▁of ▁c oca ine ▁is ▁un stable ▁in ▁several ▁ways ▁besides ▁having ▁a ▁high ▁degree ▁of ▁l ability ; ▁for ▁instance : ▁the ▁C 2 ▁car b om eth ox y ▁in ▁its ▁b ios yn thesis ▁end - product ▁maintain s ▁the ▁ax ial ▁position , ▁which ▁can ▁under go ▁ep imer ization ▁via ▁sap on ification ▁to ▁obtain ▁the ▁former ▁in ▁an ▁equ atorial ▁position . ▁ ▁The ▁creation ▁of ▁the ▁following ▁analog ues ▁of ▁c oca ine ▁have ▁tradition ally ▁required ▁a ▁step ▁which ▁has ▁util ized ▁ 2 - C MT ▁as ▁an ▁intermediate ▁mole cular ▁product . ▁ ▁Ben zo yl ▁branch ▁cle av age ▁substitution s ▁( ex cluding ▁the ▁exhaust ive ▁phen yl ▁group ) ▁ ▁N . B . ▁F ries ▁re arr ang ement ▁product ▁of ▁asp ir in ▁used ▁to ▁make ▁sal but am ol . ▁It ▁is ▁relevant ▁to ▁the ▁prec ursor ▁here ▁though ▁because ▁the ▁migr ated ▁ac et yl ▁group ▁can ▁be ▁the ▁subject ▁of ▁a ▁h alo form ▁reaction . ▁A ▁more ▁direct ▁route ▁to ▁van ill ic ▁acid ▁though ▁is ▁just ▁ox id ation ▁of ▁the ▁van ill in ▁to ▁a ▁functional ized ▁ben zo ic ▁acid . ▁ ▁Ar ene ▁ben z ene - ring ▁ 2 ′ , ▁ 3 ′ , ▁ 4 ′ ▁( 5 ′ ▁& ▁ 6 ′ ) ▁position ▁( ary l ) ▁substitution s ▁ ▁para - subst it uted ▁ben zo yl m eth yle c gon ines ▁