{HEAD ~ Compounds} of formula B1 with amide group X are {TAIL ~ diamides} obtained from macromolecular diamines by well known acylation reactions using e.g., the acid chlorides or anhydrides mentioned above 
are
{ HEAD ~ Compounds } of formula B1 with amide group X are { TAIL ~ diamides } obtained from macromolecular diamines by well known acylation reactions using e.g. , the acid chlorides or anhydrides mentioned above
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH