1-Piperidinepropanoic acid, 8-methyl-8-azabicyclo(3.2.1)oct-3-yl ester, dihydrochloride, exo- 87168-47-6 exo-8-Methyl-8-azabicyclo(3.2.1)oct-3-yl-1-piperidinepropanoate dihydrochloride