US3715365A
Expired / Lapsed
US
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Imidazole synthesis
Assignee: Texaco Inc
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Filing: 1971-02-08
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Granted: 1973-02-06
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Expires: 1991-02-08
Abstract
Abstract An improved process for preparing imidazoles by contacting glyoxal or methyl substituted derivatives thereof, formaldehyde, and an ammonium salt of an acid having an ionization constant greater than 1 X 10 3.
Inventors
- 👤 H Schulze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:32
CPC Classifications
C; C07; C07D; C07D233/00; C07D233/54
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
69 words
A process for preparing an imidazole comprising reacting glyoxal or pyruvaldehyde with formaldehyde, wherein said reacting is conducted in an aqueous medium at a pH equal or less than 7 in the presence of an ammonium salt of an acid having an ionization constant greater than 1 X 10 3 and wherein said acid is selected from sulfuric acid, oxalic acid, p-toluene sulfonic acid, hydrochloric acid, or phosphoric acid.
Claim 2
Dependent Claim
69 words
A process for preparing an imidazole comprising reacting glyoxal or pyruvaldehyde with formaldehyde, wherein said reacting is conducted in an aqueous medium at a pH equal or less than 7 in the presence of an ammonium salt of an acid having an ionization constant greater than 1 X 10 3 and wherein said acid is selected from sulfuric acid, oxalic acid, p-toluene sulfonic acid, hydrochloric acid, or phosphoric acid.
Claim 3
Dependent Claim
35 words
The process according to claim 1 wherein said reacting is conducted at a temperature within the range of about 20*C. to about 100*C. for a time in the range of about 0.5 to 24 hours.
Claim 4
Dependent Claim
31 words
The process according to claim 2 wherein said temperature is within the range of about 70*C. to about 95*C. and wherein said acid is selected from oxalic acid or sulfuric acid.
Claim 5
Dependent Claim
36 words
The process according to claim 2 wherein said reacting is conducted at a temperature in the range of about 70*C. to about 95*C., wherein pyruvaldehyde is employed, and wherein said acid is oxalic or sulfuric acid.
Claim 6
Dependent Claim
36 words
The process according to claim 2 wherein said reacting is conducted at a temperature in the range of about 70*C. to about 90*C., wherein glyoxal is employed, and wherein said acid is oxalic or sulfuric Acid.
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) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |