摘要:
.omega.,.omega.-Diacyloxy-2,6-dimethyl-octatrienoates and -octatrienals, as novel bifunctional asymmetric C.sub.10 building blocks for terpene syntheses, which possess a formyl or alkoxycarbonyl group at one chain end and 2 geminal acyloxy groups at the other, and a process for their preparation from readily obtainable industrial C.sub.5 building blocks and their use for the synthesis of terpene compounds by carbonyl olefination under conventional conditions.
摘要:
2-Alkyl-4,4-diacyloxybut-2-enals of the formula ##STR1## where R.sup.1 is alkyl and R.sup.2 and R.sup.3 are each hydrogen or an aliphatic, cycloaliphatic or aromatic radical, are prepared by a process in which a 2-alkyl-1,4-diacyloxybuta-1,3-diene of the formula ##STR2## is reacted with oxygen or an oxygen donor, in the presence of a carboxylic acid of the formulaR.sup.3 -COOH III.
摘要:
2-alkyl-4,4-diacyloxybut-2-enals of the formula ##STR1## where R.sup.1 is alkyl and R.sup.2 and R.sup.3 are each hydrogen or an aliphatic, cycloaliphatic or aromatic radical, are prepared by a process wherein a 2-alkyl-2,4-diacyloxybut-3-enal of the formula ##STR2## is treated with an aliphatic carboxylic acid.
摘要:
2-Alkyl-2,4-diacyloxy-but-3-enals of the formula ##STR1## where R.sup.1 is alkyl and R.sup.2 is hydrogen, alkyl, a cycloaliphatic radical or an aromatic radical, are prepared by reacting a buta-1,3-diene of the formula ##STR2## with an oxygen donor. The new compounds are valuable intermediates in the preparation of terpenes, e.g. retinal, .beta.-carotin and apocarotinoids.
摘要:
Substituted hexatriene derivatives of the formula I ##STR1## where R.sup.1 has the meaning given in the description, and their preparation, are described. The compounds may be used to treat acne and psoriasis.
摘要:
2-Alkyl-4,4-diacyloxybut-2-enals of the formula ##STR1## where R.sup.1 is alkyl and R.sup.2 is hydrogen or an aliphatic, cycloaliphatic or aromatic radical, are prepared by a process in which a 2-alkyl-1,4-diacyloxy-1,3-butadiene of the formula ##STR2## is reacted with oxygen or an oxygen donor in the presence of an acidic ion exchanger.
摘要:
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-pentadienyltriarylphosphonium salts with one mol of 2,7-dimethyl-2,4,6-octatrienedial avoiding the use of halohydrocarbons as solvents.
摘要:
(6S)-6,8-Dihydroxyoctanoic esters I ##STR1## (R.sup.1 =alkyl, cycloalkyl, aralkyl or aryl), are prepared by reducing a (3S)-3-hydroxyoctanedioic diester II ##STR2## (R.sup.2 =an R.sup.1 radical group) with a complex hydride and are mainly used as intermediates for synthesizing compounds of the type of liponic acid.
摘要翻译:通过还原(3S)-3-羟基辛二酸二酯II(R 2 = R 1)制备(6S)-6,8-二羟基辛酸酯I(R1 =烷基,环烷基,芳烷基或芳基) 自由基基团),并且主要用作合成脂肪酸类化合物的中间体。
摘要:
An improved process for preparing cyclic acetals of 3-formyl-2-butenyltriphenylphosphonium chloride by acetalization of 3-formyl-2-butenyl acetate with an aliphatic 1,3-diol, conversion of the resulting 4-acetoxy acetal into the corresponding 4-hydroxy acetal, Vilsmeier chlorination to give the corresponding 4-chloro acetal and subsequent reaction with triphenylphosphine entails carrying out the first 3 steps in an aliphatic or cycloaliphatic hydrocarbon or mixture of hydrocarbons with 6-8 carbons and the reaction with triphenylphosphine in an alkanol with 1-3 carbons and/or in aliphatic or cycloaliphatic hydrocarbon with 6-8 carbons or a corresponding mixture of hydrocarbons. The process is particularly advantageous when conversion of the 4-acetoxy acetal into the 4-hydroxy acetal is carried out with an aqueous alkali metal hydroxide solution in the presence of phase-transfer catalysts, and the first three, or all four, reaction stages are carried out in the same C.sub.6 -C.sub.8 -hydrocarbon.
摘要:
A process for the preparation of .beta.-hydroxycarboxylates of the general formula I ##STR1## in which R.sup.1 and R.sup.2 individually denoteC.sub.1 -C.sub.20 alkyl optionally substituted by C.sub.1 -C.sub.8 alkoxy and/or halogen, C.sub.3 -C.sub.20 alkoxycarbonylalkyl, C.sub.2 -C.sub.20 alkenyl, C.sub.5 -C.sub.30 acetalalkenyl, aryl optionally mono- to penta-substituted by C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, and/or halogen, C.sub.7 -C.sub.20 aralkyl, C.sub.7 -C.sub.20 aralkenyl, hetaryl, C.sub.3 -C.sub.20 cycloalkyl, or C.sub.4 -C.sub.20 cycloalkylalkyl,or together denote a C.sub.2 -C.sub.8 alkylene chainand one or other of R.sup.1 and R.sup.2 denotes hydrogen, andR.sup.3 denotes hydrogen, C.sub.1 -C.sub.20 alkyl, C.sub.2 -C.sub.20 alkenyl, aryl optionally mono- to penta-substituted by C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, and/or halogen, C.sub.7 -C.sub.20 aralkyl, C.sub.3 -C.sub.20 cycloalkyl, or C.sub.4 -C.sub.20 cycloalkylalkyl, andR.sup.4 denotes C.sub.1 -C.sub.20 alkyl, C.sub.4 -C.sub.20 alkenyl, C.sub.7 -C.sub.20 aralkyl, C.sub.3 -C.sub.20 cycloalkyl, or C.sub.4 -C.sub.20 cycloalkylalkyl,by the reaction of carbonyl compounds of the general formula II ##STR2## in which R.sup.1 and R.sup.2 have the meanings stated above, with .alpha.-bromocarboxylates of the general formula III ##STR3## in which R.sup.3 and R.sup.4 have the meanings stated above, wherein the reaction with zinc is carried out in methylene chloride at a temperature ranging from 0.degree. to 50.degree. C.