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A new base‐induced ring transformation of pyrido[2,3‐ d ]pyrimidines
Author(s) -
Matsumoto JunIchi,
Mishio Shinsaku,
Minami Shinsaku
Publication year - 1979
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.5570160616
Subject(s) - chemistry , pyrimidine , sodium ethoxide , substituent , ring (chemistry) , solvent , transformation (genetics) , quinoline , stereochemistry , base (topology) , medicinal chemistry , ethanol , organic chemistry , biochemistry , gene , mathematical analysis , mathematics
8‐Substituted 5,8‐dihydro‐5‐oxopyrido[2,3‐ d ]pyrimidine‐6‐carboxylates ( 3 ) rearranged to 8‐substituted 7,8‐dihydro‐5‐hydroxy‐7‐oxopyrido[2,3‐ d ]pyrimidine‐6‐carboxaldehydes ( 5 ) when treated with sodium ethoxide in an aprotic polar solvent at room temperature. The 6‐cyano analogue ( 18 ) also underwent ring transformation under the same mild conditions giving 7‐amino‐8‐ethyl‐5,8‐dihydro‐5‐oxopyrido[2,3‐ d ]pyrimidine‐6‐carboxaldehyde ( 21 ). However, the ring transformations of the pyrido[2,3‐ d ]pyrimidine bearing no N 8 ‐substituent ( 12 ), ethyl 1‐ethyl‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐ ( 14 ) and ‐quinoline‐3‐carboxylates ( 16 ) failed to occur. A mechanism is discussed.