R9 is hydrogen, {HEAD ~ alkyl} of {TAIL ~ 1 6 carbon atoms}, or aralkyl of 7 10 carbon atoms 
of
R9 is hydrogen , { HEAD ~ alkyl } of { TAIL ~ 1 6 carbon atoms } , or aralkyl of 7 10 carbon atoms
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH