Abstract: The present invention relates to compounds of the following formula (I): or a pharmaceutically acceptable salt thereof, a stereoisomer or a mixture of stereoisomers in any proportion, in particular a mixture of enantiomers, and particularly a racemate mixture, in which R represents a (C1-C10)alkyl group substituted with one or more, preferably one or two, groups chosen from COOH and NHR1, with R1 representing a hydrogen atom or a -Alk, —C(O)-Alk or —C(O)O-Alk group, Alk representing a (C1-C6)alkyl group, as well as a method for preparing them, and their use as a medicine, notably for treating an infection with a retrovirus such as HIV.