Synthesis and antiviral activity of 5-heteroaryl-substituted 2'-deoxyuridines

The synthesis of 5-heteroaryl-substituted 2'-deoxyuridines is described. The heteroaromatics were obtained from three different 5-substituted 2'-deoxyuridines. Cycloaddition reaction of nitrile oxides on the 5-ethynyl derivative 1 gave the isoxazoles 4a-e. The thiazole derivatives 14a-c were obtained from the 5-thiocarboxamide 11, while 5-pyrrol-1-yl-2'-deoxyuridine (17) could be synthesized directly from 5-amino-2'-deoxyuridine. The compounds were evaluated for antiviral activity. Selective activity against herpes simplex virus type 1 (HSV-1) and varicella zoster virus (VZV) was noted for 5-(3-bromoisoxazol-5-yl)-2'-deoxyuridine (4c). The compound was inactive against herpes simplex virus type 2, cytomegalovirus, and thymidine kinase (TK)-deficient mutants of HSV-1 and VZV, which indicates that, most likely, its antiviral activity depends on phosphorylation by the virus-specified TK.