Iodine Promoted One-Pot Synthesis of 2-Aryl Benzoxazoles from Amidoximes via Oxidative Cyclization and Ring Contraction

Chemistry, Biological Properties, and Bio-analysis of Tafamidis, a New Transthyretin Stabilizer: A Systematic Review

BACKGROUND

Cardiomyopathy is a global health crisis that affects people all over the world. Consequently, scientists felt compelled to look for and develop ever-more-powerful pharmaceuticals. For ATTR-CM, the only drug currently recommended by the European Society of Cardiology is Tafamidis.

OBJECTIVES

The primary aim of this review article is to understand the chemistry, pharmacodynamic, pharmacokinetic, and bio-analytical methods available for Tafamidis.

METHODS

A systematic review of the existing resources was accomplished up to 2022, comprising existing studies forming the database covering the existing resources from Web of Science, ScienceDirect, and PubMed.

RESULTS

The review was based on a systematic review of all the existing studies used to formulate the database. The study also illustrated the PRISMA design that systematically analyses the prevalent resources.

CONCLUSION

Minimal analytical techniques are observed for quantifying the Tafamidis and transthyretin kinetic stabiliser. Therapeutic, pharmacological, and analytical considerations for the novel drug Tafamidis are discussed in this review. Particular attention is paid to the many different analytical and bioanalytical methods currently available for estimating Tafamidis, and the need is highlighted to develop a straightforward, validated technique that meets green chemistry standards.

A Comprehensive Review on Chemistry and Biology of Tafamidis in Transthyretin Amyloidosis

Transthyretin amyloid cardiomyopathy and Transthyretin amyloid peripheral neuropathy are progressive disease conditions caused by Transthyretin amyloidosis (ATTR) fibril infiltration in the tissue. Transthyretin (TTR) protein misfolding and amyloid fibril deposits are pathological biomarkers of ATTR-related disorders. There are various treatment strategies targeting different stages in pathophysiology. One such strategy is TTR tetramer stabilization. Recently, a new TTR tetramer stabilizer, tafamidis, has been introduced that reduces the protein misfolding and amyloidosis and, consequently, disease progression in ATTR cardiomyopathy and peripheral neuropathy. This review will provide a comprehensive overview of the literature on tafamidis discovery, development, synthetic methods, pharmacokinetics, analytical methods and clinical trials. Overall, 7 synthetic methods, 5 analytical methods and 23 clinical trials have been summarized from the literature.

Facile Synthesis of Benzimidazoles via N-Arylamidoxime Cyclization

A facile synthesis of benzimidazoles was described by a one-pot process containing acylation-cyclization of N-arylamidoxime. This method provided an alternative synthesis of benzimidazoles with a certain diversity of substituted groups in acceptable yields (up to 96%). More importantly, the construction of bis-benzimidazole (8), the key intermediate for making telmisartan, was achieved by adopting this method that enabled avoiding the undesired nitration with nitric/sulfuric acid and the cyclization in polyphosphoric acid in the existing operations.

Oxime radicals: generation, properties and application in organic synthesis

N-Oxyl radicals (compounds with an N-O• fragment) represent one of the richest families of stable and persistent organic radicals with applications ranging from catalysis of selective oxidation processes and mechanistic studies to production of polymers, energy storage, magnetic materials design and spectroscopic studies of biological objects. Compared to other N-oxyl radicals, oxime radicals (or iminoxyl radicals) have been underestimated for a long time as useful intermediates for organic synthesis, despite the fact that their precursors, oximes, are extremely widespread and easily available organic compounds. Furthermore, oxime radicals are structurally exceptional. In these radicals, the N-O• fragment is connected to an organic moiety by a double bond, whereas all other classes of N-oxyl radicals contain an R2N-O• fragment with two single C-N bonds. Although oxime radicals have been known since 1964, their broad synthetic potential was not recognized until the last decade, when numerous selective reactions of oxidative cyclization, functionalization, and coupling mediated by iminoxyl radicals were discovered. This review is focused on the synthetic methods based on iminoxyl radicals developed in the last ten years and also contains some selected data on previous works regarding generation, structure, stability, and spectral properties of these N-oxyl radicals. The reactions of oxime radicals are classified into intermolecular (oxidation by oxime radicals, oxidative C-O coupling) and intramolecular. The majority of works are devoted to intramolecular reactions of oxime radicals. These reactions are classified into cyclizations involving C-H bond cleavage and cyclizations involving a double C=C bond cleavage.