- Zinc mediated straightforward access to diacylpyrroles
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In this article, we report the preparation of various 2,4- and 2,5-diacylpyrroles via two zinc-mediated acylation reactions of non-protected pyrroles.
- Faye, Djiby,Mbaye, Mbaye Diagne,Coufourier, Sébastien,Lator, Alexis,Dieng, Samba Yandé,Gaillard, Sylvain,Renaud, Jean-Luc
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- A NEW ROUTE FOR MESO-SUBSTITUTED PORPHYRIN
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A new synthetic route of meso-substituted porphyrins was esthablished.The method presented here shows wide applicability for the preparation of aryl and alkyl meso-substituted porphyrins.
- Kuroda, Yasuhisa,Murase, Hiroaki,Suzuki, Yasuhiko,Ogoshi, Hisanobu
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- Kinetic studies on the 1,2-sigmatropic hydrogen shift in the photorearranged intermediate of N-acetylpyrrole: Tunneling effects
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The rates for the 1,2-sigmatropic hydrogen and deuterium shifts in the ground state of the photorearranged intermediate of N-acetylpyrrole were directly measured by means of laser flash photolysis in several solvents; (e.g., 0.27 s-1 for 1,2-H shift and 0.12 s-1 for 1,2-D shift in nonpolar methylcyclohexane (MCH) at 293 K). The rate of the 1,2-hydrogen shift was remarkably increased by a basic catalyst, such as triethylamine, alcohols, and water. From the experimental results of temperature and isotope effects, it was shown that the 1,2-sigmatropic hydrogen (or deuterium) shift in MCH proceeds via quantum mechanical tunneling processes at two vibrational energy levels: E = 0 (v = v0) and E = Ev (=2.9 kcal mol-1 for the hydrogen shift or 3.3 kcal mol-1 for the deuterium shift) (v = v1) under experimental conditions. The theoretical considerations for the tunneling mechanism were made by use of the tunnel effect theory proposed by Formosinho. The rates obtained by theoretical calculations were in good agreement with experimental ones. It is noteworthy that the 1,2-sigmatropic hydrogen (or deuterium) shift takes place via the intramolecular process at a low concentration of N-acetylpyrrole (1.7 × 10-4 M) in dehydrated MCH.
- Kimura, Yukihiro,Yamamoto, Masataka,Tobita, Seiji,Shizuka, Haruo
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- Non-acidic mediated friedel-craft reaction of thiophene using EtAlCl 2
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Since alkyl Lewis acids are Br?nsted bases, they give a non-acidic reaction media. In this context, acylation of thiophene is investigatedin the presence of EtAlCl2 and non-acidic media. Besides 8 examples of thiophene, one example for pyrrole is synthesized in moderate tohigh yields (up to 99 %).
- ünver, Halil,Biyikoglu, Mutluhan,Bulut, Adnan
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- Synthesis and properties of polyquinolines and polyanthrazolines containing pyrrole units in the main chain
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A series of eight new polyquinolines and polyanthrazolines with pyrrole isomeric units in main chain were synthesized and characterized. The new polymers showed high glass transition temperatures (Tg = 242-339°C) and excellent thermal stability (T5% = 398-536°C in air, TGA). Compared to the series of polyanthrazolines, the series of polyquinolines exhibited higher thermal stability, better solubility in common organic solvents, and lower maximum absorption wavelengths (λmaxa). Polyanthrazolines with 2,5-pyrrole linkage showed an unusually high λmaxa (565 nm) and small band gap (2.02 eV). All polymers in solution had low photoluminescence quantum yields between 10-2% and 10-5% and excited-state lifetimes of 0.28-1.29 ns. The effects of molecular structure, especially pyrrole linkage structures, on the electronic structure, thermodynamics, and some of the optical properties of the polymers were explored. A model of hydrogen bonds in the main chain of the polymers was suggested to explain the difference in the properties of the isomer polymers. In addition, a polyquinoline (PBM) was chosen to examine the proton conductivity; the result indicated that the PBM/H3PO4 complex exhibited a high conductivity of 1.5 × 10-3 S cm-1 at 157°C. The new polymers are expected to have improved proton-conducting properties for the application as the membranes in fuel cells.
- Hou, Shifa,Ding, Mengxian,Gao, Lianxun
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- Efficient microwave-assisted syntheses of a series of novel mono(Imino)Pyrrolyl compounds
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A series of novel mono(imino)pyrroles that were hard to prepare under traditional solvent reaction condition were readily synthesized under solvent free condition using microwave chemistry via p-TSA (p-toluenesulfonic acid) catalyzed Schiff base condensation. The structures of the compounds were characterized by means of MS, 1H NMR, IR, elementary analysis and X-ray diffraction analysis. The reactivity of different aromatic amines with 2-acetylpyrrole was discussed.
- Su, Biyun,Li, Xiaoteng,Wang, Xudong,Li, Qianding
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- 1,2-Dioximes in the Trofimov reaction
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3,3′-Dimethyl-1,1′-divinyl-2,2′-dipyrrole was obtained during the reaction of 3,4-hexanedione dioximes with acetylene under pressure in the potassium hydroxide-DMSO system. In the case of 1,2-cyclohexanedione dioxime 2,2′-dipyrrole and 2-pyridyl- and 2-acylpyrroles were isolated. α-Benzil and α-furil dioximes give 3,4-diphenyl- and 3,4-di(2-furyl)-1,2,5-oxadiazoles respectively in addition to their mono- and divinyl derivatives. 2006 Springer Science+Business Media, Inc.
- Zaitsev,Schmidt,Vasil'tsov,Mikhaleva,Petrova,Afonin,Zorina
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- Entropic Mixing Allows Monomeric-Like Absorption in Neat BODIPY Films
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Intermolecular interactions play a crucial role in materials chemistry because they govern thin film morphology. The photophysical properties of films of organic dyes are highly sensitive to the local environment, and a considerable effort has therefore been dedicated to engineering the morphology of organic thin films. Solubilizing side chains can successfully spatially separate chromophores, reducing detrimental intermolecular interactions. However, this strategy is also significantly decreasing achievable dye concentration. Here, five BODIPY derivatives containing small alkyl chains in the α-position were synthesized and photophysically characterized. By blending two or more derivatives, the increase in entropy reduces aggregation and therefore produces films with extreme dye concentration and, at the same time almost solution like absorption properties. Such a film was placed inside an optical cavity and the achieved system was demonstrated to reach the strong exciton-photon coupling regime by virtue of the achieved dye concentration and sharp absorption features of the film.
- Sch?fer, Clara,Mony, Jürgen,Olsson, Thomas,B?rjesson, Karl
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- Photo-on-Demand Synthesis of Vilsmeier Reagents with Chloroform and Their Applications to One-Pot Organic Syntheses
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The Vilsmeier reagent (VR), first reported a century ago, is a versatile reagent in a variety of organic reactions. It is used extensively in formylation reactions. However, the synthesis of VR generally requires highly toxic and corrosive reagents such as POCl3, SOCl2, or COCl2. In this study, we found that VR is readily obtained from a CHCl3 solution containing N,N-dimethylformamide or N,N-dimethylacetamide upon photo-irradiation under O2 bubbling. The corresponding Vilsmeier reagents were obtained in high yields with the generation of gaseous HCl and CO2 as byproducts to allow their isolations as crystalline solid products amenable to analysis by X-ray crystallography. With the advantage of using CHCl3, which bifunctionally serves as a reactant and a solvent, this photo-on-demand VR synthesis is available for one-pot syntheses of aldehydes, acid chlorides, formates, ketones, esters, and amides.
- Liang, Fengying,Eda, Kazuo,Okazoe, Takashi,Wada, Akihiro,Mori, Nobuaki,Konishi, Katsuhiko,Tsuda, Akihiko
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p. 6504 - 6517
(2021/05/06)
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- Visible light mediated selective oxidation of alcohols and oxidative dehydrogenation of N-heterocycles using scalable and reusable La-doped NiWO4nanoparticles
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Visible light-mediated selective and efficient oxidation of various primary/secondary benzyl alcohols to aldehydes/ketones and oxidative dehydrogenation (ODH) of partially saturated heterocycles using a scalable and reusable heterogeneous photoredox catalyst in aqueous medium are described. A systematic study led to a selective synthesis of aldehydes under an argon atmosphere while the ODH of partially saturated heterocycles under an oxygen atmosphere resulted in very good to excellent yields. The methodology is atom economical and exhibits excellent tolerance towards various functional groups, and broad substrate scope. Furthermore, a one-pot procedure was developed for the sequential oxidation of benzyl alcohols and heteroaryl carbinols followed by the Pictet-Spengler cyclization and then aromatization to obtain the β-carbolines in high isolated yields. This methodology was found to be suitable for scale up and reusability. To the best of our knowledge, this is the first report on the oxidation of structurally diverse aryl carbinols and ODH of partially saturated N-heterocycles using a recyclable and heterogeneous photoredox catalyst under environmentally friendly conditions.
- Abinaya, R.,Balasubramaniam, K. K.,Baskar, B.,Divya, P.,Mani Rahulan, K.,Rahman, Abdul,Sridhar, R.,Srinath, S.
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p. 5990 - 6007
(2021/08/24)
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- Neutrophil-Selective Fluorescent Probe Development through Metabolism-Oriented Live-Cell Distinction
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Human neutrophils are the most abundant leukocytes and have been considered as the first line of defence in the innate immune system. Selective imaging of live neutrophils will facilitate the in situ study of neutrophils in infection or inflammation events as well as clinical diagnosis. However, small-molecule-based probes for the discrimination of live neutrophils among different granulocytes in human blood have yet to be reported. Herein, we report the first fluorescent probe NeutropG for the specific distinction and imaging of active neutrophils. The selective staining mechanism of NeutropG is elucidated as metabolism-oriented live-cell distinction (MOLD) through lipid droplet biogenesis with the help of ACSL and DGAT. Finally, NeutropG is applied to accurately quantify neutrophil levels in fresh blood samples by showing a high correlation with the current clinical method.
- Gao, Min,Lee, Sun Hyeok,Park, Sang Hyuk,Ciaramicoli, Larissa Miasiro,Kwon, Haw-Young,Cho, Heewon,Jeong, Joseph,Chang, Young-Tae
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supporting information
p. 23743 - 23749
(2021/10/14)
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- A preparing method of 1-ethyl-2-acetylpyrrole
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A preparing method of 1-ethyl-2-acetylpyrrole is disclosed. Pyrrole is adopted as an initial raw material and is subjected to two reaction steps to prepare the 1-ethyl-2-acetylpyrrole. Firstly, 2-acetylpyrrole is prepared from the pyrrole, N,N-dimethylacetamide, 1,2-dichloroethane and phosphorus oxychloride; and then the 1-ethyl-2-acetylpyrrole is prepared from KOH, water, trimethylstearylammoniumchloride, the 2-acetylpyrrole and diethyl carbonate. Beneficial effects of the method are that the method is safe and environment-friendly, a process is simple to operate and feasible, a finished product is high in content, raw materials are easily available, a production cost is low, and the method is suitable for large-scale production.
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Paragraph 0008; 0010
(2018/04/21)
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- Metal-Free Intermolecular Coupling of Arenes with Secondary Amides: Chemoselective Synthesis of Aromatic Ketimines and Ketones, and N-Deacylation of Secondary Amides
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The direct transformation of common secondary amides into aromatic ketimines and aromatic ketones with C-C bond formation is described. The reaction can also be used for N-deacylation of secondary amides to release amines. This method consists of in situ amide activation with triflic anhydride and intermolecular capture of the resulting highly electrophilic nitrilium intermediate with an arene. The reaction is applicable to various kinds of secondary amides (electrophiles), but only electron-rich and moderately electron-rich arenes can be used as nucleophiles. Thanks to the use of bench stable arenes instead of reactive and basic organometallics as nucleophiles, the reaction proceeded with high chemoselectivity at the secondary amido group in the presence of a series of sensitive functional groups such as aldehyde, ketone, ester, cyano, nitro, and tertiary amido groups. The reaction can be viewed as a Friedel-Crafts-type reaction using secondary amides as acylating agents or as an intermolecular version of the Bischler-Napieralski reaction.
- Huang, Pei-Qiang,Huang, Ying-Hong,Xiao, Kai-Jiong
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p. 9020 - 9027
(2016/10/17)
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- Reactions of nitrilium salts with indole and pyrrole and their derivatives in the synthesis of imines, ketones and secondary amines
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Abstract Reactions of N-methyl- and N-ethyl-nitrilium salts with indole and pyrrole and their derivatives yield imines or imine salts in good yields. The related imines are obtained from the salts after careful basification and hydrolysis of the imine salts or the imines by heating with aqueous base give the related ketones in good yields. Alternatively, the imine salts can be reduced using sodium borohydride in methanol to give the related secondary amines.
- Giles, Robert G.,Heaney, Harry,Plater, M. John
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p. 7367 - 7385
(2015/08/24)
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- Synthesis of industrially important aromatic and heterocyclic ketones using hierarchical ZSM-5 and Beta zeolites
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Hierarchical ZSM-5 and Beta zeolites were investigated in the synthesis of wide range of industrially important aromatic/heterocyclic ketones by Friedel-Crafts acylation and benzoylation reactions. For comparative study, conventional ZSM-5 and Beta, and amorphous mesoporous Al-MCM-41 were investigated. Hierarchical zeolites were prepared by multi-ammonium structure directing agents whereas conventional zeolites were prepared by mono-ammonium structure directing agents. Among the catalysts investigated in this study, hierarchical Beta exhibited the highest reactant conversion in the acylation and benzoylation reactions. In this study, the systematic assessment of the catalytic activity of acid catalysts for wide range of aromatic and heterocyclic compounds is shown under one umbrella. To the best of our knowledge, these reactions over hierarchical zeolites (ZSM-5 and Beta) are reported here for the first time. Structure activity relationship is explained based on the physico-chemical properties, molecular size, reactivity of reactants, and reaction mechanism. Catalysts can be easily recovered and reused with negligible loss in the catalytic activity.
- Kore, Rajkumar,Srivastava, Rajendra,Satpati, Biswarup
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p. 129 - 141
(2015/09/28)
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- Gold-catalyzed oxime-oxime rearrangement
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The gold-catalyzed reaction of pyrrole and indole oximes having a propargyl group attached to the nitrogen atom was studied. The selective 6-endo-dig mode of cyclization was observed for the terminal alkynes giving rise to the formation of pyrazine N-oxides in the presence of a gold catalyst. However, the reaction with substituted alkyne transferred the oxime functionality intramolecularly from one carbon atom to another via the 7-endo-dig cyclization process. This transformation is unprecedented in the literature and is named an oxime-oxime rearrangement.
- Guven, Sinem,Ozer, Merve Sinem,Kaya, Serdal,Menges, Nurettin,Balci, Metin
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supporting information
p. 2660 - 2663
(2015/06/16)
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- Solvent free synthesis of 2-acylpyrroles and its derivatives catalysed by reuseable zinc oxide
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A highly efficient procedure for preparing 2-acylpyrroles and its derivatives is described. The products were obtained through regioselective Friedel-Crafts reactions of pyrroles and its derivatives with alkyl or aryl acid chlorides catalysed by zinc oxide under solvent-free conditions. This method has the advantages of green chemistry, operational simplicity, solvent-free conditions, and recoverable catalyst.
- Zhang, Shuguang,Feng, Chengliang,Cai, Jin,Chen, Junqing,Hu, Huayou,Ji, Min
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p. 480 - 482
(2013/09/12)
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- Synthesis and in vitro antitumor activity of 1-(3-dimethylamino)propyl indolin-2-one derivatives
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A series of 1-(3-dimethylaminopropyl)indolin-2-one derivatives were designed and synthesized based on the structural features of TMP-20, LK-B030, and BX-517. These newly synthesized derivatives were evaluated for in vitro activity against five human cancer cell lines and three HUVECs. Results revealed that all of the target compounds 1a-h generally show potent activity against these cancer cell lines and higher selectivity on VEGF- and bFGF-stimulated HUVECs than HUVEC. In particular, 1f (IC50s: 1.10-1.47 μM) is 1.8-6.0-fold more potent than sunitinib against MDA-MB-231, A549, HL-60 and K-562, and 1.6-2.8-fold more potent than LK-B030 against MDA-MB-231 and A549.
- Lv, Kai,Wang, Li-Li,Zhou, Xin-Bo,Liu, Ming-Liang,Liu, Hong-Ying,Zheng, Zhi-Bing,Li, Song
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p. 1723 - 1729
(2013/07/26)
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- Efficient and recyclable rare earth-based catalysts for Friedel-Crafts acylations under microwave heating: Dendrimers show the way
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The catalytic system involving Sc(OTf)3 and a dendritic terpyridine ligand is able to promote the Friedel-Crafts acylation of a wide range of aromatics under microwave irradiation. The expected products are obtained in high yields after short reaction times and the nano-sized catalyst can be recovered and successfully used in 12 consecutive runs.
- Perrier, Arnaud,Keller, Michel,Caminade, Anne-Marie,Majoral, Jean-Pierre,Ouali, Armelle
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supporting information
p. 2075 - 2080
(2013/09/24)
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- Design and synthesis of pyrrolotriazepine derivatives: An experimental and computational study
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The pyrrole derivatives having carbonyl groups at the C-2 position were converted to N-propargyl pyrroles. The reaction of those compounds with hydrazine monohydrate resulted in the formation of 5H-pyrrolo[2,1-d][1,2,5] triazepine derivatives. The synthesis of these compounds was accomplished in three steps starting from pyrrole. On the other hand, attempted cyclization of a pyrrole ester substituted with a propargyl group at the nitrogen atom gave, unexpectedly, the six-membered cyclization product, 2-amino-3-methylpyrrolo[1,2- a]pyrazin-1(2H)-one as the major product. The expected cyclization product with a seven-membered ring, 4-methyl-2,3-dihydro-1H-pyrrolo[2,1-d][1,2,5]triazepin-1- one was formed as the minor product and was converted quantitatively to the major product. The formation mechanism of the products was investigated, and the results obtained were also supported by theoretical calculations.
- Menges, Nurettin,Sari, Ozlem,Abdullayev, Yusif,Erdem, Safiye Sag,Balci, Metin
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p. 5184 - 5195
(2013/07/25)
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- Friedel-Crafts acylation of pyrrole over ultrasonic-assisted phosphoric acid-modified Hβ zeolite
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Friedel-Crafts acylation of pyrrole with acetic anhydride was studied over different zeolites and an ultrasonic-assisted phosphoric acid-modified Hβ (P-Hβ-US) zeolite was found to have the best catalytic performance among all the zeolites examined. The conversion of acetic anhydride reached 98.8% and the selectivity to acetylpyrroles was 97.0% under the optimized conditions. The high activity of the P-Hβ-US zeolite is attributed to the increase of weak acid sites, caused by the synergistic effect between the phosphoric acid modification and ultrasound. Moreover, the carbonaceous deposits, mainly due to the adsorption of reactants and products, on the surface acid sites and the blockage of the pores is believed to be the reason for the deactivation of the reused P-Hβ-US zeolite, confirmed from the Brunauer-Emmett-Teller (BET) method, scanning electron microscopy, and X-ray photoelectron spectroscopy. Furthermore, the catalyst activity can be recovered effectively by a subsequent calcination. Springer Science+Business Media B.V. 2011.
- Bai, Guo Yi,Yang, Yong Hui,Ma, Zheng,Xu, Jian Zhong,Qiu, Man De,He, Fei,Yan, Xi Long,Dou, Hai Yang
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experimental part
p. 795 - 806
(2012/08/28)
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- Volatile compounds formed from the pyrolysis of chitosan
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Chitosan is a renewable resource for the production of nitrogen-containing aromatic heterocyclics. It was found that chitosan started to decompose and produce some volatile compounds at around 525 K in a nitrogen atmosphere, the volatiles were characterized by Fourier transform infrared spectrometer. The apparent activation energy for the thermal degradation of chitosan was determined. To further investigate the degradation, chitosan was pyrolyzed under vacuum at 553 K for 1 h, and the volatile compounds were analyzed by gas chromatography/mass spectrometry. The volatile compounds included aromatic heterocyclics such as pyrazines, pyridines, pyrroles and furans, and the pyrazines were the major products. The pyrolysis mechanism of chitosan was also proposed.
- Zeng, Lintao,Qin, Caiqin,Wang, Liansheng,Li, Wei
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experimental part
p. 1553 - 1557
(2011/09/14)
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- Friedel-crafts acylation of arenes with carboxylic acids using polystyrene-supported aluminum triflate
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Cross-linked polystyrene-supported aluminum triflate (Ps-Al(OTf) 3) has been shown to be a mild, efficient, and chemoselective heterogeneous Lewis acid catalyst for the acylation of aromatic compounds. The catalyst can be easily prepared from cheap starting materials, is stable (as a bench top catalyst) and is reusable.
- Boroujeni, Kaveh Parvanak,Parvanak, Kamran
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experimental part
p. 155 - 163
(2012/01/02)
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- Nano-sulfated titania (TiO2/SO2-4) as a new solid acid catalyst for Friedel-Crafts acylation and Beckman rearrangement in solvent-free conditions
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The present work describes a novel application of nano-sulfated titania (nano-ST) as a solid acid catalyst for Friedel-Crafts acylation and Beckmann rearrangement. A nano-ST catalyst has been synthesized and characterized using various techniques such as XRD, scanning electron morphology, transmission electron microscopy, FT-IR, measurement of the specific surface area by Brunauer-Emmett-Teller theory and thermal analysis. The influences of various reaction parameters such as reaction temperature, molar ratio of reactants, reaction time and solvent effects have been investigated. [image omitted].
- Hosseini-Sarvari, Mona,Safary, Ensieh
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experimental part
p. 463 - 473
(2012/06/16)
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- Investigation of the aroma-active compounds formed in the maillard reaction between glutathione and reducing sugars
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Aroma-active compounds formed during the thermal reaction between glutathione (GSH) and reducing sugars were analyzed by gas chromatography-mass spectrometry (GC-MS) and GC-olfactometry (GC-O) with aroma extract dilution analysis (AEDA). Application of AEDA to glutathione Maillard reaction products (GSH MRPs) led to the identification of 19 aroma-active compounds in the thermal reaction of glutathione with glucose or fructose. In addition, the carbohydrate module labeling (CAMOLA) approach was also employed to elucidate the formation pathways for selected target sulfur aroma compounds, such as 5-methylthiophene-2-carbaldehyde and 3-methylthiophene-2-carbaldehyde, which have not been reported previously. The intact carbon skeleton of glucose via 3-deoxyhexosone is incorporated into 5-methylthiophene-2-carbaldehyde with the hydrogen sulfide of GSH. On the other hand, the formation of 3-methylthiophene2-carbaldehyde may occur via the recombination of a C-4 sugar fragment and mercaptoacetaldehyde.
- Lee, Sang Mi,Jo, Ye-Jin,Kim, Young-Suk
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experimental part
p. 3116 - 3124
(2011/08/05)
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- A new and highly efficient water-soluble copper complex for the oxidation of secondary 1-heteroaryl alcohols by tert-butyl hydroperoxide
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The water-soluble copper complex generated in situ from CuCl2 and 2,2′-biquinoline-4,4′-dicarboxylic acid dipotassium salt (BQC), has been revealed as a highly efficient and selective catalyst for the oxidation of secondary 1-heteroaryl alcohols to the corresponding heteroaromatic ketones with aqueous tert-butyl hydroperoxide, under mild conditions. The catalytic system is compatible with different heterocycles such as pyridines, pyrroles, indoles, thiophens, furans, thiazoles, and imidazoles.
- Boudreau, Josée,Doucette, Mike,Ajjou, Abdelaziz Nait
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p. 1695 - 1698
(2007/10/03)
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- From ligand to complexes: Inhibition of human immunodeficiency virus type 1 integrase by β-diketo acid metal complexes
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β-Diketo acid-containing compounds are a promising class of human immunodeficiency virus type 1 (HIV-1) integrase (IN) inhibitors. Starting from the hypothesis that these inhibitors are able to coordinate ions in solution before interacting on the active site, a series of potentiometric measurements have been performed to understand the coordination ability of the diketo acid pharmacophore toward the biologically relevant Mg2+. Moreover, by using β-diketo acid/ester as model ligands with a set of divalent metal ions (Mg, Mn, Ni, Co, Cu, and Zn), we obtained a series of complexes and tested them for anti-HIV-1 IN activity. Results demonstrate that the diketo acid functionality chelates divalent metal ions in solution, and complexes with metals in different stoichiometric ratios are isolated. We postulate that the diketo acids act as complexes in their active form. In particular, they predominantly form species such as Mg2L2+ and Mg 2L2 (derived from diketo acids, H2L), and MgL+ and MgL2 (derived from diketo esters, HL) at physiological pH. Furthermore, the synthesized mono- and dimetallic complexes inhibited IN at a high nanomolar to low micromolar range, with metal dependency in the phenyl diketo acid series. Retrospective analysis suggests that the electronic properties of the aromatic framework influence the metal-chelating ability of the diketo acid system. Therefore, the difference in activities is related to the complexes they preferentially form in solution, and these findings are important for the design of a new generation of IN inhibitors.
- Sechi, Mario,Bacchi, Alessia,Carcelli, Mauro,Compari, Carlotta,Duce, Elenia,Fisicaro, Emilia,Rogolino, Dominga,Gates, Paul,Derudas, Marco,Al-Mawsawi, Laith Q.,Neamati, Nouri
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p. 4248 - 4260
(2007/10/03)
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- Vilsmeier-Haack preparation of 2-acylpyrroles using bis(trichloromethyl) carbonate and N,N-dimethylacylamines
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A series of 2-acylpyrroles were synthesized by using bis(trichloromethyl) carbonate and N,N-dimethylacylamines as Vilsmeier-Haack reagents under mild conditions in good yields.
- Shi,Su,Shan
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p. 1019 - 1021
(2007/10/03)
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- Aluminum dodecatungstophosphate (AlPW12O40) as a non-hygroscopic Lewis acid catalyst for the efficient Friedel-Crafts acylation of aromatic compounds under solvent-less conditions
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Stable and non-hygroscopic aluminum dodecatungstophosphate (AlPW 12O40), which is prepared easily from cheap and commercially available compounds was found to be an effective catalyst for Friedel-Crafts acylation reactions using carboxylic acids, acetic anhydride and benzoyl chloride in the absence of solvent under mild reaction conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Nowrouzi, Farhad
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p. 10843 - 10850
(2007/10/03)
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- Antipicornaviral compounds and compositions, their pharmaceutical uses, and materials for their synthesis
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Compounds of the formula: where the formula variables are as defined in the disclosure, advantageously inhibit or block the biological activity of the picomaviral 3C protease. These compounds, as well as pharmaceutical compositions containing these compounds, are useful for treating patients or hosts infected with one or more picomaviruses, such as RVP. Intermediates and synthetic methods for preparing such compounds are also described.
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- Zinc-mediated acylation and sulfonation of pyrrole and its derivatives
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Pyrrole and its derivatives react smoothly with acid chlorides and sulfonyl chlorides in the presence of zinc metal in toluene at ambient temperature to afford the corresponding 2-acetyl and 2-sulfonyl pyrrole derivatives in high yields with high regioselectivity.
- Yadav,Reddy,Kondaji,Srinivasa Rao,Praveen Kumar
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p. 8133 - 8135
(2007/10/03)
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- Diethoxymethyl protected pyrroles: Synthesis and regioselective transformations
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Treatment of the acceptor-substituted pyrroles 1a-k with neat triethyl orthoformate gives access to the diethoxymethyl (DEM) protected derivatives 2a-k in high yield. Convenient and mild cleavage was achieved by subsequent treatment of the DEM-pyrroles 2a-k with trifluoroacetic acid in acetonitrile and aqueous NaOH at room temperature. DEM protection proved suitable for a variety of regioselective transformations involving directed orthometalation and iodine-magnesium exchange processes. Furthermore, electrophilic halogenations and Pd-catalyzed coupling reactions were also carried out.
- Bergauer,Gmeiner
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p. 2281 - 2288
(2007/10/03)
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- Synthesis of some diethylphosphono substituted 3H-pyrrolizines
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The preparation of various alkyl substituted monophosphonate 3H-pynolizines via a tandem Michael □ Horner-Emmons reaction is reported. These products were prepared from tetraethyl ethylidene gem-bisphosphonate and corresponding 2-acylpyrroles.
- Loussouarn,Servant,Guervenou,Sturtz
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p. 275 - 285
(2007/10/03)
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- Oxidative radical cyclization to pyrroles under reducing conditions. Reductive desulfonylation of α-sulfonylpyrroles with tri-n-butyltin hydride
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1-(2-Bromobenzyl)-2-alkanesulfonylpyrroles (1c, 1d) and 1-(4-bromobutyl)-2-methylsulfonylpyrrols (8) undergo oxidative radical cyclization with partial or complete reductive desulfonylation to the pyrrolizidine derivatives 5 and 9 by an AIBN initiated reaction with tri-n-butyltin hydride.These cyclizations are suggested to proceed via a pseudo SRN1 process involving radical addition to the α position of the pyrrole nucleus not bearing the sulfonyl group.Reductive removal of the alkylsulfonyl moiety is proposed to occur in a second process after completion of the oxidative radical cyclization.The site of the radical addition is supported by deuterium labelling studies.Consistent with the timing of the loss of the sulfonyl group is that 2-alkylsulfonylpyrroles 11 are reductively desulfonylated under the same conditions that effect the oxidative radical cyclizations.
- Antonio, Yulia,Cruz, Ma. Elizabeth De La,Galeazzi, Edvige,Guzman, Angel,Bray, Brian L.,et al.
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- Gas-phase heteroaromatic substitution. 11. Electron transfer mechanism in the gas-phase acylation of simple five-membered heteroarenes
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The results of a study of the gas-phase reactions of unsaturated carbocations, such as the CH3CO+ ion from γ-radiolysis of CH3F/CO mixtures, and the C6H4TCO+ ion from the β-decay of 1,4-ditritiobenzene in the presence of CO, with pyrrole, N-methylpyrrole, furan, and thiophene, are reported.In all systems investigated, acylated heteroarenes represent the predominant reaction products, accompanied by the methylated derivatives in the CH3F/CO radiolytic mixtures, and by the phenylated ones in the 1,4-ditritiobenzene/CO decay samples.All substrates investigated are found to undergo predominat α substitution by both acetyl (88.6-98.4percent (pyrrole); 90.8-98.7percent (N-methylpyrrole); 97.2-98.9percent (furan); 94.9-98.6percent (thiophene)) and benzoyl cations (92.6-96.5percent (pyrrole)) under all conditions.The predominant formation of the α-acylated pyrroles from both reactants (>88percent), whose relative yields appear unaffected within the temperature interval from 303 to 383 K, indicates, in agreement with ancillary FT-ICR mass spectrometric evidence, that gas-phase acylation reactions toward simple five-membered heteroarenes proceed via a two-step substitution mechanism, involving a quasi-resonant single-electron transfer (SET) step followed by recombination of the ensuing radical - radical ion pair.By virtue of this entropy-favored mechanism, gaseous electrophiles with relatively high SCF STO-3G calculated LUMO energies such CH3CO+ and C6H4TCO+ are effectively oriented toward the "soft" Cα sites of the selected heteroarenes, at variance with Klopman's Charge and Frontier Orbital Control predictions.The behavior of gaseous acylating reactants toward simple heteroarenes is discussed and compared with that of other gaseous electrophiles, whose reactivity appears instead in qualitative agreement with Klopman's model.
- Filippi, Antonello,Occhiucci, Giorgio,Sparapani, Cinzia
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p. 740 - 748
(2007/10/02)
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- 2-SUBSTITUTED 1,3-BENZODITHIOLIUM TETRAFLUOROBORATES AS USEFUL ACYLATING AGENTS OF PYRROLE
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A comparative study on the acylation of pyrrole by utilizing 2-substituted 1,3-benzodithiolium tetrafluoroborates instead of 2-substituted 1,3-benzoxathiolium tetrafluoroborates has been accomplished.The use of 2-substituted 1,3-benzodithiolium tetrafluoroborates proved to be more convenient since it gives higher yields of 2-acylpyrroles (58-90percent) and appears of larger applicability for the preparation of symmetrical and unsymmetrical 2,5-diacylpyrroles which were obtained in most cases in quantitative yields.
- Barbero, Margherita,Cadamuro, Silvano,Degani, Iacopo,Dughera, Stefano,Fochi, Rita,et al.
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p. 619 - 627
(2007/10/02)
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- First Reactions of Dialkoxycarbenium Tetrafluoroborates with Pyrroles, 5H-Dibenzazepines, and Electron-Rich Arenes
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Pyrrole (2a) and 2,5-dimethylpyrrole (2b) react with the dialkoxycarbenium tetrafluoroborates 1a-1c under kinetic control to yield the corresponding acylpyrrole derivatives. 5H-Dibenzazepine (9a) and the 10,11-dihydro derivative 9b react only with the most elecrophilic of the series of electrophiles tested, namely, diethoxycarbenium tetrafluoroborate (1a), to furnish the corresponding formyl derivatives.Similarly, in arene chemistry, the highly electron-rich N,N-dimethylaniline (13a) and 1,3,5-trimethoxybenzene (13b) are formylated by reaction with 1a.
- Pindur, U.,Flo, C.
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p. 1563 - 1568
(2007/10/02)
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- Acylation of Pyrrole and N-Methylpyrrole with 1,3-Benzoxathiolium Tetrafluroborates. A High-Yield Method for the Synthesis of Diacylpyrroles
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2-Substituted 1,3-benzoxathiolium tetrafluoroborates (I) were used as masked acylating agents for pyrrole and N-methylpyrrole.The reactions on pyrrole (II) were regiospecific, and according to the molar ratio of the reagents (I:II = 1:3 or 2.5-3:1), 2-acylpyrroles were obtained in moderate to good yields (38-82percent) and 2,5-diacylpyrroles were obtained in excellent yields (in most cases, quantitative).The reactions on N-methylpyrrole (III) were not regioselective, and both α- and β-positions were attacked.So, depending on the molar ratio of the reagents (I:III = 1:3 or 2,5-3:1), 2- and 3-acyl-N-methylpyrroles (9-51percent and 27-68percent yields, respectively) and 2,4- and 2,5-diacyl-N-methylpyrroles (60-93percent and 17-40percent, respectively) were obtained.A very interesting feature of the new method is the possibility of introducing two identical or different acyl groups in the pyrrole ring under mild conditions. 1H and 13C NMR spectra of all the new compounds and IR spectra, recorded in the gas phase, of 2- and 3-acylpyrroles and of 2,4- and 2,5-diacylpyrroles are reported.
- Barbero, Margherita,Cadamuro, Silvano,Degani, Iacopo,Fochi, Rita,Gatti, Antonella,Regondi, Valeria
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p. 2245 - 2250
(2007/10/02)
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- Maillard Reaction Products Formed from D-Glucose and Glycine and the Formation Mechanisms of Amides as Major Components
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Equimolar aqueous solution of D-glucose and glycine were heated at 50 oC and 95 oC at pH 6.7.The headspace volatiles and the ether extracts from the reaction mixture were analyzed by gaz chromatography and gas chromatography-mass spectrometry, using a fused silica capillary column.The major components formed were identified as diacetyl, furfuryl alcohol, two pyrroles, one pyranone and two amides.In order to elucidate the formation mechanisms of the amides formed from amino-carbonyl reactions, two model systems were adopted.N-Butylacetamide and N-butylformamide were formed as major components from diacetyl-butylamine and glyoxal- butylamine systems, respectively.The results obtained suggest that such α-dicarbonyls as 3-deoxyosone, 1-deoxy-D-erythro-2,3-hexodiulose and diacetyl generated in the amino-carbonyl reaction react with amino compounds, amides then formed by cleavage of the C-C bond in the α-dicarbonyls.
- Hayase, Fumikata,Kim, Bong Seon,Kato, Hiromichi
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p. 2337 - 2342
(2007/10/02)
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- Pyrrole chemistry. XXVIII. Substitution reactions of 1-(phenylsulfonyl)pyrrole and some derivatives
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The preparative value of the 1-(phenylsulfonyl) N-blocking and directing group for the synthesis of 3-acylpyrroles has been further evaluated.Acetylation and benzoylation are strongly regiospecific and give good yields.However, the regiospecificity is not general and other substitution reactions give mixtures of 2- and 3-substitution or even mostly 2-substitution.Friedel and Crafts tert-butylation gives 3-tert-butyl-1-(phenylsulfonyl)pyrrole and provides a useful route to tert-butylpyrrole, but ethylation and isopropylation give mixtures.Acylations of 2- and 3-alkyl-1-(phenylsulfonyl)pyrroles show little evidence of useful regiospecificity.
- Anderson, Hugh J.,Loader, Charles E.,Xu, Ru Xun,Le, Nghia,Gogan, Niall J.,et al.
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p. 896 - 902
(2007/10/02)
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- THE FORMATION OF ACYLAMINO-DERIVATIVES OF INDOLES AND PYRROLES BY REACTIONS WITH NITRILIUM SALTS
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N-Methylnitrilum fluoroborates are prepared rapidly by warming trimethyloxonium fluoroborate wiht a slight excess of the nitrile, subsquent addition of indoles and pyrroles at low temperatures (-50 deg C to -20 deg C) gives iminium salts (and hence ketones) in high yields.
