Preferably, {TAIL ~ the reactive group} is hydrogen are the reactive site is {HEAD ~ a hydroxy group} 
Preferably , { TAIL ~ the reactive group } is hydrogen are the reactive site is { HEAD ~ a hydroxy group }
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD