摘要:
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, β-carotene, zeaxanthin, canthaxanthin, astaxathin, lycopene and croceptin, which are useful as nutraceuticals, food colorants, and feed additives.
摘要:
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.
摘要:
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.
摘要:
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.
摘要翻译:本发明涉及一种制备通式Ⅰ的2,7-二甲基-2,4,6-辛二烯一缩醛的方法,它包括:a)将通式Ⅱ的酯鏻盐或通式Ⅲ的酯膦酸酯与醛 的维t希或维蒂希 - 霍纳反应,得到通式Ⅴb的缩醛Vb)of of of V V the the the the the--------c c c c c c c c c c c c c 具有通式I的2,4,6-八碳三烯单缩醛,其中取代基具有在说明书中定义的含义。