Synthesis of Triazole Nucleoside Derivatives

Abstract

5′-O-Mesyl-2′,3′-O-isopropylidene ribonucleosides (4 and 12) were converted to their 5′-substituted nucleosides in good yields by reacted with NaN₃ or KI. 2′,3′-O-Isopropylidene ribonucleosides (3 and 11) were prepared in good yields from ribonucleosides 1 and 2 with a reaction mixture of acetone and triethyl orthoformate instead of using acetone diethyl acetal. Compound 1 or 2 was treated with 2-acetoxyisobutyryl halide (Cl or Br) to give 1-[2-O-acetyl-3-halo-3-deoxy-5-O-(2,5,5-trimethyl-1,3-dioxolan-4-on-2-yl)-β-D-xylofuranosyl]-1,2,4-triazole-3-carboxamide (19, 22, and 23) in high yields. Instead of using 2-acetoxyisobutyryl bromide, the mixture of 2-acetoxyisobutyryl chloride and NaBr was employed in the synthesis of 22 and 23. Treatment of 19 with an activated Zn/Cu couple and deprotection gave 2′,3′-anhydro nucleoside (21), and treatment of 22 and 23 with an activated Zn/Cu couple and a little of HOAc and deprotection gave corresponding 2′,3′-unsaturated triazole nucleosides (24 and 25), respectively. The biological activity of the compounds (7 ～ 10, 15 ～ 18, and 24) was examined in human liver cancer cells (A-549), lung cancer cells (BEL-7402), and Flu-A cells.

Synthesis of Triazole Nucleoside Derivatives

All authors

Zicheng Li, Shuhua Chen, Ning Jiang & Gang Cui

https://doi.org/10.1081/NCN-120022032

Published online:

07 February 2007

Compound 1.     

2.

Synthesis of 3′-Amino-3′-Deoxyguanosine and 3′-Amino-3′-Deoxyxyloguanosine Monophosphate Hepdirect Prodrugs from Guanosine     

Brett C. Bookser  Nicholas B. Raffaele  K. Raja Reddy  Kevin Fan  Wenjian Huang  Mark D. Erion 《Nucleosides, nucleotides & nucleic acids》2013,32(10):969-986

     

3.

Using water chemistry to define ecological preferences within the moss genus Scorpidium,from Wales,UK     

Jonathan Graham  Gareth Farr  Lars Hedenäs  Aurelie Devez  Michael J. Watts 《Journal of bryology》2013,35(3):197-204

ABSTRACT

Introduction

Three Scorpidium species: S. scorpioides, S. cossonii and S. revolvens are often associated with habitats of high conservation value. This is the first attempt to define the chemical niches for these Scorpidium species in Wales (UK) and allows us to compare these with earlier European datasets.     

4.

Anthropogenic pressures within the breeding range of the Hen Harrier Circus cyaneus in Ireland     

Anthony Caravaggi  Sandra Irwin  John Lusby  Marc Ruddock  Allan Mee  Tony Nagle 《Bird Study》2019,66(4):461-470

ABSTRACT

Capsule

Patterns in the frequency and co-occurrence of anthropogenic pressures associated with suitable breeding habitat for Hen Harriers Circus cyaneus demonstrates the need for specific, focussed management and policy options aimed at mitigating impacts on this threatened population.     

5.

MOLECULAR MODELLING OF 2′-OH MEDIATED HYDROGEN BONDING IN RIBONUCLEOS(T)IDES BY NMR CONSTRAINED AM1 AND MMX CALCULATIONS     

《Nucleosides, nucleotides & nucleic acids》2013,32(4-7):1211-1217

The intra- and intermolecular hydrogen bonding (ΔGº_298K ≈ 2, kcal mol^?1) of 2′-OH in nucleos(t)ides has been reported by the temperature- and concentration-dependent NMR study in conjunction with dihedral dependence of the NMR derived both endo (³ J _H,H)- and exocyclic (³ JH,OH) coupling constants, nOe contacts and lineshape analyses of hydroxyl protons for EtpA (1), 3′-dA (2), rA (3), 2′-dA (4) [Fig. 1] in DMSO-d ₆ at 500 MHz.

MOLECULAR MODELLING OF 2′-OH MEDIATED HYDROGEN BONDING IN RIBONUCLEOS(T)IDES BY NMR CONSTRAINED AM1 AND MMX CALCULATIONS

All authors

Parag Acharya, Irina Velikian, Sandipta Acharya & Jyoti Chattopadhyaya

https://doi.org/10.1081/NCN-100002521

Published online:

07 February 2007

Figure 1. The schematic representation of the bias of the dymanic two-state pseudorotational equilibrium between the North-type (N, C2′-exo -C3′-endo) and the South-type (S, C3′-exo-C2′-endo) [3a] Thibaudeau, C. and Chattopadhyaya, J. 1999. Stereoelectronic Effects in Nucleosides and Nucleotides and their Structural Implications Sweden: (ISBN 91-506-1351-0), Department of Bioorganic Chemistry, Uppsala University Press (fax: +4618554495). For review see: and references therein [Google Scholar] pseudorotamers of the sugar moeity for EtpA (1), 3′-dA (2), rA (3), 2′-dA (4) and torsion (Φ) around C2′/3′-O bond viz. Φ₁ = Φ_{H2′?C2′?O?H} and Φ₂ = Φ_{H3′?C3′?O?H} except in 1 where the torsion across C3′-O3′ bond is actually ?^? [C4′-C3′-O3′-P].     

6.

Placement,survival and predator identity of Eurasian Curlew Numenius arquata nests on lowland grass-heath     

Natalia B. Zielonka  Robert W. Hawkes  Helen Jones  Robert J. Burnside  Paul M. Dolman 《Bird Study》2019,66(4):471-483

ABSTRACT

Capsule

Within the UK’s largest lowland Eurasian Curlew Numenius arquata population, curlew preferentially nested on physically disturbed (treated) than undisturbed (control) grassland, and low nest survival rates were primarily attributable to predation by Red Fox Vulpes vulpes.     

7.

Epichloë endophyte effects on leaf blotch pathogen (Rhynchosporium sp.) of tall fescue (Schedonorus phoenix) vary among grass origin and environmental conditions     

Miia Kauppinen  Marjo Helander  Noora Anttila  Irma Saloniemi  Kari Saikkonen 《Plant Ecology & Diversity》2018,11(5-6):625-635

ABSTRACT

Background

Systemic Epichloë endophytes are common fungal symbionts of many cool-season grasses. They are known for their capability of increasing host plant tolerance against biotic and abiotic stressors, including grass pathogens. However, results on endophyte-mediated disease resistance have been ambiguous, and the underlying mechanisms of disease resistance remain unknown.     

8.

