each R17 is independently hydrogen, {HEAD ~ saturated hydrocarbyl} or {TAIL ~ substituted saturated hydrocarbyl}; and 
each R17 is independently hydrogen , { HEAD ~ saturated hydrocarbyl } or { TAIL ~ substituted saturated hydrocarbyl } ; and
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH