- 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
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p. 461 - 468
(2021/04/09)
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- Preparation method of symmetric aromatic anhydride compound
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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 0041-0042
(2021/08/11)
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- 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
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supporting information
p. 10711 - 10715
(2019/07/15)
-
- 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
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p. 1263 - 1272
(2019/02/26)
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- 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
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p. 709 - 717
(2019/01/10)
-
- 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
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p. 5998 - 6002
(2019/08/21)
-
- 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)
-
- 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
-
-
- 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
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p. 891 - 902
(2018/01/22)
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- 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
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p. 191 - 202
(2018/08/23)
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- 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.
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p. 660 - 673
(2018/11/06)
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- Cu-MOF: An efficient heterogeneous catalyst for the synthesis of symmetric anhydrides: Via the C-H bond activation of aldehydes
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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
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p. 24203 - 24208
(2018/07/25)
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- Anhydrides from aldehydes or alcohols via oxidative cross-coupling
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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
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supporting information
p. 931 - 939
(2017/02/10)
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- An investigation on practical synthesis of carboxylic acid derivatives using p-toluenesulfonyl chloride
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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
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p. 431 - 439
(2017/07/24)
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- Metal-free oxidative self-coupling of aldehydes or alcohols to symmetric carboxylic anhydrides
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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
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p. 2533 - 2536
(2017/06/13)
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- Acid anhydrides and the unexpected N,N-diethylamides derived from the reaction of carboxylic acids with Ph3P/I2/Et3N
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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
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supporting information
p. 325 - 328
(2016/01/12)
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- One for Many: A Universal Reagent for Acylation Processes
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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
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supporting information
p. 1725 - 1730
(2016/06/09)
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- Oxidative self-coupling of aldehydes in the presence of CuCl2/TBHP system: Direct access to symmetrical anhydrides
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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
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supporting information
p. 566 - 569
(2016/01/20)
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- Facile and direct synthesis of symmetrical acid anhydrides using a newly prepared powerful and efficient mixed reagent
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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
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p. 479 - 485
(2015/01/30)
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- Synthesis of acylsilanes by copper(I)-catalyzed addition of silicon nucleophiles onto acid derivatives
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The transition metal-catalyzed transfer of silicon nucleophiles onto various electrophiles has recently gained considerable attention, due to the now readily available silicon pro-nucleophiles such as silylboronates. Our interest lies in the addition of such species to acid derivatives for the generation of acylsilanes. We report herein an efficient method to synthesize these compounds, starting from easy-to-form anhydrides, with very good yields. Copyright
- Cirriez, Virginie,Rasson, Corentin,Riant, Olivier
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supporting information
p. 3137 - 3140
(2013/12/04)
-
- Efficient generation of hydrogen peroxide by aerobic photooxidation of 2-propanol using anthraquinone-2-carboxylic acid and one-pot epoxidation of α,β-unsaturated ketones
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We developed an efficient method for the generation of hydrogen peroxide by aerobic photooxidation of 2-propanol using anthraquinone-2-carboxylic acid and molecular oxygen in air and visible light from fluorescent lamps. One-pot epoxidation of α,β-unsaturated ketones using the generated hydrogen peroxide is also reported.
- Cui, Lei,Furuhashi, Sohei,Tachikawa, Yuma,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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p. 162 - 165
(2013/02/21)
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- Carboxylic acid anhydrides via Pd-catalyzed carbonylation of aryl halides at atmospheric CO pressure
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A convenient method has been developed, which allows for the direct transformation of aryl iodides into the corresponding carboxylic acid anhydrides via Pd-catalyzed carbonylation under atmospheric CO pressure. The Royal Society of Chemistry 2012.
- Li, Yang,Xue, Dong,Wang, Chao,Liu, Zhao-Tie,Xiao, Jianliang
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supporting information; experimental part
p. 1320 - 1322
(2012/02/04)
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- A mild, clean, and simple synthesis of symmetrical carboxylic anhydrides from carboxylic acides using a polymer supported tosyl chloride
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The use of polymeric reagents simplifies routine acylation of carboxylic acid because it eliminates the traditional purification. We describe the use of readily available cross-linked poly(4-vinylpyridine) supported tosyl chloride, [P4VP].TsCl, in the suspended solution phase synthesis of symmetrical anhydrides from carboxylic acids in the presence of K2CO3 in high yields and purity. The products can be obtained by filtration and evaporation of the solvent.
- Zarchi, M. A. Karimi,Mirjalili,Kahrizsangi, Z. Shamsi,Tayefi
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experimental part
p. 455 - 460
(2010/08/20)
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- Zinc(0)/dimethylformamide-mediated synthesis of symmetrical carboxylic anhydrides from acid chlorides
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The high yielding synthesis of symmetrical carboxylic anhydrides from acid chlorides mediated by zinc dust in the presence of dimethylformamide is presented. A mechanism involving the reductive insertion of zinc(0) into the C-Cl bond of a Vilsmeier-type iminium intermediate as the crucial step is also proposed.
- Serieys, Audrey,Botuha, Candice,Chemla, Fabrice,Ferreira, Franck,Pérez-Luna, Alejandro
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p. 5322 - 5323
(2008/12/22)
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- Reaction of dicarbonates with carboxylic acids catalyzed by weak Lewis acids: General method for the synthesis of anhydrides and esters
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The reaction between carboxylic acids (RCOOH) and dialkyl dicarbonates [(R1OCO)2O], in the presence of a weak Lewis acid such as magnesium chloride and the corresponding alcohol (R1OH) as the solvent, leads to the esters RCOOR1 in excellent yields. The mechanism involves a double addition of the acid to the dicarbonate, affording a carboxylic anhydride [(RCO)2O], R1OH and carbon dioxide. The esters arise from the attack of the alcohols on the anhydrides. Exploiting the lesser reactivity of tert-butyl alcohol in comparison with other alcohols, a clean synthesis of both carboxylic anhydrides and esters has been set up. In the former reaction, an acid/Boc2O molecular ratio of 2:1 leads to the anhydride in good to excellent yields, depending on the stability of the resulting anhydride to the usual workup conditions. In the latter reaction, stoichiometric mixtures of the acid and Boc2O are allowed to react with a twofold excess of a primary alcohol, secondary alcohol or phenol (R 2OH) to give the corresponding esters (RCOOR2). Purification of the products is particularly easy since all byproducts are volatile or water soluble. A very easy chromatography is required only in the case of nonvolatile alcohols. A broad variety of sensitive functional groups is tolerated on both the acid and the alcohol, in particular a high chemoselectivity is observed. In fact, no transesterification processes occur with the acid-sensitive acetoxy group and methyl esters. Georg Thieme Verlag Stuttgart.
- Bartoli, Giuseppe,Bosco, Marcella,Carlone, Armando,Dalpozzo, Renato,Marcantoni, Enrico,Melchiorre, Paolo,Sambri, Letizia
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p. 3489 - 3496
(2008/09/19)
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- In vitro optimization of non-small cell lung cancer activity with troxacitabine, L-1,3-dioxolane-cytidine, prodrugs
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L-1,3-Dioxolane-cytidine, a potent anticancer agent against leukemia, has limited efficacy against solid tumors, perhaps due to its hydrophilicity. Herein, a library of prodrugs were synthesized to optimize in vitro antitumor activity against non-small cell lung cancer. N4-Substituted fatty acid amide prodrugs of 10-16 carbon chain length demonstrated significantly improved antitumor activity over L-1,3-dioxolane-cytidine. These in vitro results suggest that the in vivo therapeutic efficacy of L-1,3-dioxolane- cytidine against solid tumors may be improved with prodrug strategies.
- Radi, Marco,Adema, Auke D.,Daft, Jonathan R.,Cho, Jong H.,Hoebe, Eveline K.,Alexander, Lou-Ella M. M.,Peters, Godefridus J.,Chu, Chung K.
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p. 2249 - 2253
(2008/02/01)
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- Photo-oxidation of aldehydes with molecular oxygen in the presence of catalytic bromine or hydrobromic acid
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Aldehydes were found to be oxidized with molecular oxygen to the corresponding carboxylic acid in the presence of catalytic hydrobromic acid or bromine under photo-irradiation.
- Hirashima, Shin-Ichi,Itoh, Akichika
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p. 156 - 158
(2007/10/03)
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- ZnCl2-mediated synthesis of carboxylic anhydrides using 2-acyl-4,5-dichloropyridazin-3(2H)-ones
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ZnCl2 is an efficient catalyst for synthesis of carboxylic acid anhydride from 2-acyl-4,5-dichloropyridazin-3(2H)-ones. Treatment of 2-acyl-4,5-dichloropyridazin-3(2H)-ones with ZnCl2 (0.5 equivalents) and air in refluxing dry THF or
- Park, Yong-Dae,Kim, Jeum-Jong,Kim, Ho-Kyun,Cho, Su-Dong,Kang, Young-Jin,Park, Ki Hun,Lee, Sang-Gyeong,Yoon, Yong-Jin
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p. 371 - 378
(2007/10/03)
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- Synthesis of unsymmetrical ketones by palladium-catalyzed cross-coupling reaction of carboxylic anhydrides with organoboron compounds
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On the basis of fundamental studies on oxidative addition of carboxylic anhydrides to zerovalent palladium complexes to yield acyl(carboxylato)bis(tertiary phosphine)palladium(II) complexes and their reactions with organoboronic acids to yield ketones, a novel catalytic process has been developed. This converts carboxylic anhydrides and organoboron compounds into ketones catalyzed by palladium complexes under mild conditions. The process provides a general, versatile, synthetic method to produce various symmetrical and unsymmetrical ketones with aromatic, aliphatic, and heterocyclic groups. The catalytic cycle is proposed to comprise (a) oxidative addition of a carboxylic anhydride to produce an acyl(carboxylato)palladium intermediate, (b) transmetallation with an organoboron compound to give an acyl(organo)palladium intermediate, and (c) its reductive elimination to yield a ketone. Not only homogeneous catalyst systems but also heterogeneous systems were found to give ketones under mild conditions.
- Kakino, Ryuki,Yasumi, Sayaka,Shimizu, Isao,Yamamoto, Akio
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p. 137 - 148
(2007/10/03)
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- An efficient and simple procedure for preparation of esters and anhydrides from acid chlorides in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) under solvent-free conditions
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A manipulatively one-pot and rapid method for the synthesis of aliphatic and aromatic ester and anhydride from acid chloride and alcohol or potassium salt of carboxylic acid under solvent-free conditions is reported. The reaction has been carried out in excellent yield and short reaction time in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) under solvent-free conditions.
- Hajipour,Mazloumi
-
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- A convenient method for synthesis of symmetrical acid anhydrides from carboxylic acids with trichloroacetonitrile and triphenylphosphine
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Various carboxylic acids are converted into the corresponding carboxylic acid anhydrides treated with trichloroacetonitrile and triphenylphosphine in the presence of triethylamine at room temperature.
- Kim,Jang
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p. 395 - 399
(2007/10/03)
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- A thermal fragmentation of 1,2,4-oxadiazole-4-oxides to nitriles and nitrosocarbonyls
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1,2,4-Oxadiazole-4-oxides undergo clean thermal cleavage in refluxing chlorobenzene or xylene to nitriles and nitrosocarbonyl intermediates, which are either trapped with suitable olefins to afford ene adducts or dimerize and rearrange to anhydrides. (C) 2000 Elsevier Science Ltd.
- Quadrelli,Campari,Mella,Caramella
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p. 2019 - 2022
(2007/10/03)
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- A facile synthesis of acid anhydrides
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A facile synthesis of symmetric and unsymmetric acid anhydrides using phase-transfer catalysis is described. By this method different types of anhydrides can be obtained in high yields under mild conditions even on microscale levels.
- Dubey,Kumar, R. Vinod
-
-
- Synthesis of anhydrides from acyl chlorides under ultrasound condition
-
A convenient and general method for the synthesis of symmetrical anhydrides under ultrasound conditions is described.
- Hu, Yulai,Wang, Jin-Xian,Li, Shihua
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p. 243 - 248
(2007/10/03)
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- Benzoate derivatives of taxol
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This invention relates to a compound of formula I STR1 or a pharmaceutically acceptable salt thereof, in which R2 is a radical of the formula STR2 in which Ra and Rb are independently hydrogen or C1-6 alkyl, said C1-6 alkyl being optionally substituted with hydroxy, phosphono, phosphonooxy, carboxy or di(C1-6 alkyl) amino; or NRa Rb together represents a radical of the formula STR3 in which y is one to three, and Ra is as defined above; Rp and Rr are independently same or different C1-6 alkyl; R1 is hydrogen or a radical Z of the formula STR4 in which Q is --(CH2)f --, optionally substituted with one to six same or different C1-6 alkyl or C3-6 cycloalkyl, or a carbon atom of said --(CH2)f -- radical may also be a part of C3-6 cycloalkylidene; R3 and R4 are independently hydrogen or C1-6 alkyl, or R3 and R4 taken together with the carbon atom to which they are attached form C3-6 cycloalkylidene; R5 is --OC(=O)R, --OP=O(OH)2 or --CH2 OP=O(OH)2, in which R is C1-6 alkyl; R6, R7, R8 and R9 are independently halogen, C1-6 alkyl, C1-6 alkoxy or hydrogen, but when R5 is --OC(=O)R, one of R6, R7, R8 or R9 is --OP=O(OH)2 ; f is 2 to 6; n is O, and m is 1 or 0 when R5 is --CH2 OP=O(OH)2 ; and n is 1 or 0, and m is 1 when R5 is --OC(=O)R or --OP=O(OH)2. Also provided by this invention are pharmaceutical formulations and a method for treating mammalian tumors with a compound of formula I.
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- Solid-liquid phase transfer and cobalt or palladium complex catalyzed synthesis of anhydrides from acyl chlorides
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Acyl chloride can efficiently be converted into anhydride under solid liquid phase transfer catalysis by using bis(triphenylphosphine)cobalt dichloride or bis (triphenylphospine)palladium dichloride as catalyst.
- Wang,Hu,Cui
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p. 3261 - 3268
(2007/10/02)
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- FACILE CONVERSION OF AMIDES TO THE ACIDS AND/OR ANHYDRIDES USING DINITROGEN TETROXIDE
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Carboxamides and sulfonamides were reacted with dinitrogen tetroxide to give the corresponding acids, while such as N-bromoamides and hydroxamic acids were also converted to the corresponding acids together with their anhydrides.
- Kim, Yong Hae,Kim, Kweon,Park, Young Jun
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p. 3893 - 3894
(2007/10/02)
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- Acyl Trimethylsilyl Polyphosphates as Activated Esters in Acylation Reactions
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The preparation and application of a new class of activated esters, acyl trimethylsilyl polyphosphates, are described.These complexes, prepared by the reaction of trimethylsilyl carboxylates with phosphorus pentoxide, are versatile acylating agents under relatively mild conditions.Sodium or potassium halides and imidazole are very effective catalysts leading to the in situ generation of reactive acyl halides and acyl imidazolides.Amines, amides, alcohols and phenols, p-thiocresol, carboxylic acids and trimethylsilyl carboxylates, and hexamethyldisilazane have been acylated to give high yields of amides, imides, esters, thioesters, anhydrides and nitriles, respectively.
- Rao, C. Someswara,Rambabu, M.,Srinivasan, P. S.
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p. 407 - 411
(2007/10/02)
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- PHASE MANAGED ORGANIC SYNTHESIS 3. SYMMETRICAL ANHYDRIDES FROM CARBOXYLIC ACIDS VIA POLYMER ASSISTED REACTION.
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Symmetrical anhydrides are produced quickly and in high yield by treating mixtures of a carboxylic acid and one-half equivalent thionyl chloride in dichloromethane with a solid-state copolymer of 4-vinylpyridine.This conversion is accomplished equally well in batch or column mode.
- Fife, Wilmer K.,Zhang, Zhi-dong
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p. 4937 - 4940
(2007/10/02)
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- A Simple and Mild Esterification Method for Carboxylic Acids Using Mixed Carboxylic-Carbonic Anhydrides
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A simple and mild esterification method using mixed carboxylic-carbonic anhydrides has been developed.Simple aliphatic carboxylic esters are prepared in high yields by the reaction of acids with equimolar amounts of chloroformates (2,2,2-trichloroethyl chloroformate is an exception) and triethylamine in the presence of a catalytic amount of 4-(dimethylamino)pyridine.Although aromatic acids give a mixture of the ester, the acid anhydride, and the carbonate under normal conditions utilized in this study, it is found that increasing the amount of 4-(dimethylamino)pyridine drastically decreases the formation of the acid anhydride and the carbonate, affording a satisfactory yield of the ester.This method reaches a limit with sterically hindered acids and the formation of the acid anhydride and the carbonate is favored.
- Kim, Sunggak,Lee, Jae In,Kim, Youn Chul
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p. 560 - 565
(2007/10/02)
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- Synthesis, Thermal Stability, and Chemiluminescence Properties of Bisdioxetanes Derived from p-Dioxines
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By elimination of methanol from 2,5-dimethoxy-1,4-dioxanes and 2,3-dihydro-2-methoxy-1,4-dioxines on treatment with p-toluenesulfonic acid in acetic anhydride, the new tetrakis(4-methoxyphenyl)-, tetrakis(4-chlorophenyl)-, tetra-p-tolyl-, and 2,5-dimethyl-3,6-diphenyl-1,4-dioxines (1) were prepared in good yields.Photosensitized singlet oxygenation of these 1,4-dioxines 1 afforded the corresponding bisdioxetanes 2, the 1,2-diketones, and the enediol diesters 7.Thermal decomposition of the bisdioxetanes 2 yielded the corresponding anhydrides 4 essentially quantitatively.During the thermolysis of 1,6-dimethyl-3,8-diphenyl-2,4,5,7,9,10-hexaoxatricyclo3,6>decane (2f) appreciable amounts of (3R,4S)-3-acetoxy-4-(benzoyloxy)-4-methyl-3-phenyl-1,2-dioxetane (3f) were detected.The bisdioxetanes 2 and monodioxetane 3f exhibited similar thermal stabilities, the free energies of activation (ΔG%) at 298 K falling within 25.5 + 1.5 kcal/mol.The singlet excitation yields (ΦS) ranged between 0.003 and 0.03percent and the triplet excitation yields (ΦT) between 9.5 and 71.5percent.Despite the favorable energy balance, it is concluded that no higher excited states of anhydride 4f are produced during the thermolysis of bisdioxetane 2f.On thermal activation, the bisdioxetanes decompose by sequential cleavage of the two dioxetane rings.
- Adam, Waldemar,Platsch, Herbert,Schmidt, Ernst
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p. 4385 - 4403
(2007/10/02)
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- REAGENTS AND SYNTHETIC METHODS 28. MODIFIED PROCEDURES FOR ANHYDRIZATION, ESTERIFICATION AND THIOLESTERIFICATION OF CARBOXYLIC ACIDS BY MEANS OF AVAILABLE PHOSPHORUS REAGENTS.
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Carboxylic acid anhydrides, esters and thiol esters are obtained by a one-pot method from carboxylic acids and alcohols or thiol by means of phosphorus oxychloride or phenyl dichlorophosphoridate reagents.
- Arrieta, A.,Garcia, T.,Lago, J. M.,Palomo, C.
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p. 471 - 488
(2007/10/02)
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- Palladium-promoted One-step Synthesis of Aromatic Acid Anhydrides from Aromatic Compounds with Carbon Monoxide
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The one-step synthesis of aromatic acid anhydrides from aromatic compounds such as benzene, toluene, anisole, chlorobenzene, furan, and thiophen has been carried out using carbon monoxide, 1,2-dibromoethane, and palladium acetate
- Fujiwara, Yuzo,Kawata, Itaru,Kawauchi, Tomio,Taniguchi, Hiroshi
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p. 132 - 133
(2007/10/02)
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