{HEAD ~ R14} is hydrogen, {TAIL ~ nitro}, cyano or C1 4 alkylcarbonyl; and 
is
{ HEAD ~ R14 } is hydrogen , { TAIL ~ nitro } , cyano or C1 4 alkylcarbonyl ; and
HEAD HEAD HEAD HEAD HEAD REL OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH