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