Synthetic Nucleoside Research Articles

Synthetic nucleosides and nucleotides. IX. Synthesis of 2',5'- and 3',5'-di-O-tritylcytidine and the related compounds via thiation.

Thiation of the 2', 5'-di-O-trityl-3'-O-acetyluridine or 3', 5'-di-O-trityl-2'-O-acetyluridine with phosphorus pentasulfide in refluxing toluene containing 20-30% pyridine afforded corresponding4-thioderivative in good yield. These 4-thio derivatives were converted to the cytidine counterparts by the reaction with methanolic ammonia. 2', 5'-Di-O-trityl-3'-O-methanesulfonyluridine was also converted to cytidine derivative by similar manner. In addition, phosphorylation and dinucleoside monophosphate synthesis using titled compounds were described.

A new class of synthetic nucleoside analogues with broad-spectrum antiviral properties.

THE newly synthesized nucleoside analogue virazole (1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) belongs to the class of nucleosides of pyrazomycin and showdomycin with a five-membered heterocyclic base linked to a β-D-ribofuranose moiety1. Virazole is of considerable interest because it is the first synthetic nucleoside that shows broad-spectrum antiviral properties. The chemical characterization and biological properties of virazole have been described recently2–7. The purpose of our X-ray study was to establish unequivocally its chemical structure and conformation and to investigate its mode of action.

Suppression by 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (virazole, ICN 1229) of influenza virus-induced infections in mice.

1-beta-d-Ribofuranosyl-1,2,4-triazole-3-carboxamide (Virazole) was found to possess significant antiviral activity against aerosol-induced or intranasally induced influenza A(0), A(2), and B virus infections in mice. Significant protection was achieved by both oral and intraperitoneal routes of administration. Depending upon the level of virus infection, antiviral activity was best observed at the daily dose of 75 mg/kg. The efficacy of the compound was evidenced by an increase in survivor number, prolongation of mean survival time, suppression of lung consolidation, or decrease in hemagglutinin titer in the infected lung samples. The therapeutic value of this synthetic triazole nucleoside was evident as noted by a significant increase in survivor number even if the treatment was started as late as 24 h after infection with an aerosol of influenza A(2) virus.

Mechanism of action of 1- -D-ribofuranosyl-1,2,4-triazole-3-carboxamide (Virazole), a new broad-spectrum antiviral agent.

The antiviral activity of the synthetic nucleoside, Virazole (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide), against measles virus in Vero cell cultures was substantially reversed by xanthosine, guanosine, and to a slightly lesser extent by inosine. Virazole 5'-phosphate was subsequently found to be a potent competitive inhibitor of inosine 5'-phosphate dehydrogenase (IMP:NAD(+) oxidoreductase, EC 1.2.1.14) isolated from Escherichia coli (K(m) = 1.8 x 10(-5) M) with a K(i) of 2.7 x 10(-7) M. Guanosine 5'-phosphate (GMP) was a competitive inhibitor of this enzyme with a K(i) of 7.7 x 10(-5) M. Virazole 5'-phosphate was similarly active against IMP dehydrogenase isolated from Ehrlich ascites tumor cells, with a K(i) of 2.5 x 10(-7) M. The K(m) for this enzyme was 1.8 x 10(-5) M, and the K(i) for GMP was 2.2 x 10(-4) M. These results suggest that the antiviral activity of Virazole might be due to the inhibition of GMP biosynthesis in the infected cell at the step involving the conversion of IMP to xanthosine 5'-phosphate. This inhibition would consequently result in inhibition of the synthesis of vital viral nucleic acid.

In Vitro Effect of 1-β- d -Ribofuranosyl-1,2,4-Triazole-3-Carboxamide (Virazole, ICN 1229) on Deoxyribonucleic Acid and Ribonucleic Acid Viruses

Virazole (1-beta-d-ribofuranosyl-1,2,4-triazole-3-carboxamide) is a highly soluble new synthetic nucleoside having significant, reproducible activity against a broad spectrum of deoxyribonucleic acid and ribonucleic acid viruses in vitro. The drug inhibited viral cytopathogenic effects in monolayers of cells infected for 3 days with type 3 adeno, types 1 and 2 herpes, myxoma, cytomegalo, vaccinia, infectious bovine rhinotracheitis, types 1A, 2, 8, 13, and 56 rhino, types 1 and 3 parainfluenza, vesicular stomatitis, subacute sclerosing panencephalitis, Semliki Forest, Newcastle disease, and measles viruses. Hemagglutinin production by influenza A(2), influenza B, and type 1 parainfluenza viruses in chicken embryo cells was reduced by Virazole treatment. Recoverable intra- and extracellular virus titers were reduced by the drug in experiments with type 1 herpes, vaccinia, type 3 parainfluenza, and vesicular stomatitis viruses. Plaque formation by type 1 herpesvirus was also inhibited by exposure of the infected cells to Virazole. Pretreatment of cells with the compound, followed by its removal before addition of type 1 herpesvirus, severely lessened the antiviral activity; the compound was still moderately effective in reducing the viral effects on the cells when added as long as 22 hr after the virus. Parallel experiments, in which the antiviral activity of a number of known active drugs was compared, indicated Virazole to have at least a comparable degree of activity, and it was also active against a wider variety of viruses than any of these known active materials. The CCED(50) of Virazole to chicken embryo cells was approximately 1,000 mug/ml, although concentrations as low as 10 mug/ml caused slight (15%) inhibition in total cellular protein after 72 hr of incubation.

Broad-spectrum antiviral activity of Virazole: 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide.

Virazole is a synthetic nucleoside active in tissue culture against at least 16 DNA and RNA viruses. Applied topically, it inhibits herpetic keratitis in rabbits and tail lesions induced by herpes, vaccinia, and vesicular stomatitis viruses in mice. Injected intraperitoneally into mice, it inhibits splenomegaly and hepatomegaly induced by Friend leukemia virus and respiratory infections caused by influenza A(O), A(2), and B viruses and parainfluenza 1 virus. infections is also effective.

Synthetic Nucleosides and Nucleotides. VIII. Direct Synthesis of the 5'-Phosphate of 4-Thiouridine, 6-Thioinosine and 6-Thioguanosine from the Corresponding Oxy Nucleotide via Thiation Procedure

Direct and simple methods for the preparations of 4-thiouridine 5'-phosphate (IVa), 6-thioinosine 5'-phosphate (IVb) and 6-thioguanosine 5'-phosphate (IVc) from the corresponding oxy-nucleotides are described. The 5'-ribonucleotides are converted to their 2', 3'-di-O-acetylated derivatives by a conventional acetylation procedure, followed by thiation with phosphorus pentasulfide to give crude thiated products. For the selective desulfurization, the crude products are treated with dicyclohexylcarbodiimide, followed by alkaline deacylation to give the desired thio nucleotides.

Analogs of carbohydrate-metabolism coenzymes

This report is a continuation of work conducted at our laboratory, in conjunction with the Laboratory for Biological Testing, on the influence of changes in the heterocyclic ring of ADPG~" on its reactivity in different enzymatic reactions. For this purpose, we studied synthetic nucleoside diphosphate sugar analogs substituted at different positions in the purine ring [2]. This article describes the synthesis of two ADPG analogs substituted at the exocyclic amino group on the C 6 of the adenine ring: N6-methyl-ADPG and NG, N 6dimethyl-ADPG. The behavior of these analogs in biological reactions is of great interest, since it canaid us in determining the significance of the amino group hydrogen atoms in coenzyme biological activity. The initial compounds for synthesis of both ADPG analogs were the corresponding 5'-monophosphates. Synthesis of N6-methylamino-9-fl-D-ribofuranosylpurine-5'-phosphate (NG-methyl-AMP) (IV) was carr ied out by regrouping of Ni-methyladenosine-5'-phosphate (II), which was in turn obtained by methylation of adenosine5'-phosphate:

Synthetic nucleosides and nucleotides. VI. On the several routes for the syntheses of 4-thiouridylic acid homologues.

The following synthetic methods for the preparation of 4-thiouridylic acid homologues from uridine are described. Route A. Mild acid treatment of 2', 3'-O-isopropylidene-5'-O-benzoyl-4-thiouridine (II) followed by phosphorylation by Tener's procedure gave 4-thiouridine 2', (3')-phosphate via 5'-O-benzoyl-4-thiouridine (III). Alkali treatment of II followed by phosphorylation by Tener's procedure gave 4-thiouridine 5'-phosphate via 2', 3'-O-isopropylidene-4-thiouridine (IV). Route B. 2', 3'-Di-O-acetyl-5'-O-trityl-4-thiouridine (V) was prepared by thiation of 2, 3'-di-O-acetyl-5'-O-trityluridine. Alkali treatment of V followed by Tener's phosphorylation gave 2', (3')-phosphate of 4-thiouridine via 5'-O-trityl-4-thiouridine (VI). Mild acid treatment of V followed by Tener's phosphorylation gave 5'-phosphate of 4-thiouridine in satisfactory yield via 2', 3'-di-O-acetyl-4-thiouridine (VII). Route C. Direct phosphorylation of 4-thiouridine with excess amounts of cyanoethylphosphate and dicyclohexylcarbodiimide produced 2', (3')-mono-, 5'-mono-and 2', (3'), 5'-diphosphate of 4-thiouridine. Treatment of the diphosphate with dicyclohexylcarbodiimide gave 4-thiouridine 2', 3'-cyclic, 5'-diphosphate (VIII). 4-Thiouridine 2', 3'-cyclic phosphate (IX) was obtained by treatment of 4-thiouridine 2', (3')-phosphate with same manner or by digestion of VIII with E. coli alkaline phosphomonoesterase. 4-thiouridine 3'-phosphate was prepared by digestion of IX with bovine pancreatic ribonuclease.

Arabinosyl Cytosine: A Useful Agent in the Treatment of Acute Leukemia in Adults

Abstract Arabinosyl cytosine (ara-C), a synthetic pyrimidine nucleoside related to the normal metabolites cytidine and deoxycytidine, has been found capable of producing marrow remission at tolerable doses in acute myelocytic and acute lymphocytic leukemia in adults. There were 16 per cent remissions complete in all aspects, 3 per cent complete except for hemoglobin level, and 6 per cent partial remissions among 180 adults with acute myelocytic leukemia treated with any one of 8 variants of infusion duration or daily dose of ara-C. Twenty-four per cent of 37 adults with acute lymphocytic or unclassified leukemia had complete or partial remissions. The comparison of 1, 4, 12 and 24 hours infusion of ara-C (to total dose tolerated) does not show significant superiority for any one group. The complete remission rate with 1 or 12 hour infusions, however, is 25 per cent (superior to that obtained with 6-mercaptopurine) and the recommended schedule of treatment for ara-C based on these data is, therefore, daily infusions of 100 or 50 mg./m.2 in one hour for approximately 3 to 6 weeks followed by maintenance therapy of once weekly subcutaneous injection of 30 mg./m.2 of ara-C. Platelet transfusions should be available when ara-C is used.

Synthetic nucleosides and nucleotides. 3. On the syntheses of several 2,6,8-trisubstituted purine ribonucleosides.

Synthetic nucleosides and nucleotides. 3. On the syntheses of several 2,6,8-trisubstituted purine ribonucleosides.

Structural basis for phosphorylation of adenosine congeners.

DURING the past few years the metabolism by mammalian cells of a number of natural and synthetic nucleosides structurally related to adenosine has been investigated in this1–5 and other laboratories6–10. In our studies with Ehrlich ascites cells, we have tried to establish a correlation between the structural variations and the utilization by cells of these nucleosides and have observed the following salient features: (a) In order to be phosphorylated to the 5′-triphosphate level, the adenosine analogue must have a primary amino group at the C-6 position of the purine moiety. Compounds that belong in this category are 3′-deoxyadenosine2,6, 3′-amino-3′-deoxyadenosine4 and 2-fluoroadenosine3. These three nucleosides were also found to be potent inhibitors of nucleic acid synthesis in Ehrlich ascites cells. Work in other laboratories has shown that 7-deazaadenosine7, xylosyladenine8, arabinosyladenine9 and the bases 2-azaadenine and 2,6-diaminopurine10 were also phosphorylated to 5′-triphosphate. 2,6-Diaminopurine is also metabolized to the triphosphate level by microbial cells11,12. Removal of the 6-amino group as in 3′-deoxynebularine resulted in complete absence of phosphorylation by ascites cells*4. (b) 6-Methylaminopurine ribonucleoside—an adenosine analogue with a 6-methyl-amino group—was metabolized to the monophosphate level only4. This was also found to be so for 6-methyl-aminopurine - 2′-deoxyribonucleoside, 6-methylaminopurine-3′-deoxyribonucleoside and 6-methylaminopurine5. (c) Replacement of the 6-amino group by 3′-deoxyadenosine with an ethylamino or dimethylamino group completely suppressed the capacity of the nucleoside for phosphorylation. This relationship was exemplified by 6-ethylaminopurine-3′-deoxyribonucleoside and 6-dimethylaminopurine-3′-deoxyribonucleoside4. Furthermore, 6-dimethylamino-3′-amino-3′-deoxyribonucleoside was also inactive, while its parent compound, as already mentioned, was readily phosphorylated. Nucleosides that were not phosphorylated had almost no effect on nucleic acid synthesis.

