Method for preparing (s)-1,2,3,4-tetrahydroisoquinoline-1 carboxylic acid and derivatives thereof

A method for preparing an S-isomer of a compound represented by Formula (I),

• wherein:
• in Formula (I), R1 and R2 are independently selected from the group consisting of (i) hydrogen, (ii) C1-C6 alkyl, and (iii) C1-C6 alkoxy, and
• the method comprises the steps of:
• taking a racemate mixture of a compound represented by Formula (I) or salts thereof as a mixture, and
• making a R-isomer of the compound represented by Formula (I) in the substrate react under the catalysis of an oxidative dehydrogenase to generate an imino acid represented by Formula (II);
• wherein the oxidative dehydrogenase is a D-amino acid oxidase which has an amino acid sequence as shown in SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, or SEQ ID NO. 4;
• and
• converting the imino acid represented by Formula (II) into an S-isomer of the compound represented by the Formula (I) in the presence of a pipecolic acid reductase and a coenzyme capable of supplying hydrogen anions;
• and wherein:
• the pipecolic acid reductase has an amino acid sequence as shown in SEQ ID NO. 5, SEQ ID NO. 6, SEQ ID NO. 7, or SEQ ID NO. 8;
• and
• the coenzyme capable of supplying hydrogen anions is NADH, NADPH, or a combination thereof.