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...

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.

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.

Asymmetric Bioreduction of 3,5-Bis（trifluoromethyl） Acetophenone to Its Corresponding Alcohol by Candida troplcalis

(S)-3,5-bistrifluoromethylphenyl ethanol is a key chiral intermediate for the synthesis of NK-1 receptor antagonists. Enantioselective synthesis of (S)-3,5-bistrifluoromethylphenyl ethanol was successfully performed in high enantiomeric excess (e.e.) through asymmetric reduction of 3,5-bis(trifluoromethyl) acetophenone catalyzed by Candida tropicalis 104 cells. The influence of some key reaction parameters such as substrate concentration, co-substrate and its concentration, biomass and reaction time was examined, respectively. The results showed that these factors obviously influence the yield, but the optical purity of the prepared product remains intact. The opti-mum conditions for the preparation of (S)-3,5-bistrifluoromethylphenyl ethanol were found to be as follows: sub-strate concentration 50 mmol?L?1; 50 g·L-1 of maltose as co-substrate; wet cell concentration 300 g·L-1; reaction for 30 h. Under above optimal conditions, the maximum yield for (S)-3,5-bistrifluoromethylphenyl ethanol reached 70.3% with 100% of product e.e.

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.

>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.

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),

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.

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.

Molecular and Crystal Structure of Cinnam ylidene Acetophenone

The title compound C 17 H 14 O, M r =234.30, is orthorhombic, space group Pbca with unit cell of a=16.410 (2), b=15.451(2), c=10.261(2); Z=8, D c =1.196 g/cm 3; V=2601(1)  3; λ (Mo Kα)=0.71069, μ (Mo Kα ) =0.73 cm -1 , F (000)=992, final R=0.048, R w =0.053 for 1121 observed reflections with I>3.00σ(I ). As the two phenyl planes and the C 4H 4CO group are non coplanar ,the molecular conjugated system was disturbed.

Synthesis and Crystal Structure of α-(1,2,4-Triazol-1H-yl)-ρ-chloro Acetophenone, [ClC_6H_4COCH_2(C_2H_2N_3)]

The title compound [ClC6H4COCH2(C2H2N3)] has been prepared and characterized by elemental analysis, IR spectrum and X-ray studies. It crystallizes in the monoclinic system, space group P21/c with Mr = 221.64 (C10H8ClN3O), a = 13.420(3), b = 9.720(2), c = 7.900(2) ? b = 92.00(3)? V = 1029.9(4) 3, Z = 4, Dc = 1.429 g/cm3, F(000) = 456, m = 0.345 mm-1, R = 0.0435 and wR=0.0894. The total reflections were 1949 and the independent ones were 1805 (Rint=0.0340), of which 800 were observed with I > 2s(I). The crystal structure consists of a-(1,2,4-triazol-1H- yl)-r-chloro-acetophenone. The existence of p conjugated systems in the molecule affects partly the bond lengths. The triazole and phenyl rings form the dihedral angle of 77.34. The molecules of the title compound connect to each other through extensive hydrogen bonds to form a two-dimensional structure. Elemental analysis and IR spectra are in good agreement with the structure data.

Ni基催化剂对苯乙酮选择加氢性能的影响

以六水合硝酸镍和九水合硝酸铝为前驱体,采用共沉淀法制备了以氧化铝为载体、Ni为活性组分的催化剂粉末;经过催化剂挤条、干燥、焙烧得到相应的固体催化剂。同时采用固定床反应器对该催化剂性能进行了评价。考察了催化剂焙烧温度、反应液体空速、反应压力、反应温度对苯乙酮选择加氢的影响,并利用XRD、BET、H_(2)-TPR、压汞仪对催化剂进行表征。结果表明,催化剂焙烧温度为400℃、反应温度为70℃、反应液体空速为2.5 h^(-1)、反应压力为5 MPa时,苯乙酮转化率和α-苯乙醇的选择性均高于95%。

苯并噻唑型功能化离子液体催化酮酚缩合反应的研究

以N-(3-磺酸基丙基)苯并噻唑、N-(3-磺酸基丙基)-2-巯基苯并噻唑为阳离子和硫酸氢根、对甲苯磺酸根为阴离子合成了4种功能化离子液体(ILs)。利用IR、1HNMR和MS对ILs进行结构表征;利用Hammett法和Ellman法对功能化离子液体的酸度和有效巯基含量等催化性能指标进行表征。同时,评价了该系列功能化离子液体在苯酚分别与环己酮、苯乙酮缩合反应中的催化效果,其中以阳离子结构中含有—SH、阴离子为对甲苯磺酸根的功能化离子液体对不同的酮底物均表现出良好的催化效果。考察反应温度对ILs催化酮酚缩合反应的影响,探究脂肪酮和芳酮的反应活性差异,结果表明,环己酮反应活性明显高于苯乙酮,且酚酮缩合反应是具有动力学和热力学控制特征的反应。基于实验结果分析了ILs催化酮酚缩合反应的可能机理。

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.

苯乙酮一锅法合成吡唑类化合物

吡唑类化合物广泛存在于医药,农药以及功能材料分子之中,同时也是非常有价值的有机合成中间体。本论文研究了在无过渡金属催化条件下,苯乙酮衍生物与N,N-二甲基甲酰胺二甲缩醛反应合成相应的烯胺酮中间体,烯胺酮中间体与水合肼一锅法反应高效合成吡唑类化合物。该环化反应具有合成步骤少,反应产率高,不使用昂贵过渡金属和配体等优点。所合成的吡唑产物经过气相色谱-质谱和核磁共振等进行数据表征和结构鉴定。