- Benzoylation of deactivated compounds of the thiophene and furan series with phenyldichlorocarbenium tetrachloroaluminate
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The reactions of benzotrichloride with methyl and ethyl esters and nitriles of 2-thiophenecarboxylic and 2-furancarboxylic acids, with 2-acetylthiophene, 2-acetylfuran, and 2-thiophenaldehyde in the presence of an excess of anhydrous aluminum chloride hav
- Belen'kii,Gromova,Kolotaev,Krayushkin
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- CO2-Catalyzed oxidation of benzylic and allylic alcohols with DMSO
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CO2-catalyzed transition-metal-free oxidation of alcohols has been achieved. Earlier, several methodologies have been explored for alcohol oxidations based on transition-metal catalysts. However, owing to the cheaper price, easy separation and nontoxicity, transition-metal-free systems are in high demand to the pharmaceutical industries. For this reason, various primary and secondary alcohols have been selectively oxidized to the corresponding carbonyl compounds using CO2 as a catalyst in the presence of different functional groups such as nitrile, nitro, aldehyde, ester, halogen, ether, and so on. At the end, transition-metal-free syntheses of pharmaceuticals have also been achieved. Finally, the role of CO2 has been investigated in detail, and the mechanism is proposed on the basis of experiments and DFT calculations.
- Riemer, Daniel,Mandaviya, Bhavdip,Schilling, Waldemar,G?tz, Anne Charlotte,Kühl, Torben,Finger, Markus,Das, Shoubhik
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p. 3030 - 3034
(2018/04/14)
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- A general approach to intermolecular carbonylation of arene C-H bonds to ketones through catalytic aroyl triflate formation
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The development of metal-catalysed methods to functionalize inert C-H bonds has become a dominant research theme in the past decade as an approach to efficient synthesis. However, the incorporation of carbon monoxide into such reactions to form valuable ketones has to date proved a challenge, despite its potential as a straightforward and green alternative to Friedel-Crafts reactions. Here we describe a new approach to palladium-catalysed C-H bond functionalization in which carbon monoxide is used to drive the generation of high-energy electrophiles. This offers a method to couple the useful features of metal-catalysed C-H functionalization (stable and available reagents) and electrophilic acylations (broad scope and selectivity), and synthesize ketones simply from aryl iodides, CO and arenes. Notably, the reaction proceeds in an intermolecular fashion, without directing groups and at very low palladium-catalyst loadings. Mechanistic studies show that the reaction proceeds through the catalytic build-up of potent aroyl triflate electrophiles.
- Kinney, R. Garrison,Tjutrins, Jevgenijs,Torres, Gerardo M.,Liu, Nina Jiabao,Kulkarni, Omkar,Arndtsen, Bruce A.
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p. 193 - 199
(2018/02/06)
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- COMPOUNDS HAVING MUSCARINIC RECEPTOR ANTAGONIST AND BETA2 ADRENERGIC RECEPTOR AGONIST ACTIVITY
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The present invention relates to compounds acting both as muscarinic receptor antagonists and beta2 adrenergic receptor agonists, to processes for their preparation, to compositions comprising them, to therapeutic uses and combinations with other pharmaceutical active ingredients.
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Page/Page column 135
(2013/02/27)
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- Microwave promoted facile synthesis of methyl and ethyl carboxylates
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Microwave irradiation of carboxylic acids with trialkyl orthoacetate in solvent-free conditions afforded an efficient method for alkylation of carboxylic acids to corresponding alkyl carboxylates.
- Lee, Jong Chan,Song, In-Goul,Park, Jin Young
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p. 2209 - 2213
(2007/10/03)
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- Isomerization of Trimethyl α-Keto Trithioorthocarboxylates into α,α-Bis(methylthio) Thiolcarboxylates. A New Rearrangement of Synthetic Interest
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A study was made of the isomerization reaction of a great variety of trimethyl α-keto trithioorthocarboxylates to α,α-bis(methylthio) thiolcarboxylates, intermediates of high synthetic value for the synthesis of α-arylpropionic acids. The reaction was carried out in methylene chloride in the presence of catalytic amounts of trityl perchlorate or methanesulfonic acid and was complete in 2 h at rt. In most of the investigated cases the result was positive, the yields usually being greater than 90%. Also the reaction mechanism was subjected to an experimental study.
