Enantioselective hydrogenation of acetophenone by(1S,2S)-DPEN-Ru(Ⅱ)Cl_2(PPh_3)_2 encapsulated in Al-MCM-41

A chiral ruthenium complex[（1S,2S）-DPEN]-RuCl_2（PPh_3）_2（DPEN = 1,2-diphenylethylenediamine,PPh_3 = triphenylphosphine） was encapsulated in the channel of Al-MCM-41 by electrostatic adsorption and 1,1-dichlorosilacyclobutane modification.The prepared heterogeneous catalyst showed the same catalytic activity and enantioselectivity as the corresponding homogeneous catalyst in the asymmetric hydrogenation of acetophenone,and could be reused at least seven times without significant loss of catalytic activity and enantioselectivity.

Efficient C_(2)-Symmetric Chiral Schiff Bases for Lanthanide-catalyzed Asymmetric Hydrogenation of Acetophenone

An array of C2-symmetric chiral Schiff bases of substituted salicylaldehyde （1R, 2R）-1, 2-cyclohexanediamine and （R）-（＋）-2, 2＇-diamino-1, 1＇-binaphthalene, incorporated with lanthanide complexes, have been applied as catalysts for asymmetric hydrogenation of acetophenone for the first time. Highly enantioselective product with 90% enantiomeric excess （e.e.） was obtained when the catalyst, hybridized by the bulky electron-donating 3, 5-di-tert-butyl substituted Schiff base （2） and SmCl3.4THF, was employed.

Enantioselective reduction of acetophenone analogues using carrot and celeriac enzymes system

The enantioselective reduction of acetophenone analogues catalyzed by carrot and celeriac was performed in moderate conversions and excellent enantiomeric excesses.The steric factors and electronic effects of the substituents at the aromatic ring were found to significantly affect the efficiency of the enantioselective reduction of acetophenone analogues,while they had a little effect on the enantioselectivity of acetophenone analogues reduction.It was also found that the conversions of acetophenone analogu...

Seed-mediated synthesis of dendritic platinum nanostructures with high catalytic activity for aqueous-phase hydrogenation of acetophenone

This work reports a facile and efficient seed-mediated method for the synthesis of dendritic platinum （Pt） nanoparticles （NPs） at low temperatures of 55-60 ℃ in water, using L-ascorbic acid as a reducing agent and sodium citrate as a capping agent. It is found that the dendritic Pt NPs （10-150 nm） are composed of tiny Pt nanocrystals, which nucleate and grow through the introduced smaller Pt seeds with diameters of 3-5 nm. Further investigation shows that the dendritic Pt nanostructures display excellent catalytic performance in an aqueous-phase aromatic ketone hydrogenation reaction, including： （i） acetophenone conversion rate of 〉 90%, with smaller dendritic Pt NPs （10-46 nm） offering a higher conversion efficiency; （ii） high chemoselectivity toward carbonyl group （90.6%-91.5%）, e.g., the selectivity to l-phenylethanol is -90.1% with nearly 100% acetophenone conversion for 10 nm dendritic Pt NPs within 60 rain, under mild reaction conditions （20 ℃, 1.5 bar H2 pressure, and 1.5 tool% catalyst）. The high catalytic activity, selectivity and stability of the dendritic Pt nanostructures under the organic solvent-free conditions make them promising for many potential applications in green catalytic conversion of hydrophilic biomass derived compounds.

Separation and Purification of Acetophenones from Cynanchum bengei Decne Root Bark by Combination of Silica Gel and High-speed Counter-current Chromatography

[Objectives] To develop a method for separation and purification of acetophenones from Cynanchum bengei Decne root bark by combination of silica gel and high-speed counter-current chromatography( HSCCC). [Methods]The crude extract of Cynanchum bengei Decne root bark was separated by silica gel column chromatography,and parts A and B containing acetophenones were obtained. Then,parts A and B were separated by HSCCC with a two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water( 4∶ 6∶ 4. 5∶ 5. 5 and4∶ 6 ∶ 3 ∶ 7, V/V), respectively. [Results] From 260 mg of part A, four compounds with p-dihydroxybenzene 3. 9 mg(Ⅰ),4-hydroxyacetophenone 17. 1 mg( Ⅱ),2,5-di-hydroxyacetophenone 13. 3 mg(Ⅲ) and 2,4-dihydroxyaceto-phenone 21. 0 mg(Ⅳ) were obtained. And from 300 mg of part B,136 mg of Radix Cynanchi Bungei benzophenone(Ⅴ) was obtained. The purity of compounds determined by HPLC was 97. 0%,96. 6%,99. 2%,99. 7%,99. 5%,respectively. [Conclusions] The established method is simple and efficient. It can be used for separation of acetophenones from Cynanchum bengei Decne root bark and has better practical value,which could provide a reference basis for development and utilization of Cynanchum bengei Decne root bark.

A New Catalyst for Hydrogen Transfer Hydrogenation of Acetophenone

A new C-2-symmetric diamine/diphosphine Ruthenium (II) complex, RuCl2P2N2H4, was used as an excellent catalyst to carry out the catalytic hydrogen transfer reduction of acetophenone. The conversion of acetophenone to 2-phenylethanol was up to 99% under the following reaction conditions: substrate:Ru:(CH3)(2)CHOK = 200:1:12; reaction temperature of 65 degrees C; reaction time of 2 h; normal pressure. A hydride transfer mechanism was also discussed.

KINETICS AND MECHANISM OF PHOTOINDUCED POLYMERIZATION BY α,α-DIMETHOXY-α-PHENYL ACETOPHENONE

α,α-dimethoxy-α-Phenyl acetophenone (DMPA) is an efficient and thermally stable photoinitiator. Here its spectral characteristics in the transient state were shown. The transient species were identified as a benzoyl radical and a dimethoxyi benzyl radical that played a primary initiation role in polymerization. The kinetics and mechanism of the bulk polymerization of MMA were investigated. The exponent of DMPA concentration and k_p/k_1^(1/2) value were found to be 0.5 and 0.066 mol(-1/2)l^(1/2)s^(-1/2), respectively. The existence of oxygen led to obtain the polymer with higher molecular weight, which can be attributed to the occurrence of the subsequent polymerization induced by active polymer end group. In the photocrosslinking reaction, the dependence of DMPA content on initial rate has been found. A principal reason is that the sample contained higher percentage of DMPA has higher light-absorbed efficiency. In solid film, higher concentration of DMPA is permitted to be used because there is little excited state self-quenching effect in the rigid medium.

REACTION OF α-(1H-1,2,4-TRIAZOL-1-YL)ACETOPHENONE WITH PHENYL ISOTHIOCYANATE

Reaction of α-(1H-1,2,4-triazol-1-yl)acetophenone with phenyl isothiocyanate in the presence of a base and subse- quent alkylation leads to the ketene S,N-acetal(2),(4),(7), (8);thiazolidone(3),thiazolidine(5)and 1,3-thiazine(6),

>High Selective Hydrogenation of Acetophenone Catalyzed by Alumina Supported Platinum Nanoclusters

A new preparation and reduction method of ?Al2O3 supported and PVP stabilized platinum nanoclusters was studied. The catalyst exhibited very high activity and selectivity for acetophenone hydrogenation in isopropanol-KOH solution at 25~60C and P H2=1~5 MPa.

STUDIES ON THE DEMETHYLATION-ALKYLATION REACTION OF ACETOPHENONES VIA 2-(1,3-DITHIAN-2-YLIDENE)-1-ARYLETHENONES

2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl, phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols(4).Catalyzing by silica gel,the alcohols 4 were converted to the aryl.ketones(5).The entire process represent a demethylation— alkylation reaction of acetophenones.The mechanism of reaction are proposed and the structure requirement for the conversion of the alcohols(4)was discussed.

Identification and functional characterization of female antennae-biased odorant receptor 23 involved in acetophenone detection of the Indian meal moth Plodia interpunctella

The Indian meal moth,Plodia interpunctella(Lepidoptera:Pyralidae),a globally distributed storage pest,relies on odors that are emitted from stored foods to select a suitable substrate for oviposition.However,the molecular mechanism underlying the chemical communication between P.interpunctella and its host remains elusive.In this study,130 chemosensory genes were identified from the transcriptomes of 7 P.interpunctella tissues,and the quantitative expression levels of all 56 P.interpunctella odorant receptor genes(PintORs)were validated using real-time quantitative polymerase chain reaction.The functional characteristics of 5 PintORs with female antennae-biased expression were investigated using 2-electrode voltage clamp recordings in Xenopus laevis oocytes.PintOR23 was found to be specifically tuned to acetophenone.Acetophenone could elicit a significant electrophysiological response and only attracted mated females when compared with males and virgin females.In addition,molecular docking predicted that the hydrogen bonding sites,TRP-335 and ALA-167,might play key roles in the binding of PintOR23 to acetophenone.Our study provides valuable insights into the olfactory mechanism of oviposition substrate detection and localization in P.interpunctella and points toward the possibility of developing eco-friendly odorant agents to control pests of stored products.

Asymmetric Reduction of 3,5-Bistrifluoromethyl Acetophenone with NADH Regeneration by Immobilized Cells of Saccharomyces rhodotorula in Aqueous-Organic Solvent Biphasic System

Asymmetric reduction of 3,5-bistrifluoromethyl acetophenone to produce(S)-3,5-bistrifluoromethylphenyl ethanol was successfully carried out with sodium alginate immobilized Saccharomyces rhodotorula cells in an aqueous-organic solvent biphasic system.The possible influential factors were examined thoroughly according to their effects on conversion rate and e.e of the product.Organic solvents were rated by their biocompatibility and conversion potential.The immobilized cells [125 mg/mL in 20 mmol/L Tris-HCl buffer and 5%(j) octane at pH 8] showed the best conversion with a substrate concentration of 1.42 g/L at 30℃ with glucose as co-substrate for cofactor regeneration.Sequential 8-batch process was carried out with immobilized cells with a slow decrease in conversion and e.e.The immobilized cells showed stable catalytic activity with 50% reserved activity and are superior especially in reusability in comparison with resting cells.

