Tandem Triphosgene-Assisted Metal-Free One-pot Preparation of Nitriles and Amides from Aldehydes and Ketones

Here we report a facile and efficient triphosgene-assisted one-pot conversion of aldehydes/ketones into nitriles/amides. The triphosgene, a kind of phosgene alternative, containing both ester linkage and chloromethyl units, easily reacts with oximes for the preparation of nitriles/amides. However, the reaction of oximes with triphosgene can’t fully convert corresponding nitriles/amides due to hydrolysis of oximes to aldehydes or ketones. Our protocol tandem proceeds smoothly without the use of organic base and metal catalysts. Diverse functionalized aromatic, aliphatic, and allylic aldehydes/ketones incorporating biomass-derived platform compounds were successfully converted to nitriles and amides in excellent yields. Compared to step-by-step reaction, this tandem strategy is characterized by multi-step reaction in one pot, mild reaction conditions, and fewer by-products.

Chloromethyl Acryl Reagents for Simple and Site-Selective Cysteine and Disulfide Modification

The generation of protein biotherapeutics with improved features compared to the synthetic drugs has received emerging interest. The conjugation of various synthetic functionalities to proteins provides access to new classes of protein conjugates, where the advantages from both the synthetic world and Nature can be combined in a synergistic fashion. Here, we reported that 2-chloromethyl acryl scaffold can serve as a simple yet versatile platform for synthesizing acrylamide or acrylate derivatives by coupling with different end-group functionalities (amino group or hydroxyl group) via a one-pot reaction. The chemical properties of the amide or ester linkage influence their inherent reactivity as bioconjugation reagents, which in turn allows synthetic customization of their features to achieve selective protein modification at cysteine or disulfide sites on demand. 2-Chloromethyl acrylamide reagents with amide linkage favors selective modification at cysteine site with high efficiency and the resultant bioconjugates exhibit superior stability compared to commonly employed maleimide-thiol conjugates. In contrast, 2-chloromethyl acrylate reagents bearing ester linkage can undergo two successive Michael reaction, allowing the selective modification of disulfides with high labelling efficiency and conjugate stability. These reagents could outperform widely applied maleimide reagents in terms of stability of the resultant bioconjugates without compromising on the ease of reagent preparation, reactivity and reaction speed. <br>

Chloromethyl Acryl Reagents for Simple and Site-Selective Cysteine and Disulfide Modification

The generation of protein biotherapeutics with improved features compared to the synthetic drugs has received emerging interest. The conjugation of various synthetic functionalities to proteins provides access to new classes of protein conjugates, where the advantages from both the synthetic world and Nature can be combined in a synergistic fashion. Here, we reported that 2-chloromethyl acryl scaffold can serve as a simple yet versatile platform for synthesizing acrylamide or acrylate derivatives by coupling with different end-group functionalities (amino group or hydroxyl group) via a one-pot reaction. The chemical properties of the amide or ester linkage influence their inherent reactivity as bioconjugation reagents, which in turn allows synthetic customization of their features to achieve selective protein modification at cysteine or disulfide sites on demand. 2-Chloromethyl acrylamide reagents with amide linkage favors selective modification at cysteine site with high efficiency and the resultant bioconjugates exhibit superior stability compared to commonly employed maleimide-thiol conjugates. In contrast, 2-chloromethyl acrylate reagents bearing ester linkage can undergo two successive Michael reaction, allowing the selective modification of disulfides with high labelling efficiency and conjugate stability. These reagents could outperform widely applied maleimide reagents in terms of stability of the resultant bioconjugates without compromising on the ease of reagent preparation, reactivity and reaction speed. <br>

Suppression of human T cell activation by derivatives of glycerol monolaurate

Glycerol monolaurate (GML), a naturally occurring monoglyceride, is widely used commercially for its antimicrobial properties. Interestingly, several studies have shown that GML not only has antimicrobial properties but is also an anti-inflammatory agent. GML inhibits peripheral blood mononuclear cell proliferation and inhibits T cell receptor (TCR)-induced signaling events. In this study, we perform an extensive structure activity relationship analysis to investigate the structural components of GML necessary for its suppression of human T cell activation. Human T cells were treated with analogs of GML, differing in acyl chain length, head group, linkage of acyl chain, and number of laurate groups. Treated cells were then tested for changes in membrane dynamics, LAT clustering, calcium signaling, and cytokine production. We found that an acyl chain with 12–14 carbons, a polar head group, an ester linkage, and a single laurate group at any position are all necessary for GML to inhibit protein clustering, calcium signaling, and cytokine production. Removing the glycerol head group or replacing the ester linkage with a nitrogen prevented derivative-mediated inhibition of protein cluster formation and calcium signaling, while still inhibiting TCR-induced cytokine production. These findings expand our current understanding of the mechanisms of action of GML and the of GML needed to function as a novel immunosuppressant.

Emerging Approaches in Intravenous Moderate and Deep Sedation

Successful pharmacological innovations that have made a difference in daily practice are rare in the world of anesthesia and sedation. After many years of research, it seems that we finally have two new drug innovations that are likely to change the paradigm of moderate and deep sedation. These are oliceridine and remimazolam. Both have been in development for over a decade. Oliceridine was synthesized in a lab as an entirely new molecule. It is a biased μ- receptor agonist that acts preferentially on the G-protein pathway (which is responsible for analgesia). At least in lower doses, it has minimal effect on the beta-arrestin pathway, which is responsible for unwanted effects of μ-opioid receptor activation such as respiratory depression and gastrointestinal dysfunction. Like any other μ- receptor agonist, it produces appropriate dose-dependent analgesia. Remimazolam is structurally similar to midazolam; however, it has an additional ester linkage that delivers the kinetics of remifentanil. As a result, while pharmacodynamically identical to midazolam, remimazolam is metabolized by ester hydrolysis and subsequently its elimination is rapid and predictable. The present review discusses the two drugs in detail with a particular emphasis on their potential role in moderate and deep sedation.

Recent advance in ester synthesis by Multi Component Reactions (MCRs): A Review

: The synthesis of ester containing heterocyclic compounds via multicomponent reaction is one of the most preferable process in the synthetic organic chemistry and medicinal chemistry. Compounds containing ester linkage have a wide range of biological application in the pharmaceutical field. Therefore, many method have been developed for the synthesis of these type of derivatives. However, some of them are carried out in the presence of toxic solvents and catalysts, with lower yields, longer reaction times, low selectivities and by-products. Thus, the development of new synthetic methods for the ester synthesis is required in the medicinal chemistry. As we know, multicomponent reactions (MCRs) are a powerful tool towards the one-pot ester synthesis, so in this article we have reviewed the recent developments in ester synthesis. This work covers selected explanation of methods via multicomponent reactions to explore the methodological development in ester synthesis.

Distinct twist-bend nematic phase behaviors associated with the ester-linkage direction of thioether-linked liquid crystal dimers

Two homologous series of thioether-linked liquid crystal dimers with oppositely directed esters, viz. CBCOOnSCB and CBOCOnSCB, exhibit largely different helical pitches in the NTB phase, which are ascribed to their molecular bend or biaxiality.

Influence of a Single Ether Bond on Assembly, Orientation, and Miscibility of Phosphocholine Lipids at the Air-Water Interface

How does a small change in the structure of a phospholipid affect its supramolecular assembly? In aqueous suspensions, the substitution of one ester linkage in DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) by an ether linkage alters its phase behaviour completely. To unravel the effect of replacing a phospholipid’s ester linkage by an ether linkage in lipid monolayers, we characterized pure monolayers of the model lipid DPPC and its sn-2 ether analogue PHPC (1-palmitoyl-2-O-hexadecyl-sn-glycero-3-phosphocholine) as well as mixtures of both by measurements of surface pressure – molecular area (π–A_mol) isotherms. In addition, we used infrared reflection absorption spectroscopy (IRRAS) and epifluorescence microscopy to study lipid condensation, lipid chain orientation, headgroup hydration, and lipid miscibility in all samples.

Influence of a Single Ether Bond on Assembly, Orientation, and Miscibility of Phosphocholine Lipids at the Air-Water Interface

How does a small change in the structure of a phospholipid affect its supramolecular assembly? In aqueous suspensions, the substitution of one ester linkage in DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) by an ether linkage alters its phase behaviour completely. To unravel the effect of replacing a phospholipid’s ester linkage by an ether linkage in lipid monolayers, we characterized pure monolayers of the model lipid DPPC and its sn-2 ether analogue PHPC (1-palmitoyl-2-O-hexadecyl-sn-glycero-3-phosphocholine) as well as mixtures of both by measurements of surface pressure – molecular area (π–A_mol) isotherms. In addition, we used infrared reflection absorption spectroscopy (IRRAS) and epifluorescence microscopy to study lipid condensation, lipid chain orientation, headgroup hydration, and lipid miscibility in all samples.