R2 is hydrogen, {TAIL ~ nitro}, {HEAD ~ amino} or mono or dialkylamino; and 
R2 is hydrogen , { TAIL ~ nitro } , { HEAD ~ amino } or mono or dialkylamino ; and
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH