Abstract: The present invention relates to an improved method for producing all-E astaxanthin dimethyldisuccinate of the formula I.

Abstract: The present invention relates to an improved method for producing all-E astaxanthin dimethyldisuccinate of the formula I.

Abstract: A process for preparing carotenoids, in which the process includes reacting a dialkoxy dialdehyde in a double Wittig condensation with a phosphonium salt of or in a double Wittig-Horner condensation with a phosphonate. The carotenoids include, for example, ?-carotene, zeaxanthin, canthaxanthin, astaxathin, lycopene and croceptin, which are useful as nutraceuticals, food colorants, and feed additives.

Abstract: The present invention relates to an improved process for preparing 2,7-dimethylocta-2,4,6-trienedial of the formula I, by a) double enol ether condensation of a butenedial bisacetal of the formula II with an enol ether of the formula III, ?in the presence of a Lewis acid catalyst to give a condensation product of the formula IV, ?where the radicals R1 and R2 in formulae II to IV are independently of one another C1-C6-alkyl; b) hydrolysis of the acetal groups of IV by adding an aqueous acid to form the dialdehyde of the formula V; d) crystallization of I from the reaction mixture, Wherein process steps a) to d) are carried out in the presence of an inert, water-immiscible organic solvent.

Abstract: The present invention relates to an improved process for preparing 2,7-dimethylocta-2,4,6-trienedial of the formula I, by a) double enol ether condensation of a butenedial bisacetal of the formula II with an enol ether of the formula III, ?in the presence of a Lewis acid catalyst to give a condensation product of the formula IV, ?where the radicals R1 and R2 in formulae II to IV are independently of one another C1-C6-alkyl; b) hydrolysis of the acetal groups of IV by adding an aqueous acid to form the dialdehyde of the formula V; d) crystallization of I from the reaction mixture, Wherein process steps a) to d) are carried out in the presence of an inert, water-immiscible organic solvent.

Abstract: The invention relates to a process for preparing phytofluene of the formula I, where a) a phosphonium salt of the formula II is condensed with an aldehyde of the formula III in a Wittig reaction to give an acetal of the formula IV b) the condensation product of the formula IV is subjected to an acid-catalyzed acetal hydrolysis to give the aldehyde of the formula V c) and V is condensed in a further Wittig reaction with a phosphonium salt of the formula VI to give phytofluene where the radicals R1, R2 and R7, and X? and Y? have the meaning sated in the description.

Abstract: The invention relates to a process for preparing phytofluene of the formula I, where a) a phosphonium salt of the formula II is condensed with an aldehyde of the formula III ?in a Wittig reaction to give an acetal of the formula IV b) the condensation product of the formula IV is subjected to an acid-catalyzed acetal hydrolysis to give the aldehyde of the formula V c) and V is condensed in a further Wittig reaction with a phosphonium salt of the formula VI to give phytofluene ?where the radicals R1, R2 and R7, and X? and Y? have the meaning sated in the description.

Abstract: A process for preparing carotenoids, in which the process includes reacting a dialkoxy dialdehyde in a double Wittig condensation with a phosphonium salt of or in a double Wittig-Horner condensation with a phosphonate. The carotenoids include, for example, ?-carotene, zeaxanthin, canthaxanthin, astaxathin, lycopene and croceptin, which are useful as nutraceuticals, food colorants, and feed additives.

Abstract: A process for preparing compounds of the formula I is described and entails converting a compound of the formula II by Wittig or Wittig-Horner reaction into a compound of the formula IV, where appropriate converting the compound of the formula IV by hydrolysis of the acetal function and Wittig or Wittig-Horner reaction into a compound of the formula VI and converting the compound of the formula IV or VI in two stages into the compound of the formula I. The radicals R1, R2 and R6 and k have the meaning indicated in the description. Novel intermediates are also described.

Abstract: A process for the preparation of optically pure acetylenediols of the formulae R-I and S-I and their further reaction to give meso-zeaxanthin are described.

Abstract: A process for the preparation of optically pure acetylenediols of the formulae R-I and S-I and their further reaction to give meso-zeaxanthin are described.

Abstract: A process for the preparation of optically pure acetylenediols of the formulae R-I and S-I 1

Abstract: The invention relates to a process for preparing 2,7-dimethyl-2,4,6-octatrienal monoacetals of the general formula I which comprises a) condensing an ester phosphonium salt of the general formula II or an ester phosphonate of the general formula III with an aldehyde of the formula IV in a Wittig or Wittig-Horner reaction to give an acetal ester of the general formula V b) reducing the ester of the formula V to give an acetal alcohol of the general formula VI and c) oxidizing the alcohol to 2,7-dimethyl-2,4,6-octatrienal monoacetals of the general formula I, where the substituents have the meaning defined in the description.

Abstract: A process for preparing compounds of the formula I 1

Abstract: A process for the preparation of optically pure acetylenediols of the formulae R-I and S-I 1

Abstract: The invention relates to a process for preparing 2,7-dimethyl-2,4,6-octatrienal monoacetals of the general formula I 1

Abstract: Improved process for the preparation of astaxanthin by Wittig reaction of 2 mol of 3-methyl-5-(2,6,6-trimethyl-3-oxo-4-hydroxy-1-cyclohexenyl)-2,4-pentadieny ltriarylphosphonium salts with one mol of 2,7-dimethyl-2,4,6-octatrienedial avoiding the use of halohydrocarbons as solvents.