摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
Sulphones of formula QSO.sub.2 CH.sub.2 CY=CY.sub.1 CH.sub.2 CHRR.sub.1 wherein one of Y and Y.sub.1 is hydrogen the other methyl, R and R.sub.1 are CHO, COR.sub.2, COOH, COOR.sub.3, CONR.sub.5 R.sub.5, CN, SO.sub.2 R.sub.4, SO.sub.3 R.sub.5 and NO.sub.2, wherein R.sub.2 -R.sub.5 are alkyl or aryl and R.sub.5 can be hydrogen, and Q is alkyl, substituted alkyl, aryl, aralkyl or alkaryl or optionally substituted, optionally unsaturated terpene of 5n carbon atoms (n being 1-9), but excluding 2- or 3-methylbutadienyl and 2-butadienylmethyl, are intermediates for preparing terpenes.
摘要:
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.
摘要:
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.