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Graphical abstract Highlights • Microwave-assisted approach to nitrophenyl pyrabactin analogues. • Excellent yields (91%–97%) and broad substrate scope. • Very suitable to prepare flusulfamide (fungicide). • Enhancing POD activity in response to heavy metal stress. Abstract A facile and efficient approach to N -(2-nitrophenyl) benzenesulfonamides was developed under microwave irradiation. A series of pyrabactin analogues containing nitrophenyl scaffold was obtained in excellent yields. In addition, the method was pretty suitable to prepare flusulfamide. Significantly, the 3ae could enhance POD activity in response to heavy metal stress. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

[Display omitted] • Unique synthons. • Extremely simple and mild reaction conditions. • New chiral spirooxindole imine. • Almost all the prepared chiral molecules with at least > 90%ee and final to 99%ee. • The target molecule may be used as potential organocatalysts/ligands and potential new chemical entities. A new type of spiro[pyrrolinyl-3,2′-oxindole] scaffolds were effectively prepared from an enantioselective Michael/cyclization between a crucial synthon of 3-(diphenylmethylene)-amino oxindole and acrolein catalyzed by a cinchona alkaloid in up to 99% total yield with up to 99% ee. Those spirooxindole aldehyde imines were reduced to new kinds of prolineamide like spirooxindole chiral amine organocatalysts. The reaction has been successfully scaled up to a gram scale and most typical organocatalysts were further purified up to 99% ee by recrystallization in their hydrochloride salts. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis and structures of two pairs of novel enantiopure inherently chiral calix[4]arene-derived salphen ligands were described. Several Zn2+, Ni2+, and Cu2+ complexes of the chiral ligands were also prepared, and their structures were characterized by NMR, IR, CD, and HRMS spectra. [Copyright &y& Elsevier]

Abstract: Two boronic acid-based fluorescent chemosensors in C 3 symmetry have been prepared with a facial method. These compounds show remarkable ability to recognize α-hydroxycarboxy acids and sugar acids over most saccharides. The fluorescence intensity of the receptors decreased obviously upon adding the α-hydroxy acids in a pH 8.71 buffer of methanol–water, which can be explained with the internal charge-transfer (ICT) mechanism. [Copyright &y& Elsevier]

Abstract: Reactions of indoles and α,β-unsaturated ketones could be effectively catalyzed by using 10mol% gallium triiodide to give the corresponding Michael adducts in good to excellent yields. [Copyright &y& Elsevier]

Abstract: The 2,3-disubstituted 1,4-benzoquinones were synthesized through the regioselective addition of 4-hydroxycoumarins with 1,4-benzoquinone in aqueous acetone, which were different from 2,5-disubstituted adducts generated by the previously reported reaction of compounds possessing an activated methylene with 1,4-benzoquinone. [Copyright &y& Elsevier]

Abstract: Unique structures of novel ionophores of double-armed penta-crown ethers were successfully synthesized. Diaza 18-crown-6 was designed as the parent crown ring. The penta-crown ethers were prepared by the reaction of trimethylolpropane triacrylate (TMPTA) with diaza 18-crown-6 and further with 1-aza crown ethers through the Michael reaction. The newly synthesized penta-crown ethers were characterized by 1H NMR, 13C NMR, FAB mass spectrum, IR and elemental analyses, respectively. [Copyright &y& Elsevier]

Abstract: Unique structures of tetra-crown ethers were successfully synthesized by the reaction of tetramethylolmethane tetraacrylate (TMMT) reacted with crown ethers containing primary amine functional group such as 2-aminomethyl crown ethers and 4-aminobenzo crown ethers; containing secondary amine group like 1-aza crown ethers through Michael reaction. The newly synthesized tetra-crown ethers were characterized by 1H NMR, 13C NMR, FAB mass spectrum, elemental analyses, IR, respectively. [Copyright &y& Elsevier]

Abstract: Facile, mild and efficient one-pot preparation of N α-Fmoc-N ε-(benzyl, methyl)-lysine, a building block for monomethylated peptide synthesis, was described. This building block was proved to be efficient for the synthesis of site-specifically monomethylated peptide. Benzyl group, which was incorporated by reductive benzylation and removed via catalytic hydrogenolysis, served as an excellent protecting group. [Copyright &y& Elsevier]

α-Hypervalent iodo functionalized phosphonium and arsonium ylides 2 can be used as umpolung ylides to react with nucleophiles to give α-heteroatom substituted ylides 4 in good yields. A tandem sequence of nucleophilic substitution then Wittig reaction occurs smoothly to form (Z)-α-halo-α,β-unsaturated esters 6, stereoselectively, in moderate to excellent yields. [Copyright &y& Elsevier]

Abstract: Larger-rim functionalized tetraoxacalix[2]arene[2]triazine host molecules were efficiently synthesized through a fragment coupling followed by AlCl3-mediated deprotection/arylation protocol. Substituent effects, functions of counter cations on anion recognition in solution were systematically studied by means of fluorescence and NMR titrations. [Copyright &y& Elsevier]

