5-(thien-2-yl) uracil analogs: 5-(5-methylthien-2-yl)-2′-deoxyuridine, 5-(5-thien-2-yl)-2′-deoxyuridine, and 5-(5-bromothien-2-yl)-2′-deoxyuridine

Abstract

Crystal structures of 5-(5-methylthien-2-yl)-2′-deoxyuridine (I), 5-(5-thien-2-yl)-2′-deoxyuridine (II) and 5-(5-bromothien-2-yl)-2′-deoxyuridine (III) have been obtained from data collected on a four-circle Enraf-Nonius diffractometer (CAD-4 system). Space group, unit/cell parameters and finalR indices are:I, monoclinic,P2₁,a=9.105(2),b=20.819(2),c=7.932(2) Å, β=98.79(2)°,R=5.7%;II, monoclinic,P2₁,a=8.720(4),b=20.793(4),c=7.884(4) Å, β=95.06(2)°,R=5.8%;III, monoclinic,P2₁,a=9.260(2),b=41.655(7),c=7.926(2) Å, β=97.996(13)°,R=9.4%. Structural properties of the title compounds are compared with those of 5-(5-chlorothien-2-yl)-2′-deoxyuridine (IV) previously reported in order to explain their affinity for HSV-1 thymidine kinase and their eventual interaction with viral DNA polymerase. The main structural features observed are the coplanarity of the uracil and thienyl cycles stabilized by a S−O intramolecular interaction and the formation of dimeric intermolecular H bonds between two uracil moieties.