H2 where R1 is selected from the group consisting of a phenylene group, a naphthylene group, or ##STR39## where X is as defined above; and said aromatic monoamine having the formula: R--NH2 ; where R is an aryl group bearing a substituent having the structure: ##STR40## and the solvent employed in step (a) is selected from the group consisting of N-methyl-2-pyrrolidone, cyclohexanone, diethyl ca