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