prov:value
| - a lower alkyl group, preferably a methyl group, a lower alkoxy group, preferably a methoxy group, a hydroxy or carboxy group or a sulfonic acid group and R2 is a hydrogen atom, a halogen atom, preferably a chlorine or bromine atom, a lower alkyl group, preferably a methyl group, a lower alkoxy group, preferably a methoxy group, a nitro group or a sulfonic acid group, it being possible for R1 and R
|