Patent US2300895A successfully refreshed from Google Patents.
US4968844A
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Process for preparing retinal
Assignee: Centre National de la Recherche Scientifique
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Filing: 1988-10-27
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Granted: 1990-11-06
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Expires: 2008-10-27
Abstract
Abstract Retinal is prepared by condensing a C 15 sulphide of formula: ##STR1## in which R 1 denotes aryl, aralkyl, pyridyl, 2-thiazolyl, 2-benzothiazolyl, 2-benzimidazolyl or 2-benzoxazolyl, with a haloacetal of formula: ##STR2## in which X denotes a halogen atom and R denotes an alkyl radical containing 1 to 4 carbon atoms, to give a C 20 sulphide acetal of formula: ##STR3## in which R 1 and R are defined as above, hydrolysing the said sulphide acetal to give a C 20 sulphide aldehyde of formula: ##STR4## in which R 1 is defined as above, desulphurizing the said sulphide aldehyde to give retinal, and isolating the retinal obtained.
Inventors
- 👤 Marc Julia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:53
CPC Classifications
C; C07; C07C; C07C47/00; C07C47/20; C07C403/00; C07C403/14; C07C403/22; C07B; C07B2200/00; C07B2200/09; C07C2601/00; C07C2601/12; C07C2601/16
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
126 words
Process for preparing retinal with an all trans content of about 70%, which comprises condensing a C 15 sulphide (E/Z=70:30) of the formula: ##STR12## in which R 1 denotes phenyl, benzyl, pyridyl, 2-thiazolyl, 2-benzothiazolyl, 2-benzimidazolyl or 2-benzoxazolyl, with haloacetal (E/Z=75:25) of the formula: ##STR13## in which X denotes halogen and R denotes alkyl containing 1 to 4 carbon atoms, to give a C 20 sulphide acetal of the formula: S-R 1 OR ##STR14## in which R 1 and R are defined as above, hydrolyzing the sulphide acetal to give a C 20 sulphide aldehyde of the formula: ##STR15## in which R 1 is defined as above, desulphurizing the sulphide aldehyde to give retinal with an all trans content of about 70%, and isolating the retinal obtained.
Claim 2
Dependent Claim
126 words
Process for preparing retinal with an all trans content of about 70%, which comprises condensing a C 15 sulphide (E/Z=70:30) of the formula: ##STR12## in which R 1 denotes phenyl, benzyl, pyridyl, 2-thiazolyl, 2-benzothiazolyl, 2-benzimidazolyl or 2-benzoxazolyl, with haloacetal (E/Z=75:25) of the formula: ##STR13## in which X denotes halogen and R denotes alkyl containing 1 to 4 carbon atoms, to give a C 20 sulphide acetal of the formula: S-R 1 OR ##STR14## in which R 1 and R are defined as above, hydrolyzing the sulphide acetal to give a C 20 sulphide aldehyde of the formula: ##STR15## in which R 1 is defined as above, desulphurizing the sulphide aldehyde to give retinal with an all trans content of about 70%, and isolating the retinal obtained.
Claim 3
Dependent Claim
52 words
Process according to claim 1, in which the condensation of the C 15 sulphide with the C 5 haloacetal is performed in the presence of a basic agent, with or without a second basic agent to neutralize the hydracid formed, in an organic solvent at a temperature between -100° and 100° C.
Claim 4
Dependent Claim
26 words
Process according to claim 2, in which the basic agent is an alkali metal hydroxide, alcoholate, hydride or amide or an organozinc, organolithium or organomagnesium derivative.
Claim 5
Dependent Claim
23 words
Process according to claim 2, in which the solvent is an aliphatic hydrocarbon, aromatic hydrocarbon, alcohol, ether, amide, dimethyl sulphoxide, N-methylpyrrolidone or hexamethylphosphotriamide.
Claim 6
Dependent Claim
21 words
Process according to claim 1, in which the hydrolysis of the C 20 sulphide acetal is performed in an acid medium.
Claim 7
Dependent Claim
35 words
Process according to claim 1, in which the desulphurization of the C 20 sulphide aldehyde is accomplished by means of an inorganic or organic basic agent which is an alkali metal hydroxide, carbonate or alcoholate.
Claim 8
Dependent Claim
18 words
Process according to claim 1 in which R 1 is phenyl, X is chlorine and R is methyl.
Claim 9
Dependent Claim
35 words
A C 20 sulphide acetal of formula: ##STR16## in which R 1 denotes an phenyl, benzyl, pyridyl, 2-thiazolyl, 2-benzothiazolyl, 2-benzimidazolyl or 2-benzoxazolyl radical and R denotes an alkyl radical containing 1 to 4 carbon atoms.
Claim 10
Dependent Claim
35 words
A C 20 sulphide acetal of formula: ##STR16## in which R 1 denotes an phenyl, benzyl, pyridyl, 2-thiazolyl, 2-benzothiazolyl, 2-benzimidazolyl or 2-benzoxazolyl radical and R denotes an alkyl radical containing 1 to 4 carbon atoms.
Claim 11
Dependent Claim
18 words
The C 20 sulphide acetal according to claim 8 in which R 1 phenyl and R is methyl.
Claim 12
Dependent Claim
23 words
The C 20 sulphide aldehyde of formula: ##STR17## in which R 1 denotes an phenyl, benzyl, pyridyl, 2-thiazolyl, 2-benzothiazolyl, 2-benzimidazolyl or 2-benzoxazolyl radical.
Claim 13
Dependent Claim
23 words
The C 20 sulphide aldehyde of formula: ##STR17## in which R 1 denotes an phenyl, benzyl, pyridyl, 2-thiazolyl, 2-benzothiazolyl, 2-benzimidazolyl or 2-benzoxazolyl radical.
Claim 14
Dependent Claim
15 words
The C 20 sulphide aldehyde according to claim 10 in which R 1 is phenyl.
References Cited (Backward Citations)
No citation records indexed.
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