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