Abstract:
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha.,.omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrilecarboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and amidase (EC 3.5.1.4) activities. The ammonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-aminocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying undesirable activities is also provided.
Abstract:
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha.,.omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrile-carboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and arnidase (EC 3.5.1.4) activities. The ammonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-aminocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying undesirable activities is also provided.
Abstract:
A process for the preparation of 3- and/or 6-substituted 2,5-morpholinediones is disclosed. Such morpholinediones are useful as precursors for the preparation of depsipeptide polymers and copolymers.
Abstract:
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha.,.omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrilecarboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and amidase (EC 3.5.1.4) activities. The ammonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-aminocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying undesirable activities is also provided.
Abstract:
This invention relates to a process for preparing 1,4-dioxane-2,5-diones comprising reacting an .alpha.-hydroxy acid oligomer or an ester of an .alpha.-hydroxy acid oligomer over a fixed bed catalyst system.
Abstract:
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha.,.omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrilecarboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and amidase (EC 3.5.1.4) activities. The ammonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-aminocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying undesirable activities is also provided.
Abstract:
Enzymes which are capable of catalyzing esterifications and/or transesterifications such as selected lipases and esterases can, under specified conditions, convert certain lower linear oligomers of polyesters to their cyclic ester oligomers in quantities greater than would be predicted by thermodynamic calculation or prior art methods. The cyclic ester oligomers are useful for the production of higher molecular weight linear polyesters.
Abstract:
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha., .omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrilecarboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and amidase (EC 3.5.1.4) activities. The ammonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-aminocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying undesirable activities is also provided.
Abstract:
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha.,.omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrilecarboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and amidase (EC 3.5.1.4) activities. The aimnonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-monocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying undesirable activities is also provided.
Abstract:
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha.,.omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrile-carboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and amidase (EC 3.5.1.4) activities. The ammonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-aminocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying undesirable activities is also provided.