A New Synthesis of 9-(2-Deoxy-2-fluoro-β-D-arabinofuranosyl)guanine (araF-G)     

《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1339-1342

Abstract

Interesting and very promising antisense properties of 2′-deoxy-2′-fluoroarabinonucleic acids ((a) Wilds, C.J.; Damha, M.J. 2′-Deoxy-2′-fluoroarabinonucleosides and oligonucleotides (2′F-ANA): synthesis and physicochemical studies. Nucl. Acids Res. 2000, 28, 3625–3635; (b) Viazovkina, E.; Mangos, M.; Elzagheid, M.I.; Damha, M.J. Current Protocols in Nucleic Acid Chemistry 2002, 4.15.1–4.15.21) (2′F-ANA) has encouraged our research group to optimize the synthetic procedures for 2′-deoxy-2′-fluoro-β-D-arabinonucleosides (araF-N). The synthesis of araF-U, araF-T, araF-A and araF-C is straightforward, (Tann, C.H.; Brodfuehrer, P.R.; Brundidge, S.P.; Sapino, C., Jr. Howell H.G. Fluorocarbohydrates in synthesis. An efficient synthesis of 1-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-5-iodouracil (β-FIAU) and 1-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)thymine (β-FMAU). J. Org. Chem. 1985, 50, 3644–3647; Howell, H.G.; Brodfuehrer, P.R.; Brundidge, S.P.; Benigni, D.A.; Sapino, C., Jr. Antiviral nucleosides. A stereospecific, total synthesis of 2′-fluoro-2′-deoxy-β-D-arabinofuranosyl nucleosides. J. Org. Chem. 1988, 53, 85–88; Maruyama, T.; Takamatsu, S.; Kozai, S.; Satoh, Y.; Izana, K. Synthesis of 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)adenine bearing a selectively removable protecting group. Chem. Pharm. Bull. 1999, 47, 966–970) however, the synthesis of the guanine analogue is more complicated and affords poor to moderate yields of araF-G (4) ((a) Elzagheid, M.I.; Viazovkina, E.; Masad, M.J. Synthesis of protected 2′-deoxy-2′-fluoro-β-D-arabinonucleosides. Synthesis of 2′-fluoroarabino nucleoside phosphoramidites and their use in the synthesis of 2′F-ANA. Current Protocols in Nucleic Acid Chemistry 2002, 1.7.1–1.7.19; (b) Tennila, T.; Azhayeva, E.; Vepsalainen, J.; Laatikainen, R.; Azhayev, A.; Mikhailopulo, I. Oligonucleotides containing 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-adenine and -guanine: synthesis, hybridization and antisense properties. Nucleosides, Nucleotides and Nucl. Acids 2000, 19, 1861–1884). Here we describe an efficient synthesis of araF-G (4) that involves coupling of 2-deoxy-2-fluoro-3,5-di-O-benzoyl-α-D- arabinofuranosyl bromide (1) with 2-chlorohypoxanthine (2) to afford 2-chloro-β-araF-I (3) in 52% yield. Nucleoside (3) was transformed into araF-G (4) by treatment with methanolic ammonia (150°C, 6 h) in 67% yield.     

9.

Syntheses of Several β-l-Rhamnopyranosides     

Shintaro Kamiya  Sachiko Esaki  Naoko Shiba 《Bioscience, biotechnology, and biochemistry》2013,77(8):2207-2214

To investigate the substrate specificity of β-l-rhamnosidase, the following β-l-rhamnopyranosides were synthesized: 1-(β-l-rhamnopyranosyl)-dl-glycerol (1), methyl β-l-rhamnopyranoside (2), methyl 2-O-(β-l-rhamnopyranosyl)-β-d-glucopyranoside (3) and methyl 2-O-β(β-l-rhamnopyranosyl)-α-l-arabinopyranoside (4). The synthesis of 3 was performed using l-quinovose with neighboring group participation, which lead stereoselectively to the β-l-quinovoside. The 2-OH of the l-quinovo-unit was selectively deblocked, oxidized to the keto group, and then stereoselectively reduced, whereby 3 was produced.     

10.

Il Pinus Mugo Turra Ed Il Pinus Uncinata Miller in Piemonte. Note Critiche e Distribuzione     

Franco Montacchini  Rosanna Caramiello 《Plant biosystems》2013,147(6):529-535

Abstract

«Pinus mugo» Turra and «Pinus uncinata» Miller in Piedmont. Critical notes and distribution. — The Authors have carried on a research on the distribution of Pinus mugo Turra (sensu Fl. Eur.) and Pinus uncinata Miller in all Piedmont Alpes and, having observed the extreme variability of the characters which are employed in the keys of determination to differentiate these two species, they suggest other and more constant characters. These are:

Il Pinus Mugo Turra Ed Il Pinus Uncinata Miller in Piemonte. Note Critiche e Distribuzione

All authors

Franco Montacchini & Rosanna Caramiello

https://doi.org/10.1080/11263506809426488

Published online:

14 September 2009

Table     

11.

Improved and Reliable Synthesis of 3′‐Azido‐2′,3′‐dideoxyguanosine Derivatives     

《Nucleosides, nucleotides & nucleic acids》2013,32(1-2):171-181

An improved synthesis of N²‐protected‐3′‐azido‐2′,3′‐dideoxyguanosine 20 and 23 is described. Deoxygenation of 2′‐O‐alkyl (and/or aryl) sulfonyl‐5′‐dimethoxytritylguanosine coupled with [1,2]‐hydride shift rearrangement gave protected 9‐(2‐deoxy‐threo‐pentofuranosyl)guanines ( 10 , 12 and 16 ). This rearrangement was accomplished in high yield with a high degree of stereoselectivity using lithium triisobutylborohydride (l‐Selectride®). Compounds 10 , 12 and 16 were transformed into 3′‐O‐mesylates ( 18 and 21 ), which can be used for 3′‐substitution. The 3′‐azido nucleosides were obtained by treatment of 18 and 21 with lithium azide. This procedure is reproducible with a good overall yield.     

12.

<Emphasis Type="Bold">Report from the 33rd</Emphasis><Emphasis Type="BoldItalic">Mycotoxin-Workshop</Emphasis><Emphasis Type="Bold">(Freising,Germany)</Emphasis>     

Karsten Meyer 《Mycotoxin Research》2011,27(4):303-306

Society for Mycotoxin Research – News and Announcements 2011/II

Report from the 33rd Mycotoxin-Workshop (Freising, Germany)     

13.

Synthetic Studies on the Isomeric N -Methyl Derivatives of C-Ribavirin     

Giin-Yuan Shen  Roland K. Robins  Ganapathi R. Revankar 《Nucleosides, nucleotides & nucleic acids》2013,32(8):1707-1717

Abstract

The syntheses of all three of the mono-N-methy1 derivatives of C-ribavirin (3-β-D-ribofuranosyl-1, 2, 4-triazole-5-carboxamide, 2) have been accomplished. Reaction of 1-(β-D-ribofuranosyliminomethyl)-2-methyl-hydrazine ( 7 ) with ethyl oxamate (8) in boiling ethanol gave the N′-methyl-C-ribavirin ( 3 ). A similar treatment of β-D-ribofuranosyl-1-carboximidic acid methyl ester ( 6 ) with N′-methyloxamic hydrazide ( 10 ) furnished the N²-methyl-C-ribavirin ( 4 ). Direct methylation of unprotected 2 with methyl iodide in the presence of potassium carbonate in dimethyl sulfoxide gave N ⁴-methyl isomer ( 5 ) as the major product. Structural assignments of 3 , 4 , and 5 were based on the unequivocal synthetic sequences, ¹H and ¹³C NMR data and confirmed by single crystal X-ray diffraction analysis.     

14.

Synthesis and Biological Evaluation of Some 5-Nitro- and 5-Amino Derivatives of 2′-Deoxycytidine, 2′,3′-Dideoxyuridine,and 2′,3′-Dideoxycytidine     

《Nucleosides, nucleotides & nucleic acids》2013,32(11):2013-2026

Abstract

In this article, we describe the synthesis of 5-nitro-1-(2-deoxy-α-D-erythro-pentofuranosyl)cytosine (4α), 5-nitro-1-(2-deoxy-β-D-erythro-pentofuranosyl)cytosine (4β), 5-amino-1-(2-deoxy-α-D-erythro-pentofuranosyl)cytosine (5α), 5-nitro-1- (2-deoxy-β-D-erythro-pentofuranosyl)cytosine (5β), 5-nitro-1-(2,3-dideoxy-β- D-ribofuranosyl)uracil (6β), 5-amino-1-(2,3-dideoxy-α,β-D-ribofuranosyl)uracil (7), 5-nitro-1-(2,3-dideoxy-α,β-D-ribofuranosyl)cytosine (8) and 5-amino-1-(2,3-dideoxy-β-D-ribofuranosyl)cytosine (9β). The prepared compounds were tested for their activity against HIV and HBV viruses, but they did not show significant activity.     

15.

Convenient Synthesis of 2′-Deoxy-2-fluoroadenosine from 2-Fluoroadenine     

《Nucleosides, nucleotides & nucleic acids》2013,32(10):1899-1905

Abstract

A convenient synthesis of 2′-deoxy-2-fluoroadenosine from commercially available 2-fluoroadenine is described. The coupling reaction of silylated 2-fluoroadenine with phenyl 3,5-bis[O-(t-butyldimethylsilyl)]-2-deoxy-1-thio-D-erythro-pentofuranoside gave the corresponding 2-fluoro-2′-deoxyadenosine derivative (α/β =1:1) in good yield. The α- and β-anomers were separated by chromatography, and then desilylated to give compounds 1a and 1b.     

16.

Chemo-enzymatic Synthesis of 3-Deoxy-β-D-ribofuranosyl Purines and Study of Their Biological Properties     

《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):751-753

Abstract

9-(3-Deoxy-β-d-erythro-pentofuranosyl)-2,6-diaminopurine (2) was synthesized by an enzymatic transglycosylation of 2,6-diaminopurine using 3′-deoxycytidine (1) as a donor of the sugar moiety. Nucleoside 2 was transformed to 3′-deoxy guanosine (3), 9-(3-deoxy-β-d-erythro-pentofuranosyl)-2-amino-6-oxopurine (3′-deoxyisoguanosine; 4), and 9-(3-deoxy-β-d-erythro-pentofuranosyl)-2-fluoroadenine (5). Compounds 2–5 were evaluated for their anti-HIV activity.     

17.

PHENYLALKYL BACKBONE MODIFIED OLIGODEOXYNUCLEOTIDES,THEIR SYNTHESIS AND THE INFLUENCE OF THE ALKYL CHAIN LENGTH     

《Nucleosides, nucleotides & nucleic acids》2013,32(4-7):1275-1278

Phenylalkyl modified phosphoramidites (alkyl chain length n = 1,2,3,5; Fig. 1) were synthesised and incorporated into a DNA hexamer (5′-d(GCCp-GCG); p = place of modification). The obtained diastereomeres were separated by RP-HPLC. After hybridisation with the complementary DNA strand T_m-value and thermodynamic data were measured. The stability of duplexes depends on the linker length and the absolute configuration of the backbone modified oligodeoxynucleotides (Rp, Sp).

PHENYLALKYL BACKBONE MODIFIED OLIGODEOXYNUCLEOTIDES, THEIR SYNTHESIS AND THE INFLUENCE OF THE ALKYL CHAIN LENGTH

All authors

Stefan Amberg & Joachim W. Engels

https://doi.org/10.1081/NCN-100002535

Published online:

07 February 2007

Figure 1. Structure of Rp- and Sp-configurated oligomers; synthesised phosphoramidites.     

18.

Isolation and characterization of Saccharomyces cerevisiae mutants supersensitive to G1 arrest by the mating hormone a-factor     

Martin Steden  Richard Betz  Wolfgang Duntze 《Molecular & general genetics : MGG》1989,219(3):439-444

Summary Nine independent mutants which are supersensitive (ssl ^–) to G1 arrest by the mating hormone a-factor were isolated by screening mutagenized Saccharomyces cerevisiae MAT cells on solid medium for increased growth inhibition with a-factor. These mutants carried lesions in two complementation groups, ssl1 and ssl2. Mutations at the ssl1 locus were mating type specific: MAT ssl1 ^– cells were supersensitive to -factor but MAT ssl1 ^– were not supersensitive to -factor. In contrast, mutations at the ssl2. locus conferred supersensitivity to the mating hormone of the opposite mating type on both MAT, and MATa cells. The -cell specific capacity to inactivate externally added a-factor was shown to be lacking in MAT ssl1 ^– mutants whereas MAT ssl2. cells were able to inactivate a-factor. Complementation analysis showed that ssl2 and sst2, a mutation originally isolated as conferring supersensitivity to -factor to MATa cells, are lesions in the same gene. The ssl1 gene was mapped 30.5 centi-Morgans distal to ilv5 on chromosome XII.     

19.

Oligonucleotides Containing Disaccharide Nucleosides: Synthesis,Physicochemical, and Substrate Properties     

《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1117-1118

Abstract

The efficient synthesis of oligonucleotides containing 2′-O-β-D-ribofuranosyl (and β-D-ribopyranosyl)nucleosides, 2′-O-α-D-arabinofuranosyl (and α-L-arabinofuranosyl)nucleosides, 2′-O-β-D-erythrofuranosylnucleosides, and 2′-O-(5′-amino-5-deoxy-β-D-ribofuranosyl)nucleosides have been developed.     

20.

A dominant mutation (SAD) bypassing the requirement for the a mating type locus in yeast sporulation     

Yona Kassir  Ira Herskowitz 《Molecular & general genetics : MGG》1980,180(2):315-322

Summary SAD (suppressor of a deficiencies) is a mutation that allows -mater diploids such as / or a1^-/ strains to sporulate. This mutation is unstable and reverts to wildtype (sad ⁺) even in strains homozygous for SAD. SAD is dominant to sad ⁺: / and a1^-/ sad ¹/SAD diploids are sporulation-proficient. SAD is located on chromosome III, 40 cM distal to the mating type locus, between THR4 and HMR a. The ability of SAD to support sporulation requires the presence of an mating type locus with an active 2 function. Possible models for the action of SAD are (1) SAD bypasses the need for a1 function in sporulation, and (2) SAD provides a1 function to MAT a1^- mutants by supplying a1 function itself, for example, by allowing expression of a silent copy of MAT a.     

Using water chemistry to define ecological preferences within the moss genus Scorpidium,from Wales,UK

ABSTRACT

Introduction

Three Scorpidium species: S. scorpioides, S. cossonii and S. revolvens are often associated with habitats of high conservation value. This is the first attempt to define the chemical niches for these Scorpidium species in Wales (UK) and allows us to compare these with earlier European datasets.     

Anthropogenic pressures within the breeding range of the Hen Harrier Circus cyaneus in Ireland

ABSTRACT

Capsule

Patterns in the frequency and co-occurrence of anthropogenic pressures associated with suitable breeding habitat for Hen Harriers Circus cyaneus demonstrates the need for specific, focussed management and policy options aimed at mitigating impacts on this threatened population.     

MOLECULAR MODELLING OF 2′-OH MEDIATED HYDROGEN BONDING IN RIBONUCLEOS(T)IDES BY NMR CONSTRAINED AM1 AND MMX CALCULATIONS

The intra- and intermolecular hydrogen bonding (ΔGº_298K ≈ 2, kcal mol^?1) of 2′-OH in nucleos(t)ides has been reported by the temperature- and concentration-dependent NMR study in conjunction with dihedral dependence of the NMR derived both endo (³ J _H,H)- and exocyclic (³ JH,OH) coupling constants, nOe contacts and lineshape analyses of hydroxyl protons for EtpA (1), 3′-dA (2), rA (3), 2′-dA (4) [Fig. 1] in DMSO-d ₆ at 500 MHz.

MOLECULAR MODELLING OF 2′-OH MEDIATED HYDROGEN BONDING IN RIBONUCLEOS(T)IDES BY NMR CONSTRAINED AM1 AND MMX CALCULATIONS

All authors

Parag Acharya, Irina Velikian, Sandipta Acharya & Jyoti Chattopadhyaya

https://doi.org/10.1081/NCN-100002521

Published online:

07 February 2007

Figure 1. The schematic representation of the bias of the dymanic two-state pseudorotational equilibrium between the North-type (N, C2′-exo -C3′-endo) and the South-type (S, C3′-exo-C2′-endo) [3a] Thibaudeau, C. and Chattopadhyaya, J. 1999. Stereoelectronic Effects in Nucleosides and Nucleotides and their Structural Implications Sweden: (ISBN 91-506-1351-0), Department of Bioorganic Chemistry, Uppsala University Press (fax: +4618554495). For review see: and references therein [Google Scholar] pseudorotamers of the sugar moeity for EtpA (1), 3′-dA (2), rA (3), 2′-dA (4) and torsion (Φ) around C2′/3′-O bond viz. Φ₁ = Φ_{H2′?C2′?O?H} and Φ₂ = Φ_{H3′?C3′?O?H} except in 1 where the torsion across C3′-O3′ bond is actually ?^? [C4′-C3′-O3′-P].     

6.

Placement,survival and predator identity of Eurasian Curlew Numenius arquata nests on lowland grass-heath     

Natalia B. Zielonka  Robert W. Hawkes  Helen Jones  Robert J. Burnside  Paul M. Dolman 《Bird Study》2019,66(4):471-483

ABSTRACT

Capsule

Within the UK’s largest lowland Eurasian Curlew Numenius arquata population, curlew preferentially nested on physically disturbed (treated) than undisturbed (control) grassland, and low nest survival rates were primarily attributable to predation by Red Fox Vulpes vulpes.     

7.

Epichloë endophyte effects on leaf blotch pathogen (Rhynchosporium sp.) of tall fescue (Schedonorus phoenix) vary among grass origin and environmental conditions     

Miia Kauppinen  Marjo Helander  Noora Anttila  Irma Saloniemi  Kari Saikkonen 《Plant Ecology & Diversity》2018,11(5-6):625-635

ABSTRACT

Background

Systemic Epichloë endophytes are common fungal symbionts of many cool-season grasses. They are known for their capability of increasing host plant tolerance against biotic and abiotic stressors, including grass pathogens. However, results on endophyte-mediated disease resistance have been ambiguous, and the underlying mechanisms of disease resistance remain unknown.     

8.

A New Synthesis of 9-(2-Deoxy-2-fluoro-β-D-arabinofuranosyl)guanine (araF-G)     

《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1339-1342

Abstract

Interesting and very promising antisense properties of 2′-deoxy-2′-fluoroarabinonucleic acids ((a) Wilds, C.J.; Damha, M.J. 2′-Deoxy-2′-fluoroarabinonucleosides and oligonucleotides (2′F-ANA): synthesis and physicochemical studies. Nucl. Acids Res. 2000, 28, 3625–3635; (b) Viazovkina, E.; Mangos, M.; Elzagheid, M.I.; Damha, M.J. Current Protocols in Nucleic Acid Chemistry 2002, 4.15.1–4.15.21) (2′F-ANA) has encouraged our research group to optimize the synthetic procedures for 2′-deoxy-2′-fluoro-β-D-arabinonucleosides (araF-N). The synthesis of araF-U, araF-T, araF-A and araF-C is straightforward, (Tann, C.H.; Brodfuehrer, P.R.; Brundidge, S.P.; Sapino, C., Jr. Howell H.G. Fluorocarbohydrates in synthesis. An efficient synthesis of 1-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-5-iodouracil (β-FIAU) and 1-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)thymine (β-FMAU). J. Org. Chem. 1985, 50, 3644–3647; Howell, H.G.; Brodfuehrer, P.R.; Brundidge, S.P.; Benigni, D.A.; Sapino, C., Jr. Antiviral nucleosides. A stereospecific, total synthesis of 2′-fluoro-2′-deoxy-β-D-arabinofuranosyl nucleosides. J. Org. Chem. 1988, 53, 85–88; Maruyama, T.; Takamatsu, S.; Kozai, S.; Satoh, Y.; Izana, K. Synthesis of 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)adenine bearing a selectively removable protecting group. Chem. Pharm. Bull. 1999, 47, 966–970) however, the synthesis of the guanine analogue is more complicated and affords poor to moderate yields of araF-G (4) ((a) Elzagheid, M.I.; Viazovkina, E.; Masad, M.J. Synthesis of protected 2′-deoxy-2′-fluoro-β-D-arabinonucleosides. Synthesis of 2′-fluoroarabino nucleoside phosphoramidites and their use in the synthesis of 2′F-ANA. Current Protocols in Nucleic Acid Chemistry 2002, 1.7.1–1.7.19; (b) Tennila, T.; Azhayeva, E.; Vepsalainen, J.; Laatikainen, R.; Azhayev, A.; Mikhailopulo, I. Oligonucleotides containing 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-adenine and -guanine: synthesis, hybridization and antisense properties. Nucleosides, Nucleotides and Nucl. Acids 2000, 19, 1861–1884). Here we describe an efficient synthesis of araF-G (4) that involves coupling of 2-deoxy-2-fluoro-3,5-di-O-benzoyl-α-D- arabinofuranosyl bromide (1) with 2-chlorohypoxanthine (2) to afford 2-chloro-β-araF-I (3) in 52% yield. Nucleoside (3) was transformed into araF-G (4) by treatment with methanolic ammonia (150°C, 6 h) in 67% yield.     

9.

Syntheses of Several β-l-Rhamnopyranosides     

Shintaro Kamiya  Sachiko Esaki  Naoko Shiba 《Bioscience, biotechnology, and biochemistry》2013,77(8):2207-2214

To investigate the substrate specificity of β-l-rhamnosidase, the following β-l-rhamnopyranosides were synthesized: 1-(β-l-rhamnopyranosyl)-dl-glycerol (1), methyl β-l-rhamnopyranoside (2), methyl 2-O-(β-l-rhamnopyranosyl)-β-d-glucopyranoside (3) and methyl 2-O-β(β-l-rhamnopyranosyl)-α-l-arabinopyranoside (4). The synthesis of 3 was performed using l-quinovose with neighboring group participation, which lead stereoselectively to the β-l-quinovoside. The 2-OH of the l-quinovo-unit was selectively deblocked, oxidized to the keto group, and then stereoselectively reduced, whereby 3 was produced.     

10.

Il Pinus Mugo Turra Ed Il Pinus Uncinata Miller in Piemonte. Note Critiche e Distribuzione     

Franco Montacchini  Rosanna Caramiello 《Plant biosystems》2013,147(6):529-535

Abstract

«Pinus mugo» Turra and «Pinus uncinata» Miller in Piedmont. Critical notes and distribution. — The Authors have carried on a research on the distribution of Pinus mugo Turra (sensu Fl. Eur.) and Pinus uncinata Miller in all Piedmont Alpes and, having observed the extreme variability of the characters which are employed in the keys of determination to differentiate these two species, they suggest other and more constant characters. These are:

Il Pinus Mugo Turra Ed Il Pinus Uncinata Miller in Piemonte. Note Critiche e Distribuzione

All authors

Franco Montacchini & Rosanna Caramiello

https://doi.org/10.1080/11263506809426488

Published online:

14 September 2009

Table     

11.

Improved and Reliable Synthesis of 3′‐Azido‐2′,3′‐dideoxyguanosine Derivatives     

《Nucleosides, nucleotides & nucleic acids》2013,32(1-2):171-181

An improved synthesis of N²‐protected‐3′‐azido‐2′,3′‐dideoxyguanosine 20 and 23 is described. Deoxygenation of 2′‐O‐alkyl (and/or aryl) sulfonyl‐5′‐dimethoxytritylguanosine coupled with [1,2]‐hydride shift rearrangement gave protected 9‐(2‐deoxy‐threo‐pentofuranosyl)guanines ( 10 , 12 and 16 ). This rearrangement was accomplished in high yield with a high degree of stereoselectivity using lithium triisobutylborohydride (l‐Selectride®). Compounds 10 , 12 and 16 were transformed into 3′‐O‐mesylates ( 18 and 21 ), which can be used for 3′‐substitution. The 3′‐azido nucleosides were obtained by treatment of 18 and 21 with lithium azide. This procedure is reproducible with a good overall yield.     

12.

<Emphasis Type="Bold">Report from the 33rd</Emphasis><Emphasis Type="BoldItalic">Mycotoxin-Workshop</Emphasis><Emphasis Type="Bold">(Freising,Germany)</Emphasis>     

Karsten Meyer 《Mycotoxin Research》2011,27(4):303-306

Society for Mycotoxin Research – News and Announcements 2011/II

Report from the 33rd Mycotoxin-Workshop (Freising, Germany)     

13.

Synthetic Studies on the Isomeric N -Methyl Derivatives of C-Ribavirin     

Giin-Yuan Shen  Roland K. Robins  Ganapathi R. Revankar 《Nucleosides, nucleotides & nucleic acids》2013,32(8):1707-1717

Abstract

The syntheses of all three of the mono-N-methy1 derivatives of C-ribavirin (3-β-D-ribofuranosyl-1, 2, 4-triazole-5-carboxamide, 2) have been accomplished. Reaction of 1-(β-D-ribofuranosyliminomethyl)-2-methyl-hydrazine ( 7 ) with ethyl oxamate (8) in boiling ethanol gave the N′-methyl-C-ribavirin ( 3 ). A similar treatment of β-D-ribofuranosyl-1-carboximidic acid methyl ester ( 6 ) with N′-methyloxamic hydrazide ( 10 ) furnished the N²-methyl-C-ribavirin ( 4 ). Direct methylation of unprotected 2 with methyl iodide in the presence of potassium carbonate in dimethyl sulfoxide gave N ⁴-methyl isomer ( 5 ) as the major product. Structural assignments of 3 , 4 , and 5 were based on the unequivocal synthetic sequences, ¹H and ¹³C NMR data and confirmed by single crystal X-ray diffraction analysis.     

14.

Synthesis and Biological Evaluation of Some 5-Nitro- and 5-Amino Derivatives of 2′-Deoxycytidine, 2′,3′-Dideoxyuridine,and 2′,3′-Dideoxycytidine     

《Nucleosides, nucleotides & nucleic acids》2013,32(11):2013-2026

Abstract

In this article, we describe the synthesis of 5-nitro-1-(2-deoxy-α-D-erythro-pentofuranosyl)cytosine (4α), 5-nitro-1-(2-deoxy-β-D-erythro-pentofuranosyl)cytosine (4β), 5-amino-1-(2-deoxy-α-D-erythro-pentofuranosyl)cytosine (5α), 5-nitro-1- (2-deoxy-β-D-erythro-pentofuranosyl)cytosine (5β), 5-nitro-1-(2,3-dideoxy-β- D-ribofuranosyl)uracil (6β), 5-amino-1-(2,3-dideoxy-α,β-D-ribofuranosyl)uracil (7), 5-nitro-1-(2,3-dideoxy-α,β-D-ribofuranosyl)cytosine (8) and 5-amino-1-(2,3-dideoxy-β-D-ribofuranosyl)cytosine (9β). The prepared compounds were tested for their activity against HIV and HBV viruses, but they did not show significant activity.     

15.

Convenient Synthesis of 2′-Deoxy-2-fluoroadenosine from 2-Fluoroadenine     

《Nucleosides, nucleotides & nucleic acids》2013,32(10):1899-1905

Abstract

A convenient synthesis of 2′-deoxy-2-fluoroadenosine from commercially available 2-fluoroadenine is described. The coupling reaction of silylated 2-fluoroadenine with phenyl 3,5-bis[O-(t-butyldimethylsilyl)]-2-deoxy-1-thio-D-erythro-pentofuranoside gave the corresponding 2-fluoro-2′-deoxyadenosine derivative (α/β =1:1) in good yield. The α- and β-anomers were separated by chromatography, and then desilylated to give compounds 1a and 1b.     

16.

Chemo-enzymatic Synthesis of 3-Deoxy-β-D-ribofuranosyl Purines and Study of Their Biological Properties     

《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):751-753

Abstract

9-(3-Deoxy-β-d-erythro-pentofuranosyl)-2,6-diaminopurine (2) was synthesized by an enzymatic transglycosylation of 2,6-diaminopurine using 3′-deoxycytidine (1) as a donor of the sugar moiety. Nucleoside 2 was transformed to 3′-deoxy guanosine (3), 9-(3-deoxy-β-d-erythro-pentofuranosyl)-2-amino-6-oxopurine (3′-deoxyisoguanosine; 4), and 9-(3-deoxy-β-d-erythro-pentofuranosyl)-2-fluoroadenine (5). Compounds 2–5 were evaluated for their anti-HIV activity.     

17.

PHENYLALKYL BACKBONE MODIFIED OLIGODEOXYNUCLEOTIDES,THEIR SYNTHESIS AND THE INFLUENCE OF THE ALKYL CHAIN LENGTH     

《Nucleosides, nucleotides & nucleic acids》2013,32(4-7):1275-1278

Phenylalkyl modified phosphoramidites (alkyl chain length n = 1,2,3,5; Fig. 1) were synthesised and incorporated into a DNA hexamer (5′-d(GCCp-GCG); p = place of modification). The obtained diastereomeres were separated by RP-HPLC. After hybridisation with the complementary DNA strand T_m-value and thermodynamic data were measured. The stability of duplexes depends on the linker length and the absolute configuration of the backbone modified oligodeoxynucleotides (Rp, Sp).

PHENYLALKYL BACKBONE MODIFIED OLIGODEOXYNUCLEOTIDES, THEIR SYNTHESIS AND THE INFLUENCE OF THE ALKYL CHAIN LENGTH

All authors

Stefan Amberg & Joachim W. Engels

https://doi.org/10.1081/NCN-100002535

Published online:

07 February 2007

Figure 1. Structure of Rp- and Sp-configurated oligomers; synthesised phosphoramidites.     

18.

Isolation and characterization of Saccharomyces cerevisiae mutants supersensitive to G1 arrest by the mating hormone a-factor     

Martin Steden  Richard Betz  Wolfgang Duntze 《Molecular & general genetics : MGG》1989,219(3):439-444

Summary Nine independent mutants which are supersensitive (ssl ^–) to G1 arrest by the mating hormone a-factor were isolated by screening mutagenized Saccharomyces cerevisiae MAT cells on solid medium for increased growth inhibition with a-factor. These mutants carried lesions in two complementation groups, ssl1 and ssl2. Mutations at the ssl1 locus were mating type specific: MAT ssl1 ^– cells were supersensitive to -factor but MAT ssl1 ^– were not supersensitive to -factor. In contrast, mutations at the ssl2. locus conferred supersensitivity to the mating hormone of the opposite mating type on both MAT, and MATa cells. The -cell specific capacity to inactivate externally added a-factor was shown to be lacking in MAT ssl1 ^– mutants whereas MAT ssl2. cells were able to inactivate a-factor. Complementation analysis showed that ssl2 and sst2, a mutation originally isolated as conferring supersensitivity to -factor to MATa cells, are lesions in the same gene. The ssl1 gene was mapped 30.5 centi-Morgans distal to ilv5 on chromosome XII.     

19.

Oligonucleotides Containing Disaccharide Nucleosides: Synthesis,Physicochemical, and Substrate Properties     

《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1117-1118

Abstract

The efficient synthesis of oligonucleotides containing 2′-O-β-D-ribofuranosyl (and β-D-ribopyranosyl)nucleosides, 2′-O-α-D-arabinofuranosyl (and α-L-arabinofuranosyl)nucleosides, 2′-O-β-D-erythrofuranosylnucleosides, and 2′-O-(5′-amino-5-deoxy-β-D-ribofuranosyl)nucleosides have been developed.     

20.

A dominant mutation (SAD) bypassing the requirement for the a mating type locus in yeast sporulation     

Yona Kassir  Ira Herskowitz 《Molecular & general genetics : MGG》1980,180(2):315-322

Summary SAD (suppressor of a deficiencies) is a mutation that allows -mater diploids such as / or a1^-/ strains to sporulate. This mutation is unstable and reverts to wildtype (sad ⁺) even in strains homozygous for SAD. SAD is dominant to sad ⁺: / and a1^-/ sad ¹/SAD diploids are sporulation-proficient. SAD is located on chromosome III, 40 cM distal to the mating type locus, between THR4 and HMR a. The ability of SAD to support sporulation requires the presence of an mating type locus with an active 2 function. Possible models for the action of SAD are (1) SAD bypasses the need for a1 function in sporulation, and (2) SAD provides a1 function to MAT a1^- mutants by supplying a1 function itself, for example, by allowing expression of a silent copy of MAT a.     

Placement,survival and predator identity of Eurasian Curlew Numenius arquata nests on lowland grass-heath

ABSTRACT

Capsule

Within the UK’s largest lowland Eurasian Curlew Numenius arquata population, curlew preferentially nested on physically disturbed (treated) than undisturbed (control) grassland, and low nest survival rates were primarily attributable to predation by Red Fox Vulpes vulpes.     

Epichloë endophyte effects on leaf blotch pathogen (Rhynchosporium sp.) of tall fescue (Schedonorus phoenix) vary among grass origin and environmental conditions

ABSTRACT

Background

Systemic Epichloë endophytes are common fungal symbionts of many cool-season grasses. They are known for their capability of increasing host plant tolerance against biotic and abiotic stressors, including grass pathogens. However, results on endophyte-mediated disease resistance have been ambiguous, and the underlying mechanisms of disease resistance remain unknown.     

A New Synthesis of 9-(2-Deoxy-2-fluoro-β-D-arabinofuranosyl)guanine (araF-G)

Abstract

Interesting and very promising antisense properties of 2′-deoxy-2′-fluoroarabinonucleic acids ((a) Wilds, C.J.; Damha, M.J. 2′-Deoxy-2′-fluoroarabinonucleosides and oligonucleotides (2′F-ANA): synthesis and physicochemical studies. Nucl. Acids Res. 2000, 28, 3625–3635; (b) Viazovkina, E.; Mangos, M.; Elzagheid, M.I.; Damha, M.J. Current Protocols in Nucleic Acid Chemistry 2002, 4.15.1–4.15.21) (2′F-ANA) has encouraged our research group to optimize the synthetic procedures for 2′-deoxy-2′-fluoro-β-D-arabinonucleosides (araF-N). The synthesis of araF-U, araF-T, araF-A and araF-C is straightforward, (Tann, C.H.; Brodfuehrer, P.R.; Brundidge, S.P.; Sapino, C., Jr. Howell H.G. Fluorocarbohydrates in synthesis. An efficient synthesis of 1-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-5-iodouracil (β-FIAU) and 1-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)thymine (β-FMAU). J. Org. Chem. 1985, 50, 3644–3647; Howell, H.G.; Brodfuehrer, P.R.; Brundidge, S.P.; Benigni, D.A.; Sapino, C., Jr. Antiviral nucleosides. A stereospecific, total synthesis of 2′-fluoro-2′-deoxy-β-D-arabinofuranosyl nucleosides. J. Org. Chem. 1988, 53, 85–88; Maruyama, T.; Takamatsu, S.; Kozai, S.; Satoh, Y.; Izana, K. Synthesis of 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)adenine bearing a selectively removable protecting group. Chem. Pharm. Bull. 1999, 47, 966–970) however, the synthesis of the guanine analogue is more complicated and affords poor to moderate yields of araF-G (4) ((a) Elzagheid, M.I.; Viazovkina, E.; Masad, M.J. Synthesis of protected 2′-deoxy-2′-fluoro-β-D-arabinonucleosides. Synthesis of 2′-fluoroarabino nucleoside phosphoramidites and their use in the synthesis of 2′F-ANA. Current Protocols in Nucleic Acid Chemistry 2002, 1.7.1–1.7.19; (b) Tennila, T.; Azhayeva, E.; Vepsalainen, J.; Laatikainen, R.; Azhayev, A.; Mikhailopulo, I. Oligonucleotides containing 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-adenine and -guanine: synthesis, hybridization and antisense properties. Nucleosides, Nucleotides and Nucl. Acids 2000, 19, 1861–1884). Here we describe an efficient synthesis of araF-G (4) that involves coupling of 2-deoxy-2-fluoro-3,5-di-O-benzoyl-α-D- arabinofuranosyl bromide (1) with 2-chlorohypoxanthine (2) to afford 2-chloro-β-araF-I (3) in 52% yield. Nucleoside (3) was transformed into araF-G (4) by treatment with methanolic ammonia (150°C, 6 h) in 67% yield.     

Syntheses of Several β-l-Rhamnopyranosides

To investigate the substrate specificity of β-l-rhamnosidase, the following β-l-rhamnopyranosides were synthesized: 1-(β-l-rhamnopyranosyl)-dl-glycerol (1), methyl β-l-rhamnopyranoside (2), methyl 2-O-(β-l-rhamnopyranosyl)-β-d-glucopyranoside (3) and methyl 2-O-β(β-l-rhamnopyranosyl)-α-l-arabinopyranoside (4). The synthesis of 3 was performed using l-quinovose with neighboring group participation, which lead stereoselectively to the β-l-quinovoside. The 2-OH of the l-quinovo-unit was selectively deblocked, oxidized to the keto group, and then stereoselectively reduced, whereby 3 was produced.     

Il Pinus Mugo Turra Ed Il Pinus Uncinata Miller in Piemonte. Note Critiche e Distribuzione

Abstract

«Pinus mugo» Turra and «Pinus uncinata» Miller in Piedmont. Critical notes and distribution. — The Authors have carried on a research on the distribution of Pinus mugo Turra (sensu Fl. Eur.) and Pinus uncinata Miller in all Piedmont Alpes and, having observed the extreme variability of the characters which are employed in the keys of determination to differentiate these two species, they suggest other and more constant characters. These are:

Il Pinus Mugo Turra Ed Il Pinus Uncinata Miller in Piemonte. Note Critiche e Distribuzione

All authors

Franco Montacchini & Rosanna Caramiello

https://doi.org/10.1080/11263506809426488

Published online:

14 September 2009

Table     

Improved and Reliable Synthesis of 3′‐Azido‐2′,3′‐dideoxyguanosine Derivatives

An improved synthesis of N²‐protected‐3′‐azido‐2′,3′‐dideoxyguanosine 20 and 23 is described. Deoxygenation of 2′‐O‐alkyl (and/or aryl) sulfonyl‐5′‐dimethoxytritylguanosine coupled with [1,2]‐hydride shift rearrangement gave protected 9‐(2‐deoxy‐threo‐pentofuranosyl)guanines ( 10 , 12 and 16 ). This rearrangement was accomplished in high yield with a high degree of stereoselectivity using lithium triisobutylborohydride (l‐Selectride®). Compounds 10 , 12 and 16 were transformed into 3′‐O‐mesylates ( 18 and 21 ), which can be used for 3′‐substitution. The 3′‐azido nucleosides were obtained by treatment of 18 and 21 with lithium azide. This procedure is reproducible with a good overall yield.     

<Emphasis Type="Bold">Report from the 33rd</Emphasis><Emphasis Type="BoldItalic">Mycotoxin-Workshop</Emphasis><Emphasis Type="Bold">(Freising,Germany)</Emphasis>

Society for Mycotoxin Research – News and Announcements 2011/II

Report from the 33rd Mycotoxin-Workshop (Freising, Germany)     

Synthetic Studies on the Isomeric N -Methyl Derivatives of C-Ribavirin

Abstract

The syntheses of all three of the mono-N-methy1 derivatives of C-ribavirin (3-β-D-ribofuranosyl-1, 2, 4-triazole-5-carboxamide, 2) have been accomplished. Reaction of 1-(β-D-ribofuranosyliminomethyl)-2-methyl-hydrazine ( 7 ) with ethyl oxamate (8) in boiling ethanol gave the N′-methyl-C-ribavirin ( 3 ). A similar treatment of β-D-ribofuranosyl-1-carboximidic acid methyl ester ( 6 ) with N′-methyloxamic hydrazide ( 10 ) furnished the N²-methyl-C-ribavirin ( 4 ). Direct methylation of unprotected 2 with methyl iodide in the presence of potassium carbonate in dimethyl sulfoxide gave N ⁴-methyl isomer ( 5 ) as the major product. Structural assignments of 3 , 4 , and 5 were based on the unequivocal synthetic sequences, ¹H and ¹³C NMR data and confirmed by single crystal X-ray diffraction analysis.     

Synthesis and Biological Evaluation of Some 5-Nitro- and 5-Amino Derivatives of 2′-Deoxycytidine, 2′,3′-Dideoxyuridine,and 2′,3′-Dideoxycytidine

Abstract

In this article, we describe the synthesis of 5-nitro-1-(2-deoxy-α-D-erythro-pentofuranosyl)cytosine (4α), 5-nitro-1-(2-deoxy-β-D-erythro-pentofuranosyl)cytosine (4β), 5-amino-1-(2-deoxy-α-D-erythro-pentofuranosyl)cytosine (5α), 5-nitro-1- (2-deoxy-β-D-erythro-pentofuranosyl)cytosine (5β), 5-nitro-1-(2,3-dideoxy-β- D-ribofuranosyl)uracil (6β), 5-amino-1-(2,3-dideoxy-α,β-D-ribofuranosyl)uracil (7), 5-nitro-1-(2,3-dideoxy-α,β-D-ribofuranosyl)cytosine (8) and 5-amino-1-(2,3-dideoxy-β-D-ribofuranosyl)cytosine (9β). The prepared compounds were tested for their activity against HIV and HBV viruses, but they did not show significant activity.     

Convenient Synthesis of 2′-Deoxy-2-fluoroadenosine from 2-Fluoroadenine

Abstract

A convenient synthesis of 2′-deoxy-2-fluoroadenosine from commercially available 2-fluoroadenine is described. The coupling reaction of silylated 2-fluoroadenine with phenyl 3,5-bis[O-(t-butyldimethylsilyl)]-2-deoxy-1-thio-D-erythro-pentofuranoside gave the corresponding 2-fluoro-2′-deoxyadenosine derivative (α/β =1:1) in good yield. The α- and β-anomers were separated by chromatography, and then desilylated to give compounds 1a and 1b.     

