Pyridine and piperidine alkaloids

The compounds of pyridine and piperidine alkaloids are plant bases and are being isolated from insects and from amphibians and marine animals. They are widely distributed in nature and they perform a number of different functions in nature, such as train pheromones and defense mechanisms in insects. In many cases, the stereochemistry is complex and the syntheses require sophisticated asymmetric methods. This chapter discusses these compounds for their synthesis and derivatives, and their applications. The section on terpenoid piperidine alkaloids found in plants is used for the treatment of rheumatism and is discussed as an analgesic in the chapter. A number of polyhydroxypiperidines (azahexoses) are known for creating much interest, as they show glycosidase inhibitory activity. The benefits and applications of spiropiperidine alkaloids are explained for their chemical methods and resulting compounds. The perhydroquinoline alkaloids—such as lepadin A (103), a cis-decahydroquinoline alkaloid, can be obtained from the north-sea tunicate clavelinia lepadiformis. The different types of pyridine alkaloids are presented for the reader. The compounds pyridine, dihydropyridone and tetrahydropiperidone alkaloids are briefly discussed.