The synthesis of a series of adenosine A3 receptor agonists

Org Biomol Chem. 2016 Apr 12;14(15):3765-81. doi: 10.1039/c6ob00244g.

Abstract

A series of 1'-(6-aminopurin-9-yl)-1'-deoxy-N-methyl-β-d-ribofuranuronamides that were characterised by 2-dialkylamino-7-methyloxazolo[4,5-b]pyridin-5-ylmethyl substituents on N6 of interest for screening as selective adenosine A3 receptor agonists, have been synthesised. This work involved the synthesis of 2-dialkylamino-5-aminomethyl-7-methyloxazolo[4,5-b]pyridines and analogues that were coupled with the known 1'-(6-chloropurin-9-yl)-1'-deoxy-N-methyl-β-d-ribofuranuronamide. The oxazolo[4,5-b]pyridines were synthesized by regioselective functionalisation of 2,4-dimethylpyridine N-oxides. The regioselectivities of these reactions were found to depend upon the nature of the heterocycle with 2-dimethylamino-5,7-dimethyloxazolo[4,5-b]pyridine-N-oxide undergoing regioselective functionalisation at the 7-methyl group on reaction with trifluoroacetic anhydride in contrast to the reaction of 4,6-dimethyl-3-hydroxypyridine-N-oxide with acetic anhydride that resulted in functionalisation of the 6-methyl group. To optimise selectivity for the A3 receptor, 5-aminomethyl-7-bromo-2-dimethylamino-4-[(3-methylisoxazol-5-yl)methoxy]benzo[d]oxazole was synthesised and coupled with the 1'-(6-chloropurin-9-yl)-1'-deoxy-N-methyl-β-d-ribofuranuronamide. The products were active as selective adenosine A3 agonists.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / analogs & derivatives
  • Adenosine / chemical synthesis
  • Adenosine / pharmacology
  • Adenosine A3 Receptor Agonists / chemical synthesis*
  • Adenosine A3 Receptor Agonists / chemistry
  • Adenosine A3 Receptor Agonists / pharmacology*
  • Crystallography, X-Ray
  • Humans
  • Models, Molecular
  • Oxazoles / chemical synthesis
  • Oxazoles / chemistry
  • Oxazoles / pharmacology
  • Pyridines / chemical synthesis
  • Pyridines / chemistry
  • Pyridines / pharmacology
  • Receptor, Adenosine A3 / metabolism*

Substances

  • Adenosine A3 Receptor Agonists
  • Oxazoles
  • Pyridines
  • Receptor, Adenosine A3
  • oxazolo(3,2-a)pyridine
  • Adenosine