Patent US3933902A successfully refreshed from Google Patents.
US3933902A
Expired / Lapsed
US
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Method for the optical resolution of DL-αphenylglycine
Assignee: Asahi Kasei Corp
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Filing: 1972-12-11
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Granted: 1976-01-20
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Expires: 1992-12-11
Abstract
Abstract A method for obtaining an optically active α-phenylglycine benzenesulfonate by optical resolutions which comprises dissolving DL-α-phenylglycine benzenesulfonate in an aqueous solution of benzenesulfonic acid, cooling the resulting solution to a temperature sufficient to render the solution supersaturated, selectively crystallizing either optically active D- or L-α-phenylglycine benzenesulfonate in the presence of a seed of either D- or L-α-phenylglycine benzenesulfonate corresponding to the optically active α-phenylglycine benzenesulfonate to be crystallized out, and separating the resulting crystals from the liquid phase is disclosed.
Inventors
- 👤 Teiko Watanabe
- 👤 Shigeyoshi Hayashi
- 👤 Shunji Ouchi
- 👤 Saburo Senoo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:23
CPC Classifications
C; C07; C07B; C07B57/00; C07C; C07C309/00; C07C309/01; C07C309/28; C07C309/29; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/582
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
113 words
A method for obtaining an optically active α-phenylglycine benzenesulfonate by optical resolution which comprises dissolving DL-α-phenylglycine benzenesulfonate in an aqueous solution of benzenesulfonic acid having a concentration greater than 5g of benzenesulfonic acid per 100 g of water, rendering the solution supersaturated, selectively crystallizing either optically active D- or L-α-phenylglycine benzenesulfonate, crystallization at least being initiated in the presence of a seed of either D- or L-α-phenylglycine benzensulfonate corresponding optically to the optically active α-phenylglycine benzenesulfonate to be crystallized out, and separating the resulting crystals from the liquid phase before initiation of crystallization of the optically active α-phenylglycine benzenesulfonate having an optical activity opposite to that of the crystallized optically active α-phenylglycine benzenesulfonate.
Claim 2
Independent Claim
113 words
A method for obtaining an optically active α-phenylglycine benzenesulfonate by optical resolution which comprises dissolving DL-α-phenylglycine benzenesulfonate in an aqueous solution of benzenesulfonic acid having a concentration greater than 5g of benzenesulfonic acid per 100 g of water, rendering the solution supersaturated, selectively crystallizing either optically active D- or L-α-phenylglycine benzenesulfonate, crystallization at least being initiated in the presence of a seed of either D- or L-α-phenylglycine benzensulfonate corresponding optically to the optically active α-phenylglycine benzenesulfonate to be crystallized out, and separating the resulting crystals from the liquid phase before initiation of crystallization of the optically active α-phenylglycine benzenesulfonate having an optical activity opposite to that of the crystallized optically active α-phenylglycine benzenesulfonate.
Claim 3
Dependent Claim
32 words
A method according to claim 1, wherein said aqueous solution of benzenesulfonic acid has a concentration in the range of 5 g to 30 g benzenesulfonic acid per 100 g of water.
Claim 4
Dependent Claim
14 words
A method according to claim 1, wherein said supersaturation is greater than 105% saturation.
Claim 5
Dependent Claim
19 words
A process according to claim 1, wherein said supersaturation is in the range of from 105% to 150% saturation.
Claim 6
Dependent Claim
87 words
A method according to claim 1, wherein said seed is prepared by adding crystals of DL-α-phenylglycine to an aqueous solution of an optically active α-phenylglycine benzenesulfonate, saturating the resulting solution with respect to total DL-α-phenylglycine benzenesulfonate, thereby crystallizing α-phenylglycine benzenesulfonate having the same optical activity as that of the α-phenylglycine benzenesulfonate initially present in the solution and separating the resulting crystals, said crystals of DL-β-phenylglycine being added in an amount of at least 2 times the amount of the optically active α-phenylglycine initially present in the solution.
Claim 7
Dependent Claim
30 words
A method according to claim 1, wherein said seed is used in an amount of from 5 to 100% by weight based on the weight of the dissolved DL-α-phenylglycine benzenesulfonate.
Claim 8
Dependent Claim
82 words
A method according to claim 1, wherein said crystallized product comprises optically active α-phenylglycine benzenesulfonate contaminated with DL-α-phenylglycine benzenesulfonate, and said method comprises the additional step of dissolving the contaminated optically active α-phenylglycine benzenesulfonate in an aqueous solution of benzenesulfonic acid having a concentration greater than 5 g per 100 g of water, substantially saturating the solution with respect to DL-α-phenylglycine benzenesulfonate contained therein, thereby crystallizing out said optically active α-phenylglycine benzenesulfonate, and separating the resulting optically purified crystals of α-phenylglycine benzenesulfonate.
Claim 9
Dependent Claim
42 words
A method according to claim 1, wherein said method further comprises saturating said liquid phase containing an optically active α-phenylglycine benzenesulfonate and DL-α-phenylglycine benzenesulfonate with respect to DL-α-phenylglycine benzenesulfonate without adding additional DL-α-phenylglycine benzenesulfonate thereby crystallizing out said optically active α-phenylglycine benzenesulfonate.
Claim 10
Dependent Claim
17 words
A method according to claim 1, wherein said saturation is carried out by cooling the liquid phase.
Claim 11
Dependent Claim
64 words
A method according to claim 1, which further comprises heating the resulting optically active α-phenylglycine benzenesulfonate having an undesired optical activity in an aqueous solution of benzenesulfonic acid having a concentration greater than 5 g per 100 g of water at a temperature in the range of from 110° to 200°C under pressurized condition in a sealed vessel to obtain a racemic DL-α-phenylglycine benzenesulfonate.
Claim 12
Independent Claim
46 words
A method for the racemization of L-α-phenylglycine which comprises heating L-α-phenylglycine at a temperature in the range of from 180° to 220°C in the presence of water in an amount of from 0.5 to 50 parts by weight per 1 part by weight of said L-α-phenylglycine.
Claim 13
Independent Claim
46 words
A method for the racemization of L-α-phenylglycine which comprises heating L-α-phenylglycine at a temperature in the range of from 180° to 220°C in the presence of water in an amount of from 0.5 to 50 parts by weight per 1 part by weight of said L-α-phenylglycine.
Claim 14
Dependent Claim
52 words
A method according to claim 1, wherein said method further comprises adding the resulting crystals of optically active α-phenylglycine benzenesulfonate to water in an amount of from 0.5 to 50 parts by weight per 1 part by weight of said α-phenylglycine benzenesulfonate to obtain an optically active free α-phenylglycine and benzenesulfonic acid.
Claim 15
Dependent Claim
30 words
A method according to claim 1, wherein said seed is used in an amount of from 5 to 20% by weight based on the weight of the dissolved DL-α-phenylglycine benzenesulfonate.
Claim 16
Dependent Claim
42 words
A method according to claim 1, wherein said method further comprises saturating said liquid phase containing an optically active α-phenylglycine benzenesulfonate and DL-α-phenylglycine benzenesulfonate with respect to DL-α-phenylglycine benzenesulfonate by adding additional DL-α-phenylglycine benzenesulfonate thereby crystallizing out said optically active α-phenylglycine benzenesulfonate.
References Cited (Backward Citations)
US3646082A
Cited
GB1210495A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-19 | 1979-07-21 | 1980-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-19 | 1983-07-21 | 1984-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-19 | 1987-07-21 | 1988-01-20 | $7700.00 | Window Closed / Lapsed |