- 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)
-
- Organocatalytic Desymmetrisation of Fittig's Lactones: Deuterium as a Reporter Tag for Hidden Racemisation
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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)
-
- 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)
-
- 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)
-
- 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)
-
- One-pot synthesis of thioesters with sodium thiosulfate as a sulfur surrogate under transition metal-free conditions
-
In this paper, we report an efficient synthetic method for thioester formation from sodium thiosulfate pentahydrate, organic halides, and aryl anhydrides. In the one-pot two-step reactions developed in this study, sodium thiosulfate was used as the sulfur surrogate for acylation with anhydrides, followed by substitution with organic halides through the in situ generation of thioaroylate. Furthermore, two important organic compounds could be successfully synthesized using our developed method. The advantages of the one-pot two-step reactions are operational simplicity, structurally diverse products with 42%-90% yields, use of relatively low toxic and odourless reagents, and easy applicability to large-scale operation.
- Liao, Yen-Sen,Liang, Chien-Fu
-
supporting information
p. 1871 - 1881
(2018/03/23)
-
- Photocatalyic Appel reaction enabled by copper-based complexes in continuous flow
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A copper-based photocatalyst, Cu(tmp)(BINAP)BF4, was found to be active in a photoredox Appel-type conversion of alcohols to bromides. The catalyst was identified from a screening of 50 complexes and promoted the transformation of primary and secondary alcohols to their corresponding bromides and carboxylic acids to their anhydrides. The protocol was also amendable and optimized under continuous flow conditions.
- Minozzi, Clémentine,Grenier-Petel, Jean-Christophe,Parisien-Collette, Shawn,Collins, Shawn K.
-
supporting information
p. 2730 - 2736
(2018/11/21)
-
- 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)
-
- 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
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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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- TBHP/ n -Bu 4 PBr-Promoted Oxidative Cross-Dehydrogenative Coupling of Aryl Methanols: A Facile Synthesis of Symmetrical Carboxylic Anhydride Derivatives
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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)
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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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- 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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- Sc(OTf)3-catalyzed synthesis of anhydrides from twisted amides
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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
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p. 1780 - 1785
(2017/03/09)
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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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- TBHP-promoted and iodide-catalyzed synthesis of anhydrides via cross dehydrogenative coupling (CDC) of aldehydes
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We have successfully developed a transition metal free green methodology for the synthesis of carboxylic anhydrides from aldehydes via CDC pathway and have also demonstrated the reaction mechanism. The developed method has also been successfully applied for the synthesis of amides.
- Singha, Raju,Ghosh, Munmun,Nuree, Yasin,Ray, Jayanta K.
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supporting information
p. 1325 - 1327
(2018/03/29)
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- Cu(I) catalyzed synthesis of anhydrides from aldehydes via CDC-pathway at ambient temperature
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A one-pot simple and concise methodology has been developed for synthesizing aromatic carboxylic anhydrides starting from easily accessible aromatic aldehydes using cuprous chloride as the catalyst and TBHP as the oxidant in DMSO solvent to garner moderate to good yields via radical pathway in short and convenient reaction time at room temperature.
- Nuree, Yasin,Singha, Raju,Ghosh, Munmun,Roy, Pronay,Ray, Jayanta K.
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supporting information
p. 1479 - 1482
(2016/03/12)
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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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p. 566 - 569
(2016/01/20)
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- Metal-free cross-dehydrogenative coupling of aryl aldehydes to give symmetrical carboxylic anhydrides promoted by the TBHP/nBu4PBr system
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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
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supporting information
p. 3071 - 3074
(2016/07/06)
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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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- Light-enabled synthesis of anhydrides and amides
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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
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p. 2874 - 2878
(2015/03/30)
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- Palladium-catalyzed direct ortho aroylation of 2-phenoxypyridines with aldehydes and catalytic mechanism investigation
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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
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p. 953 - 966
(2015/03/18)
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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)
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- Synthesis of symmetric anhydrides using visible light-mediated photoredox catalysis
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A new approach to anhydride formation is reported via activation of C-O bonds by the Vilsmeier-Haack reagent formed by Ru(bpy)3Cl2 and CBr4 in DMF. Various aryl and alkyl carboxylic acids are converted to the corresponding anhydrides in excellent yields.
