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Acid‐catalyzed cyclization of alkoxyacryloylureas to 2,4(1H,3H)pyrimidinediones
Author(s) -
Shealy Y. Fulmer,
O'Dell C. Allen
Publication year - 1976
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.5570130521
Subject(s) - chemistry , catalysis , trifluoroacetic acid , sulfuric acid , aqueous solution , acetic acid , thymine , urea , ammonia , organic chemistry , medicinal chemistry , cleavage (geology) , biochemistry , dna , geotechnical engineering , fracture (geology) , engineering
1‐Phenylthymine and the carbocyclic analog of thymidine were obtained in yields of 84‐87% by cyclizing the appropriate 3‐methoxy‐2‐methylacryloylureas in dilute sulfuric acid. High yields of 1‐phenylthymine also resulted when the cyclization was carried out in trifluoroacetic acid, in acetic acid containing toluenesulfonic acid (TSA), or by fusion of the urea with a catalytic amount of TSA. In comparison, the typical aqueous‐alkali catalyzed cyclizations gave lower yields of the two thymines, and cleavage of the acryloylureas was shown to occur. However, cyclization in concentrated aqueous ammonia produced high yields of both thymine derivatives.