Abstract: The invention provides compounds of the formula 1 that are active against the HSV primase enzyme: wherein R1 is hydroxy or amino; R2 is hydrogen, halo, (C1-4)alkyl or (C1-4)alkoxy; R3 is hydrogen, halo, (C1-4)alkyl, (C1-4)alkoxy, amino or azido; R4 has the same significance as R2; R5 is hydrogen or (C1-4)alkyl; and R is (C1-7)alkyl, (C3-6)cycloalkyl, {phenyl(C1-7)alkyl}, {phenyl(C1-7)alkoxy}, {{(monocyclic heterocyclo)-{(C1-7)alkoxy}}, CH(W)C(O){O-(C1-4)alkyl} wherein W is hydrogen or (C1-7)alkyl, or  wherein Y is hydrogen or (C1-7)alkyl, and Z is (C1-7)alkyl, (C3-6) cycloalkyl, {(C3-6)cycloalkyl}- {(C1-7)alkyl}, phenyl(C1-7)alkyl or {{(monocyclic heterocyclo)-{(C1-7)alkyl}}, or Y and Z together with the nitrogen atom to which they are attached represent, 1-pyrrolidinyl, 1-piperidinyl, 4-morpholinyl or 1-(4-methylpiperazinyl); with the provisos that (1) when R is CH(W