US4124768A
Expired / Lapsed
US
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Process for preparing pure substituted 2,5-diarylamino-terephthalates and the corresponding free acids
Assignee: Hoechst AG
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Filing: 1976-09-22
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Granted: 1978-11-07
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Expires: 1996-09-22
Abstract
Abstract 2,5-Diarylamino terephthalates are obtained in good yields and excellent purity when the aromatic nitro compound used for oxidizing the corresponding dihydro-2,5-diarylamino terephthalate contains the aromatic radical of said diarylamino groups, i.e. when the amine formed during the oxidation is that from which said diarylamino groups device. The products yield very pure quinacridone pigments and allow the synthesis of only one isomer of substituted quinacridones.
Inventors
- 👤 Aloys Kirsch
- 👤 Otto Fuchs
- 👤 Ernst Spietschka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:06
CPC Classifications
C; C07; C07D; C07D403/00; C07D403/02; C07D403/06
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
194 words
In a process for the preparation of 2,5-diarylamino-lower alkyl-terephthalates of the formula ##STR5## in which R 1 and R 2 , which are the same or different, are alkyl of one to 4 carbon atoms and R has the formula ##STR6## in which R 3 , R 4 and R 5 are hydrogen, chlorine, bromine, fluorine, alkyl of one to four carbon atoms, alkoxy of one to four carbon atoms, phenyl or phenoxy or two of the substituents R 3 , R 4 and R 5 together stand for a fused benzene nucleus, with the proviso that at least one of the substituents R 3 , R 4 and R 5 is not hydrogen, each R having one free ortho-position with respect to the nitrogen atom, by oxidizing a dihydro-2,5-diaryl amino terephthalate of the formula ##STR7## in which R, R 1 and R 2 are as defined above, with a nitro-aromate in the presence of catalytic amounts of a strong mineral acid or a strong organic acid, the improvement comprising oxidizing said dihydro-2,5-diarylamino terephthalate with a nitro-aromate having the formula R -- NO.sub.2 in which R is the same as in said dihydro-2,5-diarylamino terephthalate.
Claim 2
Dependent Claim
194 words
In a process for the preparation of 2,5-diarylamino-lower alkyl-terephthalates of the formula ##STR5## in which R 1 and R 2 , which are the same or different, are alkyl of one to 4 carbon atoms and R has the formula ##STR6## in which R 3 , R 4 and R 5 are hydrogen, chlorine, bromine, fluorine, alkyl of one to four carbon atoms, alkoxy of one to four carbon atoms, phenyl or phenoxy or two of the substituents R 3 , R 4 and R 5 together stand for a fused benzene nucleus, with the proviso that at least one of the substituents R 3 , R 4 and R 5 is not hydrogen, each R having one free ortho-position with respect to the nitrogen atom, by oxidizing a dihydro-2,5-diaryl amino terephthalate of the formula ##STR7## in which R, R 1 and R 2 are as defined above, with a nitro-aromate in the presence of catalytic amounts of a strong mineral acid or a strong organic acid, the improvement comprising oxidizing said dihydro-2,5-diarylamino terephthalate with a nitro-aromate having the formula R -- NO.sub.2 in which R is the same as in said dihydro-2,5-diarylamino terephthalate.
Claim 3
Dependent Claim
35 words
A process as claimed in claim 1, wherein the nitro-aromate is selected from the group consisting of o-, m- and p-chloro-, -bromo-, -fluoro-, -methyl- and -methoxy-nitrobenzene, 2-chloro-4-methyl-nitrobenzene, 3-chloro-4-methyl-nitrobenzene, 2,4-dichloro-nitrobenzene, 2,3-dichloro-nitrobenzene or 2,3,4-trichloro-nitrobenzene, 1-nitronaphthalene and 2-nitronaphthalene.
Claim 4
Dependent Claim
16 words
A process as claimed in claim 1, wherein the substituent different from hydrogen is in ortho-position.
Claim 5
Dependent Claim
30 words
A process as claimed in claim 1, wherein only one of the substituents R 3 , R 4 and R 5 is different from hydrogen and linked to the paraposition.
Claim 6
Dependent Claim
33 words
A process as claimed in claim 1, wherein two of the substituents R 3 , R 4 and R 5 are different from hydrogen, are identical and linked to the 3- and 5-positions.
Claim 7
Dependent Claim
38 words
A process as claimed in claim 5, wherein all of the substituents R 3 , R 4 and R 5 are different from hydrogen, two identical substituents are in the 3- and 5-positions and the third in 4-position.
Claim 8
Dependent Claim
21 words
A process as claimed in claim 1, wherein the oxidation is performed at a temperature of about 110° to 150° C.
Claim 9
Dependent Claim
15 words
A process as claimed in claim 1, wherein the nitroaromate is added in an excess.
Claim 10
Dependent Claim
15 words
A process as claimed in claim 1, wherein catalytic amounts of said acid are present.
Claim 11
Dependent Claim
15 words
A process as claimed in claim 1, wherein said acid is acetic or trifluoroacetic acid.
Claim 12
Dependent Claim
18 words
A process as claimed in claim 1, wherein as a co-catalyst a secondary or tertiary amine is added.
Claim 13
Dependent Claim
12 words
A process as claimed in claim 11, wherein said co-catalyst is piperidine.
Claim 14
Dependent Claim
77 words
A process as claimed in claim 1, wherein the dihydro-2,5-diarylamino terephthalate is formed in situ by reacting a succinylo-succinic acid ester of the formula ##STR8## with at least 2 mols of an amine of the formula R -- NH.sub.2 at a temperature of about 75° to 120° C. in a reaction medium of the formula R -- NO.sub.2 in which R is the same as in said amine, in the presence of catalytic amounts of an acid.
Claim 15
Dependent Claim
25 words
A process as claimed in claim 13, wherein said dihydro-2,5-diarylamino terephthalate is formed in the presence of catalytic amounts of a secondary or tertiary amine.
Claim 16
Dependent Claim
22 words
A process as claimed in claim 1, wherein the reaction product is isolated by precipitating it with a low-molecular completely water-soluble alkanol.
Claim 17
Dependent Claim
43 words
A process as claimed in claim 1, wherein the reaction product is isolated as the alkalimetal salt of the free acid by adding the reaction mixture to an aqueous alkali metal hydroxide solution and maintaining a temperature of about 90° to 110° C.
Claim 18
Dependent Claim
14 words
A process as claimed in claim 16, which is performed in a closed vessel.
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) | 1981-11-06 | 1982-05-08 | 1982-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-06 | 1986-05-08 | 1986-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-06 | 1990-05-08 | 1990-11-07 | $7700.00 | Window Closed / Lapsed |