Prospects for sexing mammalian sperm: Rupert P. Amann and George E. Seidel Jr. (Editors). Colorado Associated University Press, Boulder, CO, 1982. 288 pp. Cloth US$32.50, ISBN 0-87081-133-9; Paper US$22.50, ISBN 0-87081-134-7

Abstract

The title compound, the cyclic phosphate of the antiviral acyclonucleoside Ganciclovir (2′-NDG, DHPG), is itself a potent broad-spectrum antiviral agent, but with a different mechanism of action. The cyclic phosphate, 9-[[[(2-hydroxyl-1,3,2-dioxophosphorinan-5-yl)oxy] methyl]-P-oxide]guanine (2′-nor-cGMP, DHPG-cMP), crystallizes in the monoclinic space group P21/n with until cell dimensions a = 6.612(1) Å, b = 11.562(4) Å, c = 19.231(5) Å and β = 91.786(2)° at −165°C. The N7 of the guanine base is protonated, so that the molecule is in a zwitterionic form, with two water molecules in the asymmetric unit. The principal conformational features of DHPG-cMP in the crystal are as follows: the acyclic chain is partially folded; the six-membered cyclic phosphate ring is in a chair form with C3′, O3′, C5′ and O5′ in a plane; P and C4′ are displaced in diametrically opposite directions from this plane; the O4′ is in the axial orientation with respect to this ring; and the aglycon is in the high syn conformation about the glycosidic bond. The conformation of the cyclic phosphate ring in aqueous medium, determined by means of 1H-NMR spectroscopy, is similar to that in the crystalline form. The conformational features of DHPG-cMP were compared with those of the parent DHPG and other related compounds and, in particular, with those of the second messenger 3′:5′-cGMP, of which it is a close structural analogue. Previously reported substrate/inhibitor properties of these compounds in several enzyme systems are examined in relation to the possible mechanism of antiviral activity of DHPG-cMP as a second messenger analogue of cGMP.