- A mild and efficient carboxylate-directed C-H arylation of aryl carboxylic acids with iodobenzenes in water
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An efficient and environmental friendly Pd-catalyzed carboxylate-directed C-H arylation reaction of aryl carboxylic acids with iodobenzenes has been developed in water where Tween 20 was added (2% w/w) to form aqueous micelles to increase the solubility of starting materials. In this aqueous protocol, the reactions proceeded at a lower temperature (80 °C) compared with the traditional procedures using organic solvents (100 °C and above) and wide substrate scopes were demonstrated (15 examples, 62-92% yields).
- Xu, Zhongmiao,Yang, Ting,Lin, Xichen,Elliott, John D.,Ren, Feng
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Read Online
- Desulfonylative Electrocarboxylation with Carbon Dioxide
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Electrocarboxylation of organic halides is one of the most investigated electrochemical approaches for converting thermodynamically inert carbon dioxide (CO2) into value-added carboxylic acids. By converting organic halides into their sulfone derivatives, we have developed a highly efficient electrochemical desulfonylative carboxylation protocol. Such a strategy takes advantage of CO2as the abundant C1 building block for the facile preparation of multifunctionalized carboxylic acids, including the nonsteroidal anti-inflammatory drug ibuprofen, under mild reaction conditions.
- Zhong, Jun-Song,Yang, Zi-Xin,Ding, Cheng-Lin,Huang, Ya-Feng,Zhao, Yi,Yan, Hong,Ye, Ke-Yin
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supporting information
p. 16162 - 16170
(2021/09/02)
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- The thiol-based reduction of Bi(V) and Sb(V) anti-leishmanial complexes
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Low molecular weight thiols including trypanothione and glutathione play an important function in the cellular growth, maintenance and reduction of oxidative stress in Leishmania species. In particular, parasite specific trypanothione has been established as a prime target for new anti-leishmania drugs. Previous studies into the interaction of the front-line Sb(V) based anti-leishmanial drug meglumine antimoniate with glutathione, have demonstrated that a reduction pathway may be responsible for its effective and selective nature. The new suite of organometallic complexes, of general formula [MAr3(O2CR)2] (M = Sb or Bi) have been shown to have potential as new selective drug candidates. However, their behaviour towards the critical thiols glutathione and trypanothione is still largely unknown. Using NMR spectroscopy and mass spectrometry we have examined the interaction of the analogous Sb(V) and Bi(V) organometallic complexes, [SbPh3(O2CCH2(C6H4CH3))2] S1 and [BiPh3(O2CCH2(C6H4CH3))2] B1, with the trifluoroacetate (TFA) salt of trypanothione and L-glutathione. In the presence of trypanothione or glutathione at the clinically relevant pH of 4–5 for Leishmania amastigotes, both complexes undergo facile and rapid reduction, with no discernible difference. However, at a higher pH (6–7), the complexes behave quite differently towards glutathione. The Bi(V) complex is again reduced rapidly but the Sb(V) complex undergoes slow reduction over 8 h (t1/2 = 54 min.) These results give the first insights into why the highly oxidising Bi(V) complexes display low selectivity in their cytotoxicity towards leishmanial and mammalian cells, while the Sb(V) complexes show good selectivity.
- Duffin, Rebekah N.,Stephens, Liam J.,Blair, Victoria L.,Kedzierski, Lukasz,Andrews, Philip C.
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- Visible-Light-Enabled Carboxylation of Benzyl Alcohol Derivatives with CO2 Using a Palladium/Iridium Dual Catalyst
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A highly efficient carboxylation of benzyl alcohol derivatives with CO2 using a palladium/iridium dual catalyst under visible-light irradiation was developed. A wide range of benzyl alcohol derivatives could be employed to provide benzylic carboxylic acids in moderate to high yields. Mechanistic studies indicated that the oxidative addition of benzyl alcohol derivatives was possibly the rate-determining-step. It was also found that a switchable site-selective carboxylation between benzylic C?O and aryl C?Cl moieties could be achieved simply by changing the palladium catalyst.
- Iwasawa, Nobuharu,Jin, Yushu,Toriumi, Naoyuki
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- Aerobic epoxidation of styrene over Zr-based metal-organic framework encapsulated transition metal substituted phosphomolybdic acid
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Catalytic epoxidation of styrene with molecular oxygen is regarded as an eco-friendly alternative to producing industrially important chemical of styrene oxide (STO). Recent efforts have been focused on developing highly active and stable heterogeneous catalysts with high STO selectivity for the aerobic epoxidation of styrene. Herein, a series of transition metal monosubstituted heteropolyacid compounds (TM-HPAs), such as Fe, Co, Ni or Cu-monosubstituted HPA, were encapsulated in UiO-66 frameworks (denoted as TM-HPA@UiO-66) by direct solvothermal method, and their catalytic properties were investigated for the aerobic epoxidation of styrene with aldehydes as co-reductants. Among them, Co-HPA@UiO-66 showed relatively high catalytic activity, stability and epoxidation selectivity at very mild conditions (313 K, ambient pressure), that can achieve 82 % selectivity to STO under a styrene conversion of 96 % with air as oxidant and pivalaldehyde (PIA) as co-reductant. In addition, the hybrid composite catalyst can also efficiently catalyze the aerobic epoxidation of a variety of styrene derivatives. The monosubstituted Co atoms in Co-HPA@UiO-66 are the main active sites for the aerobic epoxidation of styrene with O2/PIA, which can efficiently converting styrene to the corresponding epoxide through the activation of the in-situ generated acylperoxy radical intermediate.
- Hu, Dianwen,Song, Xiaojing,Zhang, Hao,Chang, Xinyu,Zhao, Chen,Jia, Mingjun
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- Relative activity of metal cathodes towards electroorganic coupling of CO2 with benzylic halides
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Electrochemical reduction of benzylic halides represents a convenient route to generating carbanions for their subsequent coupling with CO2 to obtain various carboxylic acids. Despite the industrial prospects of this synthetic process, it still lacks systematic studies of the efficient catalysts and reaction media design. In this work, we performed a detailed analysis of the catalytic activity of a series of different metal electrodes towards electroreduction of benzylic halides to corresponding radicals and carbanions using cyclic voltammetry. Specifically, we screened and summarized the performance of 12 bulk metal cathodes (Ag, Au, Cu, Pd, Pt, Ni, Ti, Zn, Fe, Al, Sn, and Pb) and 3 carbon-based materials (glassy carbon, carbon cloth, and carbon paper) towards electrocarboxylation of eight different benzylic halides and compare it to direct CO2 reduction in acetonitrile. Extensive experimental studies along with a detailed analysis of the results allowed us to map specific electrochemical properties of different metal electrodes, i.e., the potential zones related to the one- and two-electron reduction of organic halides as well as the potential windows where the electrochemical activation of CO2 does not occur. The reported systematic analysis should facilitate the development of nanostructured electrodes based on group 10 and 11 transition metals to further optimize the efficiency of electrocarboxylation of halides bearing specific substituents and make this technology competitive to current synthetic methods for the synthesis of carboxylic acids.
- Engelhardt, Helen,Klinkova, Anna,Medvedev, Jury J.,Medvedeva, Xenia V.
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- Pd(OH)2/C, a Practical and Efficient Catalyst for the Carboxylation of Benzylic Bromides with Carbon Monoxide
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A simple, efficient, cheap, and broadly applicable system for the carboxylation of benzylic bromides with carbon monoxide and water is reported. Upon simple reaction with only 2.5 wt % of Pearlman's catalyst and 10 mol % of tetrabutylammonium bromide in tetrahydrofuran at 110 °C for 4 h, a range of benzylic bromides can be smoothly converted to the corresponding arylacetic acids in good to excellent yields after simple extraction and acid-base wash. The reaction was found to be broadly applicable, scalable, and could be successfully extended to the use of ex situ-generated carbon monoxide and applied to the synthesis of the nonsteroidal anti-inflammatory drug diclofenac.
- Wakuluk-Machado, Anne-Marie,Dewez, Damien F.,Baguia, Hajar,Imbratta, Miguel,Echeverria, Pierre-Georges,Evano, Gwilherm
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p. 713 - 723
(2020/02/04)
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- Oxidation of Alkynyl Boronates to Carboxylic Acids, Esters, and Amides
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A general efficient protocol was developed for the synthesis of carboxylic acids, esters, and amides through oxidation of alkynyl boronates, generated directly from terminal alkynes. This protocol represents the first example of C(sp)?B bond oxidation. This approach displays a broad substrate scope, including aryl and alkyl alkynes, and exhibits excellent functional group tolerance. Water, primary and secondary alcohols, and amines are suitable nucleophiles for this transformation. Notably, amino acids and peptides can be used as nucleophiles, providing an efficient method for the synthesis and modification of peptides. The practicability of this methodology was further highlighted by the preparation of pharmaceutical molecules.
- Li, Chenchen,Li, Ruoling,Zhang, Bing,Zhao, Pei,Zhao, Wanxiang
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supporting information
p. 10913 - 10917
(2020/05/25)
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- Exploration of New Biomass-Derived Solvents: Application to Carboxylation Reactions
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A range of hitherto unexplored biomass-derived chemicals have been evaluated as new sustainable solvents for a large variety of CO2-based carboxylation reactions. Known biomass-derived solvents (biosolvents) are also included in the study and the results are compared with commonly used solvents for the reactions. Biosolvents can be efficiently applied in a variety of carboxylation reactions, such as Cu-catalyzed carboxylation of organoboranes and organoboronates, metal-catalyzed hydrocarboxylation, borocarboxylation, and other related reactions. For many of these reactions, the use of biosolvents provides comparable or better yields than the commonly used solvents. The best biosolvents identified are the so far unexplored candidates isosorbide dimethyl ether, acetaldehyde diethyl acetal, rose oxide, and eucalyptol, alongside the known biosolvent 2-methyltetrahydrofuran. This strategy was used for the synthesis of the commercial drugs Fenoprofen and Flurbiprofen.
- Gevorgyan, Ashot,Hopmann, Kathrin H.,Bayer, Annette
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p. 2080 - 2088
(2020/02/20)
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- BF3·OEt2-promoted tandem Meinwald rearrangement and nucleophilic substitution of oxiranecarbonitriles
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Tandem Meinwald rearrangement and nucleophilic substitution of oxiranenitriles was realized. Arylacetic acid derivatives were readily synthesized from 3-aryloxirane-2-carbonitriles with amines, alcohols, or water in the presence of boron trifluoride under microwave irradiation, and the designed synthetic strategy includes introducing a cyano leaving group into arylepoxides and capturing the in situ generated toxic cyanide with boron trifluoride, making the reaction efficient, safe, and environmentally benign. The reaction occurs through an acid-promoted Meinwald rearrangement, producing arylacetyl cyanides, followed by an addition-elimination process with nitrogen or oxygen-containing nucleophilic amines, alcohols or water. The current method provides a new application of the tandem Meinwald rearrangement.
- Xu, Chuangchuang,Xu, Jiaxi
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p. 127 - 134
(2019/12/26)
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- Synthesis and biological evaluation of 3-arylcoumarin derivatives as potential anti-diabetic agents
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A variety of substituted 3-arylcoumarin derivatives were synthesised through microwave radiation heating. The method has characteristics of environmental friendliness, economy, simple separation, and purification process, less by-products and high reaction yield. Those 3-arylcoumarin derivatives were screened for antioxidant, α-glucosidase inhibitory and advanced glycation end-products (AGEs) formation inhibitory. Most compounds exhibited significant antioxidant and AGEs formation inhibitory activities. Anti-diabetic activity studies showed that compounds 11 and 17 were equipotent to the standard drug glibenclamide in vivo. According to the experimental results, the target compound 35 can be used as a lead compound for the development of new anti-diabetic drugs. The whole experiment showed that anti-diabetic activity is prevalent in 3-arylcoumarins, which added a new natural skeleton to the development of anti-diabetic active drugs.
- Hu, Yuheng,Wang, Bing,Yang, Jie,Liu, Teng,Sun, Jie,Wang, Xiaojing
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- Synthesis and biological evaluation of 3-arylcoumarins as potential anti-Alzheimer's disease agents
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Alzheimer's disease, a neurodegenerative illness, has the extremely complex pathogenesis. Accumulating evidence indicates there is a close relationship between several enzymes and Alzheimer's disease. Various substituted 3-arylcoumarin derivatives were synthesised, and their in vitro activity, including cholinesterase inhibitory activity, monoamine oxidase inhibitory activity, and antioxidant activity were investigated. Most of the compounds exhibited high activity; therefore 3-arylcoumarin compounds have the potential as drug candidates for the treatment of Alzheimer's disease.
- Yang, Jie,Zhang, Pingping,Hu, Yuheng,Liu, Teng,Sun, Jie,Wang, Xiaojing
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p. 651 - 656
(2019/02/19)
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- Preparation method of phenylacetic acid type compound
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The invention discloses a preparation method of a phenylacetic acid type compound. The preparation method of the phenylacetic acid type compound I comprises the following steps that in a solvent and aCO gas phase system, a benzyl halide type compound II, pyridine-2-cobalt carboxylate, palladium acetate and alkaline neutralizers take carbonylation reaction to obtain the phenylacetic acid type compound I. A mixed catalytic system has a synergistic effect; the whole use quantity of catalysts is greatly reduced. When the mixed catalyst is used, a better catalytic effect can be achieved; the characteristics of easily obtaining the catalyst, avoiding the production safety risk of toxic three wastes and the like, reducing the reaction pressure, realizing mild reaction conditions, reducing the production risk, facilitating the production and the like are realized. The formulas are shown in description.
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Paragraph 0104; 0105; 0106
(2019/02/21)
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- An improved method for the synthesis of phenylacetic acid derivatives via carbonylation
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2,4-Dichlorophenylacetic acid is synthesized in high yield via the carbonylation of 2,4-dichlorobenzyl chloride, and various experimental conditions are evaluated. Xylene, bistriphenylphosphine palladium dichloride, tetraethylammonium chloride and sodium hydroxide in solution are added to the reaction system and held at 80 °C under a CO atmosphere. 2,4-Dichlorophenylacetic acid is obtained in a maximum yield of 95percent, and a mechanism for 2,4-dichlorobenzyl chloride carbonylation is proposed. The reaction system provides a mild, effective and novel means by which to prepare phenylacetic acid derivatives from their corresponding benzyl chloride derivatives.
- Li, He,Zhang, Yijun,Liu, Dinghua,Liu, Xiaoqin
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p. 548 - 552
(2019/11/13)
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- Carboxylation of benzylic and aliphatic C-H bonds with CO2 induced by light/ketone/nickel
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A photoinduced carboxylation reaction of benzylic and aliphatic C-H bonds with CO2 is developed. Toluene derivatives capture gaseous CO2 at the benzylic position to produce phenylacetic acid derivatives when irradiated with UV light in the presence of an aromatic ketone, a nickel complex, and potassium tert-butoxide. Cyclohexane reacts with CO2 to furnish cyclohexanecar-boxylic acid under analogous reaction conditions. The present photoinduced carboxylation reaction provides a direct access from readily available hydrocarbons to the corresponding carboxylic acids with one carbon extension.
- Ishida, Naoki,Masuda, Yusuke,Imamura, Yuuya,Yamazaki, Katsushi,Murakami, Masahiro
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supporting information
p. 19611 - 19615
(2019/12/24)
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- Green synthesis method of aromatic acid
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The invention relates to a synthesis method of organic acid, in particular to a green synthesis method of aromatic acid, and belongs to the field of organic synthesis. According to the green synthesismethod of the aromatic acid, an aromatic cyano compound is used as a substrate, a corresponding aromatic acid ammonium salt is obtained after catalytic hydrolysis under catalysis of an alkali catalyst, the obtained aromatic acid ammonium salt is hydrolyzed to obtain the aromatic acid, at the same time, byproduct ammonia water is produced, and the alkali catalyst can be repeatedly applied for manytimes; and the structural formula of the aromatic cyano compound is as follows (please see the specification for the formula). The green synthesis method has the characteristics of simple operation,high product yield, easy separation and basically no generation of salt containing wastewater, small generation amount of wastewater, environmental friendliness and the like, in addition, the catalystcan further be reused for many times, and after repeated application of the catalyst, the total yield of a product can be close to 100%.
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Paragraph 0043; 0045
(2020/01/03)
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- Electrogenerated Sm(II)-Catalyzed CO2 Activation for Carboxylation of Benzyl Halides
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Sm(II)-catalyzed carboxylation of benzyl halides is reported through the electrochemical reduction of CO2. The transformation proceeds under mild reaction conditions to afford the corresponding phenylacetic acids in good to excellent yields. This user-friendly and operationally simple protocol represents an alternative to traditional strategies, which usually proceeds through the C(sp3)-halide activation pathway.
- Bazzi, Sakna,Schulz, Emmanuelle,Mellah, Mohamed
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supporting information
p. 10033 - 10037
(2019/12/24)
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- Inhibition effect of ethanol in naproxen degradation by catalytic ozonation with NiO
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This work evaluated the inhibition effect of low molecular weight alcohol (ethanol) on naproxen (NAP) degradation by conventional and catalytic ozonation. The reaction system considered the ethanol as complementary organic matter in water. The conventional ozonation and in the presence of nickel oxide (O3-NiO) achieved 98% NAP degradation during the first 15 min of reaction despite the presence of ethanol. However, NAP degradation presented a delaying effect during the first minutes of treatment with this alcohol. The latter phenomenon indicates that ethanol concentration played a meaningful role in ozonation effectiveness in comparison with the presence of NiO catalyst. The presence of NiO did not generate differences in the byproducts in comparison with conventional ozonation. The intermediates were detected using the Electrospray Ionization Mass Spectrometry technique and have only one aromatic ring in their chemical structure. In samples without ethanol, these byproducts appeared only in the first 5 min of reaction. The TOC study demonstrated the increment of 25% in the mineralization degree with the presence of NiO due to the formation of ·OH species.
- Aguilar, Claudia Marissa,Chairez, Isaac,Rodríguez, Julia Liliana,Tiznado, Hugo,Santillán, Ricardo,Arrieta, Daniel,Poznyak, Tatiana
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p. 14822 - 14833
(2019/05/24)
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- Preparation method of acid with different substituent groups
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The invention discloses a preparation method of an acid with different substituent groups. A terminal alkyne is lithiated with n-butyllithium, and then reacts with isopropoxyboronic acid pinacol ester, hydrogen chloride is added to achieve quenching, then the obtained reaction product is oxidized by an oxidizing agent, and the oxidized reaction product is separated and purified to obtain the acid.The method of the invention has the advantages of simplicity in operation, one-pot process preparation, no metal catalysis, nontoxic reagents, greenness, environmental friendliness and high atomic utilization rate, and provides a novel and quick way for preparing the acid with different substituent groups; and the obtained acid is an important fine chemical product, and can be widely used in fields of medicines, pesticides, spices and other industries.
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Paragraph 0043-0047
(2019/10/23)
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- A phenylacetic acid compound preparation method (by machine translation)
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The invention relates to the field of chemical synthesis, in particular relates to a preparation method of the compound of phenylacetic acid. The present invention provides a preparation method of the compound of phenylacetic acid, the acid compounds of the structural formula states the benzene second grade shown in formula I, the preparation method comprises the following steps: (1) diazo addition reaction: formula II compound containing vinylidene chloride, acid, diazotization reagent, phase transfer catalyst and a copper catalyst in the system of the formula III compound: (2) hydrolysis reaction: the compound of formula III in the presence of acid hydrolysis of formula I compounds. The present invention provides a preparation method of and is simple, easy operation, low cost of raw materials, mild reaction conditions, low risk, does not need to use expensive noble metal catalyst and complex industrial operation means, the product quality is stable, therefore easy achievement of large-scale industrial production. (by machine translation)
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Paragraph 0128
(2018/03/01)
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- Regio- and Stereoselective Oxidation of Styrene Derivatives to Arylalkanoic Acids via One-Pot Cascade Biotransformations
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Green and selective oxidation methods are highly desired in chemical synthesis and manufacturing. In this work, we have developed a biocatalytic method for the regio- and stereoselective oxidation of styrene derivatives into arylacetic and (S)-2-arylpropionic acids via a one-pot epoxidation–isomerization–oxidation sequence. This was done via the engineering of Escherichia coli (StyABC-EcALDH) coexpressing styrene monooxygenase (SMO), styrene oxide isomerase (SOI) and aldehyde dehydrogenase (EcALDH) as an active and easily available whole-cell catalyst. Regioselective oxidation of styrene and 11 substituted styrenes using the E. coli cells was performed in a one-pot set-up, producing 12 phenylacetic acids in both high conversion and high yield. Engineering of E. coli (StyABC-ADH9v1) coexpressing SMO, SOI and ADH9v1 (a mutated alcohol dehydrogenase) led to biocatalysts capable of regio- and stereoselective oxidation of α-methylstyrene derivatives to the corresponding chiral acids. One-pot asymmetric synthesis of 4 (S)-2-arylpropionic acids was achieved in good conversion and excellent ee with the E. coli cells. This is a new type of asymmetric alkene oxidation to give chiral acids with no chemical counterpart thus far. The cascade bio-oxidation operates under mild conditions, uses molecular oxygen, exhibits very high regio- and enantioselectivity, and gives high conversion, thus providing a green and efficient method for the synthesis of arylacetic acids and (S)-2-arylpropionic acids directly from easily available styrenes. (Figure presented.).
- Wu, Shuke,Zhou, Yi,Seet, Daniel,Li, Zhi
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p. 2132 - 2141
(2017/06/23)
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- Metal-Free Chemoselective Oxidative Dehomologation or Direct Oxidation of Alcohols: Implication for Biomass Conversion
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A transition metal-free, chemoselective reaction was performed using the sodium tert-butoxide-oxygen (NaOtBu-O2) system, resulting in either oxidative dehomologation or direct oxidation of alcohols. In particular, the newly developed protocol may be used to predict the major product formed, which depends on alkyl chain length of the alcohols and reaction conditions. The rational mechanism of this transformation was also demonstrated by performing an 18O isotopic labelling experiment. This protocol presents a straightforward method for biomass conversion of a lignin model compound to phenol and benzoic acid.
- Kim, Sun Min,Shin, Hun Yi,Kim, Dong Wan,Yang, Jung Woon
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p. 241 - 245
(2016/02/27)
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- Metal-free, catalytic regioselective oxidative conversion of vinylarenes: A mild approach to phenylacetic acid derivatives
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A new synthetic approach towards the synthesis of phenylacetic acids from aromatic alkenes has been developed for the first time under mild conditions by employing non-toxic reagents such as molecular iodine and oxone. This metal-free catalytic regioselective oxygenation of vinylarenes proceeds via tandem iodofunctionalization/de-iodination induced rearrangement.
- Kodumuri, Srujana,Peraka, Swamy,Mameda, Naresh,Chevella, Durgaiah,Banothu, Rammurthy,Nama, Narender
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p. 6719 - 6723
(2016/02/03)
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- Palladium-Catalyzed Carboxylation of Benzyl Chlorides with Atmospheric Carbon Dioxide in Combination with Manganese/Magnesium Chloride
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An efficient direct carboxylation of a series of benzyl chlorides with CO2 catalyzed by Pd(OAc)2/dicyclohexyl (2′,6′-dimethoxy-[1,1′-biphenyl]-2-yl)phosphine (SPhos) was developed to afford the corresponding phenylacetic acids in combination with Mn powder as a reducing reagent and MgCl2 as an indispensable additive. The reaction proceeded smoothly under 1 atm CO2. The application of Mn powder instead of a sensitive reducing reagent represents an operationally simple access to phenylacetic acids. Notably, MgCl2 is able to stabilize the (SPhos)2PdII(Bn)(Cl)(η1-CO2)(MgCl2) adduct and thus facilitates CO2 insertion into the PdII-C bond, which is supported by a DFT study. Specific effect: MgCl2 facilitates the direct insertion of CO2 into the PdII-C bond by stabilizing the PdII-CO2 adduct. With MgCl2 as an indispensable additive, the Pd-catalyzed carboxylation of various benzyl chlorides proceeded smoothly under 1 atm CO2, and the application of Mn powder instead of a sensitive reducing reagent makes this protocol an operationally simple access to phenylacetic acids.
- Zhang, Shuai,Chen, Wei-Qiang,Yu, Ao,He, Liang-Nian
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p. 3972 - 3977
(2016/01/26)
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- An efficient one pot method for synthesis of carboxylic acids from nitriles using recyclable ionic liquid [bmim]HSO4 Dedicated to my mentor Professor (Mrs.) Krishna Misra on her 76th birthday
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Environmentally benign ionic liquid [bmim]HSO4 was found suitable for conversion of nitriles into carboxylic acids under mild conditions with excellent purity.
- Kumar, Satyanand,Dixit, Sandeep Kumar,Awasthi, Satish Kumar
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supporting information
p. 3802 - 3804
(2014/07/07)
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- Palladium-catalyzed silver-mediated α-arylation of acetic acid: A new approach for the α-arylation of carbonyl compounds
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A new approach for the α-arylation of acetic acid through Pd-catalyzed silver-mediated direct C-H arylation of acetic acid with aryl iodides was developed. This protocol provided a straightforward method for the synthesis of a diverse set of α-phenylacetic acids. Palladium served on a silver platter: A new approach for the α-arylation of acetic acid through Pd-catalyzed silver-mediated direct C-H arylation of acetic acid with aryl iodides is presented. This protocol provides a straightforward method for the synthesis of a diverse set of α-phenylacetic acids. Deuteration experiments are performed to help elucidate the reaction mechanism.
- Wu, Guo-Jie,Guan, Jing,Han, Fu-She,Zhao, Yu-Long
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p. 1589 - 1593
(2014/06/24)
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- PROCESS FOR SYNTHESIZING PHENYLACETIC ACID BY CARBONYLATION OF TOLUENE
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A production process for substituted phenylacetic acids or ester analogues thereof is disclosed. In this process toluene or toluene substituted with various substituents, an alcohol, an oxidant and carbon monoxide are used as raw materials to obtain compounds comprising structure of phenylacetic acid ester or analogues thereof by catalysis of the complex catalyst formed from transition metal and ligand, and such compounds are hydrolyzed to obtain various substituted phenylacetic acid based compounds. This type of compounds and their derivatives serve as important fine chemicals used widely in the industries of pharmaceuticals, pesticides, perfume and the like.
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Paragraph 0018; 0046; 0047
(2013/11/19)
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- An efficiently cobalt-catalyzed carbonylative approach to phenylacetic acid derivatives
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A highly efficient cobalt-catalyzed carbonylative approach to phenylacetic acid derivatives under one atmosphere pressure is reported. This methodology represents a useful extension of benzimidazole used as ligand in metal catalysis, and the catalytic mechanism has been proved by computer simulation. Notably, this new cobalt precatalyst, which promotes the carbonylation reaction dramatically and has already been used for scale-up experiment of phenylacetic acid derivatives.
- She, Meng-Yao,Xiao, Da-Wei,Yin, Bing,Yang, Zheng,Liu, Ping,Li, Jian-Li,Shi, Zhen
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p. 7264 - 7268
(2013/08/23)
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- Effect of deuterated solvents toward 2,2,2-trichloroethyl esters with a benzylic methylene moiety
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The indium-promoted chemoselective deprotection of 2,2,2-trichloroethyl esters containing a benzylic methylene was successfully achieved by employing deuterated solvents.
- Mineno, Tomoko,Hirayama, Haruyasu,Nakahara, Kazuhide,Yamashita, Mitsuaki,Kansui, Hisao,Moriwaki, Hiroshi
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experimental part
p. 6045 - 6048
(2010/11/21)
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- Exalted resonance demands in the substituent effects on the acetolyses of 2-arylethyl trifluoromethanesulfonates destabilized by cn and cf3 groups
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Substituent effects on the acetolysis rates of 2-aryl-l-cyano-l- (trifluoromethyl)ethyl trifluoromethanesulfonates (α-OTf) and 2-aryl-2-cyano-2-(trifluoromethyl)ethyl trifluoromethanesulfonates (ss-OTf) were investigated by using LArSR equation. The obtained p and r+ values were p = -3.28, r+ = 0.98 and p = -3.48,r+ = 0.93 for the acetolysis of α-OTf and ss-OΥi, respectively. The obtained p values are comparable to those for typical aryl-assisted solvolyses, but the r+ values are much larger. The large r+ values suggest that the ester bond cleavages in the deactivated aryl-assisted solvolyses are assisted by the strong participation of the ss-aryl group.
- Usui, Satoshi,Tsuboya, Shoko,Umezawa, Yukthiro,Hazama, Ken,Okamura, Mutsuo
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experimental part
p. 254 - 260
(2009/05/30)
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- Oxidation of unsaturated compounds in ionic liquids with the use of cyclodextrin-containing catalytic systems
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The Wacker oxidation of alkenes-1 in ionic liquids catalyzed by a system containing palladium, and copper complexes and β-cyclodextrins was studied. It was shown that the use of β-cyclodextrins substantially increases the oxidation rate in biphasic systems olefin/ionic liquid. It was found that the proposed catalytic systems possess substrate selectivity, which is determined by the structure of a receptor molecule.
- Andreeva,Maksimov,Zhuchkova,Predeina,Filippova,Karakhanov
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p. 331 - 336
(2008/09/21)
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- Silver nanocluster redox-couple-promoted nonclassical electron transfer: An efficient electrochemical wolff rearrangement of α-diazoketones
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In this work we report the unique electrocatalytic role of benzoic acid protected silver nanoclusters (Agn, mean core diameter 2.5 nm) in the Wolff rearrangement (Scheme 1) of α-diazoketones. More specifically, the presence of a Agn0/Agn+ redox couple facilitates a nonclassical electron-transfer process, involving chemical reaction(s) interposed between two electron-transfer steps occurring in opposite directions. Consequently, the net electron transfer between the electron mediator (Agn) and α-diazoketone is zero. In-situ UV-visible studies using pyridine as a nucleophilic probe indicate the participation of α-ketocarbene/ketene as important reaction intermediates. Controlled potential coulometry of α-diazoketones using Agn as the anode results in the formation of Wolff rearranged carboxylic acids in excellent yield, without sacrificing the electrocatalyst.
- Sudrik, Surendra G.,Chaki, Nirmalya K.,Chavan, Vilas B.,Chavan, Sambhaji P.,Chavan, Subhash P.,Sonawane, Harikisan R.,Vijayamohanan
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p. 859 - 864
(2007/10/03)
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- A novel method for synthesis of arylacetic acids from aldehydes, N-(2,3,4,6-tetra-O-pivaloylated-D-glucopyranosyl)amine and trimethylsilylcyanide
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A novel synthetic approach for the preparation of arylacetic acids via the reaction of aldehydes, N-(2,3,4,6-tetra-O-pivaloylated-D-glucopyranosyl)amine and trimethylsilylcyanide was developed, in which the N-(2,3,4,6-tetra-O- pivaloylated-D-glucopyranosyl)amine can be recycled conveniently and reused efficiently.
- Zhou, Guo-Bin,Zhang, Peng-Fei,Pan, Yuan-Jiang
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p. 5671 - 5677
(2007/10/03)
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- Kinetics of Ru(III) catalysed oxidation of phenethyl alcohol and para-substituted phenethyl alcohols by Ce(IV) in aqueous nitric acid medium
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A simple, rapid and sensitive spectroscopic method for the kinetics of Ru(III) catalysed oxidation of phenthyl alcohol(PA) by Ce(IV) in aqueous nitric acid medium has been reported under varying conditions. The reaction is followed spectrophotometrically by measuring the decrease in absorbance of Ce(IV) at 350 nm. The rates show first order dependence on [Ce(IV)] and the rate constants evaluated at different [Ce(IV)] are found to be almost the same. Increase in [Ru(III)] has linear relation with the rate of oxidation and order in [Ru(III)] has been found to be fractional. Variation in ionic strength of the medium has significant effect on the rate of reaction. The rates of the reaction have been measured at different temperatures and the activation parameters for all the substrates computed. The rates decrease in the order - OCH3> -CH3 > -H>-Cl>-NO2 of para substituted phenethyl alcohols. Hammett's plot of log kobs versus σ is found to be valid. The correlation between enthalapies and free energies of activation is reasonably linear with an isokinetic temperature of 425K. The rate constant k obeys corresponding equation, k=Q.e-ΔE#RT,e ΔS#/R Ea increases with introduction of electron-withdrawing groups into the benzene ring. The introduction of electron-releasing groups lowers the Ea for the reaction. Similarly, logA decreases with substitution of electron-withdrawing groups and increases with substitution of electron-releasing groups. A plausible mechanism consistent with the experimental results has been proposed.
- Rao, N. Vijaya Bhaskar,Rao, M. Anand
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- An efficient method for one-carbon elongation of aryl aldehydes via their dibromoalkene derivatives
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Various aryl aldehydes were efficiently converted into one-carbon extended aryl acetamides or aryl acetic acids through the reaction of their dibromoalkene derivatives with pyrrolidine in the presence of water under very mild conditions.
- Huh, Dal Ho,Jeong, Ji Sang,Lee, Hee Bong,Ryu, Hoejin,Kim, Young Gyu
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p. 9925 - 9932
(2007/10/03)
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- Microwave-assisted rapid hydrolysis and preparation of thioamides by Willgerodt-Kindler reaction
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Aldehydes and aryl alkyl ketones were efficiently transformed to thioamides with the same number of carbon atoms via Willgerodt-Kindler reaction under microwave irradiation in solvent-free conditions. The thioamides obtained were hydrolyzed to corresponding carboxylic acids with microwave dielectric heating in one minute. Both reactions are very fast and the yields are excellent.
- Matloubi Moghaddam,Ghaffarzadeh
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p. 317 - 321
(2007/10/03)
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- Induced thermolysis of tert-butyl phenylperacetates by thiophenol: Simultaneous occurrence of homolysis and single electron transfer
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Thermolysis of tert-butyl phenylperacetates in the presence of thiophenol takes place via dual mechanism. The two-bond homolysis indicates ρH+ = -1.16, testifying to polar transition states. The single electron transfer yields a radical anion intermediate which undergoes fragmentation with ρET = 1.01.
- Sung Soo Kim,Tuchkin,Chun Soo Kim
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p. 7738 - 7740
(2007/10/03)
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- Study of interactive free-energy relationships on ruthenium(III) catalyzed oxidation of phenyl styryl ketone and its substituted analogues by V(V) in acid medium
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Kinetics of Ru(III) catalyzed oxidation of phenyl styryl ketone (PSK) and its substituted analogues by V(V) has been investigated in aqueous acetic acid-sulphuric acid medium in the temperature range 298-313 K. First-order dependence each on [V(V)], [PSK], and [Ru(III)] was observed. Inverse first-order dependence was observed for [V(IV)]. The rate decreased with the increase in dielectric constant (D) of the medium. The rates were enhanced by electron-donating substituents in both the phenyl rings and decreased by electron-with-drawing substituents. Linear Hammett's plots were obtained for various substituents in benzaldehyde moiety of PSK for a given substituent in acetophenone moiety and vice versa. The mechanism proposed envisages formation of Ru(IV) from V(V)+Ru(III) reaction followed by the attack on C double bond O by Ru(IV). Applicability of interactive free-energy relationship has been tested. The cross-interaction constants qx and qy have been determined at different temperatures and possible interpretations discussed.
- Annapoorna,Prasad Rao,Sethuram
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p. 581 - 588
(2007/10/03)
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- Kinetic Study of Carbonylation of α-Bromo-p-xylene with Iron Pentacarbonyl by Phase-Transfer Catalysis
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The reaction kinetics of the carbonylation of α-bromo-p-xylene (BrCH2C6H4CH3, BX) with iron pentacarbonyl (Fe(CO)5) by phase-transfer catalysis was studied in an organic solvent/alkaline solution. The concentration of tetra-n-butylammonium bromide ((n-C4H9)4NBr, TBAB), NaOH, NaBr, aqueous volume and temperature were evaluated to achieve the optimum reaction condition. The reaction behavior was discussed by the apparent reaction-rate constants for BX and bis(p-methylbenzyl) ketone ((p-CH3C6H4CH2)2CO, BMBK), respectively, and the relationship of consumption of BX and Fe(CO)5. The product distributions of BX with Fe(CO)5 on various reactions conditions were measured. The activation energies was obtained at TBAB = 1.24 and 0 mmol as Well.
- Wu, Ho-Shing,Tan, Wen-Han
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p. 604 - 610
(2007/10/03)
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- Direct Carbonylation of Benzyl Alcohol and Its Analogs Catalyzed by Palladium and HI in Aqueous Systems and Mechanistic Studies
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Carbonylation of benzyl alcohol, benzyl formate, dibenzyl ether, and benzyl phenylacetate catalyzed by palladium complexes and promoted by hydrogen iodide gives phenylacetic acid in moderate to excellent yields in aqueous systems. Application of the carbonylation process to other arylmethanol analogs provides convenient means to prepare 2-naphthaleneacetic acid, 3-isochromanone, 1,4-benzenediacetic acid, and o-hydroxybenzeneacetic acid. A mechanism for the catalytic reaction is proposed, which involves (1) formation of benzyl iodide by the reaction of benzyl alcohol with HI in situ, (2) oxidative addition of benzyl iodide to palladium(0) to form a benzylpalladium iodide species. (3) CO insertion into the Pd-benzyl bond to form a (phenylacetyl)palladium iodide species. (4) reductive elimination of phenylacetyl iodide, and (5) its hydrolysis into phenylacetic acid. Evidence supporting the mechanism was obtained by examining the properties of benzyl- and (phenylacetyl)palladium iodide and chloride complexes. Formation of benzyl(carbonyl)palladium species and migratory insertion of the benzyl group to CO was confirmed by means of NMR at low temperature under high pressure.
- Lin, Yong-Shou,Yamamoto, Akio
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p. 723 - 734
(2007/10/03)
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- An in-depth study of the biotransformation of nitriles into amides and/or acids using Rhodococcus rhodochrous AJ270
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A variety of aliphatic, aromatic and heterocyclic nitriles have been readily hydrolysed into the corresponding amides and/or acids under very mild conditions using Rhodococcus sp. AJ270. The nitrile hydratase involved in this novel nitrile-hydrolysing microorganism efficiently hydrates most nitriles tested, irrespective of the electronic and steric effects of the substituents, to form the amides. Conversion of amides into acids catalysed by the associated amidase is rapid and efficient in most cases. Substrates bearing an adjacent substituent (which may be an ortho substituent on an aromatic nitrile, an adjacent heteroatom in a heterocyclic ring or a geminal substituent in an α,β-unsaturated nitrile) undergo slow hydrolysis of the amides allowing efficient amide isolation. The scope, limitations and reaction mechanism of this enzymatic process have been systematically studied. A molecular size of >7 A diameter and the presence of functions capable of metal complexation near to the nitrile inhibit hydrolysis.
- Meth-Cohn, Otto,Wang, Mei-Xiang
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p. 1099 - 1104
(2007/10/03)
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- Efficient synthesis of α-enaminophosphonates in the series of piperidine and morpholine: Examples of synthetic applications
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Various α-piperidino or α-morpholino alkenylphosphonates are conveniently prepared from the related α-hetero-substituted methylphosphonates, through a Peterson olefination process, which can be easily adapted for a direct homologation of aldehydes into carboxylic acids. An efficient synthesis of α-piperidino or α-morpholino alkylphosphonates and phosphonic acids is proposed.
- Dufrechou,Combret,Malhiac,Collignon
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- Palladium-catalyzed carbonylation of benzyl alcohol and its analogs promoted by HI in aqueous systems
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Carbonylation of benzyl alcohol catalyzed by a palladium(0) complex and promoted by hydrogen iodide gives phenylacetic acid in excellent yields in aqueous systems. The catalysis is proposed to proceed through a benzylpalladium species formed by the oxidative addition of benzyl iodide, produced in situ by the interaction of benzyl alcohol with HI, to a Pd(0) species. Application of the carbonylation process to other arylmethanol analogs provided convenient means to prepare 3-isochromanone, 1,4-benzenediacetic acid, 2-hydroxybenzeneacetic acid and 2-naphthaleneacetic acid.
- Lin, Yong-Shou,Yamamoto, Akio
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p. 3747 - 3750
(2007/10/03)
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- Media controlled photo - Favorskii type rearrangement of α-chloro acetophenones: Synthesis of phenylacetic acids
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Photolysis of substituted α-chloro acetophenones has been studied in different solvent systems wherein 1,2-aryl migration is found to be media controlled. Effect of substituents on the migratory aptitude and a direct access to phenylacetic acids, in practical yields, has been described.
- Dhavale, Dilip D.,Mali, Vasant P.,Sudrik, Surendra G.,Sonawane, Harikisan R.
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p. 16789 - 16794
(2007/10/03)
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- Thermodynamic and nuclear magnetic resonance study of the reactions of α- and β-cyclodextrin with acids, aliphatic amines, and cyclic alcohols
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Titration calorimetry was used to determine equilibrium constants and standard molar enthalpy, Gibbs energy, and entropy changes for the reactions of a series of acids, amines, and cyclic alcohols with α- and β-cyclodextrin. The results have been examined in terms of structural features in the ligands such as the number of alkyl groups, the charge number, the presence of a double bond, branching, and the presence of methyl and methoxy groups. The values of thermodynamic quantities, in particular the standard molar Gibbs energy, correlate well with the structural features in the ligands. These structural correlations can be used for the estimation of thermodynamic quantities for related reactions. Enthalpy-entropy compensation is evident when the individual classes of substances studied herein are considered, but does not hold when these various classes of ligands are considered collectively. The NMR results indicate that the mode of accommodation of the acids and amines in the α-cyclodextrin cavity is very similar, but that the 1-methyl groups in 1-methylhexylamine and in 1-methylheptylamine and the N-methyl group in N-methylhexylamine lie outside the α-cyclodextrin cavity. This latter finding is consistent with the calorimetric results. Many of the thermodynamic and NMR results can be qualitatively understood in terms of van der Waals forces and hydrophobic effects.
- Rekharsky, Mikhail V.,Mayhew, Martin P.,Goldberg, Robert N.,Ross, Philip D.,Yamashoji, Yuko,Inoue, Yoshihisa
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- Efficient transformations of aldehydes and ketones into one-carbon homologated carboxylic acids
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Peterson olefination of aldehydes and ketones with trimethylsilyl(methoxy)(benzotriazol-1-yl)methyl anion 6 afforded 1-(benzotriazol-1-yl)-1-methoxyalk-1-enes 7 which were treated without isolation with zinc bromide and hydrochloric acid, to yield the corresponding one-carbon homologated carboxylic acids 4 in good overall yields.
- Katritzky, Alan R.,Toader, Dorin,Xie, Linghong
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p. 1425 - 1427
(2007/10/03)
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- Catalytic carbonylation of benzylic and allylic bromides by a rhodium zwitterionic complex under phase transfer catalysis conditions
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The zwitterionic rhodium complex, (COD)Rh(η6-C6H5BPh3) (1), can catalyze the carbonylation of benzylic and allylic bromides in the presence of 5 N NaOH and CH2Cl2 at atmospheric pressure and 40 deg C, with (C6H13)4N+ HSO4- as the phase transfer catalyst, to give carboxylic esters as the major products. Keywords: Rhodium; Carbonylation; Zwitterionic complex; Phase transfer catalysis
- Amaratunga, Shiyamalie,Alper, Howard
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- A Study of the Ferrous Ion-initiated SRN1 Reactions of Halogenoarenes with tert-Butyl Acetate and N-Acylmorpholine Enolates
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A detailed preparative study is reported of the ferrous ion-initiated SRN1 reactions of a range of halogenoarenes with the sodium enolates of tert-butyl acetate, n-acetylmorpholine and a number of higher N-acylmorpholines.Smooth and rapid substitution occurs in many cases, and good to excellent yields were obtained of arylacetic esters or acids, arylacetamides and arylalkanamides.The broad scope and limitations of the process have been defined, and the possible role of the ferrous ion is discussed.
- Leeuwen, Milko van,McKillop, Alexander
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p. 2433 - 2440
(2007/10/02)
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- Photolysis of the 1-naphthylmethyl ester of substituted phenylacetic acids: intramolecular charge transfer and rates of decarboxylation of arylacyl radicals
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The photolysis of esters 6 and 8 in methanol leads to products resulting from both naphthylmethyl cations and radicals.The product distribution is nearly independent of X for the esters 6 except when X equals methoxy.A mechanism involving initial homolytic cleavage of the carbon-oxygen bond in the excited singlet state of the ester is proposed.Competition between electron transfer in the radical pair to form the ion pair and decarboxylation of the arylacyloxy radical allows calculations of the rates of this decarboxylation process.The ρ values versus ? is close to zero.When X equals methoxy, intramolecular electron transfer occurs with the naphthalene ring serving as the acceptor and the methoxyaromatic as the donor.This exciplex fragments to carbon dioxide and 1-(1-naphthyl)-2-arylethane. Key words: acyloxy radical, decarboxylation, photolysis of benzylic esters.
- Hilborn, James W.,Pincock, James A.
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p. 992 - 999
(2007/10/02)
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- Enzymic synthesis design and enzymic synthesis of aspartame
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An enzymic synthesis of aspartame (H-Asp-Phe-OMe) has been designed and realized based on the structure-activity study of thermolysin and penicillin amidase hydrolysis of its p-substituted phenylacetyl derivatives. These compounds meet the structural and energetic requirements of two enzymic binding sites. The peptide sweetener has been prepared by thermolysin - catalyzed condensation of the p-substituted phenylacetyl-Asp-OH and H-Phe-OMe follwed by penicillin amidase - catalyzed deprotection of the resulted aspartame precursors.
- Stoineva,Galunsky,Lozanov,Ivanov,Petkov
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p. 1115 - 1122
(2007/10/02)
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