Abstract: Disclosed herein relates to biopharmaceuticals, and more particularly to a continuous flow method for preparing (R)-3-hydroxy-5-hexenoate. Carbonyl reductase and isopropanol dehydrogenase are co-immobilized onto an inert solid medium simultaneously to prepare a carbonyl reductase/isopropanol dehydrogenase co-immobilized catalyst, which is then filled into a microchannel reactor of the micro reaction system. A solution containing substrate 3-carbonyl-5-hexenoate is subsequently pumped into the microchannel reactor to perform an asymmetric carbonyl reduction reaction to obtain (R)-3-hydroxy-5-hexenoate.

Abstract: Disclosed herein relates to organic synthesis, and more particularly to a method for preparing a key intermediate for the synthesis of statins. The key intermediate is 2-[(4R, 6S)-6-[(benzo[d]thiazol-2-ylthio)methyl]-2,2-di substituted-1,3-dioxan-4-yl] acetate of formula (I): where R1 is a C1-C8 alkyl group, a C3-C8 cycloalkyl group, a monosubstituted or polysubstituted aryl group, or monosubstituted or polysubstituted aralkyl group; R2 is hydrogen, or monosubstituted or polysubstituted C1-C3 alkyl group, or halogen; and R3 and R4 are each independently a C1-C5 alkyl group, a C3-C7 cycloalkyl group, a C3-C7 cycloalkenyl group, a C1-C3 alkoxy group, a C6-C10 aryl group, or C7-C12 aralkyl group. In the method, a halomethyl compound and a thiol reagent are subjected to nucleophilic substitution in an organic solvent to synthesize a thioether, which then undergoes ketal exchange reaction with a carbonyl compound (V) in the presence of an organic acid to obtain a target product.

Abstract: A multi-layered micro-channel mixer includes a base plate and a cover plate. Two inlet fluid reservoirs, two inlet channels, two groups of fluid distribution channel networks, two groups of process fluid channels, an impinging stream mixing chamber, a fluid mixing intensification channel and an outlet buffer reservoir are provided on the base plate. Two fluids are fed into the two inlet fluid reservoirs, respectively. The fluids then flow into the process fluid channels via the inlet channels and the multi-stage fluid distribution channel networks, respectively. Then the two fluid streams ejected from the opposing process fluid channels impinges upon each other in the impinging stream mixing chamber. The mixed fluid is subjected to vortex or secondary flow generated by the baffles or the internals in the impinging stream mixing chamber and fluid mixing intensification channel, and finally the mixed fluid is discharged through the outlet buffer reservoir.

Abstract: A micro-reaction system and a method for preparing 2-methyl-4-amino-5-aminomethyl pyrimidine. A Raney nickel catalyst is modified with formalin, and the modified Raney nickel catalyst is filled into a micro-channel reactor of the micro-reaction system. A substrate solution containing 2-methyl-4-amino-5-cyanopyrimidine and a base and hydrogen are transported to the micro-mixer and the micro-channel reactor in sequence for continuous catalytic hydrogenation to obtain 2-methyl-4-amino-5-aminomethyl pyrimidine.

Abstract: A full continuous flow preparation method of 2-methyl-4-amino-5-aminomethylpyrimidine. A mixed solution of cyanoacetamide, N,N-dimethylformamide and a catalyst is mixed with phosphorus oxychloride in a first micro-mixer, and then the reaction mixture undergoes continuous flow reaction in a microchannel reactor to obtain (dimethylaminomethylene) malononitrile. The reaction mixture is subjected to continuous quenching, extraction and separation, and the organic phase is concentrated, mixed with a methanol solution, and then reacted with an organic base to obtain 2-methyl-4-amino-5-cyanopyrimidine. After the mixed liquid is continuously filtered, the filter cake is dissolved in methanol, mixed with hydrogen in a second micro-mixer, and then transported to a fixed-bed reactor for hydrogenation reaction. The products are concentrated, dried and purified to obtain the desired 2-methyl-4-amino-5-aminomethylpyrimidine.

Abstract: Disclosed herein relates to pharmaceutical engineering, and more particularly to a micro reaction system and a method for preparing 2-methyl-4-amino-5-cyanopyrimidine using the same. An acetamidine hydrochloride solution and an (dimethylaminomethylene)malononitrile solution are separately pumped into the micro reaction system including a micromixer and an agitating microchannel reactor in communication at the same time for a continuous condensation-cyclization reaction to obtain 2-methyl-4-amino-5-cyanopyrimidine.

