Enantioselective synthesis of iclaprim enantiomers--a versatile approach to 2-substituted chiral chromenes

J Org Chem. 2010 Jun 4;75(11):3781-5. doi: 10.1021/jo100566c.

Abstract

Both enantiomers of the DHFR inhibitor iclaprim (R)-1 and (S)-1 were synthesized from the cyclopropyl homoallyl alcohols (R)-6 and (S)-6, respectively. As key steps these transformations include a Mitsunobu reaction and the formation of the diaminopyrimidine unit prior to a novel cyclization procedure to obtain the desired chromene heterocycle. The moderate enantioselectivity of the products (R)-1 and (S)-1 is related to the Mitsunobu reaction, which unfortunately did not proceed with complete inversion of configuration.

MeSH terms

  • Alcohols / chemistry
  • Benzopyrans / chemical synthesis*
  • Folic Acid Antagonists / chemical synthesis
  • Pyrimidines* / chemical synthesis
  • Stereoisomerism
  • Tetrahydrofolate Dehydrogenase

Substances

  • Alcohols
  • Benzopyrans
  • Folic Acid Antagonists
  • Pyrimidines
  • iclaprim
  • Tetrahydrofolate Dehydrogenase