precipitated barium carbonate was filtered off the liltrate was neutralized with solid carbon dioxide and the precipitate was removed by filtration the liltrate was concentrated to a small volume to give 4 amino l methylpiperidine 4 carboxylic acid 32 0 g 95 yield m p 275 u00b0 280 u00b0 c dec ir kbr 3300 1655 1580 cm 1 m z 158 m 90 141 98 m oh 113 12 m co 2 h 96 100 71 52 1 h nmr 300 mhz c 5 d 5 n d 2 o u03b4 1 2 m 2h 1 48 s ch 3 n 1 7 m 2h 1 9 m 2h 2 0 m 2h lithium aluminum hydride powder 15 62 g 0 412 mole in dry tetrahydrofuran thf 600 ml was heated under reflux for 15 minutes after which 4 amino 1 methylpiperidine 4 carboxylic acid 31 0 g 0 196 mole in the form of a dry powder was added portionwise under nitrogen with efficient stirring after the addition was completed the reaction mixture was heated under reflux for four hours cooled to 0 u00b0 c under nitrogen with efficient stirring worked up by careful slow addition of water 20 ml 15 aqueous naoh 20 ml and again water 10 ml the reaction mixture was filtered and the precipitate was extracted with boiling thf 3 u00d7 150 ml the thf liltrate and the extracts were combined and the solvent removed at 25 mm to give a yellow viscous oil 28 0 g 98 9 yield ir neat 3320 nh 3200 br oh 1587 nh 2 1468 1448.