摘要:
The present invention relates to novel intermediates for the preparation of vitamin A and carotenoids corresponding to the formula (II): ##STR1## in which A represents a hydrogen or an alkyl, alkenyl or alkoxy group containing 1 to 4 carbon atoms, and X represents a carbon atom, and to a process for their preparation and their use, and further relates to compounds for preparing intermediates of formula (II) corresponding to the formula (III): ##STR2## in which R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkylcarbonyl, alkenylcarbonyl, alkoxyalkyl or alkoxyalkenyl group in which the alkyl groups have 1 to 10 carbon atoms and the alkenyl groups have 2 to 10 carbon atoms, each of said groups being linear or branched and each being substituted or unsubstituted.
摘要:
A process for purifying vitamin A consisting of heating a vitamin A preparation in an inert atmosphere, at a temperature below 170.degree. C. and a pressure of less than 4 mm of mercury, said heating taking place in a vessel shielded from light is disclosed. The vitamin A obtained from this process is mixed with from 0.5:1 to 2:1 parts of tocopherol to vitamin A. The vitamin A and tocopherol mixture can be encapsulated in acacia gum, starch, pectins or other suitable materials. When the vitamin A is encapsulated, the level of tocopherol required is less, preferably from 0.05:1 to about 1:1 parts of tocopherol to vitamin A is used in an encapsulated vitamin A composition. Other antioxidants can be added.
摘要:
The present invention relates to a new method of condensing polyenic compounds wherein a compound having the formula III ##STR1## is condensed with a compound having the formula IV ##STR2## under the influence of a Lewis acid or a protic acid. R.sub.1 through R.sub.7 represent alkyl or alkenyl groups, A' is preferably chlorine, B is preferably a hydroxyl group, and n' is 0 to 10. The invention also relates to novel intermediates for use in the preparation of Vitamins A and E produced by means of the new method.
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:
The invention relates to compounds of formula ##STR1## having a double bond in one of the positions indicated by the dotted lines. Compounds (I) are useful as perfuming ingredients for the preparation of perfuming compositions and perfuming articles, to which they impart sandalwood-animal notes.
摘要:
The preparation of .alpha.,.beta.-unsaturated aldehydes and ketones IO.dbd.C(R.sup.1)--CR.sup.2 .dbd.CR.sup.3 R.sup.4 Iis carried out by acid hydrolysis of cyclic .alpha.,.beta.-unsaturated acetals II ##STR1## in the presence of saturated aldehydes.
摘要翻译:在饱和醛存在下,α,β-不饱和醛和酮I I = C(R 1)-CR 2 = CR 3 R 4 I的制备通过环状α,β-不饱和缩醛II II的酸水解进行。
摘要:
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.
摘要:
The invention provide a process for producing vitamin A aldehyde in high yield by oxidizing vitamin A with a aldehyde of the general formula (1) ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are the same or different and respectively represents a lower alkyl group or a lower alkenyl group in the presence of aluminum alkoxide in a catalytic amount.
摘要:
Retinal is prepared by condensing a C.sub.15 sulphide of formula: ##STR1## in which R.sub.1 denotes aryl, aralkyl, pyridyl, 2-thiazolyl, 2-benzothiazolyl, 2-benzimidazolyl or 2-benzoxazolyl, with a haloacetal of formula: ##STR2## in which X denotes a halogen atom and R denotes an alkyl radical containing 1 to 4 carbon atoms, to give a C.sub.20 sulphide acetal of formula: ##STR3## in which R.sub.1 and R are defined as above, hydrolysing the said sulphide acetal to give a C.sub.20 sulphide aldehyde of formula: ##STR4## in which R.sub.1 is defined as above, desulphurizing the said sulphide aldehyde to give retinal, and isolating the retinal obtained.
摘要:
1-[3-Methyl-3,5,5-trialkoxy-pent-1-yn-1-yl]-2,6-dimethyl-cyclohex-1-enes, which may or may not be methyl-substituted in the 2- and/or 6-position, are obtained by reacting the corresponding 1-[3-methyl-but-1-yn-3-en-1-yl]-2,6-dimethyl-cyclohex-1-enes with orthoformic acid esters in the presence of acid condensing agents. The new compounds provide a new method of access to the compounds of carotinoid chemistry, especially to vitamin A, which avoids the conventional expensive synthesis via phosphorus ylide compounds.