The present invention relates to novel Ruthenium complexes of formulae A1-A4 and their use, inter alia, for (1) dehydrogenative coupling of alcohols to esters; (2) hydrogenation of esters to alcohols (including hydrogenation of cyclic esters (lactones) or cyclic di-esters (di-lactones), or polyesters); (3) preparing amides from alcohols and amines—(including the preparation of polyamides (e.g., polypeptides) by reacting dialcohols and diamines and/or polymerization of amino alcohols and/or forming cyclic dipeptides from p-aminoalcohols; (4) hydrogenation of amides (including cyclic dipeptides, polypeptides and polyamides) to alcohols and amines; (5) hydrogenation of organic carbonates (including polycarbonates) to alcohols or hydrogenation of carbamates (including polycarbamates) or urea derivatives to alcohols and amines; (6) dehydrogenation of secondary alcohols to ketones; (7) amidation of esters (i.e., synthesis of amides from esters and amines); (8) acylation of alcohols using esters; (9) coupling of alcohols with water and a base to form carboxylic acids; and (10) preparation of amino acids or their salts by coupling of amino alcohols with water and a base. The present, invention further relates to the use of certain known Ruthenium complexes for the preparation of amino acids or their salts from amino alcohols.

The present invention relates to novel Ruthenium complexes of formulae A1-A4 and their use, inter alia, for (1) dehydrogenative coupling of alcohols to esters; (2) hydrogenation of esters to alcohols (including hydrogenation of cyclic esters (lactones) or cyclic di-esters (di-lactones), or polyesters); (3) preparing amides from alcohols and amines—(including the preparation of polyamides (e.g., polypeptides) by reacting dialcohols and diamines and/or polymerization of amino alcohols and/or forming cyclic dipeptides from p-aminoalcohols; (4) hydrogenation of amides (including cyclic dipeptides, polypeptides and polyamides) to alcohols and amines; (5) hydrogenation of organic carbonates (including polycarbonates) to alcohols or hydrogenation of carbamates (including polycarbamates) or urea derivatives to alcohols and amines; (6) dehydrogenation of secondary alcohols to ketones; (7) amidation of esters (i.e., synthesis of amides from esters and amines); (8) acylation of alcohols using esters; (9) coupling of alcohols with water and a base to form carboxylic acids; and (10) preparation of amino acids or their salts by coupling of amino alcohols with water and a base. The present, invention further relates to the use of certain known Ruthenium complexes for the preparation of amino acids or their salts from amino alcohols.

The present invention provides a system and method of storing hydrogen (H.sub.2) and releasing it on demand, comprising and making use of diaminoalkanes and alcohols, or aminoalcohols as liquid-organic hydrogen carrier systems (LOHC). 2-amino-ethanol (AE) or its N-methyl derivative 2-(methylamino)ethanol undergo catalytic dehydrogenation to form a cyclic dipeptide (glycine anhydride—GA) or its N,N-dimethyl derivative (N,N-dimethyl GA) with release of hydrogen. Similarly, ethylenediamine (ED) and ethanol undergo catalytic dehydrogenation to form N,N′-diacetylethylenediamine (DAE) with release of hydrogen. Glycine anhydride (GA) or N,N-dimethyl-GA may be hydrogenated back to 2-aminoethanol (AE) or 2-(methylamino)ethanol, respectively, each of which functions as a hydrogen storage system. N,N′-diacetylethylenediamine (DAE) may be hydrogenated back to ED and ethanol, which functions as a hydrogen storage system. These reactions may be catalyzed by a variety of compounds or complexes, including Ruthenium complexes as described herein.

The present invention provides a system and method of storing hydrogen (H.sub.2) and releasing it on demand, comprising and making use of diaminoalkanes and alcohols, or aminoalcohols as liquid-organic hydrogen carrier systems (LOHC). 2-amino-ethanol (AE) or its N-methyl derivative 2-(methylamino)ethanol undergo catalytic dehydrogenation to form a cyclic dipeptide (glycine anhydride—GA) or its N,N-dimethyl derivative (N,N-dimethyl GA) with release of hydrogen. Similarly, ethylenediamine (ED) and ethanol undergo catalytic dehydrogenation to form N,N′-diacetylethylenediamine (DAE) with release of hydrogen. Glycine anhydride (GA) or N,N-dimethyl-GA may be hydrogenated back to 2-aminoethanol (AE) or 2-(methylamino)ethanol, respectively, each of which functions as a hydrogen storage system. N,N′-diacetylethylenediamine (DAE) may be hydrogenated back to ED and ethanol, which functions as a hydrogen storage system. These reactions may be catalyzed by a variety of compounds or complexes, including Ruthenium complexes as described herein.

