The present invention aims to provide a method of producing, more efficiently at a high purity, a phosphoramidite preferable for the production (synthesis) of a nucleic acid. Using a coupling reaction of an ether represented by the following chemical formula (105), an enantiomer, tautomer or stereoisomer thereof, or a salt thereof, and a glycoside compound, phosphoramidite that enables efficient synthesis of nucleic acid can be obtained:

##STR00001##

wherein n is a positive integer, and R and R′ are the same or different and each is a hydrogen atom or a hydroxyl-protecting group.

The present invention aims to provide a method of producing, more efficiently at a high purity, a phosphoramidite preferable for the production (synthesis) of a nucleic acid. Using a coupling reaction of an ether represented by the following chemical formula (105), an enantiomer, tautomer or stereoisomer thereof, or a salt thereof, and a glycoside compound, phosphoramidite that enables efficient synthesis of nucleic acid can be obtained:

##STR00001##

wherein n is a positive integer, and R and R′ are the same or different and each is a hydrogen atom or a hydroxyl-protecting group.

The present invention aims to provide a method of producing, more efficiently at a high purity, a phosphoramidite preferable for the production (synthesis) of a nucleic acid. Using a coupling reaction of an ether represented by the following chemical formula (105), an enantiomer, tautomer or stereoisomer thereof, or a salt thereof, and a glycoside compound, phosphoramidite that enables efficient synthesis of nucleic acid can be obtained:

##STR00001##

wherein n is a positive integer, and R and R′ are the same or different and each is a hydrogen atom or a hydroxyl-protecting group.

An effective process of making N,N′-diacetyl-L-Cystine (“NDAC”), which process is fast, green, does not require labor-intensive isolation or purification of the product, by yielding products in desired ratio, and has improved yield and purity. The process comprising the steps of Forming a reaction mixture, starting with a cystine derivative di-tert- butyl-L-cystine as the dihydrochloride form; Acetylating said di-tert-butyl-L-cystine to obtain N,N′-diacetyl-di-tert- butyl-L-cystine; followed by Removing said tert- butyl groups from said N,N′-diacetyl-di-tert-butyl- L-cystine to obtain N,N′-diacetyl-L-cystine product; and Isolating said N,N′-diacetyl-L-Cystine product from said reaction mixture; wherein said acetylating agent is acetic anhydride.

An effective process of making N,N′-diacetyl-L-Cystine (“NDAC”), which process is fast, green, does not require labor-intensive isolation or purification of the product, by yielding products in desired ratio, and has improved yield and purity. The process comprising the steps of Forming a reaction mixture, starting with a cystine derivative di-tert- butyl-L-cystine as the dihydrochloride form; Acetylating said di-tert-butyl-L-cystine to obtain N,N′-diacetyl-di-tert- butyl-L-cystine; followed by Removing said tert- butyl groups from said N,N′-diacetyl-di-tert-butyl- L-cystine to obtain N,N′-diacetyl-L-cystine product; and Isolating said N,N′-diacetyl-L-Cystine product from said reaction mixture; wherein said acetylating agent is acetic anhydride.

The present invention provides a method for preparing an intermediate of florfenicol, comprising: reacting p-methylthiobenzaldehyde with isocyanoacetate under catalysis of a chiral catalyst. In the reaction, the chiral product is oxidized to form a methylsulfone-substituted product which is subsequently deformylized to obtain the intermediate. In the method of the present invention, the chiral center of the intermediate is directly generated in the first step of reaction, and the yield of the first step reaches 75%-80%, which is significantly higher than the conventional chiral resolution methods (about 40% yield), and the product has high chiral purity. The method of the present invention does not use anhydrous copper sulfate that pollutes the environment, which reduces the environmental pressure. The compound of p-methylthiobenzaldehyde and the compound of isocyanoacetate are used to react to form a chiral intermediate, which has higher material availability and efficiency than linear synthesis methods.

The present invention provides a method for preparing an intermediate of florfenicol, comprising: reacting p-methylthiobenzaldehyde with isocyanoacetate under catalysis of a chiral catalyst. In the reaction, the chiral product is oxidized to form a methylsulfone-substituted product which is subsequently deformylized to obtain the intermediate. In the method of the present invention, the chiral center of the intermediate is directly generated in the first step of reaction, and the yield of the first step reaches 75%-80%, which is significantly higher than the conventional chiral resolution methods (about 40% yield), and the product has high chiral purity. The method of the present invention does not use anhydrous copper sulfate that pollutes the environment, which reduces the environmental pressure. The compound of p-methylthiobenzaldehyde and the compound of isocyanoacetate are used to react to form a chiral intermediate, which has higher material availability and efficiency than linear synthesis methods.

In one embodiment, the present application discloses a catalyst composition comprising: a) a reaction solvent or a reaction medium; b) organometallic nanoparticles comprising: i) a nanoparticle (NP) catalyst, prepared by a reduction of an iron salt in an organic solvent, wherein the catalyst comprises at least one other metal selected from the group consisting of Pd, Pt, Au, Ni, Co, Cu, Mn, Rh, Ir, Ru and Os or mixtures thereof; c) a ligand; and d) a surfactant; wherein the metal or mixtures thereof is present in less than or equal to 50,000 ppm relative to the iron salt.

In one embodiment, the present application discloses a catalyst composition comprising: a) a reaction solvent or a reaction medium; b) organometallic nanoparticles comprising: i) a nanoparticle (NP) catalyst, prepared by a reduction of an iron salt in an organic solvent, wherein the catalyst comprises at least one other metal selected from the group consisting of Pd, Pt, Au, Ni, Co, Cu, Mn, Rh, Ir, Ru and Os or mixtures thereof; c) a ligand; and d) a surfactant; wherein the metal or mixtures thereof is present in less than or equal to 50,000 ppm relative to the iron salt.

In one embodiment, the present application discloses a catalyst composition comprising: a) a reaction solvent or a reaction medium; b) organometallic nanoparticles comprising: i) a nanoparticle (NP) catalyst, prepared by a reduction of an iron salt in an organic solvent, wherein the catalyst comprises at least one other metal selected from the group consisting of Pd, Pt, Au, Ni, Co, Cu, Mn, Rh, Ir, Ru and Os or mixtures thereof; c) a ligand; and d) a surfactant; wherein the metal or mixtures thereof is present in less than or equal to 50,000 ppm relative to the iron salt.