US4140853A
Expired / Lapsed
US
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Process for the preparation of aminopyridines
Assignee: Bayer Pharma AG
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Filing: 1977-12-06
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Granted: 1979-02-20
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Expires: 1997-12-06
Abstract
Abstract A process for the preparation of aminopyridines of the formula ##STR1## wherein R 1 and R 2 are identical or different and are hydrogen or lower alkyl or, together with the nitrogen atom to which they are attached, form a 5-, 6-, or 7-membered heterocyclic ring containing up to 2 more hetero atoms, comprises reacting 4-pyridylpyridinium chloride or a salt thereof, at an elevated temperature, with an acid amide of the formula ##STR2## wherein R 1 and R 2 are as above and Z is --CO--R 3 wherein R 3 is hydrogen, lower alkyl, ##STR3## and R 4 and R 5 are hydrogen or lower alkyl.
Inventors
- 👤 Helmut Vorbrueggen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:48
CPC Classifications
C; C07; C07D; C07D213/00; C07D213/02; C07D213/04; C07D213/60; C07D213/72; C07D213/73; C07D213/74
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
126 words
A process for the preparation of aminopyridines which comprises the step of reacting, at about 120-220° C., 4-pyridyl-pyridinium chloride or a salt thereof with an acid amide of the formula ##STR13## wherein R 1 and R 2 each are hydrogen or lower alkyl or, collectively with the nitrogen atom to which they are attached, form a 5-, 6-, or 7-membered saturated heterocyclic ring containing 0 to 2 additional hetero atoms, selected from the group consisting of N, O and S, and wherein Z is --CO--R 3 and R 3 is hydrogen, lower alkyl, ##STR14## and R 4 and R 5 are hydrogen, or lower alkyl, to produce pyridine and an aminopyridine of the formula ##STR15## wherein R 1 and R 2 have the values given above.
Claim 2
Dependent Claim
126 words
A process for the preparation of aminopyridines which comprises the step of reacting, at about 120-220° C., 4-pyridyl-pyridinium chloride or a salt thereof with an acid amide of the formula ##STR13## wherein R 1 and R 2 each are hydrogen or lower alkyl or, collectively with the nitrogen atom to which they are attached, form a 5-, 6-, or 7-membered saturated heterocyclic ring containing 0 to 2 additional hetero atoms, selected from the group consisting of N, O and S, and wherein Z is --CO--R 3 and R 3 is hydrogen, lower alkyl, ##STR14## and R 4 and R 5 are hydrogen, or lower alkyl, to produce pyridine and an aminopyridine of the formula ##STR15## wherein R 1 and R 2 have the values given above.
Claim 3
Dependent Claim
14 words
The process of claim 1, wherein R 1 and R 2 each are hydrogen.
Claim 4
Dependent Claim
18 words
The process of claim 1, wherein R 1 and R 2 each are alkyl of 1-6 carbon atoms.
Claim 5
Dependent Claim
28 words
The process of claim 1, wherein R 1 and R 2 together with the nitrogen atom to which they are attached form a heterocyclic ring as defined therein.
Claim 6
Dependent Claim
14 words
The process of claim 1, wherein R 1 and R 2 collectively are tetramethylene.
Claim 7
Dependent Claim
14 words
The process of claim 1, wherein R 1 and R 2 collectively are pentamethylene.
Claim 8
Dependent Claim
14 words
The process of claim 1, wherein R 1 and R 2 collectively are hexamethylene.
Claim 9
Dependent Claim
22 words
The process of claim 1, wherein R 1 and R 2 collectively are --CH 2 CH 2 OCH 2 CH 2 --.
Claim 10
Dependent Claim
22 words
The process of claim 1, wherein R 1 and R 2 collectively are --CH 2 CH 2 SCH 2 CH 2 --.
Claim 11
Dependent Claim
25 words
The process of claim 1, wherein R 1 and R 2 collectively are ##STR16## and R 6 is hydrogen or alkyl of 1-6 carbon atoms.
Claim 12
Dependent Claim
21 words
The process of clain 1, wherein Z is --COR 3 and R 3 is hydrogen or alkyl of 1-6 carbon atoms.
Claim 13
Dependent Claim
21 words
The process of clain 1, wherein Z is --COR 3 and R 3 is hydrogen or alkyl of 1-6 carbon atoms.
Claim 14
Dependent Claim
29 words
The process of claim 1, wherein Z is --COR 3 , R 3 is ##STR17## and R 4 and R 5 are hydrogen or alkyl of 1-6 carbon atoms.
Claim 15
Dependent Claim
29 words
The process of claim 1, wherein Z is --COR 3 , R 3 is ##STR18## and R 4 and R 5 are hydrogen or alkyl of 1-6 carbon atoms.
Claim 16
Dependent Claim
13 words
The process of claim 1, wherein the acid amide is the reaction solvent.
Claim 17
Dependent Claim
15 words
The process of claim 1, wherein the reaction is conducted in the fused acid amide.
Claim 18
Dependent Claim
11 words
The process of claim 1, wherein 4-pyridyl-pyridinium chloride hydrochloride is employed.
Claim 19
Dependent Claim
19 words
The process of claim 1, wherein the pyridine produced by the reaction is removed continuously from the reaction mixture.
Claim 20
Dependent Claim
15 words
The process of claim 1, which further comprises the step of isolating the thus-produced aminopyridine.
Claim 21
Dependent Claim
25 words
The process of claim 18, wherein the isolating step comprises adding excess aqueous alkali to the reaction mixture prior to physical separation of the product.
Claim 22
Dependent Claim
18 words
The process of claim 18, which further comprises separating the isolated product by steam distillation or exhaustive extraction.
Claim 23
Dependent Claim
16 words
The process of claim 1, wherein the reacting step is conducted for at least one hour.
Claim 24
Dependent Claim
14 words
The process of claim 1, wherein the reacting step is conducted for 1-3.5 hours.
Claim 25
Dependent Claim
12 words
The process of claim 1, wherein the reaction temperature is 180-220° C.
Claim 26
Dependent Claim
12 words
The process of claim 1, wherein the reaction temperature is 140-220° C.
Claim 27
Dependent Claim
21 words
The process of claim 17, wherein the pyridine by-product is continuously removed from the reaction mixture during the reaction by distillation.
Claim 28
Dependent Claim
14 words
The process of claim 25, wherein the pyridine by-product is removed by column distillation.
Claim 29
Dependent Claim
19 words
The process of claim 1, wherein the starting reaction medium consists essentially of 4-pyridyl-pyridinium chloride and one acid amide.
Claim 30
Dependent Claim
19 words
The process of claim 11, wherein the starting reaction medium consists essentially of 4-pyridyl-pyridinium chloride and one acid amide.
Claim 31
Dependent Claim
19 words
The process of claim 12, wherein the starting reaction medium consists essentially of 4-pyridyl-pyridinium chloride and one acid amide.
Claim 32
Dependent Claim
17 words
The process of claim 28, wherein the starting reaction medium consists essentially of 4-pyridyl-pyridinium chloride and dimethylformamide.
Claim 33
Dependent Claim
17 words
The process of claim 29, wherein the starting reaction medium consists essentially of 4-pyridyl-pyridinium chloride and urea.
Claim 34
Dependent Claim
15 words
The process of claim 1, whereby a substantial amount of amino pyridine product is produced.
Claim 35
Dependent Claim
23 words
The process of claim 1, wherein the reaction is conducted until more than half of the 4-pyridyl-pyridinium chloride is converted to aminopyridine 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) | 1982-02-19 | 1982-08-21 | 1983-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-19 | 1986-08-21 | 1987-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-19 | 1990-08-21 | 1991-02-20 | $7700.00 | Window Closed / Lapsed |