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US4035423A
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Process for the preparation of 3,4-dialkoxyanilines
Assignee: Novartis Corp
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Filing: 1976-02-20
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Granted: 1977-07-12
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Expires: 1996-02-20
Abstract
Abstract A new process for the production of 3,4-dialkoxyanilines in which the two alkyl groups are different from each other is disclosed. The process comprises the stepwise introduction of the alkyl groups in different stages of the process by converting pyrocatechol into its monoalkyl ether, coupling said monoalkyl ether with a phenyldiazonium salt, alkylating the 3-alkoxy-4-hydroxy-azobenzene obtained to form 3,4-dialkoxyazobenzene and reductively cleaving the latter to the corresponding 3,4-dialkoxyaniline. The 3,4-dialkoxyanilines obtainable by the new process are valuable intermediates for the preparation of 4-hydroxy-6,7-dialkoxy-3-quinoline carboxylic acid esters which are excellent coccidiostats.
Inventors
- 👤 Jean-Jacques Gallay
- 👤 Ernst Aufderhaar
- 👤 Peter Labuhn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:22
CPC Classifications
C; C07; C07D; C07D215/00; C07D215/02; C07D215/16; C07D215/48; C07D215/54; C07D215/56
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
156 words
A process for the production of 3,4-dialkoxyanilines of formula I ##STR6## wherein (a) R 1 and R 2 are different from each other and each of R 1 and R 2 represents a member of the group consisting of C 1 -C 20 -alkyl and C 3 -C 6 -cycloalkyl-C 1 -C 4 -alkyl or (b) R 1 represents C 1 -C 4 alkyl and R 2 represents C 8 -C 10 alkyl, which comprises reacting pyrocatechol with a reactive ester of an alcohol derived from the group R 1 , to form the corresponding pyrocatechol monoether of formula II ##STR7## coupling this pyrocatechol monoether with a phenyl diazonium salt to give an azobenzene of formula III ##STR8## relating this azobenzene with a reactive ester of an alcohol derived from the group R 2 , to form a 3,4-dialkoxyazobenzene of formula IV ##STR9## and then reductively splitting this 3,4-dialkoxy azobenzene to a 3,4-dialkoxyaniline of formula I.
Claim 2
Dependent Claim
156 words
A process for the production of 3,4-dialkoxyanilines of formula I ##STR6## wherein (a) R 1 and R 2 are different from each other and each of R 1 and R 2 represents a member of the group consisting of C 1 -C 20 -alkyl and C 3 -C 6 -cycloalkyl-C 1 -C 4 -alkyl or (b) R 1 represents C 1 -C 4 alkyl and R 2 represents C 8 -C 10 alkyl, which comprises reacting pyrocatechol with a reactive ester of an alcohol derived from the group R 1 , to form the corresponding pyrocatechol monoether of formula II ##STR7## coupling this pyrocatechol monoether with a phenyl diazonium salt to give an azobenzene of formula III ##STR8## relating this azobenzene with a reactive ester of an alcohol derived from the group R 2 , to form a 3,4-dialkoxyazobenzene of formula IV ##STR9## and then reductively splitting this 3,4-dialkoxy azobenzene to a 3,4-dialkoxyaniline of formula I.
Claim 3
Dependent Claim
29 words
Process according to claim 1, wherein the reactive esters of alcohols derived from residues R 1 and R 2 employed are halides, sulphuric acid esters or sulphonic acid esters.
Claim 4
Dependent Claim
23 words
Process according to claim 1, wherein the reactive ester of an alcohol derived from the residue R 1 is reacted with excess pyrocatechol.
Claim 5
Dependent Claim
21 words
Process according to claim 1, wherein a phenyl diazonium salt is used which is derived from aniline, toluidine or sulphanilic acid.
Claim 6
Dependent Claim
42 words
Process according to claim 1, wherein the reductive cleavage of the azobenzene of formula IV is performed with a reducing agent selected from the group consisting of sodium dithionite, hydrogen sulphide or a salt thereof, sodium bisulphite, zinc and tin (II) chloride.
Claim 7
Dependent Claim
21 words
Process according to claim 1, wherein the reductive cleavage of the azobenzene of formula IV is performed with catalytically activated hydrogen.
Claim 8
Dependent Claim
35 words
A process according to claim 1 in which one of R 1 and R 2 is C 8 -C 16 alkyl and the other is C 3 -C 6 cycloalkyl C 1 -C 4 alkyl.
Claim 9
Dependent Claim
17 words
A process according to claim 7 in which R 1 is n-decyl and R 2 is cyclopropylmethyl.
Claim 10
Dependent Claim
25 words
A process according to claim 1 in which R 1 is C 1 -C 4 alkyl and R 2 is C 8 -C 10 alkyl.
Claim 11
Dependent Claim
17 words
A process according to claim 9 in which R 1 is ethoxy and R 2 is n-decyl.
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) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |