannigan Lawrence H.,
Prokop Robert J.
Publication year - 1975
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.5570120320
Subject(s) - chemistry , decarboxylation , pyran , alkylation , hydrolysis , benzoic acid , propionate , organic chemistry , ring (chemistry) , medicinal chemistry , catalysis
A procedure which utilizes a special sublimate condenser for preparation of pyromeconic acid (I) by decarboxylation of either meconic or comenic acid is reported. O ‐Alkylation of pyromeconic acid with ethyl β‐diazopropionate ex situ yields ethyl β‐(4 H ‐pyran‐4‐on‐3‐yloxy)‐propionate (II), acidic hydrolysis of which affords the free acid III. The acid III is refractory to ring‐closure to a chromanone analog IV under a wide range of acidic conditions. O ‐Allylation of 1 gives 3‐allyloxy‐4 H ‐pyran‐4‐one (V) as a low‐melting crystalline solid.