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Pyrimidines. 20. Novel reactions of 5‐cyano‐1,3‐dimethyluracil. A simple synthesis of pyrido[2,3‐ d ]pyrimidines
Author(s) -
Su TsannLong,
Watanabe Kyoichi A.
Publication year - 1982
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.5570190563
Subject(s) - chemistry , malononitrile , pyrimidine , ketone , yield (engineering) , acetone , bicyclic molecule , butanone , ethyl cyanoacetate , medicinal chemistry , base (topology) , stereochemistry , organic chemistry , catalysis , solvent , mathematical analysis , materials science , mathematics , metallurgy
A reaction of 5‐cyano‐1,3‐dimethyluracil (1, R = CN) with acetone in base afforded 1,3,7‐trimethylpyrido‐[2,3‐ d ]pyrimidine‐2,4(1 H ,3 H )dione ( 9a ) in a moderate yield. From a reaction mixture of 1 (R = CN) with butanone, 1,3,6,7‐tetramethyl‐ and 7‐ethyl‐1,3‐dimethylpyrido[2,3‐ d ]pyrimidine‐2,4(1 H ,3 H )‐dione ( 9b and 9c , respectively) were isolated in low yields. When ethyl cyanoacetate or malononitrile was used in place of the ketone in the above reaction, 7‐amino‐6‐ethoxycarbonyl‐ and 7‐amino‐6‐cyano‐1,3‐dimethylpyrido[2,3‐ d ]‐pyrimidine‐2,4(1 H ,3 H )‐dione ( 14a and 14b , respectively) were obtained in quantitative yields. A plausible mechanism for the formation of bicyclic compounds is discussed.