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Search for "purines" in Full Text gives 36 result(s) in Beilstein Journal of Organic Chemistry.
Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications
Beilstein J. Org. Chem. 2014, 10, 1919–1932, doi:10.3762/bjoc.10.200
- is a reaction byproduct. However, prior investigations by others [23][24] and by us [25][26][27] have demonstrated the formation of phosphonium ions by the reaction of BOP with the oxygen atoms in amide linkages of purines and related heterocycles. In fact, related to these observations we have
Structure/affinity studies in the bicyclo-DNA series: Synthesis and properties of oligonucleotides containing bcen-T and iso-tricyclo-T nucleosides
Beilstein J. Org. Chem. 2014, 10, 1840–1847, doi:10.3762/bjoc.10.194
- ) the destabilization is higher as compared to purines as nearest neighbors (ON2). Two consecutive residues lead to less destabilization which is in line with earlier observations on tc-DNA where it was found that the highest Tm/modification were observed in fully modified oligonucleotides [37
OligArch: A software tool to allow artificially expanded genetic information systems (AEGIS) to guide the autonomous self-assembly of long DNA constructs from multiple DNA single strands
Beilstein J. Org. Chem. 2014, 10, 1826–1833, doi:10.3762/bjoc.10.192
- with unified entropy and enthalpy values from SantaLucia, et al. [14]. AEGIS bases B and P, both purines able to make 3 hydrogen bonds, are treated as G within Tm calculations, while S and Z, both pyrimidines able to form 3 hydrogen bonds, are treated as C. The exact Tm formula is: where R is the
- right: The presence of strong (C:G) and weak (T:A) nucleobase pairs complicates the design of self-assembling fragments. G-quartets can arise from G-rich sequences, with major groove interactions involving hydrogen bonding to the “Hoogsteen edge” of purines. Wobble pairing can compete with Watson
- intermolecular hybridization, especially at low concentrations of oligonucleotide. Watson–Crick pairing rules follow two rules of complementarity: (a) size complementarity (large purines pair with small pyrimidines) and (b) hydrogen bonding complementarity (hydrogen bond acceptors, A, pair with hydrogen bond
The chemoenzymatic synthesis of clofarabine and related 2′-deoxyfluoroarabinosyl nucleosides: the electronic and stereochemical factors determining substrate recognition by E. coli nucleoside phosphorylases
Beilstein J. Org. Chem. 2014, 10, 1657–1669, doi:10.3762/bjoc.10.173
- ab initio calculations in terms of the electronic structure (natural purines vs analogues) and stereochemical features (2FAra-1P vs Ara-1P) of the studied compounds to determine the substrate recognition by E. coli nucleoside phosphorylases. The second approach starts with the cascade one-pot
- electronic structure (natural purines vs analogues) and stereochemical features (2FAra-1P vs Ara-1P) of the studied compounds to determine the substrate recognition by E. coli nucleoside phosphorylases. Moreover, the cascade one-pot synthesis of clofarabine and related arabino-, xylo- and ribo-nucleosides (6
An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles
Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265
Chemoenzymatic synthesis and biological evaluation of enantiomerically enriched 1-(β-hydroxypropyl)imidazolium- and triazolium-based ionic liquids
Beilstein J. Org. Chem. 2013, 9, 516–525, doi:10.3762/bjoc.9.56
- default become core structures of the newly designed therapeutically active compounds. Many biomolecules (e.g., vitamins, amino acids, purines, alkaloids) containing an imidazole ring [3][4][5] meet the relevant biological requirements, therefore, its presence in active substances is very desirable
Diarylethene-modified nucleotides for switching optical properties in DNA
Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103
- reactivity the 5-position of pyrimidines (U/T and C) and the 8-position of purines (A and G) are preferred as chromophore modification sites. The assumption, that these points of attachment allow the chromophores to point into the major groove is only partially true, if at all. In particular, large and
- aromatic chromophores tend to insert into the base stack due to their hydrophobicity by changing the attached nucleoside from the natural anti- to the syn-conformation. The modification of the 8-position of purines clearly forces the nucleoside into the syn-conformation, which interferes with Watson–Crick
Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents
Beilstein J. Org. Chem. 2011, 7, 1261–1277, doi:10.3762/bjoc.7.147
- pyrimidines and purines are very important for the design of antiviral agents. The amination of this class of heterocycles is of particular importance. Recently, we developed an oxidative amination procedure for lithium derivatives using chloranil as oxidation agent [43]. We applied this procedure in the
Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds
Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10
- the required stoichiometric amount of copper and the long reaction time of 3 days [42]. For detailed insight into the structural requirements of active antimycobacterial purines 90, an easy access to 9-N-arylpurines 93 was required. Complete regioselectivity, and in most cases high chemoselectivity
- , was achieved by reacting 9-N-purines 91 with an excess of arylboronic acid 92 in the presence of copper(II) acetate, molecular sieves and phenanthroline (Scheme 22). Bakkestuen and Gundersen showed that electron-donating and electron-withdrawing substituents on the arylboronic acid were tolerated
- functional groups in the arylboronic acid (101, 104). Thus, a single reaction step from commercial precursors allowed the synthesis of new enterovirus inhibitors with activity in the low µM range [75]. A very recent example of 7-N-arylation of purines is the synthesis of highly substituted xanthine
Synthesis of some novel hydrazono acyclic nucleoside analogues
Beilstein J. Org. Chem. 2010, 6, No. 49, doi:10.3762/bjoc.6.49
- ], hereby, we wish to report the synthesis of some novel hydrazono acyclic nucleosides having similar scaffolds to the miconazole framework. In these compounds, the nucleobases including pyrimidines, purines and other azole derivatives were substituted as heterocyclic cores and the ether bond in miconazole
- . This proved to be the case, and the corresponding ketones 1h–1o could not be obtained satisfactorily by this method. The main limitation of using the aforementioned pathway for purines and pyrimidines is their low solubility in acetonitrile, which results in low yields of the corresponding ketones 1h
Microwave- assisted ring closure reactions: Synthesis of 8-substituted xanthine derivatives and related pyrimido- and diazepinopurinediones
Beilstein J. Org. Chem. 2006, 2, No. 20, doi:10.1186/1860-5397-2-20
- reaction with hexamethyldisilazane was studied under microwave conditions. Reaction times were dramatically reduced by the application of microwaves in the syntheses of the 8-styrylxanthine derivative istradefylline, and in the preparation of 2-substituted pyrimido [1,2,3-cd]purines. Furthermore, the new
- 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
- Simo et al. [26] In fact, this is the first access to 2-substituted diazepino [1,2,3-cd]purines. 2-Unsubstituted derivatives have previously been described by reaction of 10-amino-2,3,4,5-tetrahydropyrimido [1,6-a][1,3]diazepine-7,9-dione with triethyl orthoformate, but the reported synthetic procedure
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