- A PHOTOCHEMICAL SYNTHESIS OF 4-HYDROXYINDOLE
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1-Alkoxycarbonyl-4-hydroxyindoles were prepared in ca. 25percent yields from 5-(alkoxycarbonylamino)isoquinoline 2-oxides by irradiation in an aprotic solvent, followed by an acid treatment under solvolytic conditions. 1-benzyloxycarbonyl-4-hydroxyindole was then converted to the title compound by catalytic hydrogenation.
- Kaneko, Chikara,Okuda, Wakako,Karasawa, Yoshio,Somei, Masanori
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Read Online
- Synthetic method of 4-hydroxyindole
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The invention belongs to the technical field of organic synthesis, and particularly relates to a synthetic method of 4-hydroxyindole. Aiming at the problems existing in industrial production of 4-hydroxyindole in the prior art, the technical scheme of the invention is as follows: the method comprises the following steps: (1) protecting hydroxyl in a compound 3 by using a protective group to obtaina compound 4; (2) reacting the compound 4 with N, N-dimethylformamide dimethyl acetal to obtain a compound 5; (3) mixing the compound 5 with NH2NH2.H2O and MeOH, and carrying out a reaction to obtaina compound 6; and (4) removing the protective group of the compound 6 to obtain 4-hydroxyindole. According to the method for synthesizing 4-hydroxyindole, the cost of starting materials is low, the reaction conditions in the synthesis process are mild, operation is convenient, aftertreatment is simple, and the yield is high.
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Paragraph 0039; 0077-0083
(2021/03/30)
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- Method for synthesizing 4 -hydroxyindole
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The invention discloses a novel method for synthesizing 4 -hydroxyindole, and belongs to the field of medical intermediate synthesis. With 1, 3 - Cyclohexanedione reacts with 2 - aminoethanol to produce a corresponding enamine compound which is then converted to 4 - hydroxyindole in the presence of a supported or framework-type metal catalyst. The synthesis route is short in step, high-temperature reaction of the pressure vessel is avoided, 4 - hydroxyl indole synthesis efficiency and safety are improved. 2 - Aminoethanol is adopted as the synthetic raw material, the use of higher 2 - chloroacetaldehyde is avoided, the reaction by-product with 1 and 3 - cyclohexanedione is water, and the reaction by-product of the generated enamine under the action of the catalyst is H. 2 , 4 - Hydroxyl indole production cost is reduced.
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Paragraph 0025; 0028-0029; 0030; 0033-0034
(2021/09/01)
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- Synthesis of Substituted Anilines from Cyclohexanones Using Pd/C-Ethylene System and Its Application to Indole Synthesis
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The synthesis of anilines and indoles from cyclohexanones using a Pd/C-ethylene system is reported. A simple combination of NH4OAc and K2CO3 under nonaerobic conditions was found to be the most suitable to perform this reaction. Hydrogen transfer between cyclohexanone and ethylene generates the desired products. The reaction tolerates a variety of substitutions on the starting cyclohexanones.
- Maeda, Katsumi,Matsubara, Ryosuke,Hayashi, Masahiko
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supporting information
p. 1530 - 1534
(2021/03/08)
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- 4-hydroxyindole preparation method suitable for industrial production
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The invention relates to the technical field of organic synthesis, in particular to a preparation method of a medical intermediate 4-hydroxyindole. The method includes: taking 1, 5, 6, 7-tetrahydro-4H-indole-4-one as the raw material, carrying out nucleophilic substitution reaction under the action of alkali to obtain an amino protection product (I), reacting the compound (I) with a halogenation reagent to obtain alpha-halogenated ketone (II), subjecting the compound (II) to elimination reaction under the action of alkali to remove HX so as to obtain a 4-hydroxyindole derivative (III), and finally conducting hydrolysis deprotection on the compound (III) to obtain 4-hydroxyindole (IV). The invention provides a simple industrial production route for 4-hydroxyindole, and the method has the advantages of simple reaction operation, avoidance of high temperature, high pressure and catalytic reaction, and low cost.
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Paragraph 0071; 0072
(2019/11/19)
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- Synthesis and structure eassessment of psammopemmin a
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We have isolated meridianins A, B, C, and E from the Antarctic tunicate Synoicum sp. In the process of verifying the structure of these compounds it was noted that the physical data reported for meridianins bore a striking resemblance to that of psammopemmins. The psammopemmins are alkaloids bearing similar structures to the meridianins, but reported from the Antarctic sponge Psammopemma sp. To verify the structure originally proposed for psammopemmin A, the compound was synthesized. By comparing the 1H and 13C NMR data of reported and synthetic psammopemmin A with that of meridianin A, we infer that the correct structure of psammopemmin A isolated from Psammopemma sp. is actually that of meridianin A.
- Lebar, Matthew D.,Baker, Bill J.
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experimental part
p. 862 - 866
(2011/08/09)
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- Synthesis and adrenolytic activity of 1-(1H-indol-4-yloxy)-3-{[2-(2-methoxyphenoxy)ethyl]amino}propan-2-ol and its enantiomers. Part 1
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The synthesis of (2RS)-1-(1H-indol-4-yloxy)-3-{[2-(2-methoxyphenoxy)ethyl]amino}propan-2-ol ((RS)-9) and its enantiomers has been described and tested for electrocardiographic, antiarrhythmic, hypotensive and spasmolytic activities as well as for α1-, α2- and β1-adrenoceptors' binding affinities. All compounds significantly decrease systolic and diastolic blood pressure, and possess antiarrhythmic activity and affinity to α1-, α2- and β1-adrenoceptors. The results suggest that the antiarrhythmic and hypotensive effects of these compounds are related to their adrenolytic but not spasmolytic properties.
- Groszek, Grazyna,Bednarski, Marek,Dybala, Malgorzata,Filipek, Barbara
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scheme or table
p. 809 - 817
(2009/09/05)
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- Highly chemoselective reduction using a Rh/C-Fe(OAc)2 system: Practical synthesis of functionalized indoles
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Here, we report a highly effective and chemoselective method of preparing substituted indoles from (E)-2-nitropyrrolidinostyrenes via hydrogenation in the presence of a rhodium catalyst doped by additives such as Ni(NO 3)2·6H2O, Fe(OAc)2 or Co(acac)3. These hydrogenation conditions may also be applied to other substrates. Aromatic nitro compounds and olefins can be selectively reduced in the presence of aromatic benzyl ethers, aromatic halides and aromatic aldehydes.
- Akao, Atsushi,Sato, Kimihiko,Nonoyama, Nobuaki,Mase, Toshiaki,Yasuda, Nobuyoshi
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p. 969 - 972
(2007/10/03)
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- PROCESS FOR PRODUCING INDOLOPYRROLOCARBAZOLE DERIVATIVE
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The present invention provides a process for industrially advantageously producing a compound represented by the formula (I): or a pharmaceutically acceptable salt thereof, which is useful as an anticancer agent, and also provides a catalyst used for hydrogenation reaction in the process.
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Page/Page column 38
(2010/02/11)
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- Process for the preparation of indole compounds
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The present invention relates to a novel process for the preparation of a monohydroxyindole or dihydroxyindole compound by a single step of placing in contact, in a solvent medium, at least one hydrolase with at least one indole compound bearing one or two radicals connected by an ester function to the benzene ring.
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- Palladium-Catalyzed Synthesis of Indoles by Reductive N-Heteroannulation of 2-Nitrostyrenes
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A palladium-phosphine catalyzed reductive N-heteroannulation of 2-nitrostyrenes, in the presence of carbon monoxide, producing indoles has been developed. Indoles were obtained, in moderate to excellent yield, from substituted 2-nitrostyrenes having either electron-withdrawing (NO2 and CO2-Me) or electron-donating (Br, OH, Me, OMe, and OTf) substituents on the aromatic ring. Best results were obtained using palladium diacetate (6 mol percent) together with triphenylphosphine (24 mol percent) as the catalytic system, under 4 atm of carbon monoxide in acetonitrile at 70 °C. Other palladium(II) and palladium(0) complexes also catalyze the reaction.
- So?derberg, Bjo?rn C.,Shriver, James A.
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p. 5838 - 5845
(2007/10/03)
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- Product based on inorganic or organic lamellar particles, containing a melanotic pigment, process for preparing it and its use in cosmetics
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The invention relates to a product in powder form consisting of organic or inorganic particles having a lamellar structure, having a size of less than 50 microns and containing at least one synthetic melanotic pigment formed in situ by oxidation of an indole compound, and to its use for the protection of the human epidermis, in make-up products and for dyeing hair.
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- Process for dyeing keratinous fibres based on monohydroxyindole and 5,6-disubstituted hydroxyindole and composition employed
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The invention relates to a process for dyeing keratinous fibres, comprising the application on these fibres, in a first stage, of a composition (A) containing, in a medium suitable for dyeing: (i) at least one monohydroxyindole corresponding to the formula (I): STR1 in which: R1 denotes hydrogen or alkyl; and R2 and R3 denote hydrogen, NH2, OH, COOH, CH2 COOH, CONH2, alkyl optionally substituted with OH or NH2, alkoxy, CONHR4, CON(R5)(R6) or CO2 R4, in which R4, R5 and R6 denote alkyl; halogen, and (ii) at least one 5,6-disubstituted hydroxyindole of formula (II): STR2 in which: R6 denotes hydrogen or acetyl; R4 denotes hydrogen, methyl, carboxy or ethoxycarbonyl; and R5 denotes hydrogen or methyl, with the proviso that, when R6 denotes acetyl, R4 and R5 represent a hydrogen atom; and its salts; in a second stage, a rinsing of the treated fibres is performed; and in a third stage, a composition (B) containing periodic acid or one of its salts in an aqueous medium is applied.
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- Process for dyeing keratin fibres with a monohydroxyindole associated with an iodide and hydrogen peroxide
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Process for dyeing keratin fibres consisting in applying on these fibres a composition (A) containing at least one indole colorant of formula: STR1 where R1 =H or C1 -C4 alkyl; R2 and R3, which may be identical or different, denote H, C1 -C4 alkyl, carboxyl or alkoxycarbonyl; or a salt or a precursor of a compound (I), associated, either with iodide ions, or with H2 O2 ; application of composition (A) being preceded or followed by the application of a compound (B) which contains, either H2 O2 at a pH of 2 to 12 when (A) contains iodide ions, or iodide ions at a pH of 2 to 11 when (A) contains H2 O2. This process allows particularly powerful and resistant dyes to be made.
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- Process for dyeing keratinous fibres with a hydroxyindole in combination with a quinone derivative; and novel 1,4-benzoquinones
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Process for dyeing keratinous fibres, comprising the step of applying to these fibres at least one composition A containing, in a medium appropriate for dyeing, at least one mono- or di-hydroxyindole the application of the composition A being preceded or followed by the application of a composition B containing, in a medium appropriate for dyeing, at least one quinone derivative chosen from ortho- or para-benzoquinones, monoimines or diimines of ortho- or para-benzoquinones, 1,2- or 1,4-naphthoquinones, sulphonimides of ortho- or para-benzoquinones, α, ω-alkylene-bis-1,4-benzoquinones, or 1,2- or 1,4-naphthoquinone-monoimines or -diimines; the mono- or di-hydroxyindoles and the quinone derivatives being chosen such that the oxidation-reduction potential difference ΔE between the oxidation-reduction potential Ei of the mono- or di-hydroxyindoles, determined at pH 7 in a phosphate medium on a vitreous carbon electrode by voltametry, and the oxidation-reduction potential Eq of the quinone derivative determined at pH 7 in a phosphate medium by polarography on a mercury electrode and relative to a saturated calomel electrode is such that
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- Chemo-enzymatic synthesis and characterization of L-tryptophans selectively 13C-enriched or hydroxylated in the six-membered ring using transformed Escherichia coli cells
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L-(3a-13C)- and L-(6-13C)tryptophan have been synthesized from simple labelled compounds via a single reaction scheme based on the conversion of 1,3-cyclohexanedione into indole.The labelled indoles have been converted in one step into the corresponding L-tryptophans using transformed Escherichia coli cells with large amounts of the enzyme, tryptophan synthease.The same reaction scheme has been used for the synthesis of 4- and 7-indolol.These hydroxyindoles together with 5-indolol have been converted into 4-, 7- and 5-hydroxy-L-tryptophan, respectively, using theEscherichia coli cells.The latter compound is the immediate precursor of the neurotransmitter, serotonin.It appears that 7-indolol is the only indole derivative which is converted faster than unsubstituted indole by the enzyme, tryptophan synthease.With the preparation of L-(3a-13C)- and L-(6-13C)tryptophan, we have completed the series of indoles and L-tryptophans with a stable isotope (13C, 15N or 2H) in the aromatic ring.In this paper, we also discuss the NMR parameters of these mono-isotopically labelled systems.
- Berg, E. M. M. van den,Jansen, F. J. H. M.,Goede, A. T. J. W. de,Baldew, A. U.,Lugtenburg, J.
