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

• -arabinofuranose (9) into the phosphate 12a without isolation of intermediary products. Condensation of 12a with 2-chloroadenine catalyzed by the recombinant E. coli purine nucleoside phosphorylase (PNP) resulted in the formation of clofarabine in 67% yield. The reaction was also studied with a number of purine

• ; Introduction Pyrimidine and purine 2-deoxy-2-fluoro-β-D-arabinofuranosides demonstrate a broad spectrum of biological activity [1][2][3][4][5][6][7][8][9] and are valuable constituents of artificial oligonucleotides of great molecular biological and medicinal potential [10][11]. Among this family of

• conclusion that the search for novel more efficient “green” methods is of reasonable interest. In this context, the study by Yamada et al. on the chemical synthesis of 2-deoxy-2-fluoro-α-D-arabinofuranose-1-phosphate (12a; 2FAra-1P) and its use in an enzymatic coupling with purine bases is of great interest

Pyrene-modified PNAs: Stacking interactions and selective excimer emission in PNA₂DNA triplexes

• Alex Manicardi,
• Lucia Guidi,
• Alice Ghidini and
• Roberto Corradini

Beilstein J. Org. Chem. 2014, 10, 1495–1503, doi:10.3762/bjoc.10.154

• stable triplexes of the type PNA/DNA/PNA with poly-purine DNA, via both Watson–Crick and Hoogsteen base pairing (Figure 1). These structures are so stable that dsDNA undergoes displacement of the non-complementary strand [4][5][6][7]. However, the formation of triplex structures is limited to

• homopyrimidine sequences since the presence of one or more purine residues destabilizes these complexes and favour the formation of less stable duplexes [8]. Therefore it would be of great value to adopt strategies for the stabilization of triplex structures even in the presence of non-pyrimidine bases. From the

• the major groove. In this work we applied this strategy to the synthesis of new mono-, di- and tri-functionalised PNA containing a 1-pyreneacetic acid residue linked to this C5-aminomethyl group (Figure 1b). As a model sequence, we chose a 9-mer (Figure 1c) complementary to a purine-rich tract of DNA

Stereoselective synthesis of carbocyclic analogues of the nucleoside Q precursor (PreQ₀)

• Sabin Llona-Minguez and
• Simon P. Mackay

Beilstein J. Org. Chem. 2014, 10, 1333–1338, doi:10.3762/bjoc.10.135

• the subject of extensive study [1] and several syntheses of the PreQ0 base or ribonucleoside [9][10][11][12][13][14][15][16] and queuosine [17] have been reported in the literature. Despite this long-lasting interest, examples of purine-based nucleosides containing a sugar or carbosugar motif at the 4

• to prepare diverse chiral amine building blocks and react them with a common halo-purine intermediate to obtain the desired final products. The pyrrolo[2,3-d]pyrimidine core of PreQ0 was furnished following a method described by Klepper et al. [13] (Figure 3). The two step process started with the

Synthesis, characterization and DNA interaction studies of new triptycene derivatives

• Sourav Chakraborty,
• Snehasish Mondal,
• Rina Kumari,
• Sourav Bhowmick,
• Prolay Das and
• Neeladri Das

Beilstein J. Org. Chem. 2014, 10, 1290–1298, doi:10.3762/bjoc.10.130

• generated when a purine (A/G) or a pyrimidine (C/T) base is stripped off from the DNA strand and this is considered as the most common type of DNA damage lesions. We generated one abasic site in a 48-base pair long oligomer duplex by treating the DNA (Figure 3) with Uracil DNA Glycosylase (UDG) enzyme

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

Synthesis and evaluation of cell-permeable biotinylated PU-H71 derivatives as tumor Hsp90 probes

• Tony Taldone,
• Anna Rodina,
• Erica M. DaGama Gomes,
• Matthew Riolo,
• Hardik J. Patel,
• Raul Alonso-Sabadell,
• Danuta Zatorska,
• Maulik R. Patel,
• Sarah Kishinevsky and
• Gabriela Chiosis

Beilstein J. Org. Chem. 2013, 9, 544–556, doi:10.3762/bjoc.9.60

• interest is the purine scaffold, including its representative PU-H71 (1a). This agent, currently in clinical investigation for cancer, binds to the N-terminal nucleotide binding pocket of Hsp90 [12]. We have shown that PU-H71 selects for tumor Hsp90 species, and therefore labeled derivatives of PU-H71 may

• . Results and Discussion Design and synthesis of biotinylated purine scaffold Hsp90 probes Geldanamycin (GM) is a benzoquinone ansamycin first isolated from a fermentation broth of Streptomyces hygroscopicus [15] and was the first reported Hsp90 inhibitor [16]. It has played a paramount role as a probe

• furthermore can efficiently bind to and trap Hsp90 in client-bound complexes allowing for the identification of global tumor Hsp90 proteomes by mass spectrometry [13]. We therefore set out here to design a series of biotinylated analogues derived from the purine scaffold Hsp90 inhibitor PU-H71 (1a) with the

Dipyrazolo[1,5-a:4',3'-c]pyridines – a new heterocyclic system accessed via multicomponent reaction

• Wolfgang Holzer,
• Gytė Vilkauskaitė,
• Eglė Arbačiauskienė and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2012, 8, 2223–2229, doi:10.3762/bjoc.8.251

• ]pyrimidine) [4], and Zolazepam (a pyrazolo[3,4-e][1,4]diazepine derivative, used in veterinary medicine) [5]. Particularly pyrazolopyrimidines are a very frequently accessed class of compounds [6] with the particular importance of the pyrazolo[3,4-d]pyrimidine core, which can closely mimic the purine system

Mutational analysis of a phenazine biosynthetic gene cluster in Streptomyces anulatus 9663

• Orwah Saleh,
• Katrin Flinspach,
• Lucia Westrich,
• Andreas Kulik,
• Bertolt Gust,
• Hans-Peter Fiedler and
• Lutz Heide

Beilstein J. Org. Chem. 2012, 8, 501–513, doi:10.3762/bjoc.8.57

• subunits of cytochrome d ubiquinol oxidase, and ppzR1 and ppzR2 to ABC transporters. The next gene, orf12, shows very high similarities to the primary metabolic enzyme allantoicase (allantoate amidohydrolase, EC 3.5.3.4), an enzyme of purine catabolism. It is separated from ppzR2 by a gap of 1.3 kb and

Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents

• Paul Knochel,
• Matthias A. Schade,
• Sebastian Bernhardt,
• Georg Manolikakes,
• Albrecht Metzger,
• Fabian M. Piller,
• Christoph J. Rohbogner and
• Marc Mosrin

Beilstein J. Org. Chem. 2011, 7, 1261–1277, doi:10.3762/bjoc.7.147

• preparation of a CDK inhibitor, purvalanol A (84). Thus, an I/Mg-exchange on the purine 85 with iPrMgCl·LiCl (64), followed by the transmetalation to the corresponding copper derivative with CuCl·2LiCl, and the addition of the lithiated aniline derivative 86, furnishes the amidocuprate 87. In the presence of

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

• Carolin Fischer and
• Burkhard Koenig

Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10

• , meningitis, pancreatitis and others. The conditions reported by Bakkestuen and Gundersen [73] gave only a low yield (26%). DMF as solvent and the absence of molecular sieves improved the yield (Scheme 24). The reaction conditions were compatible for different purine bases (100, 103) and for a variety of

Synthesis of 5-(6-hydroxy-7H-purine-8-ylthio)- 2-(N-hydroxyformamido)pentanoic acid

• Yanmei Zhang,
• Greg Elliot,
• Adrian Saldanha,
• Igor Tsigelny,
• Dennis Carson and
• Wolf Wrasidlo

Beilstein J. Org. Chem. 2010, 6, 742–747, doi:10.3762/bjoc.6.93

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

• [1][2][3][4]. As a part of our ongoing project, it seemed important to synthesize compounds with phosphonate and phenyl groups at one end of the hydrocarbon chain and a nucleic base residue at the other end. Previously, it was shown that compounds with similar structures inhibit purine nucleoside

Synthesis of some novel hydrazono acyclic nucleoside analogues

• Mohammad N. Soltani Rad,
• Ali Khalafi-Nezhad and
• Somayeh Behrouz

Beilstein J. Org. Chem. 2010, 6, No. 49, doi:10.3762/bjoc.6.49

• Abstract The syntheses of novel hydrazono acyclic nucleosides similar to miconazole scaffolds are described. In this series of acyclic nucleosides, pyrimidine as well as purine and other azole derivatives replaced the imidazole function in miconazole and the ether group was replaced with a hydrazone moiety

• different strategies were considered for the synthesis of the title compounds taking into account the differences in chemical behavior of purine and pyrimidine nucleobases compared to azoles. Because of their better solubility, reactivity and ease of separation of products, the reactions of the azole

• catalytic amount of acetic acid in ethanol, followed by heating at reflux (Scheme 1). For the synthesis of the purine and pyrimidine analogues of target compounds 2h–2o, we envisaged that there might be substantial problems in the synthesis of the desired ketones using similar method as outlined in Scheme 1

Synthesis of phosphonate and phostone analogues of ribose-1-phosphates

• Pitak Nasomjai,
• David O'Hagan and
• Alexandra M. Z. Slawin

Beilstein J. Org. Chem. 2009, 5, No. 37, doi:10.3762/bjoc.5.37

• step in the biosynthesis involves the fluorinase, an enzyme that catalyses nucleophilic attack of fluoride ion on SAM (3) to generate 5′-FDA (4). The initial fluorinated product 5′-FDA (4) is then depurinated by a purine nucleotide phosphorylase (PNP) to give 5-fluoro-5-deoxyribose-1-phosphate (5

Synthesis of 2-substituted 9-oxa-guanines {5-aminooxazolo[5,4-d]pyrimidin- 7(6H)-ones} and 9-oxa-2-thio- xanthines {5-mercaptooxazolo[5,4-d]pyrimidin- 7(6H)-ones}

• Subrata Mandal,
• Wen Tai Li,
• Yan Bai,
• Jon D. Robertus and
• Sean M. Kerwin

Beilstein J. Org. Chem. 2008, 4, No. 26, doi:10.3762/bjoc.4.26

• can be considered as 9-oxa-purine analogs of naturally occurring nucleic acid bases. Interest in this ring system has increased due to recent reports of biologically active derivatives. In particular, 5-aminooxazolo[5,4-d]pyrimidine-7(6H)-ones (9-oxa-guanines) have been shown to inhibit ricin. The

• prepared were found to inhibit ricin with IC50 ca. 1–3 mM. Keywords: Annulation; Click Chemistry; Cyclization; Purine Analogs; Ricin; Introduction Oxazolo[5,4-d]pyrimidines have been reported to possess a variety of biological activities including kinase inhibition [1][2], adenosine receptor antagonism

Microwave- assisted ring closure reactions: Synthesis of 8-substituted xanthine derivatives and related pyrimido- and diazepinopurinediones

• Joachim C. Burbiel,
• Jörg Hockemeyer and
• Christa E. Müller

Beilstein J. Org. Chem. 2006, 2, No. 20, doi:10.1186/1860-5397-2-20

• medicinal chemistry. Substitution at the 8-position of the purine ring is generally accessible by ring closure of a carboxamido-substituted uracil precursor. Although several procedures to accomplish this synthetic step have been suggested, it still remains difficult in many cases. Results Ring closure

• procedure allowed the preparation of a previously unaccessible diazepino [1,2,3-cd]purine. Yields were generally improved by the new method. The addition of THF as a co-solvent proved to be crucial. Conclusion A new, fast, and efficient ring closure method for the imidazole ring of xanthine derivatives and

• related tricyclic compounds has been developed. Apart from improving the syntheses of known compounds, some of which are important pharmacological tools or in development as novel drugs, it allows the preparation of 2-substituted diazepino [1,2,3-cd]purines – a new class of tricyclic purine derivatives