620-52-0Relevant articles and documents
Preparation method 3 - methyl -4 - isopropylphenol (by machine translation)
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Paragraph 0035-0038, (2020/10/04)
The invention discloses a preparation method of 3 - methyl -4 - isopropyl phenol, and belongs to the technical field of organic synthesis. The method comprises the following steps: (1) reacting m-cresol with a base under 5 - 20 °C conditions in water; (2) separating the intermediate A and the triphosgene in an organic solvent A, and separating the organic phase to obtain the intermediate C; (20 - 50 °C) the intermediate C is obtained by hydrolyzing the intermediate C in an organic solvent B under 3 conditions and separating the organic phase to obtain an intermediate C; (5 - 15 °C) the intermediate C is obtained by hydrolyzing the intermediate C in an organic solvent B in an organic solvent B in an organic 50 - 90 °C. solvent B in an organic solvent B and in an organic solvent B. The reaction is complete. 97% 4. The intermediate C is obtained by hydrolyzing the 70% intermediate C in an organic solvent B in an organic solvent B in an organic solvent B. (by machine translation)
The reactions of difluorodiiodomethane with nucleophiles
Guo, Yong,Chen, Qing-Yun
, p. 105 - 109 (2007/10/03)
Treatment of difluorodiiodomethane with phenoxides (ArO-) in DMF at room temperature gives ArOCF2I in 7-15%, the carbonates (ArOCO2Ar) being the major products, while with thiophenoxides affords difluoromethylene derivativ
Hydrolysis of aryl orthocarbonates by general acid catalyzed and spontaneous processes. Characterization of the water reaction of (ArO)3COAr′ and (ArO)3CN3
Kandanarachchi, Pramod,Sinnott, Michael L.
, p. 5592 - 5600 (2007/10/02)
Twenty-four aryl orthocarbonates of formula (Aro)4C, (ArO)2C(OAr′)2, or (ArO)3COAr′ have been made by coupling of the copper phenoxides with carbon disulfide, and their hydrolyses have been examined in 60% water-40% acetonitrile (I = 1.00 M, KCl) at 70.0 °C. Their hydrolysis by general acid catalyzed and, in the case of (ArO)3COAr′ when Ar′ = p-nitrophenyl and p-cyanophenyl, spontaneous processes yields aryl carbonates. The initial, rate-determining event for both processes is the cleavage of the bond between the central carbon and the least basic phenoxy group: with mixed orthocarbonates of phenols differing in pK by 6H4O)3C-O-P-C6H 4NO2 and (X-C6H4O)3C-O-p-C6H4CN where the σ value of X varies from -0.23 to 0.22 are 4-10 times slower than reactions of p-nitrophenyl tetrahydropyrans reported in the literature and give rise to nonlinear Hammett plots. However, plots against the pKa of X-C6H4OH are linear, and the derived β(reaction center) values indicate substantial buildup of positive charge on the central carbon atom. A similar plot is obtained for the spontaneous reactions of five azides (XC6H4O)3CN3 for which common ion inhibition experiments have been performed. The derived selectivities (M-1) of the tris(aryloxy)carbenium ion intermediates between azide ion and water vary from 8.5 × 103 to 6.6 × 103 as the σ value of X changes from -0.28 to 0.06. The lifetime of the tris(aryloxy)carbenium ion intermediates in water is therefore likely to be >10-6 s. The slow formation and slow hydrolysis of tris(aryloxy)carbenium ions suggests that (in the formation direction) development of conjugative stabilization lags behind carbon-oxygen bond cleavage and (in the hydrolysis direction) precedes carbon-oxygen bond formation. The stereochemistry of tetraaryl orthocarbonates immediately suggests reasons why this should be so.
Hydrolysis of orthocarbonates. Evidence for charge imbalance in the transition state for the general acid catalyzed process
Kandanarachchi, Pramod,Sinnott, Michael L.
, p. 5601 - 5606 (2007/10/02)
Catalytic constants have been measured for the hydrolysis of a range of aryl orthocarbonates, in which both the leaving group and trioxocarbenium ion moiety have been systematically varied, by neutral carboxylic acids (trichloroacetic, difluoroacetic, dichloroacetic, malonic, chloroacetic, and acetic) at 70.0°C in 60% water-40% acetonitrile, I = 1.0 M (KCI). Curvature cannot be detected in Br?nsted plots involving carboxylic acids only, but inclusion of the point for H3O+ suggests downward curvature (i.e. px ≥ 0). β1g Plots are curved downward (i.e. py′ = -?β1g/?pK1g > 0). Substitutent effects in the tris(aryloxy)carbenium ion fragment were quantitated by use of the experimental aqueous pKa alues of the phenol (pKrc), rather than Hammett σ values, since this gave better correlations for the spontaneous reactions (Kandanarachchi, P.; Sinnott, M. L. J. Am. Chem. Soc., preceding paper in this issue). Cross coefficients are large and not constant: pxy′ (measured as ?α/?pK1g rather than -?β1g/?pKHA) varies from 0.26 for (PhO)3C+ to 0.16 for (PMeOC6H4O)3C+. Likewise,pxy (measured as -?α/?pKrc rather than -?βrc/?pKHA) experiences large changes with the leaving group pK. Data to estimate pyy′ (?βrc/?pK1g) are more limited, but it too changes with the pKa of the catalyzing acid. These data indicate that a two-dimensional More O'Ferrall-Jencks diagram, with one axis representing both C-O cleavage and the ability of substituents in the tris(aryloxy)carbenium ion moiety to sense positive charge development, is inadequate to represent this reaction: separate axes are required for carbon-oxygen bond cleavage and development of carbon-oxygen double-bond character.
