Intermediate compounds of non-nucleoside reverse transcriptase inhibitors

Compounds of the formula I: ##STR1##

where;

R₁ is O, S;

R₂ is an optionally substituted nitrogen-containing heterocycle, wherein the nitrogen is located at the 2 position relative to the (thio)urea bond;

R₃ is H, C₁-C₃ alkyl,

R₄-R₇ are independently selected from H, C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, haloC₁-C₆ alkyl, C₁-C₆ alkanoyl, haloC₁-C₆ alkanoyl, C₁-C₆ alkoxy, haloC₁-C₆ alkoxy, C₁-C₆ alkyloxy-C₁-C₆ alkyl, haloC₁-C₆ alkyloxy-C₁-C₆ alkyl hydroxy-C₁-C₆ alkyl, amino-C₁-C₆ alkyl, carboxy-C₁-C₆ alkyl, cyano-C₁-C₆ alkyl, amino, carboxy, carbamoyl, cyano, halo, hydroxy, keto;

X is (CH₂)_n-D(CH₂)_m;

D is O, S;

n and m are independently 0 or 1;

and prodrugs and pharmaceutically acceptable salts thereof, have utility as inhibitors of HIV-1 reverse transcriptase, particularly drug escape mutants.