- Bioactivity study of thiophene and pyrazole containing heterocycles
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Chalcones 3a-f were prepared by reacting thiophene containing pyrazolyl aldehyde (2) with different 2-hydroxy acetophenones 1a-f. The compounds 3a-f were transformed into different Pyrazolines 4a-f. The formation of chromene derivatives 5a-f occurred from the cyclization of 3a-f, which were then transformed into pyrazole derivatives 6a-f. Newly synthesized compounds have promising antibacterial activity against S. typhii and S. aureus, while weak activity against B. subtilis and E. coli. Compounds 5d and 6d had significant antifungal action towards A. niger, while most of the compounds were moderately active towards T. viride. Some of the synthesized compounds showed promising α-amylase inhibitory activity at 1 mg/mL concentration.
- Athare, Anil E.,Dare, Sushama B.,Kale, Nitin V.,Karale, Bhausaheb K.,Mhaske, Sadhana D.,Salve, Supriya P.,Takate, Sushama J.
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p. 891 - 899
(2021/09/08)
-
- Rhoda-Electrocatalyzed Bimetallic C?H Oxygenation by Weak O-Coordination
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Rhodium-electrocatalyzed arene C?H oxygenation by weakly O-coordinating amides and ketones have been established by bimetallic electrocatalysis. Likewise, diverse dihydrooxazinones were selectively accessed by the judicious choice of current, enabling twofold C?H functionalization. Detailed mechanistic studies by experiment, mass spectroscopy and cyclovoltammetric analysis provided support for an unprecedented electrooxidation-induced C?H activation by a bimetallic rhodium catalysis manifold.
- Tan, Xuefeng,Massignan, Leonardo,Hou, Xiaoyan,Frey, Johanna,Oliveira, Jo?o C. A.,Hussain, Masoom Nasiha,Ackermann, Lutz
-
supporting information
p. 13264 - 13270
(2021/05/06)
-
- Structure-Odor Activity Studies on Derivatives of Aromatic and Oxygenated Monoterpenoids Synthesized by Modifying p-Cymene
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Thymoquinone was recently reported as having a unique pencil-like odor and being the impact compound for the cedar-like and cedar wood-based product smell such as pencils. The compounds thymol and carvacrol are structurally related odorants commonly found in plants and foods such as thyme and oregano, also having a significant contribution to their overall aroma. However, a systematic elucidation of the sensory properties in this class of oxygenated, aromatic monoterpenoids has not been carried out. To close this gap and gain new insights into structure-odor relationships leading to pencil-like and woody odors, 19 structurally related derivatives of p-cymene starting from thymol and carvacrol were synthesized and characterized. The compounds had odor thresholds ranging from 2.0 ng/L air to 388.8 ng/L air, being lowest for thymol and carvacrol and highest for thymohydroquinone. The compounds smelled mostly thyme-like, oregano-like, and pencil-like with phenolic, earthy, and medicinal variations in their odor character, which could be successfully linked to structural motifs.
- Schreiner, Linda,Bauer, Johannes,Ortner, Eva,Buettner, Andrea
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supporting information
p. 834 - 842
(2020/03/30)
-
- Synthesis of natural product inulavosin via Ga(OTf)3-Catalyzed Hetero Diels–Alder Dimerization of salicyl alcohol derivative
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Inulavosin, a natural melanogenesis inhibitor, has been synthesized smoothly from readily available and inexpensive starting materials by using a Ga(OTf)3-catalyzed room temperature hetero Diels–Alder dimerization of salicyl alcohol derivative and a regioselective phenol monobromination as the key steps.
- Gong, Pi-Xian,Li, Hui-Jing,Wang, Meirong,Cheng, Yun-Fei,Wu, Yan-Chao
-
supporting information
p. 2911 - 2916
(2018/10/15)
-
- Enhancing the Acylation Activity of Acetic Acid by Formation of an Intermediate Aromatic Ester
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Acylation is an effective C?C bond-forming reaction to condense acetic acid and lignin-derived aromatic compounds into acetophenones, valuable precursors to fuels and chemicals. However, acetic acid is intrinsically an ineffective acylating agent. Here, we report that its acylation activity can be greatly enhanced by forming intermediate aromatic esters directly derived from acetic acid and phenolic compounds. Additionally, the acylation reaction was studied in the liquid phase over acid zeolites and was found to happen in two steps: 1) formation of an acylium ion and 2) C?C bond formation between the acylium ion and the aromatic substrate. Each of these steps may be rate-limiting, depending on the type of acylating agent and the aromatic substrate. Oxygen-containing substituents, such as ?OH and ?OCH3, can activate aromatic substrates for step 2, with ?OH> ?OCH3, whereas alkyl substituent ?R cannot. At the same time, aromatic esters can rearrange to acetophenones by both an intramolecular pathway and, preferentially, an intermolecular one.
- Duong, Nhung N.,Wang, Bin,Sooknoi, Tawan,Crossley, Steven P.,Resasco, Daniel E.
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p. 2823 - 2832
(2017/07/13)
-
- Synthesis and absolute configuration of natural 8-hydroxyl-9-angeloyloxythymol
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8-Hydroxyl-9-angeloyloxythymol, isolated from Eupatorium fortuneri Turcz, was synthesized for the first time. The synthesis was achieved through a seven-step route, using m-cresol as the starting material and Sharpless asymmetric dihydroxylation to install the quaternary stereogenic center. The enantio-enriched synthetic sample showed spectroscopic data consistent with those of the natural product and thus confirmed the gross structure assigned previously. By comparing the sign for optical rotations of the synthetic and the natural samples, the absolute configuration for the natural product was also assigned. Formula Present.
- Yang, Yong-Qing
-
supporting information
p. 971 - 976
(2016/07/07)
-
- Lithiation of a silyl ether: Formation of an ortho-fries hydroxyketone
-
A hydroxy-directed alkylation of an N,N-diethylarylamide using CIPE-assisted α-silyl carbanions (CIPE=complex-induced proximity effect) has been developed using a simple reagent combination of LDA (lithium diisopropylamide) and chlorosilane. A study of the mechanism, and the application of the procedure to an anionic Snieckus-Fries rearrangement for a highly efficient synthesis of the potent phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, are reported.
- Lo, Hong-Jay,Lin, Chin-Yin,Tseng, Mei-Chun,Chein, Rong-Jie
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supporting information
p. 9026 - 9029
(2014/09/17)
-
- Broadening the catalyst and reaction scope of regio- and chemoselective C-H oxygenation: A convenient and scalable approach to 2-acylphenols by intriguing Rh(ii) and Ru(ii) catalysis
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A unique Rh(ii) and Ru(ii) catalyzed C-H oxygenation of aryl ketones and other arenes has been developed for the facile synthesis of diverse functionalized phenols. The reaction demonstrates excellent reactivity, regio- and chemoselectivity, good functional group compatibility and high yields. The practicality of this method has been proved by gram-scale synthesis of a few different 2-acylphenols. Its utility has been well exemplified in further applications in heterocycle synthesis and direct modifications of drug Fenofibrate.
- Shan, Gang,Han, Xuesong,Lin, Yun,Yu, Shanyou,Rao, Yu
-
supporting information
p. 2318 - 2322
(2013/04/10)
-
- Convergent, fit-for-purpose, kilogram-scale synthesis of a 5-lipoxygenase inhibitor
-
Process research and development of a synthetic route towards a novel 5-lipoxygenase inhibitor is described. The synthetic route provided 1 in 27% yield in nine steps (seven steps in the longest linear sequence) and was performed on kilogram scale. The synthesis began with the preparation of the coumarin core via an efficient von Pechmann condensation. The triazole fragment was obtained via a regioselective copper-catalyzed [3 + 2] cycloaddition between a chiral alkyne and the coumarin azide.
- Ouellet, Stephane G.,Gauvreau, Danny,Cameron, Mark,Dolman, Sarah,Campeau, Louis-Charles,Hughes, Gregory,O'Shea, Paul D.,Davies, Ian W.
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scheme or table
p. 214 - 219
(2012/06/05)
-
- Investigation on the substitution effects of the flavonoids as potent anticancer agents: A structure-activity relationships study
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Three series of flavonoid analogues substituted with different aminomethyl substitutions at C-6, C-7, and C-8 were designed and synthesized for the structure-activity relationship studies as potent anticancer agents. The prepared analogues were evaluated for their in vitro inhibitory activity against the growth of the hepatic cancer cell lines HepG2 and SMMC-7721. Structure-activity relationships indicated that not only the compounds with amino methyl groups were more active than those without the groups in the same series but also the compounds substituted by aminomethyl groups at position C-8 were more active than those at positions C-6 and C-7.
- Wang, Xiao-Bing,Yang, Lei,Kong, Ling-Yi,Liu, Wei,Guo, Qing-Long
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p. 1833 - 1849,17
(2020/07/30)
-
- The phase change storage element and its manufacturing method
-
Disclosed are a phase change RAM device and a method for fabricating a phase change RAM device, which can efficiently lower intensity of current required for changing a phase of a phase change layer. The method includes the steps of providing a semiconductor substrate formed with an insulating interlayer including a tungsten plug, forming a first oxide layer on the semiconductor substrate, forming a pad-type bottom electrode, which makes contact with the tungsten plug, in the first oxide layer, forming a second oxide layer on the first oxide layer including the bottom electrode, and forming a porous polystyrene pattern on the second oxide layer such that a predetermined portion of the second oxide layer corresponding to a center portion of the bottom electrode is covered with the porous polystyrene pattern.
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- Synthesis of ortho-acylphenols through the palladium-catalyzed ketone-directed hydroxylation of arenes
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ortho-Acylphenols are an important structural motif found in a diversity of bioactive molecules ranging from natural products to drugs (Figure 1). Moreover, they also serve as versatile building blocks for the synthesis of various pharmaceuticals, such as warfarin, as well as agrichemicals, flavors, and fragrances. Classic approaches to the synthesis of o-acylphenols generally involve a two-step process: acylation of phenols followed by Fries rearrangement of the resulting phenyl esters (Scheme 1a). On the other hand, direct C-acylation of phenols has also been known under more forcing conditions. Although effective, these approaches are often complicated by the formation of undesired p-substituted products when bulky acyl groups need to be introduced, as well as the limited variety of ketones that can be generated.
- Mo, Fanyang,Trzepkowski, Louis J.,Dong, Guangbin
-
supporting information
p. 13075 - 13079
(2013/02/25)
-
- Pd-catalyzed C-H oxygenation with TFA/TFAA: Expedient access to oxygen-containing heterocycles and late-stage drug modification
-
Functionalized phenols are valuable industrial chemicals related to pharmaceuticals, agrochemicals, and polymers. Therefore, the direct catalytic hydroxylation of arenes to produce phenols has attracted much attention. Although tremendous progress has been made in this field, there are still difficult substrates which remain unmet challenges for direct hydroxylation in terms of regio- and chemoselectivity, as well as the practicality of current methods (Scheme 1). For example, 2-hydroxy aromatic ketones are useful synthetic intermediates for the preparation of various oxygen-containing heterocycles such as benzofuranone, chromanone, benzoxazole, and dibenzooxazepine; they also serve as key building blocks for drugs such as celiprolol, acebutolol, and propafenone. Traditional strategies for accessing 2-hydroxy aromatic ketones have mainly involved the oxidation of benzylic alcohols, the hydrolysis of aromatic halides, Fries rearrangement of esters or the demethylation of methyl phenyl ether. These methods generally suffer from one limitation or another, such as tedious reaction procedures, harsh reaction conditions, low yields, or the formation of side products. Hence, direct transformation of readily available aromatic ketones into valuable 2-hydroxylated products by transition metal-catalyzed C-H functionalization is arguably a highly efficient and atom-economic method to access these compounds. Moreover, developing a more general strategy for the regio- and chemoselective C-H oxygenation of a variety of challenging arenes would be especially desirable for phenol synthesis (Scheme 1).
- Shan, Gang,Yang, Xinglin,Ma, Linlin,Rao, Yu
-
supporting information
p. 13070 - 13074
(2013/02/26)
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- Comparisons of O-acylation and Friedel-Crafts acylation of phenols and acyl chlorides and Fries rearrangement of phenyl esters in trifluoromethanesulfonic acid: Effective synthesis of optically active homotyrosines
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Reactions involving phenol derivatives and acyl chlorides have to be controlled for competitive O-acylations and C-acylations (Friedel-Crafts acylations and Fries rearrangements) in acidic condition. The extent for these reactions in trifluoromethanesulfonic acid (TfOH), which is used as catalyst and solvent, is examined. Although diluted TfOH was needed for effective O-acylation, concentrated TfOH was required for effective C-acylations in mild condition. These results have been applied to the novel synthesis of homotyrosine derivatives. Both Fries rearrangement of N-TFA-Asp(OBn)-OMe and Friedel-Crafts acylation of phenol with N-TFA-Asp(Cl)-OMe in TfOH afforded the homotyrosine skeleton, followed by reduction and deprotection afforded homotyrosines maintaining stereochemistry of Asp as an optically pure form.
- Murashige, Ryo,Hayashi, Yuka,Ohmori, Syo,Torii, Ayuko,Aizu, Yoko,Muto, Yasuyuki,Murai, Yuta,Oda, Yuji,Hashimoto, Makoto
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experimental part
p. 641 - 649
(2011/03/19)
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- A facile demethylation of ortho substituted aryl methyl ethers promoted by AlCl3
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An efficient and practical demethylation of ortho substituted aryl methyl ethers using AlCl3 has been developed. This method gives a high conversion, is simple to operate and is cost-effective. A mechanism involving the complexation of AlCl3 with the OMe and the adjacent electron withdrawing group is proposed. Many functional groups can be tolerated in the demethylation process, and 29 examples gave a demethylated product in a yield of 90-98%.
- Du, Zhen-Ting,Lu, Jing,Yu, Hong-Rui,Xu, Yan,Li, An-Pai
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experimental part
p. 222 - 227
(2010/08/04)
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- Enantioselective synthesis of cyclic sulfamidates via Pd-catalyzed hydrogenation
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Using Pd(CF3;CO2)2/(S,S)-f-binaphane as the catalyst, an efficient enantioselective synthesis of cyclic sulfamidates was developed via asymmetric hydrogenation of the corresponding cyclic imines in 2,2,2-trifluoroethanol at room temperature with high enantioselectivities (up to 99% ee).
- Wang, You-Qing,Yu, Chang-Bin,Wang, Da-Wei,Wang, Xiao-Bing,Zhou, Yong-Gui
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supporting information; experimental part
p. 2071 - 2074
(2009/04/18)
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- Regioselective ortho-acylation of phenol and naphthol derivatives catalyzed by FeCl3 under microwave conditions
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Phenol and naphthol derivatives were subjected to regioselective solvent-free ortho-acylation with organic acids in the presence of FeCl 3 under microwave irradiation. The reactions were complete in a short time, and the products were obtained in high yields.
- Naeimi,Moradi
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body text
p. 1757 - 1759
(2009/09/29)
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- Direct acylation of phenol and naphthol derivatives in a mixture of graphite and methanesulfonic acid
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Graphite in methanesulfonic acid is used to prepare o-hydroxyketones by direct acylation of phenol and naphthol derivatives with carboxylic acids. Georg Thieme Verlag Stuttgart.
- Sharghi, Hashem,Hosseini-Sarvari, Mona,Eskandari, Razieh
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p. 2047 - 2052
(2007/10/03)
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- Phytotoxins from Hofmeisteria schaffneri: Isolation and synthesis of 2′-(2″-hydroxy-4″-methylphenyl)-2′-oxoethyl acetate
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Activity-directed fractionation of a CH2Cl2-MeOH (1:1) extract of Hofmeisteria schaffneri led to the isolation of a new phytotoxin characterized as 2′-(2″-hydroxy-4″-methylphenyl)- 2′-oxoethyl acetate and designated the trivial name of hofmeisterin (1). In addition, the known compounds β-carotene, euparin, and 3′,4′,4a′,9a′-tetrahydro-6,7′- dimethylspiro[benzofuran-3(2H),2′-pyrano[2,3-b]benzofuran]-2, 4a′-diol (2) were obtained. The identification of the isolates was accomplished by spectroscopic methods. The structure of 1 was unequivocally confirmed by synthesis. The methyl derivative 1a was also synthesized following the same strategy. Compounds 1 and 2 inhibited radicle growth of Amaranthus hypochondriacus (IC50 = 3.2 × 10-4 and 1.2 × 10-5 M, respectively) and significantly inhibited activation of the calmodulin (CaM)-dependent enzyme cAMP phosphodiesterase (PDE) with IC 50 values of 4.4 and 4.22 μM, respectively.
- Perez-Vasquez, Araceli,Reyes, Adelfo,Linares, Edelmira,Bye, Robert,Mata, Rachel
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p. 959 - 962
(2008/12/22)
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- QSAR studies of paeonol analogues for inhibition of platelet aggregation
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Various paeonol analogues were synthesized and tested in vitro as inhibitors of platelet aggregation. Structural properties (or descriptors) of paeonol analogues were calculated and the structure-activity relationships were determined. Several multiple linear and nonlinear regression models and back-propagation neural network model were tested and the latter using relative positive charge, hydration energy, and hydrophilic factor as inputs gave the best data fitting with R2 = 0.89 and qpre2=0.66. The correlation coefficient between antiplatelet inhibition activity with an interaction energy between the paeonol compounds with COX-1 enzyme is only 0.39.
- Doble, Mukesh,Karthikeyan,Padmaswar,Akamanchi
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p. 5996 - 6001
(2007/10/03)
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- Microwave assisted direct ortho-acylation of phenol and naphthol derivatives by BF3·(C2H5)2O
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The solventless acylation of phenol and naphthol derivatives with various organic acids and BF3·(C2H5) 2O, under microwave conditions, was studied. High yields of the o-acylated products were achieved in a very short time.
- Naeimi, Hossein,Moradi, Leila
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p. 284 - 287
(2008/02/04)
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- Selective fries rearrangement catalyzed by zinc powder
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Zinc powder in the presence of N,N-dimethylformamide efficiently catalyzes the selective Fries rearrangement of acetylated phenols under microwave heating or with conventional heating using an oil bath. In some cases different products were obtained using microwave heating and conventional heating. Selective migration of the acyl group has been noted with good yields.
- Paul, Satya,Gupta, Monika
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p. 1789 - 1792
(2007/10/03)
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- Titanium(IV) chloride-mediated ortho-acylation of phenols and naphthols
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The use of titanium(IV) chloride as a Lewis acid for direct ortho-acylation of phenols and naphthols proves to be a convenient, more general and direct route to various hydroxyaryl ketones. The route is regioselective, leading to ortho C-acylated products in satisfactory to high yields in most cases.
- Bensari, Ahlem,Zaveri, Nurulain T.
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p. 267 - 271
(2007/10/03)
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- Improvement of Selectivity in the Fries Rearrangement and Direct Acylation Reactions by Means of P2O5/SiO2 Under Microwave Irradiation in Solvent-Free Media
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P2O5/SiO2 was found to be an efficient new reagent for the Fries rearrangement of acyloxy benzene or naphthalene derivatives and the direct acylation reactions of phenol and naphthol derivatives with carboxylic acids. The reactions proceeded smoothly in the solid state and are highly selective methods for the preparation of the ortho isomers of hydroxyaryl ketones. Microwave irradiation improved the conversion yield to 85-100 percent and the high ortho-regioselectivity of these reactions provides an efficient and versatile procedure for obtaining o-hydroxyaryl ketones in 47-98 percent yield.
- Eshghi, Hossein,Rafie, Mohammad,Gordi, Zinat,Bohloli, Moosa
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p. 1258 - 1270
(2007/10/03)
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- Metal triflates-methanesulfonic acid as new catalytic systems: Application to the Fries rearrangement
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A surprising synergistic effect has been discovered between metal triflates (Mg, Ca, Sc, Cu, Zn, Y, Ln, Bi) and methanesulfonic acid, leading to active catalytic systems for the Fries rearrangement. In particular, the systems based on yttrium and copper(II) triflate proved to be very active and much cheaper than scandium triflate. The efficiency of these systems might result from the catalytic Lewis acid activation of Br?nsted acids.
- Mouhtady, Omar,Gaspard-Iloughmane, Hafida,Roques, Nicolas,Le Roux, Christophe
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p. 6379 - 6382
(2007/10/03)
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- The synthesis of a natural product family: From debromoisolaurinterol to the aplysins
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Total syntheses of (±)-aplysin 1, (±)-debromoaplysin 2, (±)-isoaplysin 3, (±)-aplysinol 4, (±)-debromoaplysinol 5, (±)-aplysinal 6, (±)-isolaurinterol 7 and (±)-debromoisolaurinterol 8 are described. Key features are a diastereoselective, sulfur mediated radical cyclisation of diene 12 to give 35; a new radical to polar crossover sequence mediated by Bu3Sn that transforms diene 12 into (±)-debromoisolaurinterol 8; and a series of biomimetic cyclisation and oxidation reactions.
- Harrowven, David C,Lucas, Matthew C,Howes, Peter D
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p. 791 - 804
(2007/10/03)
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- Thymol derivatives having anti-tumor activity, and anti-cancer agent comprising the same
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The present invention relates to a thymol derivative represented by following Chemical Formula 1, pharmaceutically acceptable salts or esters thereof, and anti-cancer agents comprising the same as an active ingredient.
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- A simple and direct method for converting thioamides into thioesters
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Thioamides may be transformed into thioesters through the simple expedient of warming them in an aqueous THF solution containing an alkylating agent. Reactions proceed in high yield and are amenable to multi-gram scale.
- Harrowven, David C.,Lucas, Matthew C.,Howes, Peter D.
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p. 1187 - 1196
(2007/10/03)
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- Total syntheses of aplysin and debromoaplysin using a diastereoselective, sulfur mediated radical cyclisation strategy
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Total syntheses of two marine sesquiterpenes, aplysin 1 and debromoaplysin 2, are described. The key step involves a diastereoselective, sulfur mediated radical cyclisation of diene 5 to 7 which simultaneously creates the sterically demanding aplysin skeleton and establishes the relative configuration of the three contiguous stereogenic centres.
- Harrowven, David C.,Lucas, Matthew C.,Howes, Peter D.
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p. 4443 - 4444
(2007/10/03)
-
- Synthesis and in-vitro evaluation of platelet aggregation inhibitory activity of paeonol and its analogues
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Paeonol (1-(2-hydroxy-4-methoxyphenyl)ethanone) and a series of substituted 1-(2-hydroxyphenyl)ethanone derivatives were synthesized and screened as inhibitors of platelet aggregation. The compounds with the greatest anti-platelet potential among the series tested were 1-(2,5-dihydroxyphenyl)ethanone (65.36% inhibition at 300 μM against 5 μM ADP), paeonol(36.31%), 1-(2-hydroxy-5-methoxyphenyl)ethanone (24.47%), 1-(2-hydroxy-5-nitrophenyl) ethanone (30.40%) and 1-(5-chloro-2-hydroxy-4-methylphenyl)ethanone (24.43%).
- Akamanchi,Padmawar,Thatte,Rege,Dahanukar
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p. 323 - 329
(2007/10/03)
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- Alumina in Methanesulfonic Acid (AMA) as a New Efficient Reagent for Direct Acylation of Phenol Derivatives and Fries Rearrangement. A Convenient Synthesis of o-Hydroxyarylketones
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Alumina in methanesulfonic acid (AMA) is used to prepare o-hydroxyaryl ketones by acylation of phenol and naphthol derivatives with carboxylic acids and the Fries rearrangement of phenolic esters. Mechanistic studies show that the acylation reaction in AMA occurred through an esterification followed by a Fries rearrangement of the phenolic ester by an intermolecular mechanism.
- Sharghi, Hashem,Kaboudin, Babak
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p. 2678 - 2695
(2007/10/03)
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- The Catalytic Fries Rearrangement and o-Acylation Reactions Using Group 3 and 4 Metal Triflates as Catalysts
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Group 3 and 4 metal triflates (Sc(OTf)3, TiCl(OTf)3, Zr(OTf)4, and Hf(OTf)4) were found to be efficient catalysts in the Fries rearrangement of phenyl or 1 -naphthyl acylates. It was also found that the o-acylation (direct acylation) reactions of phenols and 1-naphthols with acid chlorides proceeded smoothly in the presence of the triflates. Both reactions were successfully carried out using small amounts of the triflates (catalytically), and comparison of catalytic activities of these metal triflates in these reactions is discussed.
