Oxidation of Aromatic Amines to Quinones by Iodic Acid under Microwave Irradiation in the Presence of Montmorillonite K10 and Silica Gel

Summary. A variety of aromatic amines are oxidized to their corresponding quinones in excellent yields by supported iodic acid under microwave irradiation and solvent free conditions.     

1-Adamantanecarboxylic Acid Esters of Certain Terpenols, Sterols, and Plant Phenols

Esters 1b-15b were prepared from cetyl alcohol 1a, terpenols 2a-6a, sterols 7a-10a, plant phenols 11a-13a, and alcohols 14a-15a by reaction with 1-adamantanecarboxylic acid chloride in the presence of pyridine.     

Thermal degradation of the polymer obtained by oxidation of C60 fullerene by oleum

Degradation of (C₆₀) _n polymer and the C₁₂₀ and C₁₂₀O dimers at different temperatures was studied by IR and ESR spectroscopy. The formation of C₆₀ was revealed. The polymer stability was found to be higher than the stability of the dimers. Peculiar features of the IR spectra of three-dimensional hyper-crosslinked polymers obtained by liquid-phase polymerization of C₆₀ are discussed.     

Kinetics and Substrate Selectivity of the Oxidation of Saturated Hydrocarbons by Adamantyl Cations in Sulfuric Acid

It was shown that at 70 °C sulfuric acid ([H₂SO₄] > 85 wt.%) solutions of 1-hydroxyadamantane and the solutions obtained in the reaction of adamantane with concentrated sulfuric acid oxidize saturated hydrocarbons (RH). Data on the kinetics, selectivity, kinetic isotope effect, and the effect of the acidity of the medium on the oxidation rate of RH indicate cleavage of the C—H bond in the substrate at the rate-determining stage and the direct participation of adamantyl carbocations.     

Syntheses and Crystal Structures of Two Cadmium Methanetetrabenzoates Featured by Open Framework and Infinite Layers

Colorless single crystals of Cd₂[μ₈‐MTB] · 3H₂O · DMF ( 1 ) were prepared in DMF/H₂O solution [ 1 : space group C2/c (no. 15) with a = 1821.30(6), b = 2175.08(6), c = 1269.87(4) pm, β = 129.684(1)°]. The connection between the methane‐p‐benzoate tetraanions (MTB^4–) and the Cd²⁺ cations leads to a three‐dimensional framework with channels extending along [1 10] and [110] with openings of 670 pm × 360 pm. The channel‐like voids accommodate water molecules and N,N‐dimethylformamide (DMF) molecules not bound to Cd²⁺. Colorless single crystals of [Cd₄(2,2′‐bipy)₄(μ₇‐MTB)₂] · 7DMF ( 2 ) were prepared in DMF in the presence of 2,2′‐bipyridine [ 2 : space group P1 (no. 2) with a = 1224.84(4), b = 1418.85(5), c = 2033.49(4) pm, α = 85.831(2)°, β = 88.351(2)°, γ = 68.261(1)°]. The coordination of MTB^4– to Cd²⁺ results in infinite layers parallel to (001). The layers, not connected by any hydrogen bonds, contain small openings of about 320 pm × 340 pm.     

Effect of the Spacer Chain Length of Organic Dicarboxylic Acid on the Supramolecular Assembly of Two Ternary Zinc (II) Coordination Polymers Derived from Mixed Ligands

Two new Zn^II coordination polymers (CPs), [Zn₂(SA)₂(L)₂]_n ( 1 ) and [Zn(AA)(L)]_n ( 2 ) [L = 1,6‐bis(benzimidazol‐1‐yl)hexane, H₂SA = succinic acid, H₂AA = adipic acid], were synthesized via hydrothermal method and characterized by elemental analysis, infrared spectroscopy, and single‐crystal X‐ray diffraction. CP 1 possesses a sql network, which is further extended into a 3D supramolecular skeleton by non‐classical C–H ··· O hydrogen bonding interactions. CP 2 exhibits a 1D linear chain, which is further assembled into a 2D supramolecular layer by π ··· π stacking interactions. The solid state fluorescence properties of two Zn^II CPs were investigated. Both CPs present high photocatalytic activities for the degradation of methylene blue (MB) under UV light irradiation. The photodegradation efficiency using CP 1 as catalyst is 91.3 % and using CP 2 as catalyst is 85.0 %, respectively.     

Modulation of Foreign Body Reaction against PDMS Implant by Grafting Topographically Different Poly(acrylic acid) Micropatterns

The surface of poly(dimethylsiloxane) (PDMS) is grafted with poly(acrylic acid) (PAA) layers via surface‐initiated photopolymerization to suppress the capsular contracture resulting from a foreign body reaction. Owing to the nature of photo‐induced polymerization, various PAA micropatterns can be fabricated using photolithography. Hole and stripe micropatterns ≈100‐µm wide and 3‐µm thick are grafted onto the PDMS surface without delamination. The incorporation of PAA micropatterns provides not only chemical cues by hydrophilic PAA microdomains but also topographical cues by hole or stripe micropatterns. In vitro studies reveal that a PAA‐grafted PDMS surface has a lower proliferation of both macrophages (Raw 264.7) and fibroblasts (NIH 3T3) regardless of the pattern presence. However, PDMS with PAA micropatterns, especially stripe micropatterns, minimizes the aggregation of fibroblasts and their subsequent differentiation into myofibroblasts. An in vivo study also shows that PDMS samples with stripe micropatterns polarized macrophages into anti‐inflammatory M2 macrophages and most effectively inhibits capsular contracture, which is demonstrated by investigation of inflammation score, transforming‐growth‐factor‐β expression, number of macrophages, and myofibroblasts as well as the collagen density and capsule thickness.     

A New Perspective on Borane Chemistry: The Nucleophilicity of the B−H Bonding Pair Electrons

A number of recently discovered nucleophilic boron compounds, such as boryl anions and borylenes, are breaking the rules regarding boron and boron‐containing compounds and their reputation as Lewis acids/electrophiles. In a similar fashion, the B?H bonding pair electrons in boranes also show nucleophilicity which is ascribed to the lower electronegativity of boron relative to that of hydrogen. However, this nucleophilicity of the B?H bond has received far less attention. Explorations of the nucleophilicity of the B?H bonding pair electrons have led to the formation of B?H?B bonded units and B?H???H?Y dihydrogen bonds, based on which new chemistry has been uncovered, including the elucidation of the mechanism of formation of aminodiborane (ADB), the diammoniate of diborane (DADB), and lithium or sodium salts of octahydrotriborates (B₃H₈^?), as well as the development of more convenient and straightforward synthetic routes to these reagents. Moreover, the recognition of the nucleophilic properties of the B?H bonding pair electrons will also help to more deeply understand the different mechanisms operating in hydroboration reactions.     

Continuous separation of maslinic and oleanolic acids from olive pulp by high‐speed countercurrent chromatography with elution‐extrusion mode

In this work, a continuous high‐speed countercurrent chromatography method has been developed on the basis of elution‐extrusion mode and this method was successfully applied to the separation of maslinic and oleanolic acid from the extract of olive pulp. In the process of ‘elution’, the sample solution was continuously loaded into the column and the maslinic acid was steadily eluted out in this step while highly retained oleanlic acid always stayed in the column. In the process of ‘extrusion’, the oleanlic acid was pushed out of the column with the stationary phase. In this way, we achieved a large sample loading. A total of 120 mL sample solution (about 89.55% of the column volume) which contains 600 mg olive pulp extract was pumped in the apparatus by a constant‐flow pump and the maslinic and oleanolic acids were largely separated within 120 min. Both of these two compounds presented high yields and high purities (271.6 mg for maslinic acid with 86.7% and 83.9 mg oleanolic acids with 83.4%).     

Preparation of eicosapentaenoic acid ethyl ester from fish oil ethyl esters by continuous batch chromatography

Fish oils are rich in eicosapentaenoic acid, which has the wide‐ranging biological activities. The rapid and efficient separation of eicosapentaenoic acid ethyl ester from fish oils ethyl ester is still regarded as a challenge. In this study, we described an effective and flexible chromatography for eicosapentaenoic acid ethyl ester preparation, named continuous batch chromatography, which combined the batch chromatography with the continuous chromatographic operation mode. After continuous batch chromatography experiment, the recovery of eicosapentaenoic acid ethyl ester was 82.01%, the average relative purity and the relative highest purity of eicosapentaenoic acid ethyl ester were 97.82 and 98.98%. The productivity of continuous batch chromatography was 5.48 times higher than that of batch chromatography, while the solvent consumption of eicosapentaenoic acid ethyl ester was 78% of the batch chromatography. This study provided a reference for the separation of the targeted chemical component from multi‐component mixtures.