- Unusual tandem sequence of oxa Diels-Alder reaction, retro Diels-Alder reaction, and oxa 6π-electrocyclic ring opening in the reaction of 6-amino-4-(4-methoxyphenyl)-2H-pyran-2-ones with benzaldehydes
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The oxa Diels-Alder reaction of 6-amino-4-(4-methoxyphenyl)-2H-pyran-2-ones with benzaldehydes took an unusual path whereby a tandem sequence of the oxa Diels-Alder reaction, retro Diels-Alder reaction, and 6π-electrocyclic ring opening of the pyran yielded 3-(4-methoxyphenyl)-5-phenyl-1-(piperidin-1-yl/pyrrolidin-1-yl)penta-2,4-dien-1-ones. The reaction took place in boiling toluene with a series of substituted benzaldehydes. An electron-donating group on benzaldehyde retarded the reaction, while an electron-withdrawing group favoured it, thus indicating the normal electron demand pathway. This journal is
- Khatri, Adil I.,Samant, Shriniwas D.
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- Biocompatible natural sugar-based surfactant assisted oxidation of citric acid by MnO4- in absence and presence of SDS
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Crocin, a natural carotenoid with antioxidant properties, was used in the present investigation as a surfactant in the citric acid-MnO4- redox system for the first time. A conventional UV-Visible spectroscopic technique was used to determine the reaction rate with and without crocin. The reaction follows first-order kinetics with respect to [citric acid] under pseudo-first conditions. Crocin was found to catalyze the redox reaction, which was rationalized in terms of the solubilization and/or incorporation of reactants into the crocin aggregates. The micellar catalysis was explained using Menger-Portony pseudo-phase model modified by Bunton et al. The various parameters associated with the micellar catalysis and activation parameters were determined and discussed. Sodium dodecyl sulphate (SDS) inhibits citric acid oxidation. A mixture of non-ionic and anionic surfactant (crocin + SDS) also shows the inhibitory effect rather than catalytic effect. In the mix micellization, the SDS characters and electrostatic repulsion, dominate over the solubilization of reactants in to the Stern layer. On the basis of the observed results, probable mechanisms and reaction sites were proposed.
- Khan, Zaheer,Al-Thabaiti, Shaeel Ahmad,Malik, Maqsood Ahmad
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- Effect of metal ions on acetone dicarboxylic acid catalyzed peroxomonosulphate reactions
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The oxidation of Fe(III), Ni(II) and Co(II) citrates by peroxomonosulphate (PMS) in the pH range 3.0-6.0 follows autocatalysis mechanism. The acetone dicarboxylic acid (ADC), the oxidative decarboxylation product from citrate, is found to catalyze the reaction. The added metal ions switch the reaction from the ADC catalyzed decomposition of PMS to the oxidation of citrates. Based on the results from alcohol quenching, a mechanism involving oxygen atom transfer is proposed.
- Ragukumar,Andal,Murugavelu,Lavanya,Ramachandran
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- Organic Substrates Producing a Dual-Frequency Belousov-Zhabotinskii Oscillating Reaction
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Four organic substrates, acetoacetic acid methyl ester, 4-chloroacetoacetic acid ethyl ester, acetonedicarboxylic acid diethyl ester, and N-methylacetoacetamide, have been found to generate dual-frequency oscillations in the Belousov-Zhabotinskii type reaction system.
- Tsukada, Masao
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Read Online
- Synthetic method of non-steroidal antiinflammatory drug pain killing
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The invention discloses a synthesis method of non-steroidal anti-inflammatory drug tolmetin. The methodcomprises the following steps: sequentially preparing a sulfuric acid-containing acetonedicarboxylic acid crude product, 2-(2-acetoxy)-1-methyl-1H-pyrrole-3-formic acid and 2-(2-alkyl acetate)-1-methyl-1H-pyrrole-3-formic acid by taking citric acid or citric acid monohydrate as a raw material; and carrying out decarboxylation, acylation, hydrolysis and acidification to obtain tolmetin. The synthetic method provided by the invention overcomes the defect that the existing tolmetin preparation process depends on N-methylpyrrole, and is a low-cost, low-pollution and high-yield synthetic method of non-steroidal anti-inflammatory drug tolmetin.
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Paragraph 0041-0043; 0055-0057; 0068-0070; 0081-0083; 0094--
(2021/04/17)
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- Synthesis and antitumor potential of new 7-halocoumarin-4-acetic acid derivatives
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Compounds having their chemical structure based on coumarin framework have enticed much research concern not only because of the variance structural characteristic but also the pluralism of the bioactivities. In this report, four derivatives of 7-halo-4-coumarinylacetic acid referred to as RY1-RY4 were synthesized, and their chemical backbones were confirmed via the employed spectrophotometers. The pharmacokinetic profiles of the synthesized halocoumarins were inspected in silico using a free online software named the pre-ADMET program. The potential of the synthesized halocoumarins as antitumor applicants was evaluated utilizing 5-fluorouracil as a reference drug and the well-authenticated protocol based on the MTT as a visible indicator against eight standard tumor-cell lines. The outcomes acquired from this assessment indicated that the synthesized halocoumarins, except RY1, have less impact as antitumor agents comparing with the standard drug. Also, the halocoumarins revealed roughly the same fashion of activity versus the test cell lines with the greatest inhibitory influence reported against MCF-7 and HeLa. From the calculated pharmacokinetic data and outcomes exhibited from antitumor assessment, the authors concluded that the synthesized halocoumarins, particularly RY1, offered potential applicants as antitumor agents with broad-ranged activity. Besides, the compounds RY1 and RY2 may provide highly valuable scaffolds for synthesizing agents with a powerful antitumor activity versus the breast and cervical cancer phenotypes.
- Mustafa, Yasser Fakri,Khalil, Raghad Riyadh,Mohammed, Eman Tareq
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p. 3711 - 3716
(2021/07/10)
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- Deciphering the Biosynthetic Mechanism of Pelletierine in Lycopodium Alkaloid Biosynthesis
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Pelletierine, a proposed building block of Lycopodium alkaloids (LAs), was demonstrated to be synthesized via the non-enzymatic Mannich-like condensation of Δ1-piperideine and 3-oxoglutaric acid produced by two new type III PKSs (HsPKS4 and PcPKS1) characterized from Huperzia serrata and Phlegmariurus cryptomerianus, respectively. The findings provide new insights for further understanding the biosynthesis of LAs such as huperzine A.
- Abe, Ikuro,Ding, Ning,Hnin, Saw Yu Yu,Jiang, Fang-Fang,Li, Jun,Liu, Xiao,Morita, Hiroyuki,Qi, Bo-Wen,Shi, She-Po,Tu, Peng-Fei,Wang, Juan,Wang, Xiao-Hui,Zhang, Ze-Kun
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- Method for preparing silicon compounds
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The invention provides a method for preparing silicon compounds, and belongs to the field of chemical synthesis. The method for preparing the silicon compounds comprises the following processes that citric acid is used as a raw material for performing oxidative decarboxylation to obtain a compound 1,3-acetone dicarboxylic acid; esterification reaction is carried out to obtain a compound 1,3-acetone dicarboxylic acid dimethyl ester; catalytic hydrogenation reduction is carried out to obtain a compound 3-hydroxyglutaric acid dimethyl ester; etherification reaction is carried out to obtain a compound3-tertiary butyl dimethyl siloxy dimethyl glutarate; saponification, dehydration and purification are carried out to obtain 3-tert-butyl-dimethylsiloxyglutaric anhydride; and a catalyst for catalytic hydrogenation is Cu/ZnO/Al2O3 prepared by a precipitation reduction method. According to the method for preparing the silicon compounds, the catalyst for catalytic hydrogenation is optimized, so that in the hydrogenation reduction reaction, the hydrogenation activity of a Cu catalyst is significantly improved, the selectivity is increased, and the generation of by-products is reduced; and theproduct yield and purity are significantly improved by recrystallization with a mixed solvent.
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Paragraph 0079; 0081; 0082; 0083; 0084; 0085
(2019/11/14)
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- Synthetic method for drug intermediate acetonedicarboxylic acid
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The invention discloses a synthetic method for the drug intermediate acetonedicarboxylic acid. The synthetic method comprises the following steps: adding 2-methoxypropane-1,3-dicarboxylic acid and a sodium nitrate solution into a reaction vessel, increasing the temperature of the obtainded solution, adding lead tetraacetate in batches, controlling a stirring speed and continuing a reaction; and then adding zinc oxalate powder, continuing the reaction, carrying out cooling, carrying out washing with a potassium chloride solution, carrying out washing with a diphenyl ether solution, then carrying out recrystallization in a diethylene glycol solution, and carrying out dehydration with a dehydrating agent so as to obtain the finished acetonedicarboxylic acid.
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Paragraph 0011; 0014-0017; 0018-0021; 0022-0025
(2018/07/30)
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- Preparation method for anticholinergic drug intermediate
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The invention discloses a preparation method for an anticholinergic drug intermediate. Acetone-dicarboxylic acid is a common intermediate for synthesizing medicines, and has a very high application value in organic synthesis. The preparation method comprises the following steps: using citric acid monohydrate as a starting raw material, using concentrated sulfuric acid as a dehydrating agent, and adding a suitable amount of a water absorbent. The method is capable of saving resources, and saving cost, stable in product quality and high in yield, and suitable for large-scale stable industrial production.
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Paragraph 0016; 0017; 0018; 0019; 0020; 0021; 0022; 0023
(2019/01/08)
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- Method for synthesizing atropine drug intermediate acetonedicarboxylic acid
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A method for synthesizing an atropine drug intermediate acetonedicarboxylic acid includes the following steps that 2.8 mol of hypochlorous phenyl ester solution and 600 ml of sodium chloride solution are added into a reaction container provided with a stirrer, a thermometer and a dropping funnel, the solution temperature is reduced to 3-6 DEG C, stirring speed is controlled to be 110-160 rpm, 3.2-3.6 mol of 3-amino-3-amide-glutaric acid, 1.6 mol of alumina and 300 ml of dimethylbenzene are slowly added in batches, addition time is controlled to be 90-120 min, the solution temperature is slowly raised to 50-55 DEG C, reaction is conducted for 100-150 min, the solution temperature is reduced to 2-5 DEG C, standing is conducted for 3-5 h, 1200 ml of potassium bromide solution is added in the stirring state, white solid is separated out, subjected to suction filtration, washed with a saline solution and cyclohexanone, dehydrated with a dehydration agent and recrystallized in N-methylformamide, and crystal of acetonedicarboxylic acid is obtained.
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Paragraph 0014; 0015
(2016/10/31)
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- Regiospecific inverse electron demand Diels-Alder reactions of 7-methylcoumarin-4-azadienes
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Condensation of 7-methylcoumarin-4-carbaldehyde with different anilines affords 7-methylcoumarin-4-azadienes. The 7-methylcoumarin-4-azadienes do not undergo normal electron demand Diels-Alder reaction with N-phenylmaleimide, but react with dihydropyran, dihydrofuran, and styrene via inverse electron demand Diels-Alder reaction in the presence of anhydrous ZnCl2. The diene involves the azomethine group and the aniline ring. The product is a mixture of two diastereomers in which the major diastereomer has all the hydrogens at the ring junction in cis configuration. This journal is
- Sanap, Kailas K.,Samant, Shriniwas D.
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p. 36696 - 36706
(2015/05/05)
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- Synthesis and photophysical study of novel coumarin based styryl dyes
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New organic dyes comprising phenothiazine, carbazole, indole, diphenylamine moieties, as the electron donors, and coumarin ring as the electron acceptor through ethylenic π bridge were synthesized and characterized. The reaction of different coumarin-4-acetic acids with phenothiazine-3-carbaldehyde in the presence of piperidine in methanol gives highly fluorescent styryl derivatives having cis configuration of ethylenic double bond. Under similar conditions 7-methylcoumarin-4-acetic acid was condensed with indole-3-carbaldehyde, carbazole-3-carbaldehyde, and diphenyl amine aldehyde to give different styryl derivatives with trans configuration of ethylenic double bond. Synthesized compounds were also studied for photophysical properties and show solvatochromism.
- Sanap, Anita K.,Sanap, Kailas K.,Shankarling, Ganapati S.
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p. 190 - 199
(2015/05/13)
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- Synthesis of 3-[(tert-Butyldimethylsilyl)oxy]glutaric anhydride from citric acid
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A new synthesis of 3-[(tert-butyldimethylsilyl)oxy]glutaric anhydride has been developed from citric acid, which is a commodity chemical and more than a million tons are produced every year by fermentation. The new synthetic approach demonstrated an efficient utilization of bioresource for the synthesis of intermediate of rosuvastatin.
- Jiang,Wang
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p. 7867 - 7868
(2015/02/02)
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- Synthesis of aromatic carbamates derivatives with a chromen-2-one fragment
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Condensation of methyl N-(3-hydroxyphenyl)carbamate with ethyl trifluoromethylacetoacetate, 2-methoxyethyl acetoacetate in the presence of conc. sulfuric acid, and also with acetonedicarboxylic acid formed in situ from citric acid under the action of conc. sulfuric acid afforded chromene derivatives. The esterification of 2-{7-[(methoxycarbonyl)amino]-2-oxo-2H-chromen-4-yl}acetic acid with methanol in the presence of TsOH provided the corresponding ester. The oxidation of its α-methylene group with selenium dioxide led to the formation of methyl 2-{7-[(methoxycarbonyl)amino]-2-oxo-2H-chromen-4-yl}-2-oxo-acetate entering into a condensation with o-phenylenediamine resulting in a derivative with a dihydroquinoxaline fragment. The reaction of phenyl N-(4-formylphenyl)carbamate with 3-acetyl-2H-chromen-2-one in butanol in the presence of catalytic quantity of piperidine and acetic acid furnished 4-[(E)-3-oxo-2H-chromen-3-yl)-1-propenyl]phenyl N-phenylcarbamate.
- Velikorodov,Ionova,Melent'eva,Stepkina,Starikova
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p. 1112 - 1116
(2015/02/02)
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- Regiospecific normal Diels-Alder reaction of trans -1,2- biscoumarinylethenes
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The reaction of different 7,8-substituted coumarin 4-acetic acids with 7-diethylaminocoumarin-3-carbaldehyde in the presence of piperidine in methanol gives 1,2-biscoumarinylethenes. These compounds undergo regiospecific Diels-Alder reactions at their electron-rich diene components CCCC with electron-deficient dienophiles. The feasibility of normal electron-demand Diels-Alder reactions could be explained on the basis of the HOMO-LUMO gap. All the compounds are new and are intensely colored. Georg Thieme Verlag Stuttgart ? New York.
- Sanap, Kailas K.,Samant, Shriniwas D.
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p. 2189 - 2194
(2012/10/30)
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- Synthesis, anti-tubercular activity and 3D-QSAR study of coumarin-4-acetic acid benzylidene hydrazides
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A set of 25 coumarin-4-acetic acid benzylidene hydrazides were synthesized and characterized by NMR, IR and mass spectroscopic techniques. The compounds were evaluated for their anti-tubercular activity against Mycobacterium tuberculosis H37Rv strain using the BACTEC 460 system to determine percentage inhibition. To understand the relationship between structure and activity, a 3D-QSAR analysis has been carried out by Comparative Molecular Field Analysis (CoMFA). Several statistically significant CoMFA models were generated. The CoMFA model generated with database alignment was the best in terms of overall statistics. The CoMFA contours provide a good insight into the structure activity relationships of the compounds reported herein.
- Manvar, Atul,Malde, Alpeshkumar,Verma, Jitender,Virsodia, Vijay,Mishra, Arun,Upadhyay, Kuldip,Acharya, Hrishikesh,Coutinho, Evans,Shah, Anamik
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p. 2395 - 2403
(2008/12/23)
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- Cerium(III) catalysis in acid bromate oxidation of citric acid in the presence of bromo-complex-forming metal ions
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Cerium(III) ion-catalysed bromate oxidation of citric acid in aqueous acetic acid media containing HClO4 and mercury(II), a bromo-complex-forming metal ion, exhibits first-order in [bromate] and less than unit order in [citric acid] and [cerium(III)]. Reaction rate increases linearly with an increase in [HClO4]. However, an opposite effect is observed with [H2SO4] and [NaHSO4]. D2O and Hg(OAc)2 have insignificant effect on the rate of reaction. The catalytic effect of CeIII ion is displayed by its complex forming ability and in the proposed mechanism it is assumed that acid bromate reacts with the CeIII-citric acid binary complex, whose formation (Kc) is precedent to the bromate-cerium(III) reaction, and results a ternary complex (Kf), which subsequently decomposes (kd) into products with the regeneration of CeIII. The effects of ionic strength and dielectric constant of the media are also in accordance with the proposed mechanism. The reaction constants (Kc, Kf and kd) involved in the envisaged mechanism are evaluated. There is a good agreement between the observed and the calculated rate constants under different experimental conditions.
- Reddy, Cherkupally Sanjeeva
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p. 165 - 170
(2008/03/11)
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- Synthesis of some novel 4-substituted coumarins having potential biological activity (Part II)
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Coumarin 4-methyl acetates are oxidized to coumarin-4-methyl glyoxalate using SeO2. Unlike the oxidative decarboxylation observed in the case of coumarin-4-acetic acid, here the oxidation is very selective for the active methylene group, without affecting the COOH group protected with ester function. The product thus obtained is analogous to the phenyl glyoxalic acid methyl ester i.e., coumarin-4-methyl glyoxalate and can be a useful moiety for the various synthetic manipulations of heterocycles substituted at 4-position of the coumarin.
- Mashelkar,Audi
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p. 967 - 971
(2007/10/03)
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- Synthesis of novel 6-substituted-aminopyridin-2(H)-ones
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6-Substituted-amino-4-(4-ethoxyphenyl)-1-phenylpyridin-2(H)-ones 4,5 have been prepared from citric acid. It is treated with conc. H2SO 4 and then with phenetole to give β-arylglutaconic acid which on fusion with arylamine results in 4-(4-ethoxyphenyl)-1-aryl-5-H-pyridine-2,6- diones 2. When 2 (Ar=phenyl) is reacted with phosphorous oxychloride it gives 6-chloro-4-(4-ethoxyphenyl)-1-phenylpyridin-2(H)-one 3, which on treatment with secondary amines yields 6-substituted-amino-4-(4-ethoxyphenyl)-1-phenylpyridin- 2(H)-ones 4 and 5. When 4 and 5 are subjected to azo coupling with different aryldiazonium chlorides furnish two isomers 6-substituted-amino-4-(4- ethoxyphenyl)-1-phenyl-3-(arylazo)pyridin-2(H)-ones 6a-j and 7a-j and 6-substituted-amino-4-(4-ethoxyphenyl)-1-phenyl-5-(arylazo)pyridin-2(H)-ones 6k-t and 7k-t. However, the Mannich reaction on 4 and 5 gives only single product identified as 6-substituted-amino-4-(4-ethoxyphenyl)-1-phenyl-3- (aminomethyl)pyridin-2(H)-ones 8a-b and 9a-b. All the compounds have been characterized by elemental analysis, IR and NMR spectral data.
- Patel,Patel
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p. 1774 - 1778
(2007/10/03)
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- Evaluation of individual rate constants and activation parameters of acid bromate oxidation of hydroxy acids catalysed by aquachlororuthenium complex
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The oxidation of citric and malic acids by bromate in acidic aqueous solutions is catalysed by aquachlororuthenium complex and the kinetics of the reaction is investigated.The rate law is interpreted by a mechanism involving the oxidation of Ru(III) to Ru(V) by oxidant (Kf), followed by a complex formation (Kc) between Ru(V) and substrate, which decomposes (kd) to products in a slow rate determining step with regeneration of Ru(III).All individual rate constants are determined at different temperatures and their activation parameters are also evaluated and discussed.
- Reddy, Ch. Sanjeeva,Kumar, T. Vijaya
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p. 871 - 877
(2007/10/03)
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- Kinetics and mechanism of palladium(II) catalysed oxidation of some hydroxyacids by N-bromosuccinimide in perchloric acid medium
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The kinetics of oxidation of palladium(II) catalysed oxidation of some hydroxyacids, viz., malic, citric and tartaric acids by N-bromosuccinimide have been studied in perchloric acid medium in the presence of mercuric acetate.A first order dependence of rate each in and has been observed.The order of reaction in substrate decreases at higher .A retarding effect of +> on the rate has also been observed.A suitable mechanism consistent with observed kinetic data is proposed and discussed.
- Saxena, Rashmi,Upadhyay, S. K.
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p. 1060 - 1063
(2007/10/02)
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- Oxidative behaviours and relative reactivities of some α-hydroxy acids towards bromate ion in hydrochloric acid medium
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The oxidation kinetics of some α-hydroxy acids by potassium bromate in dilute hydrochloric acid medium have been studied. The reactions are first order with respect to bromate ion. α-hydroxy acid and hydrogen ion concentrations. The reaction rate is governed by two factors : (i) the ease with which the protonated hydroxy acid is produced and (ii) the stability of the intermediate (1:1) bromate ester. The activation parameters of the reactions have been compared. The plausible mechanism of the oxidation process has been suggested. The reactivity of the α-hydroxy acids towards bromate ion are as follows: 9-hydroxy-9-carboxy fluorene> atrolactic acid> mandelic acid> benzilic acid> α-hydroxyisobutyric acid> lactic acid> glycolic acid.
- Gupta, Kalyan Kali Sen,Banerjee, Amalendu,Chatterjee, Hrishikesh
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p. 5323 - 5330
(2007/10/02)
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- Alkylation of methylenedimalonic and acetonedicarboxylic esters by dihalogenoalkanes in the presence of potassium carbonate in dimethyl sulfoxide
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The alkylation of methylenedimalonic ester with methylene bromide, dibromoethane, and 1,3-dibromopropane in the presence of potassium carbonate in DMSO is a convenient method for the synthesis of 1,1,3,3-tetraethoxycarbonylcycloalkanes.The alkylation of acetonedicarboxylic ester leads to the products from either C,C- or C,O-alkylation, depending on the halide and on the reaction conditions.
- Zefirov, N. S.,Sadovaya, N. K.,Kombarova, S. V.
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p. 101 - 104
(2007/10/02)
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- Preparation having excellent absorption property
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A preparation containing an absorption promoter selected from specific classes of water-soluble macromolecular compounds having chelating activity, preferably in the presence of a salt at a concentration such that the composition exhibits higher osmotic pressure than isotonic sodium chloride solution, and a medicine is found to promote absorption of the medicine through a gastrointestinal organ such as the colon, rectum, or vagina.
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- Synthesis of 3-(2'-mercaptophenyl)pent-2-ene-1,5-dioic acid
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A modified method has been developed to synthesize 3-(2'-mercaptophenyl)pent-2-ene-1,5-dioic acid (3).The IR, PMR and mass spectral data of this compound are in agreement with the proposed structure.Starting from 3 the sequence of reactions leading to the formation of 3-(2'-mercaptophenyl)-4-aminobutyric acid (14) does not proceed as expected, instead it gives 2(H)-oxo-3,4-dihydro-1-benzothiopyran-4-acetic acid (15).
- Ranade, V. R.,Deodhar, K. D.,Kulkarni, R. A.
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p. 500 - 502
(2007/10/02)
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- Kinetics of Oxidation of Citric Acid by Cerium(IV)
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Oxidation of citric acid by Ce(IV) sulphate is first order with respect to both the reactats.Kinetic evidences show that reaction proceeds via the formation of an unstable complex and through a free-radical mechanism.The neutral sulphates including cerous sulphate tend to retard the rate.The influence of H(+) has been carefully examined with a view to deciding the nature of reactive species.The activation parameters are Ea = 17.7 kcal/mole, A = 9.65E13 lit. mole-1 sec-1 and ΔS = 2.37 E.U.
- Tripathy, S. N.,Prasad, R. K.
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p. 214 - 217
(2007/10/02)
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- Process for carboxylating organic substrates with carbon dioxide in hydrocarbon solvents
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Carboxylable substrates i.e., ketones, esters, nitroparaffins and nitriles, containing activated hydrogen atoms are carboxylated by reaction with alkaline phenates and CO2 in at least one hydrocarbon solvent selected from aliphatic, alicyclic, aromatic and alkyl-aromatic hydrocarbon solvents.
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