Abstract: Functionalized N,O-bridged calix[1]arene[4]pyridines, first examples of the odd-numbered heterocalixaromatics containing mixed heteroatom bridges and mixed aromatic units, have been synthesized from the Pd2(dba)3/dppp-catalyzed 2+3 macrocyclic fragment coupling reaction between readily available staring materials. These novel macrocyclic compounds, which adopted distorted 1,3-alternate conformation in solid state, were powerful host molecules able to form 1:1 complex with fullerene C60 in solution, giving binding constant up to 49,494M−1. [Copyright &y& Elsevier]

Abstract: Condensation reactions of o-phenylenediamine and two equivalents of acetophenone under gallium(III) triflate catalysis produce biaryl-substituted 1,5-benzodiazepines. Similar reactions of o-phenylenediamine or o-aminothiophenol and o-hydroxy chalcones lead to formation of functionalized 1,5-benzodiazepines and 1,5-benzothiazepines in good to excellent yields. The ortho-hydoxy group of chalcones is crucial for this unprecedented condensation process. [Copyright &y& Elsevier]

Abstract: The chemoselective reduction of several structurally diverse compounds containing carbonyl groups was achieved in the presence of low-valent titanium reagents. This novel synthetic method provides easy access to highly selective reduction of carbonyl groups, and possesses several advantages including one-step procedure, convenient manipulation, good to excellent yields, and short reaction times. [Copyright &y& Elsevier]

Abstract: The first single crystal X-ray analysis of the heterodimer of tetraaryl- and tetratosylurea calix[4]arenes was reported, which revealed the real pattern of the hydrogen bonds. Moreover, the heterodimer showed good encapsulation abilities for some organic molecules in CDCl3. [Copyright &y& Elsevier]

Abstract: A series of novel calix[4]arenocrowns 1a–c were efficiently synthesized by a one-pot reaction of calix[4]monohydroquinone diacetate 5 with ditosylate 6 and its analogues in the presence of sodium hydroxide. It was found that the calix[4]arenocrowns could form stable pseudorotaxane-type complexes 2a–c with paraquat, and further self-assemble into calix[4]areno[2]catenanes 3a–c with dicationic salt 8 and p-bis(bromomethyl)benzene. [Copyright &y& Elsevier]

Abstract: Seventeen unsymmetrical curcumin derivatives were synthesized in good yield and purity by a facile solid phase synthesis strategy. [Copyright &y& Elsevier]

Abstract: A new chemosensor was synthesized by the alkylation of p-tert-butyl-calix[4]arene with three N,N-diethylacetamide groups and one methyl 3-ethoxy-naphthalene-2-carboxylate, which exhibited highly selective fluorescent response to Pb2+ over alkali, alkali earth metal ions and some transition metal ions in CH3CN–H2O. [Copyright &y& Elsevier]

Abstract: Oxidation coupling of 3-hydroxy-4(1H)-pyridinone with β-dicarbonyl compounds led to unexpected dihydrofuro[b]-pyridinone derivatives, indicating an alternative pathway other than that with anilines or thiols. By this strategy, six novel dihydrofuro[b]-pyridinone derivatives were synthesized. [Copyright &y& Elsevier]

Abstract: A novel bridged fluorescent calix[4]arene with 1,8-diaminoanthracene and glycine at the upper rim has been prepared, which exhibited selective recognition towards AcO− over other anions such as F−, Cl−, Br−, , , I− and by fluorescence spectroscopy and 1H NMR method. [Copyright &y& Elsevier]

A new fluorescent probe based on calix[6]arene functionalized with three naphthoic acid groups was synthesized and showed selective fluorescence enhancement in the presence of La3+ and Y3+. In addition, the fluorescence enhancement behaviors depended on the pH values of the solution. [Copyright &y& Elsevier]

A new C-linked peptidocalix[4]arene functionalized with four l-alanine and dansyl units at the upper rim has been prepared, which exhibited highly selective recognition towards F- along with weaker complexation to AcO- and H2PO4- and no complexation to Cl-, Br-, I-, and HSO4- by fluorescence spectroscopy and 1H NMR method. [Copyright &y& Elsevier]

A new fluorescent chemosensor with imidazole as ionophore was synthesized by the selective derivation of calixarene, which can effectively recognize Cu2+ and Zn2+ leading to different fluoroscopic behaviors in CH3OH–H2O. This system could be considered as a molecular switch. By modulating the pH of the solution, on–off–on fluorescent switching is carried out upon combinatory addition of acid, base and Cu2+. [Copyright &y& Elsevier]

A novel fluorescent compound derived from calixarene which possesses two 3-alkoxy-2-naphthoic acid moieties has been synthesized in moderate yield. In H2O/CH3OH (1:1), its fluorescent intensity was quenched sharply in the presence of Cu2+ or Fe3+, and the degree of quenching was related to the pH of the solution. Other metal ions, such as Co2+, Ni2+, Zn2+, Mn2+, Mg2+ and Ba2+ did not affect its fluorescent spectra. This research may provide a new fluorescent probe for Cu2+ and Fe3+. [Copyright &y& Elsevier]