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US4550182A
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Preparation of α-tocopherol
Assignee: BASF SE
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Filing: 1984-03-12
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Granted: 1985-10-29
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Expires: 2004-03-12
Abstract
Abstract A process for the preparation of α-tocopherol of the formula I ##STR1## by reacting a chroman derivative with a C 14 -Grignard reagent using a di-alkali metal tetrahalocuprate catalyst in a Schlosser-Fouquet reaction, wherein a chroman derivative of the general formula II ##STR2## where Y is a leaving group, especially Br, is used and is reacted, at from -70° to 0° C., first with a solution of about 1 equivalent of a Grignard compound of the general formula III X--Mg--R (III) where X is Cl, Br or I and R is straight-chain or branched alkyl of 1 to 14 carbon atoms, preferably methyl, ethyl or ##STR3## and then with a solution of a Grignard reagent of the formula IIIa ##STR4## in an ether solvent and a solution of a di-alkali metal tetrahalocuprate in an ether solvent. The novel process simplifies the preparation of 2RS,4'RS,8'RS-, 2R,4'RS,8'RS- or 2R,4'R,8'R-α-tocopherol by reacting a chroman structural unit, containing a C 2 side-chain in the 2-position, with the corresponding C 14 -Grignard compound.
Inventors
- 👤 Hansgeorg Ernst
- 👤 Henning-Peter Gehrken
- 👤 Joachim Paust
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:28
CPC Classifications
C; C07; C07D; C07D311/00; C07D311/02; C07D311/04; C07D311/58; C07D311/70; C07D311/72
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
156 words
A process for the preparation of α-tocopherol of the formula I ##STR12## by reacting a chroman derivative with a C 14 -Grignard reagent using a di-alkali metal tetrahalocuprate catalyst in a Schlosser-Fouquet reaction, wherein (a) a chroman derivative of the formula II ##STR13## where Y is one of the leaving groups --Br, --I, -p-tosyl or benzenesulfonyl, especially --Br, is used and is reacted, at from -70° to 0° C., (b) first with a solution of from 0.8 to 1.1 equivalent of a Grignard reagent of the formula III X--Mg--R (III) where X is Cl, Br or I and R is straight-chain or branched alkyl of 1 to 14 carbon atoms, preferably methyl, ethyl or ##STR14## and then (c) with a solution of from 1.05 to 2 equivalents of a Grignard reagent of the formula IIIa ##STR15## in an ether solvent and in the presence of a solution of a di-alkali metal tetrahalocuprate in an ether solvent.
Claim 2
Dependent Claim
156 words
A process for the preparation of α-tocopherol of the formula I ##STR12## by reacting a chroman derivative with a C 14 -Grignard reagent using a di-alkali metal tetrahalocuprate catalyst in a Schlosser-Fouquet reaction, wherein (a) a chroman derivative of the formula II ##STR13## where Y is one of the leaving groups --Br, --I, -p-tosyl or benzenesulfonyl, especially --Br, is used and is reacted, at from -70° to 0° C., (b) first with a solution of from 0.8 to 1.1 equivalent of a Grignard reagent of the formula III X--Mg--R (III) where X is Cl, Br or I and R is straight-chain or branched alkyl of 1 to 14 carbon atoms, preferably methyl, ethyl or ##STR14## and then (c) with a solution of from 1.05 to 2 equivalents of a Grignard reagent of the formula IIIa ##STR15## in an ether solvent and in the presence of a solution of a di-alkali metal tetrahalocuprate in an ether solvent.
Claim 3
Dependent Claim
54 words
A process for the preparation of α-tocopherol of the formula I as claimed in claim 1, wherein the reaction of the chroman derivative of formula II with the solution of the Grignard reagent of the formula III and the Grignard reagent of the formula IIIa is carried out at from -25° to -15° C.
Claim 4
Dependent Claim
42 words
A process for the preparation of α-tocopherol of the formula I as claimed in claim 1, wherein the reaction with the solution of the Grignard reagent of the formula IIIa is carried out in the presence of a solution of di-lithium tetrachlorocuprate.
Claim 5
Dependent Claim
28 words
A process as claimed in claim 1, wherein, to prepare (2R,4'RS,8'RS)-α-tocopherol, an ether solution of (2S)-2,5,7,8-tetramethyl-6-hydroxy-2-(2'-bromoethyl)chroman is reacted, in step (c), with a solution of a (2RS,6RS)-2,6,10-trimethyl-1-undecyl-magnesium halide.
Claim 6
Dependent Claim
28 words
A process as claimed in claim 1, wherein, to prepare (2R,4'R,8'R)-α-tocopherol, an ether solution of (2S)-2,5,7,8-tetramethyl-6-hydroxy-2-(2'-bromoethyl)chroman is reacted, in step (c), with a solution of a (2R,6R)-2,6,10-trimethyl-1-undecyl-magnesium halide.
Claim 7
Dependent Claim
22 words
The process of claim 1, wherein the ether solvent comprises tetrahydrofuran, dioxane, diethylether, dimethoxyethane, diethylene glycol dimethyl ether or a mixture thereof.
Claim 8
Dependent Claim
11 words
The process of claim 1, wherein the ether solvent comprises tetrahydrofuran.
Claim 9
Dependent Claim
15 words
The process of claim 1, wherein R is methyl or ethyl, and X is Br.
Claim 10
Dependent Claim
21 words
The process of claim 1, wherein the two reactants of step (b) are reacted for from 15 minutes to 4 hours.
Claim 11
Dependent Claim
21 words
The process of claim 9, wherein the two reactants of step (b) are reacted for from 30 minutes to 2 hours.
Claim 12
Dependent Claim
9 words
The process of claim 1 wherein Y is Br.
Claim 13
Dependent Claim
34 words
The process of claim 1, wherein after the addition of the di-alkali metal tetrahalocuprate, the reaction mixture is stirred for from 2 to 3 hours at a temperture of from -70° to 0° C.
Claim 14
Dependent Claim
29 words
The process of claim 1 wherein the di-alkali metal tetrahalocuprate is used in an amount of about 0.5 to 4 mole % based on the Grignard compound IIIa employed.
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) | 1988-10-28 | 1989-04-29 | 1989-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-28 | 1993-04-29 | 1993-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-28 | 1997-04-29 | 1997-10-29 | $7700.00 | Window Closed / Lapsed |