THE INVENTION RELATES TO THE NOVEL MATERIALS OF FORMULA (I), WHERE: R1 IS AN OPTIONALLY SUBSTITUTED L-ARYL OR -L-HETEROARYL, SUCH THAT L IS A SINGLE BOND, ALKYL, CO, OR CO-ALK, OR L’-X, WITH L’ BEING AN ALKYL AND X BEING O OR S; R2 IS H OR ALKYL; R3 IS AN ALKYL OPTIONALLY SUBSTITUTED BY HAL; AND R4 IS HOU HAL, WHEREIN SAID MATERIALS ARE IN ANY ISOMERIC FORM AND THE SALTS THEREOF, TO BE USED AS DRUGS.