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p. 287 - 297
(2007/10/02)
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- Process for the preparation of indole derivatives
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The present invention provides a process for the preparation of 4-hydroxyindole derivatives of the general formula: STR1 in which R1 is a hydrogen atom or an alkyl radical containing up to 6 carbon atoms and R2 is a hydrogen atom or an alkyl radical containing up to 6 carbon atoms, wherein a compound of the general formula: STR2 in which R2 has the same meaning as above, is reacted with a compound of the general formula: in which R1 has the same meaning as above and R3 is a reactive residue, to give a 2-(2-imino-6-oxocyclohexylidene)-propionic acid derivative of the general formula: STR3 in which R1, R2 and R3 have the same meanings as above, which is then cyclized in known manner to give a compound of the general formula: STR4 in which R1 and R2 have the same meaning as above, which is subsequently dehydrated. The present invention also provides new 4-hydroxyindoles of general formula (I'), as well as new 4-Oxo-4,5,6,7-tetrahydroindoles of general formula (IV).
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- Reactions of Organic Anions, 147.- Simple and General Synthesis of Hydroxy- and Methoxyindoles via Vicarious Nucleophilic Substitution of Hydrogen
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A simple synthesis of 4-, 5-, 6-, and 7-hydroxy- and -methoxyindoles via cyanoalkylation of O-protected nitrophenols by vicarious nucleophilic substitution of hydrogen, followed by catalytic hydrogenation of the (2-nitroaryl)acetonitriles obtained is described.
- Makosza, Mieczyslaw,Danikiewicz, Witold,Wojciechowski, Krzysztof
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p. 203 - 208
(2007/10/02)
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- Palladium-Catalyzed Coupling of 2-Bromoanilines with Vinylstannanes. A Regiocontrolled Synthesis of Substituted Indoles
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The palladium-catalyzed cross-coupling reaction of aryl halides and triflates with vinylstannane reagents has been used to produce a variety of substituted indoles.The mild reaction conditions and selectivity inherent in the coupling reaction have been utilized to produce regiochemically pure 4-, 5-, and 6-substituted indoles.
- Krolski, Michael E.,Renaldo, Alfred F.,Rudisill, Duane E.,Stille, J. K.
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p. 1170 - 1176
(2007/10/02)
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- HYDROXYLATION OF INDOLINES AND INDOLES BY HYDROGEN PEROXIDE IN SUPERACIDS
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In SbF5-HF, indolines and indoles are hydroxylated on the aromatic ring, protonated hydrogen peroxide H3O2+ reacting on the protonated substrates.
- Berrier, Christian,Jacquesy, Jean-Claude,Jouannetaud, Marie-Paule,Renoux, Alain
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p. 4565 - 4568
(2007/10/02)
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- Processes for preparing 4-substituted indoles
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A new chemical sequence for preparing indoles is disclosed whose key reactions are reaction of a o-nitrotoluene with tris(dimethylamino)methane to give a β-dimethylamino-o-nitrostyrene which is converted into a semicarbazone and cyclized.
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- SYNTHESIS OF 4-SUBSTITUTED INDOLES FROM o-NITROTOLUENES
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A facile two- or three-step transformation of o-nitrotoluenes into 4-substituted indoles is described.Treatment of o-nitrotoluenes 1 with DMF acetal, or sometimes more advantageously with tris(N,N-dimethylamino)methane, affords β-(N,N-dimethylamino)styrenes 2 which are readily converted too-nitrophenylacetaldehyde semicarbazones 3 without isolation.Reduction of either 2 or 3 affords 4-substituted indoles 4.Use of the very insoluble semicarbazones results in vastly superior yields of 4 by minimizing completing bimolecular condensation reactions during reduction.This new procedure has been applied to efficiently and conveniently prepare a series of 4-substituted indoles 4.
- Kruse, Lawrence I.
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p. 1119 - 1124
(2007/10/02)
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- A FACILE SYNTHESIS OF 4-HYDROXYINDOLE VIA ELECTROCHEMICAL OXIDATIVE C-C COUPLING
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4-hydroxyindole (1a), a useful intermediate for Pindolol (1b), has been prepared via electrooxidative coupling of 1,3-cyclohexadione with ethyl vinyl ether followed by ammonolysis and dehydrogenation.
- Torii, Sigeru,Uneyama, Kenji,Onishi, Takashi,Fujita, Yoshiji,Ishiguro, Michihiro,Nishida, Takashi
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p. 1603 - 1604
(2007/10/02)
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