The synthesis and properties of some 5-substituted uracil derivatives.

The problems encountered in the synthesis of 5-vinyl-2'-deoxyuridine are outlined and the synthesis of 5-bromoethynyl-2'-deoxyuridine described. E-5-(2-Bromovinyl)-2'-deoxyuridine is the most potent and specific agent against some herpes viruses yet discovered; we have now synthesised the Z-isomer and this appears to be essentially biologically inert.