38results about How to "Reduce racemization" patented technology

The present invention provides an improved process for preparing β-D and β-L 2′-C-methyl-nucleosides and 2′-C-methyl-3′-O-ester nucleosides.

This invention provides an improved asymmetric process for the synthesis of duloxetine involving arylation of Compounds of Formula I.

The invention relates to a dextral lansoprazole freeze-drying preparation, which comprises the following components: dextral lansoprazole, Hydroxypropyl-Beta-Cyclodextrin and PH modifier. The invention also provides a preparation method for the freeze-drying preparation. The freeze-drying preparation obtained according to the technical scheme of the invention can maintain better redissolving performance and solution stability, and enhance the convenience and security of clinical application; and furthermore, the Hydroxypropyl-Beta-Cyclodextrin used in the preparation method plays the function of stabilizer and excipient, that is, on one hand, the racemization of the dextral lansoprazole is effectively reduced, and on the other hand, the freeze-drying preparation obtained through the preparation method is loose, full and integral in appearance and is suitable for industrialized production.

The invention discloses a synthesis method of cyclic pentapeptide. According to the synthesis method, the 'solid-liquid combined production' strategy is adopted, a proper condensation agent is used for a condensation reaction, linear pentapeptides are prepared respectively through a proper process, the cyclization site is located between N-methyl-leucine and leucine, and the efficiency of linear peptide preparation is effectively improved.The proper condensation agent is used for the condensation reaction, racemization in amido bond formation can be effectively reduced, therefore, the purity of a target product can be effectively improved, reaching 99% or above, the requirements of biological activity tests and clinical application can be fully met, and the synthesis method of cyclic pentapeptide has high medical value. The cyclization agent PyBOP is used for a cyclization reaction, the cyclization yield can be effectively increased and reach up to 84.2%.The synthesis method does not require complex purification by column chromatography, redundant amino acids can be simply washed away, the synthesis process is simple, the cost of raw materials is low, reaction conditions are mild, the purity is high, industrialization is easy, and the synthesis method has broad market prospects.

In a first aspect, the present invention relates to a process for producing a stable, injectable solution with low content of noradrenaline, which includes dissolving noradrenaline and optionally an excipient in deoxygenated or degassed water, filtrating the resulting noradrenaline solution in a nitrogen current, distributing the solution in a nitrogen current, and sterilization, preferably hot. The invention further provides a stable, injectable solution with low content of noradrenaline, substantially free of anti-oxidizing and preservative agents, as well as uses thereof in the medical and pharmaceutical fields.

The invention discloses a novel method for preparing an important medical farm chemical intermediate, i.e., S-3-hydroxytetrahydrofuran. The method comprises the following steps of: performing hydroxy group protection on S-4-chloro-3-hydroxybutyrate serving as a raw material; and undergoing a reduction reaction, a cyclization reaction and a deprotection reaction to obtain a target product. A synthesis method disclosed by the invention has the advantages of high optical purity and high yield of the target product, easiness and convenience for reaction operation, environmentally-friendly process and suitability for industrial production.

The invention provides a solid phase method of secretin, which comprises the following steps: 1) selecting an appropriate solid phase carrier; 2) coupling amino acids one by one according to a solid phase synthetic method; 3) splitting for obtaining a crude peptide; 4) obtaining the secretin by purifying the crude peptide, wherein, the solid phase synthesis employs Fmoc-strategy, and false proline is used for replacing parts of serine in the peptide chain during the solid phase synthesis. The solid phase method of secretin provided by the invention has the advantages of simple operation, small impurity, easy purifying and high yield, and is beneficial to realization of industrialization.

Disclosed are a polylactic acid block copolymer and a preparation method thereof. The polylactic acid block copolymer comprises block A and block B, and is presented as B-b-A-b-B triblock structure, wherein the block A is a cyclic aromatic polyester oligomer block, and the block B is a polylactic acid block. The polylactic acid block copolymer is obtained by ring-opening copolymerization of a cyclic aromatic polyester oligomer and a lactide. Disclosed are another polylactic acid block copolymer and a preparation method thereof. The polylactic acid block copolymer comprises block A and block B, and is presented as B-b-A-b-B triblock structure, wherein the block A is an aromatic polyester block with two hydroxyl end groups, and the block B is a polylactic acid block. The polylactic acid block copolymer is obtained by ring-opening copolymerization of an aromatic polyester with two hydroxyl end groups and a lactide.

The present invention discloses solid phase synthesis process of adrenal medullarin (27-52). The synthesis process includes the first solid phase Fmoc polypeptide synthesis to graft protective amino acid Fmoc-Ala-OH onto resin, connecting the rest protective amino acids successively, cutting down the synthesized coarse peptide with peptide cutting reagent, and final separating and purifying to obtain the adrenal medullarin (27-52) as the target peptide. The present invention has mild reaction condition, high reaction rate, less side reactions, easy purification, high yield, no corrosion to the equipment and no environmental pollution.

A process for the preparation of (1S)-QR)-I -azabicyclo[2.2.2.]oct-3-yl 3,4-dihydro-1-phenyl- 2(1H)-isoquino-line carboxylate by reacting (1S)-alkyl 1-phenyl-1,2,3,4-tetrahydro-2-isoquinoline carboxylate with 3-(R)-quinuclidol in an inert solvent, where a primary alkyl ester of the carboxylate whose alkyl length is C₁-C₄ is used and the reaction is catalyzed by a non-nu-cleophilic base.

The present invention provides a process for producing a peptide thioester compound, characterized by comprising: (A) forming a peptide by a solid-phase synthesis method using a resin modified with a linker represented by the formula (1) as a solid phase; (B) cleaving a bond between the solid phase and the peptide with at least one acid selected from dilute hydrochloric acid, dilute sulfuric acid, formic acid, and acetic acid to produce a peptide having a carboxyl group at the C-terminus; and (C) reacting a thiol compound with the peptide at −100 to 0° C. in the presence of a condensing agent in a solvent: (1) wherein R¹ represents C_1-4 alkyl group, R² represents hydrogen atom or C_1-4 alkoxy group, and n represents an integer of 1 to 4.

The invention belongs to the technical field of medicines, and particularly relates to an amrubicin hydrochloride intermediate compound and a preparation method thereof. A novel intermediate is provided, and is used for synthesizing the amrubicin hydrochloride important intermediate. The preparation method solves the problem of low yield caused by chiral resolution of the amrubicin intermediate inthe prior art, and the new intermediate compound synthesized through chirality has the advantages of high product yield, simple operation, substantial reduction of the production cost, and suitableness for industrial production.

Disclosed herein is a method for preparing a hyaluronan-drug conjugate. The method uses the ethyl cyano(hydroxyimino)acetate/diisopropylcarbodiimide coupling system in a homogeneous reaction phase, which unexpectedly improves the substitution rate and substitution efficiency of hyaluronan-drug conjugates for various drugs.