Piperidine Alkaloids General

Piperidine Alkaloids (General).—As part of a study of the role of cadaverine (1) in the biosynthesis of piperidine alkaloids samples of (1), stereospecifically labelled with tritium at C-1, were tested as precursors for N-methylpelletierine (2). These samples were prepared by decarboxylation of L-lysine through the action of L-lysine 

Staunton, in The Alkaloids , ed. J. E. Saxton (Specialist Periodical Reports), The Chemical Society, London, 1972, Vol. 2. 

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In addition to a number of piperidine alkaloids, at least 19 pyrrolidine alkaloids have been reported from secretions of thief ants and fire ants of the genera Solenopsis and Mono-morium. In general, these compounds occur in minute amounts (50 xg/ant) (Jones and Blum, 1983 Massiot and Delaude, 1986 Numata and Ibuka, 1987). 

Piperidine alkaloids arise from lysine in much the same way that pyrrolidine alkaloids arise from ornithine. A total of about 700 alkaloids of these two groups are known (Ver-poorte et al, 1991). The product of decarboxylation of lysine, cadaverine, generally seems to be incorporated as an unsymmetrical intermediate, but, in some instances, a symmetrical intermediate may be involved. This has been investigated by feeding [6--lysine and [2--lysine (Fig. 29.8). A pathway involving a bound form of cadaverine (25) to pyridoxal that accounts for most observed chemical data has been proposed (Spenser, 1970) (Fig. 29.8). Decarboxylation occurs with retention of configuration. 

The biosynthesis of lycopodium, quinohzine, pyridine, or a-pyridone-type alkaloids isolated from Lycopodium species, shares some common steps with the biosynthesis of the previously mentioned piperidine alkaloids [28, 35, 36], The first general intermediate for all lycopodium alkaloids is the piperidine alkaloid pelletierine (45). Again, besides the... 

In spite of the diverse nature of alkaloid structures, two structural units, i.e. fused pyrrolidine and piperidine rings in different oxidation states, appear as rather common denominators. We therefore chose to give several examples for four types of synthetic reactions which have frequently been used in alkaloid total synthesis and which provide generally useful routes to polycyclic compounds with five- or six-membered rings containing one nitrogen atom. These are ... 

Piperidine-type metacyclophane alkaloids have four chiral carbon atoms C-3, C-5, C-9, and C-ll. With 96 in hand, Fujita et al. hydrogenated its pyridine ring over Adams catalyst and Raney nickel in order to define the relative stereochemistry of C-5 and C-9. They obtained a single crystalline hexahydro derivative in quantitative yield. Catalytic hydrogenation of substituted pyridines generally results in cis products. Therefore, one can assume the cis relationship of C-5 and C-9 hydrogens in the foregoing... 

The piperidine ring system is found in numerous biologically active alkaloids and a number of reviews have been published on synthetic methods to form piperidines, generally from acyclic starting materials <2000S1781,... 

Introductory surveys of these groups form parts of two chapters in an excellent general volume on the chemistry of alkaloids.1,2 A short review dealing with selected alkaloids of potential medicinal interest includes mention of a pyridine alkaloid.3 A review on the use of n.m.r. spectroscopy in structural and conformational elucidation of piperidine, pyridine, and monoterpenoid alkaloids is not readily accessible.4... 

Comparison of the spectral data with those of pandicine (519), in fact revealed generally good agreement of the aromatic shifts in particular as well as those of the non-aromatic carbons, with the exception of the piperidine ring D carbons. The other unit of the bisindole was clearly shown to be a 10-alkyl-11-oxy-tabersonine-jS-epoxide from the excellent correlation of the non-aromatic shifts with those of pachysiphine (547), and the aromatic shifts with those of vandrikine and the bisindole alkaloid vincarubine (517). 

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