The invention relates to the novel products of formula (I):in which R1 represents optionally substituted -L-aryl or -L- heteroaryl, such that L represents: alkyl or CO or L'-X, where L' represents alkyl and X represents O or S; R2 represents H or alkyl; R3 represents alkyl optionally substituted with Hal; R4 represents H or Hal; these products being in all the isomer forms and the salts, as medicaments.本發明係關於一種作為藥劑之新穎式(I)產物,其中R1表示視情況經取代之-L-芳基或-L-雜芳基,其中L表示烷基或CO或L'-X,其中L'表示烷基且X表示O或S;R2表示H或烷基;R3表示視情況經鹵素取代之烷基;R4表示H或鹵素;此等產物可呈所有異構體形式及鹽。