{TAIL ~ The compound} 2 wherein R4 is {HEAD ~ an substituted or unsubstituted phenyl or thienyl group} 
{ TAIL ~ The compound } 2 wherein R4 is { HEAD ~ an substituted or unsubstituted phenyl or thienyl group }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD