The compound 1 wherein R1 and R2 are phenyl and R3, {HEAD ~ R4} and {TAIL ~ R5} are each independently a lower alkyl 
The compound 1 wherein R1 and R2 are phenyl and R3 , { HEAD ~ R4 } and { TAIL ~ R5 } are each independently a lower alkyl
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH