An improved method for the synthesis of 3-quinuclidinone hydrochloride 4 from
piperidine-4-carboxylic acid 1 has been described. Reaction of piperidine-4-carboxylic acid 1 with
thionyl chloride and ethanol gave ethyl piperidine 4-carboxylate 2. It was further condensed with
methyl chloroacetate in presence of sodium carbonate to give ethyl 1-(2-methoxy-2-
oxoethyl)piperidine-4-carboxylate 3. One pot Dieckmann reaction of 3 in presence of potassium tertbutoxide
followed by hydrolysis and decarboxylation gave title compound azabicyclo[2.2.2]oct-3-one
Keywords: 3-quinuclidinone hydrochloride, Dieckmann reaction, isonepecotic acid, Gram scale synthesis.
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