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