The present invention relates to a process for the preparation of methionine comprising the step of contacting a solution or suspension comprising 2-amino-4-(methylthio)butanenitrile and/or 2-amino-4-(methylthio)butaneamide with water in the presence of a catalyst to give a methionine comprising mixture, wherein the catalyst comprises CeO.sub.2 comprising particles, wherein the CeO.sub.2 comprising particles comprise from 50 to 100 wt.-% of CeO.sub.2, have a BET surface area of from 35 to 65 m.sup.2/g measured according to DIN ISO 9277-5 (2003), a mean maximum Feret diameter x.sub.Fmax, mean of from 10 to 40 nm and a mean minimum Feret diameter x.sub.Fmin, mean of from 5 to 30 nm, both measured according to DIN ISO 9276-6 (2012).

The present invention relates to a process for the preparation of methionine comprising the step of contacting a solution or suspension comprising 2-amino-4-(methylthio)butanenitrile and/or 2-amino-4-(methylthio)butaneamide with water in the presence of a catalyst to give a methionine comprising mixture, wherein the catalyst comprises CeO.sub.2 comprising particles, wherein the CeO.sub.2 comprising particles comprise from 50 to 100 wt.-% of CeO.sub.2, have a BET surface area of from 35 to 65 m.sup.2/g measured according to DIN ISO 9277-5 (2003), a mean maximum Feret diameter x.sub.Fmax, mean of from 10 to 40 nm and a mean minimum Feret diameter x.sub.Fmin, mean of from 5 to 30 nm, both measured according to DIN ISO 9276-6 (2012).

The present specification discloses a method of producing a concentrated carbonate aqueous solution. The present invention relates to a method for producing a concentrated carbonate aqueous solution, comprising a step of dewatering a hydrogen carbonate aqueous solution by means of a salt blocking membrane to prepare a concentrated hydrogen carbonate aqueous solution, wherein the concentrated hydrogen carbonate aqueous solution obtained in the above step is heated to thermally decompose the hydrogen carbonate into carbonate, carbon dioxide and water, and to evaporate water to obtain a concentrate of the carbonate aqueous solution.

The present specification discloses a method of producing a concentrated carbonate aqueous solution. The present invention relates to a method for producing a concentrated carbonate aqueous solution, comprising a step of dewatering a hydrogen carbonate aqueous solution by means of a salt blocking membrane to prepare a concentrated hydrogen carbonate aqueous solution, wherein the concentrated hydrogen carbonate aqueous solution obtained in the above step is heated to thermally decompose the hydrogen carbonate into carbonate, carbon dioxide and water, and to evaporate water to obtain a concentrate of the carbonate aqueous solution.

The present invention provides a method for producing a monosulfoxide derivative.

The present invention provides a method for producing a monosulfoxide derivative.

The present invention provides a method for producing a monosulfoxide derivative.

[Problem] To provide a labeled fatty acid derivative for diagnostic imaging that enables the quantification of myocardial fatty acid metabolic activity. [Solution] The inventors, engaging in diligent research into methods that enable the quantification of fatty acid metabolic activity, discovered that a labeled fatty acid derivative represented by formula (1), in which [.sup.18F] has been substituted at a specific position of a long-chain carboxylic acid compound containing a sulfur atom, or a salt thereof, has good accumulation in the myocardium, and enables imaging of fatty acid metabolic activity via positron emission tomography (PET). Therefore, the labeled fatty acid derivative according to the present invention can be used as a radiotracer for swift and noninvasive quantification of myocardial fatty acid metabolic activity, diagnostic imaging of heart diseases such as ischemic heart disease, diagnostic imaging of the therapeutic effects yielded by a heart disease therapeutic agent, and so forth.

[Problem] To provide a labeled fatty acid derivative for diagnostic imaging that enables the quantification of myocardial fatty acid metabolic activity. [Solution] The inventors, engaging in diligent research into methods that enable the quantification of fatty acid metabolic activity, discovered that a labeled fatty acid derivative represented by formula (1), in which [.sup.18F] has been substituted at a specific position of a long-chain carboxylic acid compound containing a sulfur atom, or a salt thereof, has good accumulation in the myocardium, and enables imaging of fatty acid metabolic activity via positron emission tomography (PET). Therefore, the labeled fatty acid derivative according to the present invention can be used as a radiotracer for swift and noninvasive quantification of myocardial fatty acid metabolic activity, diagnostic imaging of heart diseases such as ischemic heart disease, diagnostic imaging of the therapeutic effects yielded by a heart disease therapeutic agent, and so forth.

Presented herein are methods for making, isolating, and purifying N-acetylcysteine amide, (2R,2R′)-3,3′-disulfanediyl bis(2-acetamidopropanamide, diNACA), intermediates and derivatives thereof comprising: alternatively contacting cystine with methanol and a chlorinating reagent to form an organic solution containing L-cystine dimethylester dihydrochloride; combining dried or undried L-cystine dimethylester dihydrochloride with a triethylamine, an acetic anhydride, and an acetonitrile to form a di-N-acetylcystine dimethylester; mixing dried di-N-acetylcystine dimethylester with ammonium hydroxide to form a di-N-acetylcystine amide (diNACA); and separating dried di-N-acetylcystine dimethylester into N-acetylcysteine amide with dithiothreitol, triethylamine, and an alcohol.