5 results about "SN2 reaction" patented technology

The present invention relates to the technical field of drug intermediate synthesis, and particularly relates to a preparation method of posaconazole starting material SM3. CeCl3·7H2O and sodium borohydride are added to compound POS-1 for an asymmetric reduction reaction to obtain compound POS-2. Compound POS-2 reacts with 3,5-bis(trifluoromethyl)benzenesulfonyl chloride to obtain compound POS-3. Hydrazine hydrate attacks from the back of compound POS-3 with a larger steric hindrance to undergo an SN2 reaction to obtain a stereoselectively specific compound POS-4. Compound POS-4 then reacts with ethyl formate and forms a salt with oxalic acid to obtain the product posaconazole starting material SM3. By means of asymmetric reduction of carbonyl groups and selective nucleophilic substitution, the present invention effectively avoids the chiral resolution step, thereby reducing the content of isomeric impurities. The prepared product not only has a high ee value, but also the yield is significantly improved, thereby greatly reducing the production cost.

The present invention provides a method for efficiently synthesizing triethyl phosphoacetate, which uses diethyl phosphite and ethyl chloroacetate as reaction raw materials, adds a base (including but not limited to sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, sodium tert-amyloxide and other strong bases), and according to the SN2 reaction characteristics, the P-H bond can be smoothly converted into P in the reaction system. ‑ , thereby further attacking the C-Cl bond of ethyl chloroacetate. The solvation effect of polar aprotic solvents can promote the SN2 reaction. Selecting beneficial solvents (including but not limited to toluene, acetonitrile, dichloromethane, tetrahydrofuran, acetone, ether, ethanol, cyclohexane, etc.) can effectively shorten the reaction time and increase the selectivity of triethyl phosphoacetate. Triethyl phosphoacetate can be obtained in a 92% yield and 99.8% purity after a 0.5-hour reaction at room temperature. This method offers the advantages of low energy consumption, high efficiency, and simple operation steps.

This invention discloses a bispyridyl extractant, its preparation method, and its application as a nickel-cobalt extractant. The bispyridyl extractant has the following structure: wherein R is C 12 ~C 25 The alkyl group is prepared by reacting chloromethylpyridine hydrochloride with a primary amine compound via a bimolecular nucleophilic substitution reaction. This bispyridine extractant has stable physicochemical properties, large saturation capacity, good oil solubility of the extract, and good coordination complexing ability for nickel (cobalt) ions. It can be used in combination with DNNSA or P204 to form a synergistic extraction system for selective extraction and separation of nickel and cobalt in complex metal ion solution systems. It can also be used as a single extraction system for efficient extraction and separation of nickel and cobalt in hydrochloric acid systems, showing good prospects for industrial application.

The invention relates to the technical field of medicine synthesis, and particularly discloses a synthesis process of a bemaprost intermediate. According to the method, B is taken as a starting point of a reaction route, a carbon chain skeleton is constructed through a Grignard reaction, stereo enrichment is realized through enzymatic resolution, a byproduct configuration is converted in combination with a Mitsunobu reaction, finally, a target product is obtained through enzyme hydrolysis, the stereoselectivity of the whole process is good in control, and high enantiomer purity of the product is ensured through chiral recognition of an enzyme and overturning of the configuration through an SN2 reaction.

The invention discloses a novel chiral covalent organic framework material as well as a preparation method and application thereof. The chiral covalent organic framework compound is prepared by the following steps: carrying out Mitsunobo or SN2 reaction, Ullmann coupling and reduction reaction on chiral diol and iodohydroxy ethyl nicotinate to obtain an axial chiral bipyridine aldehyde group monomer, and carrying out Schiff base reaction on the axial chiral bipyridine aldehyde group monomer and a polyamino substituted monomer under a solvothermal condition. The chiral covalent organic framework compound disclosed by the invention can be complexed with various metals such as palladium, copper, nickel and the like to form a heterogeneous catalyst for asymmetric reaction, shows good catalytic effect and chiral selectivity, and also has good chemical stability; after the reaction, separation and recovery of the catalyst can be realized through simple centrifugation or filtration, so that the environmental pollution is effectively reduced, the cost is reduced, and the application prospect is good.