Patent US3987051A successfully refreshed from Google Patents.
US3987051A
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Method for producing 1-unsubstituted pyrazolo[3,4-b]pyridine ketones
Assignee: ER Squibb and Sons LLC
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Filing: 1975-04-16
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Granted: 1976-10-19
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Expires: 1995-04-16
Abstract
Abstract A new process for the production of pyrazolo-[3,4-b]pyridine ketones which are unsubstituted in the 1-position comprises reacting a 1-furanylmethylpyrazolo[3,4-b]pyridine ketone with an inorganic strong mineral acid like sulfuric acid, phosphoric acid or polyphosphoric acid.
Inventors
- 👤 Theodor Denzel
- 👤 Hans Joachim Schneider
- 👤 Hans Hoehn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:32
CPC Classifications
C; C07; C07D; C07D471/00; C07D471/02; C07D471/04
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
131 words
A process for the production of a compound of the formula ##SPC4## wherein R is hydrogen or lower alkyl; R 1 is lower alkoxy or ##EQU1## R 2 is lower alkyl, cyclo-lower alkyl, phenyl or substituted phenyl wherein the phenyl substituent is halo, lower alkyl or lower alkoxy; R 3 is hydrogen, lower alkyl or phenyl; and R 4 and R 5 each is hydrogen, lower alkyl, cyclo-lower alkyl, phenyl or phenyl-lower alkyl or together R 4 and R 5 join to form piperidine, pyrimidine, pyrazine or piperazine, which comprises reacting a compound of the formula ##SPC5## with about 3 to 20 parts of a strong inorganic acid at a temperature of about 30° to 90° C., neutralizing the reaction product with base and isolating the product from the reaction mixture.
Claim 2
Dependent Claim
131 words
A process for the production of a compound of the formula ##SPC4## wherein R is hydrogen or lower alkyl; R 1 is lower alkoxy or ##EQU1## R 2 is lower alkyl, cyclo-lower alkyl, phenyl or substituted phenyl wherein the phenyl substituent is halo, lower alkyl or lower alkoxy; R 3 is hydrogen, lower alkyl or phenyl; and R 4 and R 5 each is hydrogen, lower alkyl, cyclo-lower alkyl, phenyl or phenyl-lower alkyl or together R 4 and R 5 join to form piperidine, pyrimidine, pyrazine or piperazine, which comprises reacting a compound of the formula ##SPC5## with about 3 to 20 parts of a strong inorganic acid at a temperature of about 30° to 90° C., neutralizing the reaction product with base and isolating the product from the reaction mixture.
Claim 3
Dependent Claim
17 words
A process as in claim 1 wherein the acid is sulfuric acid, phosphoric acid or polyphosphoric acid.
Claim 4
Dependent Claim
12 words
A process as in claim 1 wherein the acid is sulfuric acid.
Claim 5
Dependent Claim
12 words
A process as in claim 1 wherein the acid is polyphosphoric acid.
Claim 6
Dependent Claim
27 words
A process as in claim 1 wherein in the starting material and the product R and R 3 each is hydrogen and R 1 is lower alkoxy.
Claim 7
Dependent Claim
27 words
A process as in claim 1 wherein in the starting material and the product R and R 3 each is hydrogen and R 1 is lower alkylamino.
Claim 8
Dependent Claim
19 words
A process as in claim 1 wherein in the starting material and the product R 2 is lower alkyl.
Claim 9
Dependent Claim
18 words
A process as in claim 1 wherein in the starting material and final product R 2 is phenyl.
Claim 10
Dependent Claim
42 words
A process for the production of 5-benzoyl-4-ethoxy-1H-pyrazolo[3,4-b]pyridine which comprizes reacting 5-benzoyl-4-ethoxy-1-(2-furanyl)methyl-1H-pyrazolo[3,4-b]pyridine with about 3 to 20 parts of polyphosphoric acid or sulfuric acid at a temperature of about 30° to 90° C., neutralizing the reaction product with base and isolating the product.
Claim 11
Dependent Claim
42 words
A process for the production of 5-benzoyl-4-ethoxy-1H-pyrazolo[3,4-b]pyridine which comprizes reacting 5-benzoyl-4-ethoxy-1-(2-furanyl)methyl-1H-pyrazolo[3,4-b]pyridine with about 3 to 20 parts of polyphosphoric acid or sulfuric acid at a temperature of about 30° to 90° C., neutralizing the reaction product with base and isolating the product.
Claim 12
Dependent Claim
39 words
A process for the production of 5-acetyl-4-ethoxy-1H-pyrazolo[3,4-b]pyridine which comprises reacting 5-acetyl-4-ethoxy-1-(2-furanyl)methyl-1H-pyrazolo[3,4-b]pyridine with about 3 to 20 parts of polyphosphoric acid at a temperature of about 30° to 90° C., neutralizing the reaction product with base and isolating the product.
Claim 13
Dependent Claim
39 words
A process for the production of 5-acetyl-4-ethoxy-1H-pyrazolo[3,4-b]pyridine which comprises reacting 5-acetyl-4-ethoxy-1-(2-furanyl)methyl-1H-pyrazolo[3,4-b]pyridine with about 3 to 20 parts of polyphosphoric acid at a temperature of about 30° to 90° C., neutralizing the reaction product with base and isolating the product.
Claim 14
Dependent Claim
32 words
A process for the production of 5-benzoyl-4-sec. butylamino-1H-pyrazolo[3,4-b]pyridine which comprises reacting 5-benzoyl-4-sec. butylamino-1-(2-furanyl)methyl-1H-pyrazolo[3,4-b]pyridine with about 3 to 20 parts of sulfuric acid, neutralizing the reaction product with base and isolating the product.
Claim 15
Dependent Claim
32 words
A process for the production of 5-benzoyl-4-sec. butylamino-1H-pyrazolo[3,4-b]pyridine which comprises reacting 5-benzoyl-4-sec. butylamino-1-(2-furanyl)methyl-1H-pyrazolo[3,4-b]pyridine with about 3 to 20 parts of sulfuric acid, neutralizing the reaction product with base and isolating the product.
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) | 1979-10-19 | 1980-04-19 | 1980-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-19 | 1984-04-19 | 1984-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-19 | 1988-04-19 | 1988-10-19 | $7700.00 | Window Closed / Lapsed |