Pyridopyrimidines of Biological Interest

A number of deaza analogs of pteroic acid (182, Ri = R2 = OH) have been prepared and examined by Rydon el al. as antagonists of folic acid in Streptococcus faecalis and Lactobacillus casei. Two of the pyrido[3,2-d]pyrimidines (183, R = OH or OEt, R2 = NH2) showed 

Hitchings and his co-workers have made a comprehensive studyof antifolic acid activity in 2,4-diaminopyrimidines. They have demonstrated that very many such compounds, both simple and fused, show such activity. In the course ofthis work some pyrido[3,2-d]-pyrimidines and a large number of pyrido[2,3-d]pyrimidinesi  

Early reports of analgesic and antiarthritic activity in octahydropjTido[4,3-d]pyrimidines do not appear to have been substantiated, but a number of recent patents refer to the antipyretic, diuretic, bacteriostatic, sedative, and coronary-dilating activities of a series of 5,6,7,8-tetrahydropyrido[4,3-d]pyrimidines. Pharmacological properties claimed for, 5,6-dihydropyrido[2,3- Z]-pyrimidines and pyrido[2,3-d]pyrimidine-2 4,.5,7-tetraones have not yet been confirmed. 

Jacobsen, in Biological Approaches to Cancer Chemotherapy (R. V. C. Harris, ed.), p. 149. Academic Press, New York, 1961. 

Department of Chemistry, Monash University, Clayton, Victoria, Australia 

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G. Reactive Methyl Groups Pyridopyrimidines of Biological Interest... 

The field of pyridopyridazines, although potentially a rich one, has been little explored compared with that of the pyridopyrimidines. This is due partly to the difficulty of preparation of several of the member systems, to the relatively small number of different syntheses utilized for those systems which have been explored, and the relative lack of interesting biological activity, or pharmaceutical and other uses found with them. 

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