- Konieczynska, Marlena D.,Dai, Chunhui,Stephenson, Corey R. J.
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supporting information; experimental part
p. 4509 - 4511
(2012/07/31)
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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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scheme or table
p. 1320 - 1322
(2012/02/04)
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- Iron-doped single-walled carbon nanotubes as new heterogeneous and highly efficient catalyst for acylation of alcohols, phenols, carboxylic acids and amines under solvent-free conditions
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Iron-doped single-walled carbon nanotubes (Fe/SWCNTs) represent an efficient and new heterogeneous reusable catalyst for the acylation of a variety of alcohols, phenols, carboxylic acids and amines with acid chlorides or acid anhydrides under solvent-free conditions. The reactions of various primary, secondary, tertiary, and benzylic alcohols, diols, phenols, as well as aromatic and aliphatic amines give acylated adducts in good to excellent yields.
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi
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experimental part
p. 426 - 442
(2011/04/15)
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- Facile reaction of carboxylic acids with isonitriles in toluene
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Isonitriles react with low concentrations of carboxylic acids in toluene at 110 °C to give N-formylamides in yields generally above 70%. These concentrations can be obtained either by syringe pump addition of a toluene solution of the acid, or by using a suspension of the acid if it has limited solubility in toluene at room temperature.
- Polisar, Jason G.,Li, Ling,Norton, Jack R.
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p. 2933 - 2934
(2011/06/23)
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- Efficient and convenient synthesis of symmetrical carboxylic anhydrides from carboxylic acids with sulfated zirconia by phase transfer catalysis
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An efficient and convenient procedure for the synthesis of symmetrical carboxylic anhydrides from carboxylic acids with sulfated zirconia by PEG-1000 phase transfer catalysis has been developed. The reactions proceeded under mild and solvent-free conditions to provide the carboxylic anhydrides in good to excellent yields. The product can be isolated by a simple extraction with organic solvent, and the catalyst system can be recycled or reused without any significant loss of catalytic activity.
- Hu, Yu Lin,Zhao, Xing E.,Lu, Ming
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experimental part
p. 255 - 262
(2012/04/17)
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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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- 5H-3-oxa-Octafluoropentanesulfonyl fluoride: a novel and efficient condensing agent for esterification, amidation and anhydridization
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The use of 5H-3-oxa-octafluoropentanesulfonyl fluoride (HCF2CF2OCF2CF2SO2F) as a novel and efficient condensing reagent for esterification of carboxylic acids with alcohols and amidation of carboxylic acids with amines in the presence of 1,3-diazabicyclo[5.4.0]-undec-7-ene (DBU) is reported. HCF2CF2OCF2CF2SO2F cannot serve as a condensing agent for anhydridization of carboxylic acids, however, HCF2CF2OCF2CF2SO2F/(CH3)3SiCN system can mediate anhydridization of some aromatic carboxylic acids.
- Yan, Zhaohua,Tian, Weisheng,Zeng, Fanrong,Dai, Yanfeng
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experimental part
p. 2727 - 2729
(2009/09/06)
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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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- 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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- 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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- Investigation of the Yamaguchi esterification mechanism. Synthesis of a Lux-S enzyme inhibitor using an improved esterification method
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(Chemical Equation Presented) A one-pot procedure for the regioselective synthesis of aliphatic esters is described. This was a result of a study on mixed aliphatic-aromatic anhydrides. The data suggest that during the Yamaguchi esterification reaction, a symmetric aliphatic anhydride is produced in situ, which upon reaction with an alcohol yields the ester. We confirmed that benzoyl chloride could be used instead of the sterically hindered Yamaguchi acid chloride. This method was successfully applied in the synthesis of Lux-S aspartic acid inhibitor.
