Development of Two Complementary Syntheses for a Privileged CGRP Receptor Antagonist Substructure

Migraine drugs

According to recent studies, migraine affects more than 1 billion people worldwide, making it one of the world’s most prevalent diseases. Although this highly debilitating illness has been known since ancient times, the first therapeutic drugs to treat migraine, ergotamine (Gynergen) and dihydroergotamine (Dihydergot), did not appear on the market until 1921 and 1946, respectively. Both drugs originated from Sandoz, the world’s leading pharmaceutical company in ergot alkaloid research at the time. Historically, ergot alkaloids had been primarily used in obstetrics, but with methysergide (1-methyl-lysergic acid 1′-hydroxy-butyl-(2S)-amide), it became apparent that they also held some potential in migraine treatment. Methysergide was the first effective prophylactic drug developed specifically to prevent migraine attacks in 1959. On the basis of significantly improved knowledge of migraine pathophysiology and the discovery of serotonin and its receptors, Glaxo was able to launch sumatriptan in 1992. It was the first member from the class of triptans, which are selective 5-HT1B/1D receptor agonists. Recent innovations in acute and preventive migraine therapy include lasmiditan, a selective 5-HT1F receptor agonist from Eli Lilly, the gepants, which are calcitonin gene-related peptide (CGRP) receptor antagonists discovered at Merck & Co and BMS, and anti-CGRP/receptor monoclonal antibodies from Amgen, Pfizer, Eli Lilly, and others.

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Synthetic Approaches to the New Drugs Approved During 2020

New drugs introduced to the market are privileged structures that have affinities for biological targets implicated in human diseases and conditions. These new chemical entities (NCEs), particularly small molecules and antibody-drug conjugates (ADCs), provide insight into molecular recognition and simultaneously function as leads for the design of future medicines. This Review is part of a continuing series presenting the most likely process-scale synthetic approaches to 44 new chemical entities approved for the first time anywhere in the world during 2020.

New pharmaceuticals approved by FDA in 2020: Small-molecule drugs derived from amino acids and related compounds

Amino acids (AAs) play an important role in the modern health industry as key synthetic precursors for pharmaceuticals, biomaterials, biosensors, and drug delivery systems. Currently, over 30% of small-molecule drugs contain residues of tailor-made AAs or derived from them amino-alcohols and di-amines. In this review article, we profile 12 AA-derived new pharmaceuticals approved by the FDA in 2020. These newly introduced drugs include Tazverik (epithelioid sarcoma), Gemtesa (overactive bladder), Zeposia (multiple sclerosis), Byfavo (induction and maintenance of procedural sedation), Cu 64 dotatate, and Gallium 68 PSMA-11 (both PET imaging), Rimegepant (acute migraine), Zepzelca (lung cancer), Remdesivir (COVID-19), Amisulpride (nausea and vomiting), Setmelanotide (obesity), and Lonafarnib (progeria syndrome). For each compound, we describe the spectrum of biological activity, medicinal chemistry discovery, and synthetic preparation.

Streamlined Synthesis of Diaminopyridines by Pd-Catalyzed Ammonia Coupling with Deactivated Amino-Chloropyridines

An efficient and cost-effective two-step synthesis of diaminopyridines, fundamental building blocks of biologically active compounds, is reported. The advantages over previously reported routes include cost and wider availability of the bromo-chloropyridine starting materials and the straightforward accessibility to an extended array of diaminopyridine regioisomers. The key enabler of this synthetic strategy is the development of an unprecedented palladium-catalyzed coupling reaction of ammonia with chloropyridines deactivated by the presence of an alkylamino substituent. The coupling reaction was accomplished with very low catalyst loadings under remarkably mild reaction conditions, making the system particularly suitable for both academic and industrial applications. The utility of this methodology is exemplified by the application to the synthesis of highly relevant scaffolds, including the synthetic intermediates of the marketed drugs Ribociclib and Palbociclib.

Transition-metal-free C-H amidation and chlorination: synthesis of N/N'-mono-substituted imidazopyridin-2-ones from N-pyridyl-N-hydroxylamine intermediates

Non-symmetric 1,3-substituted imidazopyridin-2-ones are a common structural scaffold found among many biologically active molecules. Herein we report an efficient, mild, and transition-metal free C-H amidation strategy to access such a pyrido-fused cyclic urea framework in good yields and with a broad functional group tolerance.

Applications of Palladium-Catalyzed C-N Cross-Coupling Reactions

Pd-catalyzed cross-coupling reactions that form C–N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C–N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.

Fluorination methods in drug discovery

Fluorination reactions of medicinal and biologically-active compounds will be discussed. Late stage fluorination strategies of medicinal targets have recently attracted considerable attention on account of the influence that a fluorine atom can impart to targets of medicinal importance, such as modulation of lipophilicity, electronegativity, basicity and bioavailability, the latter as a consequence of membrane permeability. Therefore, the recourse to late-stage fluorine substitution on compounds with already known and relevant biological activity can provide the pharmaceutical industry with new leads with improved medicinal properties. The fluorination strategies will take into account different fluorinating reagents, either of nucleophilic or electrophilic, and of radical nature. Diverse families of organic compounds such as (hetero)aromatic rings, and aliphatic substrates (sp(3), sp(2), and sp carbon atoms) will be studied in late-stage fluorination reaction strategies.

Selective C-H fluorination of pyridines and diazines inspired by a classic amination reaction

Fluorinated heterocycles are prevalent in pharmaceuticals, agrochemicals, and materials. However, reactions that incorporate fluorine into heteroarenes are limited in scope and can be hazardous. We present a broadly applicable and safe method for the site-selective fluorination of a single carbon-hydrogen bond in pyridines and diazines using commercially available silver(II) fluoride. The reactions occur at ambient temperature within 1 hour with exclusive selectivity for fluorination adjacent to nitrogen. The mild conditions allow access to fluorinated derivatives of medicinally important compounds, as well as a range of 2-substituted pyridines prepared by subsequent nucleophilic displacement of fluoride. Mechanistic studies demonstrate that the pathway of a classic pyridine amination can be adapted for selective fluorination of a broad range of nitrogen heterocycles.

Practical way to imidazo[4,5-b] and [4,5-c]pyridine-2-ones via cascade ureidation/palladium-catalyzed cyclization

We developed an efficient one-pot tandem carbamoyl chloride amination and palladium-catalyzed intramolecular urea cyclization, which furnished high-throughput access to imidazo[4,5-b]pyridine-2-one and related imidazo[4,5-c]pyridine-2-one ring systems. Moderate to excellent yields were reported.