. "Examples of other substituents are sulphonate, carboxylate, ureido C1-4 -alkyl, C1-4 -alkoxy, mono- and di-alkylamino, unsubstituted and mono- and di-alkylamino-sulphonyl and carbonyl, phenylamino, C1-4 -alkyl-carbonylamino, hydroxy, nitro and halogen, especially chlorine." . . . .