Author: Subject: Preparation of piperidine from pyridine?

Back in the early 1980s I developed a process to make Larvin insecticide at Union Carbide. The original process of using pyridine base and methylene chloride solvent for reaction, toluene for precipitation and methanol for isolation was replaced with pyridine (base as well as solvent) for reaction. The process was unconventional, it gave much higher yield, product stability (pyridine removed the trace transition metals in the raw materials) and easy of operation. I spent many months at the Woodbine, Georgia plant scaling this up and was exposed to pyridine many times. The myth was busted when my fourth child was born in 1983.

Synthesis of Piperidine from Pyridine – Thomas' …
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A new series of penta-substituted pyridine derivatives bearing the quinoline nucleus have been synthesized by base-catalyzed cyclocondensation reaction through multi-component reaction (MCR) approach. All the synthesized compounds were subjected to in vitro antimicrobial screening against three Gram positive bacteria (Bacillus subtilis, Clostridium tetani, Streptococcus pneumoniae), three Gram negative bacteria (Escherichia coli, Salmonella typhi, Vibrio cholerae), and two fungi (A. fumigatus, Candida albicans). Reviewing the data, majority of the compounds were found to be active against B. subtilis and C. tetani while the most effective compounds 4c and 4e demonstrated MIC 62.5 μg/ml against V. cholerae and E. coli respectively.

Synthesis of Piperidine Derivatives by Reduction of Pyridinium Salts

Structure-activity relationships of some pyridine, piperidine, ..
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One step in the (never completed) total synthesis I worked on in my Ph D was a Tebbe methylenation that called for dry pyridine. The stuff from our purification system was not good enough, so I distilled it myself on regular occasion. One late evening, I made a bonehead mistake and ended up exposing myself to quite a bit of hot pyridine by inhalation. I can verify firsthand the following effects described in Patty’s Industrial Hygiene and Toxicology: