- Sulphur-containing eicosanoides and their application in pharmacy and in cosmetics
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Compounds corresponding to the formula: STR1 wherein A represents --CH2)2 or --C C--; n is equal to 0, 1 or 2; R represents hydroxyl, alkoxy having the formula --OR1, or amino having the formula STR2 R1 represents alkyl, monohydroxyalkyl, polyhydroxyalkyl, aryl or aralkyl; R2 and R3 represent hydrogen, alkyl, monohydroxyalkyl, polyhydroxyalkyl, aryl or benzyl; R2 and R3 form, with the nitrogen atom, a heterocyclic ring. Application of these compounds in pharmacy and cosmetics.
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- Alkynyl halide compounds and alkenyl acetate compounds therefrom
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The invention provides a novel method for the synthetic preparation of an ω-haloalkyne compound of the general formula R--C C--CH2)n X, in which X is a halogen atom, R is a monovalent hydrocarbon group and n is 4, 5 or 6, by the coupling reaction of a Grignard reagent RMgX' and an ω-halo-1-bromoalkyne compound of the formula X--CH2)n C C-Br. The ω-haloalkyne compound obtained in the above can be readily converted to the corresponding alkenyl acetate of the formula R--CH=CH--CH2)n OCOCH3 by first acetylating and then partially hydrogenating in the presence of a Lindlar catalyst. In particular, 7, 11-hexadecadienyl acetate, which is a sexual pheromone compound of a noxious insect, is obtained in the same route of synthesis starting with the Grignard reagent of a 1-halo-3-octene and 1, 8-dibromo-1-octyne.
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- Coupling reaction involving a Grignard and allylic halide
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Disclosed is a process for the coupling of a Grignard reagent RMgX with an allylic halide in the presence of a dipolar aprotic solvent wherein the improvement, for obtaining improved yield and selectivity, comprises adding a catalyst to said Grignard or allylic halide and then carrying out the coupling reaction by the addition of the Grignard reagent to the allylic halide, said reaction being characterized by the displacement at the gamma position (relative to the halide) of the allylic halide with R of the Grignard reagent, migration of the allylic double bond in the direction of the halogen atom and loss of halogen. The present invention also resides in the discovery of certain novel procedures for the synthesis of Vitamin E. Specific embodiments of this aspect of the invention reside in the syntheses of 6,7-dehydrophytol, 10,11-dihydrofarnesene, phytone, hexahydropseudoionone, and related compounds as precursors for Vitamin E.
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- Unsaturated vitamin E intermediates--dehydro and didehydro α-tocopherols
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New dehydrotocopherols, namely cis- and trans- 3',4'-dehydrotocopherol; cis- and trans- 4',5'-dehydrotocopherol; and 4',4'-a-dehydrotocopherol, and new didehydrotocopherols, namely cis- and trans- 3',4'-11',12'-didehydrotocopherol; cis- and trans- 4',5'-11',12'-didehydrotocopherol; and 4',4'a-11',12'-didehydrotocopherol, are useful intermediates in the preparation of Vitamin E. These intermediates are prepared by reacting trimethylhydroquinone under acid catalysis with certain C20 intermediates, namely: STR1 where R represnts a 3,7-dimethyloctyl or a 3,7-dimethyl-6-octenyl radical and X is halogen, hydroxyl, acetate, C1-4 alkanoate, C3-4 alkenoate, aralkenoate and benzoate.
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