. . "rine atoms, and trifluoromethyl, C1 -C3 alkyl, for example methyl, and C1 -C3 alkoxy, for example methoxy or ethoxy, groups, or R is an alkoxycarbonyl or benzyloxycarbonyl group of formula COOR2 wherein R2 is a C1 -C6 alkyl group, for example a methyl, ethyl or i-propyl group, or a benzyl group, or R is a substituted aminocarbonyl group of formula CONHR3 wherein R3 is a C1 -C6 alkyl group, for exa" . . .