title: Improved synthesis of zebularine [1-(beta-D-ribofuranosyl)-dihydropyrimidin-2-one] nucleotides as inhibitors of human deoxycytidylate deaminase.
abstract: The 2'-deoxy (2a) and 2'-ara-fluoro (3a) derivatives of zebularine [1-(beta-D-ribofuranosyl)-dihydropyrimidin-2-one, 1a] were phosphorylated in high yield to the 5'-nucleotides 2b and 3b, respectively, and characterized by HPLC, enzyme degradation, 1H, 13C and 31P NMR, and high resolution mass spectral analysis. Their inhibitory activity against partially purified MOLT-4 deoxycytidylate deaminase (dCMPD) in the presence of the allosteric effector deoxycytidine triphosphate (dCTP) and Mg+2 ion was examined. Compounds 2b and 3b inhibited dCMPD with Ki values of 2.1 x 10(-8) M and 1.2 x 10(-8) M, respectively. The parent nucleotide, zebularine monophosphate 1b was ineffective at concentrations > 100 mumol. The effect of the nucleosides, 1a-3a, as well as tetrahydrouridine (THU) and 2'-deoxy THU (dTHU), on the cellular production of DNA precursors was examined in human MOLT-4 peripheral lymphoblasts. It was shown that 1a, 2a and 3a all elevated intracellular dCTP and TTP levels in whole cells with the most powerful effect elicited by 1a. The 2'-fluoro derivative 3a was chemically phosphorylated much more cleanly and higher yield than 2a, without the formation of diphosphorylated by-products. This compound was found to be infinitely less sensitive to acid-catalyzed degradation than 2a. Since the substitution of fluorine for hydrogen had a slight potentiating effect on the dCMPD inhibitory activity while stabilizing the compound toward acid-catalyzed and enzymatic depyrimidination, compound 3b emerges as a very attractive tool for the pharmacological modulation of pyrimidine deaminase activity.
authors.affiliation: Laboratory of Medicinal Chemistry, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Barchi
authors.forename: D A
authors.initials: DA
authors.lastname: Cooney
authors.forename: Z
authors.initials: Z
authors.lastname: Hao
authors.forename: Z H
authors.initials: ZH
authors.lastname: Weinberg
authors.forename: C
authors.initials: C
authors.lastname: Taft
authors.forename: V E
authors.initials: VE
authors.lastname: Marquez
authors.forename: H
authors.initials: H
authors.lastname: Ford
mesh_terms: D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D003562:Cytidine / Q000031:analogs & derivatives; D003844:DCMP Deaminase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism; D003854:Deoxyribonucleotides / Q000378:metabolism; D004355:Drug Stability; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008214:Lymphocytes / Q000201:enzymology / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D011741:Pyrimidine Nucleosides / Q000138:chemical synthesis* / Q000302:isolation & purification / Q000494:pharmacology; D011742:Pyrimidine Nucleotides / Q000138:chemical synthesis* / Q000302:isolation & purification / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D003854:Deoxyribonucleotides; D004791:Enzyme Inhibitors; D011741:Pyrimidine Nucleosides; D011742:Pyrimidine Nucleotides; D003562:Cytidine; C009131:pyrimidin-2-one beta-ribofuranoside; D003844:DCMP Deaminase