- Kobayashi, Shue,Moriwaki, Mitsuhiro,Hachiya, Iwao
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p. 267 - 273
(2007/10/03)
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- Hafnium trifluoromethanesulfonate (Hf(OTf)4) as an efficient catalyst in the Fries rearrangement and direct acylation of phenol and naphthol derivatives
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Hafnium trifluoromethanesulfonate (hafnium triflate, Hf(OTf)4) was found to be an efficient catalyst in the Fries rearrangement of acyloxy benzene or naphthalene derivatives. The reactions proceeded smoothly in the presence of 5-20 mol% Hf(OTf)4. Regioselective direct acylation of phenol and naphthol derivatives with acid chlorides was also achieved by using Hf(OTf)4 as a catalyst.
- Kobayashi, Shue,Moriwaki, Mitsuhiro,Hachiya, Iwao
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p. 2053 - 2056
(2007/10/03)
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- Microwave assisted Fries rearrangement on K 10 montmorillonite
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An expeditious solvent free Fries rearrangement is described which occurs under mild conditions on K 10 montmorillonite using microwave radiations.
- Kad,Trehan,Kaur,Nayyar,Arora,Brar
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p. 734 - 736
(2007/10/03)
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- Zirconium tetrachloride as a mediator for ambient temperature ortho-Fries rearrangements
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Zirconium tetrachloride has been found to be an excellent mediator of the Fries reaction. Rearrangements occur at ambient temperature and are highly selective; giving the acetophenone derived from acetyl migration to the sterically least encumbered adjacent carbon.
- Harrowven, David C.,Dainty, Richard F.
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p. 7659 - 7660
(2007/10/03)
-
- Catalytic direct C-acylation of phenol and naphthol derivatives using carboxylic acids as acylating reagents
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Direct regioselective C-acylation of phenol and naphthol derivatives was carried out by using carboxylic acids as acylating reagents. The reactions proceeded smoothly in the presence of a catalytic amount of Hf(OTf)4 to afford the corresponding aromatic ketones in good yields.
- Kobayashi, Shu,Moriwaki, Mitsuhiro,Hachiya, Iwao
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p. 4183 - 4186
(2007/10/03)
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- Bis (biaryl) compounds as inhibitors of leukotriene biosynthesis
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Compounds having the Formula I: STR1 are inhibitors of leukotriene biosynthesis. These compounds are useful as anti-asthmatic, anti-allergic, anti-inflammatory, and cytoprotective agents. They are also useful in treating angina, cerebral spasm, glomerular nephritis, hepatitis, endotoxemia, uveitis, and allograft rejection and in preventing the formation of atherosclerotic plaques.
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- Reactions of endocyclic linearly conjugated dienolates with Michael acceptors leading to bicyclo[2.2.2] octane derivatives. Application to the synthesis of C13 degradation products of carotenoids
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The endocyclic linearly conjugated dienolates from substituted cyclohex-2-enones react with but-3-en-2-one, substituted methyl propenoates, but-3-yn-2-one and methyl propiolate to afford bicyclo[2.2.2]-oct-2-en-1-ols 10a-c, 14a-c and bicyclo[2.2.2]octa-2,5-dien-1-ols 15a,b. The AlCl3-catalysed reaction of 3,5,5-trimethyl-Htrimethylsiloxy)cyclohexa-l)3-diene 3 with (E)-4-acetoxy- and (E)-4-methoxy-but-3-en-2-one provides trans-8-acetoxy-7-acetyl-3,5,5-trimethyl-1-(trimethylsiloxy)bicyclo[2.2.2]oct-2- enes 22, 23 and trans-7-acetyl-8-methoxy-3,5,5-trimethyl-1-(trimethylsiloxy)bicyclo[2.2.2]oct-2- enes 24, 25. Starting from these bicyclo[2.2.2]octenes, the C13 degradation products of carotenoids including 3-oxo-α-ionone 20, blumenol-C 27 and 1,3,7,7-tetramethyl-2-oxabicyclo[4.4.0]decan-9-one 29 have been synthesized.
- Ito, Nobuhiko,Etoh, Takeaki
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p. 2397 - 2405
(2007/10/03)
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- A SYNTHESIS OF 3-HYDROXYMETHYL-6-METHYLBENZOFURAN
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3-Hydroxymethyl-6-methylbenzofuran, a thymol derivative recently isolated from Ageratina glechonophylla, has now been synthesized.
- Gonzalez, Antonio G.,Barrera, Jaime Bermejo,Hernandez, Carlos Yanes
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p. 1311 - 1315
(2007/10/02)
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- QUINOLINYL-BENZOPYRAN DERIVATIVES AS ANTAGONISTS OF LEUKOTRIENE D4
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This invention relates to certain quinolinyl-benzopyran compounds and their use as valuable pharmaceutical agents, particularly as lipoxygenase inhibitors and/or leukotriene antagonists and/or mediator release inhibitors possessing anti-inflammatory and anti-allergic properties.
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- QUINOLINYL-CHROMONE DERIVATIVES AND USE FOR TREATMENT OF HYPERSENSITIVE AILMENTS
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This invention relates to certain quinolinyl-chromone compounds and their use as valuable pharmaceutical agents, particularly as lipoxygenase inhibitors and/or leukotriene antagonists possessing anti-inflammatory and anti-allergic properties.
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- Studies on Aromatic Sesquiterpenes. XI. Synthesis of 7-Isopropyl-3,5-dimethyl-1-naphthol
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Starting from m-cresol, the title new naphthol was synthesized through 4-methyl-3-(2-methoxy-4-methylbenzoyl)pentanoic acid as a key intermediate.
- Tanaka, Juichi,Adachi, Kazuo
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p. 2102 - 2104
(2007/10/02)
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- Modification of Photochemical Reactivity by Cyclodextrin Complexation: Product Selectivity in Photo-Fries Rearrangement
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Cyclodextrin encapsulation, both in the solid state and in aqueous solution brings about a remarkable regulation of the photo-Fries rearrangement of phenyl esters and anilides.In comparison to the non-selective mixture of ortho and para-rearranged isomers along with the deacylated product obtained in organic solvents, the solid β-cyclodextrin complexes of unsubstituted esters and anilides show a remarkable 'ortho-selectivity'.An impressive 'regio-selectivity' among the two ortho-rearranged isomers is observed for meta-substituted esters and anilides upon irradiation as β-cyclodextrin complexes.Specific orientations of the unsubstituted and meta-substituted esters and anilides in the β-cyclodextrin cavity are suggested to be responsible for the observed selectivity.
- Syamala, M. S.,Rao, B. Nageswer,Ramamurthy, V.
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p. 7234 - 7242
(2007/10/02)
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- OXYGENATION OF SUBSTITUTED 2'-HYDROXYACETOPHENONE 4-BROMOPHENYLHYDRAZONES PROMOTED BY COBALT(II) SCHIFF BASE COMPLEX
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Substituted 2'-hydroxyacetophenone 4-bromophenylhydrazones are oxygenated readily in the presence of Co(Salpr) in ethanol to give 2-(4-bromophenylazo)-1,3-benzodioxoles in good yield.The results are rationalized in terms of the decomposition of a peroxy cobalt(III) complex intermediate by a mechanism similar to the Darkin oxidation.
- Nishinaga, Akira,Yamazaki, Shigekazu,Matsuura, Teruo
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p. 5805 - 5808
(2007/10/02)
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- Infrared study of polysubstitution effects in benzophenones and acetophenones: contribution of inter and intracycle interaction mechanisms
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The carbonyl stretching frequencies of substituted 2-Me, 2,6-diMe, 2-MeO benzophenones and 2-Me, 2-MeO acetophenones have been measured in diluted CCl4 solutions.Two interaction mechanisms are observed.In X, Y substituted benzophenones with X on the same cycle as the ortho group and Y on the other cycle, it is shown that for X=Y, the effect of Y is greater than that of X except for very strong electron-releasing substituents.In this last case, the observed enhancement is attributed to the joint effects of intercycle interactions excercised on X and Y and of intracycle interaction on X.These results are corroborated by the study of substituted acetophenones in which only the intracycle mechanism can play a role.
- Goethals, G.,Nadio, L.,Uzan, R.
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p. 199 - 204
(2007/10/02)
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