摘要:
The present invention relates to a novel process for the manufacture of Grewe-diamine comprising the following step: hydrolyzing a compound of formula (II), wherein R is hydrogen or straight- or branched chain C1-4 alkyl, with an aqueous alkali or alkaline-earth metal hydroxide solution, characterized in that the hydrolysis is carried out in the presence of an organic solvent.
摘要:
The present invention relates to an improved process for the production of 1,3,3-trimethyl-2-(3-methylpent-2-en-4-ynyl)cyclohex-1-ene, highly enriched in the Z-isomer, and the use of such compounds in organic syntheses, especially in processes forming intermediates (building blocks) the synthesis of vitamin A or β-carotene or other carotenoids, e.g. canthaxanthin, astaxanthin or zeaxanthin.
摘要:
Use of pure lanthanum oxide which is obtained by calcination of oxygen-containing lanthanum salts at temperatures of at least 700° C. as heterogeneous catalyst in the aldol condensation of citral and acetone to give pseudoionone, and process for the preparation of pseudoionone by aldol condensation of citral and acetone in the liquid phase using pure lanthanum oxide.
摘要:
A process for the preparation of 1-ethynyl-3,3-dimethylcyclohexan-1-ol from dimedone by a reaction sequence of reduction and ethynylation and its further transformation into green ketone.
摘要:
The present invention is directed to a process for the manufacture of 3,7-dimethyl-1-octen-3-ol comprising the following steps: a) hydrogenation of 6-methyl-5-hepten-2-on to 6-methyl-2-heptanon in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of carbon, calcium carbonate and aluminum oxide. b) reaction of 6-methyl-2-heptanon with acetylene to 3,7-dimethyl-1-octin-3-ol in the presence of ammonia and potassium hydroxide and in the absence of any additional organic solvent; c) hydrogenation of 3,7-dimethyl-1-octin-3-ol to 3,7-dimethyl-1-octen-3-ol in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of calcium carbonate, aluminum oxide, silica, porous glass, carbon or graphite, and barium sulphate, with the proviso that the catalyst additionally contains lead when the carrier is calcium carbonate. The present invention is further directed to a process for the manufacture of isophytol and vitamin E, where a thus produced 3,7-dimethyl-1-octen-3-ol is used as starting material.
摘要:
A method for acylating tertiary alcohols and phenolic compounds with carboxylic acids or their anhydrides in micro-reaction systems wherein the acylation is effected in the absence of any catalyst including water at residence times of at most 30 minutes.
摘要:
The present invention is directed to a process for the manufacture of 2,3,5-trimethyl-hydro-p-benzoquinone comprising the following steps: a) hydrogenating 2,6-dimethyl-p-benzoquinone with hydrogen in the presence of a hydrogenation catalyst in an organic solvent to obtain 2,6-dimethyl-hydro-p-benzoquinone; b) reacting 2,6-dimethyl-hydro-p-benzoquinone with a secondary amine and formal-dehyde in an organic solvent to obtain 2,6-dimethyl-3-(N,N-disubstituted aminomethyl)-hydro-p-benzoquinone; c) reacting 2,6-dimethyl-3-(N,N-disubstituted aminomethyl)-hydro-p-benzoquinone with hydrogen in the presence of a hydrogenolysis catalyst in an organic solvent to obtain 2,3,5-trimethylhydro-p-benzoquinone; wherein the organic solvent in all steps a), b) and c) is independently selected from the group consisting of methyl tert.-butyl ether, ethyl tert.-butyl ether, tert.-amyl ether, methoxycyclopentane and any mixtures thereof. Preferably the organic solvent used in all steps a), b) and c) is the same.
摘要:
Isomerization of β-keto-allenes of the general formula I wherein R1 is hydrogen, methyl or ethyl, in particular hydrogen or methyl; R2 is hydrogen or methyl; R3 is hydrogen or methyl, in particular methyl and R4 is an aliphatic hydrocarbon residue containing 1-37 carbon atoms, into corresponding α,γ-dienones of formula II by treatment with a basic ion exchange resin.