- Drastic fluorine effect: Complete reversal of the selectivity in the Au-catalyzed hydroalkoxylation reaction of fluorinated haloalkynes
-
The gold-catalyzed hydration reaction of haloalkynes is highly regioselective producing 2-halomethylketones as the sole products. Herein, we document a drastic fluorine effect where the reaction of 1-halo-3,3-difluoroalkynes as substrates leads to a complete reversal of selectivity and produces 3,3-difluoroesters as the unique products.
- Cloutier, Mélissa,Mamone, Marius,Paquin, Jean-Fran?ois
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p. 5969 - 5972
(2020/06/04)
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- An Asymmetric Suzuki-Miyaura Approach to Prostaglandins: Synthesis of Tafluprost
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We report the catalytic asymmetric synthesis of Tafluprost (1), a prostaglandin analogue. This synthesis demonstrates a new approach to prostaglandins involving symmetrization and desymmetrization of a racemic precursor to control the absolute and relative stereochemistry of the cyclopentyl core. Key steps include a diastereo- and enantioselective Rh-catalyzed Suzuki-Miyaura reaction of a racemic bicyclic allyl chloride and an alkenyl boronic acid and a regio- and diastereoselective Pd-catalyzed Tsuji-Trost reaction with an enolate surrogate.
- Fletcher, Stephen P.,Goetzke, F. Wieland,Ku?era, Roman
-
supporting information
(2020/04/09)
-
- COMPOUND USED AS AUTOPHAGY REGULATOR, AND PREPARATION METHOD THEREFOR AND USES THEREOF
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It is related to compounds used as autophagy modulators and a method for preparing and using the same, specifically providing a compound of general formula (I), or pharmaceutically acceptable salts thereof, which is a type of autophagy modulators, particularly mammalian ATG8 homologues modulators.
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- Gold(III)-Catalyzed Intermolecular Oxidation-Cyclization of Ynones: Access to 4-Substituted Chroman-3-ones
-
A synthesis of 4-substituted chroman-3-one derivatives has been developed through a gold(III) catalyzed oxidation-cyclization of ynones in good to excellent yield using easily prepared substrates. A broad range of synthetically useful functional groups (halide, alkene, alkyne, phenolic hydroxyl) were tolerated. Further application of this method paves a new way to prepare the skeleton of oblarotenoids. A cascade oxidative cyclization for construction of pyrano[2,3-c]chromen-1(5H)-one derivatives is also presented. (Figure presented.).
- Li, Jian,Yang, Fang,Ma, Yang-Ting,Ji, Kegong
-
supporting information
p. 2148 - 2153
(2019/03/28)
-
- Palladium-Catalyzed C(sp3)?H Arylation of Primary Amines Using a Catalytic Alkyl Acetal to Form a Transient Directing Group
-
C?H Functionalization of amines is a prominent challenge due to the strong complexation of amines to transition metal catalysts, and therefore typically requires derivatization at nitrogen with a directing group. Transient directing groups (TDGs) permit C?H functionalization in a single operation, without needing these additional steps for directing group installation and removal. Here we report a palladium catalyzed γ-C?H arylation of amines using catalytic amounts of alkyl acetals as transient activators (e.g. commercially available (2,2-dimethoxyethoxy)benzene). This simple additive enables arylation of amines with a wide range of aryl iodides. Key structural features of the novel TDG are examined, demonstrating an important role for the masked carbonyl and ether functionalities. Detailed kinetic (RPKA) and mechanistic investigations determine the order in all reagents, and identify cyclopalladation as the turnover limiting step. Finally, the discovery of an unprecedented off-cycle free-amine directed ?-cyclopalladation of the arylation product is reported.
- St John-Campbell, Sahra,Ou, Alex K.,Bull, James A.
-
supporting information
p. 17838 - 17843
(2018/11/23)
-
- Chemoselective deoxygenation of ether-substituted alcohols and carbonyl compounds by B(C6F5)3-catalyzed reduction with (HMe2SiCH2)2
-
B(C6F5)3-catalyzed deoxygenation of ether-substituted alcohols and carbonyl compounds has been developed using (HMe2SiCH2)2 as the reductant. This unique reagent shows distinct superiority over traditional one silicon-centered hydrosilanes, giving the corresponding alkanes in high yields with good tolerance of ethers, aryl halides and alkenes. The control experiments suggest that (HMe2SiCH2)2 might facilitate the approach in an intramolecular Si/O activation manner.
