The invention is concerned with novel pyrrole derivatives, a prcess for their manufacture, pharmaceutical compositions and the use of such compounds in medecine. In particular, the compounds of formula (I) are inhibitors of the human immunodeficiency virus reverse transcriptase enzyme which is involved in viral replication. Consequently the compounds of this invention may be advantageously used as therapeutic agents for HIV mediated process. The invention describes novel compounds of formula (I) wherein R1 is alkyl, cycloalkyl, aryl or heterocyclyl; R2 is alkyl, cycloalkyl, aryl or heterocyclyl; R3 is hydrogen, alkyl, cycloalkyl, aryl or heterocyclyl; R4 is hydrogen, alkyl, carboxyl, C(=O)R, CONR'R'', cyano or alkenyl, wherein R is hydrogen, alkyl, alkoxy, trifluoromethyl, methyl-oxy-carbonyl or ethyl-oxy-carbonyl, and wherein R' and R'', are independantly of each other, hydrogen, alkyl or aryl; R5 is alkyl, aryl or a group -Z-C(=O)R''', wherein Z is a single bond or -CH=CH-, and wherein R''' is hydrogen or alkyl; X represents S, S(O), S(O)¿2?, O, N(alkyl) or X-R?2¿ together CH¿2?-aryl or CH2-heterocyclyl; and with the proviso that only one of R?3 and R4¿ is hydrogen and alkyl in R3 is not CF¿3?; and hydrolyzable esters or ethers thereof or a pharmaceutically acceptable salt thereof.