Silica Gel Supported Trifluoromethanesulfonic Acid Catalyzed Beckmann Rearrangement of Cyclohexanone Oxime in Liquid Phase

The liquid phase Beckmann rearrangement of cyclohexanone oxime (CHO) using fuming sulfuric acid as a catalyst is a traditional method for preparing ε-caprolactam (CPL). This process has drawbacks, such as environmental pollution, corrosion of equipment, and low added value of by-product ammonium sulfate. This article designed and prepared a green silica gel-supported trifluoromethanesulfonic acid catalyst for the liquid-phase Beckmann rearrangement of CHO to prepare (CPL). The influencing factors of catalyst preparation and the optimal reaction conditions for Beckmann rearrangement were investigated. It was found that the optimal conditions for catalyst preparation were as follows: raw material silica gel:trifluoromethanesulfonic acid = 1:0.2 (mass ratio), room temperature, stirring time of 2.5 hours, and solvent of acetonitrile, silica gel mesh size is 100 - 200. The optimal reaction conditions for Beckmann rearrangement are CHO: catalyst = 1:2 (mass ratio), temperature of 130˚C, solvent of benzonitrile, volume of 30 mL/g CHO, and reaction time of 4 hours. Under the above conditions, the conversion of CHO is 90%, and the selectivity of CPL is 90%.

Synthesis and Antioxidant Activity of(E)ω-Formylcamphene-Based Thiazole Hydrazone Derivatives

(E)ω-formylcamphene was synthesized fromα-pinene,the main component of turpentine,and then reacted with thiosemicarbazide to obtain(E)ω-formylcamphene thiosemicarbazide 3,which was reacted with 14α-bromoace-tophenone compounds to obtain 14(E)ω-formylcamphene thiazole hydrazone compounds 5a–5n;the yields were all above 80%.The structures of the target compounds were characterized by IR,^(1)H-NMR,^(13)C-NMR,and HR-MS analyses.Then,500,250,125,62.5,and 31.25 mg/L drug solutions were prepared.Free radical scavenging experi-ments of 1,1-diphenyl-2-picrylhydrazyl(DPPH)and 2,2-bis(3-ethyl-benzothiazole-6-sulfonic acid)diammonium salt(ABTS)were carried out with Trolox and L-ascorbic acid as the control samples.The scavenging rates of 14 compounds for DPPH and ABTS free radicals were obtained;the IC_(50) values of scavenging free radicals were fitted using SPSS software.The results show that 14(E)ω-formylcamphene-based thiazole hydrazone compounds exhibited good scavenging effects on the two free radicals,especially when the concentration of the drug solution was 125 and 62.5 mg/L;most compounds exceeded the scavenging efficiency of Trolox and L-ascorbic acid.

Milbemycin Oxime半抗原设计及其抗体制备

通过milbemycin oxime A4、A3(MILO)肟羟基与琥珀酸酐反应,合成了半抗原MILO-5-琥珀酰半酯,采用碳化二亚胺法将其与载体蛋白BSA偶联制备人工抗原.以此人工抗原免疫新西兰大白兔获得多克隆抗体,抗体效价达1:12 800;用此抗体建立的间接竞争酶联免疫吸附(CI-ELISA)检测方法,线性范围在16.00～4 394.18 ng/mL,最低检测限(I10)为6.28 ng/mL.

Flotation performance and adsorption mechanism of novel 1-(2-hydroxyphenyl)hex-2-en-1-one oxime flotation collector to malachite

A novel collector 1-(2-hydroxyphenyl)hex-2-en-1-one oxime(HPHO)was synthesized from 2-hydroxy acetophenone and butyraldehyde.Its flotation performance and adsorption mechanism to malachite were investigated by flotation test,zeta potential,Fourier transform infrared(FTIR)and X-ray photoelectron spectroscopy(XPS)analysis techniques.Compared with benzohydroxamic acid(BA),1-(2-hydroxyphenyl)ethan-1-one oxime(HPEO)and sodium isobutyl xanthate(SIBX),HPHO exhibited excellent collecting power to malachite without additional reagents,such as Na2S regulator and methyl isobutyl carbinol(MIBC)frother.Results of zeta potential indicated that HPHO was coated on malachite surfaces through a chemisorption process.FTIR and XPS data gave clear evidence for the formation of Cu−oxime complex on malachite surfaces after HPHO adsorption through the linkage between C=C,—OH,N—OH group and Cu species.

PEG-SO_3H as catalyst for the Beckmann rearrangement and dehydration of oximes

Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.

Synthesis,Crystal Structure and Biological Activities of O-[(Z)-2-Methylbenzyl] 1-Phenyl-2-(1H-1,2,4-triazol-1-yl)ethanone Oxime

The crystal structure of the title compound （C18H18N4O, Mr = 306.36） has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with α = 4.783（0）, b = 13.577（1）, c = 13.830（1） A, α = 63.581（2）, β = 88.326（2）, γ = 86.161（2）°, V= 802.5（1） A3, Z= 2, Dc = 1.268 g/cm^3, F（000） = 324, μ（MoKa） = 0.082 mm^-1, the final R = 0.0497 and wR = 0.1199 for 3094 observed reflections （I 〉 2σ（I））. The dihedral angles between the phenyl （C（1）-C（4）-（6）） and triazole, the phenyl （C（13）-C（15）-C（18）） and triazole, and the two phenyl rings are 7.9（1）, 69.9（1） and 67.8（1）°, respectively. Strong C-H…π interaction joins molecules into a chain along the c axis and contributes to the stability of the structure. Preliminary bioassay results show that the title compound possesses excellent and selective fungicidal activity against Colletotrichum gossypii but displays moderate to weak insecticidal activity against aphides.

A Convenient and Efficient Procedure for Oxime Ethers

Acetophenone oxime and benzaldehyde oxime were converted to oxime ethers in the presence of alkyl halide or methyl sulfate and KOH in aqueous DMSO in 5 to 70 min. The yields of oxime ethers were 70 - 96%.

AmmAmmoximation of Cyclohexanone to Cyclohexanone Oxime Catalyzed by Titanium Silicalite-1 Zeolite in Three-phase System

An innovative green process of producing ε-caprolactam was proposed by integrating ammoximation and Beckmann rearrangement effectively. As a first part of the new process, TS-1 molecular sieve-catalyzed synthesis of cyclohexanone oxime from cyclohexanone, ammonia and hydrogen peroxide was carried out in a batch plant. Cyclohexane was used as the solvent in the three-phase reaction system. The influences of essential process parameters on ammoximation were investigated. Under the reaction conditions as catalyst content of 2.5% (by mass); H 2 O 2 /yclohexanone molar ratio of 1.10; NH 3 /cyclohexanone molar ratio of 2.20; reaction temperature of 343 K; reaction time of 5 h, high conversion of cyclohexanone and selectivity to oxime (both>99%) were obtained. Thus, the three-phase ammoximation process showed equal catalytic activity as TS-1 but much more convenient and simpler for the separation of catalyst in comparison to the industrial two-phase system with t-butanol used as solvent.

Synthesis and Crystal Structure of (E)-2-phenyl-6,7dihydrobenzofuran-4(5H)-one O-cyanomethyl Oxime

A pair of E/Z-isomers of 2-phenyl-6,7-dihydrobenzofuran-4（5H）-one O-cyanomethyl oxime,C16H14N2O2,as potential drugs for treating peptic ulcer and other acid-related diseases have been synthesized and characterized by IR,MS and NMR spectra.Meanwhile,the crystal of IIIa was obtained and determined by X-ray single-crystal diffraction.Crystal data： monoclinic system,space group P21 /c,a = 8.423（8）,b = 19.596（16）,c = 8.770（8）,β = 107.750（12）°,V = 1379（2）3,Z = 4,F（000） = 560,Dc = 1.283 g/cm3,μ = 0.086 mm 1,R = 0.0681 and wR = 0.2029 for 14472 independent reflections（Rint = 0.0782） and 2428 observed ones（I 2σ（I））.

