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US4322359A
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Process for the preparation of 2,5-dimethyl-1,4: 3,6-dianhydrosorbitol
Assignee: Wyeth Holdings LLC
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Filing: 1981-03-19
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Granted: 1982-03-30
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Expires: 2001-03-19
Abstract
Abstract A water-miscible, non-hydroxylic, organic solvent is employed in the production of 2,5-dimethyl-1,4: 3,6-dianhydrosorbitol by methylation of 1,4: 3,6-dianhydrosorbitol with dimethyl sulfate.
Inventors
- 👤 Ray L. Hillard
- 👤 Irwin D. Greene
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:44
CPC Classifications
C; C07; C07D; C07D493/00; C07D493/02; C07D493/04
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
60 words
A process for the preparation of 2,5-dimethyl-1,4:3,6-dianhydrosorbitol from 1,4:3,6-dianhydrosorbitol by methylation with dimethyl sulfate, which comprises adding a stoichiometric excess of dimethyl sulfate to a solution of an alkali metal base and 1,4:3,6-dianhydrosorbitol in a water-miscible, non-hydroxylic organic solvent at a temperature of from about 25° C. to the boiling point of the solvent and recovering the resultant 2,5-dimethyl 1,4:3,6-dianhydrosorbitol.
Claim 2
Dependent Claim
60 words
A process for the preparation of 2,5-dimethyl-1,4:3,6-dianhydrosorbitol from 1,4:3,6-dianhydrosorbitol by methylation with dimethyl sulfate, which comprises adding a stoichiometric excess of dimethyl sulfate to a solution of an alkali metal base and 1,4:3,6-dianhydrosorbitol in a water-miscible, non-hydroxylic organic solvent at a temperature of from about 25° C. to the boiling point of the solvent and recovering the resultant 2,5-dimethyl 1,4:3,6-dianhydrosorbitol.
Claim 3
Dependent Claim
12 words
A process in accordance with claim 1 wherein the solvent is acetone.
Claim 4
Dependent Claim
15 words
A process in accordance with claim 1 wherein the alkali metal base is sodium hyroxide.
Claim 5
Dependent Claim
15 words
A process in accordance with claim 1 wherein the alkali metal base is potassium hydroxide.
Claim 6
Dependent Claim
76 words
A process for the preparation of 2,5-dimethyl-1,4:3,6-dianhydrosorbitol from 1,4:3,6-dianhydrosorbitol which comprises adding a stoichiometric excess of dimethyl sulfate to a solution of 1,4:3,6-dianhydrosorbitol and an alkali metal base in a water-miscible, non-hydroxylic organic solvent at a temperature of from about 25° C. to the boiling point of the solvent; removing the solvent from the reaction mixture; extracting the aqueous solution of crude 2,5-dimethyl-1,4:3,6-dianhydrosorbitol; removing the methylene chloride from the extracted solution thereof, and purifying the product.
Claim 7
Dependent Claim
76 words
A process for the preparation of 2,5-dimethyl-1,4:3,6-dianhydrosorbitol from 1,4:3,6-dianhydrosorbitol which comprises adding a stoichiometric excess of dimethyl sulfate to a solution of 1,4:3,6-dianhydrosorbitol and an alkali metal base in a water-miscible, non-hydroxylic organic solvent at a temperature of from about 25° C. to the boiling point of the solvent; removing the solvent from the reaction mixture; extracting the aqueous solution of crude 2,5-dimethyl-1,4:3,6-dianhydrosorbitol; removing the methylene chloride from the extracted solution thereof, and purifying the product.
Claim 8
Dependent Claim
20 words
A process in accordance with claim 5 wherein the solvent is recovered and recycled for use in the methylation reaction.
Claim 9
Dependent Claim
21 words
A process in accordance with claim 5 wherein the extraction is effected with methylene chloride and the organic solvent is acetone.
Claim 10
Dependent Claim
21 words
A process in accordance with claim 7 wherein the methylene chloride is recovered and recycled for use in the extraction step.
Claim 11
Dependent Claim
14 words
A process in accordance with claim 5 wherein the solvent is removed by distillation.
Claim 12
Dependent Claim
15 words
A process in accordance with claim 5 wherein the product is purified by vacuum distillation.
References Cited (Backward Citations)
US4169152A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-03-29 | 1985-09-28 | 1986-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-29 | 1989-09-28 | 1990-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-29 | 1993-09-28 | 1994-03-30 | $7700.00 | Window Closed / Lapsed |