A process for the preparation of five-membered or six-membered ring lactams from aliphatic α,ω-dinitriles has been developed. In the process an aliphatic α,ω-dinitrile is first converted to an ammonium salt of an ω-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 ω-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate ω-nitrilecarboxylic acid or ω-aminocarboxylic acid. When the aliphatic α,ω-dinitrile is also unsymmetrically substituted at the α-carbon atom, the nitrilase produces the ω-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the ω-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.
我们开发了一种从脂肪族 α,ω-二腈制备五元环或六元环内酰胺的工艺。在该工艺中,首先在
水溶液中使用具有脂肪族硝化酶(
EC 3.5.5.7)活性或兼具腈
水解酶(
EC 4.2.1.84)和酰胺酶(
EC 3.5.1.4)活性的催化剂将脂肪族 α,ω-二腈转化为ω-腈
羧酸的
铵盐。然后,ω-腈
羧酸的
铵盐在
水溶液中通过氢化作用直接转化为相应的内酰胺,而无需分离中间体ω-腈
羧酸或ω-
氨基
羧酸。当脂肪族α,ω-二腈在α-碳原子上也被非对称取代时,硝化酶
水解ω-腈基产生的ω-腈
羧酸铵盐的区域选择性大于 98%,从而在随后的氢化过程中只产生两种可能内酰胺产物中的一种。此外,还提供了一种热处理工艺,用于选择理想的区域选择性硝化酶或腈
水解酶活性,同时破坏不理想的活性。