A compound of formula I ##STR5## wherein: R represents {HEAD ~ phenyl} optionally substituted by {TAIL ~ a substituent} selected from the group consisting of hydroxy, chlorine, bromine, fluorine, methoxy, ethoxy, ethyl, methyl, isopropyl, isobutyl, isopropoxy, isobutoxy, amino, nitro, phenyl, mercapto, methylthio, methylsulfinyl and methylsulfonyl 
A compound of formula I # # STR5 # # wherein : R represents { HEAD ~ phenyl } optionally substituted by { TAIL ~ a substituent } selected from the group consisting of hydroxy , chlorine , bromine , fluorine , methoxy , ethoxy , ethyl , methyl , isopropyl , isobutyl , isopropoxy , isobutoxy , amino , nitro , phenyl , mercapto , methylthio , methylsulfinyl and methylsulfonyl
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH