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