39results about How to "No racemization" patented technology

The invention discloses a method for reducing amide compounds, which reduces various amides through low valent tiron. Low valent tiron prepared by reducing titanium tetrachloride through magnesium powder is reacted with amide in tetrahydrofuran at 0 DEG C or normal temperature so as to obtain corresponding amine. The method has the advantages that the reaction condition is mild, reagent adopted is chip and easy to get, the method is convenient to operate, substrate has a wide applicable scope, functional group has good compatibility, the reaction is rapid, and the yield is high.

The invention discloses a method for preparing furanone compounds, and provides a method for preparing a furanone compound III. The method includes the following steps that in a solvent, in the presence of inorganic salt, a compound II and a reducing agent are subjected to a reduction reaction, and the furanone compound III is obtained; the solvent is a fatty alcohol solvent or a mixed solvent of a fatty alcohol solvent and water. The brivaracetam can be prepared with the furanone compound III only with the three steps, and the synthetic route is short; the ee value of the compound II is larger than 99.0%, racemization does not occur in the reaction process, and the de value of a brivaracetam I crude product is larger than 99.0%; the brivaracetam I crude product is further purified through a crystal instead of a chirality high-pressure-liquid-phase preparing column, and the chirality purity of brivaracetam I can be further increased to be the de value of 99.80% or above; meanwhile, the content of other individual impurities of the brivaracetam I is smaller than 0.1%, and reaches the API level, and the method is suitable for industrial production. The formula is defined in the description.

The invention discloses a method for extracting synephrine from ripe navel orange peel, which comprises the following steps: (1) crushing the dried navel orange peel and mixing it with distilled water, adding a compound enzyme for enzymolysis to obtain an enzymolysis mixture; 2) The enzymolysis mixture is subjected to ultra-high pressure deactivation treatment, and the pH is adjusted to 5.0-6.0, and then subcritical extraction is carried out under the protection of nitrogen, and the supernatant is collected by centrifugation after extraction; (3) The molecular cut-off is 5000u~ A 10000u ultrafiltration membrane is used to perform ultrafiltration separation on the supernatant obtained in step (2), and collect the concentrate; (4) mix and stir the concentrate obtained in step (3) with ethanol, and the resulting mixture is filtered under reduced pressure and frozen Dry to get synephrine. The method has the advantages of high extraction rate and extraction efficiency, mild treatment conditions, and environmental friendliness.

A prepartion method of N-acetyl-L-carnosine, relates to pharmaceutical intermediates synthesis technology field. Dissolving p-nitrophenol into organic solvent, reacting with acetyl chloride to obtain active ester solution at the presence of acid-binding agent; dissolving the L-carnosine and protection agent into water to obtain aqueous solution, then adding the avtive ester solution into the aqueous solution for reacting, and when the reaction is finished, demixing, decoloring the water layer and decompressing condensing to pulpous state, then mixing the condensed residue with acetate acid andadding into polar solvent for stirring, cold separating and drying to obtain the N-acetyl-L-carnosine. The advantages are: the molar yield is more than 90%, the chemical purity is more than 90%, therefore high yield and ideal purity is suitable for industrial production.