- Benzyne-Mediated Nonconcerted Pathway toward Synthesis of Sterically Crowded [5]- and [7]Oxahelicenoids, Stereochemical and Theoretical Studies, and Optical Resolution of Helicenoids
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Synthesis of [5]- and [7]oxahelicenoids via Diels-Alder reaction of sterically crowded bichromenes with benzyne is presented. Studies carried out on Diels-Alder addition product establish the unusual preference for a stepwise mechanism over the concerted reaction pathway. This high yielding general synthetic protocol affords unexpected anti cycloadducts [5]- and [7]oxahelicenoids, as confirmed by crystallographic analysis. To rationalize these intriguing antiaddition products, the reaction mechanism was elucidated by means of DFT analysis. Additionally, hydroxy-functionalized [7]oxahelicenoid has been resolved in its optically pure forms.
- Gawade, Prashant M.,Khose, Vaibhav N.,Badani, Purav M.,Hasan, Mohammed,Kaabel, Sandra,Mobin, Shaikh M.,Borovkov, Victor,Karnik, Anil V.
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- Design, synthesis and preliminary bioactivity evaluation of bitopic benzopyranomorpholine analogues as selective dopamine D3 receptor ligands as anti-drug addiction therapeutic agents
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Three series of bitopic benzopyranomorpholine analogues were designed, synthesized, and evaluated as a novel class of selective ligands for the dopamine D3 receptor. Binding affinities of target compounds were determined using the method of radioligand binding assay. Most compounds demonstrated considerable binding affinities and selectivity for D3 receptor. Besides, the compounds were screened for their ability to alleviate withdrawal symptoms of opioid addiction in animal behavioral models. The results showed that compound 20h displayed nanomolar affinity for the D3R, and exhibited anti-drug addiction efficacy in the animal model of of naloxone-induced withdrawal symptoms in morphine-dependent mice.
- Cai, Jin,Chen, Xixi,Huang, Mingqi,Ji, Min,Wang, Yuhong
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- Acid activated montmorillonite K-10 mediated intramolecular acylation: Simple and convenient synthesis of 4-chromanones
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3-Aryloxyproionic acids undergo intramolecular cyclization in the presence of AA.Mont.K-10 in toluene under reflux for 30–45 min in good to excellent yields. Phenyl ring bearing various substituents at the ortho, meta, para positions undergo this cyclization reaction. This method involves simple work up and amenable for large scale preparations. The heterogeneous acid treated catalyst can be regenerated and used for up to three cycles with minimum loss of activity.
- Begum, Ayisha F.,Balasubramanian, Kalpattu K.,Shanmugasundaram, Bhagavathy
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- Benzyne-Mediated Nonconcerted Pathway toward Synthesis of Sterically Crowded [5]- And [7]Oxahelicenoids, Stereochemical and Theoretical Studies, and Optical Resolution of Helicenoids
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Synthesis of [5]- and [7]oxahelicenoids via Diels-Alder reaction of sterically crowded bichromenes with benzyne is presented. Studies carried out on Diels-Alder addition product establish the unusual preference for a stepwise mechanism over the concerted reaction pathway. This high yielding general synthetic protocol affords unexpected anti cycloadducts [5]- and [7]oxahelicenoids, as confirmed by crystallographic analysis. To rationalize these intriguing antiaddition products, the reaction mechanism was elucidated by means of DFT analysis. Additionally, hydroxy-functionalized [7]oxahelicenoid has been resolved in its optically pure forms.
- Badani, Purav M.,Borovkov, Victor,Gawade, Prashant M.,Hasan, Mohammed,Kaabel, Sandra,Karnik, Anil V.,Khose, Vaibhav N.,Mobin, Shaikh M.
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p. 860 - 868
(2021/08/24)
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- Synthesis of Flavanones via Palladium(II)-Catalyzed One-Pot β-Arylation of Chromanones with Arylboronic Acids
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A total of 47 flavanones were expediently synthesized via one-pot β-arylation of chromanones, a class of simple ketones possessing chemically unactivated β sites, with arylboronic acids via tandem palladium(II) catalysis. This reaction provides a novel route to various flavanones, including natural products such as naringenin trimethyl ether, in yields up to 92percent.
- Cho, Yang Yil,Jang, Hyu Jeong,Kim, Dong Hwan,Kim, Nam Yong,Kim, Nam-Jung,Kim, Young Min,Lee, Soo Jin,Lee, Yong Sup,Park, Boyoung Y.,Son, Seung Hwan,Yoo, Hyung-Seok
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supporting information
p. 10012 - 10023
(2019/08/30)
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- A new method for the synthesis of six bromine four hydrogen colors chromone (by machine translation)
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The invention discloses a method for synthesizing six bromine four hydrogen colors recombination, is in the reaction solvent, to phenol and acrylonitrile reaction raw material, under the action of the organic drugs, six bromine four hydrogen colors recombination reaction. The invention mild reaction conditions, cheap raw material, the value of the product is very high. This invention synthetic six bromine four hydrogen colors recombination has very high medicinal value, conducive to diabetes, obesity, disorders of the nervous system in the fields of research and development of new drugs, has extensive use and application market. (by machine translation)
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Paragraph 0013; 0026
(2017/07/13)
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- Synthesis, characterization, and antimicrobial activity of novel substituted 2H-chromenyl acrylates
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The present study deals with conventional Witting olefination of 2H-chromene-3-carbaldehydes with stabilized ylide in the presence of dichloromethane to afford (2E)-ethyl-3-(4-chloro-2H-chromen-3-yl) acrylate derivatives. All the products were found to have E-geometry at C=C bond. The synthesized compounds were characterized by spectral data such as IR, 1H NMR and MS. Compounds were screened for antimicrobial activity against strains of gram positive, gram negative bacterial and fungal strains. All compounds showed good antibacterial and antifungal activity.
- Subhashini,Ravi,Cherupally,China Raju,Reddy,Bee
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p. 2900 - 2905
(2017/03/22)
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- Efficient and rapid synthesis of phenolic analogs of 4-phenylbutanoic acid using microwave-assisted Michael addition as a key reaction
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ABSTRACT: The addition of phenols to acrylonitrile in the presence of aqueous benzyltrimethylammonium hydroxide or tetramethylammonium hydroxide under microwave irradiation yielded the corresponding Michael adducts. The obtained adducts were easily transformed to phenolic analogs of 4-phenylbutanoic acids via the hydrolysis of nitrile groups.
- Iida, Hirokazu,Akatsu, Yusuke,Mizukami, Kazushi,Natori, Sho,Matsukawa, Minako,Takahashi, Kie
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supporting information
p. 581 - 585
(2016/07/06)
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- Catalytic Olefin hydroalkoxylation by nano particles of pollucite
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The catalytic hydroalkoxylation of α,β-unsaturated esters, nitriles, and ethers with aliphatic and aromatic alcohols over pollucite using thermal and microwave-assisted methods was investigated. To study the effect of the alcohol structures on the mechanism of the hydroalkoxylation reaction, different alcohols, such as methanol to butanol, cyclohexanol, phenol, and 2-ethylhexanol were used. The activities of pollucite, in contrast to other basic solids, were scarcely affected by the presence of air and moisture. The correlation between alcohol acidity and reaction activity is discussed. The prepared pollucite was characterized by X-ray diffraction, volumetric nitrogen adsorption surface area analysis, and CO2 temperature-programmed desorption. Scanning electron microscopy analysis revealed that the size of the modified nano catalyst particles was under 40nm.
- Zamanian, Sara,Kharat, Ali Nemati
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p. 981 - 986
(2015/06/25)
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- Cyanoethylation of alcohols and amines by cesium-modified zeolite y
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Zeolite Y modified by cesium and magnesium ions was prepared by ion-exchange and impregnation methods, and its activity in the cyanoethylation of aliphatic and aromatic alcohols and amines was investigated. During the preparation of some samples, the transformation of zeolite Y into a pollucite-type phase occurred. This phase exhibited good activity in the cyanoethylation of aliphatic alcohols. The prepared solids modified by the impregnation method were more active than the ion-exchanged solids. The activities of the catalysts, in contrast to other basic solids, were scarcely affected by the presence of air or moisture. A correlation between catalyst basicity and catalytic activity is discussed. The catalysts were characterized by X-ray diffraction, volumetric nitrogen adsorption surface area measurement, and CO2 temperature-programmed desorption. Scanning electron microscopy revealed that the particles of the modified nanocatalysts were 40 nm. The reaction of acrylonitrile with linear alcohols in the presence of the catalysts was accelerated by microwave irradiation.
- Zamanian, Sara,Kharat, Ali Nemati
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p. 264 - 269
(2014/03/21)
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- An efficient synthesis of 4-chromanones
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A two step efficient and practical synthesis of a variety of 4-chromanones is described. Phenols undergo a Michael addition to acrylonitriles in the presence of catalytic amounts of potassium carbonate and tert-butanol to generate the corresponding 3-aryloxypropanenitriles in 50-93% yields. Treatment of the resulting aryloxypropionitriles with 1.5 equiv of TfOH and 5 equiv of TFA, followed by an aqueous work up afforded 4-chromanones in moderate to excellent yields.
- Zhong, Yong-Li,Boruta, David T.,Gauthier Jr., Donald R.,Askin, David
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supporting information; experimental part
p. 4824 - 4826
(2011/10/04)
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- Solid sodium stannate as a high-efficiency superbase catalyst for anti-Markovnikov hydroamination and hydroalkoxylation of electron-deficient olefins under mild conditions
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A solid superbase with H- above 26.5 has been obtained through thermal treatment of sodium stannate hydrate. It was found to be an efficient catalyst for anti-Markovnikov hydroamination and hydroalkoxylation of electron-deficient olefins under mild conditions.
- Zhang, Shuguo,Wei, Yudan,Yin, Shuangfeng,Au, Chak-Tong
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p. 712 - 716
(2013/01/09)
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- Design and synthesis of highly potent and selective human peroxisome proliferator-activated receptor α agonists
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A combination of benzoxazole, phenoxyalkyl side chain, and phenoxybutyric acids was identified as a highly potent and selective human peroxisome proliferator-activated receptor α (PPARα) agonist. The synthesis, structure-activity relationship (SAR) studies, and in vivo activities of the representative compounds are described.
- Yamazaki, Yukiyoshi,Abe, Kazutoyo,Toma, Tsutomu,Nishikawa, Masahiro,Ozawa, Hidefumi,Okuda, Ayumu,Araki, Takaaki,Oda, Soichi,Inoue, Keisuke,Shibuya, Kimiyuki,Staels, Bart,Fruchart, Jean-Charles
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p. 4689 - 4693
(2008/02/11)
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- Anti-Markovnikov N-H and O-H additions to electron-deficient olefins catalyzed by well-defined Cu(I) anilido, ethoxide, and phenoxide systems
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The monomeric Cu(I) complexes (IPr)Cu(Z) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, Z = NHPh, OEt, or OPh) react with YH (Y = PhNH, PhCH2NH, EtO, or PhO) to catalytically add Y-H bonds across the C=C bond of electron-deficient olefins to yield anti-Markovnikov organic products. Catalytic activity has been observed for olefins CH2C(H)(X) with X = CN, C(O)Me, or CO2Me as well as crotononitrile. Preliminary studies implicate an intermediate in which the C-Y bond forms through a nucleophilic addition pathway. Copyright
- Munro-Leighton, Colleen,Blue, Elizabeth D.,Gunnoe, T. Brent
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p. 1446 - 1447
(2007/10/03)
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- Kinetics and mechanism of thermal gas-phase elimination of β-substituted carboxylic acids
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3-Phenoxypropanoic acid (1), 3-(phenylthio)propanoic acid (2), and 4-phenylbutanoic acid (3) were pyrolysed between 520 and 682 K. Analysis of the pyrolysates showed the elimination products to be acrylic acid and the corresponding arene. Pyrolysis of ethyl 3-phenoxypropanoate (4) and its methyl analogue (5), ethyl 3-(phenylthio)propanoate (6) and its methyl counterpart (7), and 3-phenoxypropane nitrile (8) were also investigated between 617 and 737 K. The thermal gas-phase elimination kinetics and product analysis are compatible with a thermal retro-Michael reaction pathway involving a four-membered cyclic transition state.
- Al-Awadi,Abdallah,Dib,Ibrahim,Al-Awadi,El-Dusouqui
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p. 5769 - 5777
(2007/10/03)
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- Keratinocyte growth inhibitors and hydroxamic acid derivatives
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This invention relates to a keratinocyte-proliferation inhibitor comprising as active ingredient a compound having an activity of inhibiting the solubilization of heparin-binding EGF-like growth factor bound to cell membranes and a compound of the formula (I); or pharmaceutically acceptable salt thereof, wherein R1, R2, R3 are hydrogen atom or alkyl and X is substituted benzene or the like.
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- Hofmann rearrangement of primary, substituted acetamides to nitriles with a hypochlorite liquid triphasic system
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A hypochlorite liquid triphasic system prepared from aqueous sodium hypochlorite, sodium bromide, and tetrabutylammonium hydrogen sulfate was found to be effective in converting primary, substituted acetamides to nitriles with loss of one carbon via the Hofmann rearrangement in yields of 48-68%.
- Correia
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p. 1127 - 1128
(2007/10/02)
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- Syntheses, Reactions, and Molecular Structures of trans-Hydrido(phenylamido)bis(triethylphosphine)platinum(II) and trans-Hydridophenoxobis(triethylphosphine)platinum(II)
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The reaction between trans-PtH(NO3)(PEt3)2 and NaNHPh in C6H6 yields the novel hydridoamido complex trans-PtH(NHPh)(PEt3)2 (I).This compound is stable in solution; however, crystals of I decompose within hours at room temperature.At -100 deg C a crystal of I belongs to the monoclinic space group P21/n with a = 11.445(2) Angstroem, b = 13.010(2) Angstroem, c = 14.888(2) Angstroem, β = 104.63(1) deg, V = 2144.9(6) Angstroem3, and Z = 4.Complex I adopts a trans structure, with Pt-N = 2.125(5) Angstroem, indicative of a single bond weakened by the trans-hydride ligand.The Pt-N-Ph angle of 125.5(4) deg and the observation of the H on N in a position expected for trigonal-planar coordination suggest sp2 hybridization about nitrogen.SCF-DV-Xα calculations of the model complex PtH(NH2)(PH3)2 confirm the expected repulsive nature of the interaction between the nitrogen lone-pair orbital and filled d? orbitals on the metal.This interaction is minimized when the nitrogen lone pair lies in the coordination plane of Pt.The reaction between trans-PtH(NO3)(PEt3)2 and excess NaOPh produces trans-PtH(OPh)(PEt3)2 (II).Crystals of II belong to the triclinic space group PI, and at -50 deg C a = 9.477(3) Angstroem, b = 10.617(3) Angstroem, c = 11.641(3) Angstroem, α = 101.61(2), β = 98.28(2) deg, γ = 104.13(2), V = 1089.5(5) Angstroem3, and Z = 2.This complex is isostructural to I with Pt-O = 2.098(9) Angstroem and Pt-O-Ph = 123.6(7) deg.Complex I undergoes rapid insertion of electrophilic substrates such as CO2.COS, and PhNCO into the Pt-NHPh bond in preference to the metal hydride bond.These reactions in C6H6 solvent do not appear to involve free NHPh(1-) as evidenced by the reaction between PtH((15)NHPh)(PEt3)2, which exclusively yields PtH(PEt3)2 as the initial product.Crossover between PtH(NHPh)(PEt3)2 and PtD((15)NHPh)(PEt3)2 to form PtH((15)NHPh)(PEt3)2 and PtD(NHPh)(PEt3)2 occurs slowly (t1/2 ca. 48 h) at room temperature.Electrophiles such aas CH3I and H2O directly attack bound aniline in PtD(NHPh)(PEt3)2 to produce trans-PtDI(PEt3)2 and trans-PtD(OH)(PEt3)2, along with NH(CH3)Ph and NH2Ph, respectively.The electrophilic olefin acrylonitrile inserts into the Pt-N bond to form trans-PtH(PEt3)2 (III).Crystals of III belong to the monoclinic space group P21/c and at 22 deg C a = 14.260(6) Angstroem, b = 14.021(6) Angstroem, c = 13.240(6) Angstroem, β = 107.96(3) deg, V = 2519(3) Angstroem3, and Z = 4.The structure shows a 3-anilinopropionitrile ligand trans to hydride ?-bound to platinum (Pt-C = 2.198(13) Angstroem) by the 2-carbon atom.Complex III undergoes C-H reductive elimination on heating to 70 deg C to produce 3-anilinopropionitrile.Methyl acrylate appears to undergo a similar insertion reaction; however, the organic product is unstable toward elimination in the presence of "Pt(PEt3)2"...
- Cowan, Robert L.,Trogler, William C.
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p. 4750 - 4761
(2007/10/02)
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- A NEW SYNTHETIC APPROACH TO THE ROTENOID RING SYSTEM
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The (+)-cis-chromanochromanones (2) and (3), respresenting the basic ring system of the natural insecticide rotenone, have been synthesised by a general procedure; the key step is 4-aroylation of the 4-(phenyl-sulphonyl)chromans (7; Z=SO2Ph).
- Lai, Steven M. F.,Orchison, Jack J. A.,Whiting, Donald A.
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p. 5895 - 5906
(2007/10/02)
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- NOUVEAUX DERIVES DE LA BENZOPYRANNONE-4, A ACTIVITES ANALGESIQUE, ANTI-INFLAMMATOIRE ET ANTIAGREGANTE PLAQUETTAIRE
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A series of 35 new derivatives of 3-benzylidene benzopyran-4-one carboxylic acid was synthesized; their antiinflammatory and analgesic activities were investigated and compared with those of acetylsalicylic acid, phenylbutazone, ketoprofene and glafenine.Among these compounds, four were found to be more potent than the references compounds in tests of antiinflammatory and analgesic activity.Seven compounds were tested on rat blood platelet aggregation induced by ADP.From these tests, HD-039, HD-041, HD-044 and HD-049 appear to be promising antiinflammatory, analgesic and anticlotting agents, although this original series shows little structural analogy with classical non-steroidal antiinflammatory agents.
- Darmanaden, R.,Dhanutirto, H.,Castel, J.,Loubatiere, J.,Flandre, O.
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p. 876 - 887
(2007/10/02)
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- Pseudo One-Step Cleavage of C-C Bonds in the Decomposition of Ionized Carboxyclic Acids. Radical Like Reactions in Mass Spectrometry
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Metastable molecular ions of hexanoic acid (1) decompose unimolecularly to C2H5. and protonated methacrylic acid (5-H+)(92percent rel. abund.).Investigation of the mechanism reveals that 1) the branched cation radical 11 must be regarded as the essential intermediate in the course of the rearrangement/dissociation reaction and 2) the process commences with intramolecular hydrogen transfer from either C-3 or C-5 to the ionized carbonyl oxygen ("hidden" hydrogen migration).Hydrogen transfer from C-4, which would correspond to the well-known McLafferty rearrangement, is of no importance in the C2H5.-elimination from 1.The same conclusion applies for various alternative mechanisms, as for example a SRi type reaction, 1 -> 2-H+.The gas phase chemistry of the cation radical of 1, and in particular the hydrogen exchange processes between the methylene groups C-2/C-3 and C-5/C-6, is in surprisingly close correspondence to the chemistry of free alkyl radicals. - The syntheses of various 13C and 2H-labelled model compounds are described.
- Weiske, Thomas,Schwarz, Helmut
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p. 323 - 347
(2007/10/02)
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- Studies in Antifertility Agents: Part XXIX - synthesis of 4--3-benzylchromans
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7-H/Methoxy-4-chromanones (1, 2), obtained by PPA cyclization of the respective β-aryloxypropionic acids, on treatment with araldehydes (3, 4) give the corresponding 3-arylidene-4-chromanones (5, 6).Catalytic hydrogenation of 5 and 6 over Pd-C (10percent) with one mole of hydrogen affords 3-benzyl-4-chromanones (7, 8), while hydrogenation of 6 yields 3-benzyl-7-methoxychroman (9).NaBH4 reduction of 7 and 8 gives the corresponding 4-chromanols (10, 11) as a mixture of 3,4-cis- and -trans-isomers, which are arylated as such with PhOH-AlCl3 to give 4-(p-hydroxyphenyl)chromans(12, 13) as the main products.Treatment of 12 and 13 with Ac2O-pyridine and with p-NO2C6H4COCl-pyridine yields the corresponding p-acetoxy (14, 15) and p-nitrobenzoyloxy (16, 17) derivatives.Alkylation of 12 and 13 with N-(β-chloroethyl)pyrrolidine hydrochloride furnishes the title compounds, 4--3-(p-chloro/H)benzyl-7-H/methoxy-chromans (18, 19).None of these compounds prevents pregnancy at 5 mg/kg dose in rats.
- Sangwan, Naresh K.,Rastogi, Shri Nivas
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p. 500 - 503
(2007/10/02)
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