- Eyley, Stephen C.,Giles, Robert G.,Heaney, Harry
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p. 4649 - 4652
(2007/10/02)
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- Intramolecular Thermal Oxidoreduction of N-(2-Hydroxypropyl)-β-enaminoesters: Synthesis of N-(Acetonyl)-β-enaminoaldehydes and 2-Acetylpyrroles
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Flow pyrolysis of the β-enaminoesters (1) provides the enaminoaldehydes (2), resulting from intramolecular oxidoreduction, and the acetylpyrroles (3); their relative yields depend on the temperature range.
- Maujean, Alain,Grosdemange-Pale, Catherine,Marcy, Guy,Chuche, Josselin
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p. 1135 - 1136
(2007/10/02)
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- On the Formation of 2-Acylpyrroles and 3-Pyridinols in the Maillard Reaction through Strecker Degradation
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The effects of pH, reactant ratio and reaction time on the yields of 5-methylpyrrole-2-carboxaldehyde (6), 6-methyl-3-pyridinol (7), methyl 2-pyrrolyl ketone (8) and 2-methyl-3-pyridinol (9) in the reaction of D-glucose with glycine at 100 deg C in aqueous solution have been studied.THe use of -D-glucose showed that the methyl group in each of 6-9 is derived from C-6 of the glucose.The formation of 6-9 from some potential intermediates in the glucose-glycine reaction has also been investigated.The results support the previously proposed routes to 6 and 7 but disqualify those to 8 and 9.Based on the smooth formation of 8 and 9 from 2-deoxy-D-arabino-hexose (12) and ammonia, a new route to 8 and 9, through an enamine derivated from 12, is proposed.This route involves a modified Strecker degradation, which was supported by the formation of 2,3-dideoxy-D-erythro-hexose from 3-deoxy-D-ribo-hexose and glycine.
- Nyhammar, Tomas,Olsson, Kjell,Pernemalm, Per-Ake
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p. 879 - 890
(2007/10/02)
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- Regioselective Synthesis of Acylpyrroles
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The regioselective synthesis of several pyrrole derivatives is described.AlCl3-catalyzed acylation reactions of 1-(phenylsulfonyl)pyrrole (1) give 3-acyl derivatives, whereas the corresponding BF3*OEt2-catalyzed reactions give 2-acyl derivatives predominantly.Mild alkaline hydrolysis gives the corresponding acyl-1H-pyrroles in excellent yields.AlCl3-catalyzed reactions of 1 with 1,1-dichloromethyl methyl ether and oxalyl chloride give 1-(phenylsulfonyl)-2-formylpyrrole (6) and 1-(phenylsulfonyl)-2-(chlorocarbonyl)pyrrole (7), respectively. 3-Pyrrolylacetic acid (10) was prepared by thallium(III) nitrate promoted rearrangement of 1-(phenylsulfonyl)-3-acetylpyrrole (2a).Trifluoroacetic anhydride catalyzed cyclization of 4-butyric acid (14) gives 1-(phenylsulfonyl)-7-oxo-4,5,6,7-tetrahydroindole (17).Attempts to cyclize 14 at the 4-position have been unsuccessful.
- Kakushima, Masatoshi,Hamel, Pierre,Frenette, Richard,Rokach, Joshua
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p. 3214 - 3219
(2007/10/02)
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- Synthesis and Reactions of N-Protected 2-Lithiated Pyrroles and Indoles. The tert-Butoxycarbonyl Substituent as a Protecting Group
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N-(tert-Butoxycarbonyl)pyrrole and N-(tert-butoxycarbonyl)indole have been prepared and lithiated at the 2-position with lithium 2,2,6,6-tetramethylpiperidide and tert-butyllithium, respectively.These lithium reagents react with a variety of electrophiles to give the 2-substituted N-(tert-butoxycarbonyl)pyrroles and N-(tert-butoxycarbonyl)indoles.The N-(tert-butoxycarbonyl) substituent may be removed rapidly and in high yield from the pyrrole derivatives under basic conditions.For the indole derivatives, the protecting group may be removed with either acidic or basic conditions.
- Hasan, Iltifat,Marinelli, Edmund R.,Lin, Li-Ching Chang,Fowler, Frank W.,Levy, Alan B.
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p. 157 - 164
(2007/10/02)
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- Acid-Mediated Rearrangement of Acylpyrroles
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N-Alkyl-2-acylpyrroles are converted by strong anhydrous acid to 1-alkyl-3-acylpyrroles.An equilibrium mixture of 2- and 3-acylpyrrole is produced by treatment of a 2- or 3-acyl NH pyrrole with acid.Pyrrolecarboxaldehydes similarly afford isomeric mixtures.A cross-ring migration, 7->8, is observed when the adjacent position is blocked.The mechanism of acid-mediated rearrangement of acylpyrroles is discussed.
- Carson, John R.,Davis, Nancy M.
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p. 839 - 843
(2007/10/02)
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- Notes on the Synthesis of meso-Substituted Porphyrins from Pyrryl Carbinols and the Mechanism of the Rothemund Reaction
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Aryl pyrryl carbinols have been found to readily cyclize to meso-substituted tetraarylporphyrins in yields which are consistent with the intermediacy of the pyrryl carbinols in the Rothemund reaction.Acidic solutions of the pyrryl carbinols show absorption bands characteristic of pyrrolylmethenes.It is suggested that pyrrolylmethenes are likely intermediates in the Rothemund reaction.
- Little, Robert G.
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p. 833 - 834
(2007/10/02)
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