- NEW METHOD FOR PREPARING 2-TERT-BUTYL-4-METHOXYPHENOL AND NEW CRYSTAL FORM THEREOF
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The present invention relates to a stable crystal form, i.e. form A, of 2-tert-butyl-4-methoxyphenol, and to a new preparation method for the 2-tert-butyl-4-methoxyphenol; and the use of the 2-tert-butyl-4-methoxyphenol and the stable crystal form thereof, i.e. form A, in preparing antitumor drugs or immunomodulator drugs. The stable crystal form, i.e. form A, as expressed by a powder X-ray diffraction pattern in an angle of 2θ, using Cu-Kα radiation, has at least 3 absorption peaks selected from the following positions: 6.27±0.10, 6.94±0.10, 12.27±0.10, 13.36±0.10, 14.01±0.10, 14.79±0.10, 15.31±0.10, 17.05±0.10, 18.30±0.10, 19.00±0.10, 20.47±0.10, 20.98±0.10, 22.37±0.10, 23.68±0.10, 24.55±0.10, 25.37±0.10, 30.83±0.10, 33.12±0.10, 40.50±0.10, 42.81±0.10.
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Paragraph 0041; 0039; 0040
(2021/10/15)
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- Method for synthesizing butyl hydroxy anisd
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The invention discloses a method for synthesizing butyl hydroxy anisd (BHA). The BHA is synthesized by taking tert-Butylhydroquinone (TBHQ) and dimethyl carbonate (DMC) as raw materials and taking self-made double alkali metals as catalysts. The conversion ratio of the TBHQ is 28-40%, the selectivity of the produced target product 3-tert-butyl-4-hydroxy anisole (3-BHA) is 84-100%, and when the catalyst is repeatedly used in five batches, the catalytic activity is not reduced. The method disclosed by the invention has the advantages that the BHA prepared by catalysis of the self-made double alkali metal catalyst is high in selectivity, the catalyst can be simply filtered and repeatedly used, and the used raw material dimethyl carbonate is a green reagent without any environmental pollution.Moreover, the unreacted TBHQ and dimethyl carbonate can be directly recycled for the next reaction, the amount of reaction by-products is small, the reaction conditions are relatively mild, the synthesizing cost is low, and the 3-BHA with relatively high purity (purity of being greater than or equal to 98%) can be obtained. Therefore, the method has wide industrialized application prospects.
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Paragraph 0022-0050
(2018/08/03)
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- Hydrolysis stability of bidentate phosphites utilized as modifying ligands in the Rh-catalyzed n-regioselective hydroformylation of olefins
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The stability of ligands and catalysts is an almost neglected issue in homogeneous catalysis, but it is crucial for successful application of this methodology in technical scale. We have studied the effect of water on phosphites, which are the most applied cocatalysts in the n-regioselective homogeneous Rh-catalyzed hydroformylation of olefins. The stability of the bidentate nonsymmetrical diphosphite L1, as well as its two monophosphite constituents L2 and L3, toward hydrolysis was investigated by means of in situ NMR spectroscopy under similar conditions as applied in industry. Hydrolysis pathways, intermediates, and kinetics were clarified. DFT calculations were used to support the experimentally found data. The acylphosphite unit L2, which reacts with water in an unselective manner, was proven to be much less stable than the phenolphosphite L3. The stability of the bidentate ligand L1 can be therefore mainly attributed to its phenolphosphite moiety. With an excess of water, the hydrolysis of L1 and L2 as well as their Rh-complexes is first-order with respect to the phosphite. Surprisingly, coordination to Rh significantly stabilizes the monodentate ligand L2, while in strong contrast, the bidentate ligand L1 decomposes faster in the Rh complex. NMR spectroscopy provided evidence for the existence of species from decomposition of phosphites, which can likewise coordinate as ligands to the metal. Electron-withdrawing groups in the periphery of the acylphosphite moiety decrease the stability of L1, whereas 3,5-disubstituted salicylic acid derivatives with bulky groups showed superior stability. These modifications of L1 also give rise to different catalytic performances in the n-regioselective hydroformylation of n-octenes and 2-pentene, from which the 3,5-di-t-butyl-substituted ligand offered a higher n-regioselectivity accompanied by a lowering of the reaction rate in comparison to the parent ligand L1.
- Zhang, Baoxin,Jiao, Haijun,Michalik, Dirk,Klo?, Svenja,Deter, Lisa Marie,Selent, Detlef,Spannenberg, Anke,Franke, Robert,B?rner, Armin
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p. 7554 - 7565
(2018/05/23)
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- Organochalcogen substituents in phenolic antioxidants
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Little is known about the ED/EW character of organochalcogen substituents and their contribution to the O-H bond dissociation enthalpy (BDE) in phenolic compounds. A series of ortho- and para-(S,Se,Te)R-substituted phenols were prepared and investigated by EPR, IR, and computational methods. Substituents lowered the O-H BDE by >3 kcal/mol in the para position, while the ortho-effect was modest due to hydrogen bonding (～3 kcal/mol) to the O-H group.
- Amorati, Riccardo,Pedulli, Gian Franco,Valgimigli, Luca,Johansson, Henrik,Engman, Lars
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scheme or table
p. 2326 - 2329
(2010/07/20)
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- Photochemistry of aryl tert-butyl ethers in methanol: The effect of substituents on an excited state cleavage reaction
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The photolysis of a set of 10 substituted aryl tert-butyl ethers, 8a-j, in methanol gave, as the major product, the corresponding phenol along with tert-butyl-substituted phenols resulting from photo-Fries reaction. The corresponding 4-cyanophenyl 1-adamantyl ether, 9, also gave 1-meth-oxyadamantane 16 (16%), indicating that, at least for this ether, some of the products were ion-derived. Quenching studies with 2,3-dimethylbutadiene for the tert-butyl ethers indicated that these reactions were occurring from the singlet excited state. Rate constants for the reaction, obtained from quantum yields and singlet lifetimes, were found to correlate reasonably well with σhv values, ρ = -0.77 (r = 0.975), a result that is unexpected for a reaction where the polarity of the bond breaking in the transition state is expected to be -O(δ-)···C(δ+).
- DeCosta,Bennett,Pincock,Pincock,Stefanova
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p. 4162 - 4168
(2007/10/03)
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- Color-stabilized basic monomers, process for producing the same and method for handling the same
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Color-stabilized basic monomers are provided. Said basic monomers are obtained by adding, to a basic monomer ?e.g. an N,N-dialkylaminoalkyl (meth)acrylate or an N,N-dialkylaminoalkyl (meth)acrylamide!, at least one member selected from the group consisting of amido group-containing compounds, phosphorous acid esters, phosphoric acid esters and phosphines and at least one phenol compound represented by the general formula: STR1 wherein R5, R6, R8 and R9 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and R7 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. The color-stabilized basic monomers are more resistant to coloration when they are handled under such conditions that the oxygen concentration in the gas phase contacting therewith is 0.01 to 10% by volume.
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- Activation of a Metal-Axial Ligand Bond in Aluminum Porphyrin by Visible Light
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Irradiation with visible light induced a remarkable effect on the reactivity of a metal-carbon bond in (tetraphenylporphinato)aluminum methyl in the nucleophilic substitution reaction with protic compounds such as phenol.A similar photoacceleration effect was also observed in the reversible ligand exchange of (tetraphenylporphinato)aluminum phenoxide with phenol.As for the former reaction, comparable quantum yields were observed upon irradiation at the Soret band and at the Q-band.
- Hirai, Yasuhiro,Murayama, Hideki,Aida, Takuzo,Inoue, Shohei
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p. 7387 - 7390
(2007/10/02)
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- Preparation of 2-t-butyl-4-alkoxy- and 4-hydroxyphenols
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Tertiary alkyl phenyl ethers may be induced to undergo thermal rearrangement on an alumina catalyst to afford the isomeric ortho-t-alkylphenol. Such rearrangement generally occurs under milder conditions than does the alkylation of a phenol with an olefin using the same alumina as an alkylating catalyst. The rearrangement remains regioselective even when the phenyl ring bears an alkoxy group, hence affords a good preparative route to such materials as 2-t-butyl-4-methoxyphenol.
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- Process for preparing monoalkylethers of hydroquinone and its derivatives
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A method for preparing monoalkylethers of hydroquinone and of substituted hydroquinones of general formula STR1 in which R is an alkyl group and R1 is hydrogen or an alkyl group, wherein a hydroquinone compound of general formula STR2 is reacted with an alcohol or formula R-OH in the presence of transition metal salts, either in the presence or in the absence of air or oxygen.
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- Phenol transalkylation process
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Phenols having an unsubstituted ortho position are transalkylated in the ortho position by mixing them with an ortho-alpha-branched alkylphenol (e.g., 2,6-di-sec-butylphenol) and an aluminum phenoxide catalyst and heating the mixture to 100°-350°C., preferably in a closed system and in the presence of olefin corresponding in structure to the ortho-alpha-branched alkyl group.
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