Any aniline derivative having {HEAD ~ an unsubstituted NH2 group} or akylamine having {TAIL ~ an unsubstituted NH2 group} is then added to the mixture 
Any aniline derivative having { HEAD ~ an unsubstituted NH2 group } or akylamine having { TAIL ~ an unsubstituted NH2 group } is then added to the mixture
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH