- Synthesis of Non-symmetrical Dispiro-1,2,4,5-Tetraoxanes and Dispiro-1,2,4-Trioxanes Catalyzed by Silica Sulfuric Acid
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A novel protocol for the preparation of non-symmetrical 1,2,4,5-tetraoxanes and 1,2,4-trioxanes, promoted by the heterogeneous silica sulfuric acid (SSA) catalyst, is reported. Different ketones react under mild conditions with gem-dihydroperoxides or peroxysilyl alcohols/β-hydroperoxy alcohols to generate the corresponding endoperoxides in good yields. Our mechanistic proposal, assisted by molecular orbital calculations, at the ωB97XD/def2-TZVPP/PCM(DCM)//B3LYP/6-31G(d) level of theory, enhances the role of SSA in the cyclocondensation step. This novel procedure differs from previously reported methods by using readily available and inexpensive reagents, with recyclable properties, thereby establishing a valid alternative approach for the synthesis of new biologically active endoperoxides.
- Amado, Patrícia S. M.,Coelho, Jaime A. S.,Cristiano, Maria L. S.,Frija, Luís M. T.,O'neill, Paul M.
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p. 10608 - 10620
(2021/07/31)
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- Functionalized nanomagnetic graphene by ion liquid containing phosphomolybdic acid for facile and fast synthesis of paracetamol and aspirin
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A nanocomposite has been synthesized by supporting of polyaniline-modified polyoxometalate-paired poly(ionic liquid) on the surface of magnetic graphene and characterized by various techniques. The fabricated nanocomposite was found to be a versatile catalyst for the synthesis of paracetamol and aspirin drugs showing high activity and selectivity. The observed high catalytic activity of the newly synthesized catalyst, in the preparation of these two important drugs, can be attributed to the presence of graphene, which provides high surface area for the supporting of polyaniline–polyoxometalate pair and also to the strong acidity of the solid acid. This catalytic system has several advantages, such as simple experimental process, easy separation of the product, solvent-free condition, efficient isolation, and recovery of the magnetic catalyst as well as high reusability.
- Nasiri, Elahe,Kooshki, Feridoon,Kooti, Mohammad,Rezaeinasab, Rezvan
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- Method for promoting acylation of amine or alcohol by carbon dioxide
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The invention relates to a method for promoting acylation of amine or alcohol by carbon dioxide, which comprises the following steps of: mixing an amine compound, carboxylate or thiocarboxylate compound and a reaction solvent under the action of carbon dioxide, and reacting to obtain an amide compound, or under the action of carbon dioxide, mixing the alcohol compound, the thiocarboxylate compound and the reaction solvent [gamma]-valerolactone, and reacting to obtain the ester compound. According to the invention, under the promotion action of carbon dioxide, carboxylate or thiocarboxylate is used as an acylation reagent, and amine and alcohol are converted into amide and ester compounds in the absence of a transition metal catalyst, so that acylation reagents such as acyl chloride or anhydride with irritation and corrosivity are avoided; and the method has the advantages of simple operation, mild reaction conditions, high tolerance of substrate functional groups, strong applicability and high yield, and provides an efficient, reliable and economical preparation method for synthesis of amide and ester compounds.
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Paragraph 0034-0035
(2021/05/29)
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- PYRROLE DERIVATIVES AS PLK1 INHIBITORS
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The invention provides compounds of the formula (3): or a pharmaceutically acceptable salt or tautomer thereof. The compounds are useful in the treatment of cancers.
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Page/Page column 111; 112
(2018/11/22)
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- Efficient synthesis of (R)-phenylephrine using a polymer-supported Corey-Bakshi-Shibata catalyst
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An efficient and mild synthetic route to (R)-phenylephrine hydrochloride using Corey-Bakshi-Shibata (CBS) catalyst was reported. In order to avoid a lengthy recovery process of the catalyst from homogeneous reaction, a polymer-supported CBS catalyst was prepared, and a preliminary attempt was made to achieve a continuous reduction on a laboratory scale, which contributes to synthesis of (R)-phenylephrine in a cost-effective way.
- Dai, Shuangxiong,Li, Guohua,Zhang, Wenbo,Zhang, Cuiyan,Song, Xiaoling,Huang, Di
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supporting information
p. 740 - 743
(2017/05/16)
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- Hydration of aromatic terminal alkynes catalyzed by iron(III) sulfate hydrate under chlorine-free conditions
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The hydration of aromatic terminal alkynes performed in acetic acid in the presence of catalytic hydrate ironIII sulfate, Fe2(SO 4)3·nH2O (4-9 mol %), yields the derived aryl methyl ketones with good to excellent yields. Under comparable conditions (18 mol %, 95 C, 24 h), bifunctional substrates were transformed into the monoacetyl or the diacetyl derivatives, depending on the structure of the aromatic diyne. The reaction is compatible with aryl substituents of different nature and ring positions, including hydroxyl, carbonyl groups, and cumulated hydrocarbons. The soft character of the non nucleophilic sulfate anion allows for activation of the triple bond toward carbonoxygen bond formation in the Br?nsted acidic medium. The proposed protocol is based on readily available and non toxic materials, in the absence of chlorine atoms in either the solvent or the metal catalyst.
- Bassetti, Mauro,Ciceri, Samuele,Lancia, Federico,Pasquini, Chiara
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supporting information
p. 1608 - 1612
(2014/03/21)
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- Synthesis and biological evaluation of glucagon-like peptide-1 receptor agonists
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In this study, a series of fused-heterocyclic derivatives were systematically designed and synthesized using an efficient route, and evaluated in terms of GLP-1R agonist activity. We employed short synthetic steps and reactions that are tolerant of the presence of various functional groups and suitable for parallel operations to enable the rapid generation of libraries of diverse and structurally complex small molecules. Of the compounds synthesized, 3-(8-chloro-6-(trifluoromethyl)imidazo[1,2-a] pyridin-2-yl)phenyl methanesulfonate (8e) was the most potent agonist with an EC50 of 7.89 μM, and thus is the compound with the greatest potential for application. These findings represent a valuable starting point for the design and discovery of small-molecule GLP-1R agonists that can be administered orally.
- Zhang, Yu-Juan,Shen, Liu-Lan,Cheon, Hyae-Gyeong,Xu, Yong-Nan,Jeong, Jin-Hyun
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p. 588 - 599
(2014/06/09)
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- Trifluoroacetic acid-catalyzed synthesis of N -(1-(3-chlorophenyl)-3-aryl- 3-oxopropyl)-2-(4-nitrophenyl)acetamides via Dakin-west reaction
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A series of novel N-(1-(3-chlorophenyl)-3-aryl-3-oxopropyl)-2-(4- nitrophenyl) acetamides were synthesized using p-nitrophenylacetonitrile, m-chlorobenzaldehyde, and aryl methyl ketones as starting materials and trifluoroacetic acid (TFA) as catalyst. This realized an improved Dakin-West reaction in which p-nitrophenylacetonitrile was involved. The chemical structures of up to 15 target molecules were characterized by 1H NMR, 13C NMR, and high-resolution mass spectrometry. This method provides a facile synthetic protocol under more moderate reaction conditions, smaller dosage (0.40 mol%) and hence lower cost of catalyst, and simpler posttreatment in comparison to other known methods. A reaction mechanism is proposed in which hydroxyacetophenone is first catalytically converted into the corresponding acetoxyacetophenone prior to be involved in the subsequent Dakin-West reaction that eventually leads to hydroxyl-acetylated target compounds. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Tian, Hui-Hui,Fan, Li,Zhang, Xing-Hua,Zhou, Cheng-He,Zhou, Guang-Ming,Yang, Da-Cheng
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p. 170 - 180
(2013/12/04)
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- Acetylation of alcohols and phenols with acetic anhydride under solvent-free conditions using an ionic liquid based on morpholine as a recoverable and reusable catalyst
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Rapid and efficient acetylation of alcohols and phenols with acetic anhydride is performed in the presence of economical Bronsted acidic ionic liquids that bear a propanesulfonic acid group on a morpholinium cation as catalysts under solvent-free conditions. [MMPPA][HSO4] (N-methylmorpholinium propanesulfonic acid ammonium hydrogensulfate) was proven to be the most active catalyst, and after removal of water, it could be recycled and reused for up to four times without a noticeable decrease in catalytic activity. Springer-Verlag 2010.
- Yue, Caibo,Liu, Qingqing,Yi, Tingfeng,Chen, Yun
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experimental part
p. 975 - 978
(2011/09/30)
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- Copper(II) Tetrafluoroborate-Catalyzed Acetylation of Phenols, Thiols, Alcohols, and Amines
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Copper(II) tetrafluoroborate efficiently catalyzes acetylation of structurally diverse phenols, alcohols, thiols, and amines with stoichiometric amounts of Ac2O under solvent-free conditions at room temperature. Acid-sensitive alcohols are smoothly acetylated without competitive side reactions. The reaction is influenced by the steric and electronic factors associated with the substrate as well as the anhydride. Acetylation of a sterically hindered substrate requires excess of anhydride and longer time. Acylation with less electrophilic anhydrides affords poor to moderate yields.
- Chakraborti, Asit K.,Gulhane, Rajesh,Shivani
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p. 111 - 115
(2007/10/03)
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- Mg(ClO4)2 as a powerful catalyst for the acylation of alcohols under solvent-free conditions
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A trace amount of magnesium perchlorate (from 0.1 mol% to 1 mol%) is able to promote quantitative acylation, with anhydrides, of a large variety of functionalized alcohols in short times, at room temperature and under solvent-free conditions.
- Bartoli, Giuseppe,Bosco, Marcella,Dalpozzo, Renato,Marcantoni, Enrico,Massaccesi, Massimo,Rinaldi, Samuele,Sambri, Letizia
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- Bismuth Oxide Perchlorate as a Highly Efficient Catalyst for Heteroatom Acylation under Solvent-Free Conditions
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Bismuth oxide perchlorate efficiently catalyzes the acetylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Sterically hindered and electron deficient phenols are acetylated in excellent yields with stoichiometric amounts of Ac2O at room temperature. Acylation of acid-sensitive alcohols is carried out efficiently without competitive side reactions. Optically active substrates are acetylated without any detrimental effect on the optical purity.
- Chakraborti, Asit K.,Gulhane, Rajesh,Shivani
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p. 1805 - 1808
(2007/10/03)
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- Indium(III) chloride as a new, highly efficient, and versatile catalyst for acylation of phenols, thiols, alcohols, and amines
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Indium(III) chloride efficiently catalyses the acylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Acid sensitive alcohols are smoothly acylated without competitive side reactions. Acylation of 2-hydroxynaphthalene is carried out with carboxylic acids adopting the mixed anhydride protocol using trifluoroacetic anhydride.
- Chakraborti, Asit K.,Gulhane, Rajesh
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p. 6749 - 6753
(2007/10/03)
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- Electrostatic catalysis by ionic aggregates: Scope and limitations of Mg(ClO4)2 as acylation catalyst
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Alkali and alkaline earth metal perchlorates exhibit electrostatic catalysis in the activation of anhydrides for the acylation reaction. Perchlorates with higher values of the charge-size function of the metal ion exhibit better catalytic activity following the order Mg(ClO4) 2>Ba(ClO4)2>LiClO4. Acylation of structurally diverse phenols, thiols, alcohols, and amines have been carried out with stoichiometric amounts of anhydride at room temperature under solvent free conditions in the presence of catalytic amount of Mg(ClO4) 2. Sterically hindered and electron deficient phenols are efficiently acylated. Acylation with sterically hindered anhydrides such as iso-butyric, pivalic, and benzoic anhydrides are carried out with phenols and alcohols in excellent yields. Acid-sensitive alcohols are acylated in excellent yields without any competitive side reactions.
- Chakraborti, Asit K.,Sharma, Lalima,Gulhane, Rajesh,Shivani
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p. 7661 - 7668
(2007/10/03)
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- Efficient one-pot formation of amides from benzyl carbamates: Application to solid-phase synthesis
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A convenient one-pot protocol for the conversion of benzyl carbamates to amides is described. The general applicability of the procedure is illustrated using various types of substrates. This new method proceeds rapidly under mild conditions, in good yields, and without noticeable racemization. This protocol was applied to solid-phase synthesis to prepare amides and esters from Merrifield resin-bound carbamates and carbonates. (C) 2000 Elsevier Science Ltd.
- Li, Wen-Ren,Yo, Ying-Chih,Lin, Yu-Sheng
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p. 8867 - 8875
(2007/10/03)
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- Lewis acid-catalyzed cleavage of carbamate and carbonate resins
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A procedure for the preparation of amides and esters on a Merrifield resin-bound benzyloxycarbonyl equivalent has been developed. Polymer-supported carbamates react cleanly with zinc bromide and the appropriate acyl halide in the presence of triethylamine to provide their corresponding amides in high yields and purities. Cleavage of resin-bound carbonates was carried out using the similar reagent systems in the absence of triethylamine to give acetates or benzoates. (C) 2000 Elsevier Science Ltd.
- Li,Lin,Yo
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p. 6619 - 6622
(2007/10/03)
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- Preparation of m-acylphenol derivatives by the reaction of tricarbonyl(cyclohexadienone)iron complex and higher order cuprates
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Reaction of tricarbonyl[(2,3,4,5-η)-2,4-cyclohexadien-1-one]iron and higher order cuprates followed by the treatment with acetic anhydride and then with carbon monoxide affords tricarbonyl[(1,2,3,4-η)-1-acetoxy-5-endo-acyl-1,3-cyclohexadiene]iron complexe
- Ban, Sooho,Sakurai, Hidehiro,Hayashi, Yujiro,Narasaka, Koichi
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p. 699 - 700
(2007/10/03)
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