R11 and R12 are each, independently, hydrogen, alkyl of 1 6 carbon atoms, aralkyl of 7 10 carbon atoms, {HEAD ~ cycloalkyl} of 3 8 carbon atoms, halogen, or {TAIL ~ trifluoromethyl} 
R11 and R12 are each , independently , hydrogen , alkyl of 1 6 carbon atoms , aralkyl of 7 10 carbon atoms , { HEAD ~ cycloalkyl } of 3 8 carbon atoms , halogen , or { TAIL ~ trifluoromethyl }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL