or Q and R2 D together form the group ##STR19## wherein R18 is ##STR20## {HEAD ~ R16} and R17 are independently selected from {TAIL ~ the group} consisting of CH2 , CH , C , 
independently selected from
or Q and R2 D together form the group # # STR19 # # wherein R18 is # # STR20 # # { HEAD ~ R16 } and R17 are independently selected from { TAIL ~ the group } consisting of CH2 , CH , C ,
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 OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH