- Specific Inhibitors in Vitamin Biosynthesis. Part 9. Reactions of 7,7-Dialkyl-7,8-dihydropteridines of Use in the Synthesis of Potential Inhibitors of Tetrahydrofolate Biosynthesis.
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Reactions of 7,7-dialkyl-7,8-dihydropteridines which are of potential use in modifying substituents on the pyrazine ring to yield compounds with inhibitory activity against 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase and dihydrofolate reductase are described.These enzymes lie along the pathway leading to the coenzyme tetrahydrofolate. 6-Methyl substituents showed typical reactivity of alkyl groups α- to a pyrazine nitrogen atom and underwent exchange of protium for deuterium under acidic and basic conditions: however, they failed to undergo clean bromination or aldol condensation.Autoxidation of alkyl groups at this position provided ready access to pteridines substituted with carbonyl groups at C-6. 6-Formyl derivatives underwent Wittig-type reactions to yield 6-aralkylidene compounds that are potential inhibitors of dihydrofolate reductase.Alkylation of the anion of 2,4-diamino-7,8-dihydro-6,7,7-trimethylpteridine occured at N-8 in low yield.The reduction of the blocked dihydropteridine system was readily accomplished using catalytic hydrogenation in a manner analogous to that used for normal pteridines.
- Al-Hassan, Saiba S.,Cameron, Robert,Nicholson, Sydney H.,Robinson, David H.,Suckling, Colin J.,Wood, Hamish C. S.
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