cas 93-97-0, Benzoic anhydride | Articles data

Articles about 93-97-0Total 201 be found

Article title
Article abstract
Author
Journal number and time
Download

The effect of microwave irradiation on carbodiimide-mediated esterifications on solid support
The esterification of a polymer-supported alcohol (PS Wang resin) with benzoic acid was investigated using microwave irradiation. Activation of the carboxylic acid was carried out using diisopropylcarbodiimide, either via the O-acylisourea or symmetrical anhydride protocols. In the microwave-assisted solid-phase coupling using the O-acylisourea method the main product of the reaction was 1-benzoyl-1,3-diisopropylurea, formed by rearrangement of the thermolabile isourea intermediate. On the other hand, significant rate enhancements were observed for the coupling of benzoic anhydride to Wang resin using microwave flash heating in 1-methyl-2-pyrrolidone as solvent. Reaction times were reduced from 2 to 3 days using conventional conditions, to 10 min by microwave dielectric heating.
Stadler, Alexander,Kappe, C.Oliver
p. 3915 - 3920
(2001)
Read Online

Clay-supported liquid-liquid-solid phase transfer catalysis: Synthesis of benzoic anhydride
Solid-supported phase transfer catalysed reactions typically involve polystyrene supports cross-linked with divinyl benzene. The use of commercially available clay as a support for the PTC reaction is attractive. This paper reports the preparation of benzoic anhydride from benzoyl chloride and sodium benzoate using clay-supported quaternary ammonium salts at 30°C. The selectivity to the product is 100%. The mechanistic and kinetic aspects are also reported. The clay-supported catalyst was found to be more active than polymer-supported catalysts.
Yadav,Naik, Suguna S.
p. 141 - 146
(2000)
Read Online

-
-
Gerrard,Thrush
p. 2117,2119
(1959)
Read Online

Synthesis and in vitro evaluation of taxol oxetane ring D precursors
A series of potential taxoid substrates was prepared in radiolabeled form to probe in vitro for the oxirane formation step and subsequent ring expansion step to the oxetane (ring D) presumably involved in the biosynthesis of the anticancer agent Taxol. None of the taxoid test substrates underwent transformation in cell-free systems from Taxus suggesting that these surrogates bore substitution patterns inappropriate for recognition or catalysis by the target enzymes, or that taxoid oxiranes and oxetanes arise by independent biosynthetic pathways.
Kaspera, Rüdiger,Cape, Jonathan L.,Faraldos, Juan A.,Ketchum, Raymond E.B.,Croteau, Rodney B.
p. 2017 - 2019
(2010)
Read Online

Multifunctional amphiphilic carbonaceous microcapsules catalyze water/oil biphasic reactions
Multifunctional amphiphilic hollow carbonaceous spheres assembled into Pickering emulsions exhibit reversible pH-dependent phase-transfer behavior and can efficiently catalyze water/oil biphasic reactions, facilitating the recycling of the catalysts and separation of the products.
Tan, Hongyi,Zhang, Peng,Wang, Lei,Yang, Dang,Zhou, Kebin
p. 11903 - 11905
(2011)
Read Online

Generation of Oxyphosphonium Ions by Photoredox/Cobaloxime Catalysis for Scalable Amide and Peptide Synthesis in Batch and Continuous-Flow
Phosphine-mediated deoxygenative nucleophilic substitutions, such as the Mitsunobu reaction, are of great importance in organic synthesis. However, the conventional protocols require stoichiometric oxidants to trigger the formation of the oxyphosphonium i
Chen, Xiangyang,Houk, Kendall N.,Mo, Jia-Nan,Su, Junqi,Umanzor, Alexander,Zhang, Zheng,Zhao, Jiannan
supporting information

(2022/01/06)

Preparation method of symmetric aromatic anhydride compound
The invention discloses a preparation method of a symmetric aromatic anhydride compound, the preparation method comprises the following steps: dissolving alpha-terpilenol and pyridine in a solvent, adding an aroyl chloride solution, and reacting for 8-16 hours to obtain the symmetric aromatic anhydride compound. The alpha-terpilenol and the aroyl chloride are used as raw materials, and the method has the advantages of being easy to operate, mild in reaction condition, high in safety, simple in technological process and post-treatment, low in cost, high in yield of part of products and the like, and is very beneficial to industrialization.
-
Paragraph 0053-0054; 0061-0062

(2021/08/11)

Rh(I)-Catalyzed Direct C6?H Arylation of 2-Pyridones with Aryl Carboxylic Acids
A Rh(I)-catalyzed C6-selective C?H arylation of 2-pyridones with inexpensive, readily available, safe and structurally diverse aryl carboxylic acids with the aid of a pyridine directing group is developed. This decarbonylative arylation protocol features an easy-to-handle catalytic system, and is amenable to diversely substituted 2-pyridones and aryl carboxylic acids. It allows access to a wide range of C6-arylated 2-pyridones, including those that are difficult to prepare using conventional C?H arylation processes. The method tolerates various electron-neutral, electron-rich and electron-deficient functional groups, and affords the products in 41–91% yields. (Figure presented.).
Fan, Qinghua,Pan, Yixiao,Walsh, Patrick J.,Xu, Jianbin,Xu, Lijin,Xu, Xin,Yu, Zexin,Zhao, Haoqiang
supporting information
p. 3995 - 4001
(2021/07/02)

METHOD FOR PRODUCING CARBOXYLIC ACID ANHYDRIDE OR SULFONIC ACID ANHYDRIDE
To provide a method for producing carboxylic acid anhydride or sulfonic acid anhydride in which carboxylic acid anhydride or sulfonic acid anhydride is produced in a simple or easy process using carboxylic acid or sulfonic acid as raw material, and using an industrially available raw material and in an efficient process in industrial practice.SOLUTION: Provided is a method for producing carboxylic acid anhydride or sulfonic acid anhydride, which is a method for producing an acid anhydride by reacting carboxylic acid or sulfonic acid and a halogenating agent, and in which a solvent containing a phosphoric acid ester such as the formula (1) is used. (R1, R2 and R3 are the same or non-identical alkyl group or fluorine-containing alkyl group having 1 to 10 carbon atoms, and at least one is fluorine-containing alkyl group.).SELECTED DRAWING: None
-
Paragraph 0050-0051

(2021/02/25)

Size-Induced Inversion of Selectivity in the Acylation of 1,2-Diols
Relative rates for the Lewis base-catalyzed acylation of aryl-substituted 1,2-diols with anhydrides differing in size have been determined by turnover-limited competition experiments and absolute kinetics measurements. Depending on the structure of the anhydride reagent, the secondary hydroxyl group of the 1,2-diol reacts faster than the primary one. This preference towards the secondary hydroxyl group is boosted in the second acylation step from the monoesters to the diester through size and additional steric effects. In absolute terms the first acylation step is found to be up to 35 times faster than the second one for the primary alcohols due to neighboring group effects.
Mayr, Stefanie,Zipse, Hendrik
supporting information
p. 18084 - 18092
(2021/12/02)

Efficient synthesis of symmetrical anhydrides by cross dehydrogenative coupling of aryl aldehydes over CuFe2O4 nanoparticles
Nano copper ferrite catalyst is prepared and characterized by scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, vibrational sample magnetometry, and Fourier transform infrared. The catalytic activity is probed for cross-dehydrogenative coupling of aromatic aldehydes in the presence of tert-butyl hydroperoxide as the oxidant. This catalytic protocol appears as a simple, rather cheap, clean, and efficient practical strategy for the synthesis of symmetrical anhydrides, with proper efficiency (66%). The catalyst can be easily separated from the reaction mixture by an external magnet and reused several times in subsequent reactions, without any measurable loss of its efficiency. Graphic abstract: [Figure not available: see fulltext.]
Eidi, Esmaiel,Kassaee, Mohamad Z.,Nasresfahani, Zahra
p. 461 - 468
(2021/04/09)

Direct Access to α,β-Unsaturated Ketones via Rh/MgCl2-Mediated Acylation of Vinylsilanes
We report herein the facile and practical construction of α,β-unsaturated ketones via rhodium-catalyzed direct acylation of vinylsilanes with readily available and abundant carboxylic acids. This protocol features access to a diverse array of synthetically useful functionalities with moderate to excellent yields. More importantly, the late-stage functionalization of pharmaceuticals was also realized with synthetically useful yield.
Chen, Zi-Yan,Deng, Xue-Zu,Song, Yang,Xue, Fei,Yamane, Motoki,Yue, Yan-Ni
p. 12693 - 12704
(2021/09/28)

Synthesis of oxime nerve agent antidotes
The present invention relates to a new route to bis-quaternary pyridinium oximes which can be utilized to restore activity of acetylcholinesterase inhibited by combination with organophosphates.
-
Page/Page column 6

(2020/05/16)

Isothiourea-Catalyzed Atroposelective N-Acylation of Sulfonamides
We report herein an atroposelective N-acylation of sulfonamides using a commercially available isothiourea catalyst, (S)-HBTM, with a simple procedure. The N-sulfonyl anilide products can be obtained in good to high enantiopurity, which represents a new axially chiral scaffold. The application of the product as a chiral iodine catalyst is also demonstrated for the asymmetric α-oxytosylation of propiophenone.
Ong, Jun-Yang,Ng, Xiao Qian,Lu, Shenci,Zhao, Yu
supporting information
p. 6447 - 6451
(2020/09/02)

Thiourea-Mediated Halogenation of Alcohols
The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
supporting information
p. 12901 - 12911
(2020/11/26)

Benzoyl Fluorides as Fluorination Reagents: Reconstruction of Acyl Fluorides via Reversible Acyl C-F Bond Cleavage/Formation in Palladium Catalysis
This report describes the formation of value-added acyl fluorides by means of palladium-catalyzed acyl-exchange reactions between acyl fluorides and acid anhydrides. This method allows using a simple and commercially available acyl fluoride, benzoyl fluoride, as the fluoride source for the easy and efficient preparation of a variety of more complex acyl fluorides. The results of this study suggest that this reaction proceeds via a reversible acyl C-F bond cleavage/formation at the palladium center.
Ogiwara, Yohei,Hosaka, Shintaro,Sakai, Norio
supporting information
p. 856 - 861
(2020/03/05)

Visible Light-Promoted Friedel-Crafts-Type Chloroacylation of Alkenes to β-Chloroketones
The photoredox chloroacylation of alkenes has been developed as a substitute for the Friedel-Crafts acylation of alkenes to β-chloroketones. The direct generation of acyl radical species from acid chlorides under the photoredox conditions allows the formation of β-chloroketones without dehydrochlorination with the help of KHCO3. The synthetic utility of the current method is demonstrated in the one-pot synthesis of dihydroisoxazole, dihydropyrazole, and dihydropyrimidine-2-thione in 1 mmol scale.
Patil, Dilip V.,Kim, Hun Young,Oh, Kyungsoo
supporting information
p. 3018 - 3022
(2020/04/09)

Tin and copper species dispersed on a metal-organic framework as a new catalyst in aerobic Baeyer-Villiger oxidation: An insight into the mechanism
Metal-organic frameworks (MOF) containing tin and copper metal salts were used as catalysts in the Baeyer-Villiger oxidation of cyclohexanone. The outcome was a synergistic effect on the catalyst's efficiency, which resulted from the simultaneous presence of copper and tin species in the MOF. The catalyst with high metal content showed the intermolecular dehydration of benzoic acid and the formation of benzoic anhydride in a side reaction as well as the Baeyer-Villiger oxidation reaction with a decline in efficiency. The optimized catalyst promoted the Baeyer-Villiger reaction in a high yield without the formation of benzoic anhydride.
Alavijeh, Masoumeh Karimi,Amini, Mostafa M.
(2020/04/08)

PIII-Chelation-Assisted Indole C7-Arylation, Olefination, Methylation, and Acylation with Carboxylic Acids/Anhydrides by Rhodium Catalysis
Rhodium-catalyzed C7-selective decarbonylative arylation, olefination, and methylation of indoles with carboxylic acids or anhydrides by C?H and C?C bond activation have been developed. Furthermore, C7-acylation products can also be generated selectively at a lower reaction temperature in the developed system. The key to the high reactivity and regioselectivity of this transformation is the appropriate choice of an indole N-PtBu2 chelation-assisted group. This method has many advantages, including easy access and removal of the directing group, the use of cheap and widely available coupling agents, no requirement of an external ligand or oxidant, a broad substrate scope, high efficiency, and the formation of a sole regioisomer.
Qiu, Xiaodong,Wang, Panpan,Wang, Dingyi,Wang, Minyan,Yuan, Yu,Shi, Zhuangzhi
supporting information
p. 1504 - 1508
(2019/01/04)

Nucleophilic addition to N-benzoylisoquinolinium cation catalyzed by sodium tetracyanocyclopentadienides
Tetracyanocyclopentadienide-catalyzed nucleophilic addition to an N-benzoylisoquinolinium cation is reported. The reaction is accelerated by the in situ formation of the soluble lipophilic salt of an N-benzoylisoquinolinium cation and a tetracyanocyclopentadienide anion.
Sakai, Takeo,Hattori, Mai,Tada, Akari,Matsuoka, Junpei,Mori, Yuji
p. 703 - 715
(2019/08/01)

PPh3/Selectfluor-Mediated Transformation of Carboxylic Acids into Acid Anhydrides and Acyl Fluorides and Its Application in Amide and Ester Synthesis
By taking the advantage of PPh3/Selectfluor system, carboxylic acids are efficiently converted into the pivotal intermediates acyloxyphosphonium ions that can selectively react with a second carboxylic acid or fluoride to in situ yield the corresponding acid anhydrides or acyl fluorides. The developed protocol features commercially availabile reagents, no involvement of base, room temperature conditions, and simple experimental procedure. Additionally, various amides or esters are readily achieved, respectively, with the addition of amines or alcohols.
Yang, Zhen,Chen, Siwei,Yang, Fang,Zhang, Chenxi,Dou, You,Zhou, Qiuju,Yan, Yizhe,Tang, Lin
p. 5998 - 6002
(2019/08/21)

Decarboxylation with Carbon Monoxide: The Direct Conversion of Carboxylic Acids into Potent Acid Triflate Electrophiles
We report a new strategy for the conversion of carboxylic acids into potent acid triflate electrophiles. The reaction involves oxidative carbonylation of carboxylic acids with I2 in the presence of AgOTf, and is postulated to proceed via acyl hypoiodites that react with CO to form acid triflates. Coupling this chemistry with subsequent trapping with arenes offers a mild, room temperature approach to generate ketones directly from broadly available carboxylic acids without the use of corrosive and reactive Lewis or Bronsted acid additives, and instead from compounds that are readily available, stable, and functional group compatible.
Kinney, R. Garrison,Arndtsen, Bruce A.
supporting information
p. 5085 - 5089
(2019/04/01)

Vilsmeier-Haack reagent mediated synthetic transformations with an immobilized iridium complex photoredox catalyst
An immobilized iridium complex photocatalyst Ir(ppy)2(PDVB-py) was synthesized by immobilization of the iridium complex onto the nanoporous vinylpyridine-divinylbenzene copolymer (PDVB-py). Its application for the synthesis of amides, nitriles, and anhydrides was reported via reactions under the action of the visible-light-driven in situ generated Vilsmeier-Haack reagent from CBr4 in DMF. The results showed that this heterogeneous photocatalyst has extremely high activity and excellent stability to be recycled five times.
Zhi, Peng,Xi, Zi-Wei,Wang, Dan-Yan,Wang, Wei,Liang, Xue-Zheng,Tao, Fei-Fei,Shen, Run-Pu,Shen, Yong-Miao
p. 709 - 717
(2019/01/10)

Organocatalytic Desymmetrisation of Fittig's Lactones: Deuterium as a Reporter Tag for Hidden Racemisation
Highly enantioselective desymmetrisation of Fittig's lactones with alcohols is promoted by bifunctional cinchona squaramides. The reactions were carried out with monodeuterated methanol to detect possible hidden racemisation of the stereogenic centre. Current evidence suggests that racemisation was not a relevant process for most substrates; partial erosion of enantioselectivity was only detected with ortho -substituted aryl derivates. The resultant glutaric acid derivatives possess a scaffold that is common in natural products and the compounds are also useful chiral building blocks for further synthetic endeavours.
Spránitz, Péter,Soregi, Petra,Botlik, Bence Béla,Berta, Máté,Soós, Tibor
p. 1263 - 1272
(2019/02/26)

1,2-Dibromotetrachloroethane: An efficient reagent for many transformations by modified Appel reaction
An efficient and facile method has been developed for the synthesis of alkyl bromides from various alcohols under mild conditions using a triphenylphosphine (PPh 3) /1,2-dibromotetrachloroethane (DBTCE) complex in excellent yields and very short time (5 min). This method can also be applied for the transformation of chiral alcohols to their corresponding bromides in very high enantiomeric excess. The PPh 3 /DBTCE complex is also successfully applied to ring-opening reactions of cyclic ethers in mild conditions. Esterification, amidation, and formation of acid anhydrides under very mild experimental conditions are also successfully accomplished by following a modification of the Appel reaction protocol in this work.
Essiz, Sel?uk,Da?tan, Arif
p. 150 - 156
(2019/05/16)

Visible light-induced transformation of aldehydes to esters, carboxylic anhydrides and amides
A transition metal- and organophotocatalyst free synthesis of esters, carboxylic anhydrides and amides from aldehydes induced by visible-light has been reported. The proposed methodology can be carried out by the use of sunlight or artificial visible light as a blue LED source. The methodology has a very broad applicability and the desired products are obtained in very satisfactory yields.
Gaspa, Silvia,Raposo, Inês,Pereira, Leonor,Mulas, Gabriele,Ricci, Pier Carlo,Porcheddu, Andrea,De Luca, Lidia
supporting information
p. 10711 - 10715
(2019/07/15)

Anhydrides of Arylfuran and Arylpyran Pseudoacids: Formation and Structures; C–O Bond Lengths Trends in Pseudo o-Formylbenzoic Acid Derivatives
Abstract: Three methods for producing anhydrides of arylfuran and arylpyran pseudoacids were explored. These included thermal dehydration, phosgene or thionly chloride activation and decomposition, and dicyclohexylcarbodiimide activation and coupling. Derivatives of the cyclic forms of o-formylbenzoic acid, o-acetylbenzoic acid, 2-carboxyphenylacetaldehyde and of 4,4-dimethyl-3,4-dihydro-3-hydroxy-[1H]-isobenzopyran-1-one were formed including dipseudoanhydides and normal-pseudo anhydrides. Crystal and molecular structures for meso and (R,R/S,S)-bis(1[3H]-isobenzofuranone-3-yl)ether, (R,R/S,S)-bis(3-methyl-1[3H]-isobenzofuranone-3yl)ether, meso (3,4-dihydro-[1H]-isobenzopyran-1-one-3-yl)ether, 3-benzoyloxy-1[3H]-isobenzofuranone, 3-benzoyloxy-3-methyl-1[3H]isobenzofuranone, 3-(4′-nitrobenzoyloxy)-4,4-dimethyl-3,4-dihydro-[1H]-isobenzopyran-1-one, and (1[3H]-isobenzofuranone-3-yl)(4,4,dimethyl-3,4-dihydro-[1H]-isobenzopyran-1-one-3-yl)ether are reported. Endocyclic pseudoacyl C–O bonds are always longer than the exocyclic pseudoacyl C–O bonds. It is possible to refine the previously established C–O bond length dependencies on the pKa (of the conjugate acids) of the leaving groups for 3-substituted 1-[3H]-isobenzofuranones. Of six dipseudoanhydrides studied, conformations are found with exocyclic C–O(ether) linkages synclinal to the endocyclic C–O and away from the ring (exo conformation) in two meso structures, two of three RR/SS forms and in a chiral unsymmetrical form. An endo conformation is observed in one of the RR/SS forms. In three normal-pseudo anhydrides, both endo and exo conformations are observed. Graphic Abstract: Synthetic methods for formation of anhydrides of several arylfuran and arylpyran pseudoacids are described, and the pseudoacyl C–O bond length trends are determined for leaving groups spanning over 30 pKa units.[Figure not available: see fulltext.]
O’Loughlin, Emily,Valente, Edward J.
p. 193 - 205
(2019/07/17)

Synthesis, molecular docking, and pharmacological evaluation of N-(2-(3,5-dimethoxyphenyl)benzoxazole-5-yl)benzamide derivatives as selective COX-2 inhibitors and anti-inflammatory agents
A series of N-(2-(3,5-dimethoxyphenyl)benzoxazole-5-yl)benzamide derivatives (3am) was synthesized and evaluated for their in vitro inhibitory activity against COX-1 and COX-2. The compounds with considerable in vitro activity (IC50 50 values in the range of 0.06–0.71 μM. The in vivo anti-inflammatory activity of these six compounds (3a, 3b, 3d, 3g, 3j, and 3k) was assessed by the carrageenan-induced rat paw edema method. Compounds 3d (84.09%), 3g (79.54%), and 3a (70.45%) demonstrated significant anti-inflammatory activity compared to the standard drug ibuprofen (65.90%) and were also found to be safer than ibuprofen, by ulcerogenic studies. A docking study was done using the crystal structure of human COX-2, to understand the binding mechanism of these inhibitors to the active site of COX-2.
Kaur, Avneet,Pathak, Dharam P.,Sharma, Vidushi,Wakode, Sharad
(2018/05/15)

Synthesis, biological evaluation and docking study of a new series of di-substituted benzoxazole derivatives as selective COX-2 inhibitors and anti-inflammatory agents
A new series of substituted-N-(3,4-dimethoxyphenyl)-benzoxazole derivatives 13a–13p was synthesized and evaluated in vitro for their COX (I and II) inhibitory activity, in vivo anti-inflammatory and ulcerogenic potential. Compounds 13d, 13h, 13k, 13l and 13n exhibited significant COX-2 inhibitory activity and selectivity towards COX-2 over COX-1. These selected compounds were screened for their in vivo anti-inflammatory activity by carrageenan induced rat paw edema method. Among these compounds, 13d was the most promising analogs of the series with percent inhibition of 84.09 and IC50 value of 0.04 μM and 1.02 μM (COX-2 and COX-1) respectively. Furthermore, ulcerogenic study was performed and tested compounds (13d, 13h, 13k, 13l) demonstrated a significant gastric tolerance than ibuprofen. Molecular docking study was also performed with resolved crystal structure of COX-2 to understand the binding mechanisms of newly synthesized inhibitors in the active site of COX-2 enzyme and the results were found to be concordant with the biological evaluation studies of the compounds. These newly synthesized inhibitors also showed acceptable pharmacokinetic profile in the in silico ADME/T analyses.
Kaur, Avneet,Pathak, Dharam P.,Sharma, Vidushi,Wakode, Sharad
p. 891 - 902
(2018/01/22)

Synthesis, biological evaluation and docking study of N-(2-(3,4,5-trimethoxybenzyl)benzoxazole-5-yl) benzamide derivatives as selective COX-2 inhibitor and anti-inflammatory agents
A series of N-(2-(3,4,5-trimethoxybenzyl)-benzoxazole-5-yl)benzamide derivatives (3a–3n) was synthesized and evaluated for its in vitro inhibitory activity against COX-1 and COX-2. The compounds with considerable in vitro activity (IC50 50 in the range of 0.14–0.69 μM. In vivo anti-inflammatory activity of these six compounds (3b, 3d, 3e, 3h, 3l and 3m) was assessed by carrageenan induced rat paw edema method. The compound 3b (79.54%), 3l (75.00%), 3m (72.72%) and 3d (68.18%) exhibited significant anti-inflammatory activity than standard drug ibuprofen (65.90%). Ulcerogenic activity with histopathological studies was performed, and the screened compounds demonstrated significant gastric tolerance than ibuprofen. Molecular Docking study was also performed with resolved crystal structure of COX-2 to understand the interacting mechanisms of newly synthesized inhibitors with the active site of COX-2 enzyme and the results were found to be in line with the biological evaluation studies of the compounds.
Kaur, Avneet,Pathak, Dharam P.,Sharma, Vidushi,Narasimhan, Balasubramanian,Sharma, Prateek,Mathur, Rajani,Wakode, Sharad
p. 191 - 202
(2018/08/23)

Exploiting the Thiobarbituric Acid Scaffold for Antibacterial Activity
Thiobarbituric acid (TBA) has been considered a privileged structure for developing antimicrobial agents. Diversity was obtained at positions N and at C5 through acylation, Schiff base formation, Knoevenagel condensation, and thioamide and enamine formation. The present work describes the synthesis of small libraries based on the TBA moiety and above-mentioned reactions. Preliminary antimicrobial activity screening of the prepared compounds against selected bacteria (both Gram-positive and -negative) showed the best results for the Boc-Phe-TBA derivative. These results could be useful for designing and building libraries based on other amino acids with distinct protecting groups.
Sharma, Anamika,Noki, Sikabwe,Zamisa, Sizwe J.,Hazzah, Heba A.,Almarhoon, Zainab M.,El-Faham, Ayman,de la Torre, Beatriz G.,Albericio, Fernando
p. 1923 - 1930
(2018/09/14)

Synthesis, cyclooxygenase-2 inhibition, anti-inflammatory evaluation and docking study of substituted-n-(3,4,5-trimethoxyphenyl)-benzo[d]oxazole derivatives
Background: Non-steroidal anti-inflammatory drugs are widely used for many years, but the chronic use of NSAID’s leads to gastric side effects, ulceration and kidney problems. These side effects are due to non-selective inhibition of COX-2 along with COX-1. Therefore, it is imperative to develop novel and selective COX-2 inhibitors. Objective: In this paper wehave synthesized a series of novel hybrids comprising of substituted-N-(3,4,5-trimethoxyphenyl)-benzo[d]oxazole derivatives and screened for the treatment of inflammation. Methods: The structures of the obtained compounds were elucidated by elemental and spectral analysis (ATR-FTIR,1 H NMR,13 C NMR, Mass spectroscopy). All of the compounds were evaluated for cyclooxygenase (COX-1/COX-2) inhibitory activity by in vitro enzymatic assay. The compound which showed COX-2 activity (3a-3e, 3g – 3h, 3k, 3m and 3o) was further screened for in vivo anti-inflammatory activity and ulcerogenic liability. Molecular docking study was also performed with resolved crystal structure of COX-2 to understand the binding mechanism of newly synthesized inhibitors in the active site of COX-2enzyme. Results: The in vitro COX-1 and COX-2 inhibitory studies showed that the synthesized compounds potentially inhibited COX-2 (IC50 = 0.04 – 26.41 μM range) over COX-1 (IC50 = 0.98 – 33.33 μM range). The in vivo studies predicted that compounds 3c (70.9%, 0.6±0.22), 3m (68.1%, 1.9±0.41) and 3o (70.4%, 1.7±0.27) produced more efficacy against carrageenan induced paw edema and less ulcerogenic effect, as compared to standard ibuprofen (65.9%, 2.2±0.44). The results of docking studies were found to be concordant with the biological evaluation studies of the prepared compound. Conclusion: Among all the tested compounds, 2-Chloro-N-(2-(3,4,5-trimethoxyphenyl)-benzo[d]oxazol-5-yl)-benzamide (3c) was the most potent anti-inflammatory agent and has less ulcerogenic potential. This series of compound can be explored more for development of safer and more active anti-inflammatory agents.
Kaur, Avneet,Wakode, Sharad,Pathak, Dharam P.,Sharma, Vidushi,Shakya, Ashok K.
p. 660 - 673
(2018/11/06)

Mechanochemical synthesis of primary amides from carboxylic acids using TCT/NH4SCN
A facile and effective approach toward the synthesis of primary amides from carboxylic acids has been developed. In the presence of 2,4,6-trichloro-1,3,5-triazine, a combination of ammonium thiocyanate and potassium carbonate led to the rapid conversion of carboxylic acids into the corresponding amides within five minutes grinding at room temperature. The use of ammonium thiocyanate as the amine source is unprecedented and exclusive formation of primary amides is observed only under the liquid-assisted grinding conditions.
Jaita, Subin,Phakhodee, Wong,Chairungsi, Neeranuch,Pattarawarapan, Mookda
p. 3571 - 3573
(2018/09/10)

Cu-MOF: An efficient heterogeneous catalyst for the synthesis of symmetric anhydrides: Via the C-H bond activation of aldehydes
In this paper, an efficient and straightforward synthetic approach for the preparation of a number of symmetric carboxylic anhydrides was reported using Cu2(BDC)2(DABCO) as an efficient heterogeneous catalyst via the C-H bond activation of aldehydes with excellent yields and simple work up. This C-H bond activation reaction appears simple and convenient, has a wide substrate scope and makes use of cheap, abundant, and easily available reagents. The Cu-MOF catalyst was recycled and reused four times without any loss of catalytic activity.
Ahmadzadeh, Zahra,Mokhtari, Javad,Rouhani, Morteza
p. 24203 - 24208
(2018/07/25)

TBHP/ n -Bu 4 PBr-Promoted Oxidative Cross-Dehydrogenative Coupling of Aryl Methanols: A Facile Synthesis of Symmetrical Carboxylic Anhydride Derivatives
A transition-metal-free oxidative cross-dehydrogenative coupling reaction has been developed for the preparation of symmetrical carboxylic anhydrides through self-coupling dual C-O bond formations of aryl methanols. In the presence of a catalytic amount of tetrabutylphosphonium bromide (TBPB) as transfer agent and aqueous tert -butyl hydroperoxide (TBHP) as oxidant and reactant, methylene groups of aryl methanols were efficiently oxidized to C=O and coupled with the peroxide oxygen from TBHP to form a diverse array of symmetrical carboxylic anhydride derivatives.
Adib, Mehdi,Pashazadeh, Rahim
supporting information
p. 136 - 140
(2017/12/27)

Sc(OTf)3-catalyzed synthesis of anhydrides from twisted amides
A novel synthesis of anhydrides from twisted amides is reported. Sc(OTf)3 catalysis in the presence of water is used to synthesize anhydrides in one step from amides without external nucleophiles. Mechanistic studies indicate that the coordination of the catalyst is critical to induce the challenging N-C activation step. This process further highlights the utility of twisted amides in organic synthesis. Notably, the reaction indicates that twisted amides based on the glutarimide scaffold are more reactive than carboxylic acid anhydrides under the developed conditions, which opens the door to controlled sequential catalysis through amide N-C bond cleavage.
Liu, Yongmei,Liu, Ruzhang,Szostak, Michal
p. 1780 - 1785
(2017/03/09)

Metal-free oxidative self-coupling of aldehydes or alcohols to symmetric carboxylic anhydrides
A metal-free synthesis of symmetrical anhydrides has been developed starting from aldehydes, both aliphatic and aromatic or primary benzylic alcohols. The reaction occurs at room temperature and makes use of trichloroisocyanuric acid (TCCA) as an oxidant providing the desired carboxylic anhydrides in satisfactory yields.
Gaspa, Silvia,Porcheddu, Andrea,De Luca, Lidia
supporting information
p. 2533 - 2536
(2017/06/13)

METHOD FOR PRODUCING CARBOXYLIC ACID ANHYDRIDE AND METHOD FOR PRODUCING CARBOXYLIC ACID ESTER
Provided is a production method whereby corresponding carboxylic acid anhydrides and carboxylic acid esters can be obtained at high yield from various carboxylic acids even without a solvent and near room temperature. A method for producing a carboxylic acid anhydride represented by formula (II), the method comprising reacting a compound represented by formula (I) and a carboxylic acid in the presence of a Group II metal compound having an ionic ligand containing an oxygen atom. A method for producing a carboxylic acid ester, the method comprising reacting a carboxylic acid anhydride produced by the aforementioned method and an alcohol. In formula (I), R1 represents a C1-20 hydrocarbon group. In formula (II), R2 represents a C1-20 hydrocarbon group.
-
Paragraph 0077

(2017/04/18)

An investigation on practical synthesis of carboxylic acid derivatives using p-toluenesulfonyl chloride
Carboxylic acid derivatives are well recognized as important class of reagents frequently used in the preparation of a variety of fine or special chemicals such as amides, esters, peptides, drugs, and dyes. Although several methods were developed for the preparation of these compounds, many of them present difficulties, including low yield, high reaction temperature, harsh reaction conditions, tedious work-up, and incompatibility with scale-up. Methods: The synthesis of carboxylic anhydrides is developed through the reaction of carboxylic acids with TsCl in the presence of K2CO3 and acetonitrile as a solvent under ultrasound irradiation and conventional conditions. In addition, one-pot synthesis of acyl azides was carried out in the presence of produced carboxylic anhydrides and the addition of sodium azide under identical condition. Results: A series of carboxylic anhydrides and acyl azides were synthesized using TsCl under ultrasound irradiation and conventional stirring with simple procedure, mild reaction conditions, high yields, and scale-up ability without any restriction. In most cases, the reaction under ultrasound irradiation was better in both yields and the reaction times compared to the conventional method. Conclusion: A convenient method has been developed for the preparation of carboxylic anhydrides and acyl azides under ultrasound irradiation and conventional stirring. The present method is practical and a highly effective alternative for previous reports. The major advantages of this method are: (i) simplicity of the procedure (ii) high yields and high purity of product (iii) scale-up capacity without considerable limitation in conventional system. Under ultrasound irradiation short reaction times as compared to conventional method are observed; yields are comparable to or better than conventional method.
Eskandari, Parvin,Kazemi, Foad
p. 431 - 439
(2017/07/24)

Anhydrides from aldehydes or alcohols via oxidative cross-coupling
A novel type of metal-free oxidative cross-coupling for the synthesis of symmetrical and mixed anhydrides from aldehydes or benzylic alcohols has been developed. The aldehydes or alcohols were converted in situ into their corresponding acyl chlorides, which were then reacted with an array of carboxylic acids. The methodology has a general applicability, and was successfully employed to prepare either aromatic or aliphatic symmetrical anhydrides and mixed anhydrides, which are very unstable compounds.
Gaspa, Silvia,Amura, Ida,Porcheddu, Andrea,De Luca, Lidia
supporting information
p. 931 - 939
(2017/02/10)

A benzoic anhydride synthesis method
The invention relates to a synthetic method of benzoic anhydride. Clean hydrogen peroxide is used as an oxidant to oxidize benzoin to prepare the benzoic anhydride in the presence of an organic selenium catalyst. The benzoin is a chemical raw material which is easily available, and the benzaldehyde which is low in price can be condensed by virtue of clean benzoin. Hydrogen peroxide is used as the oxidant and is clean, easily available and harmless to the environment; according to the method, no metal catalyst is used, the selenium element is a necessary trace element for organisms and can be metabolized in the human body, the organic selenium catalyst used in the method is ecology-friendly, the method is carried out in a moderate condition, no high-corrosive substance is produced, equipment is slightly damaged and is durable, and the synthetic method is suitable for industrialization.
-
Paragraph 0012; 0013; 0014; 0015; 0016; 0017-0040

(2017/07/23)

Palladium-Catalyzed Ligand-Controlled Selective Synthesis of Aldehydes and Acids from Aryl Halides and Formic Acid
Selective synthesis is in the core of modern organic chemistry. In this communication, a novel ligand-dependent palladium-catalyzed carbonylation procedure for the divergent synthesis of aldehydes and carboxylic acids from easily available aryl halides was established. Under the same reaction conditions, the reaction pathway could be controlled by the ligands applied to give formylated and carboxylated products selectively. Sterically hindered monodentate ligands facilitated the reductive carbonylation and provided aldehydes, whereas bidentate ligands preferred the carboxylation reaction and produced carboxylic acids. A wide range of functional groups were tolerated, and the products were, in general, obtained in moderate to excellent yields.
Wu, Fu-Peng,Peng, Jin-Bao,Meng, Ling-Shen,Qi, Xinxin,Wu, Xiao-Feng
p. 3121 - 3124
(2017/08/29)

Acid anhydrides and the unexpected N,N-diethylamides derived from the reaction of carboxylic acids with Ph3P/I2/Et3N
The formation of acid anhydrides from the phosphorous-mediated activation of carboxylic acids was investigated. Under various systems, activation of benzoic acid in the presence of base led to the formation of benzoic anhydride at different rates depending on the reactivity of the reagents. Using the Ph3P-I2/Et3N combination, most aryl acids were converted into the corresponding anhydrides in high yields within 5-10 min. However, for nitro-substituted derivatives, unexpectedly, N,N-diethylamides were isolated without anhydride formation. These results indicated the pronounced effect of substituents in governing these potential side reactions which can significantly affect the yields of acylation reactions promoted by phosphonium species.
Phakhodee, Wong,Duangkamol, Chuthamat,Wangngae, Sirilak,Pattarawarapan, Mookda
supporting information
p. 325 - 328
(2016/01/12)

One for Many: A Universal Reagent for Acylation Processes
This work describes acylation reactions facilitated by a type of heterocycle-based acyl transfer agent, 2-acyloxypyridazinone. Reactions of 2-acyloxypyridazinone with carboxylic acids yield mixed carbonic anhydride intermediates, which are reactive and could be coupled with a wide range of substrates including acids, amines, alcohols, and thiols. The wide substrate scope, ease of operation (no additive or catalyst), storage and handling stability, and atom-efficiency from recycling the heterocycle carrier make the reported acylating agent attractive for acylation-based coupling reactions.
Moon, Hyun Kyung,Sung, Gi Hyeon,Kim, Bo Ram,Park, Jong Keun,Yoon, Yong-Jin,Yoon, Hyo Jae
supporting information
p. 1725 - 1730
(2016/06/09)

The use of BrCCl3-PPh3 in Appel type transformations to esters, O-acyloximes, amides, and acid anhydrides
Esters, acyloximes, amides and acid anhydrides have been prepared from the respective carboxylic acids, oximes, amines and alcohols by the use of the reagent combination BrCCl3-PPh3. The reactions obviate the handling acyl halides or more aggressive reagents PCl3, POCl3, or SOCl2. Furthermore, the environmentally hazardous CCl4 used in Appel-type reactions is replaced with BrCCl3, a reagent of less environmental concern.
Al-Azani, Mariam,al-Sulaibi, Mazen,al Soom, Nuha,Al Jasem, Yosef,Bugenhagen, Bernhard,Al Hindawi, Bassam,Thiemann, Thies
p. 921 - 932
(2016/08/08)

Ph3P-I2 mediated aryl esterification with a mechanistic insight
In order to better understand the reaction mechanism and to obtain optimal conditions, the Ph3P-I2/Et3N mediated aryl esterification reaction was thoroughly investigated. Using a specific reagent addition sequence, the reaction proceeds remarkably well especially with acidic substrates. 31P NMR studies revealed that the formation of an aryloxyphosphonium salt is crucial in governing the reaction path toward the formation of phenolic esters.
Phakhodee, Wong,Duangkamol, Chuthamat,Pattarawarapan, Mookda
p. 2087 - 2089
(2016/04/26)

Synthesis method for diazepam ketorolac drug intermediate benzoic anhydride
The invention provides a synthesis method for diazepam ketorolac drug intermediate benzoic anhydride. The synthesis method includes the following steps that 12.6 mol of benzoic acid, 300 ml of acetonitrile, 13.5 mol to 13.8 mol of benzamide solution and 0.56 mol of aluminum oxide are added to a reaction container provided with a stirrer, a thermometer and a fractional distillation packing column, the temperature of the solution is raised to 110 DEG C to 115 DEG C, a reaction is conducted for 3-5 h, the temperature of the solution is reduced to 80 DEG C to 85 DEG C, the reaction continues to be conducted for 90-120 min, the temperature of the solution is reduced to 15 DEG C to 20 DEG C, solids are separated out, saline solution washing, dimethylamine washing, dehydrating agent dewatering and reduced pressure distillation are conducted, 130-135 DEG C cut fractions are collected, recrystallization is conducted in cyclohexane, and the crystal benzoic anhydride is obtained.
-
Paragraph 0014; 0015

(2016/11/09)

Metal-free cross-dehydrogenative coupling of aryl aldehydes to give symmetrical carboxylic anhydrides promoted by the TBHP/nBu4PBr system
A novel, efficient, and metal-free dual C–O bond formation reaction for the synthesis of carboxylic anhydrides from aryl aldehydes via cross-dehydrogenative coupling is described. Heating a mixture of aromatic aldehydes and an aqueous solution of tert-butyl hydroperoxide as oxidant in the presence of catalytic nBu4PBr in chlorobenzene at 80?°C for 3?h afforded the corresponding carboxylic anhydrides in good to excellent yields.
Adib, Mehdi,Pashazadeh, Rahim,Rajai-Daryasarei, Saideh,Mirzaei, Peiman,Jamal Addin Gohari, Seyed
supporting information
p. 3071 - 3074
(2016/07/06)

Oxidative self-coupling of aldehydes in the presence of CuCl2/TBHP system: Direct access to symmetrical anhydrides
A simple synthesis of symmetrical anhydrides has been developed. Using tert-butylhydroperoxide (TBHP) as the oxidant and copper(II) chloride as the catalyst in acetonitrile, various aromatic and heteroaromatic aldehydes were reacted to provide symmetrical anhydrides in modest to good yields.
Saberi, Dariush,Shojaeyan, Fatemeh,Niknam, Khodabakhsh
p. 566 - 569
(2016/01/20)

Anion Effects in Oxidative Aliphatic Carbon-Carbon Bond Cleavage Reactions of Cu(II) Chlorodiketonate Complexes
Aliphatic oxidative carbon-carbon bond cleavage reactions involving Cu(II) catalysts and O2 as the terminal oxidant are of significant current interest. However, little is currently known regarding how the nature of the Cu(II) catalyst, including the anions present, influence the reaction with O2. In previous work, we found that exposure of the Cu(II) chlorodiketonate complex [(6-Ph2TPA)Cu(PhC(O)CClC(O)Ph)]ClO4 (1) to O2 results in oxidative aliphatic carbon-carbon bond cleavage within the diketonate unit, leading to the formation of benzoic acid, benzoic anhydride, benzil, and 1,3-diphenylpropanedione as organic products. Kinetic studies of this reaction revealed a slow induction phase followed by a rapid decay of the absorption features of 1. Notably, the induction phase is not present when the reaction is performed in the presence of a catalytic amount of chloride anion. In the studies presented herein, a combination of spectroscopic (UV-vis, EPR) and density functional theory (DFT) methods have been used to examine the chloride and benzoate ion binding properties of 1 under anaerobic conditions. These studies provide evidence that each anion coordinates in an axial position of the Cu(II) center. DFT studies reveal that the presence of the anion in the Cu(II) coordination sphere decreases the barrier for O2 activation and the formation of a Cu(II)-peroxo species. Notably, the chloride anion more effectively lowers the barrier associated with O-O bond cleavage. Thus, the nature of the anion plays an important role in determining the rate of reaction of the diketonate complex with O2. The same type of anion effects were observed in the O2 reactivity of the simple Cu(II)-bipyridine complex [(bpy)Cu(PhC(O)C(Cl)C(O)Ph)ClO4] (3).
Saraf, Sushma L.,Mi?aczewska, Anna,Borowski, Tomasz,James, Christopher D.,Tierney, David L.,Popova, Marina,Arif, Atta M.,Berreau, Lisa M.
p. 6916 - 6928
(2016/07/26)

Encapsulating Palladium Nanoparticles Inside Mesoporous MFI Zeolite Nanocrystals for Shape-Selective Catalysis
Pd nanoparticles were successfully encapsulated inside mesoporous silicalite-1 nanocrystals (Pd@mnc-S1) by a one-pot method. The as-synthesized Pd@mnc-S1 with excellent stability functioned as an active and reusable heterogeneous catalyst. The unique porosity and nanostructure of silicalite-1 crystals endowed the Pd@mnc-S1 material general shape-selectivity for various catalytic reactions, including selective hydrogenation, oxidation, and carbon–carbon coupling reactions.
Cui, Tian-Lu,Ke, Wen-Yu,Zhang, Wen-Bei,Wang, Hong-Hui,Li, Xin-Hao,Chen, Jie-Sheng
supporting information
p. 9178 - 9182
(2016/08/03)

Facile and direct synthesis of symmetrical acid anhydrides using a newly prepared powerful and efficient mixed reagent
An efficient mixed reagent for direct synthesis of symmetrical carboxylic anhydrides from carboxylic acids has been prepared. Carboxylic acids are converted to anhydrides using triphenylphosphine/ trichloroisocyanuric acid under mild reaction conditions at room temperature. Short reaction time, excellent yields of products, low cost, availability of reagents, simple experimental procedure, and easy work-up of the products are the main advantages of the presented method.
Rouhi-Saadabad, Hamed,Akhlaghinia, Batool
p. 479 - 485
(2015/01/30)

Light-enabled synthesis of anhydrides and amides
Recently, we have demonstrated that the photogeneration of Vilsmeier-Haack reagents is possible using only dimethylformamide (DMF) and tetrabromomethane (CBr4) in the bromination of alcohols. Extending these findings to carboxylic acid substrates has produced a mild and facile approach to the in situ formation of symmetric anhydrides, which were conveniently converted to amide derivatives in a one-pot process. The efficient protocols discussed herein are marked by use of UVA LEDs (365 nm), which have reduced the reaction times and come with a low setup cost.
Mccallum, Terry,Barriault, Louis
p. 2874 - 2878
(2015/03/30)

Palladium-catalyzed direct ortho aroylation of 2-phenoxypyridines with aldehydes and catalytic mechanism investigation
A direct ortho aroylation of 2-phenoxypyridines with aldehydes leading to aryl ketones by the use of palladium(II) acetate, tert-butyl hydroperoxide, and chlorobenzene as the catalyst, oxidant, and solvent, respectively, is presented. Intra- and intermolecular kinetic isotope effects, radical trapping, and controlled experiments were carried out to support the proposed catalytic mechanism for the reaction. Syntheses of (2-hydroxyphenyl)(phenyl)methanones and 1-hydroxy-9H-fluoren-9-ones directed from ortho-aroylated 2-phenoxypyridines were demonstrated.
Chu, Jean-Ho,Chen, Shih-Tien,Chiang, Meng-Fan,Wu, Ming-Jung
p. 953 - 966
(2015/03/18)

Alcohol cross-coupling for the kinetic resolution of diols via oxidative esterification
We present an organocatalytic C-O-bond cross-coupling strategy to kinetically resolve racemic diols with aromatic and aliphatic alcohols, yielding enantioenriched esters. This one-pot protocol utilizes an oligopeptide multicatalyst, m-CPBA as the oxidant, and N,N-diisopropylcarbodiimide as the activating agent. Racemic acyclic diols as well as trans-cycloalkane-1,2-diols were kinetically resolved, achieving high selectivities and good yields for the products and recovered diols.
Hofmann, Christine,Schümann, Jan M.,Schreiner, Peter R.
p. 1972 - 1978
(2015/02/19)