Synthesis and stereochemistry of quinolizidine and the monomethylquinolizidines, and of their salts and quaternary salts was written by Moynehan, T. M.;Schofield, K.;Jones, Richard A. Y.;Katritzky, A. R.. And the article was included in Journal of the Chemical Society in 1962.Electric Literature of C7H6N2 This article mentions the following:
Infrared and proton resonance spectra of quinolizidine and both racemic forms of 1-, 2-, 3-, and 4-methylquinolizidine indicate that in all except one of these compounds the ring system exists predominantly in the trans fused conformation. The exception is that 4-methylquinolizidine in which the 10- and 4-hydrogen atom are trans with respect to each other; this compound appears to adopt preferentially the conformation in which the rings are cis fused and the methyl group is equatorial. The stereochemistry of the proton salts of these bases is very similar to that of the free bases. The two possible methiodides of quinolizidine have been obtained, one by quaternization of quinolizidine, the other by cyclization of 2-iodo-4-butyl-1-methylpiperidine. Proton resonance spectra of the methiodides indicate that the one formed by direct quaternization contains the trans fused ring structure, arid that formed by cyclization the cis fused ring structure. Generally, quaternization of methylquinolizidines which contain in the trans fused conformation an axial methyl group on the same side of the molecule as the nitrogen lone-pair leads to salts with the cis fused ring configuration. The problem of the size of the nitrogen lonepair is discussed. In the experiment, the researchers used many compounds, for example, 4-Methylpicolinonitrile (cas: 1620-76-4Electric Literature of C7H6N2).
4-Methylpicolinonitrile (cas: 1620-76-4) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. Reduced pyridines, namely tetrahydropyridines, dihydropyridines and piperidines, are found in numerous natural and synthetic compounds. The synthesis and reactivity of these compounds have often been driven by the fact many of these compounds have interesting and unique pharmacological properties. Electric Literature of C7H6N2