. "Examples of the substituents which the above-mentioned substituents may have include an alkyl group such as methyl group, ethyl group, and propyl group; an aralkyl group such as benzyl group and phenethyl group; an aryl group such as phenyl-group and biphenyl group; a heterocyclic group such as thienyl group, pyrrolyl group, and pyridyl group; amino groups such as dimethylamino group, diethylamino" . . . .