Methylated Purines and Pyrimidines. II. Synthesis and Properties of 2,6-Diamino-5-(methylamino)-4-pyrimidinol

M. Sprecher, D. B. Sprinson

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2,6-Diamino-5-(methylamino)-4-pyrimidinol (compound VIII) was synthesized by an application of the Hinsberg reaction. Sulfonylation of 2,4,5-triamino-6-methoxypyrimidine (compound lb) gave the 5-sulfonamidopyrimidines II and VI, which were methylated to the corresponding 5-(N-methylsulfonamido)pyrimidines (compounds III and VII). Removal of the sulfonyl group by reduction with sodium in liquid ammonia, and of the O-methyl group with HBr in acetic acid or with concentrated aqueous acid, gave compound VIII in good yields. The 5-(methylamino)pyrimidine was considerably more stable than the unmethylated compound (la) in hot acids, or in alkali in the presence of oxygen. Rather vigorous conditions appeared necessary to cyclize the 5-(N-methylformamido)- and 5-(l-methylureido)pyrimidines derived from compound VIII to 7-methylguanine and 8-hydroxy-7-methylguanine, respectively. Heating of compound VIII with ethyl oxalate gave 5-methylleucopterin (compound IX). Preliminary attempts failed to convert compound VIII to 5-methylfolic acid. Unlike 2,5,6-triamino-4-pyrimidinol (compound la), compound VIII did not appear to react with 2,3-dibromopropanal plus p-amino-benzoylglutamate. When compound VIII was treated with 2-bromo-3,3'-diethoxypropanal the reaction was very slow compared to that observed with compound la. There was no evidence for the formation of a di-hydropteridin or a pteridin.

Original languageEnglish
Pages (from-to)655-661
Number of pages7
Issue number4
StatePublished - 1 Apr 1965


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