- 8-Br-quinoline derivatives as sensitizers combining two-photon induced fluorescence and singlet oxygen generation
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The present study describes the synthesis of a series of original 8-Br-quinoline derivatives with an arylethynyl moiety at the C6 position, based on Friedl?nder and Sonogashira coupling key reactions. Investigation of their photophysical and two-photon absorption (2PA) properties reveals that these structures can lead to 2PA chromophores combining fluorescence and singlet oxygen generation properties. As a result, chromophores, which combine significant 2PA responses in the NIR region, good photosensitization ability (ΦΔ=0.4-0.6) and fluorescence properties (Φf=0.2-0.6) have been identified. These multifunctional derivatives hold promise as original dyes for combined two-photon imaging and photodynamic therapy.
- Picard, Sébastien,Clermont, Guillaume,Genin, Emilie,Blanchard-Desce, Mireille
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- Production process of 2-amino-3,5-dibromobenzaldehyde
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The invention relates to the technical field of pharmaceutical chemicals, in particular to a production process of 2-amino-3,5-dibromobenzaldehyde. The method comprises the following steps: mixing iron powder and hydrochloric acid, adding an extracting agent and 3-nitro-o-dibromomethyl benzene, adjusting the pH value to 7-9 after the reaction is finished, conducting filtering, and separating the liquid to obtain an 3-amino-o-dibromomethyl benzene extraction reaction liquid; adding sulfuric acid into the reaction solution, conducting stirring, and conducting separating to obtain a 3-amino-o-dibromomethyl benzene sulfuric acid reaction solution; adding hydrobromic acid into the sulfuric acid reaction solution, dropwise adding bromogen and/or an oxidizing agent, controlling monobromine to be less than or equal to 0.2%, and adding chloroform to obtain a 2-amino-3,5-dibromodibromomethyl benzene organic solution; adding a dimethylamine aqueous solution and sodium bicarbonate into the organic solution, and separating the solution after the reaction to obtain a 2-amino-3,5-dibromobenzaldehyde chloroform reaction solution; and concentrating, refining and decoloring the chloroform reaction solution to obtain the 2-amino-3,5-dibromobenzaldehyde. The method provided by the invention can be used for industrially synthesizing the 2-amino-3,5-dibromobenzaldehyde, and the nitro waste material generated in the o-nitrobenzaldehyde production process can be utilized.
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Paragraph 0052-0053
(2021/09/29)
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- Repurposing an Aldolase for the Chemoenzymatic Synthesis of Substituted Quinolines
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Quinoline derivatives are important natural products and pharmaceuticals, but their synthesis can be challenging due to poor yields, harsh reaction conditions, and instability of starting materials. Here we report the chemoenzymatic synthesis of quinaldic acids under mild conditions using an aldolase, trans-o-hydroxybenzylidenepyruvate hydratase-aldolase (NahE, or HBPA). A series of 2-aminobenzaldehydes derived from reduction of the corresponding nitro analogue were reacted with pyruvate in the presence of NahE to give substituted quinolines in up to 93% isolated yield. This reaction differs from the aldol condensation catalyzed by NahE in vivo, instead resembling the heterocycle formation catalyzed by its homologue, dihydrodipicolinate synthase.
- Fansher, Douglas J.,Granger, Richard,Kaur, Satinderpal,Palmer, David R. J.
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p. 6939 - 6943
(2021/06/28)
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- Preparation method of ambroxol hydrochloride
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The invention relates to a preparation method of ambroxol hydrochloride, and the method comprises the following steps: carrying out aldehyde group protection on o-nitrobenzaldehyde, and reducing hydrazine hydrate in the presence of a catalyst NiCoB/TiO2 to obtain a compound 3; carrying out bromination reaction on the compound 3 under the action of molecular bromine and hydrogen peroxide, and carrying out deprotection to generate a compound 2; and carrying out aldehyde reductive amination reaction with trans-4-aminocyclohexanol under the action of catalysts NaBH (OAc) 3 and LiClO4, and salifying to obtain the ambroxol hydrochloride. The method has the advantages of mild conditions, simple steps, environmental friendliness, easily stored raw materials and high yield, and is suitable for industrial production.
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- Highly efficient and practical aerobic oxidation of alcohols by inorganic-ligand supported copper catalysis
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The oxidation of alcohols to aldehydes or ketones is a highly relevant conversion for the pharmaceutical and fine-chemical industries, and for biomass conversion, and is commonly performed using stoichiometric amounts of highly hazardous oxidants. The aerobic oxidation of alcohols with transition metal complex catalysts previously required complicated organic ligands and/or nitroxyl radicals as co-catalysts. Herein, we report an efficient and eco-friendly method to promote the aerobic oxidation of alcohols using an inorganic-ligand supported copper catalyst 1, (NH4)4[CuMo6O18(OH)6], with O2 (1 atm) as the sole oxidant. Catalyst 1 is synthesized directly from cheap and commonly available (NH4)6Mo7O24·4H2O and CuSO4, which consists of a pure inorganic framework built from a central CuII core supported by six MoVIO6 inorganic scaffolds. The copper catalyst 1 exhibits excellent selectivity and activity towards a wide range of substrates in the catalytic oxidation of alcohols, and can avoid the use of toxic oxidants, nitroxyl radicals, and potentially air/moisture sensitive and complicated organic ligands that are not commercially available. Owing to its robust inorganic framework, catalyst 1 shows good stability and reusability, and the catalytic oxidation of alcohols with catalyst 1 could be readily scaled up to gram scale with little loss of catalytic activity, demonstrating great potential of the inorganic-ligand supported Cu catalysts in catalytic chemical transformations.
- Wei, Zheyu,Ru, Shi,Zhao, Qixin,Yu, Han,Zhang, Gang,Wei, Yongge
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supporting information
p. 4069 - 4075
(2019/08/07)
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- Effective and Sustainable Access to Quinolines and Acridines: A Heterogeneous Imidazolium Salt Mediates C–C and C–N Bond Formation
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Quinoline and acridine derivatives have been prepared using a functionalized imidazolium salt as heterogeneous catalyst. Different ketones have been coupled with 2-aminobenzaldehydes and 2-aminoaryl ketones under solvent-free conditions, employing 1,3-bis(carboxymethyl)-imidazolium chloride as a catalyst. The protocol is simple and effective for the synthesis of a variety of nitrogen containing heterocycles (> 35 examples) with moderate to excellent yields (up to 96 %), being possible to perform the reaction in preparative scale. Additionally, 3-acetylquinolines have been transformed, under solvent-free conditions, into quinolyl chalcone derivatives by means of the same catalyst. Thus, the catalytic system mediates both reactions effectively in a tandem procedure. Furthermore, the catalyst is easily separated from the reaction mixture and can be reused without loss of activity (up to 8 cycles) which remarks its sturdiness. The E-factors are in the range of 14–23, both for the formation of quinolines and for the tandem reaction, which demonstrates the sustainability of the protocols described.
- Gisbert, Patricia,Albert-Soriano, María,Pastor, Isidro M.
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p. 4928 - 4940
(2019/08/12)
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- Highly practical and efficient preparation of aldehydes and ketones from aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst
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Herein, we divulge an efficient protocol for aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst, (NH4)5[IMo6O24]. The catalyst system is compatible with a wide range of groups and exhibits high selectivity, and shows excellent stability and reusability, thus serving as a potentially greener alternative to the classical transformations.
- Zhang, Mengqi,Zhai, Yongyan,Ru, Shi,Zang, Dejin,Han, Sheng,Yu, Han,Wei, Yongge
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supporting information
p. 10164 - 10167
(2018/09/13)
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- Method for synthesizing 2-amino-3,5-dibromobenzaldehyde through potassium bromide
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The invention discloses a method for synthesizing 2-amino-3,5-dibromobenzaldehyde through potassium bromide. The method comprises: (1) stirring and mixing ethanol, water and o-nitrobenzaldehyde, and heating until the solid o-nitrobenzaldehyde is completely dissolved; (2) adding reduced iron powder, adding 3-5 drops of hydrochloric acid in a dropwise manner, completely stirring, continuously heating to make the reaction system achieve a reflux temperature, and maintaining the stirring reaction; (3) carrying out suction filtration on the reaction solution, adding the mixed solution of bromine, potassium bromide and water to the obtained filtrate in a dropwise manner under stirring, and maintaining the temperature and carrying out the stirring reaction after completing the adding; and (4) adding excess saturated sodium bicarbonate solution to the reaction solution, completely stirring while precipitating the solid, and filtering to obtain the 2-amino-3,5-dibromobenzaldehyde. According to the present invention, the twp step reactions such as reducing and bromination are organically and integrally combined, such that the intermediate product o-aminobenzaldehyde obtaining process is eliminated so as to simplify the process and reduce the workload.
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Paragraph 0017; 0018; 0019; 0020-0023; 0025-0030; 0032-0037
(2018/04/02)
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- 2-amino-3,5-dibromobenzaldehyde synthesis method
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The present invention discloses a 2-amino-3,5-dibromobenzaldehyde synthesis method, wherein 2-amino-3,5-dibromobenzaldehyde is synthesized by using a reduction reaction product m-amino benzaldehyde and bromine as raw materials through a potassium bromide additive capable of increasing the utilization rate of bromine. According to the present invention, the 2-amino-3,5-dibromobenzaldehyde is synthesized through the potassium bromide additive capable of increasing the utilization rate of bromine, such that the yield is high, and the advantages of environmental protection and no pollution are provided.
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Paragraph 0018; 0019; 0020; 0021; 0022; 0023; 0024-0038
(2018/04/02)
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- Method for synthesizing 2-amino-3,5-dibromobenzaldehyde through hydrogen peroxide
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The invention discloses a method for synthesizing 2-amino-3,5-dibromobenzaldehyde through hydrogen peroxide, wherein the 2-amino-3,5-dibromobenzaldehyde is prepared and synthesized by using reducing reaction products such as o-aminobenzaldehyde and bromine as raw materials through hydrogen peroxide capable of improving the utilization rate of bromine. According to the present invention, the 2-amino-3,5-dibromobenzaldehyde is synthesized through the hydrogen peroxide additive capable of improving the utilization rate of bromine, such that the yield is high, and the method is pollution-free.
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Paragraph 0018-0024; 0027-0031; 0034-0038
(2018/04/02)
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- Versatile Barium and Calcium Imidazolium-Dicarboxylate Heterogeneous Catalysts in Quinoline Synthesis
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This article details the development of heterogeneous catalysts based on calcium and barium in combination with the organic linker 1,3-bis(carboxymethyl)imidazolium (bcmim). The linker and the materials from alkaline earth metals are easily prepared under very smooth conditions. The use of linkers with different counterions (Cl or Br) provided different materials. Calcium- and barium-based catalysts were successfully employed in the preparation of quinoline derivatives from ketones and 2-aminoarylaldehydes or 2-aminoarylketones. In general, barium-based catalysts provided better results than calcium, although the latter are an excellent complement for certain substrates. Thus, a notable feature of such catalysts is the possibility of accessing a variety of complementary heterogeneous catalytic systems, rendering the catalysis adaptive to the reactant.||||||.
- Albert-Soriano, María,Trillo, Paz,Soler, Tatiana,Pastor, Isidro M.
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supporting information
p. 6375 - 6381
(2017/12/01)
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- Method for synthesizing 2-amino-3,5-dibromobenzaldehyde through one-pot boiling
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The invention discloses a method for synthesizing 2-amino-3,5-dibromobenzaldehyde through one-pot boiling. The method comprises: (1) stirring and mixing ethanol, water and o-nitrobenzaldehyde, and heating until the solid o-nitrobenzaldehyde is completely dissolved; (2) adding reduced iron powder, adding 3-5 drops of hydrochloric acid in a dropwise manner, completely stirring, continuously heating until the reaction system achieves a reflux temperature, and maintaining the stirring reaction; (3) carrying out suction filtration on the reaction solution, adding bromine and 30% hydrogen peroxide to the obtained filtrate in a dropwise manner under stirring, and maintaining the temperature and carrying out the stirring reaction after completing the adding; and (4) adding excess saturated sodium bicarbonate solution to the reaction solution, completely stirring while precipitating a solid, filtering, and drying the organic layer by using anhydrous sodium sulfate to obtain the 2-amino-3,5-dibromobenzaldehyde. According to the present invention, the two step reactions such as reduction and bromination are organically and integrally combined, such that the intermediate product o-aminobenzaldehyde obtaining process is eliminated so as to simplify the process and reduce the workload.
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Paragraph 0018; 0019; 0020; 0021; 0022; 0023; 0024
(2018/04/02)
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- Efficient syntheses of the unknown quinolino[2,3- c ]cinnolines; Synthesis of neocryptolepines
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A facile, efficient, three-step protocol for the synthesis of the unknown quinolino[2,3-c]cinnoline 5 is introduced. In addition, a new approach for the preparation of the biologically active neocryptolepines 8 in good overall yields is described.
- Haddadin, Makhluf J.,Bou Zerdan, Raghida M.,Kurth, Mark J.,Fettinger, James C.
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supporting information; experimental part
p. 5502 - 5505
(2011/03/18)
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- Stability of bromhexine and the structure of its degradation products
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Refluxed acid or neutral aqueous solutions of Bromhexine (1) show four degradation products. 1 is decomposed at room temperature (20 deg C; 1 year) 1percent.Degradation products of crystalline 1 are not detectable in the temperature-moisture-test.Under normal storage conditions a 5-year stability for aqueuos solutions and a more than 10-year stability for crystalline 1 are estimated.Very small amounts of three degradation products were isolated by TLC.According to MS-, UV- and IR-analysis their structures are 3-cyclohexyl-6,8-dibromo-chinazoline-4-one (2a), 3-cyclohexyl-6,8-dibromo-chinazoline (2b) and 3-amino-4,6-dibromo-benzaldehyde (3).The structure of N-Methylcyclohexylamine is supposed for a further product.MS fragmentation and degradation mechanisms are discussed.
- Goeber, B.,Lisowski, Hannelore,Franke, P.
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- Process for the preparation of sulfur-containing N-benzyl-amino acids and esters
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A process for the preparation of sulfur-containing N-benzyl-amino acids of the formula STR1 wherein X and Y, which may be identical to or different from each other, are each hydrogen or halogen; R1 is hydrogen or alkyl of 1 to 4 carbon atoms; R2 is hydrogen, alkyl of 1 to 3 carbon atoms, carboxy-lower alkyl or acyl; R3 is hydrogen or acyl; and n is 1 or 2; which comprises the steps of converting anthranilic acid or a halogenated anthranilic acid into the corresponding aldehyde, reacting the aldehyde with a compound of the formula STR2 wherein R1, R2 and n have the meanings previously defined, to form the corresponding Schiff's base, reducing the said Schiff's base, and recovering the reaction product.
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- Pyrolysis of Aryl Azides. V. Characterization of Phenylazo, Benzoyl and Formyl as Neighbouring Groups
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The enhancements of thermolysis rate of azidobenzene produced by ortho phenylazo, benzoyl and formyl substituents are 21180, 70.0 and 22.8 at 393.2 K (decalin solutions).The same ortho substituents produce much smaller enhancements (169, 8.56 and 10.7 respectively) in the pyrolysis rate of 1-azido-2,4-dibromobenzene.These results are interpreted as steric effects on an electrocyclic thermolysis mechanism, and are not consistent with the alternative pathway of intramolecular 1,3-dipolar addition which continues to be advocated by Hall and Dolan.
- Dickson, Noel J.,Dyall, Leonard K.
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