摘要:
N,N-Diaryl-ureas of the formulaR.sup.1 --NR.sup.2 --CO--NH--R.sup.3whereinR.sup.1 and R.sup.2 denote aryl andR.sup.3 denotes alkyl, aralkyl or aryl, can be prepared by a process in which a diarylamine of the formulaR.sup.1 --NH--R.sup.2is reacted with an isocyanate of the formulaR.sup.3 --NCOwherein R.sup.1, R.sup.2 and R.sup.34 have the above meaning, in the presence of acid compounds and in the presence or absence of an inert solvent and/or diluent at elevated temperature.
摘要:
2,4- or 2,6-dihalogeno-aniline can be prepared by reacting an amino-benzoic acid ester of the formula ##STR1## in which R.sup.1, R.sup.2 and R.sup.3 have the meanings indicated in the description, with 2-2.5 moles of a chlorinating or brominating agent in an inert reaction medium at a temperature of 40.degree.-160.degree. C. and subsequently hydrolyzing and decarboxylating the dihalogenated amino-benzoic acid ester.
摘要:
3-Chloro-3'-nitro-4'-methoxybenzophenone with substantially lower contents of dinitro derivatives than hitherto is obtained if 3-chloro-4'-methoxybenzophenone is nitrated in from 65 to 85% strength by weight sulfuric acid with nitric acid at temperatures in the range from -20.degree. to +60.degree. C.
摘要:
2,3-dichloro-nitrobenzene can be prepared by nitration of 1,2-dichlorobenzene using an anhydrous mixture of phosphoric acid, sulphuric acid and nitric acid. The conditions according to the invention displace the ratio of 2,3,-dichloro-nitrobenzene and 3,4-dichloro-nitrobenzene in favor of the 2,3-isomer.
摘要:
Described herein is a process for the preparation of 3,4-diaminobenzenesulphonic acid, characterized in that 1,2-diaminobenzene is reacted with anhydrous sulphuric acid which optionally comprises SO3 in up to stoichiometric amount, at a temperature in the range from 100 to 160° C. with stirring for a reaction time of from 1 to 20 hours; water or ice is added to the reaction mixture, optionally with cooling, up to a sulphuric acid concentration in the range from 30 to 75% by weight, based on the total mixture; the 3,4-diaminobenzenesulphonic acid precipitated out of the reaction mixture is filtered off, optionally washed with dilute sulphuric acid and worked up.
摘要:
2- and 3-Nitrobenzaldehydes suitable for use as intermediates for the preparation of pharmaceuticals are obtained in a simple manner and without risk of uncontrolled decompositions by distilling mixtures of nitrobenzaldehyde isomers at bottom temperatures of at most 200.degree. C. in the presence of monomeric and/or polymeric aromatic amines and/or phenols and/or N- and S-containing phenothiazines.
摘要:
A process for the preparation of 2-phenylbenzimidazole-5-sulphonic acid, characterized in that 3,4-diaminobenzenesulphonic acid is reacted at a pH between 4 and 7 in aqueous solution with 0.9 to 1.5 mol of benzaldehyde per mole of 3,4-diaminobenzenesulphonic acid and with 1.0 to 3.0 mol of SO2 per mole of 3,4-diaminobenzenesulphonic acid, or an agent which comprises 1.0 to 3.0 mol of SO2 per mole of 3.4-diaminobenzenesulphonic acid, is described.
摘要翻译:一种制备2-苯基苯并咪唑-5-磺酸的方法,其特征在于3,4-二氨基苯磺酸在水溶液中的pH值为4-7之间,每摩尔3,4-二氨基苯磺酸使用0.9至1.5摩尔苯甲醛, 每摩尔3,4-二氨基苯磺酸1.0〜3.0摩尔的SO 2 N 2,或每摩尔3,4-二氨基苯磺酸1.0〜3.0摩尔的SO 2原子的试剂, 描述了3.4-二氨基苯磺酸。
摘要:
5-Fluoro-2-nitrobenzoic acid having low contents of 3-fluoro-2-nitro-benzoic acid is prepared in a simple manner by nitrating 3-fluorobenzoic acid in an anhydrous medium using an anhydrous nitrating acid and isolating and purifying 5-fluoro-2nitro-benzoic acid, by taking 7.5 to 15 parts by weight of water, based on 1 part by weight of 3-fluorobenzoic acid used, introducing the reaction mixture reacted to exhaustion into this volume of water taken, filtering off the precipitate formed and washing it with water.