X in formula represents a hydrogen atom, a halogen atom, {HEAD ~ a hydrocarbon group} having {TAIL ~ 1 to 20 carbon atoms}, an alkoxy group or an amido group 
having
X in formula represents a hydrogen atom , a halogen atom , { HEAD ~ a hydrocarbon group } having { TAIL ~ 1 to 20 carbon atoms } , an alkoxy group or an amido group
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH