US3732245A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and intermediates for the preparation of indoles from ortho-nitrotoluenes
Assignee: F Hoffmann La Roche AG
•
Filing: 1970-11-04
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Granted: 1973-05-08
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Expires: 1990-11-04
Abstract
Abstract Ortho-nitrotoluenes are condensed with formamide acetals to yield the corresponding ortho-nitro- Beta -aminostyrenes which undergo cyclization upon reduction to yield indoles.
Inventors
- 👤 A Batcho
- 👤 W Leimgruber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:17
CPC Classifications
C; C07; C07D; C07D295/00; C07D295/04; C07D295/06; C07D295/073; C07C; C07C229/00; C07C229/38; C07D209/00; C07D209/02; C07D209/04; C07D209/08; C07D295/08; C07D295/096; C07D317/00; C07D317/08; C07D317/44; C07D317/46; C07D317/48; C07D317/62
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
8 words
A process for preparing indoles of the formula
Claim 2
Dependent Claim
17 words
A process in accordance with claim 2, wherein the formamide acetal is N,N-di-lower alkylformamide di-lower alkyl acetal.
Claim 3
Dependent Claim
18 words
A process in accordance with claim 3, wherein the condensation is carried out in a polar aprotic solvent.
Claim 4
Dependent Claim
14 words
A process in accordance with claim 4, wherein the polar aprotic solvent is N,N-dimethylformamide.
Claim 5
Dependent Claim
25 words
A process in accordance with claim 5, which comprises condensing o-nitrotoluene with N,N-dimethylformamide dimethyl acetal and reducing the resulting trans- Beta -dimethylamino-2-nitrostyrene to yield indole.
Claim 6
Dependent Claim
20 words
A process in accordance with claim 2 which comprises treating trans- Beta -dimethylamino-2-nitrostyrene with a reducing agent to yield indole.
Claim 7
Dependent Claim
20 words
A process in accordance with claim 2 which comprises treating trans-2-nitro- Beta -piperidinostyrene with a reducing agent to yield indole.
Claim 8
Dependent Claim
20 words
A process in accordance with claim 2 which comprises treating trans-2-nitro- Beta -pyrrolidinostyrene with a reducing agent to yield indole.
Claim 9
Dependent Claim
37 words
A process for preparing a compound having an indole nucleus which comprises simultaneously reducing the nitro function and removing the N,N-di-substituted amino function of a nitrobenzene derivative having a N,N-di-substituted aminovinyl function ortho to the nitro group.
Claim 10
Dependent Claim
34 words
A process in accordance with claim 10, wherein the nitrobenzene derivative having a N,N-di-substituted aminovinyl function is obtained by condensing the methyl function of an ortho-nitrotoluene with the formyl group of a formamide acetal.
Claim 11
Dependent Claim
14 words
A process for preparing an indole which comprises condensing an ortho-nitrotoluene of the formula
Claim 12
Dependent Claim
37 words
A process in accordance with claim 6, wherein the reduction is effected utilizing hydrogen and a catalyst selected from the group consisting of chromium, molybdenum, tungsten, platinum, palladium, rhodium, cobalt, nickel, ruthenium, their oxides, and combinations thereof.
Claim 13
Dependent Claim
12 words
A process in accordance with claim 13, wherein the catalyst is palladium.
Claim 14
Dependent Claim
13 words
A process in accordance with claim 2, wherein R1 and R2 are hydrogen.
Claim 15
Dependent Claim
45 words
A process in accordance with claim 2, which comprises treating trans- Beta -dimethylamino-2-nitrostyrene, trans-2-nitro- Beta -piperidinostyrene, or trans-2-nitro- Beta -pyrrolidinostyrene with hydrogen and a catalyst selected from the group consisting of chromium, molybdenum, tungsten, platinUm, palladium, rhodium, cobalt, nickel, ruthenium, their oxides and combinations thereof.
References Cited (Backward Citations)
US2752358A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |