摘要:
Cis-R-dioxo-benzylpyrrolopiperidine is racemized in a particularly advantageous manner by treating it with a substoichiometric amount of base, preferably at temperatures below about 40° C.
摘要:
The present invention relates to a process for the enantiomeric enrichment of cis-8-benzyl-7,9-dioxo-2,8-diazabicyclo[4.3.0]nonane with the aid of continuous countercurrent chromatography, which is also described as SMB chromatography (SMB=simulated moving bed). In a further aspect, the invention relates to a process for the preparation of (1S,6R)-8-benzyl-7,9-dioxo-2,8-diazabicyclo[4.3.0]nonane using the aforementioned process, which furthermore includes a racemization step.
摘要:
The present invention relates to a process for the enantiomeric enrichment of cis-8-benzyl-7,9-dioxo-2,8-diazabicyclo[4.3.0]nonane with the aid of continuous countercurrent chromatography, which is also described as SMB chromatography (SMB=simulated moving bed).In a further aspect, the invention relates to a process for the preparation of (1S,6R)-8-benzyl-7,9-dioxo-2,8-diazabicyclo[4.3.0]nonane using the aforementioned process, which furthermore includes a racemization step.
摘要:
Piperidines are prepared in an advantageous manner by catalytic hydrogenation of activated pyridines in the presence of palladium catalysts if the palladium catalyst is palladium-on-carbon and the solvents are aromatic hydrocarbons.
摘要:
5-Fluorotoluene-2,4-disulphochloride is prepared by chlorosulphonation of 3-fluorotoluene by first reacting the 3-fluorotoluene with chlorosulfuric acid and then with an inorganic acid chloride at temperatures up to 130.degree. C. until the evolution of gas is complete, and then heating the reaction mixture at temperatures of up to 200.degree. C. and, after the completion of the gas evolution, reacting the product at a lower temperature with further inorganic acid chloride, or reacting the 3-fluorotoluene with powerful sulphonating agents at an elevated temperature, if appropriate in the presence of inert solvents and/or diluents, to give the corresponding disulphonic acid and then treating the disulphonic acid with inorganic acid chlorides.
摘要:
Ortho-substituted fluoroaromatic compounds are prepared by reaction of corresponding anilines, which are substituted in the o-position, with alkyl nitrites in the presence of alcohols and/or ethers and in the presence of boron trifluoride or boric acid esters and hydrogen fluoride, and by isolation and decomposition of the diazonium tetrafluoborate produced.
摘要:
An improved process for preparing carbamic ester derivatives of the general formula (1) by reaction with carbon monoxide and water in the presence of a palladium catalyst is provided.
摘要:
The invention relates to a special two-step method for producing amines on the basis of amides by reacting them with halides or hypohalites in an aqueous solution in a Hofmann degradation reaction. The amide is reacted in an alkaline solution and/or suspension with halides or hypohalites and the reaction mixture obtained in step 1 is added to an aqueous alkaline solution having a temperature of at least 40° C.
摘要:
Cyclopropanecarboxamide can be prepared by reaction of a cyclopropanecarboxylic ester with NH.sub.3, in which the ester alcohol has 4-8 C atoms and can be straight-chain or branched and which process is carried out in the presence of catalytic amounts of an alkali metal alcoholate of a monohydric C.sub.1-C.sub.8 alcohol at 60.degree.-200.degree. C. in the absence of a hydrocarbon solvent.
摘要:
The present invention relates to a novel process for preparing 8-methoxy-3-quinolonecarboxylic acids which are antibiotics having potent antibacterial action.