Convenient and Versatile Synthetic Methods for Furazano[3,4-d]pyrimidines
作者:Magoichi Sako、Souichi Oda、Kosaku Hirota、George P. Beardsley
DOI:10.1055/s-1997-1349
日期:1997.11
Treatment of the readily available 6-amino-5-nitrosopyrimidines with a slight excess of iodobenzene diacetate or N-iodosuccinimide in anhydrous DMF containing three equivalents of lithium hydride at ambient temperature resulted in the smooth and versatile formation of the corresponding furazano[3,4-d]pyrimidines, which are useful intermediates for the preparation of biologically interesting fused pyrimidines.
Mechanistic aspects of the oxidation of 1,3-disubstituted 6-amino-5-nitrosouracils with lead tetraacetate: the formation of pyrimido[5,4-g]pteridinetetrone 10-oxides
作者:Magoichi Sako、Seiji Ohara、Kosaku Hirota、Keuji Kano、Yoshifumi Maki、Edward C. Taylor
DOI:10.1021/jo00022a017
日期:1991.10
Lead tetraacetate oxidation of 1,3-disubstituted 6-amino-5-nitrosouracils 1 in glacial acetic acid results in the formation of 1,3,6,8-tetrasubstituted pyrimido[5,4-g]pteridine-2,4,5,7(1H,3H,6H,8H)-tetrone 10-oxides 2. ESR studies and a number of chemical observations suggest a novel reaction sequence involving oxidative dimerization of 1 followed by intramolecular cyclization, oxidation, and homolytic elimination of nitrous oxide.