7-deazapurine and purine

The recognition of Watson-Crick base pairs carrying nucleobase protecting groups is reported as a new approach for DNA functionalization. The 2-amino groups of purine- and 7-deazapurine-2,6-diamine 2'-deoxyribonucleosides served as molecular targets for this functionalization. The 2-amino group withstands oligonucleotide deprotection with ammonia, whereas all other protecting groups are released after chemical DNA synthesis. On this basis, a method was developed for the selective functionalization of oligonucleotides at the 2-position of purines and 7-deazapurines. Melting experiments and

Topics: Base Pairing; DNA; Nucleic Acid Conformation; Oligonucleotides; Purines; Pyrenes

Purine DNA represents an alternative pairing system formed by two purines in the base pair with the recognition elements of Watson-Crick DNA. Base functionalization of 7-deaza-2'-deoxyxanthosine with ethynyl and octadiynyl residues led to clickable side chain derivatives with short and long linker arms. As complementary bases, purine-2,6-diamine or 7-deazapurine-2,6-diamine 2'-deoxyribonucleosides were used. 7-Deaza-7-iodo-2'-deoxyxanthosine served as a starting material for Sonogashira cross-coupling and the

Topics: Base Pairing; Diamines; Genetic Code; Ions; Purines; Xanthine

The butylidene-linker models 1-[2-(2,6-dimethylsulfanyl-9H-purin-9-yl)-2-methylidenepropyl]-4,6-bis(methylsulfanyl)-1H-pyrazolo[3,4-d]pyrimidine, C18H20N8S4, (XI), 7,7'-(2-methylidenepropane-1,3-diyl)bis[3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one], C20H22N6O2S2, (XIV), and 7-[2-(4,6-dimethylsulfanyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)-2-methylidenepropyl]-3-methyl-2-methylsulfanyl-3H-pyrrolo[2,3-d]pyrimidin-4(7H)-one, C19H21N7OS3, (XV), show folded conformations in solution, as shown by (1)H NMR analysis. This folding carries over to the crystalline state. Intramolecular π-π interactions are observed in all three compounds, but only (XIV) shows additional intramolecular C-H···π interactions in the solid state. As far as can be established, this is the first report incorporating the pyrrolo[2,3-d]pyrimidine nucleus for such a study. In addition to the π-π interactions, the crystal structures are also stabilized by other weak intermolecular C-H···S/N/O and/or S···N/S interactions.

Topics: Crystallography, X-Ray; Hydrogen Bonding; Magnetic Resonance Spectroscopy; Molecular Conformation; Purines; Pyrazoles; Pyrimidines; Pyrroles

A general method for Cu-catalyzed C-H sulfenylation of purines, 7-deaza- and 9-deazapurines with aryl- or alkyldisulfides has been developed. In purines, the reaction occurs at position 8, in 7-deazapurines at position 7 and in 9-deazapurines at position 9, leading to new interesting arylsulfanyl derivatives of purine or deazapurine bases. The resulting 8-arylsulfanylpurines undergo Liebesking-Srogl coupling with arylstannanes or boronic acids, whereas the (arylsulfanyl)deazapurines are not reactive under these conditions.

Topics: Copper; Crystallography, X-Ray; Purines; Sulfur