摘要:
The present invention provides a useful novel intermediate and a novel synthetic process that can highly prevent contamination by various impurities to an optically active R or S isomer of a 2-amino-3-mercapto-2-methylpropionic acid derivative or salt thereof useful as an intermediate for pharmaceuticals and the like and provides a process for easily and efficiently producing a high purity optically active R or S isomer of a 2-amino-3-mercapto-2-methylpropionic acid derivative or salt thereof on an industrial production scale. A process of producing a high purity 2-amino-3-mercapto-2-methylpropionic acid derivative or salt thereof includes reductively cleaving a sulfur-sulfur bond of an intermediate, which is a high purity optically active 3,3′-dithiobis(2-amino-2-methylpropionic acid) derivative substantially free of impurities. Thus, a resulting optically active 2-amino-3-mercapto-2-methylpropionic acid derivative can be produced without generating impurities as by-products which are difficult to remove.
摘要:
This invention provides a method of isolating N-protected-S-phenylcysteine (1) of high purity, expediently, efficiently and in good yield, which comprises causing said N-protected-S-phenylcysteine to be salted out in the form of a base salt in the presence of water. wherein R1 represents an amino-protecting group; R2 represents a hydrogen atom or, either independently of R1 or taken together with R1, represents an amino-protecting group.
摘要翻译:本发明提供了一种方法,有效和高效分离高纯度N-保护的S-苯基半胱氨酸(1)的方法,其包括使所述N-保护的S-苯基半胱氨酸以碱的形式盐析 盐,其中R 1表示氨基保护基; R 2表示氢原子,或独立地为R 1或与R 1一起表示氨基保护基。
摘要:
The present invention provides a process of starting from N-alkoxycarbonyl-ethylamine compounds having a leaving group at the β-position to prepare oxazolidinone derivatives of β-hydroxyethylamine compounds having an inverted steric configuration at the β-position carbon, which comprises introducing a step of treating in contact with water with heating under acidic to neutral conditions into the process. Also, the present invention provides a process of starting from N-alkoxycarbonyl-ethylamine compounds having a leaving group at the β-position to prepare β-hydroxyethylamine compounds having an inverted steric configuration at the β-position carbon, which comprises subjecting the oxazolidinone derivatives prepared as described above to a step of treating in contact with water under basic conditions.
摘要:
This invention relates to a method comprising reacting an amino acid derivative of the following general formula (I); ##STR1## (wherein R.sup.1 represents an amino-protective group; R.sup.0 represents hydrogen or, taken together with R.sup.1, represents an amino-protecting group; R.sup.2 represents a carboxy-protecting group; X represents a leaving group) with a thiol compound of the following general formula (II):R.sup.3 SH (II)(wherein R.sup.3 represents an alkyl group of 1 to 7 carbon atoms, an aryl group of 6 to 10 carbon atoms, or an aralkyl group of 7 to 10 carbon atoms) to give a cysteine derivative of the following general formula (III): ##STR2## (wherein R.sup.0, R.sup.1, R.sup.2, and R.sup.3 are as defined above), wherein the reaction is conducted in the presence of a base and water in an organic reaction solvent.
摘要:
The present invention provides a process for preparing 3-amino-2-hydroxypropionic acid derivatives (1) which does not use dangerous reagents, is economically advantageous, and is suitable for an industrial production, which process comprises: treating N-protected-3-amino-2-hydroxypropionic acid derivatives (2) having a steric configuration at 2-position carbon reverse to that of derivatives (1) with a leaving group-introducing agent to convert into N-protected-3-aminopropionic acid derivatives (3), then treating the derivatives with a basic substance to convert into substituted-3-amino-2-hydroxypropionic acid derivatives (4) having an inverted steric configuration at 2-position carbon, and then converting the derivatives into 3-amino-2-hydroxypropionic acid derivatives (1).
摘要:
A process for producing optically active cysteine derivatives with high optical purity and good quality which is economically advantageous and is high in productivity even on a commercial scale is provided. A process for producing an optically active cysteine derivative which comprises synthesizing a D-form or L-form optically active cysteine derivative of the general formula (2) shown below (R1 represents an amino-protecting group of the urethane or acyl type, R0 represents a hydrogen atom or, taken together with R1, an amino-protecting group, R2 represents an alkyl, aryl or aralkyl group, R3 represents a univalent organic group and * represents the position of an asymmetric carbon) by reacting the corresponding D-form or L-form optically active amino acid derivative of the general formula (1) shown below with an alcohol of the general formula (3) shown below and a strong acid and/or a thionyl halide and recovering the above cysteine derivative (2) from the reaction mixture, the procedural series from reaction to recovery being carried out under conditions such that the medium contacting the above optically active cysteine derivative (2) is within the range from acidic to weakly basic to thereby recover the above cysteine derivative (2) from the reaction mixture while suppressing the decomposition and racemization thereof.
摘要:
The present invention has for its object to provide a commercially useful, expedient and efficient method for purification and isolation of an N-protected (2S,3R)-1-halo-2-hydroxy-3-amino-4-phenylthiobutane (1) or its enantiomer, which is capable of removing the various contaminants, particularly said byproducts, whereby the problem of instability of the compound (1) or its enantiomer can be overcome and a high product yield can be insured.The present invention relates to a method of purifying and isolating an N-protected (2S,3R)-1-halo-2-hydroxy-3-amino-4-phenylthiobutane (1): ##STR1## (wherein X represents a halogen atom; one of P.sup.1 and P.sup.2 represents a hydrogen atom and the other represents an amino-protecting group, or P.sup.1 and P.sup.2 taken together represents an amino-protecting group) or its enantiomer, which comprises using an aromatic hydrocarbon solvent to remove impurities occurring in said compound (1) or impurities occurring in said enantiomer from said compound (1) containing impurities or its enantiomer containing impurities and isolate said compound (1) or said enantiomer as crystals.
摘要:
An industrially advantageous method of producing &bgr;-halogeno-&agr;-aminocarboxylic acids is provided. Methods are also provided of producing optically active N-protected-S-phenylcysteines having high optical purity and of intermediates thereof, respectively, in which the above production method is utilized. A method of producing &bgr;-halogeno-&agr;-aminocarboxylic acids or salts thereof is disclosed which comprises halogenating the hydroxyl group of a &bgr;-hydroxy-&agr;-aminocarboxylic acid (in which the basicity of the amino group in &agr;-position is not masked by the presence of a substituent on said amino group) or a salt thereof with an acid with a halogenating agent. A method of producing optically active N-protected-S-phenylcysteines represented by the general formula (3) or salts thereof is further disclosed which comprises applying the above production method to optically active serine or a salt thereof and then carrying out treatment with an amino-protecting agent and reaction with thiophenol under a basic condition.
摘要:
The present invention provides a production method of high quality threo-1,2-epoxy-3-amino-4-phenylbutane derivatives (1) on a commercial scale in a simple, easy and efficient manner and with very high productivity, which comprises treating a threo-1-halo-2-hydroxy-3-amino-4-phenylbutane derivative (2) with a base in a polar organic solvent or a solvent composed of a polar organic solvent and water, and adding the resulting reaction mixture to water to thereby cause the resulting threo-1,2-epoxy-3-amino-4-phenylbutane derivative (1) to crystallize out.
摘要:
A magnetic media processing device including an encoder for producing an output for a predetermined distance in a conveyance distance of a magnetic media on conveyance, a road circuit device for reading magnetic data stored in the magnetic media in synchronizing the output from the encoder to be processed as to its waveforms to produce read data, and an arithmetic device for converting a data length to data of a distance based on a time component of a data length of the read data of the read circuit device by employing the output signal from the encoder to read data based on distance data, wherein the arithmetic device compensates the process delay time in a time component of read data produced from the read circuit device when the arithmetic device converts the data length into the data of distance.