https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Multicomponent reactions (MCRs) are fundamentally different from two-component reactions in several aspects. Among the MCRs, those with isocyanides have developed into popular organic-chemical reactions in the pharmaceutical industry for the preparation of compound libraries of low-molecular druglike compounds. With a small set of starting materials, very large libraries can be built up within a short time, which can then be used for research on medicinal substances. Due to the intensive research of the last few years, many new backbone types have become accessible. MCRs are also increasingly being employed in the total synthesis of natural products. MCRs and especially MCRs with isocyanides offer many opportunities to attain new reactions and basic structures. However, this requires that the chemist learns the “language” of MCRs, something that this review wishes to stimulate.

Multicomponent Reactions with Isocyanides.

Once considered the 'holy grail' of organometallic chemistry, synthetically useful reactions employing C-H bond activation have increasingly been developed and applied to natural product and drug synthesis over the past decade. The ubiquity and relative low cost of hydrocarbons makes C-H bond functionalization an attractive alternative to classical C-C bond forming reactions such as cross-coupling, which require organohalides and organometallic reagents. In addition to providing an atom economical alternative to standard cross - coupling strategies, C-H bond functionalization also reduces the production of toxic by-products, thereby contributing to the growing field of reactions with decreased environmental impact. In the area of C-C bond forming reactions that proceed via a C-H activation mechanism, rhodium catalysts stand out for their functional group tolerance and wide range of synthetic utility. Over the course of the last decade, many Rh-catalyzed methods for heteroatom-directed C-H bond functionalization have been reported and will be the focus of this review. Material appearing in the literature prior to 2001 has been reviewed previously and will only be introduced as background when necessary. The synthesis of complex molecules from relatively simple precursors has long been a goal for many organic chemists. The ability to selectively functionalize a molecule with minimal pre-activation can streamline syntheses and expand the opportunities to explore the utility of complex molecules in areas ranging from the pharmaceutical industry to materials science. Indeed, the issue of selectivity is paramount in the development of all C-H bond functionalization methods. Several groups have developed elegant approaches towards achieving selectivity in molecules that possess many sterically and electronically similar C-H bonds. Many of these approaches are discussed in detail in the accompanying articles in this special issue of Chemical Reviews. One approach that has seen widespread success involves the use of a proximal heteroatom that serves as a directing group for the selective functionalization of a specific C-H bond. In a survey of examples of heteroatom-directed Rh catalysis, two mechanistically distinct reaction pathways are revealed. In one case, the heteroatom acts as a chelator to bind the Rh catalyst, facilitating reactivity at a proximal site. In this case, the formation of a five-membered metallacycle provides a favorable driving force in inducing reactivity at the desired location. In the other case, the heteroatom initially coordinates the Rh catalyst and then acts to stabilize the formation of a metal-carbon bond at a proximal site. A true test of the utility of a synthetic method is in its application to the synthesis of natural products or complex molecules. Several groups have demonstrated the applicability of C-H bond functionalization reactions towards complex molecule synthesis. Target-oriented synthesis provides a platform to test the effectiveness of a method in unique chemical and steric environments. In this respect, Rh-catalyzed methods for C-H bond functionalization stand out, with several syntheses being described in the literature that utilize C-H bond functionalization in a key step. These syntheses are highlighted following the discussion of the method they employ.

/pdf/rhodium-catalyzed-c-c-bond-formation-via-heteroatom-directed-1wd3dm1jdi.pdf

Rhodium-Catalyzed C-C Bond Formation via Heteroatom-Directed C-H Bond Activation

Green Chemistry is a relatively new emerging field that strives to work at the molecular level to achieve sustainability. The field has received widespread interest in the past decade due to its ability to harness chemical innovation to meet environmental and economic goals simultaneously. Green Chemistry has a framework of a cohesive set of Twelve Principles, which have been systematically surveyed in this critical review. This article covers the concepts of design and the scientific philosophy of Green Chemistry with a set of illustrative examples. Future trends in Green Chemistry are discussed with the challenge of using the Principles as a cohesive design system (93 references).

Green Chemistry: Principles and Practice

N-Heterocyclic Carbenes in Late Transition Metal Catalysis

Since nanoparticles are taken up into cells by endocytosis, phagocytosis, or pinocytosis, they have been studied as intracellular drug carriers. Janus particles have an anisotropic structure composed of two or more distinct domains and have been proposed for use in various applications, including use as imaging agents or nanosensors. This study aimed to clarify the influence of the type of nanoparticles on their distribution in a human Caucasian colon adenocarcinoma (Caco-2) cell monolayer. We fabricated Janus and conventional spherical nanoparticles composed of pharmaceutically applicable ingredients. Janus and spherical nanoparticles composed of a cationic polymer and surfactant lipids were prepared by controlling the solvent removal pattern from the oil phase in the solvent removal process using the solvent evaporation and solvent diffusion methods. The distribution of nanoparticles in the Caco-2 cell monolayer was then evaluated using confocal laser microscopy. The mean hydrodynamic size of the fabricated Janus nanoparticles was 119.2 ± 4.6 nm. Distribution analysis using Caco-2 cells suggested that Janus nanoparticles were localized around the adherens junctions located just below the tight junction. Clear localization was not observed in non-Janus nanoparticles with the same composition. The clear localization of the Janus nanoparticles around the adherens junction may be due to their positive charge and asymmetric structure. Our results suggest the considerable potential for the development of nanoparticulate drug carriers to target cellular gaps.

Targeting cellular gaps using Janus nanoparticles containing cationic polymers and surfactant lipids.

N-Sulfonyl-1,2,3-triazoles react with thioesters in the presence of a rhodium(II) catalyst to produce β-sulfanyl enamides in a stereoselective manner. The reaction proceeds through generation of an α-imino rhodium carbene complex, nucleophilic addition of the sulfur atom of a thioester onto the carbenoid carbon atom, and subsequent intramolecular migration of the acyl group from the sulfur atom to the imino nitrogen atom. The method is successfully applied to a ring-expansion reaction of thiolactones, thus leading to the formation of sulfur-containing lactams.

A Reaction of Triazoles with Thioesters to Produce β‐Sulfanyl Enamides by Insertion of an Enamine Moiety into the Sulfur—Carbonyl Bond.

The allylation of alkynylborates (I) followed by reaction of the intermediate alkenylboranes with acetic acid leads to mixtures of E- and Z-alkenes.

Palladium-Catalyzed Allylation Reaction of Alkynylborates.

The use of harmful solvents during the preparation of pharmaceutical formulations is restricted to preserve environment and ensure safety of industrial operations. However, harmful solvents must be used to produce certain formulations. For instance, methylene chloride has been used in the fabrication of polylactic acid (PLA) and poly(lactic-co-glycolic) acid (PLGA) microspheres. This review highlights the latest advances in the strategy of PLA or PLGA microsphere production from non-halogenated solvents and describes advantages and limitations of these methods. The study also discusses the development of dry fabrication techniques for microsphere fabrication and the positioning of conventional and dry fabrication in the containment concept for workers' safety.

https://www.jstage.jst.go.jp/article/ddt/advpub/0/advpub_2023.01008/_pdf

Harmless and ecologically acceptable fabrication of long-acting injectable microspheres.

Sclerosing encapsulating peritonitis (SEP) is a rare clinical syndrome characterised by fibrosis and thickening of the peritoneum with massive adhesions of the abdominal organs. In humans, abdominal tumours, such as pancreatic adenocarcinoma, can be underlying diseases of SEP. This report describes a case of SEP in a dog with pancreatic ductal adenocarcinoma.An 11-year-old male neutered French Bulldog presented with chronic vomiting. Ultrasonography revealed a mass in the centre of the abdomen. A small amount of ascites, interpreted as modified transudate, was present in the abdominal cavity. Computed tomography (CT) revealed peritoneal effusion with a thickened peritonium. Laparoscopy revealed a large nodular lesion occupying the central portion of the abdomen, continuous with the falciform ligament. Histological examination of the biopsy specimens of the mass, abdominal wall, and gastric peritoneum revealed marked fibroplasia with mild lymphoplasmacytic infiltrates. Based on these results, a tentative diagnosis of early stage sclerosing encapsulating peritonitis (SEP) was made. Prednisolone and tamoxifen were administered with the expectation of ameliorating SEP, however, the dog died 61 days post diagnosis. At autopsy, the intestinal loop and mesentery were encased in the fibrous membrane, which is a typical finding in SEP. Histopathology and immunohistochemistry of the samples obtained at autopsy supported the diagnosis of pancreatic ductal adenocarcinoma with peritoneal dissemination and distant metastasis with desmoplasia. The unexpectedly hardened skin, where previously laparoscopic ports were inserted, histologically contained the same carcinoma cells with desmoplasia.To the best of our knowledge, this is the first report of canine SEP with pancreatic ductal adenocarcinoma that also caused metastasis to port insertion sites as well as distant organs. 

/pdf/sclerosing-encapsulating-peritonitis-in-a-dog-with-3pv78j47.pdf

Masahiro Murakami

Papers

Targeting cellular gaps using Janus nanoparticles containing cationic polymers and surfactant lipids.

A Reaction of Triazoles with Thioesters to Produce β‐Sulfanyl Enamides by Insertion of an Enamine Moiety into the Sulfur—Carbonyl Bond.

Palladium-Catalyzed Allylation Reaction of Alkynylborates.

Harmless and ecologically acceptable fabrication of long-acting injectable microspheres.

Sclerosing encapsulating peritonitis in a dog with pancreatic ductal adenocarcinoma