Research Progress in Chemical Synthesis and Biosynthesis of Bioactive Pyridine Alkaloids.

Pyridine alkaloids possess important biological activities and are widely used in fields such as medicine and pesticides. This paper comprehensively reviews the research progress in the chemical synthesis and biosynthesis of pyridine alkaloids. In terms of chemical synthesis, there are diverse synthesis methods for arylpyridine compounds. For example, 2,4,6-triarylpyridine can be synthesized by using iron-organic framework materials or other reagents. The 3-ethylsulfone pyridine compounds with aryltriazole structures can be synthesized through specific reactions. And 2- arylpyridine can also be synthesized in this way. Heterocyclic pyridine compounds can be prepared into their corresponding derivatives through multiple approaches. The synthesis of polysubstituted pyridine adopts reactions such as cycloaddition, Diels-Alder, condensation, cyclization, and aromatization. The synthesis of polypyridine focuses on the construction of new complexes. Other synthesis methods such as ultrasound-assisted synthesis are also introduced. The main biosynthesis pathways include the co-synthesis of polyketide synthase and non-ribosomal peptide synthase, the origin of lysine, the participation of aspartate, and the synthesis of thiopeptide antibiotics. Meanwhile, the biosynthesis pathways of pyridomycin, pyridine pigment compounds in functional red yeast rice, and vitamin B6 were also discussed, which provides a theoretical basis for further research and application of pyridine alkaloids.