摘要:
Difluoropropionic acid and derivatives thereof are prepared by bringing elemental fluorine in the presence of a solvent into an addition reaction with appropriate acrylic acids or derivatives thereof. In this way, it is also possible to obtain novel fluorinated esters of 2,3-difluoropropionic acid.
摘要:
.alpha.-Fluoro-substituted N-acryloylamino acid derivatives of the formula ##STR1## are used to make polymers optionally for chromatographic resolution of racemates into their enantiomers. The fluorine atom improves performance in many instances.
摘要:
.alpha.-Fluoro-substituted N-acryloylamino acid derivatives of the formula ##STR1## are used to make polymers optionally for chromatographic resolution of racemates into their enantiomers. The fluorine atom improves performance in many instances.
摘要:
The present invention relates to the use of optically active polymers of N-acryloyl-phenylalanine neomenthylamide as such, in crosslinked form and/or in carrier-bonded form as stationary phases for the chromatographic separation of enantiomers of lactones.
摘要:
The invention relates to the preparation and use as catalysts of diphosphines of the formula (I) in which R is C6-C14-aryl or C4-C13-heteroaryl containing 1 to 3 heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur, wherein the aryl and heteroaryl radicals may optionally be substituted by halogen, C1-C6-alkyl, C1-C6-alkoxy, and/or trimethylsilyl, and R1 to R4, independently of one another, are each hydrogen, C1-C10-alkyl, C1-C10-alkoxy, F, Cl, or Br.
摘要:
An optically active N-(meth)acryloyl amino acid amide of the formula ##STR1## in which R is hydrogen or methyl,R.sub.1 represents an optionally substituted alkyl, cycloalkyl, aralkyl, aryl or heteroaryl radical,R.sub.3 represents hydrogen or denotes together with R.sub.1 a tri- or tetramethylene group;X denotes oxygen or a NR.sub.4 -group wherein R.sub.4 represents hydrogen or alkyl or denotes together with R.sub.2 and the nitrogen atom a 5- to 7-membered ring which ring is optionally substituted by the group COO-alkyl (1-6 carbon atoms) or by one or two alkyl radicals (1-4 carbon atoms) andR.sub.2 denotes a strongly space-filling hydrocarbon radical.The amide is polymerized and optionally bound to a support such as silica, and can then be used for the chromatographic separation of racemic mixtures of pharmacologically active compounds.
摘要:
A crane is provided which comprises a hoisting mechanism, which comprises a hoisting rope and a hoisting rope winch. A winch drive for the hoisting rope or a torque-limiting coupling connected between said winch drive and said winch is so controlled that in a period of time which preferably exceeds one second to the rope-pulling force exerted on the hoisting rope is increased in steps or continuously to a value which corresponds to the weight of the load or is sufficient to hoist the load, and that the winch is adapted to be rotated in a payout sense by opposing forces which tend to pull the hoisting rope from the winch and which exceed the instantaneous rope-pulling force.
摘要:
Polyhalogenated cinnamic acids and cinnamic acid derivatives are prepared by reacting diazonium salts accessible from polyhalogenated anilines with acrylic acid or acrylic acid derivatives in the presence of a homogeneous, palladium-containing catalyst at about −5 to about +100° C. Some of the cinnamic acids and cinnamic acid derivatives obtainable in this way are new. Cinnamic acids and cinnamic acid derivatives which can be prepared according to the invention can be used for the preparation of indanones which are precursors for agro- and pharmaceutical chemicals and for substances having liquid-crystalline properties.
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:
Polyhalogenated cinnamic acids and cinnamic acid derivatives are prepared by reacting diazonium salts accessible from polyhalogenated anilines with acrylic acid or acrylic acid derivatives in the presence of a homogeneous, palladium-containing catalyst at about −5 to about +100° C. Some of the cinnamic acids and cinnamic acid derivatives obtainable in this way are new. Cinnamic acids and cinnamic acid derivatives which can be prepared according to the invention can be used for the preparation of indanones which are precursors for agro- and pharmaceutical chemicals and for substances having liquid-crystalline properties.