Patent US3931191A successfully refreshed from Google Patents.
US3931191A
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Conversion of tetrahydropyrimidines to pyridines
Assignee: Baker Petrolite LLC
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Filing: 1973-08-01
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Granted: 1976-01-06
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Expires: 1993-08-01
Abstract
Abstract A process of converting 2,3,4,5-tetrahydropyrimidines containing at least 1 hydrogen in the 2-position and at least one methylene group in the 4-position to corresponding pyridines which comprises heating said tetrahydropyrimidines to a temperature sufficiently high to remove ammonia and hydrogen so as to form said pyridines.
Inventors
- 👤 Bernardus A. Oude Alink
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:57
CPC Classifications
C; C07; C07D; C07D213/00; C07D213/02; C07D213/04; C07D213/06; C07D213/08; C07D239/00; C07D239/02; C07D239/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
70 words
The process of converting a 2,3,4,5-tetrahydropyrimidine of the formula ##SPC4## wherein R 1 , R 2 , R 3 , R 4 , and R 5 may be the same or different are hydrogen, alkyl, aryl, cycloalkyl, alkaryl, aralkyl or heterocyclic to the corresponding pyridine which comprises heating said tetrahydropyrimidine to a temperature between 75°C. and 350°C. sufficiently high to remove ammonia and hydrogen so as to form said pyridine.
Claim 2
Dependent Claim
70 words
The process of converting a 2,3,4,5-tetrahydropyrimidine of the formula ##SPC4## wherein R 1 , R 2 , R 3 , R 4 , and R 5 may be the same or different are hydrogen, alkyl, aryl, cycloalkyl, alkaryl, aralkyl or heterocyclic to the corresponding pyridine which comprises heating said tetrahydropyrimidine to a temperature between 75°C. and 350°C. sufficiently high to remove ammonia and hydrogen so as to form said pyridine.
Claim 3
Dependent Claim
12 words
The process of claim 1 where a Lewis Acid catalyst is employed.
Claim 4
Dependent Claim
14 words
The process of claim 2 where the Lewis Acid catalyst is an ammonium salt.
Claim 5
Dependent Claim
20 words
The process of claim 3 where the ammonium salt is an ammonium salt of an inorganic or an organic acid.
Claim 6
Dependent Claim
15 words
The process of claim 4 where the ammonium salt is ammonium chloride or ammonium acetate.
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) | 1979-01-05 | 1979-07-07 | 1980-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-05 | 1983-07-07 | 1984-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-05 | 1987-07-07 | 1988-01-06 | $7700.00 | Window Closed / Lapsed |