- PHOTOCHEMISTRY OF 1,3-DIMETHYLURACIL. A NOVEL PHOTOCHEMICAL RING-OPENING LEADING TO AN ENAMINE
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Besides known reduction and solvent addition products, the photolysis of 1,3-dimethyluracil in methanol resulted in formation of the enamine 2-methoxycarbonyl-N-methyl-3-methylaminopropenamide (5) via a novel ring-opening reaction.A mechanism for the formation of 5 is suggested and its structure was confirmed by an independent synthesis.
- Arys, Maria,Christensen, Torben B.,Eriksen, Jens
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- Ozonolysis of α-angelica lactone: a renewable route to malonates
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Industrially relevant intermediates such as malonic acid, malonates and 3-oxopropionates can be easily accessed by ozonolysis of α-angelica lactone, derived from the platform chemical levulinic acid. The roles of the solvent and of the quenching conditions are of key importance for the outcome of the reaction.
- Dell’Acqua, Andrea,Wille, Lukas,Stadler, Bernhard M.,Tin, Sergey,de Vries, Johannes G.
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supporting information
p. 10524 - 10527
(2021/10/19)
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- Method for preparing diacid diester compound under catalysis of deep eutectic solvent
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The invention belongs to the technical field of organic synthesis, and discloses a method for preparing a diacid diester compound through catalysis of a deep eutectic solvent, wherein the deep eutectic solvent takes ammonium salt and ferric salt as hydrogen acceptors, takes p-toluenesulfonic acid as a hydrogen donor, takes diacid or anhydride of the diacid and an alcohol compound as raw materials, and adopts a one-pot method to prepare the diacid diester compound; and under the catalysis of the deep eutectic solvent, the esterification reaction is performed to generate the diester product. The selected deep eutectic solvent has characteristics of environmental protection, easy preparation, cheap components and easy recovery; the preparation method has characteristics of simple operation, simple separation, no water-carrying agent, repeated use of the deep eutectic solvent, and high diester yield.
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Paragraph 0035-0038
(2021/05/19)
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- A Br?nsted acidic, ionic liquid containing, heteropolyacid functionalized polysiloxane network as a highly selective catalyst for the esterification of dicarboxylic acids
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A Br?nsted acidic, ionic liquid containing, heteropolyanion functionalized polysiloxane network was formed by self-condensation of dodecatungstophosphoric acid and a zwitterionic organosilane precursor containing both imidazolinium and sulfonate groups. The resulting hybrid material POS-HPA-IL was investigated as a catalyst for the selective esterification of dicarboxylic acids.
- Rajabi, Fatemeh,Wilhelm, Christian,Thiel, Werner R.
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supporting information
p. 4438 - 4444
(2020/08/10)
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- Enantioselective α-Amination of Acyclic 1,3-Dicarbonyls Catalyzed by N-Heterocyclic Carbene
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Herein, we describe a method for the catalytic enantioselective α-amination of α-substituted acyclic 1,3-ketoamides and 1,3-amidoesters that affords the products possessing N-substituted quaternary stereocenters with a chiral N-heterocyclic carbene (NHC). The reaction is based on the utilization of an intrinsic Br?nsted base characteristic of NHC that enables the catalytic formation of a chiral ion pair comprising the enolate and the azolium ion. A series of challenging open-chain α-substituted 1,3-dicarbonyls are aminated via this method with ee's of ≤99%.
- Santra, Surojit,Maji, Ujjwal,Guin, Joyram
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supporting information
p. 468 - 473
(2020/02/04)
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- Development of catalytic deacylative alkylations (DaA) of 3-acyl-2-oxindoles: total synthesis of meso-chimonanthine and related alkaloids
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We present an effective deacylative alkylation strategy for the construction of a variety of 2-oxindoles bearing an all-carbon quaternary center at the pseudobenzylic position. A wide variety of products with quaternary centers could be accessed by employing simple Pd(0) catalysis under mild reaction conditions. Importantly, the same strategy works equally well for the dimeric 2-oxindole system, furnishing products with a vicinal quaternary center in favour of meso-isomer as the major product. Eventual application to the total syntheses of meso-chimonanthine and meso-folicanthine very well demonstrates the synthetic potential of this strategy.
- Kumar, Nivesh,Das, Mrinal Kanti,Ghosh, Santanu,Bisai, Alakesh
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supporting information
p. 2170 - 2173
(2017/02/19)
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- Synthesis of 2-oxindoles via 'transition-metal-free' intramolecular dehydrogenative coupling (IDC) of sp2 C-H and sp3 C-H bonds
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The synthesis of a variety of 2-oxindoles bearing an all-carbon quaternary center at the pseudo benzylic position has been achieved via a 'transition-metal-free' intramolecular dehydrogenative coupling (IDC). The construction of 2-oxindole moieties was carried out through formation of carbon-carbon bonds using KOt-Bu-catalyzed one pot C-alkylation of β-N-arylamido esters with alkyl halides followed by a dehydrogenative coupling. Experimental evidences indicated toward a radical-mediated path for this reaction.
- Kumar, Nivesh,Ghosh, Santanu,Bhunia, Subhajit,Bisai, Alakesh
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supporting information
p. 1153 - 1169
(2016/07/06)
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- Optimizing the efficiency of antioxidants in emulsions by lipophilization: Tuning interfacial concentrations
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Optimization of the efficiency of antioxidants, AOs, in lipid-based emulsions via chemical modifications of their reactive moieties is not always possible because of the inherent experimental difficulties and because of the regulatory status of AOs. Esterification of hydrophilic AOs may be a practical, convenient, alternative approach. Here we employed a series of caffeic acid derivatives bearing the same reactive moiety but of different hydrophobicity (alkyl chain lengths of 1 to 16 carbon atoms) to investigate the effects of hydrophobicity on the oxidative stability of stripped corn oil-in-water emulsions. AO efficiency was determined by monitoring the production of primary oxidation products (conjugated dienes) with time and a non-linear, parabolic-like, variation of their efficiency with the number of C atoms in their alkyl chain, with a maximum at the C8 derivative, found. To rationalize the results, we also determined the distribution of the AOs between the oil, interfacial and aqueous regions of the same emulsions by employing a recently developed kinetic method that provides the partition constants of the AO between the oil-interfacial, PIO, and water-interfacial, PIW, regions of the intact emulsions. Values of both PIO and PIW range between 180-2000, suggesting that the transfer of the AOs to the interfacial region is spontaneous. The results indicate that the variations of both the percentage of AO in the interfacial region, % AOI, of the emulsions and the AO efficiency with the number of C atoms in the AO alkyl chain parallel each other with a maxima at the C8 derivative. The results illustrate an effective and convenient way to control lipid oxidation by modulation of the hydrophobicity (HLB) of the AOs. An increase in the alkyl chain length of the AOs promote their incorporation into the interfacial region of emulsions but only up to a critical chain length, after which a further increase makes their efficiency decrease as a consequence of the decrease in their % AOI.
- Costa, Marlene,Losada-Barreiro, Sonia,Paiva-Martins, Fátima,Bravo-Díaz, Carlos
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p. 91483 - 91493
(2016/10/09)
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- Direct synthesis of polysubstituted 2-aminothiophenes by Cu(ii)-catalyzed addition/oxidative cyclization of alkynoates with thioamides
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A facile and direct synthetic method was developed for the construction of structurally important 2-aminothiophenes in moderate to excellent yields (up to 91%), via Cu(ii)-catalyzed addition/oxidative cyclization of readily available thioamides with alkynoates under an air atmosphere. This journal is
- Ge, Li-Shi,Wang, Zheng-Lin,An, Xing-Lan,Luo, Xiaoyan,Deng, Wei-Ping
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supporting information
p. 8473 - 8479
(2014/12/10)
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- Synthesis and antitumor activity of feruloyl and caffeoyl derivatives This paper is dedicated to Prof. Wei-xiao Hu for his lifelong commitment to mentoring graduate students
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We developed two efficient protocols for the synthesis of feruloyl and caffeoyl derivatives from commercial vanillin and veratraldehyde. Pharmacological activities were assessed against a panel of human cancer cell lines in vitro. Most synthesized compounds demonstrated attractive cytotoxicity. Several new compounds demonstrated significant antiproliferative and cytotoxic activities against HeLa and Bewo tumor cell lines. In particular, 5-nitro caffeic adamantyl ester showed broad spectrum of tumor inhibition in 10 cell lines, and reduced tumor weight by 36.7% in vivo when administered at a dose of 40 mg kg-1.
- Chen, Hui-Zhen,Chen, You-Bao,Lv, Ya-Ping,Zeng, Fang,Zhang, Juan,Zhou, Yong-Lie,Li, Han-Bing,Chen, Li-Fei,Zhou, Bin-Jie,Gao, Jian-Rong,Xia, Chun-Nian
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supporting information
p. 4367 - 4371
(2015/02/06)
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- DDQ-mediated direct Intramolecular-Dehydrogenative-Coupling (IDC): Expeditious approach to the tetracyclic core of ergot alkaloids
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An efficient route to 2-oxindoles bearing an all-carbon quaternary center at the pseudobenzylic position has been developed via a DDQ-mediated Intramolecular-Dehydrogenative-Coupling (IDC). The methodology involves a one-pot C-alkylation of β-N-arylamido esters (7) concomitant with dehydrogenative-coupling in the presence of stoichiometric amount of DDQ. A tentative mechanistic route has been proposed for the oxidative coupling. The methodology provides a two-step entry to the ergoline structure of ergot alkaloids.
- Bhunia, Subhajit,Ghosh, Santanu,Dey, Dhananjay,Bisai, Alakesh
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supporting information
p. 2426 - 2429
(2013/06/27)
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- Intramolecular dehydrogenative coupling of sp2 C-H and sp 3 C-H bonds: An expeditious route to 2-oxindoles
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An intramolecular-dehydrogenative-coupling (IDC) using "transition- metal-free" oxidation conditions has been achieved to synthesize a variety of 2-oxindoles bearing an all-carbon quaternary stereogenic center at the benzylic position. The methodology involves a one-pot C-alkylation of β-N-arylamido esters (3, 6) with alkyl halides using potassium tert-butoxide concomitant with a dehydrogenative coupling. A radical-mediated pathway has been tentatively proposed for the oxidative process.
- Ghosh, Santanu,De, Subhadip,Kakde, Badrinath N.,Bhunia, Subhajit,Adhikary, Amit,Bisai, Alakesh
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supporting information
p. 5864 - 5867
(2013/02/22)
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- One-pot preparation of phenylpropanoid esters co-catalyzed by boric acid and piperidine
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Phenylpropanoid esters, especially those with hydroxyl and/or methoxy groups on the benzene ring, are important medicinal chemicals or intermediates. They are usually prepared by esterification of their corresponding substituted cinnamic acids with various alcohols. However, the esterification procedures often suffer from environmentally hazardous problems when sulfuric acid is used as a catalyst or suffer from unsatisfactory yields and expensive raw material when enzyme is applied as a catalyst. In this paper, a convenient one-pot process for preparing various phenylpropanoid esters from substituted benzaldehydes bearing hydroxyl and/or methoxyl groups has been developed. The alcohols react first with malonic acid catalyzed by boric acid to form monomalonate, then without separation, let the resultant mixture immediately react with the injected various substituted benzaldehydes in the presence of piperidine to afford the desired esters with moderate to good yields. Springer Science+Business Media B.V. 2011.
