{HEAD ~ A compound} 3 wherein {TAIL ~ R2} is hydrogen, R4 and R5 are hydrogen or methyl, and X is hydrogen, fluoro or chloro 
wherein
{ HEAD ~ A compound } 3 wherein { TAIL ~ R2 } is hydrogen , R4 and R5 are hydrogen or methyl , and X is hydrogen , fluoro or chloro
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH