- Mechanism of solvolysis of substituted benzyl chlorides in aqueous ethanol
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The mechanism of solvolyses of activated ortho-, meta- and para-substituted benzyl chlorides in aqueous ethanol has been studied by using the Hammett-Brown and Yukawa-Tsuno treatments as well as by correlating logarithms of solvolysis rate constants with relative stabilities of corresponding benzyl carbocations in water calculated at the IEFPCM-M06–2X/6-311+G(3df,3pd) level of theory. Benzyl chlorides containing strong conjugative electron-donors in the para-position solvolyze by the SN1 mechanism, whereas other activated benzyl chlorides solvolyze by the SN2 mechanism via loose transition states.
- Denegri, Bernard,Mati?, Mirela,Va?ko, Monika
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supporting information
(2021/11/22)
-
- Discovery of Novel Azetidine Amides as Potent Small-Molecule STAT3 Inhibitors
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We optimized our previously reported proline-based STAT3 inhibitors into an exciting new series of (R)-azetidine-2-carboxamide analogues that have sub-micromolar potencies. 5a, 5o, and 8i have STAT3-inhibitory potencies (IC50) of 0.55, 0.38, and 0.34 μM, respectively, compared to potencies greater than 18 μM against STAT1 or STAT5 activity. Further modifications derived analogues, including 7e, 7f, 7g, and 9k, that addressed cell membrane permeability and other physicochemical issues. Isothermal titration calorimetry analysis confirmed high-affinity binding to STAT3, with KD of 880 nM (7g) and 960 nM (9k). 7g and 9k inhibited constitutive STAT3 phosphorylation and DNA-binding activity in human breast cancer, MDA-MB-231 or MDA-MB-468 cells. Furthermore, treatment of breast cancer cells with 7e, 7f, 7g, or 9k inhibited viable cells, with an EC50 of 0.9-1.9 μM, cell growth, and colony survival, and induced apoptosis while having relatively weaker effects on normal breast epithelial, MCF-10A or breast cancer, MCF-7 cells that do not harbor constitutively active STAT3.
- Brotherton-Pleiss, Christine,Yue, Peibin,Zhu, Yinsong,Nakamura, Kayo,Chen, Weiliang,Fu, Wenzhen,Kubota, Casie,Chen, Jasmine,Alonso-Valenteen, Felix,Mikhael, Simoun,Medina-Kauwe, Lali,Tius, Marcus A.,Lopez-Tapia, Francisco,Turkson, James
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p. 695 - 710
(2021/01/14)
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- Fine-tuning of the pharmacological potential of novel thiazolium ionic liquids by anion alteration
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A novel series of thiazolium ionic liquids (TILs) bound to chloride (2a-c), tetrafluoroborate (BF4) (3a-c), and bis-(trifluoromethanesulfonimide) (Tf2N) anions (4a-c) was synthesized and their physicochemical characteristics were investigated using various microanalytical techniques. The pharmacological potential of the new TILs was assessed as chemotherapeutic agents for bacterial infections and ovarian cancer (SKOV-3). Notably, ILs with the same cations become more bactericidal upon their binding with the strongest chaotropic anion (TN2f). The in vitro toxicity of the TILs toward ovarian carcinoma cell lines (SKOV-3) and normal human skin fibroblast cells (HSF) revealed that all tested TILs have the capacity to induce a dose- and time-dependent decline in SKOV-3 cell viability, with Tf2N-linked TILs (4a-c) having a preferable efficacy. In addition, the new compounds showed excellent selectivity for cancer cells (SKOV-3) over healthy cells (HSF). [iPBzTh][Tf2N] (4b) is the most cytotoxic and specific one and may act as a promising anti-ovarian cancer agent.
- Alfaifi, Mohammad Y.,Elbehairi, Serag Eldin I.,Elshaarawy, Reda F. M.,Gad, Emad M.,Shati, Ali A.
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p. 458 - 469
(2022/01/19)
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- Formamide-Catalyzed Nucleophilic Substitutions: Mechanistic Insight and Rationalization of Catalytic Activity
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Herein, detailed mechanistic investigations into formamide-catalyzed nucleophilic substitution (SN) of alcohols are reported. Alkoxyiminium chlorides and hexafluorophosphates were synthesized and characterized as a key intermediate of the catalytic cycle. The determination of reaction orders and control experiments indicated that the nucleophilic attack of the formamide catalyst onto the reagent BzCl is the rate-determining step. Linear free energy relationship revealed a correlation between the quantified Lewis basicity strength of formamides by means of 11B NMR spectroscopy and their catalytic activity in SN-transformations. The observed difference in catalytic ability was attributed to the natural bond order charge, dipole moment, and Sterimol parameter B5. Importantly, this rationalization enables the prediction of the capacity of formamides to promote SN-type transformations in general.
- Hilt, Gerhard,Huy, Peter H.,Kohlmeyer, Corinna,Sch?fer, André
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p. 11567 - 11577
(2020/11/17)
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- Lewis Base Catalysis Enables the Activation of Alcohols by means of Chloroformates as Phosgene Substitutes
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Nucleophilic substitutions (SN) are typically promoted by acid chlorides as sacrificial reagents to improve the thermodynamic driving force and lower kinetic barriers. However, the cheapest acid chloride phosgene (COCl2) is a highly toxic gas. Against this background, phenyl chloroformate (PCF) was discovered as inherently safer phosgene substitute for the SN-type formation of C?Cl and C?Br bonds using alcohols. Thereby, application of the Lewis bases 1-formylpyrroldine (FPyr) and diethylcyclopropenone (DEC) as catalysts turned out to be pivotal to shift the chemoselectivity in favor of halo alkane generation. Primary, secondary and tertiary, benzylic, allylic and aliphatic alcohols are appropriate starting materials. A variety of functional groups are tolerated, which includes even acid labile moieties such as tert-butyl esters and acetals. Since the by-product phenol can be isolated, a recycling to PCF with inexpensive phosgene would be feasible on a technical scale. Eventually, a thorough competitive study demonstrated that PCF is indeed superior to phosgene and other substitutes.
- Zoller, Ben,Stach, Tanja,Huy, Peter H.
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p. 5637 - 5643
(2020/09/21)
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- An efficient and convenient chloromethylation of some aromatic compounds catalyzed by zinc iodide
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Treatment of a series of aromatic hydrocarbons and O-carbethoxy phenol substrates with a mixture of chlorosulfonic acid and dimethoxymethane in CH2Cl2 catalyzed by zinc iodide affords the corresponding chloromethyl derivatives in good to excellent yields.
- Tang, Jian,Liu, Hongtao,Zhou, Jing,Zhang, Xingxian
-
-
- A practical and convenient Blanc-type chloromethylation catalyzed by zinc chloride under solvent-free conditions
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Chloromethylation of various aromatic hydrocarbons and substituted phenolic derivatives with dimethoxymethane and chlorosulfonic acid was carried out in the presence of 10 mol% of ZnCl2 in a mild and efficient manner under solvent-free conditions. In addition, 2,6-dimethyltyrosine was synthesized in high yield via this protocol.
- Tang, Jian,Liu, Hongtao,He, Kailun,Zhang, Xingxian
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p. 925 - 932
(2019/03/17)
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- Organocatalytic Chlorination of Alcohols by P(III)/P(V) Redox Cycling
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A catalytic system for the chlorination of alcohols under Appel conditions was developed. Benzotrichloride is used as a cheap and readily available chlorinating agent in combination with trioctylphosphane as the catalyst and phenylsilane as the terminal reductant. The reaction has several advantages over other variants of the Appel reaction, e.g., no additional solvent is required and the phosphane reagent is used only in catalytic amounts. In total, 27 different primary, secondary, and tertiary alkyl chlorides were synthesized in yields up to 95%. Under optimized conditions, it was also possible to convert epoxides and an oxetane to the dichlorinated products.
- Longwitz, Lars,Jopp, Stefan,Werner, Thomas
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p. 7863 - 7870
(2019/06/27)
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- Nucleophilic Substitutions of Alcohols in High Levels of Catalytic Efficiency
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A practical method for the nucleophilic substitution (SN) of alcohols furnishing alkyl chlorides, bromides, and iodides under stereochemical inversion in high catalytic efficacy is introduced. The fusion of diethylcyclopropenone as a simple Lewis base organocatalyst and benzoyl chloride as a reagent allows notable turnover numbers up to 100. Moreover, the use of plain acetyl chloride as a stoichiometric promotor in an invertive SN-type transformation is demonstrated for the first time. The operationally straightforward protocol exhibits high levels of stereoselectivity and scalability and tolerates a variety of functional groups.
- Stach, Tanja,Dr?ger, Julia,Huy, Peter H.
-
supporting information
p. 2980 - 2983
(2018/05/28)
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- A General Catalytic Method for Highly Cost- and Atom-Efficient Nucleophilic Substitutions
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A general formamide-catalyzed protocol for the efficient transformation of alcohols into alkyl chlorides, which is promoted by substoichiometric amounts (down to 34 mol %) of inexpensive trichlorotriazine (TCT), is introduced. This is the first example of a TCT-mediated dihydroxychlorination of an OH-containing substrate (e.g., alcohols and carboxylic acids) in which all three chlorine atoms of TCT are transferred to the starting material. The consequently enhanced atom economy facilitates a significantly improved waste balance (E-factors down to 4), cost efficiency, and scalability (>50 g). Furthermore, the current procedure is distinguished by high levels of functional-group compatibility and stereoselectivity, as only weakly acidic cyanuric acid is released as exclusive byproduct. Finally, a one-pot protocol for the preparation of amines, azides, ethers, and sulfides enabled the synthesis of the drug rivastigmine with twofold SN2 inversion, which demonstrates the high practical value of the presented method.
- Huy, Peter H.,Filbrich, Isabel
-
supporting information
p. 7410 - 7416
(2018/04/30)
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- Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
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Herein, a method for the nucleophilic substitution (SN) of benzyl alcohols yielding chloro alkanes is introduced that relies on aromatic sulfoxides as Lewis base catalysts (down to 1.5 mol-%) and benzoyl chloride (BzCl) as reagent. A systematic screening of various sulfoxides and other sulfinyl containing Lewis bases afforded (2-methoxyphenyl)methyl sulfoxide as optimal catalyst. In contrast to reported formamide catalysts, sulfoxides also enable the application of plain acetyl chloride (AcCl) as reagent. In addition, it was demonstrated that weakly electrophilic carboxylic acid chlorides like BzCl promote Pummerer rearrangement of sulfoxides already at room temperature. This side-reaction also provided the explanation, why sulfoxide catalyzed SN-reactions of alcohols do not allow the effective production of aliphatic and electron deficient chloro alkanes. Comparison experiments provided further insight into the reaction mechanism.
- Motsch, Sebastian,Schütz, Christian,Huy, Peter H.
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supporting information
p. 4541 - 4547
(2018/09/13)
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- Highly selective halogenation of unactivated C(sp3)-H with NaX under co-catalysis of visible light and Ag@AgX
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The direct selective halogenation of unactivated C(sp3)-H bonds into C-halogen bonds was achieved using a nano Ag/AgCl catalyst at RT under visible light or LED irradiation in the presence of an aqueous solution of NaX/HX as a halide source, in air. The halogenation of hydrocarbons provided mono-halide substituted products with 95% selectivity and yields higher than 90%, with the chlorination of toluene being 81%, far higher than the 40% conversion using dichlorine. Mechanistic studies demonstrated that the reaction is a free radical process using blue light (450-500 nm), with visible light being the most effective light source. Irradiation is proposed to cause AgCl bonding electrons to become excited and electron transfer from chloride ions induces chlorine radical formation which drives the substitution reaction. The reaction provides a potentially valuable method for the direct chlorination of saturated hydrocarbons.
- Liu, Shouxin,Zhang, Qi,Tian, Xia,Fan, Shiming,Huang, Jing,Whiting, Andrew
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p. 4729 - 4737
(2018/10/23)
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- Selective C-H halogenation over hydroxylation by non-heme iron(iv)-oxo
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Non-heme iron based halogenase enzymes promote selective halogenation of the sp3-C-H bond through iron(iv)-oxo-halide active species. During halogenation, competitive hydroxylation can be prevented completely in enzymatic systems. However, synthetic iron(iv)-oxo-halide intermediates often result in a mixture of halogenation and hydroxylation products. In this report, we have developed a new synthetic strategy by employing non-heme iron based complexes for selective sp3-C-H halogenation by overriding hydroxylation. A room temperature stable, iron(iv)-oxo complex, [Fe(2PyN2Q)(O)]2+ was directed for hydrogen atom abstraction (HAA) from aliphatic substrates and the iron(ii)-halide [FeII(2PyN2Q)(X)]+ (X, halogen) was exploited in conjunction to deliver the halogen atom to the ensuing carbon centered radical. Despite iron(iv)-oxo being an effective promoter of hydroxylation of aliphatic substrates, the perfect interplay of HAA and halogen atom transfer in this work leads to the halogenation product selectively by diverting the hydroxylation pathway. Experimental studies outline the mechanistic details of the iron(iv)-oxo mediated halogenation reactions. A kinetic isotope study between PhCH3 and C6D5CD3 showed a value of 13.5 that supports the initial HAA step as the RDS during halogenation. Successful implementation of this new strategy led to the establishment of a functional mimic of non-heme halogenase enzymes with an excellent selectivity for halogenation over hydroxylation. Detailed theoretical studies based on density functional methods reveal how the small difference in the ligand design leads to a large difference in the electronic structure of the [Fe(2PyN2Q)(O)]2+ species. Both experimental and computational studies suggest that the halide rebound process of the cage escaped radical with iron(iii)-halide is energetically favorable compared to iron(iii)-hydroxide and it brings in selective formation of halogenation products over hydroxylation.
- Rana, Sujoy,Biswas, Jyoti Prasad,Sen, Asmita,Clémancey, Martin,Blondin, Geneviève,Latour, Jean-Marc,Rajaraman, Gopalan,Maiti, Debabrata
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p. 7843 - 7858
(2018/10/31)
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- SNAr catalysis enhanced by an aromatic donor-acceptor interaction; Facile access to chlorinated polyfluoroarenes
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Selective catalytic SNAr reaction of polyfluoroaryl C-F bonds with chloride is shown. Stoichiometric TMSCl makes the reaction exergonic and allows catalysis, which involves ground state elevation of chloride, aromatic donor-acceptor interactions, and stabilization of the Meisenheimer complex. Traditional cross-coupling of the products is now possible and demonstrates the utility.
- Senaweera, Sameera,Weaver, Jimmie D.
-
supporting information
p. 7545 - 7548
(2017/07/12)
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- METHOD OF CONVERTING ALCOHOL TO HALIDE
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The present invention relates to a method of converting an alcohol into a corresponding halide. This method comprises reacting the alcohol with an optionally substituted aromatic carboxylic acid halide in presence of an N-substituted formamide to replace a hydroxyl group of the alcohol by a halogen atom. The present invention also relates to a method of converting an alcohol into a corresponding substitution product. The second method comprises: (a) performing the method of the invention of converting an alcohol into the corresponding halide; and (b) reacting the corresponding halide with a nucleophile to convert the halide into the nucleophilic substitution product.
- -
-
Page/Page column 50; 69; 70
(2017/01/02)
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- Formamides as Lewis Base Catalysts in SNReactions—Efficient Transformation of Alcohols into Chlorides, Amines, and Ethers
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A simple formamide catalyst facilitates the efficient transformation of alcohols into alkyl chlorides with benzoyl chloride as the sole reagent. These nucleophilic substitutions proceed through iminium-activated alcohols as intermediates. The novel method, which can be even performed under solvent-free conditions, is distinguished by an excellent functional group tolerance, scalability (>100 g) and waste-balance (E-factor down to 2). Chiral substrates are converted with excellent levels of stereochemical inversion (99 %→≥95 % ee). In a practical one-pot procedure, the primary formed chlorides can be further transformed into amines, azides, ethers, sulfides, and nitriles. The value of the method was demonstrated in straightforward syntheses of the drugs rac-Clopidogrel and S-Fendiline.
- Huy, Peter H.,Motsch, Sebastian,Kappler, Sarah M.
-
supporting information
p. 10145 - 10149
(2016/08/16)
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- Synthesis method of p-tert-butyl benzyl chloride
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The invention discloses a synthesis method of p-tert-butyl benzyl chloride. Compared with the prior art, the synthesis method has the advantages of shorter reaction time, simplicity in operation, reliable process and easiness of controlling a reaction, and small pollution to the environment by raw materials and byproducts; on one hand, the yield of crops is increased under the condition of guaranteeing the purity and the reaction time is shortened so that the production efficiency is improved and the production cost is reduced; on the other hand, the synthesis method can be used for large-batch industrial production and the pollution to the environment by the reaction raw materials and additional products is reduced.
- -
-
Paragraph 0016; 0017; 0018
(2016/10/07)
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- Synthetic method of buclizine drug intermediate 4-tert-butyl-benzyl-chloride
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A synthetic method of buclizine drug intermediate 4-tert-butyl-benzyl-chloride comprises steps as follows: 1.6 mol of tert-butyl benzene, 530 ml of a chloroethane solution, 2.1-2.3 mol of methylamine, 1.6 mol of cuprous chloride and 310 ml of oxalic acid are added to a reaction container provided with a stirrer, a thermometer and a dropping funnel, the stirring speed is controlled within 150-190 rpm, the temperature of the solution is increased to 70-75 DEG C, 210 ml of cyclohexane is added, the solution is stirred continuously to react for 10-13 h, the temperature of the solution is decreased to 40-45 DEG C, an oil layer is separated, washed with a salt solution, a potassium sulfite solution and a dehydrating agent and subjected to reduced pressure distillation, fractions at 90-95 DEG C are collected and recrystallized in toluene, and 4-tert-butyl-benzyl-chloride is obtained.
- -
-
Paragraph 0015; 0016
(2016/10/27)
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- A Visible-Light-Induced α-H Chlorination of Alkylarenes with Inorganic Chloride under NanoAg@AgCl
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An efficient, photocatalytic chlorination of alkylarene α-H groups using NaCl/HCl as a chlorine source has been developed, which involves a radical mechanism under visible-light (including sunlight) conditions. A chlorine radical is proposed to be formed by an electron transfer from chloride ion to O2 in air through the bandgap hole of the semiconductor AgCl. The chlorination protocol is characterized by its use of natural sunlight or other visible light, mild conditions, cheap source of chlorine, green solvent, and high selectivity. The yield of benzylchloride is 95 % with a toluene conversion as high as 40 %, which rivals traditional chlorination methods.
- Liu, Shouxin,Zhang, Qi,Li, Huiying,Yang, Yihua,Tian, Xia,Whiting, Andrew
-
supporting information
p. 9671 - 9675
(2015/06/30)
-
- Iron catalyzed halogenation of benzylic aldehydes and ketones
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A simple and efficient iron-catalyzed method for chlorination of aromatic carbonyl compounds is reported. By using 4-10 mol% Fe(iii) oxo acetate catalyst, prepared by solid state atmospheric oxidation of Fe(ii) acetate, in combination with triethylsilane and chlorotrimethylsilane, hydrosilylation of benzylic carbonyl compounds with subsequent chlorination is achieved within a few hours at room temperature. This new method is mild and rapid compared to the conventional two step approach involving reduction and chlorination reactions in separate stages. Development of synthetic methodology is also supplemented here by kinetic investigation of the reaction mechanism, which supports the tentative mechanisms suggested previously for similar reactions. This journal is
- Savela, Risto,W?rn?, Johan,Murzin, Dmitry Yu.,Leino, Reko
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p. 2406 - 2417
(2015/04/14)
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- Friedel-crafts reaction of benzyl fluorides: Selective activation of C-f bonds as enabled by hydrogen bonding
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A Friedel-Crafts benzylation of arenes with benzyl fluorides has been developed. The reaction produces 1,1-diaryl alkanes in good yield under mild conditions without the need for a transition metal or a strong Lewis acid. A mechanism involving activation of the C-F bond through hydrogen bonding is proposed. This mode of activation enables the selective reaction of benzylic C-F bonds in the presence of other benzylic leaving groups.
- Champagne, Pier Alexandre,Benhassine, Yasmine,Desroches, Justine,Paquin, Jean-Franois
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supporting information
p. 13835 - 13839
(2015/02/05)
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- Sulfite formation versus chlorination of benzyl alcohols with thionyl chloride
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Recently, we have reported the photolytic decay of a library of para-substituted dibenzylic sulfites in a Srinivasan-Griffin-Rayonet photochemical reactor. In an attempt to synthesize the complete library for that study we discovered that bis(p-methoxybenzyl) sulfite and bis(p-phenoxybenzyl) sulfite could not be formed and only their corresponding benzyl chlorides were synthesized. Thus, sulfite formation versus chlorination of a range of para-substituted benzyl alcohols with thionyl chloride was investigated. Sulfite formation was observed to be parabolically related to Swain and Lupton's Field ?-values while chloride formation was found to be linearly related to Swain and Lupton's Field ?-values.
- Rodriguez, Deana A.,Priefer, Ronny
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p. 3045 - 3048
(2014/05/20)
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- An inexpensive and convenient procedure for chloromethylation of aromatic hydrocarbons by phase transfer catalysis in aqueous media
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Reaction of aromatic hydrocarbons catalyzed by a novel catalytic system consisting of zinc chloride, acetic acid, sulfuric acid and PEG-800 in aqueous media under PTC conditions results in chloromethylation in good to excellent yield.
- Hu, Yu Lin,Lu, Ming,Ge, Qiang,Wang, Peng Cheng,Zhang, Sheng Bin,Lu, Ting Ting
-
experimental part
p. 97 - 102
(2010/08/05)
-
- Microwave assisted solid additive effects in simple dry chlorination reactions with n-chlorosuccinimide
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Solid additives participate in the dry microwave assisted chlorination reaction of N-chlorosuccinimide with the xylenes affecting both yields and chemoselectivities. Total yields can be increased up to nine times for simple alkylaromatics and chemoselectivities can be altered according to the desired ring or α-side chlorination product by choosing the appropriate additive. We believe that in these reactions the solid additives play a very important role by increasing yields and affecting chemoselectivities, as well as behaving as microwave energy absorbers that consequently aid the transfer of heat to the active reagents.
- Bucos, Madalina,Villalonga-Barber, Carolina,Micha-Screttas, Maria,Steele, Barry R.,Screttas, Constantinos G.,Heropoulos, Georgios A.
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experimental part
p. 2061 - 2065
(2010/04/26)
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- Interpretation of retention indices in gas chromatography for establishing structures of isomeric products of alkylarenes radical chlorination
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By an example of previously uncharacterized products obtained by alkylarenes radical chlorination was demonstrated that combination of various interpretation methods applied to the retention indices (RI) in the gas chromatography on the standard nonpolar phases (comparison of RI of products and initial compounds, characteristics of succession of the chromatographic elution of the structural isomers with the use of estimation of molecular dynamic parameters, application of the additive schemes to RI calculation, and using of structural analogy CH3?Cl for testing the results obtained) permitted unambiguous identification of the structure even without data of mass spectrometry.
- Zenkevich
-
p. 270 - 280
(2007/10/03)
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- Antifungal formulation comprising protoberberine derivatives and salts thereof
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The antifungal formulation comprising the novel compounds of the following chemical formulae (I) and (II) exhibit in vitro antifungal activity against fungi including cutaneous filamentous fungus, such as Epidermophyton, Microsporum, Trichophyton, Sporothrix schenckii, Aspergillus or Candida. The formulation of the present invention exhibit in vitro antifungal activity at the concentration of 1-100 mu g/ml. wherein R1, R2, and R4 may be the same or different, and represent C1-C5 alkoxy, R3 represents hydrogen or C1-C10 alkyl, A- represents inorganic acid ion, organic acid ion or halide, R5 represents hydrogen, pyridylmethyl, substituted pyridylmethyl or a group having the following chemical formula(XI) wherein Z1, Z2, Z3, Z4 and Z5 may be the same or different and represent hydrogen, halogen, C1-C5 alkyl, trifluoromethyl, phenyl, substituted phenyl, nitro, C1-C4 alkoxy, C1-C4 alkylamino, acetylamino, C1-C8 trialkyl ammonium, guanidinyl, methylthio, ethylthio, trifluoromethoxy, hydroxy, phenoxy, vinyl, carboxyl and C1-C2 alkoxycarbonyl group.
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-
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- Pharmaceutically available protoberberine salts derivatives, and protoberberine salts derivatives, and protoberberine derivatives and salts thereof
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The novel compounds of the following chemical formulae (I) and (II) exhibit in vitro antifungal activity against fungi including cutaneous filamentous fungus, such as Epidermophyton, Microsporum, Trichophyton, Sporothrix schenckii, Aspergillus or Candida. The compounds of the present invention exhibit in vitro antifungal activity at the concentration of 1-100 μg/ml. STR1 wherein R1, R2, and R4 may be the same or different, and represent C1 -C5 alkoxy, R3 represents hydrogen or C1 -C10 alkyl, A- represents inorganic acid ion, organic acid ion or halide, R5 represents hydrogen, pyridylmethyl, substituted pyridylmethyl or a group having the following chemical formula(XI) STR2 wherein Z1, Z2, Z3, Z4 and Z5 may be the same or different and represent hydrogen, halogen, C1 -C5 alkyl, trifluoromethyl, phenyl, substituted phenyl, nitro, C1 -C4 alkoxy, C1 -C4 alkylamino, acetylamino, C1 -C8 trialkyl ammonium, guanidinyl, methylthio, ethylthio, trifluoromethoxy, hydroxy, phenoxy, vinyl, carboxyl and C1 -C2 alkoxycarbonyl group.
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-
-
- Anodic oxidation of 3-phenylpropionic acid
-
The electrochemical oxidation of 3-phenylpropionic acid has been performed on platinum, graphite and PtO2/Ti anodes. Two types of products have been obtained, either formed by one-electron oxidation, or by two-electron oxidation. The influence of the anode material, current density and solvent nature on the products distribution has been studied. The electrochemical oxidations of 3-(p-t-butylphenyl)propionic, 3,3-d-3-phenylpropionic and 2,2-d-3-phenylpropionic acids have been studied in order to get information concerning the carbonium-type intermediate in the two-electron oxidation. Unlike the chemical generation, the 2-phenylethyl carbocation formed by two-electron oxidation stabilises, leading mainly to rearranged products. The obtained results are in agreement with the assumption that either phenyl or σC-H bond assists the carbocation formation.
- Ro?ca, Sorin,Ungureanu, Mihaela,Stan, Raluca
-
-
- Photolysis of (Arylmethyl)triphenylphosphonium Salts. Substituent, Counterion, and Solvent Effects on Reaction Products
-
Quaternary (arylmethyl)phosphonium salts of the general formula ArCH2-PR3(+)Y(-) (Ar = substituted phenyl or 1-naphthyl; R = phenyl, ferrocenyl, or butyl; Y(-) = BF4(-) or halide) have been photolyzed in acetonitrile or in methanol.Photolysis involved the cleavage of the P-CH2 bond and the products derived from both, the arylmethyl radical and the carbocation, were formed.The proportion of the radical- and carbocation-derived products was determined as a function of substituents in group Ar, of groups R, counterions Y(-), and the solvent.For the nonoxidizable counterion (BF4(-), the proposed mechanism of the reaction involves initial homolysis, followed by the escape of the radical products from a solvent cage, or by the electron transfer from carbon to phosphorus, yielding the corresponding arylmethyl carbocation.The latter can either react with the solvent to form the observed carbocation-derived product or can undergo recombination with the tertiary phosphine formed to yield the starting phosphonium ion.Some indication of the "inverted substituent effect" resulting from the inhibition of single electron transfer from an easily oxidized radical was obtained.For the oxidizable counterions (halides), an additional pathway is suggested, that involves electron transfer from the anion, yielding the arylmethyl radical and the phosphine, thus decreasing the ionic/radical products ratio.
- Imrie, C.,Modro, T. A.,Rohwer, E. R.,Wagener, C. C. P.
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p. 5643 - 5649
(2007/10/02)
-
- AN IMPROVED METHOD FOR THE CONVERSION OF CERTAIN AROMATIC CARBOXYLIC ACIDS INTO BENZYLIC CHLORIDES
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A novel one-pot procedure, which affords benzylic chlorides in about 70percent yield, involves reduction of benzoyl chlorides by aqueous sodium borohydride as a key step.
- Costello, Alan T.,Milner, David J.
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p. 1173 - 1176
(2007/10/02)
-
- Micellar Systems as ''Supercages'' for Reactions of Geminate Radical Pairs. Magnetic Effects
-
The photochemistry of dibenzyl ketone (DBK) and other molecules capable of producing benzyl radicals and substituted benzyl radicals has been investigated in micellar systems.The cage effect (percent of unscavengeable radical pairs produced by photolysis) was measured under a variety of conditions, and the results are compared with those obtained in homogeneous organic solvents.For example, parameters such as mean occupancy of ketone, detergent type and concentration, O2 concentration, additives, temperature, applied magnetic field, and pressure have been varied and investigated as to their influence on the magnitude of cage effect.In addition to modifying its environment, structural modification of the DBK by incorporation of 2H and 13C isotopes, hydrophobic groups, and heavy atoms was performed to investigate the impact of these variations on the cage effect in micellar systems.Isotopic substitution of 2H or 13C leads to results on both the quantum yields for reactions and on the percent cage that were consistent with expectations of magnetic isotope effects.Hydrophobic groups substituted in the 4-position of DBK were found to cause a substantial increase in the cage effect and yet retain the magnetic-field-dependent character found in the parent DBK.Incorporation of Br in the 4-position of DBK was found to enhance the cage effect but at the same time cause the cage effect to become magnetic field independent.Substitution of α-naphthyl for phenyl in DBK also produced magnetic-field-independent behavior, in addition to a dramatic decrease in the efficiency of photolysis.
- Turro, Nicholas J.,Weed, Gregory C.
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p. 1861 - 1868
(2007/10/02)
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- A SIMPLE AND INEXPENSIVE PROCEDURE FOR CHLOROMETHYLATION OF CERTAIN AROMATIC COMPOUNDS
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Reaction of a range of aromatic compounds with methoxyacetyl chloride and aluminium chloride in either nitromethane or carbon disulphide results in chloromethylation in good to excellent yield.
- McKillop, Alexander,Madjdabadi, Fereidon Abbasi,Long, David A.
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p. 1933 - 1936
(2007/10/02)
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- 4-Amino-4-arylcyclohexanones and Their Derivatives, a Novel Class of Analgesics. 1. Modification of the Aryl Ring
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Investigation of central nervous system activity of phenylcyclohexylamines was continued by preparation of "reversed" analogues.Following the unexpected finding of analgesic activity with 1-(dimethylamino)-1-phenylcyclohexylamine, the SAR of the series was investigated.Synthesis starts by double Michael reaction of acrylate on arylacetonitriles.Following cyclization, decarboxylation, ketalization, and saponification, the geminally substituted acid is rearranged to the isocyanate by means of (C6H5O)2PON3.Isocyanates were then converted to the title compounds.Analgesic activity is very sensitive to the nature and position of the substituent on the aromatic ring.The most potent compounds in this series (p-CH3, p-Br) showed 50percent the potency of morphine.Deletion of the ring oxygen abolishes activity.
- Lednicer, Daniel,VonVoigtlander, Philip F.,Emmert, D. Edward
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p. 424 - 430
(2007/10/02)
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- 1-[2-(1-Adamantyl)-2-(R-thio)ethyl]imidazoles and 1-[2-(1-adamantyl)-2-(R-oxy)ethyl]imidazoles
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Compounds of the formula STR1 wherein R is alkyl, cycloalkyl, cycloalkyl lower alkyl, phenyl or phenyl lower alkyl, said phenyl and phenyl lower alkyl optionally substituted on the phenyl ring with one or more substituents independently selected from the group consisting of halo, lower alkyl and trifluoromethyl; and X is oxygen or sulfur with the proviso that X is not oxygen when R is phenyl or substituted phenyl; and the antimicrobial acid addition salts thereof are useful as antifungal, antibacterial and antiprotozoal agents.
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