R10 is independently selected from the group consisting of {TAIL ~ H}, {HEAD ~ alkyl}, and arylalkyl 
R10 is independently selected from the group consisting of { TAIL ~ H } , { HEAD ~ alkyl } , and arylalkyl
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH