US4039555A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Benzofuran derivatives, process for preparing them and their use as optical brighteners
Assignee: Hoechst AG
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Filing: 1975-11-14
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Granted: 1977-08-02
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Expires: 1995-11-14
Abstract
Abstract Condensation of a benzofuran, which is substituted in 2-position by a carboxylic acid hydrazide group bound to the benzofuran nucleus via a bridgemember being in conjugation with the double bonds of the benzofuran, with a benzofuran-2-carboxylic acid halide yields a bisacyl hydrazide which is capable of oxdiazol ring closure while splitting off water. The so-obtained oxdiazoles are optical brighteners, especially for polyester materials.
Inventors
- 👤 Wilfried Sahm
- 👤 Erich Schinzel
- 👤 Gunter Rosch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:28
CPC Classifications
C; C07; C07D; C07D307/00; C07D307/77; C07D307/78; C07D307/79
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
46 words
A compound of the formula ##STR31## wherein E is p-phenylene, T and U are hydrogen or methyl; P, Q, V and W are hydrogen, chlorine, methyl or methoxy, or P and Q together or V and W together are a benzene ring annellated in the 4,5-position.
Claim 2
Dependent Claim
46 words
A compound of the formula ##STR31## wherein E is p-phenylene, T and U are hydrogen or methyl; P, Q, V and W are hydrogen, chlorine, methyl or methoxy, or P and Q together or V and W together are a benzene ring annellated in the 4,5-position.
Claim 3
Dependent Claim
23 words
The compound as defined in claim 1, wherein T and U are hydrogen, P is 6-methoxy and Q, V and W are hydrogen.
Claim 4
Dependent Claim
23 words
The compound as defined in claim 1, wherein T and U are hydrogen, P is 5-methyl and Q, V and W are hydrogen.
Claim 5
Dependent Claim
20 words
The compound as defined in claim 1, wherein U is methyl and T, P, Q, V and W are hydrogen.
Claim 6
Dependent Claim
22 words
The compound as defined in claim 1, wherein V is 5-methyl, W is 6-methyl and T, U, P and Q are hydrogen.
Claim 7
Dependent Claim
17 words
The compound as defined in claim 1, wherein T, U, P, Q, V and W are hydrogen.
Claim 8
Dependent Claim
28 words
The compound as defined in claim 1, wherein P and Q together are a phenyl ring annellated in 4,5 positions and T, U, V and W are hydrogen.
References Cited (Backward Citations)
US3900419A
Cited
US3772373A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-01 | 1981-01-31 | 1981-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-01 | 1985-01-31 | 1985-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-01 | 1989-01-31 | 1989-08-02 | $7700.00 | Window Closed / Lapsed |