摘要:
A new process for preparing calcium salts of 3-hydroxy-3-methylbutyric acid is described. Lactones obtained from ketene and acetone are hydrolyzed in selective and scalable manners. The 3-hydroxy-3-methylbutyric acid or its calcium salts are useful in preparations for inhibiting protein depletion or as immuno-stimulating feedstuff additives for mammals.
摘要:
Disclosed are 3-cyanopyridinium tricyanomethanides of formula (I), wherein n is an integer from 2 to 10 and R is hydrogen or -CN, and a process for the preparation thereof. The 3-cyanopyridinium tricyanomethanides are useful e. g. as selective solvents in the separation of alkene-alkane mixtures.
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.
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:
The invention provides a process for the preparation of compounds of formula (I), wherein wherein R 1 is C 1-6 -alkyl or C 3-6 -cycloalkyl, R 2 is selected from the group consisting of hydrogen, C 1-6 -alkyl and C 3-6 -cycloalkyl, and Q 1 is selected from the group consisting of halogen, cyano and -CO-R 3 , wherein R 3 is selected from hydrogen, hydroxy, C 1-6 -alkoxy, C 3-8 -cycloalkyloxy, aryloxy, C 1-6 -alkylamino, aryl-(C 1-6 -alkyl)amino and di-C 1-6 -alkylamino, comprising the step of reacting a corresponding o -nitroaniline with an aldehyde R 2 -CHO or an equivalent thereof in the presence of a reducing agent.
摘要:
The invention discloses a method for preparation of mononitrated aromatic compounds in a liquid-liquid biphasic solvent system with aqueous nitric acid as one phase and ionic liquids (ILs) as the second phase, wherein the nitric acid is exchanged batchwise or continuously during the reaction.
摘要:
A new process for preparing calcium salts of 3-hydroxy-3-methylbutyric acid is described. Lactones obtained from ketene and acetone are hydrolyzed in selective and scalable manners. The 3-hydroxy-3-methylbutyric acid or its calcium salts are useful in preparations for inhibiting protein depletion or as immuno-stimulating feedstuff additives for mammals.
摘要:
The invention relates to a method for the production of L-carnitine, wherein a β- lactone, which is a 4-(halomethyl)oxetane-2-one, is converted into carnitine with trimethylamine (TMA), wherein the β-lactone is not subjected to a basic hydrolysis step before being contacted with the trimethylamine. The invention also relates to a carnitine having a unique impurity profile.
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-CH 2 -CHO, wherein X is selected from CI, Br, I and trimethylamine, in the presence of a chiral catalyst.
摘要:
Enolate salts of 4-fluoro-2-hydroxymethylene-3-oxobutyrates of formula wherein R 1 is C 1-10 alkyl, R 2 and R 3 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 SbF 5 -catalyzed fluoromethane elimination followed by halogen exchange with lithium chloride, reacting the thus obtained fluoroacetyl chloride with ketene and quenching with the appropriate alcohol R 1 -OH.