Synthesis of dinucleoside acylphosphonites by phosphonodiamidite chemistry and investigation of phosphorus epimerization

• William H. Hersh

Beilstein J. Org. Chem. 2015, 11, 184–191, doi:10.3762/bjoc.11.19

• corresponding acyl diamidites, RC(O)P(N(iPr)2)2 (R = Me (7), Ph (9)), without the intervention of sodium to give a phosphorus anion. The structure of 9 was confirmed by single-crystal X-ray diffraction. The coupling of the diamidites 7 and 9 with 5′-O-DMTr-thymidine was carried out with N-methylimidazolium

• triflate as the activator to give the monoamidites 3′-O-(P(N(iPr)2)C(O)R)-5′-O-DMTr-thymidine, and further coupling with 3′-O-(tert-butyldimethylsilyl)thymidine was carried out with activation by pyridinium trifluoroacetate/N-methylimidazole. The new dinucleoside acylphosphonites could be further oxidized

• lone pair orbitals. However, as noted above, this does not result in an amide-like 13C chemical shift. Nucleoside coupling. The initial attempts at coupling 7 and 9 with 5′-O-DMTr-thymidine were carried out using the Caruthers procedure with 4,5-dicyanoimidazole (DCI) as the activator. While formation

NAA-modified DNA oligonucleotides with zwitterionic backbones: stereoselective synthesis of A–T phosphoramidite building blocks

• Boris Schmidtgall,
• Claudia Höbartner and
• Christian Ducho

Beilstein J. Org. Chem. 2015, 11, 50–60, doi:10.3762/bjoc.11.8

• envisioned that target compounds (S)-7 and (R)-7 could be obtained from protected 3'-amino-2',3'-dideoxyadenosine 8 and the N-Fmoc-protected thymidine-derived nucleosyl amino acids (S)-9 and (R)-9, respectively, via amide coupling, protecting group manipulation and phosphitylation. The stereoselective

• synthesis of both 6'-epimers of nucleosyl amino acid 9 has been reported before. We have used 3-(N-BOM)-protected thymidine-5'-aldehyde 10 (BOM = benzyloxymethyl), which can readily be obtained from thymidine, in a sequence of Wittig–Horner reaction, asymmetric hydrogenation of the resultant didehydro

• corresponding uridine-derived nucleosyl amino acids, we have found that uracil protection was not advantageous for the aforementioned reaction sequence [48]. We have therefore decided to employ both the 3-(N-BOM)-protected thymidine-5'-aldehyde 10 and also its thymine-unprotected congener 11 in Wittig–Horner

Pyrrolidine nucleotide analogs with a tunable conformation

• Lenka Poštová Slavětínská,
• Dominik Rejman and
• Radek Pohl

Beilstein J. Org. Chem. 2014, 10, 1967–1980, doi:10.3762/bjoc.10.205

• ) – inhibitors of thymidine phosphorylase isolated from spontaneous lymphoma of SD rats (IC50 = 15 and 11 nM, respectively) [4], guanine derivative 5 – a potent inhibitor of human purine nucleoside phosphorylase PNP (Ki = 10 nM) [5], and finally guanine derivative 6 – exhibiting inhibitory activity against 6

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• precursors to a variety of compounds. The transformations leading to thymidine or its derivatives 3 involved: (a) the metal-catalyzed hydrogenolysis of products 2 [51][52][54][55] (or their 5-(4-tolylthio)methyl derivatives [57]), or (b) the reduction of methylammonium iodides derived from compounds 2 with

• the addition of the nucleoside moiety to the C-1 or C-2 carbon atom of the C=C double bond. The three-component reactions of nucleoside-derived (uridine or thymidine) allenes 97, a range of aryl iodides, and 1-adamantylamine was accomplished smoothly under the palladium-catalyzed conditions (Scheme 40

The chemoenzymatic synthesis of clofarabine and related 2′-deoxyfluoroarabinosyl nucleosides: the electronic and stereochemical factors determining substrate recognition by E. coli nucleoside phosphorylases

• Ilja V. Fateev,
• Konstantin V. Antonov,
• Irina D. Konstantinova,
• Tatyana I. Muravyova,
• Frank Seela,
• Roman S. Esipov,
• Anatoly I. Miroshnikov and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2014, 10, 1657–1669, doi:10.3762/bjoc.10.173

• residue of FMAU was realized by the concerted action of E. coli thymidine phosphorylase (TP) absorbed on DEAE cellulose for the intermediary generation of the phosphate 12a and E. coli purine nucleoside phosphorylase (PNP) for the condensation of the latter with bases. The two most challenging features of

Human dendritic cell activation induced by a permannosylated dendron containing an antigenic GM₃-lactone mimetic

• Renato Ribeiro-Viana,
• Elena Bonechi,
• Javier Rojo,
• Clara Ballerini,
• Giuseppina Comito,
• Barbara Richichi and
• Cristina Nativi

Beilstein J. Org. Chem. 2014, 10, 1317–1324, doi:10.3762/bjoc.10.133

• bottom plates (Nunc). 1 × 105 CD4+ T cells were incubated for 5 days in RPMI with 10% FCS together with 1 × 104 to 1 × 103 allogeneic DCs. Experiments were conducted in quadruplicate. At day 5, the proliferative response was measured by the [3H]-thymidine ([3H]-Thy, 1 µCi/mL, Amersham) incorporation test

A new building block for DNA network formation by self-assembly and polymerase chain reaction

• Holger Bußkamp,
• Sascha Keller,
• Marta Robotta,
• Malte Drescher and
• Andreas Marx

Beilstein J. Org. Chem. 2014, 10, 1037–1046, doi:10.3762/bjoc.10.104

• duplex formation properties. In order to investigate whether the thymidine residues that are directly linked to the benzene core are amenable to participate in duplex formation, complementary oligonucleotides with varied lengths were investigated and compared to linear, non-branched reference duplexes

• terminal thymidine that is covalently connected to the benzene core via a rigid ethylene bridge is amenable to contribute to duplex stability. This was evidenced by an increase in Tm, when ODN I was hybridized to 10 in comparison to the one nucleotide shorter 9. Next, bDNA constructs were characterized by

Damage of polyesters by the atmospheric free radical oxidant NO₃^•: a product study involving model systems

• Catrin Goeschen and
• Uta Wille

Beilstein J. Org. Chem. 2013, 9, 1907–1916, doi:10.3762/bjoc.9.225

• ratio towards the nitrate 4 at expense of the higher oxidized products 5 and 6 (data not shown). The observed side-chain oxidation in 3 by NO3• is similar to the outcome of the reaction of thymidine nucleosides with NO3•, where oxidative transformation of the methyl substituent in the heterocyclic base

An easily accessible sulfated saccharide mimetic inhibits in vitro human tumor cell adhesion and angiogenesis of vascular endothelial cells

• Grazia Marano,
• Claas Gronewold,
• Martin Frank,
• Anette Merling,
• Christian Kliem,
• Sandra Sauer,
• Manfred Wiessler,
• Eva Frei and
• Reinhard Schwartz-Albiez

Beilstein J. Org. Chem. 2012, 8, 787–803, doi:10.3762/bjoc.8.89

• labeled with [methyl-3H]-thymidine and we found a linear relation between the incorporated radioactivity and the number of cells, between 1 × 104 and 7 × 104 cells. To find the optimal conditions for WM-115 cells, their adhesion to increasing amounts of fibrinogen and fibronectin from 0.1–2 µg per well

• labeled with [methyl-3H]-thymidine (spec. activity 1.16–31.5 TBq/mmol, Hartmann Analytic, Braunschweig, Germany), 1.48 MBq/106 cells/mL and incubated for 16 h at their respective temperatures. Cells were detached with 0.05% EDTA and washed three times in assay-medium (serum-free MEM-medium with Earle’s

Synthesis, reactivity and biological activity of 5-alkoxymethyluracil analogues

• Lucie Brulikova and
• Jan Hlavac

Beilstein J. Org. Chem. 2011, 7, 678–698, doi:10.3762/bjoc.7.80

• interest since the early 1970s due to their potential chemotherapeutic and antiviral properties. It was reported, for instance, that 5-ethyluracil may undergo incorporation into bacterial DNA [25] and that 5-ethyl-2'-deoxyuridine readily replaces thymidine in bacteriophage DNA [26]. Bergstrom and co

• oligonucleotide chemistry associated with this review is focused on the studies of the action of 5-formyl-2'-deoxyuridine, which is one of the oxidative thymidine lesions of DNA formed by ionizing radiation. Consequently, several methods for the preparation of appropriate intermediates for the synthesis of

• interaction between the above noted proteins and modified oligonucleotides, in which thymidine is replaced by a 5-formyl derivative. A phosphoramidite 145 for oligonucleotide synthesis was prepared from O2-2'-cyclouridine (135) by a multistep synthesis (Scheme 24). In a first step, O2-2'-cyclouridine (135

A novel and efficient method to prepare 2-aryltetrahydrofuran-2-ylphosphonic acids

• Vsevolod V. Komissarov,
• Anatoly M. Kritzyn and
• Jouko J. Vepsäläinen

Beilstein J. Org. Chem. 2010, 6, No. 63, doi:10.3762/bjoc.6.63

• phosphorylase and thymidine phosphorylase, enzymes which have been targeted in a number of serious diseases [5][6][7]. Recently, we prepared nucleic base derivatives with a terminal Ph-CO-group by alkylation methods starting from 4-chloro-1-aryl-1-butanones 1 [8]. According to the studies of Conant et al. [9

The first salen- type ligands derived from 3',5'-diamino- 3',5'-dideoxythymidine and -dideoxyxylothymidine and their corresponding copper(II) complexes

• Daniel Koth,
• Michael Gottschaldt,
• Helmar Görls and
• Karolin Pohle

Beilstein J. Org. Chem. 2006, 2, No. 17, doi:10.1186/1860-5397-2-17

• as xylo-configuration and the preparation of copper(II) complexes derived from their corresponding Schiff bases. Starting from thymidine, the amino derivatives were prepared in a three and four step reaction sequence respectively. The absolute configuration of the ligands was proved by the three-bond

• -isomer 3 itself has only been described once as a by-product, whose analytical characterization we found had been given insufficiently. [9] Starting with commercially supplied thymidine, and using methanesulfonyl chloride in pyridine, compound 2 was obtained in a yield of 86%. Nucleophilic substitution

• reaction time led to the desired 3',5'-diamino-3',5'-dideoxy-β-D-xylo-thymidine 6 in 90% yield. Although this compound is easy to synthesize, it has not been described yet. Subsequent condensation of 6 and 7 with salicylic aldehyde provides compounds 8–11 as crystalline solids. The Schiff bases 8–11 of the