A is {HEAD ~ halogen}, {TAIL ~ phenyl}, Sm phenyl, or NR5R6 
A is { HEAD ~ halogen } , { TAIL ~ phenyl } , Sm phenyl , or NR5R6
OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH