Several compounds of 3,9-dialkylxanthines were prepared from 1-methyl-6-chlorouracil via nucleophillic reactions with different aliphatic amines, followed by nitrosation, reduction, formaylation and finally dehydrocyclization. On the other hands, a series of 8-aryl-3,9-dimethylxanthines were synthesized by dehydrocyclization of 5-arylamido-1-methyl-6-methylaminouracils either by fussion or oxidation of 5-arylidine-amino-1-methyl-6-methylaminouracils using sodium periodate. Phosphoryl chloride was found to be uneffective reagent for dehydrocyclization that, gave another products from 1,3-oxazolo[5,4-d] pyrimidines.