Patent US4198501A successfully refreshed from Google Patents.
US4198501A
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US
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Synthesis of tryptophans
Assignee: DSM Nutritional Products LLC
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Filing: 1978-10-30
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Granted: 1980-04-15
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Expires: 1998-10-30
Abstract
Abstract A process is disclosed for preparing racemic and optically pure tryptophans through novel intermediates.
Inventors
- 👤 Andrew D. Batcho
- 👤 Willy Leimgruber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:22
CPC Classifications
C; C07; C07D; C07D209/00; C07D209/02; C07D209/04; C07D209/10; C07D209/18; C07D209/20; C07D263/00; C07D263/02; C07D263/30; C07D263/34; C07D263/36; C07D263/42; C07D309/00; C07D309/34; C07D309/36; C07D309/38
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
91 words
A process for the preparation of a compound of the formula: ##STR4## wherein R 1 and R 16 individually are halogen, lower alkyl, hydroxy, lower alkoxy, aralkyloxy, amino, trihalomethyl or hydrogen and R 9 is lower alkyl, aryl, hydrogen or halo-lower alkyl, which comprises catalytically reducing a compound of the formula: ##STR5## wherein R 1 , R 9 and R 16 are described above, with a catalyst selected from the group consisting of oxides of chromium, molybdenum, tungsten, platinum, palladium, rhodium, cobalt, nickel and ruthenium, in the presence of a solvent.
Claim 2
Dependent Claim
91 words
A process for the preparation of a compound of the formula: ##STR4## wherein R 1 and R 16 individually are halogen, lower alkyl, hydroxy, lower alkoxy, aralkyloxy, amino, trihalomethyl or hydrogen and R 9 is lower alkyl, aryl, hydrogen or halo-lower alkyl, which comprises catalytically reducing a compound of the formula: ##STR5## wherein R 1 , R 9 and R 16 are described above, with a catalyst selected from the group consisting of oxides of chromium, molybdenum, tungsten, platinum, palladium, rhodium, cobalt, nickel and ruthenium, in the presence of a solvent.
Claim 3
Dependent Claim
85 words
A process for the preparation of a compound of the formula: ##STR6## wherein R 1 and R 16 individually are halogen, lower alkyl, hydroxy, lower alkoxy, aralkyloxy, amino, trihalomethyl or hydrogen and R 9 is lower alkyl, aryl, hydrogen or halo-lower alkyl, which comprises chemically reducing a compound of the formula: ##STR7## wherein R 1 , R 9 and R 16 are described above, with a reducing agent selected from the group consisting of zinc dust and iron dust, in the presence of a solvent.
Claim 4
Dependent Claim
85 words
A process for the preparation of a compound of the formula: ##STR6## wherein R 1 and R 16 individually are halogen, lower alkyl, hydroxy, lower alkoxy, aralkyloxy, amino, trihalomethyl or hydrogen and R 9 is lower alkyl, aryl, hydrogen or halo-lower alkyl, which comprises chemically reducing a compound of the formula: ##STR7## wherein R 1 , R 9 and R 16 are described above, with a reducing agent selected from the group consisting of zinc dust and iron dust, in the presence of a solvent.
Claim 5
Dependent Claim
13 words
The process of claim 1 wherein the catalytic reduction employs a platinum catalyst.
Claim 6
Dependent Claim
21 words
The process of claim 2 wherein the chemical reduction occurs in the presence of an organic acid and an acid anhydride.
Claim 7
Dependent Claim
12 words
The process of claim 4 wherein the organic acid is acetic acid.
Claim 8
Dependent Claim
12 words
The process of claim 4 wherein the acid anhydride is acetic anhydride.
Claim 9
Dependent Claim
21 words
The process of claim 2 wherein the chemical reduction employs zinc dust in the presence of acetic acid and acetic anhydride.
Claim 10
Dependent Claim
12 words
The process of claim 1 or 2 wherein R 1 is methyl.
Claim 11
Dependent Claim
12 words
The process of claim 1 or 2 wherein R 9 is methyl.
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) | 1983-04-15 | 1983-10-15 | 1984-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-15 | 1987-10-15 | 1988-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-15 | 1991-10-15 | 1992-04-15 | $7700.00 | Window Closed / Lapsed |