Patent US4028383A successfully refreshed from Google Patents.
US4028383A
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Indolopyrones having antiallergic activity
Assignee: Warner Lambert Co LLC
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Filing: 1975-09-08
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Granted: 1977-06-07
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Expires: 1995-09-08
Abstract
Abstract This invention relates to novel substituted indolopyrones which have utility in preventing allergic and asthmatic reactions in mammals.
Inventors
- 👤 Richard E. Brown
- 👤 Paul C. Unangst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:49
CPC Classifications
C; C07; C07D; C07D209/00; C07D209/02; C07D209/04; C07D209/30; C07D209/32; C07D209/36
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
62 words
A substituted indolopyrone of the formula: ##STR9## wherein R 1 and R 2 may be hydrogen, hydroxy, lower alkoxy or lower alkyl, halogen, trifluoromethyl, or taken together to form a methylenedioxy group; R 3 may be hydrogen, lower alkyl, phenyl; R 4 may be hydrogen, lower alkyl of 1 to 6 carbon atoms; and R 5 may be hydrogen or lower alkyl.
Claim 2
Dependent Claim
62 words
A substituted indolopyrone of the formula: ##STR9## wherein R 1 and R 2 may be hydrogen, hydroxy, lower alkoxy or lower alkyl, halogen, trifluoromethyl, or taken together to form a methylenedioxy group; R 3 may be hydrogen, lower alkyl, phenyl; R 4 may be hydrogen, lower alkyl of 1 to 6 carbon atoms; and R 5 may be hydrogen or lower alkyl.
Claim 3
Dependent Claim
28 words
The indolopyrones of claim 1 wherein R 1 , R 2 , R 3 , R 4 , and R 5 may be hydrogen, or a lower alkyl.
Claim 4
Dependent Claim
13 words
The indolopyrones of claim 2 wherein R 1 and R 2 are hydrogen.
Claim 5
Dependent Claim
17 words
The indolopyrones of claim 3 wherein R 3 is a lower alkyl and R 4 is hydrogen.
Claim 6
Dependent Claim
18 words
The indolopyrone of claim 4 wherein R 5 is C 2 H 5 and which is Ethyl 4,5-dihydro-5-methyl-4-oxopyrano[3,2-b]-indole-2-carboxylate.
Claim 7
Dependent Claim
15 words
The indolopyrone of claim 4 wherein R 5 is hydrogen and which is 4,5-dihydro-5-methyl-4-oxopyrano[3,2-b]indole-2-carboxylic acid.
Claim 8
Dependent Claim
117 words
A process for the preparation of an indolopyrone as defined in claim 1 comprising the steps of: A. reacting a compound of the formula: ##STR10## wherein R 6 is a lower alkyl of 1- 6 carbons with dimethylsulfone in the presence of a strong base; B. reacting the compound so obtained with a lower alkyl halide or tosylate in the presence of a strong base to obtain a compound of the structure: ##STR11## C. Reacting the compound so obtained in the presence of an organic acid to obtain the compound: ##STR12## D. Reacting the compound so obtained with a lower alkyl ester of oxalic acid in the presence of a strong base to obtain the desired compound.
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) | 1980-06-06 | 1980-12-06 | 1981-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-06 | 1984-12-06 | 1985-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-06 | 1988-12-06 | 1989-06-07 | $7700.00 | Window Closed / Lapsed |