摘要:
N-aryl-N'-alkyl-piperazines are obtained in a particularly simple manner, in good yields and in short reaction times when an aniline is reacted under pressure with an N-alkyl-bishydroxyethyl-amine in the presence of a strong acid.
摘要:
Process for the preparation of alkyl aryl ethers containing carboxyl groups which are suitable for the preparation of colour film couplers, or derivatives thereof, by reaction of aromatic alcohols with alkyl halides containing carboxyl groups or derivatives thereof and basic alkali metal or alkaline earth metal compounds, characterized in that the reaction is carried out in the melt of the aromatic alcohol.
摘要:
4-Hydroxybiphenyl is obtained in non-thixotropic form if a reaction mixture which is obtained by alkaline hydrolysis of biphenyl-4-sulfonic acid and contains 4-hydroxybiphenyl is heated at elevated pressure at above 115.degree. C. and at a pH from 0 to below 6.5.
摘要:
(2RS,3RS)-3-(2'-aminophenylthio)-2-hydroxy-3-(4"-methoxyphenyl)-propionic acid methyl ester, an important precursor for the preparation of the pharmaceutical active substance diltiazem, is obtained in a particularly high stereoselectivity and yield by addition of o-aminothiophenol onto 3-(4'-methoxyphenyl)-glycidic acid methyl ester if the reaction is carried out in the presence of alkali metal salts of weak acids in the presence of catalytic amounts of iron compounds.
摘要:
2-Chloroacrylonitrile is prepared in a particularly advantageous and readily industrially practicable manner by chlorinating acrylonitrile and then thermally cleaving the 2,3-diehloropropionitrile formed, by chlorinating acrylonitrile in the presence of a catalyst system comprising dimethylformamide and pyridine and/or pyridine derivatives and subjecting the resulting crude 2,3-dichloropropionitrile to thermal cleavage in the presence of the same catalyst system without the addition of further catalysts.
摘要:
4-Fluorothiophenol is obtained in outstanding purifies and yields if 4-fluorobenzenesulphonyl chloride is reacted with sodium hydrogen sulphite solution to give a solution of sodium 4-fluorobenzenesulphinate, this solution is reduced with sulphur dioxide to give 4,4'-difluorodiphenyl disulphide and finally this is reacted with sodium borohydride in a water-miscible inert organic solvent to give 4-fluorothiophenol (sodium salt). Free 4-fluorothiophenol can be isolated from the sodium salt solution by acidification.
摘要:
2-(Arylimino-methyl)-3-dialkylaminoacrylonitriles can be obtained by reaction of .beta.-anilino-acrylonitriles with ortho-formamides. They are suitable as starting substances for the preparation of 4-amino-5-iminiummethylene-2-pyrimidines or 4-amino-5-formyl-2-pyrimidines.
摘要:
Dialkyl dicarbonates are obtained particularly advantageously from halogenoformic esters by reaction with alkalis in the presence of water-immiscible organic solvents and in the presence of a catalyst, if the catalyst used is benzylalkyldimethylammonium halides. The catalyst is then particularly easy to separate off and to recycle from the reaction mixture.
摘要:
Mixtures consisting essentially of cyclohexylbiphenyls, dicyclohexylbenzenes, phenylbicyclohexyls and tercyclohexyls are outstandingly suitable as heat transfer media. The mixtures can be prepared from biphenyl and cyclohexanol in the presence of bleaching earths and subsequent hydrogenation.
摘要:
The halogen of a polyhalogenated aromatic compound can be transferred to a monohalogenated or nonhalogenated aromatic compound by reaction in the presence of ruthenium as the element or in the form of compounds and if desired with one or more metal compounds from subgroups I and II of the Periodic Table.