A general synthesis of 5,7-diaminoimidazo[4,5-b]pyridine ribosides ('2-amino-1-deazaadenosines') from 5-amino-4-imidazolecarboxamide riboside (AICA riboside)

Autor:	Francis John E, Michael A. Moskal
Rok vydání:	1992
Předmět:	Phosphoryl chloride Stereochemistry Organic Chemistry General Chemistry Riboside Catalysis Sodium hydride chemistry.chemical_compound chemistry Hydrogenolysis Pyridine Moiety Derivative (chemistry) Acetamide
Zdroj:	Canadian Journal of Chemistry. 70:1288-1295
ISSN:	1480-3291 0008-4042
Popis:	A short general synthesis of 5-substituted 5,7-diaminoimidazo[4,5-b]pyridines from 5-amino-4-imidazolecarboxamide riboside (AICA riboside) was designed to prepare isosteres of substituted 2-aminoadenosines that are selective adenosine A2 receptor agonists. AICA riboside was converted to a hydroxyl-protected 5-amino-4-imidazolecarbonitrile riboside and reacted with an N,N-disubstituted acetamide in the presence of phosphoryl chloride. Sodium hydride treatment completed the ring closure and introduced the 7-amino group. The hydroxyl protecting groups were removed under standard conditions. N-Substitution of the acetamide by one benzyl moiety led to a 5-N-substituted derivative through hydrogenolysis whereas N,N-dibenzylacetamide led to the 5,7-diamino compound. A 6-methyl analog was obtained from an N,N-disubstituted propionamide. This synthesis may be adapted to other heterocyclic systems, as illustrated by the preparation of an example of the imidazo[4,5-b]pyrrolo[3,2-e]pyridine ring system.
Databáze:	OpenAIRE
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