摘要:
Disclosed is a single step continuous hydrogenation process for the preparation of 3-methyl-tetrahydrofuran from alpha-methylene-gamma-butyrolactone, in the presence of a catalytic metal.
摘要:
A new, more efficient and highly stereospecific process is described for the preparation of compounds with general formula (R)-(I) and of absolute configuration (R), where the groups M, W, Q and Q1 are as defined in the description, starting from compounds of absolute configuration (S) by hydrolysis, in the presence of acids, of the corresponding esterified derivatives. The (R)-(I) products obtained with the process described herein are chiral synthons useful for the production of enanthiomerically pure drugs. The preparation of (R)-carnitine is also provided.
摘要:
Processes are disclosed for the preparation of 2-methylfuran and 2-methyltetrahydrofuran. The continuous vapor-phase processes are commercially viable and efficient because they permit the preparation of 2-methylfuran and 2-methyltetrahydrofuran using commercially-available catalysts, namely, a reduced copper-based catalyst consisting essentially of cupric oxide, chromium (III) oxide, manganese oxide and barium chromate and a reduced nickel-based catalyst consisting essentially of nickel, nickel (II) oxide, aluminum oxide and silica. An apparatus comprising two inline hydrogenators is used for preparing the 2-methylfuran or 2-methyltetrahydrofuran.
摘要:
Compositions that comprise at least one compound that corresponds to general formula (I): in which n is a number from 0 to 20; R1, R2, R3 and R4 each represent a hydrogen atom or a hydrocarbon radical, for example alkyl, with 1 to 30 carbon atoms, whereby at least one of R1, R2, R3, and R4 is a hydrocarbon radical; and m is a number from 1 to 30, can be prepared by a process that comprises the reaction of a hydroxymethylated derivative of tetrahydrofuran with ethylene oxide, then with one or more other epoxidized compounds. These compositions can be used as detergent additives for gasoline-type fuels.
摘要:
Disclosed is a hydrogenation process for the preparation of 3-methyl-tetrahydrofuran from 2-methyl-gamma-butyrolactone. The above process enables the production of the objective highly pure 3-methyl-tetrahydrofuran free from alcohol in high efficiency and high conversion through a simple production step.
摘要:
The invention is directed to a method for synthesizing C-glycosides of ulosonic acids, as well as intermediates thereof and C-glycosides prepared by this method.
摘要:
A process for preparing a 3-hydroxy-&ggr;-butyrolactone derivative represented by the following formula (1): wherein R is C1-C6 alkyl, 3 to 6-membered cycloalkyl, aralkyl, 2-alkenyl, acyl, &agr;-hydroxyalkyl, alkoxycarbonylalkyl or alkoxycarbonyl, which is characterized in treating 3-hydroxy-&ggr;-butyrolactone with a metal salt of hexamethyldisilazane and then, reacting it with an electrophilic reagent, optionally in the presence of a reaction promoter.
摘要:
Tetrahydrofurans suitable for use as starting materials in the synthesis of polyether polyols without causing coloration in the product polyether polyols can be obtained by contacting crude tetrahydrofurans with a mineral acid or a strongly acidic cation-exchange resin, followed by isolation through a simple distillation and/or rectification to obtain purified tetrahydrofurans.