- Dhimitruka, Ilirian,SantaLucia Jr., John
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- Effects of flavonoids on cell proliferation and caspase activation in a human colonic cell line HT29: An SAR study
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A library of 42 natural and synthetic flavonoids has been screened for their effect on cell proliferation and apoptosis in a human colonic cell line (HT-29). Examples of different classes of flavonoids have been screened, and the effects of hydroxylation, methoxylation and/or C-alkylation at various positions in the A- and B-rings have been assessed. Flavones and flavonols possess greater antiproliferative activity than chalcones and flavanones. With respect to structural modification of flavonoids, C-isoprenylation was by far the most effective, with substitution at the 8-position and longer chains, such as geranyl giving the best results. Finally, most compounds that significantly reduced cell survival also increased caspase activity, suggesting that at least part of their antiproliferative activity might be attributable to an apoptotic response.
- Daskiewicz, Jean-Baptiste,Depeint, Flore,Viornery, Lionel,Bayet, Christine,Comte-Sarrazin, Geraldine,Comte, Gilles,Gee, Jennifer M.,Johnson, Ian T.,Ndjoko, Karine,Hostettmann, Kurt,Barron, Denis
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p. 2790 - 2804
(2007/10/03)
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- Substrate activity screening: A fragment-based method for the rapid identification of nonpeptidic protease inhibitors
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A new fragment-based method for the rapid development of novel and distinct classes of nonpeptidic protease inhibitors, Substrate Activity Screening (SAS), is described. This method consists of three steps: (1) a library of N-acyl aminocoumarins with diverse, low molecular weight N-acyl groups is screened to identify protease substrates using a simple fluorescence-based assay, (2) the identified N-acyl aminocoumarin substrates are optimized by rapid analogue synthesis and evaluation, and (3) the optimized substrates are converted to inhibitors by direct replacement of the aminocoumarin with known mechanism-based pharmacophores. The SAS method was successfully applied to the cysteine protease cathepsin S, which is implicated in autoimmune diseases. Multiple distinct classes of nonpeptidic substrates were identified upon screening an N-acyl aminocoumarin library. Two of the nonpeptidic substrate classes were optimized to substrates with >8000-fold improvements in cleavage efficiency for each class. Select nonpeptidic substrates were then directly converted to low molecular weight, novel aldehyde inhibitors with nanomolar affinity to cathepsin S. This study demonstrates the unique characteristics and merits of this first substrate-based method for the rapid identification and optimization of weak fragments and provides the framework for the development of completely nonpeptidic inhibitors to many different proteases.
- Wood, Warren J. L.,Patterson, Andrew W.,Tsuruoka, Hiroyuki,Jain, Rishi K.,Ellman, Jonathan A.
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p. 15521 - 15527
(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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- Mild and efficient synthesis of carboxylic acid anhydrides from carboxylic acids and triazine coupling reagents
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Anhydrides of carboxylic acids were obtained in 53%-95% yield by treatment of appropriate carboxylic acids with 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) or 2,4-dichloro-6-methoxy-1,3,5-triazine (DCMT) in the presence of N-methylmorpholine. It has been proved that synthesis proceeds via triazine active esters 3a,b, which are able to acylate carboxylate anion but not less nucleophilic carboxylic acid.
- Kaminski, Zbigniew J.,Kolesinska, Beata,Malgorzata, Marcinkowska
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p. 3349 - 3358
(2007/10/03)
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- Facile synthesis of carboxylic anhydrides using 4,5-dichloro-2-[(4-nitrophenyl)sulfonyl]pyridazin-3(2H)-one
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A novel and facile synthesis of carboxylic anhydrides from carboxylic acid using 4,5-dichloro-2-[(4-nitrophenyl)sulfonyl]pyridazin-3(2H)-one (2) is presented. Treatment of aliphatic or aromatic carboxylic acids with 2 in the presence of base in organic solvents gave the corresponding anhydrides in good or excellent yields.