Abstract: A method for preparing L-carnitine using a micro-reaction system. (R)-4-halo-3-hydroxybutyrate was subjected to quaternization and hydrolysis in an aqueous trimethylamine solution in the presence of an inorganic base in a micro-channel reactor to produce the L-carnitine.

Abstract: This disclosure relates to organic synthesis, and more particularly to a method for preparing 3-chloro-4-oxopentyl acetate using a fully continuous-flow micro-reaction system. In this method, chlorine and an acetylbutyrolactone-containing liquid are simultaneously transported to a first micro-channel reactor for continuous chlorination to obtain ?-acetyl-?-chloro-?-butyrolactone. The reaction mixture is simultaneously transported to a micro-mixer and a second micro-channel reactor together with a mixed solution of glacial acetic acid, hydrochloric acid and water, and the continuous acylation is carried out to obtain 3-chloro-4-oxopentyl acetate. After quenched with a quenching agent, the reaction mixture was subjected to extraction and separation to obtain the 3-chloro-4-oxopentyl acetate.

Abstract: Disclosed herein are a carbonyl reductase variant and its use in the preparation of (R)-4-chloro-3-hydroxybutyrate. The carbonyl reductase variant is obtained by mutating phenylalanine-85 in an amino acid sequence as shown in SEQ ID NO:4 to methionine. An amino acid or amino acids at one or more positions other than position 85 in the amino acid sequence of the carbonyl reductase may be further replaced. The application also provides a recombinant expression vector carrying the gene encoding the carbonyl reductase variant, a genetically-engineered bacterium carrying the carbonyl reductase variant gene and glucose dehydrogenase gene, and an application of this bacterium in the asymmetric reduction of 4-chloroacetoacetate to prepare (R)-4-chloro-3-hydroxybutyrate.

Abstract: The present disclosure relates to the technical field of biochemical engineering and particularly discloses a preparation method for (R)-3-hydroxyl-5-hexenoate. In the method of the present disclosure, the (R)-3-hydroxyl-5-hexenoate is prepared by catalytic reduction of 3-carbonyl-5-hexenoate by ketoreductase with 3-carbonyl-5-hexenoate as the substrate. The amino acid sequence of ketoreductase is shown in SEQ ID NO.1. In the present disclosure, the (R)-3-hydroxyl-5-hexenoate having a very high chiral purity is obtained by asymmetric reduction by ketoreductase as the biocatalyst. The present disclosure has the advantages of easy operation, mild reaction conditions, high reaction yield and good practical industrial application value.

Abstract: The present disclosure belongs to the technical field of organic synthesis and particularly relates to a preparation method for 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate. The 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is a key chiral intermediate for preparation of statin antilipemic agents. In the present disclosure, the 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is obtained by bromination and cyclization of 3-((substituted oxycarbonyl)oxy)-5-hexenoate as raw material with hypochlorite and bromide in an organic solvent in the presence of CO2. The method of the present disclosure has the advantages of readily available raw material, mild reaction conditions, easy operation, low cost, excellent atomic economy and less by-products, and is applicable to industrial production.

Abstract: The present disclosure belongs to the technical field of organic synthesis and particularly relates to a preparation method for 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate. The 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is a key chiral intermediate for preparation of statin antilipemic agents. In the present disclosure, the 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is obtained by bromination and cyclization of 3-((substituted oxycarbonyl)oxy)-5-hexenoate as raw material with hypochlorite and bromide in an organic solvent in the presence of CO2. The method of the present disclosure has the advantages of readily available raw material, mild reaction conditions, easy operation, low cost, excellent atomic economy and less by-products, and is applicable to industrial production.

Abstract: The present disclosure relates to the technical field of biochemical engineering and particularly discloses a preparation method for (R)-3-hydroxyl-5-hexenoate. In the method of the present disclosure, the (R)-3-hydroxyl-5-hexenoate is prepared by catalytic reduction of 3-carbonyl-5-hexenoate by ketoreductase with 3-carbonyl-5-hexenoate as the substrate. The amino acid sequence of ketoreductase is shown in SEQ ID NO.1. In the present disclosure, the (R)-3-hydroxyl-5-hexenoate having a very high chiral purity is obtained by asymmetric reduction by ketoreductase as the biocatalyst. The present disclosure has the advantages of easy operation, mild reaction conditions, high reaction yield and good practical industrial application value.