A three-component annulation reaction was developed for the synthesis of pyrroles, a class of compounds with various properties valuable to biomedical and polymer industries. Treatment of α-silylaryl triflates, Schiff bases, and alkynes generated polysubstituted pyrroles in good yields (61–86%) with regioselectivity. This domino reaction involved completion of five sequential steps in a single flask, which comprised aryne formation through 1,2-elimination, their alkylation by Schiff bases through 1,2-addition, 1,4-intramolecular proton transfer, Hüisgen 1,3-dipolar cycloaddition, and dehydrogenative aromatization. It was then successfully applied as the key step in the synthesis of the natural product lamellarin R. This new reaction represents an efficient, sustainable process for the production of chemical materials.

The purpose of this paper is to introduce the notion of sum-matroid and to link it to the theory of sum-rank metric codes. Sum-matroids generalize both the notions of matroid and q-matroid. We show how generalized weights can be defined for them and establish a duality for these weights analogous to Wei's one for generalized Hamming weights of linear codes, and more generally, for matroids proved by Britz et al. We associate a sum-matroid to a sum-rank metric code and the corresponding results of Martínez-Peñas for sum-rank metric codes are derived as a consequence.

Synthetic application of arynes is broadened by their reactions with neutral N-, Sand nd O-containing nucleophiles to produce three types of compounds. Accordingly, 1,2-dihydroquinolines are synthesized from Schiff bases, alkynes, and arynes through a Diels-Alder reaction. Epoxides are prepared from thioethers and arynes along with aldehydes or ketones through a Johnson-Corey-Chaykovsky reaction. Phenolic ethers are produced from allyl ethers and arynes through a Claisen-type rearrangement. These target molecules, including natural products γ-asarone, asaricin, and a cholesteryl phenolic ether, are formed through reactions initiated by arynes. These new reactions share a prevailing feature of domino processes, which are carried out in a single flask and afford the desired products in good to high yields.

Production of chiral compounds by green processes like domino reactions is of importance to environmental protection and sustainable development. Nevertheless, finding an appropriate catalyst to control enantioselectivity with satisfaction is a major challenge. Here, we report the accomplishment of a newly developed domino reaction for synthesizing optically active 3-pyrrolines, a class of compounds with various biological properties. The reaction involves the use of (trimethylsilyl)aryl triflates, Schiff bases, and alkynes in the presence of a chiral catalyst (R)-(À )-1,1'binaphthyl-2,2'-diyl hydrogenphosphate. The key features of this new reaction include the generation of a single product in very good yields (75-85%) with high stereo-and enantioselectivity; the enantiomeric ratio reaches as high as 98.5 : 1.5. Moreover, it involves an aryne-induced domino reaction and an unusual 1,4-intramolecular proton transfer, which overwhelms the well-established 1,5-proton transfer.

GPI-anchored folate receptor α (FRα) is an attractive anticancer drug target and diagnosis marker in fundamental biology and medical research due to its significant expression on many cancer cells. Currently, analyses of FRα expression levels are usually achieved using immunological methods. Due to the continual FRα synthesis and degradation, immunological methods are not suitable for studying real-time dynamic activities of FRα in living cells. In this paper, we introduce a rapid and specific FRα protein-labeling fluorescent probe, FR1, to facilitate the study of the dynamics of expression and degradation processes of endogenous FRα in living cells. With this labeling probe, insights on FRα protein lifetime and shedding from the cell surface can be obtained using fluorescence live-cell imaging and electrophoresis techniques. We revealed that FRα undergoes soluble domain release and endocytosis degradation simultaneously. Imaging results showed that most of the membrane FRα are transported to the lysosomes after 2 h of incubation. Furthermore, we also showed that the secretion of a FRα soluble domain into the environment is most likely accomplished by phospholipase. We believe that this protein-labeling approach can be an important tool for analyzing various dynamic processes involving FRα.

No abstract

The modern world has no available drugs for the treatment of enteroviruses (EV), which affect millions of people worldwide each year. The EV71 is a major causative disease for hand, foot, and mouth disease; sometimes it is associated with severe central nervous system diseases. Treatment for enteroviral infection is mainly supportive; treatment for aseptic meningitis caused by enteroviruses is also generally symptomatic. Upon the urgent request of new anti-enterovirus drugs, a series of hinged aromatic compounds with polynulei were synthesized through two different chemical pathways. Among these morpholine–furan/thiophene/pyrrole–benzene–pyrazole conjugates, three new agents exhibited inhibitory activity with EC50 = 2.29–6.16 μM toward EV71 strain BrCr in RD cells. Their selectivity index values were reached as high as 33.4. Their structure–activity relationship was deduced that a thiophene derivative with morpholine and trifluorobenzene rings showed the greatest antiviral activity, with EC50 = 2.29 μM.

A new domino reaction is developed for the synthesis of optically active 3‐pyrrolines. The reaction involves the use of (trimethylsilyl)aryl triflates, KF, Schiff bases, and alkynes in the presence of a chiral catalyst (R)‐(–)‐1,1′‐binaphthyl‐2,2′‐diyl hydrogenphosphate. The key features of this reaction include the generation of a single product in very good yields with high stereo‐ and enantioselectivity. The enantiomeric ratio reaches as high as 98.5:1.5. The overall pathway includes four steps in a domino process of 1,2‐elimination, 1,2‐nucleophilic addition, 1,4‐proton shift, and (3+2) cycloaddition. More information can be found in the Full Paper by Jih Ru Hwu et al.