- Wang, Huan,Wei, Qing-Yi,Jiang, Hong,Jiang, Zhen-Hua
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experimental part
p. 207 - 213
(2012/05/20)
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- Practical large scale synthesis of half-esters of malonic acid
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A practical large-scale synthesis of monomethyl malonate and monoethyl malonate, which are among the most commonly applied half-esters in organic synthesis, is described, applying the highly efficient selective monohydrolysis of symmetric diesters we reported before. The optimal conditions with regard to the type of base, equivalent, co-solvents, and the reaction time have been examined for large-scale reactions. Monomethyl malonate and monoethyl malonate were obtained in high yields with near 100% purity within only half a day. The conditions of this selective monohydrolysis reaction are environmentally benign and straightforward, as it requires only water, a small proportion of a volatile co-solvent, and inexpensive reagents, and produces no hazardous by-products, and therefore the synthetic utility of this reaction in process chemistry is expected.
- Niwayama, Satomi,Cho, Hanjoung
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scheme or table
p. 508 - 510
(2009/12/09)
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- Synthesis of trans-caffeate analogues and their bioactivities against HIV-1 integrase and cancer cell lines
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Forty caffeate analogues were synthesized via a convenient method starting from vanillin with moderate to good yields. The testing of biological activity of these compounds against HIV-1 integrase indicates that four compounds: bornyl caffeate, bornyl 2-nitrocaffeate, 5-nitrocaffeic acid and 5-nitrocaffeic acid phenethyl ester (5-nitroCAPE) possess a good HIV integrase inhibitory activity, IC50 19.9, 26.8, 25.0 and 13.5 μM, respectively. Twelve caffeate analogues were tested by MTT assay on growth of human hepatocellular carcinoma BEL-7404, human breast MCF-7 adenocarcinoma, human lung A549 adenocarcinoma and human gastric cancer BCG823 cell lines, respectively. And the best result is IC50 5.5 μM for CAPE against BEL-7404.
- Xia, Chun-nian,Li, Hai-bo,liu, Feng,Hu, Wei-xiao
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supporting information; experimental part
p. 6553 - 6557
(2009/09/06)
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- SYNTHESIS OF HALF ESTERS
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A method for hydrolyzing an ester is provided. In accordance with the method, a compound A is provided which has first and second ester moieties. The compound is reacted in a liquid medium with a base having the formula MaXb,such that the first ester moiety is converted to a carboxyl moiety and the second ester moiety remains, wherein the ratio [Xk-]:[A] in the liquid medium is no greater than 1.6, and wherein k > 0.
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Page/Page column 16-17
(2009/01/24)
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- A quantitative structure-reactivity relationship in decarboxylative Claisen rearrangement reactions of allylic tosylmalonate esters
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First-order rate constants have been determined for the decarboxylative Claisen rearrangement reactions at 293 K of substituted methyl (E)-3-phenyl-2-propenyl 2-tosylmalonate esters, which show a linear free-energy relationship indicative of the development of positive charge on the benzylic position in the sigmatropic rearrangement transition-state. The Royal Society of Chemistry.
- Craig, Donald,Slavov, Nikolay K.
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supporting information; experimental part
p. 6054 - 6056
(2009/05/06)
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- Highly efficient selective monohydrolysis of dialkyl malonates and their derivatives
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The highly efficient selective monohydrolysis of symmetric diesters has been applied to monohydrolysis of several dialkyl malonates and their derivatives. The best conditions apply 0.8-1.2 equiv of aqueous KOH with a co-solvent, THF or acetonitrile, at 0 °C. The procedure is highly practical, yielding the corresponding half-esters in high yields in a straightforward manner, without inducing decarboxylation. It was found that the selectivity tends to become higher with increased hydrophobicity.
- Niwayama, Satomi,Cho, Hanjoung,Lin, Chunlei
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p. 4434 - 4436
(2008/12/21)
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- Selective monoesterification of malonic acid catalyzed by boric acid
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Boric acid catalyzes the monoesterification of malonic acid, likely through a chelation mechanism that is not available to the monoester product. Under more forcing conditions, diesters form to some extent, but conditions can be optimized to favour the monoester product (56?80%). With the easily handled solid acid catalyst, these reactions can be run with excess alcohol as solvent or with stoichiometric amounts of alcohol in acetonitrile with moderate heating. CSIRO 2007.
