Crystal and molecular structure of 9‐vinyladenine

Abstract

The title compound 9-vinyladenine crystallizes in the monoclinic space group C2/c with 16molecules in the unit cell and the lattice parameters a = 13.682, b = 10.260, c = = 21.674 A, /? = 97.72". The crystal structure has been determined by direct methods and refined by full matrix least squares calculations up to the discrepancy factor R = 0.045.The two symmetry independent molecules differ in the orientation of the vinyl group relative to the adenine frame.Die Titelverbindung 9-Vinyladenin kristallisiert, in der monoklinen Raumgruppe C 2 / c mit 16 Molekulen in der Elementarzelle und den Gitterkonstanten a = 13,682, b = 10,250, e = 21,674 A, /I = 97,72". Die Kristallstruktur wurde mit direkten Methoden bestimmt und mit der Methode der kleinsten Quadrate bis zu einem R-Wert von 0,045 verfeinert.Die zwei symmetrieunabhangigen Molekule unterscheiden sich in der Orientierung der Vinylgruppe relativ zum Adeninkfirper.

Biomesogenic (pre)ordering phenomena and matrix reactions of nucleosides on polyuridylic acid templates studied by scanning force microscopy

“…Owing to the rapid development of genetechnological alternatives, the early and not so easy to solve questions remained an open problem. The impressive regularities manifested in the x-ray investigation of 1-vinylcytosine 38 and 9-vinyladenine 19 but might forward suggestions in the direction of ordered artificial arrays, which might be influenced by internal preordering of the systems themselves or, as might be the case here, by an additional biomesogen (pre)ordering of an assembling polynucleotide master strand. For our picture, all these models of preferentially triplestranded arrangements in the case of homopolymers and dsRNA-like hybrids in the case of alternating copolymers add evidence that the diameter of ¾3 nm taken from the images of the zooms might meet the expectations of the formerly illustrated and discussed triple-stranded arrays, in which the artificial backbone unites the two native polynucleotide strands.…”

“…Assembles of cysteine-functionalized adenine monomers (cysA), 15,16 as representative of similar 9-vinyladenine (vA) 16,19 and adenosine (Ado) 6,7 monomers for base-pairing in Watson-Crick and/or Hoogsteen-type arrangements.…”

“…16,21 For computer simulations (Figs 1, 2, 4, 6), the vA data were taken from x-ray investigations. 19 The Ado and RNA geometries were taken from the data bank and cysA 15,16 was modelled by refinement procedures. Figure 2 demonstrates with hypothetical Watson-Crick and Hoogsteen arrangements, the facilities of nucleoside (or analogue) monomers adjusted to an organizing polynucleotide U n matrix.…”