US4340751A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of optical resolution of (±)-2-amino-1-butanol and/or (±)-mandelic acid
Assignee: Individual
•
Filing: 1981-03-05
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Granted: 1982-07-20
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Expires: 2001-03-05
Abstract
Abstract (±)-2-Amino-1-butanol and/or (±)-mandelic acid are optically resolved with a high resolution efficiency and high optical purities by preferentially crystallizing out one of the pair of less soluble enantiomeric salts (or optical antipodes), namely (+)-2-amino-1-butanol-(+)-mandelic acid salt and (-)-2-amino-1-butanol-(-)-mandelic acid salt.
Inventors
- 👤 Hiroyuki Nohira
- 👤 Hiroshi Fujii
- 👤 Masami Yajima
- 👤 Rieko Fujimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:37
CPC Classifications
C; C07; C07C; C07C215/00; C07C215/02; C07C215/04; C07C215/06; C07C215/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
82 words
A method of optical resolution of at least one of (±)- 2-amino-1-butanol (AB) and (±)-mandelic acid (MA), which method comprises the steps of: (i) crystallizing out, from a solution containing (±)AB and (±)MA, one of the pair of (+)AB-(+)MA salt and (-)AB-(-)MA salt, both of which are contained in said solution and which are enantiomeric salts; (ii) separating the crystallized salt from the liquid; (iii) decomposing the enantiomeric salt into optically active AB and MA; and (iv) recovering the optically active substances.
Claim 2
Independent Claim
82 words
A method of optical resolution of at least one of (±)- 2-amino-1-butanol (AB) and (±)-mandelic acid (MA), which method comprises the steps of: (i) crystallizing out, from a solution containing (±)AB and (±)MA, one of the pair of (+)AB-(+)MA salt and (-)AB-(-)MA salt, both of which are contained in said solution and which are enantiomeric salts; (ii) separating the crystallized salt from the liquid; (iii) decomposing the enantiomeric salt into optically active AB and MA; and (iv) recovering the optically active substances.
Claim 3
Dependent Claim
24 words
A method of optical resolution according to claim 1, wherein the solution medium is selected from the group consisting of water, methanol and 2-propanol.
Claim 4
Dependent Claim
27 words
A method of optical resolution according to claim 1, wherein at least one of (+)AB, (-)AB, (+)MA and (-)MA coexists in the solution containing (±)AB and (±)MA.
Claim 5
Dependent Claim
89 words
A method of optical resolution according to claim 1, wherein the resolution starts from a mixture solution of AB and MA of the composition selected from the following (I) and (I'): ______________________________________
(I) (+) (or (-)) AB (a + b) mole
(±) AB (2a + 2b) mole
(±) MA (2a + b) mole
(±) MA (a + 2b) mole
(I') (+) (or (-)) MA (a + b) mole
(±) MA (2a + 2b) mole
(+) (or (-)) AB (2a + b) mole
(±) AB (a + 2b) mole.
______________________________________
Claim 6
Dependent Claim
39 words
A method of optical resolution according to claim 4, wherein the molar amounts of the components in the mixture solution are within the range of 0.7 to 1.3 times of the value given by the formulation (I) or (I').
Claim 7
Dependent Claim
270 words
A method of optical resolution according to claim 4, which comprises the steps of: (i) starting from the mixture solution of the composition selected from the above noted (I) and (I'), crystallizing out (2a+2b) mole of the enantiomeric salt, (+)AB-(-)MA or (-)AB-(-)MA, followed by separation of the crystal from the liquid; (ii) adding to the resulting mother liquor the mixture of racemic forms of both AB and MA and an optically active form of one of AB and MA of the composition selected from (II) and (II') below: ______________________________________
(II) (+) AB (2a + 2b) mole
(-) (or (+)) AB 2a mole
(±) MA 2b mole
(II') (±) MA (2a + 2b) mole
(-) (or (+)) MA 2a mole
(±) AB 2b mole
______________________________________ so as to crystallize out (2a+2b) mole of the enantiomeric salt of (-)AB-(-)MA or (+)AB-(+)MA, followed by separation of the crystal from the liquid; (iii) adding to the resulting secondary mother liquor the racemic forms of both AB and MA and an optically active form of one of AB and MA of the composition selected from (III) or (III') below: ______________________________________
(III) (±) AB (2a + 2b) mole
(±) (or (-)) AB
2a mole
(±) MA 2b mole
(III') (±) MA (2a + 2b) mole
(+) (or (-)) MA 2a mole
(±) AB 2b mole
______________________________________ so as to crystallize out (2a+2b) mole of the enantiomeric salt of (+)AB-(+)MA or (-)AB-(-)MA, followed by separation of the crystal from the liquid; and, (iv) repeating the above steps (ii) and (iii) sequentially, and finally, decomposing the obtained enantiomeric salts to optically active AB and MA, and recovering them.
Claim 8
Dependent Claim
45 words
A method of optical resolution according to claim 6, wherein the molar amounts of the components in the mixture are within the range of 0.7 to 1.3 times of the value given by the formulations (I) or (I'), (II) or (II'), and (III) or (III').
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-19 | 1986-01-18 | 1986-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-19 | 1990-01-18 | 1990-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-19 | 1994-01-18 | 1994-07-20 | $7700.00 | Window Closed / Lapsed |