Synfacts 2011(8): 0823-0823  
DOI: 10.1055/s-0030-1260849
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart ˙ New York

Effects of Addition Rate on the Synthesis of Pyridopyrimidinediones

Contributor(s): Victor Snieckus, Matthew O. Kitching
G. H. Churchill*, S. A. Raw, L. Powell
AstraZeneca, Macclesfield, UK
Further Information

Publication History

Publication Date:
20 July 2011 (online)

Significance

Reported is an improved protocol for the synthesis of pyridopyrimidinediones 3 from enaminones 2 and 6-aminouracil 1. When 2 was added to the reaction in one portion, 3 was formed in low yield. In addition, formation of by­products 4 and 5, originating from the dimerization of 2, were observed. Slow addition of 2 alleviated this issue and allowed electron-poor and electron-rich enaminones to be used, affording the product in good yield.