- Yang, Wenyu,Gao, Lu,Lu, Ji,Song, Zhenlei
-
supporting information
p. 4834 - 4837
(2018/05/23)
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- HETEROCYCLIC LIPXON ANALOGS AND USES THEROF
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The present invention relates to a compound of formula (I): wherein L is an optionally substituted heterocyclic group excluding unsubstituted monocyclic pyridine groups; wherein a is 0, 1 or 2; wherein R1 is H or with R2 is a bond; wherein R2 is an optionally substituted alkoxy or aryloxy group, or with R1 forms a bond; wherein R3 is an optionally substituted alkyl group; and wherein R4 is CH2, CMe2 or O. Such compounds may be used in the treatment or prophylaxis of a disease or condition in which inhibition of acute inflammation and/or promotion of its resolution and/or suppression of fibrosis.
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- Reactions of peroxide products of ozonolysis of allyl ethers/esters in the AcOH-CH2Cl2 system on treatment with semicarbazide hydrochloride
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Background: A one-pot method for the preparation of the corresponding alkoxy acetic acids by low-temperature ozonolysis of allyl ethers/esters followed by treatment with semicarbazide hydrochloride has been suggested. The reaction occurs via formation of acetoxyhydroperoxide, subsequent reduction of which depends on the process temperature and the nature of the starting substrate. Objective: The article is aimed at the development of one-pot method for obtaining practically important alkoxy acetic acids, because the ozonolytic cleavage of a ?=? double bond is the key step in full syntheses of many biologically active compounds. Methods: We used a low temperature ozonolysis of functionally substituted olefins in the system acetic acid-methylene dichloride followed by reduction of semicarbazide hydrochloride. To create a method we have used available allyl ethers/esters as starting materials. Results: We investigated reaction of the peroxide products of ozonolysis of monoallyl ethers, ester and diallyl ethers in an AcOH/CH2Cl2 mixture on treatment with semicarbazide hydrochloride at various temperatures. We have discovered that the selectivity of reduction of acetoxyhydroperoxide formed at the first stage depends both on the process temperature and on the nature of the starting substrate. A decrease in temperature favors acid hydrolysis and formation of a carboxylic acid. Conclusion: We have proposed a simple and highly efficient one-pot method for the preparation alkoxy acetic acids without isolation of intermediate peroxides.
- Raskil'dina, Gulnara Z.,Legostaeva, Yuliya V.,Garifullina, Liliya R.,Sultanova, Rimma M.,Ishmuratov, Gumer Y.,Zlotskii, Simon S.
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p. 652 - 656
(2017/01/13)
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- Pyrazolo[3,4-c]pyridine derivative
-
The invention relates to a pyrazolo[3,4-c]pyridine derivative. The invention relates to a compound represented by a formula (I), a tautomer thereof, an optical isomer thereof or a pharmaceutically acceptable salt thereof, wherein the formula (I) is shown in the description, and Z, X, RNc, RNd, RNe and RNf are defined according to the claim 1. The invention further relates to the pharmaceutical composition contain the compound. The invention further relates to use of the compound or the pharmaceutical composition in preparing a drug for preventing and/or treating a disease which inhibits positive influence of an Xa factor, particularly use in preparing the drug for preventing and/or treating the disease which inhibits positive influence of the Xa factor under the condition of low hemorrhage risk.
- -
-
Paragraph 0338; 0339; 0340
(2016/10/08)
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- Synthesis of 2-tetralone derivatives by Bi(OTf)3-catalyzed intramolecular hydroarylation/isomerization of propargyl alcohols
-
Compared to 1-tetralones, 2-tetralones are expensive, less stable, and difficult to synthesize. A concise Bi-catalyzed method was developed for the synthesis of 2-tetralones from 5-phenylpent-1-yn-3-ol derivatives. Diverse 2-tetralones were obtained in moderate to good yields under mild conditions.
- Yun, Jihee,Park, Jungmin,Kim, Jaehyun,Lee, Kooyeon
-
p. 1045 - 1048
(2015/02/19)
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- New class of bioluminogenic probe based on bioluminescent enzyme-induced electron transfer: BioLeT
-
Bioluminescence imaging (BLI) has advantages for investigating biological phenomena in deep tissues of living animals, but few design strategies are available for functional bioluminescent substrates. We propose a new design strategy (designated as bioluminescent enzyme-induced electron transfer: BioLeT) for luciferin-based bioluminescence probes. Luminescence measurements of a series of aminoluciferin derivatives confirmed that bioluminescence can be controlled by means of BioLeT. Based on this concept, we developed bioluminescence probes for nitric oxide that enabled quantitative and sensitive detection even in vivo. Our design strategy should be applicable to develop a wide range of practically useful bioluminogenic probes.
- Takakura, Hideo,Kojima, Ryosuke,Kamiya, Mako,Kobayashi, Eiji,Komatsu, Toru,Ueno, Tasuku,Terai, Takuya,Hanaoka, Kenjiro,Nagano, Tetsuo,Urano, Yasuteru
-
supporting information
p. 4010 - 4013
(2015/04/14)
-
- A practical in situ generation of the schwartz reagent. reduction of tertiary amides to aldehydes and hydrozirconation
-
A new, highly efficient in situ protocol (Cp2ZrCl2/LiAlH(OBu-t)3) is described for the generation of the Schwartz reagent which provides a convenient method for the amide to aldehyde reduction and the regioselective hydrozirconation-iodination of alkynes and alkenes. Highlighted are chemoselective reductions of benzamides derived by directed ortho metalation (DoM) chemistry, allowing the synthesis of valuable 1,2,3-substituted benzaldehydes. The single-step, three-component process proceeds in a very short reaction time, shows excellent functional group compatibility, and uses inexpensive and long-storage stable reducing reagents.
- Zhao, Yigang,Snieckus, Victor
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p. 390 - 393
(2014/04/03)
-
- Catalysis through temporary intramolecularity: Mechanistic investigations on aldehyde-catalyzed cope-type hydroamination lead to the discovery of a more efficient tethering catalyst
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Mechanistic investigations on the aldehyde-catalyzed intermolecular hydroamination of allylic amines using N-alkylhydroxylamines are presented. Under the reaction conditions, the presence of a specific aldehyde catalyst allows formation of a mixed aminal intermediate, which permits intramolecular Cope-type hydroamination. The reaction was determined to be first-order in both the aldehyde catalyst (α-benzyloxyacetaldehyde) and the allylic amine. However, the reaction displays an inverse order behavior in benzylhydroxylamine, which reveals a significant off-cycle pathway and highlights the importance of an aldehyde catalyst that promotes a reversible aminal formation. Kinetic isotope effect experiments suggest that hydroamination is the rate-limiting step of this catalytic cycle. Overall, these results enabled the elaboration of a more accurate catalytic cycle and led to the development of a more efficient catalytic system for alkene hydroamination. The use of 5-10 mol % of paraformaldehyde proved more effective than the use of 20 mol % of α-benzyloxyacetaldehyde, leading to high yields of intermolecular hydroamination products within 24 h at 30 °C.
- Guimond, Nicolas,MacDonald, Melissa J.,Lemieux, Valerie,Beauchemin, Andre M.
-
supporting information
p. 16571 - 16577,7
(2020/09/15)
-
- Selective formation of six-membered oxa- and carbocycles by the In(III)-activated ring closure of acetylenic substrates
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Fifteen examples are disclosed of efficient In(III)-catalyzed six-membered ring closure leading to bi-, tri-, and tetracyclic products.
- Qiu, Wen-Wei,Surendra, Karavadhi,Yin, Liang,Corey
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supporting information; experimental part
p. 5893 - 5895
(2011/12/16)
-
- Recycling of osmium catalyst in oxidative olefin cleavage: A chemoentrapment approach
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A new chemoentrapment strategy for recycling osmium in the catalytic olefin cleavage reaction is reported. The new strategy utilizes KOH/i-PrOH to generate water-soluble Os(VI) species as a recyclable metal catalyst after the oxidative cleavage reaction. For the recycling of the catalyst, NaIO4- NaClO2 was found to be the best combination of secondary oxidants and acetonitrile-water was chosen as an optimal solvent for the best recycling results. The new method allows for an efficient recycling of osmium in the reactions involving mono- and di-substituted olefins with 1 mol % of OsO 4 without any significant side reactions and loss of yield.
