Efficient synthesis of pentasubstituted pyrroles via one-pot reactions of arylamines,acetylenedicarboxylates, and 3-phenacylideneoxindoles

An efficient synthetic method for the pentasubstituted pyrroles was successfully developed via the one-pot domino reactions of arylamines, acetylenedicarboxylates, and 3-phenacylideneoxindoles. The reaction mechanism involved the sequential Michael addition and ring closure of the in situ generated β-active enamino ester.     

Cadmium(II)–Triazole Framework as a Luminescent Probe for Ca2+ and Cyano Complexes

A bidentate ligand, 1‐{4‐[4‐(1H‐1,2,4‐triazol‐1‐yl)phenoxy]phenyl}‐1H‐1,2,4‐triazole (TPPT), has been designed and synthesized. By using TPPT as a building block for self‐assembly with Cd(NO₃)₂ ? 4 H₂O and CdCl₂ ? 10.5 H₂O, novel 1D double‐chain {[Cd(TPPT)(NO₃)₂] ? 3 H₂O}_n ( 1 ) and 2D (4,4) layer [Cd(TPPT)Cl₂(H₂O)]_n ( 2 ) have been constructed. When 1 was employed as a precursor and exposed to DMF or N,N′‐dimethylacetamide (DMAC), the crystals of 1 dissolved and reassembled into two types of brown block‐shaped crystals of 1D double chains: {[Cd(TPPT)₂(NO₃)₂] ? DMF}_n ( 1 a ) and {[Cd(TPPT)₂(NO₃)₂] ? DMAC}_n ( 1 b ). The anion‐exchange reactions of complex 2 have also been investigated. After gently stirring crystals of 2 in CHCl₃/C₂H₅OH/H₂O containing NaBr, NaI ? 2 H₂O, or NaOAc ? 3 H₂O, the crystals retained their crystalline appearances. A remarkable single crystal to single crystal transformation was observed and 1D double chains of {[Cd(TPPT)Br₂] ? C₂H₅OH}_n ( 2 a ) and {[Cd(TPPT)₂I₂] ? CHCl₃}_n ( 2 b ), and 1D single chains of [Cd(TPPT)(H₂O)₂(CH₃COO)₂]_n ( 2 c ), can be obtained. Luminescent properties indicate that 1 shows excellent selectivity for Ca²⁺ and cyano complexes. To the best of our knowledge, this is the first example of a luminescent probe for Ca²⁺ based on triazole derivatives.     

Structure–activity relationships of anthocyanidin glycosylation

This paper summarizes the main achievements about the structure–activity relationships of anthocyanidin glycosylation. Anthocyanidin glycosylation is the essential step of anthocyanin biosynthesis and also the prerequisite of the further modifications of anthocyanins, which is jointly characterized by the glycosylation site, the type and number of the glycosyl as well as the glycosidic bond type. It generally enhances the stability, results in the hypsochromic effect and blueing, decreases the bioavailability and anticancer activity, and decreases, increases, or does not change the antioxidant activity of the anthocyanidins or anthocyanins, which is synergetically determined by the glycosylation site and the type and number of the glycosyl. Thereinto, in nature, the blue hues caused by the glycosylation may also be reinforced by the formation of the anthocyanic vacuolar inclusions. This review could provide a reference for the research of the structure-optimizing and function-exploiting of anthocyanins.     

A Hexagonal Covalent Porphyrin Framework as an Efficient Support for Gold Nanoparticles toward Catalytic Reduction of 4‐Nitrophenol

A hexagonal porphyrin‐based porous organic polymer, namely, CPF‐1, was constructed by 3+2 ketoenamine condensation of the C₂‐symmetric porphyrin diamine 5,15‐bis(4‐aminophenyl)‐10,20‐diphenylporphyrin and 1,3,5‐triformylphloroglucinol. This material exhibits permanent porosity and excellent thermal and chemical stability. CPF‐1 can be employed as a superior supporting substrate to immobilize Au nanoparticles (NPs) as a result of the strong interactions between Au NPs and the CPF support. An Au@CPF‐1 hybrid was synthesized by an interfacial solution infiltration method with NaBH₄ as reducing agent. Au NPs (5 nm) grew on CPF‐1 and were distributed without aggregation. Moreover, Au@CPF‐1 exhibits superior catalytic activity compared to many other reported Au‐based catalysts for the reduction of 4‐nitrophenol in the presence of NaBH₄. In addition, Au@CPF‐1 has excellent stability and recyclability, and it can be reused for three successive reaction cycles without loss of activity. The dense distribution of phenyl rings on the channel walls of the CPF support can reasonably be regarded as the active sites that adsorb the 4‐nitrophenol molecule through hydrogen‐bonding and C?H ??? π interactions, as was confirmed by the X‐ray structure of model compound DAPP‐Benz.     

(3S,4S)-4-氨基-3-羟基-6-甲基庚酸的合成

价廉易得的L-亮氨酸先以苄基同时保护氨基及羧基得(S)-2-(二苄胺基)-4-甲基戊酸苄酯,进而在碱性条件下与乙腈发生亲核取代反应得(S)-4-(二苄胺基)-6-甲基-3-氧代庚腈,再经硼氢化钠选择性还原羰基得(3S,4S)-4-(二苄胺基)-3-羟基-6-甲基庚腈,用双氧水氧化得(3S,4S)-4-(二苄胺基)-3-羟基-6-甲基庚酸,最后在Pd(OH)2/C-H2作用下脱掉苄基得到(3S,4S)-4-氨基-3-羟基-6-甲基庚酸,即(3S,4S)-statine。整个合成路线总产率为33.6%。     

Vertically aligned γ-AlOOH nanosheets on Al foils as flexible and reusable substrates for NH<Subscript>3</Subscript> adsorption

Vertically aligned γ-AlOOH nanosheets (NSs) have been successfully fabricated on flexible Al foils via a solvothermal route without morphology-directing agents. Three different reaction temperature (25, 80, and 120 ?C) and time (30 min, 45 min, and 24 h) are discussed for the growth period, which efficiently tune the density and size of the γ-AlOOH NSs. Meanwhile, the growth speed of the nanosheets confirms that dominant growth stage is seen in the initial 45 min. Furthermore, the interlayer of the γ-AlOOH NSs displays an average height of 140 nm and superhydrophilicity. By dynamic adsorption, the assynthesized γ-AlOOH NSs exhibit an outstanding NH₃ adsorption capacity of up to 146 mg/g and stably excellent regeneration for 5 cycles. The mechanism of NH₃ adsorption on the in-plane of the γ-AlOOH NSs is explained by the Lewis acid/base theory. The H-bond interactions among the NH₃ molecules and the edge groups (-OH) further improve the capture ability of the nanosheets.