135689-93-9Relevant articles and documents
Anchored Pd(0) Nanoparticles on Synthetic Talc for the Synthesis of Biaryls and a Precursor of Angiotensin II Inhibitors
Dos Santos, Beatriz F.,Da Silva, Beatriz A. L.,De Oliveira, Aline R.,Sarragiotto, Maria H.,Domingues, Nelson Luís C.
, p. 933 - 942 (2021)
The palladium-catalyzed Suzuki-Miyaura cross-coupling reaction is one of the most important and efficient reactions to prepare a variety of organic compounds, including biaryls. Despite the overwhelming number of reports related to this topic, some methodological difficulties persist in terms of catalyst handling, recovery, and reuse, as well as the reaction media. This work reports the rational design of new, efficient, cost-effective, and reusable palladium catalysts supported on synthetic talc for the Suzuki-Miyaura reaction. From the results, key points were identified: both designed catalysts accelerated the reaction in EtOH and an open-flask setup, affording moderate to excellent yields within a short time (e.g., 30 min) even for deactivated aryl halides; the protocol can be applied to a great number of both cross-coupling partners, showing an excellent functional group tolerance; the catalysts can be recovered and reused without significant loss of activity. This protocol was used for the synthesis of a precursor of angiotensin II inhibitors such as valsartan, losartan, irbesartan, and telmisartan.
Design of a Numbering-up System of Monolithic Microreactors and Its Application to Synthesis of a Key Intermediate of Valsartan
Nagaki, Aiichiro,Hirose, Katsuyuki,Tonomura, Osamu,Taniguchi, Satoshi,Taga, Toshiki,Hasebe, Shinji,Ishizuka, Norio,Yoshida, Jun-Ichi
, p. 687 - 691 (2016)
Synthesis of a key intermediate of valsartan was accomplished using five parallel monolithic microreactors connected to a split-and-recombine-type flow distributor. The channel resistances of the flow distributor were designed so as to minimize the flow maldistribution among reactors by using pressure drop compartment model, which is analogous to electrical resistance network.
Palladium-Catalyzed Late-Stage Direct Arene Cyanation
Zhao, Da,Xu, Peng,Ritter, Tobias
supporting information, p. 97 - 107 (2019/01/21)
Methods for direct benzonitrile synthesis are sparse, despite the versatility of cyano groups in organic synthesis and the importance of benzonitriles for the dye, agrochemical, and pharmaceutical industries. We report the first general late-stage aryl C–H cyanation with broad substrate scope and functional-group tolerance. The reaction is enabled by a dual-ligand combination of quinoxaline and an amino acid-derived ligand. The method is applicable to direct cyanation of several marketed small-molecule drugs, common pharmacophores, and organic dyes. Benzonitriles are some of the most versatile building blocks for organic synthesis, in particular in the pharmaceutical industry, but general methods to make them by direct C–H functionalization are unknown. In this issue of Chem, Ritter and coworkers describe a late-stage aryl C–H cyanation with broad substrate scope and functional-group tolerance, enabled by a palladium-dual-ligand catalyst system. The reaction may serve for the late-stage modification of drug candidates. Aryl nitriles constitute an important class of organic compounds that are widely found in natural products, pharmaceuticals, agricultural chemicals, dyes, and materials. Moreover, nitriles are versatile building blocks to access numerous other important molecular structure groups. However, no general method for direct aromatic C–H cyanation is known. All approaches to date require either an appropriate directing group or reactive electron-rich substrates, such as indoles, which limit their synthetic applications. Here we describe an undirected, palladium-catalyzed late-stage aryl C–H cyanation reaction for the synthesis of complex aryl nitriles that would otherwise be more challenging to produce. The wide substrate scope and good functional-group tolerance of this reaction provide direct and quick access to structural diversity for pharmaceutical and agrochemical development.
