The present invention thus relates to novel compounds of the formula I or II ##STR4## in which n is zero or the number 1 or 2, R1 is a hydrogen atom, a C1 -C10 alkyl which is unsubstituted or substituted by halogen atoms, a C2 -C10 alkyl which is interrupted by ether oxygen atoms, or a phenyl or benzyl which is unsubstituted or substituted by halogen atoms, nitro groups, C1 -C4 alkyl or C1 -C4 alk