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