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