- Kim, Seyoung,Chung, Jooyoung,Kim, B. Moon
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experimental part
p. 1363 - 1367
(2011/03/22)
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- Schwartz Reagents: Methods of In Situ Generation and Use
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Embodiments of the invention provide a method of using Schwartz Reagent, Cp2Zr(H)Cl, without accumulating or isolating it. Methods provide mixtures of Cp2ZrCl2, reductants that selectively reduce Cp2ZrCl2, and substrates. After reaction of Cp2ZrCl2 and the reductant, an intermediate reduction product is formed, apparently Schwartz Reagent. The in situ Schwartz Reagent then selectively reduces certain functional groups on the substrate. Substrates include tertiary amides, tertiary benzamides, aryl O-carbamates, and heteroaryl N-carbamates, which are reduced to aldehydes, benzaldehydes, aromatic alcohols, and heteroaromatics, respectively. Compared to prior methods, reagents are inexpensive and stable, reaction times are short, and reaction temperature in certain cases is conveniently room temperature. It has been estimated that using the in situ method described herein instead of synthesized or commercially obtained Schwartz Reagent provides a 50% reduction in cost.
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Page/Page column 7; 12
(2010/06/19)
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- One-pot synthesis of imidazole-4-carboxylates by microwave-assisted 1,5-electrocyclization of azavinyl azomethine ylides
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Diversely functionalized imidazole-4-carboxylates were synthesized by microwave-assisted 1,5-eletrocyclization of 1,2diaza-l,3-diene-derived azavinyl azomethine ylides. 1,2-Diaza-1,3-dienes were treated with primary aliphatic or aromatic amines and subjected to microwave irradiation in the presence of aldehydes. 3-Alkyl- and 3-arylimidazole-4-carboxylates were prepared in good yields through a one-pot multicomponent procedure. Modulation of the substituents at C-2, N-3, and C-5 was possible, and 2-unsubstituted imidazoles were obtained when paraformaldehyde was used.
- Preti, Lisa,Attanasi, Orazio A.,Caselli, Emilia,Favi, Gianfranco,Ori, Claudia,Davoli, Paolo,Felluga, Fulvia,Prati, Fabio
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supporting information; experimental part
p. 4312 - 4320
(2010/10/21)
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- Synthesis of aryloxyacetaldehydes and N-(aryloxyethyl)cyclohexanamine hydrochloroides
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Oxidation of 2-(aryloxymethyl)oxiranes with periodic acid gave a series of aryloxyacetaldehydes which reacted with cyclohexylamine in THF, and subsequent reduction of Schiff bases thus obtained with sodium tetrahydridoborate resulted in the formation of the corresponding secondary amines which were isolated and characterized as hydrochlorides.
- Shapenova,Belyatskii,Panicheva
-
experimental part
p. 1017 - 1020
(2010/10/21)
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- MEDICAMENTS
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A compound of formula (I) is described: wherein R1 and R2 are as defined in the text and wherein the compounds are intended for use in treating medical conditions characterized by an imbalance in dopamine receptor activity.
- -
-
Page/Page column 97
(2009/06/27)
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- INDAZOLYL ESTER AND AMIDE DERIVATIVES FOR THE TREATMENT OF GLUCOCORTICOID RECEPTOR MEDIATED DISORDERS
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Compounds of formula (I): The present invention relates to novel indazolyl ester or amide derivatives, to pharmaceutical compositions comprising such derivatives, to processes for preparing such novel derivatives and to the use of such derivatives as medicaments
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- Tishchenko reactions of aldehydes promoted by diisobutylaluminum hydride and its application to the macrocyclic lactone formation
-
Aliphatic aldehydes react with catalytic amount of Dibal-H in n-pentane to give the corresponding Tishchenko products in good to excellent yields. On contrary, α-silyloxy aldehydes give α-silyloxy ketones via Oppenauer oxidation under similar condition. Tishchenko reaction of ω-alkene aldehydes followed by RCM and hydrogenation affords a convenient method to prepare the 11-37 membered macrocyclic lactones.
- Hon, Yung-Son,Wong, Ying-Chieh,Chang, Chun-Ping,Hsieh, Cheng-Han
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p. 11325 - 11340
(2008/03/12)
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- Wacker oxidation of terminal olefins in a mixture of [bmim][BF4] and water
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A simple and efficient PdCl2/CuCl catalyzed oxidation of alkenes has been successfully developed using a mixture of water and the ionic liquid [bmim][BF4] as solvent. Starting from various types of terminal olefins, the corresponding ketones have been prepared under mild reaction conditions and obtained in good to excellent yields after a simple extraction with diethyl ether. Furthermore, it was possible to recycle and reuse the ionic liquid and the catalytic system.
- Ansari,Joyasawal, Sipak,Gupta, Manoj K.,Yadav,Gree
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p. 7507 - 7510
(2007/10/03)
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- ISOQUINOLINE-5-SULFONIC ACID AMIDES AS INHIBITORS OF AKT (PROTEIN KINASE B)
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The present invention relates to compounds Formula (I): as inhibitors of AKT activity, which are useful for the treatment of susceptible neoplasms and viral infections.
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- One step hair coloring compositions using salts
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A hair coloring composition comprising the following two compositions which are mixed just prior to application to the hair: (a) a composition comprising a water-soluble peroxygen oxidizing agent; and (b) a composition comprising one or more oxidative hair coloring agents selected from the group consisting of an aromatic diamine, an amino phenol, a naphthol, a polyhydric phenol, a catechol and mixtures thereof; wherein the composition comprising one or more oxidative hair coloring agents further comprises al least one water soluble carbonate releasing salts; and optionally a water soluble ammonium salt, is described.
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-
-
- TEMPO-mediated environmentally benign oxidation of primary alcohols to carboxylic acids with poly[4-(diacetoxyiodo)styrene]
-
An operationally simple and environmentally benign oxidation of primary alcohols to the corresponding carboxylic acids with a TEMPO-mediated poly[4-(diacetoxyiodo)styrene] system in acetone and water was carried out.
- Tashino, Yousuke,Togo, Hideo
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p. 2010 - 2012
(2007/10/03)
-
- Stereochemistry of the conversion of 2-phenoxyethanol into phenol and acetaldehyde by Acetobacterium sp.
-
The conversion of 2-phenoxyethanol to phenol and acetate by the anaerobic bacterium Acetobacterium sp. strain LuPhet1 proceeds through acetaldehyde with concomitant migration of a H-atom from C(1) to C(2) of the glycolic moiety. Separate feeding experiments with (R)- and (S)-2-phenoxy(1- 2H)ethanol, prepared via chemoenzymatic syntheses, indicate that the H-atom involved in the 1,2-shift is the pro-S one of the enantiotopic couple of the alcohol function.
- Speranza, Giovanna,Mueller, Britta,Orlandi, Maximilian,Morelli, Carlo F.,Manitto, Paolo,Schink, Bernhard
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p. 2629 - 2636
(2007/10/03)
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- Transition metal complexes as dye forming catalysts in hair coloring compositions
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A hair coloring composition comprising a first composition which comprises: (a) a dye forming transition metal salt or complex; which is first applied to the hair; and a second composition which comprises the following two compositions which are mixed just prior to application to the hair: (a) a composition comprising a water-soluble peroxygen oxidizing agent; and (b) a composition comprising one or more oxidative hair coloring agents selected from the group consisting of an aromatic diamine, an aminophenol, a polyhydric phenol a catechol and mixtures thereof.
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-
- New version of the TEMPO-based catalytic system for the oxidation of alcohols to aldehydes
-
A new chemoselective catalytic system for the title oxidation was developed using methyltrioxorhenium (3 mol%), KBr (10 mol%) and TEMPO (3 mol%) as co-catalysts and Oxone as a terminal oxidant.
- Kowalczyk,Skarzewski
-
p. 1413 - 1417
(2007/10/03)
-
- Imidazo heterocyclic compounds
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A novel class of imidazo heterocyclic compounds, pharmaceutical compositions comprising them and use thereof in the treatment and/or prevention of diseases and disorders related to the histamine H3 receptor. More particularly, the compounds are useful for the treatment and/or prevention of diseases and disorders in which an interaction with the histamine H3 receptor is beneficial.
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-
- Oxoammonium salts. Part 8: Oxidations in base: Oxidation of O-1 unprotected monosaccharides to lactones using 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate
-
The oxidant, 4-acetylamino-2,2,6,6-tetramethylpiperidine-oxoammonium tetrafluoroborate in pyridine/CH2Cl2, is reported to be an excellent reagent for the conversion of hemiacetals to lactones. Specifically, the conversion of 1-O unprotected sugars to their corresponding aldonolactones is achieved in high yields. The basic reaction conditions partially overcome some disadvantages reported for oxoammonium-type oxidants, namely the inability to run the reaction in the presence of acid-labile groups and in the presence of β-oxygens.
- Merbouh, Nabyl,Bobbitt, James M.,Brückner, Christian
-
p. 8793 - 8796
(2007/10/03)
-
- Oxoammonium salts. 6. 4-Acetylamino-2,2,6,6-tetramethylpiperidine-1- oxoammonium perchlorate: A stable and convenient reagent for the oxidation of alcohols. Silica gel catalysis
-
4-Acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium perchlorate, 1, is a stable, nonhygroscopic oxoammonium salt that is easily prepared and can be used for the oxidation of alcohols to ketones or aldehydes in near quantitative yields. The reaction is colorimetric, does not require anhydrous conditions, does not involve heavy metals, and can be carried out conveniently. Furthermore, the oxidant can be easily regenerated. The oxidation is somewhat specific in that the relative reactivities of an allyl alcohol (geraniol), benzaldehyde, and 1-decanol are about 100:1:0.1. The reaction is catalyzed by silica gel.
- Bobbitt, James M.
-
p. 9367 - 9374
(2007/10/03)
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- A new route to amino-2-propanol structures with adrenergic β-blocker activity using low valent titanium
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Amino-2-propanol structures can be obtained by addition to dibenzyl acetals of in situ generated dihalocarbenes using LTV (Low Valent Titanium). This methodology can be used to obtain adrenergic β-blockers with amino-2-propanol structure. Tetrahalomethane are the best dihalocarbene precursors. The yields obtained using halofluromethanes can be increased by addition of carbontetrachloride. A process that can imply halogen transfer may be proposed.
- Bermudez,Del Campo,Sinisterra,Llama
-
p. 4137 - 4140
(2007/10/03)
-
- Ozonolysis of Olefins VIII [1]. Synthesis of Phenoxyacetaldehydes by Ozonolysis of Allylphenylethers
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A new route for the preparation of a series of phenoxyacetaldehydes (2a-j) which are useful intermediates or products, is described. It starts from the easily available allylphenylethers 1a-j which are ozonized at -40°C and further treated with dimethylsulfide to give solutions of the corresponding phenoxyacetaldehydes 2a-j; these are purified by column chromatography. Reaction of 2a-j with 1-methyl-1-phenylhydrazine leads to the corresponding hydrazones 3a-c, 3e-g, 3i, and 3j. The aldehydes can also be transformed into the stable dimethylcetals 4a, 4e, 4h, and 4i by reaction with trimethyl orthoformate.
- Jellen,Mittelbach,Junek
-
p. 167 - 172
(2007/10/03)
-
- DEHYDROGENATION OF SUBSTITUTED ALCOHOLS TO ALDEHYDES ON ZINC OXIDE-CHROMIUM OXIDE CATALYSTS
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Sixteen primary alcohols of the structure RCH2OH (R = CH3, C2H5, (CH3)2CH, (CH3)3CCH2, HOCH2, CH3OCH2, C6H5, C6H5CH2, C6H5OCH2, ClCH2, BrCH2, F3C, CNCH2, (CH3)2NCH2, (C2H5)2NCH2 and tetrahydrofurfuryl) were explored for the possibility of obtaining the corresponding aldehydes by dehydrogenation on solid catalysts.Various catalysts were tested and two zinc oxide-chromium oxide catalysts were selected for further work because their activity and selectivity was satisfactory; moreover, the selectivity could be improved by addition of sodium into the catalysts and of water into the feed.The reaction was performed in the temperature range 250 - 450 deg C and at atmospheric pressure. 2-Chloroethanol, 2-bromoethanol, ethylene glycol, 2-cyanoethanol and 2-(N,N-diethylamino)ethanol decomposed and deactivated the catalyst.The other alcohols were studied from the point of kinetics of dehydrogenation, which was described by a Langmuir-Hinshelwood type rate equation (3), and of substituent effects on rate, which were correlated by Taft equation (1) with the slope ρ* = -1.46.The preparative value of catalytic dehydrogenation for obtaining substituted aldehydes was confirmed by prolonged runs and isolation of the aldehydic product by distillation using as the feeds 2-methoxyethanol and 2-(N,N-dimethylamino)ethanol, respectively.
