- Atmospheric oxidation of poly(oxyethylene) alcohols. Identification of ethoxylated formates as oxidation products and study of their contact allergenic activity
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Ethoxylated alcohols are widely used as surfactants. In the present study we have continued our investigations on the degradation with time upon air exposure of the ethoxylated alcohols at normal storage and handling. As a result, a new group of ethoxylated formates with the general formula C12H25(OCH2CH2)(n)OCHO (n = 0-4) was identified in C12H25(OCH2CH2)5OH stored and handled at room temperature. To facilitate the identification work, reference compounds were synthesized. The formates showed no allergenic activity in the sensitization studies performed. In previous investigations on the same ethoxylated alcohol, we have identified formaldehyde and ethoxylated aldehydes among the oxidation products formed. Formaldehyde is a common contact allergen, and the ethoxylated aldehydes were shown to have a sensitizing capacity of the same magnitude as formaldehyde. The instability of the ethoxylated alcohols and formation of oxidation products may give an allergenic contribution to hand eczema caused by work with water and surfactants. To investigate the clinical significance in man an appropriate diagnostic patch testing in exposed humans is required.
- Bergh, Margareta,Shao, Li Ping,Magnusson, Kerstin,Gaefvert, Elisabeth,Nilsson, J. Lars G.,Karlberg, Ann-Therese
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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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- 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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- Method for preparing formate-type compound
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The invention discloses a method for preparing a formate-type compound. The method comprises the following steps of: adopting an alcohol-type compound and 1,3-dihydroxyacetone as reaction raw materials, and under the existence of a composite catalyst and an oxidant, reacting for 2-48 hours in a reaction medium in a reactor at a reaction temperature of 25-100 DEG C so as to obtain the formate-typecompound. The method disclosed by the invention is simple, and is mild in reaction condition, and by the method, a target product can be obtained by low cost and high yield; the used catalyst has highcatalytic activity, and is easily separated from a reaction system to be repeatedly used; the whole process is environment-friendly, and the reaction raw material (1,3-dihydroxyacetone) is easily converted from a side product (glycerol) of biodiesel, so that the utilization of the glycerol is promoted.
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Paragraph 0039; 0047; 0048
(2018/07/30)
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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
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supporting information
p. 7410 - 7416
(2018/04/30)
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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.
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supporting information
p. 10145 - 10149
(2016/08/16)
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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.
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Page/Page column 50; 132; 134
(2017/01/02)
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- Formylation of amines catalysed by protic ionic liquids under solvent-free condition
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A fast, efficient and simple route for the N-formylation of amines has been developed by treating amines with 85% formic acid at 70°C in the presence of 5 mol % of protic ionic liquid as catalyst under solvent-free condition. This method provides a green and much improved protocol over the existing methods.
- Majumdar, Swapan,De, Jhinuk,Hossain, Jewel,Basak, Ajoy
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p. 262 - 266
(2013/02/22)
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- One-pot synthesis of isocyanides from alcohols
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A one-pot reaction of alcohols with trimethylsilyl cyanide and methanesulfonic acid with subsequent neutralization by triethylamine and dehydration by tosyl chloride and pyridine gave the corresponding isocyanides in moderate-to-high yields. This method was used to synthesize tertiary and benzylic isocyanides from the corresponding alcohols. Georg Thieme Verlag Stuttgart · New York.
- Okada, Iku,Kitano, Yoshikazu
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body text
p. 3997 - 4002
(2012/01/06)
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- Copper-catalyzed oxidative cleavage of carbon-carbon double bond of enol ethers with molecular oxygen
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A novel CC bond cleavage reaction of aromatic enol ethers (1) to give ketones (2) using molecular oxygen as oxidant is described. Among the examined catalysts (Cu(II), Pd(II), Ru(II), and H+), CuCl2 exhibited the highest activity. The reaction proceeded smoothly with several kinds of substrates.
- Tokunaga, Makoto,Shirogane, Yuki,Aoyama, Hiroshi,Obora, Yasushi,Tsuji, Yasushi
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p. 5378 - 5382
(2007/10/03)
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- Reptilian chemistry: volatile compounds from paracloacal glands of the American crocodile (Crocodylus acutus).
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The secretion of the paracloacal glands of the American crocodile (Crocodylus acutus) contains over 80 lipophilic compounds, including saturated and unsaturated long-chain alcohols along with their formic, acetic, and butyric acid esters, and several isoprenoids. Most of these compounds were identified on the basis of mass spectra, obtained by GC-MS. In addition, identification of the major components was supported by infrared spectra obtained by GC-FTIR. Major differences are indicated in the composition of the paracloacal gland secretion of C. acutus and that of another crocodylid, the African dwarf crocodile (Osteolaemus tetraspis).
- Garcia-Rubio, Silvina,Attygalle, Athula B,Weldon, Paul J,Meinwald, Jerrold
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p. 769 - 781
(2007/10/03)
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- Selective formylation of alcohols in the presence of phenols with chloral
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Primary and secondary alcohols were formylated selectively in the presence of phenols by stirring with chloral in acetone over anhydrous K2CO3 at ambient temperatures in high yields.
- Ram, Ram N,Meher, Nabin Kumar
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p. 2997 - 3001
(2007/10/03)
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- Conversion of alkyl halides into the corresponding alcohols under mild reaction conditions
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Reaction of primary, cyclopentyl, allyl and arylmethyl halides, but not an acyclic secondary halide or a tertiary halide, in acetone or tetrahydrofuran with the formate form of a commercial anion exchange resin gave formate esters in good yields. The formates were hydrolysed efficiently to the corresponding alcohols by a brief treatment with hydrochloric acid. Reaction of primary alkyl bromides or iodides, secondary alkyl bromides, cinnamyl and arylmethyl halides in tetrahydropyran or 1,4-dioxane with the bicarbonate form of the same anion-exchange resin gave the corresponding alcohols directly in good yields. This latter reaction can be carried out successfully in the presence of ester or amide groups.
- Ruddick, Clare L.,Hodge, Philip,Houghton, Mark P.
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p. 1359 - 1362
(2007/10/03)
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- OXIDATIVE SUBSTITUTION OF PhTe AND PhSe MOIETIES IN ALKYL PHENYL TELLURIDES AND SELENIDES LEADING TO ESTERS AND ALCOHOLS
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Oxidation of alkyl phenyl tellurides and/or selenides with sodium periodate (NaIO4) in aqueous acetic acid or with metachloroperbenzoic acid (MCPBA) in N,N-dimethylformamide or N,N-dimethylacetamide affords a mixture of the corresponding alkyl esters (acetates or formates) and/or alcohols in 20-94percent yield under mild conditions (at 20-80 deg C for 0.5-24 h).
- Hirai, Yasuyuki,Ohe, Kouichi,Toshimitsu, Akio,Uemura, Sakae
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p. 173 - 176
(2007/10/02)
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- Facile Acylation of Aclohols Using Esters and Silica Gel-supported Metallic Sulphates and Hydrogen Sulphates
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Alcohols are acylated in a quite simple operation in high yields by being heated in esters in the presence of silica gel-supported metallic sulphates and hydrogen sulphates, such as Ce(SO4)2, Ti(SO4)2, Fe2(SO4)3, and NaHSO4.
- Nishiguchi, Takeshi,Taya, Hisachi
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p. 172 - 173
(2007/10/02)
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- O-ALKYLATION D'AMIDES A L'AIDE DE SELS D'ALKYLDIPHENYLSULFONIUM
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O-Alkylation of amides and ureas was easily accomplished with alkyldiphenylsulphonium salts.These alkylating agents are readily available, often crystalline, and non-hygroscopic.They are somewhat less powerful than oxonium salts but are not limited to methyl and ethyl groups.The following order of reactivities was observed: PhCH2S(+)Ph2EtS(+)Ph2Et2SO4MeS(+)Ph2.Benzylation proceeded under very mild conditions (room temperature).The counterion and solvent have no significant influence on the reaction rate.Sulphonium salts where the leaving group is a dialkyl sulphide are much less active as alkylating agents.New alkoxymethyleneiminium salts have been prepared in this way in yields above 70 percent.
- Julia, M.,Mestdagh, H.
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p. 433 - 442
(2007/10/02)
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