4-(Diethylphosphonomethyl)-2-pyridinecarboxamide → trans 4-(Diethylphosphonomethyl)-2-piperidinecarboxamide

Participants

Reaction Steps

A mixture of 1.19 g of 4-(diethylphosphonomethyl)-2-pyridinecarboxamide and 0.75 g of platinum oxide in 30 ml of acetic acid is hydrogenated at 3 atmospheric pressure for 6 hours at room temperature. The reaction mixture is filtered and the solvent is removed in vacuo. The residue is dissolved in methylene chloride and washed with a small volume of saturated sodium bicarbonate solution. After drying over magnesium sulfate, a methylene chloride solution of a 2:1 mixture of cis and trans 4-(diethylphosphonomethyl)-2-piperidinecarboxamide is obtained. After 3 days at room temperature this mixture isomerizes to the more stable cis isomer. Removal of the solvent in vacuo affords cis-4-(diethylphosphonomethyl)-2-piperidinecarboxamide as an oil, which is converted to the hydrochloride salt, melting at 155°-158°.

Provenance & Evidence