A Mild Oxidant for the Regeneration of Carbonyl Compounds from Oximes in Nonaqueous Condition

Dioxane-NO2 was employed to oxidize oximes to corresponding aldehydes and ketones in high yield in nonaqueous condition at room temperature. Thr reaction proved to be mild and selective.

Comparative Process for the Preparation of 9-Oxime Erythromycin A

The comparative process for preparing 9-oxime erythromycin A (EMAO) is investigated. EMAO was synthesized and compared by the reaction of erythromycin and hydroxylamine hydrochloride with various bases such as sodium acetate, triethylamine, etc. A new synthetic method is established. The oximation is performed under dynamic buffer system; less degradation impurities are formed. The yield of EMAO reaches more than 95%, HPLC analysis shows that the purity of EMAO is more than 90%, and the E/Z isomeric ratio preponderates over 7∶1.

Synthesis of Novel 1-Alkyl-2-chloro(alkoxy)-1H-indole 3-Carbaldehyde Oximes and Oxime-ethers(esters) Derivatives

A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes（5a―5d） and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes（6a―6d） from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with N-alkylation and oximation as the key steps.An improved one-pot method for the synthesis of 1-alkyl-2-alkoxy-1H-indole-3-carbaldehyde oximes（7a―7h） from 1-alkyl-2-chloro-1H-indole-3-carbaldehydes（3a―3d） was described.The Williamson reactions and esterification reactions were performed and the oxime-ethers and oxime-esters were synthesized,respectively.The new synthesized compounds（3a―11d） were characterized by 1H NMR,IR,MS,and elemental analysis.

Syntheses and Crystal Structures of 12-Oxime Dehydroabietic Acid Derivatives

Three novel dehydroabietate oxime derivatives were synthesized from dehydroabietic acid and their crystal structures were determined by X-ray crystallographic techniques. All of these 12-oxime dehydroabietic acid derivatives crystallize in orthorhombic system, space group P212121. In the structures, rings A and B exhibit chair and half-chair configurations, respectively and form trans ring junction with two methyl groups（C（19） and C（20）） in the axis positions. The oxime groups have E conformations. Comparison of conformations reveals subtle differences principally in ring B due to the modification in C（12）. The E-acetaldehyde oxime derivative 2c showed distinct BKα gate-opening activity with an ionic current increase of 164% at 30 μM versus the control current.

The Effective Catalyst (Cobalt Salt/Lewis Acid) for Beckmann Rearrangement of Cycloalkanone Oximes to Lactams under Mild Conditions

The Beckmann rearrangement of cyclohexanone oxime was achieved by the combined use of cobalt salt and Lewis acids co-catalysts (each 10 mol%). Various combinations of cobalt salts and Lewis acids gave lactams in a satisfactory yield under mild conditions. This method makes it possible to reduce undesirable byproducts.

Trinuclear and Dinuclear Manganese Complexes of 2/4-Formylbenzoic Acid Oxime Ligands:Syntheses and Crystal Structures

Two manganese complexes, [Mn3（2-cba）6（phen）2] 1 （2-cba = 2-cyanobenzoic acid, phe11 = 1,10-phenanthroline） and [MnE（4-fbaO）E（phen）4]（PF6）E.EHEO 2 （4-fbao = 4-formylbenzoic acid oxime）, have been synthesized by the reaction of 2-formylbenzoic acid oxime （2-fbao, HELl） or 4-formylbenzoic acid oxime （4-fbao, HELE） with phen and manganese acetate in ethanol or methanol solution. A translation from the oximino （-CHN=OH） of HELl to cyano （-C-N） was found in the formation of complex 1 at room temperature. The complexes were structurally determined by single-crystal X-ray diffraction. The crystal of compound I belongs to monoclinic, space group C2/c, with a = 17.983（6）, b = 23.364（7）, c =14.589（5） A, β = 92.401（5）° V = 6124（3） A^3, Z = 4, C72H40Mn3N10O12, Mr= 1401.96, Dc = 1.521 g/cm^3, F（000） = 2852.0, Rint = 0.0372, T= 293（2） K,μ = 0.686 mm^-1, the final R = 0.0644 and wR = 0.1813 for 5803 observed reflections with I 〉 2δ（I）. The crystal of compound 2 is of monoclinic system, space group P21/n, with a = 13.050（4）, b = 20.577（5）, c = 13.323（4）A,β = 113.578（3）°, V = 3227.2（14）A3, Z = 2, C64H48F12Mn2N10O8P2, Mr = 1484.94, Dc = 1.528 g/cm^3, F（000） = 1508.0, Rint= 0.0295, T= 293（2） K,μ = 0.539 mm^-1, the final R = 0.0629 and wR = 0.1789 for 5298 observed reflections with I 〉 2σ（I）. Compounds 1 and 2 are linear trinuclear and dinuclear manganese complexes respectively, which are both bridged by carboxylate groups of the ligands.

