摘要:
A process for the manufacture of (all-rac)-α-tocopherol by the acid-catalyzed reaction of trimethylhydroquinone with isophytol or phytol is characterized by carrying out the reaction in the presence of methane trisulphonate as the catalyst in an organic solvent. The product of the process is the most active and industrially most important member of the vitamin E group.
摘要:
A process for the manufacture of (all-rac)-α-tocopherol by the acid-catalyzed reaction of trimethylhydroquinone with isophytol or phytol is characterized by carrying out the reaction in the presence of methane trisulphonate as the catalyst in an organic solvent. The product of the process is the most active and industrially most important member of the vitamin E group.
摘要:
A method of making (all-rac.)-&agr;-tocopherol by the acid-catalyzed condensation of trimethylhydroquinone with isophytol or phytol wherein the condensation is carried out in the presence of a tris(perfluoroalkanesulphonyl or pentafluorobenzenesulphonyl)methane or a metal salt thereof as the catalyst in an organic solvent. In addition to the metal salt, a Bronsted acid, e.g. sulfuric acid, phosphoric acid or p-toluenesulphonic acid, may be used as a co-catalyst. The product of the method of making is the most active member of the vitamin E group.
摘要:
The present invention is a method of making (all-rac)-&agr;-tocopherol in a reaction having the following steps: a) reacting trimethylhydroquinone and a phytol selected from the group consisting of isophytol and phytol in the presence of a bis(perfluorinated hydrocarbyl sulphonyl)imide catalyst or a metal salt thereof of formula I: [(R1SO2)2N]xR2 (I) wherein each R1, independently, signifies a perfluoroalkyl group CnF2n+1 or a pentafluorophenyl, or both symbols R1 together signify a poly-difluoromethylene group—(CF2)m—, with the proviso that both symbols R1 cannot simultaneously signify trifluoromethyl, R2 signifies a proton or a cationic form of a metal selected from the group consisting of boron, magnesium, aluminum, silicon, scandium, titanium, vanadium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, rhodium, palladium, silver, tin, lanthanum, cerium, praseodymium, neodymium, europium, dysprosium, thulium, ytterbium, hafnium, platinum, and gold, m is an integer from 2 to 4, n is an integer from 1 to 10, and x is the corresponding valency of the proton (1) or the metal cation (1, 2, 3, or 4), in organic solvent; and b) recovering (all-rac)-&agr;-tocopherol from the reaction mixture.
摘要:
A process for the manufacture of 5-cyano-4-lower alkyl-oxazoles is described in which a 5-carbamoyl-4-lower alkyl-oxazole is dehydrated in an organic solvent under mild conditions with cyanuric chloride and an N,N-disubstituted-formamide.
摘要:
A process for the manufacture of a 5-cyano-4-lower alkyl-oxazole by the dehydration of a 5-carbamoyl-4-lower alkyl-oxazole is disclosed. The reaction is carried out by dehydrating the oxazole with silicon tetrachloride in the presence of an amine in an aprotic organic solvent. 5-Carbamoyl-4-methyl-oxazole may be dehydrated by the process in accordance with the invention to obtain 5-cyano-4-methyl-oxazole, which is a valuable intermediate in the synthesis of pyridoxine.
摘要:
A process for the manufacture of d,1-.alpha.-tocopherol by the catalyzed condensation of trimethylhydroquinone with isophytol comprises carrying out the condensation in the presence of bis-(trifluoromethylsulphonyl)amine �HN(SO.sub.2 CF.sub.3).sub.2 ! or a metal salt thereof of the formula Met �N(SO.sub.2 CF.sub.3).sub.2 !.sub.n (I), wherein Met signifies a metal atom selected from the group of lithium, boron, magnesium, aluminium, silicon, scandium, titanium, vanadium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, rhodium, palladium, silver, tin, lanthanum, cerium, neodymium, praseodymium, europium, dysprosium, ytterbium, hafnium, platinum and gold and n signifies the corresponding valency (1, 2, 3, or 4) of the metal atom Met, as the catalyst or of a combination of a metal salt of formula I and a strong Bronsted acid as the catalyst system in an organic solvent. The product of the process is the most active member of the vitamin E group.
摘要:
The present invention relates to a process for the dehydration of amides to nitrites which comprises carrying out the dehydration in the presence of an adduct of sulphur trioxide and an amine as the dehydrating reagent in a basic reaction mixture. Thereby, for example, aliphatic, aromatic and heteroaromatic amides are dehydrated to the corresponding nitrites, such as 5-carbamoyl-4-methyl-oxazole to 5-cyano-4-methyl-oxazole, a valuable intermediate in the synthesis of pyridoxine.
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:
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.