- Gulkova, Daniela,Kraus, Milos
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p. 2215 - 2226
(2007/10/02)
-
- New non-proteogenic aminoacids bearing an enol aryl-ether moiety
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Aminoacids bearing an enol aryl-ether moiety have been synthesized by a new method allowing a great versatility in the introduction of N-protective groups and enol ether functions. This method involves a Wittig-Horner condensation affording alpha, beta-dehydrohomoserine ether derivatives, followed by a regio and stereoselective isomerization into the desired E enol ether. Clean deprotection was achieved providing new 2-amino-4-aryloxybut-3(E)-enoic acids 3.
- Daumas,Vo-Quang,Le Goffic
-
p. 2373 - 2384
(2007/10/02)
-
- Highly Stereocontrolled Total Synthesis of Leukotriene B4, 20-Hydroxyleukotriene B4, Leukotriene B3, and Their Analogues
-
A highly stereocontrolled and practical new method for synthesis of LTB4 (1), 20-OH-LTB4 (2), and LTB3 (3) has been developed, which uses the palladium catalyzed coupling reaction of the vinylborane 5, derived from the C(1)-C(9) fragment 4, with the corresponding C(10)-C(20) fragments 6a-c.The acetylene 4 was synthesized by palladium-copper-catalyzed coupling reaction of (trimethylsilyl)acetylene with the bromide 12, which was prepared from γ-(trimethylsilyl)allylic alcohol (S)-10 by bromination followed by debromosilylation.The alcohol (S)-10 was obtained by the kinetic resolution of the racemate dl-10 using the Sharpless reagent.The vinyl iodides 6a and 6b were prepared from racemic γ-(trimethylsilyl)allylic alcohols dl-17 and dl-28, respectively, by the Sharpless kinetic resolution followed by the reactions taking advantage of the reactivity of vinylsilane moiety, while the segment 6c was prepared by the Sharpless kinetic resolution of racemic γ-iodoallylic alcohol dl-34 followed by protection.By using this method, precursors of the radiolabeled LTB4, and 20-OH-LTB4, i.e., 14,15-didehydro-LTB4 (40) and 14,15-didehydro-20-OH-LTB4 (41), respectively, were also synthesized.Similarly the novel structural analogue of LTB 42-44 were prepared.
- Kobayashi, Yuichi,Shimazaki, Toshiyuki,Taguchi, Hideki,Sato, Fumie
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p. 5324 - 5335
(2007/10/02)
-
- Formation of Optically Active Aryloxyacetaldehyde Cyanohydrin Acetates with the Aid of a Microorganism
-
Microorganisms that hydrolyze the one enantiomer of dl-phenoxyacetaldehyde cyanohydrin acetate were screened, and Bacillus coagulans isolated from soil was found to be the best.This bacterium was applied to the asymmetric hydrolysis of other aryloxyacetaldehyde derivatives to give satisfactory results.The effect of adding dimethyl sulfoxide to the medium is also described.
- Ohta, Hiromichi,Miyamae, Yoshitaka,Tsuchihashi, Gen-ichi
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p. 215 - 222
(2007/10/02)
-
- PROSTANOIDS. V. THE ω-CHAIN FOR 16-ARYLOXYTETRANORPROSTAGLANDINS
-
During hydrostannylation of 4-aryloxy-3-hydroxy-1-butynes and subsequent cleavage of the obtained E-vinylstannates with iodine the corresponding E-1-iodo-3-hydroxy-4-aryloxy-1-butenes were synthesized.
- Tolstikov, G. A.,Miftakhov, M. S.,Danilova, N. A.,Galin, F. Z.
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p. 1624 - 1631
(2007/10/02)
-
- Enzyme-activated oxidative process for coloring hair
-
An enzyme-based oxidative process for coloring hair wherein the hair is exposed to a solution having a pH of about 4 to about 10 and containing hydrogen peroxide, soybean peroxidase enzyme and one or more oxidation dye precursors.
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-
- OXIDATION OF PHENYL CELLOSOLVE.
-
Vapor-phase oxidation of phenyl Cellosolve (tradename for ethylene glycol monophenyl ether) was studied and the optimal conditions for formation of phenoxyacetaldehyde were found. It was shown that the phenoxyacetaldehyde polymer accompanying the main product can be used in the Mannich reaction like the monomer.
- Keiko,Chichkarev,Keiko
-
p. 2847 - 2849
(2007/10/05)
-