Chemo-enzymatic Synthesis of 3-Deoxy-β-D-ribofuranosyl Purines and Study of Their Biological Properties

Abstract

9-(3-Deoxy-β-d-erythro-pentofuranosyl)-2,6-diaminopurine (2) was synthesized by an enzymatic transglycosylation of 2,6-diaminopurine using 3′-deoxycytidine (1) as a donor of the sugar moiety. Nucleoside 2 was transformed to 3′-deoxy guanosine (3), 9-(3-deoxy-β-d-erythro-pentofuranosyl)-2-amino-6-oxopurine (3′-deoxyisoguanosine; 4), and 9-(3-deoxy-β-d-erythro-pentofuranosyl)-2-fluoroadenine (5). Compounds 2–5 were evaluated for their anti-HIV activity.     

PHENYLALKYL BACKBONE MODIFIED OLIGODEOXYNUCLEOTIDES,THEIR SYNTHESIS AND THE INFLUENCE OF THE ALKYL CHAIN LENGTH

Phenylalkyl modified phosphoramidites (alkyl chain length n = 1,2,3,5; Fig. 1) were synthesised and incorporated into a DNA hexamer (5′-d(GCCp-GCG); p = place of modification). The obtained diastereomeres were separated by RP-HPLC. After hybridisation with the complementary DNA strand T_m-value and thermodynamic data were measured. The stability of duplexes depends on the linker length and the absolute configuration of the backbone modified oligodeoxynucleotides (Rp, Sp).

PHENYLALKYL BACKBONE MODIFIED OLIGODEOXYNUCLEOTIDES, THEIR SYNTHESIS AND THE INFLUENCE OF THE ALKYL CHAIN LENGTH

All authors

Stefan Amberg & Joachim W. Engels

https://doi.org/10.1081/NCN-100002535

Published online:

07 February 2007

Figure 1. Structure of Rp- and Sp-configurated oligomers; synthesised phosphoramidites.     

18.

Isolation and characterization of Saccharomyces cerevisiae mutants supersensitive to G1 arrest by the mating hormone a-factor     

Martin Steden  Richard Betz  Wolfgang Duntze 《Molecular & general genetics : MGG》1989,219(3):439-444

Summary Nine independent mutants which are supersensitive (ssl ^–) to G1 arrest by the mating hormone a-factor were isolated by screening mutagenized Saccharomyces cerevisiae MAT cells on solid medium for increased growth inhibition with a-factor. These mutants carried lesions in two complementation groups, ssl1 and ssl2. Mutations at the ssl1 locus were mating type specific: MAT ssl1 ^– cells were supersensitive to -factor but MAT ssl1 ^– were not supersensitive to -factor. In contrast, mutations at the ssl2. locus conferred supersensitivity to the mating hormone of the opposite mating type on both MAT, and MATa cells. The -cell specific capacity to inactivate externally added a-factor was shown to be lacking in MAT ssl1 ^– mutants whereas MAT ssl2. cells were able to inactivate a-factor. Complementation analysis showed that ssl2 and sst2, a mutation originally isolated as conferring supersensitivity to -factor to MATa cells, are lesions in the same gene. The ssl1 gene was mapped 30.5 centi-Morgans distal to ilv5 on chromosome XII.     

19.

Oligonucleotides Containing Disaccharide Nucleosides: Synthesis,Physicochemical, and Substrate Properties     

《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1117-1118

Abstract

The efficient synthesis of oligonucleotides containing 2′-O-β-D-ribofuranosyl (and β-D-ribopyranosyl)nucleosides, 2′-O-α-D-arabinofuranosyl (and α-L-arabinofuranosyl)nucleosides, 2′-O-β-D-erythrofuranosylnucleosides, and 2′-O-(5′-amino-5-deoxy-β-D-ribofuranosyl)nucleosides have been developed.     

20.

A dominant mutation (SAD) bypassing the requirement for the a mating type locus in yeast sporulation     

Yona Kassir  Ira Herskowitz 《Molecular & general genetics : MGG》1980,180(2):315-322

Summary SAD (suppressor of a deficiencies) is a mutation that allows -mater diploids such as / or a1^-/ strains to sporulate. This mutation is unstable and reverts to wildtype (sad ⁺) even in strains homozygous for SAD. SAD is dominant to sad ⁺: / and a1^-/ sad ¹/SAD diploids are sporulation-proficient. SAD is located on chromosome III, 40 cM distal to the mating type locus, between THR4 and HMR a. The ability of SAD to support sporulation requires the presence of an mating type locus with an active 2 function. Possible models for the action of SAD are (1) SAD bypasses the need for a1 function in sporulation, and (2) SAD provides a1 function to MAT a1^- mutants by supplying a1 function itself, for example, by allowing expression of a silent copy of MAT a.     

Isolation and characterization of Saccharomyces cerevisiae mutants supersensitive to G1 arrest by the mating hormone a-factor

Summary Nine independent mutants which are supersensitive (ssl ^–) to G1 arrest by the mating hormone a-factor were isolated by screening mutagenized Saccharomyces cerevisiae MAT cells on solid medium for increased growth inhibition with a-factor. These mutants carried lesions in two complementation groups, ssl1 and ssl2. Mutations at the ssl1 locus were mating type specific: MAT ssl1 ^– cells were supersensitive to -factor but MAT ssl1 ^– were not supersensitive to -factor. In contrast, mutations at the ssl2. locus conferred supersensitivity to the mating hormone of the opposite mating type on both MAT, and MATa cells. The -cell specific capacity to inactivate externally added a-factor was shown to be lacking in MAT ssl1 ^– mutants whereas MAT ssl2. cells were able to inactivate a-factor. Complementation analysis showed that ssl2 and sst2, a mutation originally isolated as conferring supersensitivity to -factor to MATa cells, are lesions in the same gene. The ssl1 gene was mapped 30.5 centi-Morgans distal to ilv5 on chromosome XII.     

Oligonucleotides Containing Disaccharide Nucleosides: Synthesis,Physicochemical, and Substrate Properties

Abstract

The efficient synthesis of oligonucleotides containing 2′-O-β-D-ribofuranosyl (and β-D-ribopyranosyl)nucleosides, 2′-O-α-D-arabinofuranosyl (and α-L-arabinofuranosyl)nucleosides, 2′-O-β-D-erythrofuranosylnucleosides, and 2′-O-(5′-amino-5-deoxy-β-D-ribofuranosyl)nucleosides have been developed.     

A dominant mutation (SAD) bypassing the requirement for the a mating type locus in yeast sporulation

Summary SAD (suppressor of a deficiencies) is a mutation that allows -mater diploids such as / or a1^-/ strains to sporulate. This mutation is unstable and reverts to wildtype (sad ⁺) even in strains homozygous for SAD. SAD is dominant to sad ⁺: / and a1^-/ sad ¹/SAD diploids are sporulation-proficient. SAD is located on chromosome III, 40 cM distal to the mating type locus, between THR4 and HMR a. The ability of SAD to support sporulation requires the presence of an mating type locus with an active 2 function. Possible models for the action of SAD are (1) SAD bypasses the need for a1 function in sporulation, and (2) SAD provides a1 function to MAT a1^- mutants by supplying a1 function itself, for example, by allowing expression of a silent copy of MAT a.