A novel catalytic method for the regeneration of carbonyl compounds from oximes using aluminum nitrate and NaBr as catalyst

A wide variety of aldoximes and ketoximes were regenerated to corresponding carbonyl compounds with Al（NO3）3·9H2O in presence of catalytic amounts of NaBr in CH2Cl2 at room temperature.

Synthesis and Crystal Structure of a New Nickel(II) Complex with Unsymmetric Quadridentate Schiff Base Containing Oxime

The title complex, C18H15N3NiO3, has been prepared and characterized by X-ray diffraction analysis. It crystallizes in the monoclinic system, space group Cc with a = 10.939(2), b = 22.909(5), c = 6.907(1) ?, β = 116.75(3)°, V = 1545.7(5) ?, Z = 4, Mr = 380.04, F(000) = 784, Dc = 1.633 g/cm3 and μ(MoKα) = 1.279 mm–1. The structure was refined to R = 0.0472 and wR = 0.0893 for 2571 observed reflections with I > 2σ(I). The absolute structure Flack parameter X is 0.01(2). In this crystal structure, strong face-to-face π-π stacking interactions between adjacent molecules lead to a one-dimensional chain structure.

Structure-activity relationships of oxime compounds as flotation collectors by DFT calculations

The relationships between the structure of oxime compounds(R^(1)R^(2)C=NOH,R^(1)/R^(2)=alkyl groups) with different substituents and their corresponding flotation performances were studied. The analyses of density functional theory(DFT) calculations illustrated that the introduced phenyl group at the R^(1) position could enhance the acidity,while the heptyl group could effectively increase the hydrophobicity and benefit van der Waals interactions. Meanwhile,the introduced amino group at the R^(2) position could provide cationic sites to interact with negatively charged surfaces of minerals, while the introduced hydroxyl group could provide additional action sites to form stable chelates with metal ions. Based on the structure-activity relationships, structural optimization was carried out to obtain three efficient collectors, which possessed superior flotation separation performances, proving the effectiveness of the structural modification to oxime compounds in this work.

Synthesis, Crystal Structure and Fungicidal Activity of (Z)-3,3-Dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-one O-2-Chlorobenzyl Oxime Nitrate

The title compound has been synthesized by the reaction of 3,3-dimethyl-1-（1H-1,2,4-triazol-1-yl）butan-2-one oxime with 2-chlorobenzyl chloride, and then treated with 65～68% HNO3. Its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 14.5481（8）, b = 9.3351（5）, c = 13.1911（7） , β = 98.9450（10）°, Z = 4, V = 1769.67（17） 3, Mr = 369.81, Dc = 1.388 g/cm3, S = 1.06, μ = 0.247 mm-1, F（000） = 776, the final R = 0.0352 and wR = 0.0960 for 3069 observed reflections （I 2σ（I））. X-ray crystal structure presents the intramolecular N–H…O hydrogen bond. The packing is nearly parallel without π-π stacking interactions between two adjacent phenyl rings and stabilized by Van der Waals force. The preliminary bioassay shows that the title compound possesses fungicidal activity against Gibberella zeae at the dosage of 25 mg/L.