- Friedel–Crafts Type Methylation with Dimethylhalonium Salts
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The dimethylchloronium salt [Me2Cl][Al(OTeF5)4] is used to methylate electron-deficient aromatic systems in Friedel–Crafts type reactions as shown by the synthesis of N-methylated cations, such as [MeNC5F5]+, [MeNC5F4I]+, and [MeN3C3F3]+. To gain a better understanding of such fundamental Friedel–Crafts reactions, the role of the dimethylchloronium cation has been evaluated by quantum-chemical calculations.
- H?mmerling, Sebastian,Vo?nacker, Patrick,Steinhauer, Simon,Beckers, Helmut,Riedel, Sebastian
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p. 14377 - 14384
(2020/10/12)
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- Two-step regioselective synthesis of 1,2-difluorobenzenes from chlorotrifluoroethylene and buta-l,3-dienes
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The gas-phase copyrolysis of chlorotrifluoroethylene with buta-1,3-diene, penta-1,3-diene, or isoprene in a flow reactor at 440–480°C gave 4-chloro-4,5,5-trifluorocyclohex-1-enes. The latter treated with aqueous KOH under condition of phase-transfer catalysis were selectively converted into 1,2-difluorobenzene, 2,3-difluorotoluene, or 3,4-difluorotoluene.
- Lipkind, M. B.,Nefedov, O. M.,Volchkov, N. V.
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- LIQUID CRYSTALLINE COMPOUND HAVING DIBENZOTHIOPHENE RING, LIQUID CRYSTAL COMPOSITION AND LIQUID CRYSTAL DISPLAY ELEMENT
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PROBLEM TO BE SOLVED: To provide a liquid crystalline compound satisfying at least one of physical properties such as high stability to heat or light, a high clear point, a low minimum temperature of a liquid crystal phase, small viscosity, appropriate optical anisotropy, negatively large dielectric anisotropy, an appropriate elastic constant and good compatibility with other liquid crystalline compounds, a liquid crystal composition containing the compound, and a liquid crystal display element containing the composition. SOLUTION: The compound is represented by formula (1), and the liquid crystal composition contains the above compound. In the formula, R1 and R2 represent an alkyl having 1 to 16 carbon atoms, or the like; A1 to A2 represent 1,4-cyclohexylene or the like; Z1 and Z2 represent a single bond or the like; m1 and n1 represent 0, 1 or 2; W represents -S- or the like; X represents H or F; and Y1 to Y4 represent H or a methyl. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
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Paragraph 0167-0168
(2020/10/27)
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- Reactions of aromatic compounds with xenon difluoride
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Reactions of substituted benzenes C6H5R (R = Me, F, Cl, Br, CF3, NO2) with xenon difluoride in the presence of boron trifluoride–diethyl ether complex in weakly acidic (1,1,1,3,3-pentafluorobutane) and weakly basic media (acetonitrile) have been studied. These reactions lead to the formation of fluorobenzene derivatives FC6H4R (isomer mixture) together with isomeric difluorobenzenes and fluorinated and non-fluorinated biphenyls. The results have been compared with previously reported data obtained in other solvents using other catalysts.
- Bardin,Adonin, N. Yu.
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p. 1400 - 1407
(2016/11/29)
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- Method of preparing fluoroaromatic compounds
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The present invention provides a method of preparing ortho-difluorobenzene derivatives, which comprises (a) providing a mixture of cyclohexenes by reacting chlorotrifluoroethylene (CTFE) and 1,3-diene in a flow reactor and distilling the resultant, and (b) dehydrohalogenating the mixture of cyclohexenes with a phase transition catalyst in the presence of alkali metal hydroxide at temperature range of 40 to 150 °C without using any organic solvent. The distillate having low boiling point, which is obtained during distillation of the resultant, is recycled into the flow reactor. The present invention also provides a method of preparing 2-chloro-4,5-difluorobenzoic acid, which comprises (a) providing a mixture of 4-chloro-1-methyl-4,5,5-trifluorocyclohexene and 5-chloro-1-methyl-4,4,5-trifluorocyclohexene by reacting chlorotrifluoroethylene (CTFE) and isoprene and distilling the resultant, (b) dehydrohalogenating said mixture in the presence of alkali metal hydroxide and a phase transition catalyst to form 3,4-difluorotoluene, (c) reacting said 3,4-difluorotoluene with chlorine gas without using any organic solvent to form 2-chloro-4,5-difluorotoluene, (d) photo-reacting said 2-chloro-4,5-difluorotoluene with chlorine gas under a lighting mercury lamp without using any organic solvent to form 2-chloro-4,5-difluorobenzotrichloride, and (e) reacting said 2-chloro-4,5-difluorobenzotrichloride with aqueous acid solution without using any organic solvent. The present invention also provides a method of preparing 2-chloro-4,5-difluorobenzoyl chloride by reacting the 2-chloro-4,5-difluorobenzotrichloride of step (e) above with zinc oxide.
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- Method of preparing fluoroaromatic compounds
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The present invention provides a method of preparing ortho-difluorobenzene derivatives, which comprises (a) providing a mixture of cyclohexenes by reacting chlorotrifluoroethylene (CTFE) and 1.3-diene in a flow reactor and distilling the resultant, and (b) dehydrohalogenating the mixture of cyclohexenes with a phase transition catalyst in :he presence of alkali metal hydroxide at temperature range of 40 to 150° C. without using any organic solvent. The distillate having low boiling point, which is obtained during distillation of the resultant, is recycled into the flow reactor. The present invention also provides a method of preparing 2-chloro-4,5-difluorobenzoic acid, which comprises (a) providing a mixture of 4-chloro-1-methyl-4,5,5-trifluorocyclohexene and 5-chloro-1-methyl-4,4,5-trifluorocyclohexene by reacting chlorotrifluoroethylene (CTFE) and isoprene and distilling the resultant. (b) dehydrohalogenating said mixture in the presence of alkali metal hydroxide and a phase transition catalyst to form 3,4-difluorotoluene, to reacting said 3,4-difluorotoluene with chlorine gas without using any organic solvent to form 2-chloro-4,5-difluorotoluene, (d) photo-reacting said 2-chloro-4,5-difluorotoluene with chlorine gas under a lighting mercury lamp without using any organic solvent to form 2-chloro-4,5-difluorobenzotrichloride, and (e) reacting said 2-chloro-4,5-difluorobenzotrichloride with aqueous acid solution without using any organic solvent. The present invention also provides a method of preparing 2-chloro-4,5-difluorobenzoyl chloride by reacting the 2-chloro-4,5-difluorobenzotrichloride of step (e) above with zinc oxide.
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- Intermediates for preparing 1,4-dihydro-4-oxo-quinoline-3-carboxylic acid esters
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Compounds of the formula: wherein Y is OR1, fluoro, chloro, methyl, R1, and R3 are independently selected from hydrogen and C1-C4 alkyl, R2 is C1-C4 alkyl and X is fluoro, chloro or bromo, with the proviso that when Y is OH, X cannot be bromo and with the proviso that X can be fluoro only if R2 is methyl.
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