US3130204A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of gamma-pyrones
Assignee: Pfizer Inc
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Filing: 1962-02-07
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Granted: 1964-04-21
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Expires: 1982-02-07
Abstract
No abstract record available.
Inventors
- 👤 Bryce E Tate
- 👤 Robert L Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:39
CPC Classifications
C; C07; C07D; C07D309/00; C07D309/34; C07D309/36; C07D309/40; A; A23; A23L; A23L27/00; A23L27/20; A23L27/205; A23L27/2052
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
168 words
A PROCESS FOR THE PREPARATION OF MALTOL FROM KOJIC ACID WHICH COMPRISES ADJUSTING AN AQUEOUS KOJIC ACID SOLUTION TO A PH OF AT LEAST 10 WITH SODIUM HYDROXIDE, INTRODUCING OXYGEN INTO SAID SOLUTION IN THE PRESENCE OF A PALLADIUM CATALYST, MAINTAINING SAID MINIMUM PH DURING OXYGENATION, CONTINUING THE OXYGENATION UNTIL THE KOJIC ACID SODIUM SALT IS SUBSTANTIALLY COMPLETELY CONSUMED, SUBSEQUENTLY ADJUSTING THE PH TO A VALUE BELOW ABOUT 2.5 WITH MINERAL ACID, RECOVERING THE COMENIC ACID FORMED THEREBY, HEATING SAID COMENIC ACID IN DIPHENYL ETHER TO A TEMPERATURE OF AT LEAST ABOUT 230*C., MAINTAINING SAID TEMPERATURE UNTIL EVOLUTION OF CARBON DIOXIDE SUBSTANTIALLY CEASES, RECOVERING THE PYROMECONIC ACID FORMED THEREBY, ADDING AN APPROXIMATELY MOLECULAR EQUIVALENT OF FORMALDEHYDE TO AN AQUEOUS SOLUTION OF SAID PYROMECONIC ACID ADJUSTED TO A PH OF AT LEAST ABOUT 8, TREATING THE SOLUTION OF HYDROXYMALTOL FORMED THEREBY WHEREIN THE 3-HYDROXYL GROUP OF SAID HYDROXY-MALTOL IS PREDOMINANTLY IN THE UNIONIZED FORM WITH A ZINC AND HYDROCHLORIC ACID REDUCING AGENT, AND RECOVERING THE MALTOL WHICH IS FORMED.
Claim 2
Dependent Claim
168 words
A PROCESS FOR THE PREPARATION OF MALTOL FROM KOJIC ACID WHICH COMPRISES ADJUSTING AN AQUEOUS KOJIC ACID SOLUTION TO A PH OF AT LEAST 10 WITH SODIUM HYDROXIDE, INTRODUCING OXYGEN INTO SAID SOLUTION IN THE PRESENCE OF A PALLADIUM CATALYST, MAINTAINING SAID MINIMUM PH DURING OXYGENATION, CONTINUING THE OXYGENATION UNTIL THE KOJIC ACID SODIUM SALT IS SUBSTANTIALLY COMPLETELY CONSUMED, SUBSEQUENTLY ADJUSTING THE PH TO A VALUE BELOW ABOUT 2.5 WITH MINERAL ACID, RECOVERING THE COMENIC ACID FORMED THEREBY, HEATING SAID COMENIC ACID IN DIPHENYL ETHER TO A TEMPERATURE OF AT LEAST ABOUT 230*C., MAINTAINING SAID TEMPERATURE UNTIL EVOLUTION OF CARBON DIOXIDE SUBSTANTIALLY CEASES, RECOVERING THE PYROMECONIC ACID FORMED THEREBY, ADDING AN APPROXIMATELY MOLECULAR EQUIVALENT OF FORMALDEHYDE TO AN AQUEOUS SOLUTION OF SAID PYROMECONIC ACID ADJUSTED TO A PH OF AT LEAST ABOUT 8, TREATING THE SOLUTION OF HYDROXYMALTOL FORMED THEREBY WHEREIN THE 3-HYDROXYL GROUP OF SAID HYDROXY-MALTOL IS PREDOMINANTLY IN THE UNIONIZED FORM WITH A ZINC AND HYDROCHLORIC ACID REDUCING AGENT, AND RECOVERING THE MALTOL WHICH IS FORMED.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1967-04-21 | 1967-10-21 | 1968-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-04-21 | 1971-10-21 | 1972-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-04-21 | 1975-10-21 | 1976-04-21 | $7700.00 | Window Closed / Lapsed |