Abstract: The present invention relates to new fluorinated hexane compounds corresponding to the following general formula (II): ##STR1## in which X'.sub.2, X'.sub.3, and X'.sub.4 are the same or different, and denote a halogen or a pseudohalogen, preferably a halogen, more preferably chlorine and fluorine, with the condition that, when R.sub.1 is hydroxyl, cyano, amido, imido, ethoxy, benzyloxy, cyclohexyloxy and tert-butoxy, not all the halogens can simultaneously be chlorine and R.sub.4, R.sub.3 and R.sub.5 are simultaneously equal to H;R.sub.1 denotes a hydrogen, a hydrocarbon chain such as an alkyl chain, alkoxy, cycloalkyl ether, an aromatic group, aromatic ether or an alkoxy, carbonyl, carboxyl or acyloxy, cyano, amido, imido or hydroxyl group;R.sub.

Abstract: The present invention relates to new fluorinated hexane compounds corresponding to the following general formula (II): ##STR1## in which X'.sub.2, X'.sub.3 and X'.sub.4 are the same or different, and denote a halogen or a pseudohalogen, preferably a halogen, more preferably chlorine and fluorine, with the condition that, when R.sub.1 is hydroxyl, cyano, amido, imido, ethoxy, benzyloxy, cyclohexyloxy and tert-butoxy, not all the halogens can simultaneously be chlorine and R.sub.4, R.sub.3 and R.sub.5 are simultaneously equal to H;R.sub.1 denotes a hydrogen, a hydrocarbon chain such as an alkyl chain, alkoxy, cycloalkyl ether, an aromatic group, aromatic ether or an alkoxy, carbonyl, carboxyl or acyloxy, cyano, amido, imido or hydroxyl group;R.sub.

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: New intermediates and processes for the preparation of vitamins A and E, which are the acetals of 5,6-dihalo-3-methyl-3-hydroxyhexanal or of 6-halo-3-hydroxy-3-methyl-5-hexenal or 3-methyl-3-hydroxy-5-hexenal, as well as processes for making the intermediates. After dehydrohalogenation and dehydration these intermediates are condensed directly with .beta.-ionone or with 2-methyl-2-heptene-6-one to synthesize vitamins A and E respectively.

Abstract: The present invention relates to dihydropyran derivatives, processes for preparing, and processes of using the derivatives. The derivatives are prepared by condensation of lithium dienolate of prenal with an aldehyde or a ketone.The pyran derivative prepared from .beta.-ionylideneacetaldehyde when treated in the presence of a catalyst directly forms retinal.

Abstract: The present invention relates to dihydropyran derivatives, processes for preparing, and processes of using the derivatives. The derivatives are prepared by condensation of lithium dienolate of prenal with an aldehyde or a ketone.The pyran derivative prepared from .beta.-ionylideneacetaldehyde when treated in the presence of a catalyst directly forms retinal.

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: New intermediates and processes for the preparation of vitamins A and E, which are the acetals of 5,6-dihalo-3-methyl-3-hydroxyhexanal or of 6-halo-3-hydroxy-3-methyl-5-hexenal or 3-methyl-3-hydroxy-5-hexenal, as well as processes for making the intermediates. After dehydrohalogenation and dehydration these intermediates are condensed directly with .beta.-ionone or with 2-methyl-2-heptene-6-one to synthesize vitamins A and E respectively.

Abstract: The invention relates to the preparation of alkylthiophenols by reaction of a dialkyl disulphide with a phenol.In the process according to the invention, the reaction is carried out in the presence of aluminum chloride or of ferric chloride in a solvent of the alkylbenzene type or, soley in the case of methylthiolation, in an excess of dimethyl disulphide.This process makes it possible, in particular to obtain, with a selectivity and in a yield which are excellent, 2-alkylthiophenols which may then be converted into 4-acyl-2-alkylthiophenols by means of a reaction at a temperature ranging from 40.degree. to 100.degree. C. with a complex BF.sub.3 :2RCOOH where R denotes an alkyl or propenyl radical, in a proportion of 10 to 15 moles of complex per mole of 2-alkylthiophenol.