Kinetically Controlled Stereoselective Synthesis of 2-Oxo-2-aryl-1,3,2-dioxaphosphorinane Derivatives via a Palladium-Catalyzed Reaction.

Chiral phosphonate esters have been widely applied in the fields of organic chemistry, medicine, and photoelectric materials. However, it requires the challenging enantioselective synthesis of cyclic phosphonate esters with the desired chiral configuration. The two epimers of 2-oxo-2-1,3,2-dioxaphosphorinane derivatives should have different reactivities in Pd-catalyzed coupling reactions, which could lead to an effective methodology for the asymmetric synthesis of 2-oxo-2-aryl-1,3,2-dioxaphosphorinane derivatives.

Bioinspired large Stokes shift small molecular dyes for biomedical fluorescence imaging.

Long Stokes shift dyes that minimize cross-talk between the excitation source and fluorescent emission to improve the signal-to-background ratio are highly desired for fluorescence imaging. However, simple small molecular dyes with large Stokes shift (more than 120 nanometers) and near-infrared (NIR) emissions have been rarely reported so far. Here, inspired by the chromophore chemical structure of fluorescent proteins, we designed and synthesized a series of styrene oxazolone dyes (SODs) with simple synthetic methods, which show NIR emissions (>650 nanometers) with long Stokes shift (ranged from 136 to 198 nanometers) and small molecular weight (<450 daltons).

Crystal structure of SARS-CoV-2 main protease provides a basis for design of improved α-ketoamide inhibitors.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is a global health emergency. An attractive drug target among coronaviruses is the main protease (M, also called 3CL) because of its essential role in processing the polyproteins that are translated from the viral RNA. We report the x-ray structures of the unliganded SARS-CoV-2 M and its complex with an α-ketoamide inhibitor.

α-Ketoamides as Broad-Spectrum Inhibitors of Coronavirus and Enterovirus Replication: Structure-Based Design, Synthesis, and Activity Assessment.

The main protease of coronaviruses and the 3C protease of enteroviruses share a similar active-site architecture and a unique requirement for glutamine in the P1 position of the substrate. Because of their unique specificity and essential role in viral polyprotein processing, these proteases are suitable targets for the development of antiviral drugs. In order to obtain near-equipotent, broad-spectrum antivirals against alphacoronaviruses, betacoronaviruses, and enteroviruses, we pursued a structure-based design of peptidomimetic α-ketoamides as inhibitors of main and 3C proteases.

[Lead compound optimization strategy (2)--structure optimization strategy for reducing toxicity risks in drug design].

Idiosyncratic adverse drug reactions (IDR) induce severe medical complications or even death in patients. Alert structure in drugs can be metabolized as reactive metabolite (RM) in the bodies, which is one of the major factors to induce IDR. Structure modification and avoidance of alert structure in the drug candidates is an efficient method for reducing toxicity risks in drug design.

[Application of methyl in drug design].

The methyl group plays an important role in the rational drug design. Introducing methyl into small molecules has become an important strategy of lead compound optimization. The application of methyl in drug design is reviewed in this paper.

Enantioselective synthesis of 2-substitued-tetrahydroisoquinolin-1-yl glycine derivatives via oxidative cross-dehydrogenative coupling of tertiary amines and chiral nickel(II) glycinate.

The asymmetric synthesis of 2-substituted-tetrahydroisoquinolin-1-yl glycines was achieved by an oxidative cross-dehydrogenative coupling (CDC) reaction. This method for activation of the α-C-H bonds of amines with chiral nickel(II) glycinate using o-chloranil as the sole oxidant afforded highly diastereoselective coupling adducts. The decomposition of coupling adducts readily afforded 2-substituted-tetrahydroisoquinolin-1-yl glycine derivatives.

Highly diastereoselective synthesis of 3-indolylglycines via an asymmetric oxidative heterocoupling reaction of a chiral nickel(II) complex and indoles.

The asymmetric synthesis of 3-indolylglycine derivatives was achieved by an oxidative heterocoupling reaction. This method for the selective C-3 functionalization of unprotected indoles with the chiral equivalent of a nucleophilic glycine nickel(II) complex afforded adducts with high diastereoselectivities. The decomposition of adducts readily afforded 3-indolylglycine derivatives in high yields.