- Levonis, Stephan M.,Bornaghi, Laurent F.,Houston, Todd A.
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p. 821 - 823
(2008/03/12)
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- One-pot preparation of caffeic acid esters from 3,4-dihydroxybenzaldehyde
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A convenient one-pot process for preparing various esters of caffeic acid from 3,4-dihydroxybenzaldehyde has been developed. The alcohols or phenols react with Meldrum's acid to form malonic acid mono-esters, which, without separating, immediately react with 3,4-dihydroxybenzaldehyde to afford the desired esters in good yield. The 1H NMR data and X-ray diffraction analyses indicate that these α,β-unsaturated esters are in trans (E) form in accord with natural esters.
- Hu, Wei-Xiao,Xia, Chun-Nian,Wang, Guo-Hong,Zhou, Wei
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p. 586 - 588
(2007/10/03)
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- Decarboxylative Claisen rearrangement reactions of allylic tosylmalonate esters
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(Chemical Equation Presented) Two different combinations of silylating agent and base are used for one-pot [3,3]-sigmatropic rearrangement- decarboxylation reactions of tosylmalonic mono(allylic) esters under mild conditions, providing the products of formal regiospecific allylation of methyl tosylacetate at the more substituted allylic terminus.
- Craig, Donald,Grellepois, Fabienne
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p. 463 - 465
(2007/10/03)
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- Synthesis of bone-targeted oestrogenic compounds for the inhibition of bone resorption
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Syntheses have been realised for several members of a new class of potential bone resorption inhibitors consisting of steroidal oestrogenic compounds linked at the 17 position to a geminal bis(phosphonic acid) moiety through an ester linkage. The approach used has the potential to allow other biologically active compounds to be coupled to the geminal bisphosphonate unit.
- Bulman Page, Philip C,Moore, Jonathan P.G,Mansfield, Ian,McKenzie, Michael J,Bowler, Wayne B,Gallagher, James A
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p. 1837 - 1847
(2007/10/03)
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- Replacement of glycine with dicarbonyl and related moieties in analogues of the C-terminal pentapeptide of cholecystokinin: CCK2 agonists displaying a novel binding mode
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Recent advances in the field of cholecystokinin have indicated the possible occurrence of multiple affinity states of the CCK2 receptor. Besides, numerous pharmacological experiments performed 'in vitro' and 'in vivo' support the eventuality of different pharmacological profiles associated to CCK2 ligands. Indeed, some agonists are essentially anxiogenic and uneffective in memory tests, whereas others are not anxiogenic and appear as able to reinforce memory. The reference compound for the latter profile is the CCK-8 analogue BC 264 (Boc-Tyr(SO3H)-gNle-mGly-Trp-(NMe)Nle-Asp-Phe-NH2). However, although tetrapeptide ligands based on CCK-4 (Trp-Met-Asp-Phe-NH2) are known to possess sufficient structural features for CCK2 recognition, none shares the properties of BC 264. Hence we have developed new short peptidic or pseud-opeptidic derivatives containing the C-terminal tetrapeptide of BC 264. Our results indicate that some compounds characterized by the presence of two carbonyl groups at the N-terminus, as in 2b (HO2C-CH2-CONH-Trp-(NMe)Nle-Asp-Phe-NH2), are likely to show a BC 264-like profile, bind to the CCK2 receptor in a specific way, and display remarkable affinities (2b: 0.28 nM on guinea-pig cortex membrane preparations). This original binding mode is discussed and further enlightened by NMR and molecular modeling studies.
- Bellier,Million,DaNascimento,Meudal,Kellou,Maigret,Garbay
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p. 3614 - 3623
(2007/10/03)
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- Process for the preparation of roquinimex
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The present invention is an improved process to prepare roquinimex (IV) which comprises: (1) contacting N-methyl-N-phenyl-α-carbomethoxyamide (V) with from about one to about two equivalents of base and (2) contacting the mixture of step (1) with N-methylisatoic anhydride (I).
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- Heterocyclic compounds for the treatment of CNS and cardiovascular disorders
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Novel aromatic bicyclic amines of formula (I) STR1 are useful in treating central nervous system disorders and cardiac arrhythmias and cardiac fibrillation.
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- Enzymatic Preparation of Alkanedicarboxylic Acid Monoesters
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Hydrolysis of alkanedicarboxylic acid dimethyl esters using esterase from Pseudomonas putida MR-2068 gave exclusively pure monoesters.Hydrolytic activities were dependent on the carbon chain length of the substrates.This esterase also catalyzed enantio- and regio-selective hydrolysis of α-methylalkanedicarboxylic acid dimethyl esters.
- Ozaki, Eiji,Uragaki, Toshitaka,Sakashita, Keiichi,Sakimae, Akihiro
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p. 539 - 540
(2007/10/03)
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- Method of manufacturing substituted monoamides of dicarboxylic-acid monoalkyl esters
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A method of preparing a compound of the formula STR1 in which R1 is CH3 or C2 H5, n is 0 to 4, m is 1 to 3, R2 is H, --COOR1, alkyl or aryl, and R3 and R4 each independently is H, alkyl or aryl, which comprises reacting an alkyl ester of a dicarboxylic acid of the formula R1 OOC--CR3 R4 --COOR1 with a nitrile of the formula N C--(CH2)m R2 and with hydrogen in the presence of a hydrogenation catalyst.
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- Enzyme-Catalyzed Hydrolyses of E/Z-Diastereotopic and E/Z-Diastereomeric Esters. Affect on Selectivity by Reaction Media
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PLE-catalyzed hydrolyses of different types of E/Z-diastereotopic diesters and E/Z-diastereomeric monoesters have been studied.Arylidenepropanedioic diesters are specifically hydrolyzed to the Z-half esters, whereas the de values for dialkylated methylene propanedioic diesters range between 33 and 79percent (Z).D values for the hydrolyses of the 3-methyleneazetidin-2-ones in detergent-buffer systems depend on the size of the substituent in the α-position.Diastereoselectivity of these substrates is affected by addition of the cosolvents acetonitrile and methanol.
- Schirmeister, Tanja,Otto, Hans-Hartwig
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p. 4819 - 4822
(2007/10/02)
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- REACTION OF TRIMETHYLSILYL DERIVATIVES WITH MELDRUM'S ACID : A NEW AND EASY MONOFUNCTIONALIZATION OF MALONIC ACID
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Treament of Meldrum's acid with silylated derivatives (amines, lactams or alcohols) yields very easily monofunctionalized malonic silyl esters.Hydrolysis of these silyl esters leads to the corresponding monoacids with a very good yield.
- Rigo, B.,Fasseur, D.,Cauliez, P.,Couturier, D.
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p. 3073 - 3076
(2007/10/02)
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- REMOTE SUBSTITUENT EFFECTS IN MICROBIAL REDUCTIONS OF 3-KETOGLUTARATE AND 3-KETOADIPATE ESTERS
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The enantioselectivity of yeast mediated reductions of prochiral 3-ketoglutarate and 3-ketoadipate esters to the corresponding 3-hydroxyesters can be influenced by simple differences in the ester groups.
- Brooks, Dee W.,Lee, Nola Castro de,Peevey, Richard
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p. 4623 - 4626
(2007/10/02)
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- AN EASY SYNTHESIS OF MONOMETHYL MALONATE DERIVATIVES
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Monomethyl malonates (IIIa-c and Va) were synthesized from Meldrum's acid (Ia) by treating with an excess of diazomethane in the corresponding alcohols and piperidine, respectively, in quantitative yields.In a similar manner, 5-p-chlorobenzyl Meldrum's acid (Ib) afforded the corresponding monomethyl malonate derivatives (IIIe, f, and Vb).The mechanism proposed for this reaction is described.KEYWORDS - Meldrum's acid; monomethyl malonate; half ester; ketene ester; 4,6-dioxo-1,3-dioxane
- Matoba, Katsuhide,Yamazaki, Takao
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p. 2955 - 2956
(2007/10/02)
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