Synthetic Nucleosides and Nucleotides. I. On Synthesis and Properties of Several Thiocyanato Derivatives of Purines and Their Ribonucleosides.

Several thiocyanato derivatives of purines and their ribonuclesides as potential antineoplastic agents, were prepared by the reaction of mercaptopurines and their ribonucleosides with cyanogen bromide. The reaction of these thiocyanato derivatives were examined with acid, alkali, sodium methoxide and Raney Ni.

Synthetic nucleosides. LXIX. Synthesis of some new types of branched-chain amino sugars.

Synthetic nucleosides. LXIX. Synthesis of some new types of branched-chain amino sugars.

Synthetic nucleosides. LXV. Studies on the synthesis of cis-2,3-diamino sugars. V. Neighboring group reactions with derivatives of methyl 2-amino-4,6-O-benzylidene-2-deoxy-alpha-D-altropyranoside.

Synthetic nucleosides. LXV. Studies on the synthesis of cis-2,3-diamino sugars. V. Neighboring group reactions with derivatives of methyl 2-amino-4,6-O-benzylidene-2-deoxy-alpha-D-altropyranoside.

Synthetic nucleosides. LXVII. Studies on the synthesis of cis-2,3-diamino sugars. VII. Synthesis and reactions of some N-p-tolylsulfonyl derivatives of 2-amino-2-deoxy-D-altrose, 3-amino-3-deoxy-D-glucose, and 2,3-dideoxy-2,3imino-D-mannose.

Synthetic nucleosides. LXVII. Studies on the synthesis of cis-2,3-diamino sugars. VII. Synthesis and reactions of some N-p-tolylsulfonyl derivatives of 2-amino-2-deoxy-D-altrose, 3-amino-3-deoxy-D-glucose, and 2,3-dideoxy-2,3imino-D-mannose.

SYNTHETIC NUCLEOSIDES. 63. SYNTHESIS AND REACTIONS OF SOME ALPHA-SULFONYLOXY OXO SUGARS.

SYNTHETIC NUCLEOSIDES. 63. SYNTHESIS AND REACTIONS OF SOME ALPHA-SULFONYLOXY OXO SUGARS.

Synthetic Nucleosides. LXII.1,2 Facile Displacement Reactions in the D-Mannitol Series. V. Studies on the Selective Conversion of Some Hexitol Derivatives to Aldoses

Synthetic Nucleosides. LXII.^1,2 Facile Displacement Reactions in the D-Mannitol Series. V. Studies on the Selective Conversion of Some Hexitol Derivatives to Aldoses

Studies on Synthetic Nucleosides

A new synthetic method of purine glucosides was described. Fusion of bis-trimethylsilyl-N-ben-zoyladenine and -hypoxanthine with α-acetobromoglucose and subsequent removal of the protecting groups gave glucopyranosyladenine and -hypoxanthine, respectively. In the former, the formation of α-glucoside was confirmed. Nuclear magnetic resonance spectra of the pyrimidine and purine glucosides were also reported.

Studies on synthetic nucleosides. I. Trimethylsilyl derivatives of pyrimidines and purines.

Pyrimidine and purine bases were readily derived to trimethylsilyl derivatives by treatment with trimethylchlorosilane-triethylamine or hexamethyldisilazane. By the infrared investigation, it was clarified that the obtained derivatives possessed aromatic ring systems and physical properties of the product were reported.