Reduction pyrimidines

Base stacking will further modulate the reduction potentials. Initial calculations show that pyrimidines flanked by other pyrimidines, like in 3 -TTT-5 or 3 -TCT-5 sequences, are most easily reduced. Incorporation of a purine base close to the pyrimidine, however, seems to make the pyrimidine reduction more difficult [40]. 

In modern medicinal chemistry, the creation of diversity on a structural framework is important. In principle, diversity at positions 2, 4, 6, 7, and 8 of pteridines can be achieved using such solid-phase chemistry. This prototype solid-phase synthesis involved nitrosation of the resin-bound pyrimidine, reduction of nitroso group with sodium dithionite, and subsequent cyclization with biacetyl to afford pteridines 114 and 115. Cleavage from the resin by nucleophilic substitution of the oxidized sulfur linker using w-chloroperbenzoic acid or DMDO led to the pteridine products 116 and 117 (Scheme 23). 

Most pteridines are degraded to pyrazines and when they do yield pyrimidines, these may well be the ones from which they were made. However, some useful preparations of pyrimidines from pteridines are known. Thus, reduction of pteridin-7(8//)-one (732) and subsequent hydrolysis yields N-(4-aminopyrimidin-5-yl)glycine (733) (52JCS1620) and hydrolysis of 5,8-dimethylpteridine-6,7(5Ff,8Ff)-dione (734) gives dimethyl-... 

The simplest pyrimidine antibiotic is bacimethrin, 5-hydroxymethyl-2-methoxypyrimidin-4-amine (985), which was isolated in 1961 from Bacillus megatherium and is active against several yeasts and bacteria in vitro as well as against staphylococcal infections in vivo it has some anticarcinoma activity in mice (69MI21301). It may be synthesized by LAH reduction of ethyl 4-amino-2-methoxypyrimidine-5-carboxylate (984) which may be made by primary synthesis in poor yield, or better, from the sulfone (983) (B-68MI21304). 

A reversal of the position of the substituents on the pyrimidine ring is involved in the reductive cyclization of 4-ketoalkyl-5-phenylazopyrimidines to give, e.g. 6-alkylpyrido[3,2- f]pyrimidines (76JHC439). 

Furazano[3,4-d]pyrimidine, 7-amino-synthesis, 6, 729 UV spectra, 6, 713 Furazanopyrimidines amine synthesis from, 5, 591 synthesis, 6, 418 Furazano[3,4-d]pyrimidines nucleophilic attack, 6, 719 nucleophilic substitution, 6, 713 reduction, 6, 402 7-substituted reactions, 6, 722 Furazano[3,4-a]quinolizines synthesis, 6, 730... 

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