Short and efficient synthesis of Guillou's Galanthamine intermediate

Recent advances in the total synthesis of galantamine, a natural medicine for Alzheimer's disease

Covering: 2006 to 2023(-)-Galantamine is a natural product with distinctive structural features and potent inhibitory activity against acetylcholine esterase (AChE). It is clinically approved for the treatment of Alzheimer's disease. The clinical significance and scarcity of this natural product have prompted extensive and ongoing efforts towards the chemical synthesis of this challenging tetracyclic structure. The objective of this review is to summarize and discuss recent progress in the total synthesis of galantamine from 2006 to 2023. The contents are organized according to the synthetic strategies for the construction of the quaternary center. Key features of each synthesis have been highlighted, followed by a summary and outlook at the end.

Recent Advances in the Hofmann Rearrangement and Its Application to Natural Product Synthesis

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C-N bond formation reactions are the most important transformations in (bio)organic chemistry because of the widespread occurrence of amines in pharmaceuticals, natural products, and biologically active compounds. The Hofmann rearrangement is a well-known method used for the preparation of primary amines from amides. But, the traditional version of the Hofmann rearrangement often gave relatively poor yields due to over-oxidation or due to the poor solubility of some amides in aqueous base, and created an enormous amount of waste products. Developments over the last two decades, in particular, have focused on refining both of these factors affecting the reaction. This review covers both the description of recent advances (2000-2019) in the Hofmann rearrangements and its applications in the synthesis of heterocycles, natural products and complex molecules of biological interest. It is revealed that organo-catalytic systems especially hypervalent iodine-based catalysts have been developed for the green and environmentally friendly conversion of carboxamides to primary amines and carbamates.

A Review on Recent Syntheses of Amaryllidaceae Alkaloids and Isocarbostyrils (Time period mid-2016 to 2017)

Alkaloids from the Amaryllidaceae have become valuable targets for synthetic organic chemists, mainly due to their wide variety of bioactivities and potential for utilization in medicinal chemistry ventures. In addition, the structural complexity of a number of these alkaloids has also been a reason for the interest in these compounds. In this review, the last 18 months of literature was perused and synthetic highlights have been presented here, with the hope to further focus attention on this interesting class of compounds and to encourage others to synthesize these compounds and their derivatives and/or analogues. The review contains examples of syntheses from most of the important alkaloid scaffold classes previously isolated from the Amaryllidaceae, namely: lycorine, crinine, galanthamine, tazettine, montanine, phenanthridone, phenanthridine, plicamine, mesembrine and some minor scaffolds (like gracilamine).