Alcoholic potash decomposes it into piperidine, C5H,1N, and piperic acid, C 12 H 10 O 4.
The synthesis of piperine follows from the interaction of piperyl chloride (formed from piperic acid and phosphorus pentachloride) and piperidine (L.
Braun (Ber., 1904, 37, p. 35 8 3) has prepared pentamethylene derivatives from piperidine by the action of phosphorus pentachloride.
On heating piperidine with phosphorus pentachloride to 200°C. in a sealed tube pentamethylene dichloride is obtained, and this on treatment with potassium phthalimide gives a condensation product of composition, C 6 H 4 [CO] 2 N(CH 2) 5 N[CO] 2 C 6 H 4, which is finally hydrolysed by hydrochloric acid.
6, p. 329); and by heating piperidine in acetic acid solution with silver acetate (J.
Piperidine or hexa-hydropyridine, C 5 H 11 N, was first obtained in 1848 by distilling piperine with lime.
The piperidine ring is easily split.
Braun (Ber., 1904, 37, p. 2915) showed that benzoyl piperidine, when heated with phosphorus pentachloride to 200° C. in sealed tubes, yields benzonitrile, and pentamethylene dichloride, thus leading to a simple method of preparing pentamethylene compounds.
The subject has been especially studied by Skraup, Konigs, and von Miller; Kiinigs and von Miller have proposed formulae consisting of a piperidine ring substituted with a vinyl group; in the former that is a bridge of CH 2 C(OH) from the nitrogen atom to the -y-carbon atom, connexion with the quinoline residue being made at the hydroxylic carbon atom through a CH2 group: whilst in the latter the piperidine ring is substituted by a methyl group in addition to the vinyl group and the bridge is simply C(OH), with which connexion is made as before.
CONINE, or Coniine (a-propyl piperidine), C 5 H 17 N, an alkaloid occurring, associated with y-coniceine, conhydrine, pseudoconhydrine and methyl conine, in hemlock (Conium maculatum).
This substance when heated with hydriodic acid to 300° C. is converted into a-propyl piperidine, which can also be obtained by the reduction of a-allyl pyridine (formed from a-methyl pyridine and paraldehyde).
The a-propyl piperidine so obtained is the inactive (racemic) form of conine, and it can be resolved into the dextroand laevo-varieties by means of dextro-tartaric acid, the d-conine d-tartrate with caustic soda giving d-conine closely resembling the naturally occurring alkaloid.
The transformation of piperidine into pyridine by W.