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6‐ And 7‐Substituted 4 H ‐Pyrido[1,2‐ a ] pyrimidin‐4‐ones. Synthesis via the Acid‐catalyzed Isomerization of 2‐(Acetoacetamido)pyridines
Author(s) -
Yale Harry L.,
Spitzmiller E. R.
Publication year - 1977
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.5570140420
Subject(s) - chemistry , isomerization , catalysis , pyridine , medicinal chemistry , stereochemistry , combinatorial chemistry , organic chemistry
A novel procedure has been developed for converting a variety of substituted 2‐(aceto‐acetamido)pyridines into substituted 4 H ‐pyrido[1,2‐ a ]pyrimidin‐4‐ones. The reaction involves an acid‐catalyzed isomerization of the 2‐(acetoacetamido)pyridine derivatives into the corresponding enamines , under conditions that permit the latter to undergo cyclization to the 4‐one, in situ . The method has been employed to prepare a number of hitherto unknown 2,6‐ and 2,7‐di‐ and 2,7,9‐trisubstituted 4 H ‐pyrido[1,2‐ a ]pyrimidin‐4‐ones.