Abstract: A method for determining the operating state of a light-emitting implant implanted in the brain of a living being, the light-emitting implant including a light source responsible for emitting light into the brain of the living being, the method using a diagnosing device that includes a receiver of a light signal transmitted through a first eye of the living being and a device for determining the operating state of the light-emitting implant based on the received transmitted light signal.

Abstract: The present invention relates to a process for the preparation of terpenic ketones, which comprises reacting a 1,3-butadiene derivative with a .beta.-keto ester followed by decarbalkoxylation of the product.

Abstract: A process for the preparation of vitamin A which preferably comprises bringing cyclogeranyl sulphone into contact with a C.sub.10 aldehyde acetal, halogenating the derivative obtained and then removing the halogen group and the sulphone, removing the acetal group and isomerizing the retinal obtained to the desired configuration. Also disclosed are compounds useful as intermediates in the synthesis of vitamin A and processes for preparation of these intermediate compounds.

Abstract: A process for the preparation of vitamin A which preferably comprises bringing cyclogeranyl sulphone into contact with a C.sub.10 aldehyde acetal, halogenating the derivative obtained and then removing the halogen group and the sulphone, removing the acetal group and isomerizing the retinal obtained to the desired configuration. Also disclosed are compounds useful as intermediates in the synthesis of vitamin A and processes for preparation of these intermediate compounds.

Abstract: The present invention relates to a process for preparing halo acetals of ethylenic aldehydes by reaction of a halogen cation with enamine followed by a hydrolysis and reaction with an alcohol, a glycol or an orthoformate. These halo acetals are used as intermediate for the synthesis of vitamins A and E.It also relates to a new compound of formula (IV), ##STR1## to a process for preparing it from halo acetals of ethylenic aldehydes by reaction with triethyl phosphate, and to its use for the preparation of retinal by reaction with .beta.-ionylideneacetaldehyde.

Abstract: A process for the purification of pseudo-ionone, which comprises preparing pseudo-ionone by a reaction of citral with acetone, followed by bringing the reaction medium into contact with a metal derivative and thereafter distilling the pseudo-ionone.

Abstract: The invention relates to a process for preparing unsaturated aldehydes and their enamines by the oxidation of allylic tertiary amines in the presence of an alkyl hydroperoxide and a vanadium-based catalyst.

Abstract: An improved method for preparing citral in liquid phase from prenol and prenal, wherein, in a single reaction enclosure, the prenol and prenal are condensed in the presence of a mineral acid at a concentration of about 5.10.sup.-3 mole for one mole of prenal, 90 to 95% of the acid is neutralized, and once excess prenal and prenol is eliminated, the citral is distilled.

Abstract: A process for preparing cyclocitral by expoxidizing a pyronene.

Abstract: Epoxides represented by the formula: ##STR1## in which A represents a methylene or oxirane group and a process for their preparation.

Abstract: A process for converting tertiary amine N-oxides to aldehydes by reacting tertiary amine N-oxides in the presence of a catalytic quantity of a vanadium containing compound.

Abstract: The present invention relates to a process for preparing halo acetals of ethylenic aldehydes by reaction of a halogen cation with enamine followed by a hydrolysis and reaction with an alcohol, a glycol or an orthoformate. These halo acetals are used as intermediate for the synthesis of vitamins A and E.It also relates to a new compound of formula (IV), ##STR1## to a process for preparing it from halo acetals of ethylenic aldehydes by reaction with triethyl phosphate, and to its use for the preparation of retinal by reaction with .beta.-ionylideneacetaldehyde.

Abstract: Citral is prepared from prenol and prenal by condensation to form an acetal followed by cracking, both operations being effected in the presence of a lithium halide (e.g. lithium chloride) as catalyst.

Abstract: Ethylenic carbonyl compounds of formula ##STR1## are made by the isomerization of acetylenic alcohols of formula ##STR2## in the presence of a catalyst consisting of a titanium derivative, a copper or silver derivative, and, if required, an acid, which may be in the form of an ester or anhydride, or an inorganic ester.

Abstract: Hexadecene derivatives of the formulae: ##STR1## and ##STR2## in which X and X.sub.1, which may be identical or different, each represent hydrogen or chlorine, and their mixtures, are useful in the preparation of tocopherol and tocopherol acetate.

Abstract: Tocopherol derivatives of the formula: ##STR1## in which X and X.sub.1, which may be identical or different, each represent hydrogen or chlorine and their acetates are useful in the synthesis of vitamin E.

Abstract: Process for preparing chlorinated ethylenic derivatives of the formula ##STR1## in which R.sub.1 represents acetyl, formyl optionally in the form of an acetal, hydroxy optionally as an ether or ester, alkyloxycarbonyl, alkyl of 1 to 12 carbon atoms substituted by one or more acetyl, formyl optionally in the form of an acetal, hydroxy optionally in the form of an ether or ester, or alkyloxycarbonyl, alkenyl of 2 to 12 carbon atoms containing one or more double bonds optionally substituted by one or more of acetyl, formyl optionally in the form of an acetal, hydroxy optionally in the form of an ether or ester, or alkyloxycarbonyl, or R.sub.1 represents 3-sulpholenyl or a radical of formula ##STR2## in which R.sub.2 denotes a hydrogen or acetyl, by reacting chlorine in a nonpolar aprotic solvent with a compound of general formula ##STR3## in which R.sub.1 is defined as above. The products of formula I, some of which are new, are useful as intermediates in the synthesis of terpene products such as vitamin E.

Abstract: 1,5-Dimethyl-hexa-1,5-dienylene compounds, and especially Vitamin A and derivatives thereof, are made by desuphonylating with a basic reagent a sulphone of the formula: ##STR1## in which the sulphonyl group --SO.sub.2 R replaces a hydrogen atom on carbon atom (a) or (b), R represents a phenyl or napthyl group, A is 2-(2,6,6-trimethylcyclohex-1-enyl)ethenyl, and Q is --CH.sub.2 OH or an ether or ester thereof, CHO, or an acetal group.

Abstract: Citral is prepared by heating dehydrolinalol in the presence of a vanadium compound as catalyst and an alkanol of 12 to 18 carbon atoms as co-catalyst, whereby isomerization is effected. There may also be present an alkanol or cycloalkanol of 7 to 11 carbon atoms as co-catalyst.

Abstract: Sulphones useful for preparing polyenes have the formula: ##STR1## where the sulphonyl group replaces a hydrogen atom on carbon atom (a) or (b), R represents alkyl, aralkyl or aryl, optionally substituted, A and Q represent an optionally substituted hydrocarbon of 5n+1 carbon atoms (n is 1-5), methyl, optionally substituted by halogen, sulphide or sulphone, CH.sub.2 OH (or an ether or ester thereof), CHO (optionally protected), COOH (or an acid chloride, ester or nitrile thereof), with the proviso that when A represents a 2-(2,6,6-trimethylcyclohex-1-enyl) ethenyl radical, Q cannot represent --COOH or an ester thereof.