The present invention provides a method for purifying carbon dioxide gas characterized in that carbon dioxide gas containing at least one of 3-methylmercaptopropionaldehyde and acrolein is contacted with activated carbon to remove at least one of the 3-methylmercaptopropionaldehyde and acrolein. The present invention provides also a method for producing methionine comprising the purification step of the recovered carbon dioxide.

Provided are compounds and salts having a structure of Formula (I) or (II): (I), and (II) wherein: both of the chiral carbon atoms denoted by “*” are both in the R configuration or both in the S configuration. Compounds and salts of Formulae (I) and (II) are useful in the preparation of enantiomerically pure amino acids. Conversion of amino acids to D-form from any of L-form, racemate or other enantiomerically impure mixtures or conversion of amino acids to L-form from any of D-form, racemate or other enantiomerically impure mixtures is disclosed.

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Disclosed are an etelcalcetide intermediate and a method for synthesizing etelcalcetide. The etelcalcetide intermediate is Fmoc-D-Cys(S—S—(N-Boc)-L-Cys(OtBu))-OH. The method for synthesizing the etelcalcetide includes the following steps: using N-Boc-L-Cqs-OtBu as a starting material to generate a primary product of a formula (A) by means of a substitution reaction, herein R is S-Py or Cl; and performing a coupling reaction on the primary product and Fmoc-D-Cys-OH amino acid to obtain Fmoc-D-Cys(S—S—(N-Boc)-L-Cys(OtBu))-OH. The key intermediate is used for synthesizing the etelcalcetide, which may improve the purity and the yield. It is important that the raw materials for synthesizing the key intermediate are cheap and readily available, and the process is simple.

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Disclosed are an etelcalcetide intermediate and a method for synthesizing etelcalcetide. The etelcalcetide intermediate is Fmoc-D-Cys(S—S—(N-Boc)-L-Cys(OtBu))-OH. The method for synthesizing the etelcalcetide includes the following steps: using N-Boc-L-Cqs-OtBu as a starting material to generate a primary product of a formula (A) by means of a substitution reaction, herein R is S-Py or Cl; and performing a coupling reaction on the primary product and Fmoc-D-Cys-OH amino acid to obtain Fmoc-D-Cys(S—S—(N-Boc)-L-Cys(OtBu))-OH. The key intermediate is used for synthesizing the etelcalcetide, which may improve the purity and the yield. It is important that the raw materials for synthesizing the key intermediate are cheap and readily available, and the process is simple.

##STR00001##

This isocyanate production method, for continuously producing an isocyanate while suppressing side reactions, is a method for producing an isocyanate through the thermal decomposition of carbamate, and comprises: a thermal decomposition step in which a mixed solution containing carbamate and a compound (A) having a specific structure is continuously put into a pyrolysis reactor and carry out a pyrolysis reaction of carbamate; a low-boiling-point decomposition product recovery step in which a low-boiling-point decomposition product having a lower standard boiling point than the compound (A) is continuously extracted in a gaseous form from the pyrolysis reactor, and a high-boiling-point component recovery step in which a liquid phase component, which is not recovered in a gaseous form in the low-boiling-point decomposition product recovery step, is continuously extracted as a high-boiling-point component from the pyrolysis reactor.

This isocyanate production method, for continuously producing an isocyanate while suppressing side reactions, is a method for producing an isocyanate through the thermal decomposition of carbamate, and comprises: a thermal decomposition step in which a mixed solution containing carbamate and a compound (A) having a specific structure is continuously put into a pyrolysis reactor and carry out a pyrolysis reaction of carbamate; a low-boiling-point decomposition product recovery step in which a low-boiling-point decomposition product having a lower standard boiling point than the compound (A) is continuously extracted in a gaseous form from the pyrolysis reactor, and a high-boiling-point component recovery step in which a liquid phase component, which is not recovered in a gaseous form in the low-boiling-point decomposition product recovery step, is continuously extracted as a high-boiling-point component from the pyrolysis reactor.

[Problem] Provided is a non-peptide compound which can be used as a GAPDH aggregation inhibitor. [Solution] Provided is a GAPDH aggregation inhibitor including as an active ingredient a compound represented by the chemical formula 1 wherein R.sub.1, R.sub.2, and R.sub.3 are each independently a hydrogen atom, a halogen atom, or an aliphatic hydrocarbon group having a carbon number of from 1 to 10, a polysulfurized derivative thereof, or a pharmaceutically acceptable salt thereof. The present compound has a GAPDH aggregation inhibitory activity to suppress intracerebral aggregation of various proteins involved in cerebral neurodegenerative diseases, thereby contributing to improvement in various brain neurological diseases associated with aggregation of these proteins such as Alzheimer's disease, Parkinson's disease, and cerebral infarction, and prevention of advanced seriousness of these diseases. ##STR00001##

[Problem] Provided is a non-peptide compound which can be used as a GAPDH aggregation inhibitor. [Solution] Provided is a GAPDH aggregation inhibitor including as an active ingredient a compound represented by the chemical formula 1 wherein R.sub.1, R.sub.2, and R.sub.3 are each independently a hydrogen atom, a halogen atom, or an aliphatic hydrocarbon group having a carbon number of from 1 to 10, a polysulfurized derivative thereof, or a pharmaceutically acceptable salt thereof. The present compound has a GAPDH aggregation inhibitory activity to suppress intracerebral aggregation of various proteins involved in cerebral neurodegenerative diseases, thereby contributing to improvement in various brain neurological diseases associated with aggregation of these proteins such as Alzheimer's disease, Parkinson's disease, and cerebral infarction, and prevention of advanced seriousness of these diseases. ##STR00001##

Novel substituted N-acetyl-L-cysteine (NAC) derivatives and related compounds and methods of using these compounds for the treatment of diseases and/or conditions, including but not limited to diseases and/or conditions of, or involving, the Central Nervous System (CNS), including schizophrenia adrenoleukodystrophy, mitochondrial diseases (e.g. Leigh syndrome, Alpers' disease, and MELAS), Huntington's disease, trichotillomania, HIV-associated neurocognitive disorder, hypoxic-ischemic encephalopathy, drug craving, and drug addiction.

Novel substituted N-acetyl-L-cysteine (NAC) derivatives and related compounds and methods of using these compounds for the treatment of diseases and/or conditions, including but not limited to diseases and/or conditions of, or involving, the Central Nervous System (CNS), including schizophrenia adrenoleukodystrophy, mitochondrial diseases (e.g. Leigh syndrome, Alpers' disease, and MELAS), Huntington's disease, trichotillomania, HIV-associated neurocognitive disorder, hypoxic-ischemic encephalopathy, drug craving, and drug addiction.