- Degani, Iacopo,Dughera, Stefano,Fochi, Rita,Gazzetto, Sonia
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p. 7228 - 7233
(2007/10/03)
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- Non-prostanoid thromboxane A2 receptor antagonists with a dibenzoxepin ring system. 1
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A series of 11-[[2-[(arylsulfonyl)amino]ethyl]thio]-6,11- dihydrodibenz[b,e]oxepin-2-carboxylic acids and related derivatives were synthesized. The compounds were tested for their antagonizing effects on guinea pig platelet TXA2/PGH2 receptors. Structure-activity relationships are discussed. (±)-11-[[2-[(Styrylsulfonyl)amino]ethyl]thio]-6,11- dihydrodibenz[b,e]oxepin-2-carboxylic acid (41) and (±)-11-[[2- [(phenylsulfonyl)amino]ethyl]thio]-6,11-dihydrodibenz[b,e]thiepin-2- carboxylic acid (4af) were the most promising compounds with K(i) values of 6.5 ± 0.29 and 3.7 ± 0.31 nM, respectively, for the TXA2/PGH2 receptor. These compounds also significantly inhibited U-46619-induced guinea pig platelet aggregation ex vivo (10 mg/kg po). Compound 41 was resolved into its optically active form. The (-)-isomer was 60-fold more potent than the (+)- isomer in the TXA2/PGH2 receptor binding assay. Some compounds tested in this study showed both TXA2/PGH2 receptor antagonizing and TXA2 synthase inhibitory effects.
- Ohshima,Takami,Sato,Obase,Miki,Ishii,Karasawa,Kubo
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p. 3394 - 3402
(2007/10/02)
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- Correlation of Carbon-13 Substituent-Induced Chemical Shifts: meta- and para-Substituted Methyl Benzoates
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Carbon-13 NMR spectra are reported for 69 substituted methyl benzoates in deuteriochloroform or in its mixture with dimethyl sulphoxide-d6.The substituent-induced chemical shifts (SCS) of the CO carbon correlate poorly with dual substituent parameters (DSP) in all possible modifications, and for meta derivatives in particular this correlation is both overparameterized and imprecise.A much better correlation was obtained with parameters (designated Bm, Bp and Cp) derived previously by principal component analysis (PCA) from a larger set.The SCS of the CH3 carbon correlate very well with the original simple Hammett equation, and no DSP treatment is needed.The clustering of substituents is not consequential in such a large set.KEY WORDS Methyl benzoates 13C NMR Substituent effects
- Budesinsky, Milos,Exner, Otto
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p. 585 - 591
(2007/10/02)
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- Deactivation of Triplet Phenyl Alkyl Ketones by Conjugatively Electron-Withdrawing Substituents
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Para-cyano, -carbomethoxy, and -acyl substituents decrease the triplet reactivity of valerophenone (γ-hydrogen abstraction), whereas comparable meta substituents increase reactivity.Spectroscopic results are presented which indicate that para-(-R) substituents lower ?,?* triplet energies so much more than n,?* energies that the lowest triplets become largely ?,?* in nature.Meta-(-R) substituents do not stabilize ?,?* triplets enough to invert triplet levels.Both substitution patterns support a largely 1,4-biradical structure for the lowest ?,?* triplet of acylbenzenes.Ortho substituents show the usual steric anomalies: ortho cyano enhances valerophenone triplet reactivity by stabilizing the n,?* triplet; ortho carbomethoxy deactivates valerophenone by stabilizing the ?,?* triplet but not the n,?.*
- Wagner, Peter J.,Siebert, Elizabeth J.
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p. 7329 - 7335
(2007/10/02)
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- Ketone derivatives
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o-Hydroxybenzophenones and derivatives thereof are described together with a process for their production. The compounds have anti-allergy activity and are characterized by the presence of an alkyl substituent on the hydroxyphenyl ring.
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