A method for preparing chiral γ-secondary amino alcohol includes: adding into a solvent an acid addition salt of β-secondary amino ketone represented by general formula (1), an alkali, a metal salt additive and a diphosphine-rhodium complex, so as to carry out a reaction in a hydrogen atmosphere and obtain a chiral γ-secondary amino alcohol compound represented by general formula (2). In general formula (2), Ar represents an aryl group with or without substituent group(s), R represents an alkyl group or an aralkyl group, and HY represents an acid. The synthesis scheme has a simple process, the metal salt additive remarkably improves the effect of a rhodium-catalyzed asymmetric hydrogenation technology, and accordingly, the reaction yield and the optical purity of a product are improved, the production process is simplified, production costs are reduced, and the synthesis scheme is highly suitable for mass industrial production.

##STR00001##

A method for preparing chiral γ-secondary amino alcohol includes: adding into a solvent an acid addition salt of β-secondary amino ketone represented by general formula (1), an alkali, a metal salt additive and a diphosphine-rhodium complex, so as to carry out a reaction in a hydrogen atmosphere and obtain a chiral γ-secondary amino alcohol compound represented by general formula (2). In general formula (2), Ar represents an aryl group with or without substituent group(s), R represents an alkyl group or an aralkyl group, and HY represents an acid. The synthesis scheme has a simple process, the metal salt additive remarkably improves the effect of a rhodium-catalyzed asymmetric hydrogenation technology, and accordingly, the reaction yield and the optical purity of a product are improved, the production process is simplified, production costs are reduced, and the synthesis scheme is highly suitable for mass industrial production.

##STR00001##

A method for preparing chiral γ-secondary amino alcohol includes: adding into a solvent an acid addition salt of β-secondary amino ketone represented by general formula (1), an alkali, a metal salt additive and a diphosphine-rhodium complex, so as to carry out a reaction in a hydrogen atmosphere and obtain a chiral γ-secondary amino alcohol compound represented by general formula (2). In general formula (2), Ar represents an aryl group with or without substituent group(s), R represents an alkyl group or an aralkyl group, and HY represents an acid. The synthesis scheme has a simple process, the metal salt additive remarkably improves the effect of a rhodium-catalyzed asymmetric hydrogenation technology, and accordingly, the reaction yield and the optical purity of a product are improved, the production process is simplified, production costs are reduced, and the synthesis scheme is highly suitable for mass industrial production.

##STR00001##

There is provided a process for the reduction of one or more amide moieties in a compound comprising contacting the compound with hydrogen gas and a transition metal catalyst in the presence or absence of a base under conditions for the reduction an amide bond. The presently described processes can be performed at low catalyst loading using relatively mild temperature and pressures, and optionally, in the presence or absence of a base or high catalyst loadings using low temperatures and pressures and high loadings of base to effect dynamic kinetic resolution of achiral amides.

There is provided a process for the reduction of one or more amide moieties in a compound comprising contacting the compound with hydrogen gas and a transition metal catalyst in the presence or absence of a base under conditions for the reduction an amide bond. The presently described processes can be performed at low catalyst loading using relatively mild temperature and pressures, and optionally, in the presence or absence of a base or high catalyst loadings using low temperatures and pressures and high loadings of base to effect dynamic kinetic resolution of achiral amides.

There is provided a process for the reduction of one or more amide moieties in a compound comprising contacting the compound with hydrogen gas and a transition metal catalyst in the presence or absence of a base under conditions for the reduction an amide bond. The presently described processes can be performed at low catalyst loading using relatively mild temperature and pressures, and optionally, in the presence or absence of a base or high catalyst loadings using low temperatures and pressures and high loadings of base to effect dynamic kinetic resolution of achiral amides.