title: Synthesis and cytotoxicity of 9-(2-deoxy-2-alkyldithio-beta-D-arabinofuranosyl)purine nucleosides which are stable precursors to potential mechanistic probes of ribonucleotide reductases.
abstract: A series of 2[prime or minute]-thionucleosides, as potential inhibitors of ribonucleotide reductases, has been synthesized. Treatment of the 3[prime or minute],5[prime or minute]-O-TPDS-2[prime or minute]-O-(trifluoromethanesulfonyl)adenosine with potassium thioacetate gave the arabino epimer of 2[prime or minute]-S-acetyl-2[prime or minute]-thioadenosine which was deacetylated to give 9-(3,5-O-TPDS-2-thio-[small beta]-d-arabinofuranosyl)adenine in high yield. Treatment of the latter with diethyl azodicarboxylate-C(3)H(7)SH-THF gave 2[prime or minute]-propyl disulfide which was desilylated to give 9-(2-deoxy-2-propyldithio-[small beta]-d-arabinofuranosyl)adenine. Subsequent tosylation (O5[prime or minute]) and displacement of the tosylate with pyrophosphate afforded the 5[prime or minute]-O-diphosphate in a stable form as propyl mixed-disulfide, which upon treatment with dithiothreitol releases 9-(2-thio-[small beta]-d-arabinofuranosyl)adenine 5[prime or minute]-diphosphate. The arabino 2[prime or minute]-mercapto group might interact with the crucial thiyl radical at cysteine 439 leading to the inhibition of ribonucleotide reductases via formation of a Cys439-2[prime or minute]-mercapto disulfide bridge. The 2,6-diamino-, 2-amino-6-chloro- and 2-amino-6-methoxypurine ribosides were also converted to the corresponding 2[prime or minute]-deoxy-2[prime or minute]-propyldithio-[small beta]-d-arabinofuranosyl nucleosides, which might serve as convenient precursors to the arabino epimer of 2[prime or minute]-thioguanosine. Analogously, 2[prime or minute]-deoxy-2[prime or minute]-propyldithioadenosine was prepared from 9-([small beta]-d-arabinofuranosyl)adenine. The nucleoside disulfides show modest cytotoxicity in a panel of human tumor cell lines.
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA. wnuk@fiu.edu
authors.forename: Stanislaw F
authors.initials: SF
authors.lastname: Wnuk
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Lewandowska
authors.forename: Dania R
authors.initials: DR
authors.lastname: Companioni
authors.forename: Pedro I
authors.initials: PI
authors.lastname: Garcia
authors.forename: John A
authors.initials: JA
authors.lastname: Secrist
mesh_terms: D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000633:toxicity*; D005562:Formazans / Q000032:analysis; D006801:Humans; D011684:Purine Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry / Q000633:toxicity*; D012264:Ribonucleotide Reductases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D013872:Thionucleosides / Q000138:chemical synthesis* / Q000737:chemistry / Q000633:toxicity*
chemical_list: D004791:Enzyme Inhibitors; D005562:Formazans; D011684:Purine Nucleosides; D013872:Thionucleosides; D012264:Ribonucleotide Reductases