prov:value
| - ro, 1 or 2 and, for example, R1 is an H atom, C1 -C10 -alkyl, phenyl or benzyl, R2, R3, R4, R5, R6, R7 and R8 independently of one another are each an H atom, halogen atom, C1 -C10 alkyl, phenyl, naphthyl or the radical --COOR9, ##STR2## or --SO2 R9, in which R9 is C1 -C6 alkyl or phenyl, X is O, S or NR10, in which R10 is an H atom, C1 -C6 alkyl or phenyl, Y is a radical of the following formulae
|