{HEAD ~ An oxidizing agent}, preferably sodium dichromate, is added to {TAIL ~ the solution} to couple the diamine and aniline derivative 
{ HEAD ~ An oxidizing agent } , preferably sodium dichromate , is added to { TAIL ~ the solution } to couple the diamine and aniline derivative
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH