摘要:
Ethynylcyclopropane is prepared from (1,1-dimethoxyethyl)cyclopropane by a two-stage elimination of methanol. Ethynylcyclopropane is an intermediate in the synthesis of pharmaceutically active ingredients, for example, antiviral agents.
摘要:
The invention relates to a method for the production of L-carnitine, wherein a chiral β-lactone carnitine precursor is obtained by a [2+2] cycloaddition of ketene with an aldehyde X—CH2—CHO, wherein X is selected from Cl, Br, I and trimethylamine, in the presence of a chiral catalyst.
摘要:
The present invention relates to a process for the selective preparation of acetaldehyde, characterized in that acrolein and one or more ammonium salts dissolved in water are reacted continuously under high pressures and at temperatures of 300-400° C.
摘要:
Process for removing hydrogen cyanide from ethanedinitrile by contacting hydrogen cyanide-containing ethanedinitrile with an organic reagent under formation of a covalent bond.
摘要:
A method for the production of 6,6,6-trihalo-3,5-dioxohexanic acid esters of formula (I): in addition to the enols thereof and E and Z isomers, wherein X independently represents fluorine, chlorine or bromine and R1 represents alkyl, cycloalkyl, aryl or aralkyl. A method for the production of enol ethers of formula (Ib): and the enols thereof (E and Z isomers) wherein X and R1 have the above-mentioned meanings.
摘要:
A method for the production of 6,6,6-trihalo-3,5-dioxohexanoic acid esters of formula (I): in addition to the enols thereof and E and Z isomers, wherein X independently represents fluorine, chlorine or bromine and R1 represents alkyl, cycloalkyl, aryl or aralkyl. A method for the production of enol ethers of formula (Ib): and the enols thereof (E and Z isomers) wherein X and R1 have the above-mentioned meanings.
摘要:
Compounds of the general Formula: in which R1 and R2 are at each occurrence independently hydroxyl, C1-6-alkyl, C1-6-alkoxy, halogen, phenyl or phenoxy; R2 is hydroxyl, C1-6-alkyl, C1-6-alkoxy, halogen, phenyl or phenoxy; R3 is C1-6-alkyl; m is an integer from 0 to 4; and n is an integer from 0 to 5.
摘要:
The invention relates to a novel method for producing robenidine and salts thereof of the general formula wherein X denotes a halogen atom. The method uses hydrazine hydrate and a cyano compound YCN as the starting materials, which are first reacted to projuce a diaminoguanidine of the general formula wherein Y denotes a halogen atom or tosyl. This diaminoguanidine is then converted directly, without isolation, by reacting with a p-halobenzaldehyde of the general formula IV to produce the robenidine and salts thereof of general formula I.
摘要:
5-Oxaspiro[2.4]heptan-6-one: ##STR1## is obtained from [3-(hydroxymethyl)oxetan-3-yl]acetonitrile by reaction with hydrogen bromide and then cyclizing the intermediate product 4,4-bis(bromomethyl)dihydro-2-furanone with zinc. 5-Oxaspiro[2.4]heptan-6-one is an intermediate product for the production of leukotriene antagonists.
摘要:
Enolate salts of 4-fluoro-2-hydroxymethylene-3-oxobutyrates of formula wherein R1 is C1-10 alkyl, R2 and R3 are independently hydrogen or fluorine, M is an alkali or alkaline earth metal, and n is 1 or 2, are prepared from enolate salts of the corresponding 4-fluoro-3-oxobutyrates and carbon monoxide. The enolate salts of formula I can be alkylated or acylated to obtain the corresponding enol ethers and esters. The 4-fluoro-3-oxobutyrate starting material can be prepared from 1,1-difluoroethyl methyl ethers by SbF5-catalyzed fluoromethane elimination followed by halogen exchange with lithium chloride, reacting the thus obtained fluoroacetyl chloride with ketene and quenching with the appropriate alcohol R1—OH.