Abstract Heating the ammonium salt of (4-carboxy-1-methyl-4-piperidinyl) acetic acid (XII) gave 8-methyl-2, 8-diazaspiro [4, 5] decane-1, 3-dione (II) which was N-alkylated with 2- bromoethanol and 4-bromobutanol to give the alcohols III and V. Compound III was transformed to the chloro compound VI which was reacted with the sodium salt of hexahydrobenzilic acid to give the ester VII. Compound V was transformed to the 4- ...
