摘要:
There are produced 2-isocyanato-2,3-dehydrocarboxylic acid esters of the general formula: ##STR1## in which R.sup.1 is a straight chain or branched C.sub.1 -C.sub.4 -alkyl group, a phenyl group or a benzyl group, R.sup.2 is hydrogen or a methyl group and R.sup.3 is hydrogen, a straight chain or branched C.sub.1 -C.sub.16 -alkyl group, a C.sub.3 -C.sub.8 -cycloalkyl group, a C.sub.1 -C.sub.6 -alkylmercapto group or a phenyl group by reacting a 2-azido-carboxylic acid ester of the general formula: ##STR2## in an inert solvent at a temperature between 0.degree. and 150.degree. C. with phosgene or diphosgene in the presence of a perrhenate. The compounds of general formula (I) can be converted into the corresponding Z- or BOC-protected 2,3-dehydro-2-amino-carboxylic acid ester with benzyl alcohol or with tert. butyl alcohol, which esters in turn are valuable building blocks for the synthesis of dehydropeptides.
摘要:
Aminoacid hydrochlorides or diaminoacid dihydrochlorides are produced by first reacting a halocarboxylic acid ester with an alkali metal cyanate in the presence of an alcohol to form the corresponding mono- or diurethane and then saponifying this to the corresponding mono- or dihydrochloride. The new process is relatively versatile in its use and above all opens up an elegant synthesis route for lysine.
摘要:
L-proline is produced from the methyl or ethyl ester of L-pyroglutamic acid by reacting this with at least twice the molar amount of phosgene to form the corresponding 1-chlorocarbonyl-5,5-dichloroproline ester, producing the corresponding 2-chloro-1-chlorocarbonyl-pyrrolin-(2)-carboxylic acid ester-(5) therefrom by splitting off hydrogen chloride, catalytically hydrogenating the pyrrolin-(2) compound to the corresponding N-chlorocarbonyl-proline ester and hydrolyzing the latter with acid to form L-proline.
摘要:
The present invention relates to a screening process for hydantoin racemases and to novel hydantoin racemases, to the nucleic acid sequences coding therefor and to a proces for mutagenesis. Hydantoin racemases are of interest in connection with the production of enantiomerically enriched amino acids from racemic hydantoins.
摘要:
A novel route is described for the synthesis of N-methyl-3-hydroxy-3-(2-thienyl)propylamine IV, which can be used as a starting compound for the preparation of duloxetine. N-methyl-3-hydroxy-3-(2-thienyl)propylamine is synthesized via novel thiophene derivatives containing carbamate groups, I and IIa, as intermediates.
摘要:
A process is described for preparing optically active β-atninocarboxylic acids from racemic N-acylated β-aminocarboxylic acids by cnantiosclccthc hydrolysis of the N-acylated β-aminocarboxylic acid in the presence of a hydrolase by way of biocatalyst, wherein the N-acyl substituent of the N-acylated β-aminocarboxylic acid (I) exhibits Structure I in which R1, R2 are each selected, independently of one another, from H, halogen, alkiyl residues, OH, alkoxy residues and aryloxy residues; R3 is selected from halogen, alkoxy residues and aryloxy residues; (II) Structure IIA or IIB or the structure of the corresponding salts or (III) Structure III or the structure of the corresponding salt.
摘要翻译:描述了一种用于通过在水解酶存在下通过生物催化剂的N-酰化β-氨基羧酸水解N-外酰基化的β-氨基羧酸来制备光学活性β-阿魏酸的方法,其中N-酰基取代基 的N-酰化的β-氨基羧酸(I)表现出结构I,其中R 1,R 2各自彼此独立地选自H,卤素, 烷基残基,OH,烷氧基残基和芳氧基残基; R 3选自卤素,烷氧基残基和芳氧基残基; (II)结构IIA或IIB或相应盐的结构或(III)结构III或相应盐的结构。
摘要:
A molecular weight-enlarged, homogeneously soluble ligand, useful in catalysts, particularly for the synthesis of enantiomerically enriched organic compounds, includes: a weight average molecular weight of at least 1000 g/mol; a molecular weight-enlarging polymer; optionally, a polymer linker; and at least one homochiral active center; wherein the active center is bound to the molecular weight-enlarging polymer through the polymer linker or is bound directly to the molecular weight-enlarging polymer.
摘要:
Many inorganic substrates can be oxidized with a peroxo compound, such as hydrogen peroxide. In processes which are already known, pure alkylrhenium oxides of the formula RaRebOcLd are employed. Catalyst compositions such as are obtainable from the reaction of an oxorhenium compound of the formula ReOmAn with an organylating agent, in particular a Grignard compound, without the preparation process comprising an expensive sublimation, crystallization or distillation, can be employed with the same activity in the oxidation reactions. In addition to oxidation processes, catalyst compositions are disclosed.
摘要:
The present invention relates to the preparation of compounds of formula (I): from the corresponding hydantoins by means of an enzymatic process. The L-compound is preferably formed.
摘要:
Molecular weight-enlarged, homogeneously soluble ligands are provided that are especially useful for hydrogenation catalysts, wherein the ligands contain homochiral active centers of bis(3,4-diarylphosphinyl)pyrrolidines, and their use in producing cataylsts for enantioselective reactions, as well as the catalysts thus produced.