Process for producing optically active octahydro-1H-indole-2-carboxylic acid
To provide an enzymatic resolution process for efficiently producing an optically active N-protected-octahydro-1H-indole-2-carboxylic acid denoted by the formula (2): by using an enzyme capable of asymmetrically hydrolyzing the —CO 2 R 1 group in the formula (1) wherein R 1 indicates an alkyl group having a carbon number of 1 to 4, R 2 indicates a protecting group of the imino group, and the carbon atoms marked with asterisks (*) indicate asymmetrical carbon atoms.
1. A process for producing an optically active N-protected-octahydro-1H-indole-2-carboxylic acid of formula (2):
wherein R 2 represents a protecting group of an imino group, and the carbon atoms denoted with asterisks (*) represent asymmetric carbon atoms, which process comprises
reacting a mixture of enantiomers of N-protected-octahydro-1H-indole-2-carboxylate of formula (1):
wherein R 1 is a C1-4 alkyl group, and R 2 is as defined above, with an enzyme capable of asymmetrically hydrolyzing the —CO 2 R 1 group of formula (1), wherein the enzyme is an enzyme
i) produced by a microorganism deposited with accession number FERM BP-6703,
ii) comprising a polypeptide sequence of SEQ ID NO:1, or
iii) comprising a polypeptide sequence of SEQ ID NO:1 modified by deletion, substitution or both of the amino acids selected from the group consisting of amino acid 160 of SEQ ID NO:1 and amino acid 189 of SEQ ID NO:1.
2. A process according to claim 1 , wherein the mixture of enantiomers of N-protected-octahydro-1H-indole-2-carboxylate of formula (1) is a mixture of a single enantiomer and an antipode thereof.
3. A process according to claim 2 , wherein the single enantiomer and antipode thereof are the compound of formula (1′) and the compound of formula (1″):
wherein R 1 is and R 2 are as defined in claim 1 .
4. A process according to claim 2 , which further comprises
isolating the antipode of the resulting asymmetrically hydrolyzed optically active N-protected-octahydro-1H-indole-2-carboxylic acid as an ester, and hydrolyzing the isolated optically active N-protected-octahydro-1H-indole-2-carboxylic acid ester to produce an antipode acid compound of the enantiomer of formula (2).
5. A process according to claim 4 , wherein the hydrolyzing of the N-protected-octahydro-1H-indole-2-carboxylate is conducted in the presence of an alkali.
6. A process according to claim 1 , wherein R 2 is a tert-butoxycarbonyl group, a benzyloxycarbonyl group, an acetyl group, a benzoyl group or a benzyl group.
7. A process according to claim 6 , wherein R 2 is a benzyloxycarbonyl group.
8. A process according to claim 1 , wherein R 1 is ethyl.
9. A process according to claim 1 , which further comprises the step of deprotecting the optically active N-protected-octahydro-1H-indole-2-carboxylic acid of formula (2) to produce corresponding optically active octahydro-1H-indole-2-carboxylic acid.