Rapid separation of acetophenone and its monohydroxy isomers by capillary electrophoresis

This work describes the development of a capillary electrophoresis （CE） method for the simultaneous separation of acetophenone （AP）, 2-hydroxyacetophenone （2-HAP）, 3-hydroxyacetophenone （3-HAP） and 4-hydroxyacetophenone （4-HAP） in synthetic mixtures using 10 mmol/L of sodium tetraborate buffer （pH 9.5）. The aim of this work is to demonstrate the effectiveness of CE to separate AP and its monohydroxy isomers and to define how the separations are affected by buffers, buffer pH, sample matrices and separation voltage. This method was successfully used for the trace level separation and determination of 2-HAP, 3-HAP and 4-HAP in synthetic mixture and 4-HAP in spiked plasma samples.

Asymmetric Reduction of Acetophenone O-Methyloxime with Reagents Prepared from L-Proline and Borane

Asymmetric reduction of acetophenone O methyloxime with reagents in situ prepared from L proline and borane has been investigated. A series of conditions optimization were made, including an examination of the effect of the temperature of catalyst pretreatment, the temperature of reduction, the amount of borane, the additive, the solvent, the reducing agent and various chiral auxiliaries on the enantioselectivity. Under the optimal condition, ( S ) α phenylethylamine was obtained in 53% yield with 83 1% ee in the presence of 25 mol% L proline.

Microbial Transformation of Acetophenone to 2-Phenylethanol

Microorganisms are commonly used to transform chemicals to chiral compounds. Pseudomonas cepacia 1813, Pseudomonas stutzeri 1317, Saccharomyces cerevisiae 1912, and 5 Escherichia coli strains were used to transform acetophenone to 2 phenylethanol. The results show that the E. coli strains have the poorest biotransformation ability. P. stutzeri 1317 provides the best transformation ability with a transformation rate of 30% achieved with either whole or broken P. stutzeri 1317 cells for a reaction pH of 8.2 and an initial acetophenone concentration of 2 g/L. An acetophenone concentration of 10 g/L strongly inhibits the biotransformation for a pH of 8.2. Crude alcohol dehydrogenase obtained from S. cerevisiae 1912 transforms acetophenone to 2 phenylethanol when nicotinamide adenine dinucleotide reduced (NADH) is added.

An Unexpected Discovery in the Willgerodt-Kindler Reaction of Acetophenone--the Formation of the 4-（Benzoylthiocarbonyl）morpholine

The Willgerodt-Kindler reaction of acetophenone was studied. Apart from the normal product 4-（benzylthiocarbonyl）morpholine, another product 4-（benzoylthiocarbonyl）morpholine was obtained unexpectedly. The structure of the latter was confirmed by 1R, IH NMR spectra and X-ray diffraction analysis. The mechanism of the reaction was discussed.

Cyclization of 2-methoxy-6-(substituted benzyloxy)acetophenone hydrazones in the presence of polyphosphoric acid(PPA)

Cyclization of 2-methoxy-6-benzyloxy acetophenone hydrazone gave 3-methyl-4-meth- oxy indazole and 3-methyl-4-methoxy-7-benzyl indazole in the presence of polyphosphoric acid (PPA).The hydrazone was probably converted to 2-hydroxy-6-methoxy acetophenone hydra- zone and 2-hydroxy-3-benzyl-6-methoxy acetophenone hydrazone followed by cyclization to the corresponding indazoles in acidic conditions.Cyelization of 2-methoxy-6-(halo or alkyl or aryl benzyloxy)acetophenone hydrazones gave similar products.Cyclization of 2-methoxy-6- (p-nitrobenzyloxy)acetophenone hydrazone gave 2-(p-nitrophenyl)-3-methyl-4-methoxy benzo- furan and 3-methyl-4-methoxy indazole while 2-methoxy-6-(m-nitrobenzyloxy)acetophenone hydrazone gave 3-methyl-4-methoxy indazole,3-methyl-4-methoxy-7-(m-nitrophenyl)indazole and 3-methyl-4-(m-nitrobenzyloxy)indazole.

Efficient oxidation of ethylbenzene catalyzed by cobalt zeolitic imidazolate framework ZIF-67 and NHPI

Efficient catalytic oxidation of ethylbenzene to acetophenone was realized using the catalytic system of cobalt zeolitic imidazolate framework ZIF-67/N-hydroxyphthalimide （NHPI） under mild conditions. 95.2% conversion of ethylbenzene with 90.3% selectivity to acetophenone could be obtained at 373 K under 0.3 MPa 02 for 9 h. The results show that there exists synergetic effect between ZIF-67 and NHPI. 1-Phenylethyl hydroperoxide （PEHP） was generated via a radical process involving the hydrogen abstraction from ethylbenzene by phthalimide N-oxyl, and subsequently effectively decomposed to acetophenone by ZIF-67.