Design, synthesis, and biological evaluation of classical and nonclassical 2-amino-4-oxo-5-substituted-6-methylpyrrolo[3,2-d]pyrimidines as dual thymidylate synthase and dihydrofolate reductase inhibitors

J Med Chem. 2008 Jan 10;51(1):68-76. doi: 10.1021/jm701052u. Epub 2007 Dec 12.

Abstract

We designed and synthesized a classical antifolate N-{4-[(2-amino-6-methyl-4-oxo-3,4-dihydro-5 H-pyrrolo[3,2- d]pyrimidin-5-yl)methyl]benzoyl}- l-glutamic acid 4 and 11 nonclassical analogues 5- 15 as potential dual thymidylate synthase (TS) and dihydrofolate reductase (DHFR) inhibitors. The key intermediate in the synthesis was N-(4-chloro-6-methyl-5 H-pyrrolo[3,2- d]pyrimidin-2-yl)-2,2-dimethylpropanamide, 29, to which various 5-benzyl substituents were attached. For the classical analogue 4, the ester obtained from the N-benzylation reaction was deprotected and coupled with diethyl l-glutamate followed by saponification. Compound 4 was a potent dual inhibitor of human TS (IC 50 = 46 nM, about 206-fold more potent than pemetrexed) and DHFR (IC 50 = 120 nM, about 55-fold more potent than pemetrexed). The nonclassical analogues were marginal inhibitors of human TS, but four analogues showed potent T. gondii DHFR inhibition along with >100-fold selectivity compared to human DHFR.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antineoplastic Agents / chemical synthesis
  • Antineoplastic Agents / chemistry
  • Drug Design
  • Escherichia coli / enzymology
  • Folic Acid Antagonists / chemical synthesis*
  • Folic Acid Antagonists / chemistry
  • Humans
  • Models, Molecular
  • Pyrimidines / chemical synthesis*
  • Pyrimidines / chemistry
  • Pyrroles / chemical synthesis*
  • Pyrroles / chemistry
  • Structure-Activity Relationship
  • Tetrahydrofolate Dehydrogenase / chemistry*
  • Thymidylate Synthase / antagonists & inhibitors*
  • Thymidylate Synthase / chemistry*
  • Toxoplasma / enzymology

Substances

  • Antineoplastic Agents
  • Folic Acid Antagonists
  • Pyrimidines
  • Pyrroles
  • Tetrahydrofolate Dehydrogenase
  • Thymidylate Synthase