Basf Aktiengesellschaft

Michael John

Joachim Paust

Christoph Wegner

Walter Dobler

Wolfgang Siegel

Hagen Jaedicke

Udo Rheude

Joachim Meyer

J&ouml;rg Botzem

The present invention relates to a process for the thermal isomerization of a mixture of all-E-lycopene and its Z isomers of any composition to increase the proportion of all-E, wherein the isomerization takes place in a polar solvent in which lycopene is only slightly soluble.

Thermal isomerization of lycopene

Phosphonium salts are prepared by reacting an alkanol with triarylphosphine and sulfonic acids in a solvent.

Preparation of phosphonium salts

Process for preparing phosphonium salts

Process for preparing folic acid

Phosphonium salts are prepared by reacting an alkanol with triarylphosphine and alkyl or trifluoromethane sulfonic acids in a solvent.

A process for preparing 4-hydroxy-1,2,2-trimethylcyclopentyl methyl ketones of the general formula I, in particular of the (1R,4S)-4-hydroxy-1,2,2-trimethylcyclopentyl methyl ketone of the formula Ia ##STR1## which is required for preparing the red dye capsorubin which is in demand, starts from 2,2,6-trimethylcyclohexanones of the general formula II ##STR2## where R is hydrogen or a protective group, via the novel intermediates of the general formulae V and VI ##STR3## by diastereoselective epoxidation and reaction of the resulting 7-oxabicyclo[4.1.0]heptanes of the general formula VIII ##STR4## with Lewis acids and, where appropriate, removal of the protective group. Also claimed are the novel intermediates of the formula V and their (1S) and (1R) isomers and those of the formula VIII as well as their (1R,3S,6S), (1S,3S,6R) and (1R,3R,6S) isomers.

Preparation of (1R,4S)-4-hydroxy-1,2,2-trimethylcyclopentyl methyl

A process for preparing .alpha.-chloroalkyl aryl ketones of the formula I ##STR1## where n is 1 to 5,

Preparation of .alpha.-chloroalkyl aryl ketones

.beta.-Carotene products with a high proportion of the 9(Z) isomer are prepared starting from mother liquors from the industrial preparation of .beta.-ionylideneethyltriarylphosphonium salts (C.sub.15 -triarylphosphonium salts) by Wittig reaction of a C.sub.15 -triarylphosphonium salt which has been enriched in the 9Z isomer directly with .beta.-apo-12'-carotenal or else with 2,7-dimethyl-2,4,6-octatrienedial and subsequently with the C.sub.15 -triarylphosphonium salt and subsequent thermal isomerization.

Preparation of .beta.-carotene products with a high 9 (Z) content

5-Hydroxy-4-methyl-2(5H)-furanone is prepared by cyclization of alkyl .beta.-formylcrotonates by heating with dilute aqueous hydrochloric acid or, advantageously, in the presence of dilute aqueous hydrochloric acid and catalytic amounts of methanol as solubilizer, subsequent workup of the reaction mixture by distillation and, where appropriate, isomerization of the 5-methoxy- or 5-ethoxy-4-methyl-2(5H)-furanone, which is formed as byproduct, by heating with dilute hydrochloric acid.

Preparation of 5-hydroxy-4-methyl-2(5H)-furanone

A process for preparing 9-(Z)-retinoic acid from mother liquors from the industrial preparation of C.sub.15 -triarylphosphonium salts of the general formula I ##STR1## where R.sup.1 to R.sup.3 are each aryl and X.sup..crclbar. is halogen or (HSO.sub.4).sup..crclbar., in an organic solvent, which comprises

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Lambsheim, Germany

Michael John