By selective chemical reactions we mean {HEAD ~ reactions} of {TAIL ~ a compound} or polymer containing two different functional groups with a reagent which reacts only or predominantly with one of the said functional groups, leaving the other functional group free to take part in a subsequent chemical reaction 
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By selective chemical reactions we mean { HEAD ~ reactions } of { TAIL ~ a compound } or polymer containing two different functional groups with a reagent which reacts only or predominantly with one of the said functional groups , leaving the other functional group free to take part in a subsequent chemical reaction
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH