The drug 6, wherein {HEAD ~ R1} is {TAIL ~ a n pentyl group} or a 2methylhexyl group 
The drug 6 , wherein { HEAD ~ R1 } is { TAIL ~ a n pentyl group } or a 2methylhexyl group
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH