Transition-metal-catalyzed isoquinoline synthesis that profits from the strategy of chelation-assisted C−H activation has flourished over the past decade. By virtue of the directed C−H bond cleavage ...of imines, amines, amidines, oximes, hydroximoyl halides, hydrazones, or azines, diverse isoquinoline derivatives have been accessed from alkynes, conjugated dienes, or diazo compounds under the catalysis of rhodium, ruthenium, palladium, nickel, or manganese. This digest summarizes the annulation reactions via chelation-assisted C−H activation leading to isoquinolines, isoquinolinium salts, or isoquinoline N-oxides.
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•Four new peptides 1–4 were isolated from Aspergillus sp. SCSIO 41501.•Their structures were elucidated by spectroscopic analysis and Marfey’s method.•Compounds 1 and 2 showed evident ...antiviral activity against HSV-1.
A new cyclic pentapeptide and three new linear peptides, namely, aspergillipeptides D–G (1–4), were isolated from a culture broth of marine gorgonian-derived fungus Aspergillus sp. SCSIO 41501. Their structures were elucidated by spectroscopic analysis, and their absolute configurations were confirmed by Marfey’s method. Compounds 1 and 2 showed evident antiviral activity against herpes simplex virus type 1 (HSV-1) with IC50 values of 9.5 and 19.8µM under their non-cytotoxic concentrations against a Vero cell line, respectively, and 1 also had antiviral activity against acyclovir-resistant clinical isolates of HSV-1.
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•Au Cavitands display different reactivity than electronically similar Au complexes.•Complimentary substrates for binding have limited reactivity with Au Cavitands.•Au Cavitand’s ...inwardly directed reactive site give rise to new selectivity rules.
With an inwardly directed reactive center and a well-defined binding pocket, Au(I) functionalized resorcin4arene cavitands have been shown to catalyze molecular transformations. The reactivity profiles that emerge differ from other Au(I) catalysts. The added constraint of a binding pocket gives rise to the possibility that the substrates might have to fit into the resorcinarene pocket; our hypothesis is that substrates that match the available space have different reaction outcomes than those that do not. Herein we report on the intramolecular cyclization of alkyne-aromatic substrates with variable alkynes and aromatic composition. We see that scaffold size most drastically dictates reactivity, especially when the substrate’s features are particularly designed. The results of these experiments add to the veritable goldmine of information about the selectivity in catalysis that cavitands offer.
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•3-(Phenethylamino)demethyl(oxy)aaptamine (1) was isolated from marine sponge of Aaptos sp.•Compound 1 was a potent antimicrobial agent against dormant state of Mycobacterial ...bacilli.•Compound 1 was effective against M. tuberculosis including drug resistant strains.•The total syntheses of 1 and 3-aminodemethyl(oxy)aaptamine were successfully accomplished.
3-(Phenethylamino)demethyl(oxy)aaptamine (1) was re-discovered from the marine sponge of Aaptos sp. as an anti-dormant mycobacterial substance through the bioassay-guided separation. Compound 1 showed potent anti-microbial activity against Mycobacterium bovis BCG with a minimum inhibitory concentration of 0.75 µg/mL under both aerobic conditions and hypoxic conditions inducing dormant state. Compound 1 was also effective against pathogenic M. tuberculosis strains including clinical multidrug-resistant strains. Furthermore, the successful total syntheses of 1 and its analog 3-aminodemethyl(oxy)aaptamine (2) afford sufficient quantities for further biological studies.
An efficient heterogeneous Pd(II) azo complex catalyst for Suzuki and Sonogashira cross-coupling reaction has been developed. The catalyst showed an excellent activity for these reactions in water ...medium under aerial conditions.
A new polystyrene anchored Pd(II) azo complex has been synthesized and characterized. The present Pd(II) azo complex behaves as a very efficient heterogeneous catalyst in the Suzuki coupling and Sonogashira coupling reaction in water medium. Aryl halides, coupled with phenylboronic acids (Suzuki–Miyaura reaction) or terminal alkyne (Sonogashira reaction), smoothly afford the corresponding cross-coupling products in excellent yields (83–100% yield for Suzuki reaction and 68–96% yield for Sonogashira reaction of aryl halides) under phosphine-free reaction conditions in the presence of polystyrene anchored Pd(II) azo complex catalyst in water medium. Furthermore, the catalyst has shown good thermal stability and recyclability. This polymer-supported Pd(II) catalyst could be easily recovered by simple filtration of the reaction mixture and reused for more than six consecutive trials without a significant loss of its catalytic activity.
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•We found phytotoxic activity of the extract of Wedelia chinensis.•A novel kaurene-type phytotoxic substance, wedelienone was isolated from the extract.•Wedelienone inhibited the ...growth of cress and timothy at concentration greater than 10 μM.
Wedelia chinensis has been widely used as a traditional medicine and several bioactive compounds have been isolated. We investigated phytotoxic property and phytotoxic substances in the species. An aqueous methanol extract of W. chinensis inhibited the growth of roots and shoots of cress. The extracts were then purified by several chromatographic runs with monitoring the inhibitory activity and a phytotoxic substance was isolated. The substance was determined by spectral data to be a novel kaurene-type compound, wedelienone. Wedelienone inhibited the growth of cress and timothy (Phleum pratense L) at concentrations greater than 10–30 μM. These results suggest that wedelienone may contribute to the phytotoxic effects caused by the extracts.
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•Pyrene-based ribbon oligomers have been synthesized through oxidative cyclizations.•Cyclodehydrogenation with different catalysts was discussed in detail.•The oligomers present a ...bright blue light emission and are clearly characterized.
A series of ladder-type graphene ribbon oligomers have been synthesized through DDQ/acid-mediated oxidative cyclization. The oligomers present a bright blue light emission, and the new oligomers were clearly characterized by NMR and MALDI-TOF.
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•Facile synthesis of pH-responsive Cy5 dyes.•Dyes responding in various pH ranges.•Structural changes in response to acidic compartments of cells.
pH-Responsive fluorescent ...pentamethine cyanine (Cy5) derivatives having nucleophilic substituents were synthesized. Cy5 derivatives 1-O having mercaptopropyl, hydroxypropyl, and aminopropyl groups on an indole nitrogen atom showed pH-dependent equilibria between a fluorescent open-ring structure (1-O) and a non-fluorescent closed-ring structure (1-C) in pH ranges 3–7, 6–7.5, and 8–9, respectively. pH-Responsive dyes 1a-C having a 1,3-thiazinane structure were easily internalized into A549 cells and converted to open-ring structure 1a-O in response to the relatively low pH of acidic compartments in the cells.
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•Phytochemical study of Saharan medicinal plant.•Two new astericunolides and one humulene were isolated.•X-ray of astericunolide I.
Three new sesquiterpene-humulenes, (−)- ...asteriscunolides I (1), J (2) and (−)-(2Z,6E,9Z)-8-oxo-1α-acetoxy-2,6,9-humulatrien-12-oic acid (3) were isolated from the leaves-flowers of the Saharan medicinal plant Asteriscus graveolens along with six known compounds. The structures of the compounds were determined on the basis of spectroscopic mono and bidimensional NMR, mass spectrometry and by single-crystal X-ray diffraction. Compounds 1–3 were evaluated for cytotoxic assay, no significant activity was detected.
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