ridino, pyrrolidino, acetylamino or benzoylamino group; (e) --OCH(CH2 N(CH3)2)2 (f) ##STR7## where R9 is a hydrogen atom, methyl or phenyl; (g) --OCH2 OCOR10 where R10 is C1-4 alkyl, methoxy or phenyl; (h) --OCH2 SCOR11 wherein R11 is C1-4 alkyl; (i) pyridinyloxy or pyridinylthio; (j) 1-(acetyloxy)ethoxy, (acetyloxy)phenylmethoxy, tetrahydro-5-oxo-2-furanyloxy, tetrahydro-2-oxo-3-furanyloxy, triph