2-氧代-2-[(2-氯-5-吡啶甲氨基)(芳基)甲基]-4-芳基-5,5-二甲基-1,3,2-二氧膦杂环己烷的合成及其生物活性研究

通过类Mannich 反应“一锅法”合成了10个未见文献报道的含吡啶基的环状α-氨基膦酸酯, 其结构经¹H NMR, ³¹P NMR, IR, MS和元素分析确证. 测定了该系列化合物的杀虫、杀菌和除草活性, 结果表明, 所测化合物的杀虫活性不太好, 但所有化合物在药液浓度为1.0×10^－4 g/mL 时都具有较好的除草活性, 部分化合物在5.0×10^－5 g/mL时显示出良好的杀菌活性.     

Microwave-promoted one-pot synthesis of 4H-thiopyrans from α,β-unsaturated ketones via a three-component reaction

An efficient one-pot synthesis of substituted 4H-thiopyrans has been accomplished from a three-component reaction of α,β-unsaturated ketones, Lawesson’s reagent and alkynes under microwave irradiation.     

1→2 Migration and concurrent glycosidation of phenyl 1-thio-α-mannopyranosides via 2,3-O-cyclic dioxonium intermediates

Treatment of phenyl 2,3-O-cyclic ketene acetal- and 2,3-O-thionocarbonyl-1-thio-mannopyranosides with TMSOTf and MeOTf, respectively, gave the corresponding 2,3-O-cyclic dioxonium intermediates, which proceeded via 1→2 migration and concurrent glycosidation in the presence of alcohols to provide the corresponding 2-S-phenyl glycosides stereoselectively. While the former donors were too labile, the latter donors have proved superior for the present purpose. The X-ray crystallographic structures of phenyl 4-O-methyl-2,3-O-thiocarbonyl-1-thio-α-l-rhamnopyranoside (1), a typical donor for the present reaction, and its anomeric azide analogue (6), which could not undergo the present reaction under similar conditions, are provided.     

Diels-Alder reaction of optically active (E)-γ-keto-α,β-unsaturated p-tolylsulfoxides with cyclopentadiene

The Diels-Alder reaction of enantiomerically pure (E)-γ-keto-α,β-unsaturated p-tolylsulphoxides 3 with cyclopentadiene give four easily separable diastereomers. The effect of several Lewis acids on the reaction was studied, finding a high endo selectivity with respect to the carbonyl group and moderate π-diastereoselectivity using BF₃·Et₂O as catalyst. The reactivity of compounds 3 as well as their endo selectivity are both higher than those observed for the corresponding (E)-3-sulfinylacrylates.     

Chemoselective mono halogenation of β-keto-sulfones using potassium halide and hydrogen peroxide; synthesis of halomethyl sulfones and dihalomethyl sulfones

The synthesis of α-halo β-keto-sulfones using potassium halide and hydrogen peroxide as a chemoselective mono halogenation reagent and the synthesis of α,α-symmetrical and asymmetrical dihalo β-keto-sulfones and α-halo, α-alkyl and β-keto-sulfones is described. Base induced cleavage of α-halo β-keto-sulfones, α,α-dihalo β-keto-sulfones, and α-halo, α-alkyl β-keto-sulfones afforded the corresponding halomethyl sulfones, dihalomethyl sulfones and haloalkyl sulfones.     

One-dimensional α-MnO2: Trapping chemistry of tunnel structures, structural stability, and magnetic transitions

Highly crystalline one-dimensional (1D) α-MnO₂ nanostructures were synthesized by a hydrothermal method. All samples were characterized by X-ray diffraction, transmission electron microscope, thermogravimetric and differential scanning calorimeter, and infrared spectroscopy. During the formation reactions, the tunnel structure of 1D α-MnO₂ was simultaneously modified by NH₄⁺ species and water molecules. The amount of NH₄⁺ species that were trapped in the tunnels is almost independent on the reaction temperature, while the total water content increased with the reaction temperature. The average diameter of α-MnO₂ nanorods increased from 9.2 to 16.5 nm when the reaction temperature increased from 140 to 220 °C. 1D α-MnO₂ was destabilized by a subsequent high-temperature treatment in air, which is accompanied by a structural transformation to 1D Mn₂O₃ of a cubic structure. At low temperatures, all 1D α-MnO₂ nanorods showed two magnetic transitions that were characterized by a decreased Néel temperature with rod diameter reduction. According to the effective magnetic moments experimentally measured, Mn ions presented in the nanorods were determined to be in a mixed valency of high spin state Mn⁴⁺/Mn³⁺.     

哒嗪酮类α1-肾上腺素受体拮抗剂的合成和生物活性研究

将苯(氧)乙胺和苯氧烷胺类α₁-肾上腺素受体拮抗剂中的苯(氧)乙胺、苯氧烷胺片段引入哒嗪酮类化合物中, 设计、合成了30个新的含哒嗪酮环的α₁-肾上腺素受体拮抗剂. 所有新化合物的结构均经¹H NMR, IR, HRMS确证. 生物活性测试表明28个目标物对α₁-肾上腺素受体有较好的拮抗作用(pA₂＞6.00), 化合物6o, 6p, 6q, 6v, 6x, 6y, 10c, 10d的pA₂值＞7.00.     

Fractionation and purification of antioxidant peptides from Chinese sturgeon (Acipenser sinensis) protein hydrolysates prepared using papain and alcalase 2.4L

Protein hydrolysates have the potential to be natural and safer sources of bioactive peptides. In this study, two proteases were used to hydrolyze Chinese sturgeon (Acipenser sinensis) protein, and the hydrolysates were then purified to yield antioxidant peptides. The degree of hydrolysis of 23.56 % and 18.14 % was obtained using papain and alcalase 2.4L, respectivly, and hydrolysates had 96.80 % and 87.24 % total amino acid content, respectivly. The papain hydrolysate (PH) and alcalase 2.4L hydrolysate (AH) showed good antioxidant activity against DPPH^? (IC₅₀ of 3.64 and 3.15 mg/mL) and ABTS^?+ (IC₅₀ of 1.92 and 1.58 mg/mL), respectively. The low-molecular-weight (<1000 Da) fraction of both hydrolysates demonstrated the highest antiradical activity (IC₅₀ of 2.59 and 2.31 mg/mL, DPPH) and (IC₅₀ of 1.54 and 1.36 mg/mL, ABTS), respectively. Nine peptides were separated from both hydrolysates using reverse phase high performance liquid chromatography (RP-HPLC). The IC₅₀ for ABTS^?+ scavenging activity of peptide P5 with valine, glycine and asparagine (MW of 282.13 Da) from PH, and peptide P3 with histidine, glycine and alanine (MW of 302.74 Da) from AH was 0.89 and 0.72 mg/mL, respectively. The fractions and purified peptides obtained from Chinese sturgeon hydrolysates could be utilized as natural antioxidant substitutes in pharmaceuticals and food products.