Search

A copper(II)-catalyzed protocol for the construction of aminothioalkenes has been achieved that is based on the reaction of enaminones with disulfides/thiophenols in the presence of tert-butyl hydroperoxide (TBHP) to give good to excellent yields. This study provides a new strategy for the formation of C(sp2)−S bonds via direct α-sulfenylation of C(sp2)−H bonds.

Two complementary cascade cyclization reactions were described, namely KHSO4-promoted [1+2+3] cyclization and TMSCl-promoted four-molecular cascade cyclization for the concise synthesis of highly functionalized spirooxindoles in excellent yields. Between them, the improved TMSCl-promoted cyclization reaction of isatins, N,N-dimethylenaminones and amines was carried out to afford various desired products under milder conditions. The observed chemoselectivity of new TMSCl-promoted cyclization mechanism was reasonably explained by designing the intermediate bis-enaminones. Furthermore, the gram-scale synthesis and the synthetic applications were also evaluated.

An efficient and practical method has been developed for the divergent synthesis of N-arylenaminones and 3-aroylquinolines from 2-aminoaryl ketones and N,N-dimethylenaminones in the presence of 4-toluenesulfonic acid through synergistic control of the temperature and amount of catalyst. Furthermore, gram-scale synthesis and synthetic applications have been evaluated. Features of this protocol include controllable results, mild conditions, good functional-group tolerance, operational simplicity, and excellent yields.

The Mn(OAc)3-promoted oxidative phosphonylation of N,N-dimethylenaminones with H-phosphonates, involving a chemo- and regioselective Csp2-Csp2 bond cleavage and Csp3-P bond formation in one step, provided successfully functionalized β-ketophosphonates under mild reaction conditions. Oxidative Csp3-H/P-H cross-coupling reactions via Csp3-C(C═O) bond cleavage and mechanistic studies are conducted preliminarily, and a possible mechanism is proposed. This novel method proceeds in good to excellent yields, shows operational simplicity, broad substrate scope, and large-scale preparation.

The Mn(OAc)

In the present work, reduction of Cr(VI) induced by UV–visible light in aqueous solution was investigated. The aqueous medium contained TiO2 nanosheets and no additional reducing agents or hole scavengers. A hydrothermal method was used to synthesize fluorinated TiO2 nanostructures with various percentages of exposed {001} facets and initial F/Ti ratios. Fluorine-free TiO2 nanosheets were obtained by washing the TiO2 samples with NaOH solution. The surface fluorination facilitates the adsorption process by increasing the number of surface OH groups generated. Moreover, fluorination efficiently inhibits the recombination of photogenerated electron–hole pairs. The {001} facets have an indirect role in the photocatalytic reduction of Cr(VI) because oxidative dissolution of H2O occurring on {001} facets and Cr(VI) reduction occurring on {101} facets are simultaneous reactions. The optimal ratio of exposed {001} to {101} was found to be ∼72:18.

Pulsatilla chinensis is a medicinal root plant that has been used to treat a wide range of disease conditions. Our study determined the antiprotozoal activity of various P. chinensis extracts and fractions against Giardia intestinalis including their effects on parasite growth, cell viability, adherence, and morphology. Ethyl acetate extracts (IC50 = 257.081 μg/ml) were the most active to inhibit the growth of G. intestinalis followed by aqueous extract (PWE), saponins, and n-butanol extract. The PWE and ethyl acetate extract inhibited G. intestinalis trophozoites adherence after 3 h of incubation and killed almost 50 % of the parasite population in a time-dependent manner. Changes in morphology, presence of precipitates in the cytoplasm, dissolved cytoplasm with large vacuole, break of flagella and ventral disk, membrane blebs, and intracellular and nuclear clearance of the treated trophozoites were observed by scanning and transmission electron microscopy. We demonstrated that P. chinensis induced these changes in G. intestinalis morphology and consequently has potential therapeutic use against giardiasis.

The telomerase reverse transcriptase (TERT) is primarily known for its ability to elongate telomeres for maintaining chromosomal integrity and delaying cellular senescence. It plays an important role in cell proliferation, differentiation, tumorigenesis, and aging. Telomerase includes two core components—an internal RNA moiety acting as a template of DNA extension and a catalytic subunit (TERT) which provides catalytic activity. Here, we described the cloning, sequence, and characterization of the TERT gene from Trichinella spiralis (T. spiralis). The prediction results of amino acid sequence showed that it possessed all the motifs characteristics of the TERT family members. T. spiralis TERT (Ts_TERT) cDNA contains an open reading frame encoding a protein with 1,201 amino acids with moleculer mass of 139 kDa and isoelectric point of 9.673, and the protein contains the conserved reverse transcriptase motifs 1, 2, A, B, C, D, and E, as well as the TERT-specific T motifs and the N-terminal conserved motifs GQ, CP, and QFP. While RT-PCR analysis indicates that TERT mRNA is expressed in T. spiralis adult worm, newborn larvae, and muscle larvae.

Giardia canis virus (GCV) is a double-stranded RNA (dsRNA) virus of the family Totiviridae. In this study, the full length cDNA of the G. canis virus was constructed in pPoly2/sfinot vector and RNA was transcribed in vitro. Virus-free G. canis trophozoites were transfected with in vitro transcribed GCV RNA by electroporation. Transfected trophozoites were cultured for 12, 24, 36, 48, 60, or 72 h post transfection for analysis. The ultrastructures of the transfected trophozoites were determined by transmission electron microscopy. The viral particles were detectable sporadically in the cytoplasm as early as 24 h post transfection, but became evident and wide-spread 36 h post transfection. The number of viral particles increased dramatically from 48 to 60 h. Viral particles were released into the culture medium starting at about 60 h and detectable in nuclei 72 h post transfection. Severe vacuolization was seen in transfected G. canis trophozoites as early as 36 h post transfection and persisted throughout the course of this study. The results of the present study indicate that in vitro transcribed GCV transcripts were capable of infecting Giardia trophozoites, apparently replicated and packaged into mature infectious viral particles which were released from the host.