Synthesis of polysubstituted β-amino cyclohexane carboxylic acids via Diels-Alder reaction using Ni(II)-complex stabilized β-alanine derived dienes.

This paper describes the design and synthesis of a new class of β-alanine derived dienes stabilized by Ni(II)-complex. Preliminary study of their Diels-Alder cycloaddition reactions with several types of dienophiles demonstrates their significant synthetic potential for the preparation of various polyfunctional β-aminocyclohexane carboxylic acids.

Improved synthesis of rupintrivir.

An improved synthesis of rupintrivir (AG7088) was accomplished using three amino acids (l-glutamic acid, d-4-fluorophenylalanine, and l-valine) as the building blocks. The key fragment ketomethylene dipeptide isostere was constructed with the valine derivative and phenylpropionic acid derivative, followed by coupling with a lactam derivative and an isoxazole acid chloride to provide AG7088 totally in eight steps.

Enterovirus 71 and coxsackievirus A16 3C proteases: binding to rupintrivir and their substrates and anti-hand, foot, and mouth disease virus drug design.

Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) are the major causative agents of hand, foot, and mouth disease (HFMD), which is prevalent in Asia. Thus far, there are no prophylactic or therapeutic measures against HFMD. The 3C proteases from EV71 and CVA16 play important roles in viral replication and are therefore ideal drug targets.

Preparation of α-alkyl-β-amino acids via β-alanine Ni(II) complex.

A new β-amino acrylic acid Ni(II) complex has been developed and used for the synthesis of α-alkyl-β-amino acids via alkylation with alkyl halides under operationally convenient conditions. The pivotal α-alkylated intermediate can be converted into the corresponding α-alkyl-β-amino acids via two steps with a wide range of substituents.

Highly diastereo- and enantioselective synthesis of syn-β-substituted tryptophans via asymmetric Michael addition of a chiral equivalent of nucleophilic glycine and sulfonylindoles.

The asymmetric synthesis of syn-β-substituted tryptophan derivatives was carried out by the Michael addition of chiral equivalent of nucleophilic glycine with sulfonylindoles, and high diastereo- and enantioselectivities were achieved. The resulting adducts were readily converted to syn-β-substituted tryptophans in 96% yield, indicating that the proposed method is a highly efficient route to chiral syn-β-substituted tryptophans.

Synthesis of Pyrrolo[1,2-a]quinoxalines via gold(I)-mediated cascade reactions.

In this study, we developed an efficient tandem process of hydroamination and hydroarylation using a gold catalyst to enable and study the reactions between pyrrole-substituted anilines and alkynes. The gold(I)-catalyzed reactions were achieved in toluene at 80 °C over a reaction time of 1−6 h. These reactions are applicable to a variety of aromatic amino compounds and both the terminal and internal alkynes.

Asymmetric synthesis of sterically and electronically demanding linear ω-trifluoromethyl containing amino acids via alkylation of chiral equivalents of nucleophilic glycine and alanine.

An operationally convenient, scalable asymmetric synthesis of linear, ω-trifluoromethyl-containing amino acids, which were not previously produced in their enantiomerically pure form, has been developed via alkylation of chiral equivalents of nucleophilic glycine and alanine. The simplicity of the experimental procedures and high stereochemical outcome (yields up to 90% and diastereoselectivity up to 99%) of the presented method render these fluorinated amino acids readily available for systematic medicinal chemistry studies and de novo peptide design.

Efficient synthesis of symmetrical alpha,alpha-disubstituted beta-amino acids and alpha,alpha-disubstituted aldehydes via dialkylation of nucleophilic beta-alanine equivalent.

Homologation of the nucleophilic beta-alanine equivalent beta-Ala Ni(II)-PABP [Ni(II) complex of beta-alanine Schiff base with 2-[N-(alpha-picolyl)amino]benzophenone (PABP), 1] via alkyl halide alkylation was systematically studied as a general method for preparing symmetrically alpha,alpha-disubstituted beta-amino acids. The dialkylation reactions could be easily performed and did not require inert atmosphere, dried solvents, and low temperatures, thereby affording the benefits of operationally convenient experimental procedure and high atom economy. Further, the methodology developed by us can also be used to generate symmetrical alpha,alpha-disubstituted aldehydes through an alternative decomposition method.