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US 2002/0026082 A1Published application
Process for preparing 2,7-dimethyl-2,4,6-octatriene-1,8-dial
AssigneeSangho Koo
InventorsSangho Koo, Hojin Choi, Minsoo Park, Minkoo Ji
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Abstract
Intermediates useful in the synthesis of a compound having polyene chain structure, processes for preparing the same, and a process for preparing β-carotene utilizing the same are disclosed. Also disclosed is a novel compound, retinyl sulfide, which was synthesized by the coupling of a diallylic sulfide of the present invention with the corresponding Wittig salt.
Claims11
A diallylic sulfide compound represented by Formula 1
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- wherein:
- R1 and R2 are independently chosen from the group consisting of —CHO, —CH2Cl, —CH2Br, —CH2I, —CH2OH, CH2OSO2CF3, —CH2OSO2Ph, —CH2OSO2C6H4CH3 and —CH2OSO2CH3.
A process for preparing 2,7-dimethyl-2,4,6-octatriene-1,8-dial, represented by Formula 2
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- which comprises the steps of:
- (a) providing an allylic halide of Formula (A)
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- wherein X is chosen from Br, Cl and I;
- (b) protecting the aldehyde of the allylic halide to obtain an acetal of Formula G
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- wherein R3 and R4 are independently chosen from —H and —CH3;
- (c) reacting the acetal of step (b) with sodium sulfide to obtain di(3-formyl-3-methyl-2-propenyl)sulfide, dialkyl diacetal of Formula H;
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- (d) oxidizing the product of step (c) to obtain an allylic sulfone of Formula I;
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- (e) subjecting the allylic sulfone of step (d) to a Ramberg-Bäcklund reaction to obtain a triene of Formula J;
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- (f) hydrolyzing the triene of step (e) to obtain a compound of Formula 2.
12 more elements
A process for preparing β-carotene, represented by Formula 3
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- which comprises the steps of:
- (a) providing a sulfone compound of Formula B
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- (b) deprotonating the sulfone compound of Formula B and reacting not more than ½ equivalent, based upon the sulfone compound, of an allylic sulfide, represented by Formula C
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- wherein X is a halogen, to provide a sulfide compound of Formula D
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- (c) oxidizing the sulfide compound of step (b) to provide a sulfone compound of Formula E
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- (d) subjecting the sulfone compound of step (c) to a Ramberg-Bäcklund reaction to provide 11,20-dibenzenesulfonyl)-11,12,19,20 tetrahydro-β-carotene of Formula F
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- (e) reacting the product of step (d) with a base to obtain β-carotene of Formula 3.
10 more elements
A compound represented by Formula 4
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Dependencies are inferred from the claim text.