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New syntheses of pyrido[3,2‐ d ]pyrimidines
Author(s) -
Senga Keitaro,
Fukami Kiyoko,
Kanazawa Hashime,
Nishigaki Sadao
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.5570190419
Subject(s) - chemistry , phenylacetaldehyde , pyrimidine , base (topology) , condensation , aryl , dimethylformamide , medicinal chemistry , stereochemistry , organic chemistry , solvent , mathematical analysis , physics , alkyl , mathematics , thermodynamics
New synthetic routes to pyrido[3,2‐ d ]pyrimidines starting with 5‐amino‐1,3,6‐trimethyluracil (I) or 1,3,6‐trimethyl‐5‐nitrouracil (X) are described. Thus, condensation of I with arylaldehydes gave 5‐arylideneamino‐1,3,6‐trimethyluracils (IIa‐h), which upon heating with dimethylformamide dimethylacetal afforded 6‐aryl‐1,3‐dimethylpyrido[3,2‐ d ]pyrimidine‐2,4(1 H ,3 H )‐diones (Va‐h) via 5‐arylideneamino‐1,3‐dimethyl‐6‐(2‐dimethylaminovinyl)uracils (IIIa‐h). On the other hand, reaction of X with phenylacetaldehyde in the presence of base yielded Va and its 5‐oxide (XI).