- Formal synthesis of brivaracetam: A key to construct the pyrrolidone scaffold using Pd-catalyzed oxidative cyclization and ring-closing metathesis reaction
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A short and efficient synthetic approach for brivaracetam has been accomplished via two different routes which utilize Pd-catalyzed oxidative cyclization and ring-closing metathesis (RCM) as the key reaction. These two routes are novel, simple, scalable and rely on (E)-pent-2-en-1-ol and valeraldehyde as a commercially available starting material to yield brivaracetam with good overall yield.
- Chavan, Subhash P.,Kawale, Sanket A.,Chavan, Prakash N.
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- Cascade Michael addition/cycloketalization of cyclic 1,3-dicarbonyl compounds: Important role of the tethered alcohol of α,β-unsaturated carbonyl compounds on reaction rate and regioselectivity
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Reactions of α,β-unsaturated aldehydes and cyclic 1,3-dicarbonyl compounds proceed primarily by cascade Knoevenagel condensation/six-π-electron electrocyclization (K6EC, formal [3 + 3] cycloaddition), while α,β-unsaturated ketones usually react with cyclic 1,3-dicarbonyl compounds in a 1,4-addition manner. This paper discloses our findings that under acidic conditions, α,β-unsaturated carbonyl compounds (ketones and aldehydes) with a tethered alcohol react with cyclic 1,3-dicarbonyl compounds in a highly regioselective 1,4-addition fashion via in situ generation of a hypothetical α-methylene cyclic oxonium ion as the reactive Michael acceptor. Our studies uncovered the important effect of the tethered alcohol on the reaction rate and/or efficiency and some new mechanistic aspects of the cascade Michael addition/cycloketalization. Finally, the substrate scope was examined, and 43 analogues of penicipyrone and tenuipyrone were prepared in good to excellent yields.
- Yao, Hongliang,Song, Liyan,Liu, Yuan,Tong, Rongbiao
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- Three Ways Aliphatic Aldehydes React with Nonstabilized Azomethine Ylides
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Aliphatic aldehydes readily react with nonstabilized azomethine ylides in one of the three ways to give oxazolidines, pyrrolidines, or Mannich bases, depending on the structure of the starting compound and the reaction conditions. The use of N -(methoxymethyl)- N -[(trimethylsilyl)methyl]benzylamine in DMF provided 5-alkyloxazolidines in 40-97percent yields. On the other hand, three-component reactions of aliphatic aldehydes bearing one α-hydrogen with N -methyl(benzyl)glycine and formaldehyde gives Mannich bases in yields of 47-98percent. A similar reaction of aldehydes bearing branched alkyl groups and two hydrogen atoms at the α-position proceeds as a domino process that gives 3-alkyl-3-formylpyrrolidines in yields of 34-93percent.
- Buev, Evgeny M.,Gorbunova, Evgeniya V.,Moshkin, Vladimir S.,Sosnovskikh, Vyacheslav Y.
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- ODORANTS AND COMPOSITIONS COMPRISING ODORANTS
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The present invention relates to new classes of odorous 3-(2- methylenealkoxy)alkanenitrile derivatives of formula (I) which are useful as fragrance or flavor materials in particular in providing dry, woody, dusty, earthy, and/or patchouli notes together with optional coriander, aldehydic, citrus, mandarin, pear, cinnamon, and/ or petal floral-like notes to perfume, aroma or deodorizing/masking compositions.
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Page/Page column 26
(2021/10/22)
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- Substituted thiophene and benzoquinone and isoxazole compound and its preparation method and application
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The invention relates to the technical field of medicine, and provides substituted tricyclo-quinone compounds and pharmaceutically acceptable salts thereof. The structural general formula of the substituted aromatic tetracyclic compounds is disclosed in the specification. The invention also provides a preparation method of the compounds and application of the compounds in preparation of antifungal drugs.
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Paragraph 0176; 0177
(2017/07/23)
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- Lewis Acid Catalyzed Formal Intramolecular [3 + 3] Cross-Cycloaddition of Cyclopropane 1,1-Diesters for Construction of Benzobicyclo[2.2.2]octane Skeletons
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A novel Lewis acid catalyzed formal intramolecular [3 + 3] cross-cycloaddition (IMCC) of cyclopropane 1,1-diesters has been successfully developed. This supplies an efficient and conceptually new strategy for construction of bridged bicyclo[2.2.2]octane skeletons. This [3 + 3]IMCC could be run up to gram scale and from easily prepared starting materials. This [3 + 3]IMCC, together with our previously reported [3 + 2]IMCC strategy, can afford either the bicyclo[2.2.2]octane or bicyclo[3.2.1]octane skeletons from the similar starting materials by regulating the substituents on vinyl group.
- Ma, Weiwei,Fang, Jie,Ren, Jun,Wang, Zhongwen
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supporting information
p. 4180 - 4183
(2015/09/15)
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- The cinchona primary amine-catalyzed asymmetric epoxidation and hydroperoxidation of α,β-unsaturated carbonyl compounds with hydrogen peroxide
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Using cinchona alkaloid-derived primary amines as catalysts and aqueous hydrogen peroxide as the oxidant, we have developed highly enantioselective Weitz-Scheffer-type epoxidation and hydroperoxidation reactions of α,β-unsaturated carbonyl compounds (up to 99.5:0.5 er). In this article, we present our full studies on this family of reactions, employing acyclic enones, 5-15-membered cyclic enones, and α-branched enals as substrates. In addition to an expanded scope, synthetic applications of the products are presented. We also report detailed mechanistic investigations of the catalytic intermediates, structure-activity relationships of the cinchona amine catalyst, and rationalization of the absolute stereoselectivity by NMR spectroscopic studies and DFT calculations.
- Lifchits, Olga,Mahlau, Manuel,Reisinger, Corinna M.,Lee, Anna,Fares, Christophe,Polyak, Iakov,Gopakumar, Gopinadhanpillai,Thiel, Walter,List, Benjamin
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supporting information
p. 6677 - 6693
(2013/06/05)
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- SPIROINDOLINONE DERIVATIVES
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The present invention relates to spiroindolinone derivatives of the formula and their enantiomers and pharmaceutically acceptable salts and esters thereof wherein R1, R2, R3, R4, R5, R6, R7 and R8, are as herein described.
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Page/Page column 72
(2008/06/13)
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- CONCISE BETA2-AMINO ACID SYNTHESIS VIA ORGANOCATALYTIC AMINOMETHYLATION
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The present invention provides a method for the synthesis of ?2-amino acids. The method also provides methods yielding a-substituted ?-amino aldehydes and ?-substituted γ-amino alcohols. The present method according to this invention allows for increased yield and easier purification using minimal chromatography or crystallization. The methods described herein are based on an aldehyde aminomethylation which involves a Mannich reaction between an aldehyde and a formaldehyde-derived N,O-acetal (iminium precursor) and a catalyst, such as, for example, L-proline or a pyrrolidine. The invention allows for large scale, commercial preparation of ?2-amino acids.
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- Diastereoselective addition of organozinc reagents to 2-alkyl-3- (arylsulfanyl)propanals
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The preparation of compounds incorporating the 3-hydroxy-2-methyl-1-alkyl moiety of high diastereomeric purity is described. Such compounds can serve as potential building blocks for the preparation of several kinds of natural products. Diastereoselective synthesis of two potential pine sawfly pheromone components, one the pure racemic threo-isomer of 3-methylpentadecan-2-ol and the other the racemic erythro-isomer of 3-methyltridecan-2-ol are described. The diastereoselective addition of R2Zn (R=Me, Et and n-Bu) to several 2-alkyl-3-(arylsulfanyl)propanals in the presence of a Lewis acid and CH 2Cl2 as solvent was studied. An excellent diastereomeric ratio (95/5 anti-Cram/Cram) was obtained with 2-[(phenylsulfanyl)methyl] pentanal, 2-[(phenylsulfanyl)methyl]decanal and 2-[(phenylsulfanyl)methyl] dodecanal and Me2Zn in the presence of TiCl4. (a) Lewis acid catalysed dimethylzinc addition; (b) 1. Prot. and oxidation to sulfone, 2. Alkylation; (c) Deprot. and desulfonation; (d) Desulfurisation.
- Larsson, Michael,Galandrin, Elodie,H?gberg, Hans-Erik
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p. 10659 - 10669
(2007/10/03)
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- Substituted hepta-1,6-dien-3-ones with green/fruity odours green/galbanum olfactophore model
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Following an analysis of available SAR data on green/galbanum-smelling molecules, a series of new 2-substituted hepta-1,6-dien-3-ones and their analogues were prepared and their olfactory properties evaluated. The study allowed to select efficient new odourants - potential substitutes for natural galbanum oil - and to generate an olfactophore model for the green/galbanum note.
- Bajgrowicz, Jerzy A.,Berg-Schultz, Katja,Brunner, Gerhard
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p. 2931 - 2946
(2007/10/03)
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- Contrast media synthesized from polyaldehydes
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Microparticles comprising biodegradable polymers, characterized in that they are synthesized from polymerizable aldehydes, which optionally contain additives and/or crosslinkers capable of copolymerization, optionally surfactants or surfactant mixtures, gases and/or highly volatile liquids in free or bound form, coupling agents, optionally biomolecules or macromolecules bound by these coupling agents as well as optionally diagnostically or therapeutically effective components, are suitable as ultrasonic contrast media.
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- SYNTHESIS AND REACTIONS OF SUBSTITUTED ACROLEINS.
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In this work we examined methods for obtaining 2-alkylacroleins and their derivatives that would render these compounds as cheap and readily available products of organic synthesis. Using aldehydes we show that ethylene glycol, glycerin, and pentaerythritol in the presence of acid catalysts react primarily at the carbonyl group. Maximal yields (50-80%) were obtained when using the cation exchanger KU-2 as the acid catalyst, which also simplified the isolation of the desired products. The 2-alkyl-1,3-dioxacyclanes obtained are of particular interest as monomers, comonomers, and intermediate products of organic synthesis.
- Saprygina,Zlot-skii,Rakhmankulov
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p. 862 - 866
(2007/10/02)
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- 15-Deoxy-16-hydroxy-17-methylene prostaglandins of the E and F series
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The invention disclosed herein relates to pharmacologically active prostaglandin derivatives of the E and F series wherein C-16 is substituted with hydroxy and methyl and a double bond is introduced between C-19 and C-20. These compounds are active as bronchodilators, anti-ulcer agents and fertility control agents.
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