Abstract: The invention relates to a process for preparing chiral imidazolidin-2-ones of the formula I in which R1 is C1-C8-alkyl, cyclohexyl, phenyl, a C1-C6-alkyl-, halo-, nitro-, C1-C6-alkoxy-, C1-C6-alkylmercapto- or CF3-substituted phenyl radical, naphthyl or a C1-C6-alkyl-, halo-, nitro-, C1-C6-alkoxy- or CF3-substituted naphthyl radical, R2 is C1-C8-alkyl, C2-C8-alkenyl, cyclohexyl, phenyl or a phenyl-C1-C6-alkyl radical which may be substituted by a nitro, C1-C6-alkoxy, methylenedioxy or CF3 radical, and R3 is C1-C12-alkyl, C2-C8-alkenyl, cyclohexyl, phenyl or a C1-C6-alkyl-, halo-, nitro-, C1-C6-alkoxy-, methylenedioxy-, dialkylamino- or CF3-substituted phenyl radical, by reacting a compound of the formula II or the salt thereof in which R1, R2 and R3 have the abovementioned meaning, with urea in the presence of an involatile ammonium salt, wherein the reaction is carried out in the presence of an aprotic polar 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 present invention relates to a practical and cost-effective method for the synthesis of 5-chloromethylated 2,3-dialkoxy-6-alkyl-1,4-benzoquinones by direct chloromethylation of the corresponding 2,3-dialkoxy-6-alkyl-1,4-benzoquinones. The invention further relates to a method for the preparation of 5-chloromethylated 2,3-dialkoxy-6-alkyl-1,4-benzoquinones starting from a 3,4,5-trialkoxy-1-alkyl-benzene. The invention also relates to a method for the production of Coenzymes Qn, especially coenzyme Q10.

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: The invention relates to a process for preparing chiral imidazolidin-2-ones of the formula I in which R1 is C1-C8-alkyl, cyclohexyl, phenyl, a C1-C6-alkyl-, halo-, nitro-, C1-C6-alkoxy-, C1-C6-alkylmercapto- or CF3-substituted phenyl radical, naphthyl or a C1-C6-alkyl-, halo-, nitro-, C1-C6-alkoxy- or CF3-substituted naphthyl radical, R2 is C1-C8-alkyl, C2-C8-alkenyl, cyclohexyl, phenyl or a phenyl-C1-C6-alkyl radical which may be substituted by a nitro, C1-C6-alkoxy, methylenedioxy or CF3 radical, and R3 is C1-C12-alkyl, C2-C8-alkenyl, cyclohexyl, phenyl or a C1-C6-alkyl-, halo-, nitro-, C1-C6-alkoxy-, methylenedioxy-, dialkylamino- or CF3-substituted phenyl radical, by reacting a compound of the formula II or the salt thereof in which R1, R2 and R3 have the abovementioned meaning, with urea in the presence of an involatile ammonium salt, wherein the reaction is carried out in the presence of an aprotic polar organic solvent.

Abstract: The invention relates to a method for producing compounds of general formula (I), wherein Rt represents an oxocyclohexyl radical which is optionally substituted by a hydroxyl radical, an alkoxy radical, and/or alkyl radicals, or an oxocyclohexenyl radical which is optionally substituted by a hydroxyl radical, an alkoxy radical, and/or alkyl radicals, the oxo groups being in the form of an acetal, a ketone, or an enol ether, and R2 represents a hydroxy group or a protective group which can be transformed into a hydroxy group by means of hydrolysis. A compound of general formula (II) is cathodically reduced in a divided or partially divided electrolysis cell at a pH value of between 2 and 9.

Abstract: The invention relates to a process for the preparation of cis-6-hexadecenoic acid of the formula I, which comprises reacting a1) a triphenylphosphonium salt of the formula II, R1OOC—(CH2)5—P(R2)3+X−  II  with decanal of the formula III H3C—(CH2)8—CH═O  III  or a2) a triphenylphosphonium salt of the formula IV, H3C—(CH2)9—P(R2)3+X−  IV  with an aldehyde of the formula V, R1OOC—(CH2)4—CH═O  V  in a Wittig reaction, and b) saponifying the ester, formed by process step a1) or a2), of the formula VI,  where the substituents R1, R2 and X− have the meanings given in the description.

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 preparing N-acyl derivatives of the formula I, in which the substituents independently of one another have the following meanings: X is CH(OR3)2, COOR3; R1 is hydrogen, C1-C12-alkyl, aryl, unsubstituted or substituted; R2 is hydrogen, C1-C12-alkyl, aryl, unsubstituted or substituted; R3 is C1-C12-alkyl, which comprises reacting a carboxamide R1—CONH2 of the formula II with a glyoxal monoacetal derivative of the formula III, in the presence of a carboxylic acid R4—COOH of the formula IV where R4=C1-C12-alkyl, where the substituents R1 to R3 are as defined above, is described.

Abstract: A process is provided for the preparation of cyclohexene derivatives of general formula I or II: in which the substituents R1 and R2 independently of one another are defined as follows: R1 is R2 is OH or a protective group convertible to a hydroxyl group by hydrolysis; R3 and R4 are hydrogen or C1-C4-alkyl; and R5 is hydrogen or C1-C4-acyl, by the reduction of alkyne compounds of general formula III or IV: in which the substituents R1 and X are as defined above, wherein the reducing agent used is a mixture of zinc and at least one compound B selected from the group consisting of ammonium salts, copper salts and alkali metal and alkaline earth metal salts.

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

Abstract: A process for the preparation of 1,1,4,4-tetramethoxy-2-butene by reacting 2,5-dimethoxydihydrofuran with methanol in the presence of acids comprises carrying out the reaction in the presence of solid catalysts having acidic centers.

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