This invention concerns the use of the compounds of formula ##STR1##

the N-oxides, the pharmaceutically acceptable addition salts, quaternary amines and the stereochemically isomeric forms thereof, wherein -a¹=a²-a³=a⁴- forms a phenyl, pyridinyl, pyrimidinyl, pyridazinyl or pyrazinyl with the attached vinyl group; n is 0 to 4; and where possible 5; R¹ is hydrogen, aryl, formyl, C_1-6alkylcarbonyl, C_1-6alkyl, C_1-6alkyloxycarbonyl or substituted C_1-6alkyl; each R² independently is hydroxy, halo, optionally substituted C_1-6alkyl, C_2-6alkenyl or C_2-6alkynyl, C_3-7cycloalkyl, C_1-6alkyloxy, C_1-6alkyloxycarbonyl, carboxyl, cyano, nitro, amino, mono- or di(C_1-6alkyl)amino, polyhalomethyl, polyhalomethyloxy, polyhalomethylthio, —S(O)_pR⁴, —NH—S(O)_pR⁴, —C(O)R⁴, —NHC(O)H, —C(O)NHNH₂, —NHC(O)R⁴, —C(NH)R⁴ or a 5-membered heterocyclic ring; p is 1 or 2; L is optionally substituted C_1-10alkyl, C_2-10alkenyl, C_2-10alkynyl or C_3-7cycloalkyl; or L is —X—R³ wherein R³ is optionally substituted phenyl, pyridinyl, pyrimidinyl, pyrazinyl or pyridazinyl; X is —NR¹—, —NH—NH—, —NN—, —O—, —C(=O)—, —CHOH—, —S—, —S(O)— or —S(O)₂—; aryl is optionally substituted phenyl; for the manufacture of a medicine for the treatment of subjects suffering from HIV (Human Immunodeficiency Virus) infection.