- Kim, Jeum-Jong,Park, Yong-Dae,Song Lee, Woo,Cho, Su-Dong,Yoon, Yong-Jin
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p. 1517 - 1520
(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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- 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 convenient method for the synthesis and one-pot reaction of acyl chlorides using a scavenging resin
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A simple, efficient and fast method for the preparation of acyl halides from fatty carboxylic acids using a solid phase scavenging approach is presented herein. The title compounds can then be isolated, used as a solution or react in one-pot to form esters and amides with good to excellent yields.
- Girard,Tranchant,Niore,Herscovici
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p. 1577 - 1580
(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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- Acylpalladation of internal alkynes and palladium-catalyzed carbonylation of (Z)-β-iodoenones and related derivatives producing γ-lactones and γ-lactams
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The reaction of either an internal alkyne-organic halide mixture or (Z)-β-iodoenones with CO in the presence of a Pd-phosphine catalyst, e.g., Cl2Pd(PPh3)2, can give one of the three discrete types of compounds as the major products depending on the substrate structure and the reaction conditions. Those substrates which are convertible to (Z)-γ-oxo-α,β-unsaturated acylpalladium derivatives lacking δ-H atoms are converted to the corresponding 2-butenolides (13) in the presence of water, which serves as a H donor. Carbon monoxide most likely is the source of two electrons. Either in the absence of water (or any other suitable H source) or in the presence of some factors disfavoring the butenolide formation, the same reaction gives the corresponding dimeric product (16). Even in cases where there is an α-H atom in the α-substitutent, 1,4-elimination products (11), reported to be the major products in a related Pd-catalyzed reaction of terminal alkyne-aryl iodide mixtures with CO, were not detected. In sharp contrast, those substrates which can give rise to (Z)-γ-oxo-α,β-unsaturated acylpalladium derivatives containing δ-H atoms give, under comparable reaction conditions, enol lactones (12), i.e., (Z)-3-alkylidene-2-butenolides, contaminated with only very minor amounts of 22 even in cases where an excess (4 equiv) of water was present. The required (Z)-β-iodoenones can be readily prepared in one pot via ZrCp2-promoted cyclization of alkynes with nitriles. The ready availability of the starting compounds and the high Z stereoselectivity make the overall sequence an attractive synthetic route to 12. The courses of the Pd-catalyzed carbonylation reactions of (Z)-β-iodo-α,β-unsaturated imines 23 closely parallel the reactions of enones and produce the corresponding lactams, i.e., 24 and 25.
- Copéret, Christophe,Sugihara, Takumichi,Wu, Guangzhong,Shimoyama, Izumi,Negishi, Ei-Ichi
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p. 3422 - 3431
(2007/10/02)
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- COBALT(II) CHLORIDE CATALYZED SYNTHESES OF ACID ANHYDRIDES FROM ACID CHLORIDES
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Acid anhydrides were synthesized by reacting acid chlorides with carboxylic acids in the presence of catalytic quantities of cobalt(II) chloride.
- Srivastava, Rajiv R.,Kabalka, George W.
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p. 593 - 594
(2007/10/02)
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- A CONVENIENT PREPARATION OF CARBOXYLIC ACID ANHYDRIDES USING A "SUPPORTED" PHOSPHORUS PENTOXIDE REAGENT
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Treatment of carboxylic acids with a "supported" phosphorus pentoxide reagent provides a convenient route to the corresponding anhydrides.
- Burton, Stephanie G.,Kaye, Perry T.
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p. 3331 - 3336
(2007/10/02)
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- Hydroxy protection groups
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The present invention concerns a method for preparing unprotected hydroxy compounds or acylated derivatives thereof by conversion of silyl alkyl-protected hydroxy compounds. The invention also relates to novel intermediates useful in the method and for other purposes.
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- The Reaction of N-Carboalkoxy Reissert Analogs with Carboxylic Acids
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The reaction of N-carboalkoxy Reissert analogs in the presence of carboxylic acids yields the corresponding ester and heterocyclic base.Use of methoxy substituted benzoic acids yields, instead of the ester, the respective anhydride.Amides can also be prepared in a similar fashion.
- Popp, Frank D.,Duarte, Frederick F.,Uff, Barrie C.
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p. 1353 - 1355
(2007/10/02)
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