The invention relates to the field of resolution of chiral compounds existing in the form of two optical antipodes (enantiomers), such as Baclofen. More particularly, the invention relates to the production of the pure enantiomer (R)() Baclofen, of chemical nomenclature (R)-4-amino-3-(4-chlorophenyl)-butanoic acid, and the hydrogen maleate salt thereof. More specifically, the invention relates to the resolution of hydrogen maleate salts of racemic Baclofen by preferential crystallisation and particularly by the AS3PC method (auto-seeded and programmed polythermal preferential crystallisation).

The invention relates to the field of resolution of chiral compounds existing in the form of two optical antipodes (enantiomers), such as Baclofen. More particularly, the invention relates to the production of the pure enantiomer (R)() Baclofen, of chemical nomenclature (R)-4-amino-3-(4-chlorophenyl)-butanoic acid, and the hydrogen maleate salt thereof. More specifically, the invention relates to the resolution of hydrogen maleate salts of racemic Baclofen by preferential crystallisation and particularly by the AS3PC method (auto-seeded and programmed polythermal preferential crystallisation).

The invention relates to the field of resolution of chiral compounds existing in the form of two optical antipodes (enantiomers), such as Baclofen. More particularly, the invention relates to the production of the pure enantiomer (R)() Baclofen, of chemical nomenclature (R)-4-amino-3-(4-chlorophenyl)-butanoic acid, and the hydrogen maleate salt thereof. More specifically, the invention relates to the resolution of hydrogen maleate salts of racemic Baclofen by preferential crystallisation and particularly by the AS3PC method (auto-seeded and programmed polythermal preferential crystallisation).

Disclosed is a method for synthesizing a novel chiral ligand, a metal chelate, a variety of non-natural amino acids, Maraviroc and a key intermediate thereof. In the invention, (R)-2-methyl proline is selected and used as a starting raw material, (S)-.sup.3-amino acid is obtained by asymmetric resolution induced by using a nickel chelate, and Maraviroc is synthesized by using (S)-3-amino-3-phenylpropionic acid as a key intermediate with a high yield and the ee value reaching 98.2% or more. The method of the present invention has widely available materials, mild synthetic process conditions, is easy to control, and produces a product of a high optical purity.

Disclosed is a method for synthesizing a novel chiral ligand, a metal chelate, a variety of non-natural amino acids, Maraviroc and a key intermediate thereof. In the invention, (R)-2-methyl proline is selected and used as a starting raw material, (S)-.sup.3-amino acid is obtained by asymmetric resolution induced by using a nickel chelate, and Maraviroc is synthesized by using (S)-3-amino-3-phenylpropionic acid as a key intermediate with a high yield and the ee value reaching 98.2% or more. The method of the present invention has widely available materials, mild synthetic process conditions, is easy to control, and produces a product of a high optical purity.

The present invention is related to a product for the resolution of racemic mixtures in which various separation processes of a salt composed of a PEGylated resolving agent and an enantiomer in a racemic mixture is utilized. Separation can be caused by temperature-dependent phase transformation of the said salt pair in aqueous or organic media as well as other methods used is separation of PEG such as salting out (e.g. addition of ammonium sulfate). The first cycle of racemic resolution by this method was shown to afford 85% optically pure amino acid from a 50:50 mixture of racemic L,D-amino acids esters. An additional cycle improved optical purity up to 95%.

The present invention is related to a product for the resolution of racemic mixtures in which various separation processes of a salt composed of a PEGylated resolving agent and an enantiomer in a racemic mixture is utilized. Separation can be caused by temperature-dependent phase transformation of the said salt pair in aqueous or organic media as well as other methods used is separation of PEG such as salting out (e.g. addition of ammonium sulfate). The first cycle of racemic resolution by this method was shown to afford 85% optically pure amino acid from a 50:50 mixture of racemic L,D-amino acids esters. An additional cycle improved optical purity up to 95%.

The present invention is related to a product for the resolution of racemic mixtures in which various separation processes of a salt composed of a PEGylated resolving agent and an enantiomer in a racemic mixture is utilized. Separation can be caused by temperature-dependent phase transformation of the said salt pair in aqueous or organic media as well as other methods used is separation of PEG such as salting out (e.g. addition of ammonium sulfate). The first cycle of racemic resolution by this method was shown to afford 85% optically pure amino acid from a 50:50 mixture of racemic L,D-amino acids esters. An additional cycle improved optical purity up to 95%.

A method of preparing D-4,4-biphenylalanine alkyl ester or L-4,4-biphenylalanine alkyl ester by subjecting DL-4,4-biphenylalanine alkyl ester to optical resolution using chiral diaroyl tartaric acid as an optical resolving agent is provided.

A method of preparing D-4,4-biphenylalanine alkyl ester or L-4,4-biphenylalanine alkyl ester by subjecting DL-4,4-biphenylalanine alkyl ester to optical resolution using chiral diaroyl tartaric acid as an optical resolving agent is provided.