title: Synthesis and biological evaluation of DL-4,4-difluoroglutamic acid and DL-gamma,gamma-difluoromethotrexate.
abstract: DL-4,4-Difluoroglutamic acid (DL-4,4-F2Glu) and its methotrexate analogue, DL-gamma,gamma-difluoromethotrexate (DL-gamma,gamma-F2MTX), were synthesized and evaluated as alternate substrates or inhibitors of folate-dependent enzymes. Synthesis of DL-4,4-F2Glu involved the nitroaldol reaction of ethyl nitroacetate with a difluorinated aldehyde ethyl hemiacetal as a key step. Attempted ligation of DL-4,4-F2Glu to methotrexate (MTX), catalyzed by human folylpoly-gamma-glutamate synthetase (FPGS), revealed that DL-4,4-F2Glu is a poor alternate substrate. DL-gamma,gamma-F2MTX was synthesized by a route proceeding through N-[4-(methylamino)benzoyl]-4,4-difluoroglutamic acid di-tert-butyl ester followed by alkylation with 6-(bromomethyl)-2,4-pteridinediamine hydrobromide. DL-gamma,gamma-F2MTX was found to be neither a substrate nor an inhibitor of human FPGS. The fluorinated analogue of MTX, however, inhibits DHFR and cell growth with the same potency as MTX.
authors.affiliation: Department of Medicinal Chemistry, University of Michigan, Ann Arbor 48109, USA.
authors.forename: T
authors.initials: T
authors.lastname: Tsukamoto
authors.forename: T
authors.initials: T
authors.lastname: Kitazume
authors.forename: J J
authors.initials: JJ
authors.lastname: McGuire
authors.forename: J K
authors.initials: JK
authors.lastname: Coward
mesh_terms: D000630:Aminopterin / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D005493:Folic Acid Antagonists / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D005971:Glutamates / Q000138:chemical synthesis* / Q000494:pharmacology*; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008727:Methotrexate / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology; D015394:Molecular Structure; D010453:Peptide Synthases / Q000037:antagonists & inhibitors / Q000378:metabolism; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D005493:Folic Acid Antagonists; D005971:Glutamates; C097770:gamma,gamma-difluoromethotrexate; C097769:4,4-difluoroglutamic acid; D018698:Glutamic Acid; D013762:Tetrahydrofolate Dehydrogenase; D010453:Peptide Synthases; C023103:folylpolyglutamate synthetase; D000630:Aminopterin; D008727:Methotrexate