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534 results about "Nucleophilic addition" patented technology

In organic chemistry, a nucleophilic addition reaction is an addition reaction where a chemical compound with an electron-deficient or electrophilic double or triple bond, a π bond, reacts with electron-rich reactant, termed a nucleophile, with disappearance of the double bond and creation of two new single, or σ, bonds. The reactions are involved in the biological synthesis of compounds in the metabolism of every living organism, and are used by chemists in academia and industries such as pharmaceuticals to prepare most new complex organic chemicals, and so are central to organic chemistry. Addition reactions require the presence of groups with multiple bonds in the electrophile(due to the fact that double bonds and even triple bonds can both lack electron rich sources): carbon–heteroatom multiple bonds as in carbonyls, imines, and nitriles, or carbon–carbon double or triple bonds. The lack of electron rich sources is due to the fact that these bonds are partially empty, even though they remain connected, since the region occupying the orbital is essentially dead. This electrophilic behavior is defined as empty space since everything inside is basically without any source of electricity except from outside the bond, since bonds tend to want to attract more to themselves(whether this be electric or non-electric can differ in most situations). The addition of the nucleophile means the continuous addition of a negative charge throughout the reaction, unless an electrophile also makes itself present to form a complete structure with no charge at all. The negative charge being continuous throughout the reaction until the formation of an intermediate, bearing the charge, thus is the addition reaction we have before us. Once this meets an electrophile, then the intermediate formed with the negative charge can thus be neutralized to form a complete structure via a type of bond.

Bioprosthetic tissue preparation with synthetic hydrogels

Methods for treating xenogenic tissue for implantation into a human body including in-situ polymerization of a hydrogel polymer in tissue, and tissue treated according to those methods, where the polymerization takes place in tissue that has not been fixed with glutaraldehyde. The polymerization may only fill the tissue, bind the polymer to the tissue, or cross-link the tissue through the polymer, depending on the embodiment. One method includes free radical polymerization of a first vinylic compound, and can include cross-linking through use of a second compound having at least two vinyl groups. Another method utilizes nucleophilic addition polymerization of two compounds, one of which can include PEG and can further include hydrolytically degradable regions. In one embodiment, applicants believe the in-situ polymerization inhibits calcification, and that the polymerization of tissue un-fixed by glutaraldehyde allows for improved penetration of the polymer. The methods find one use in the treatment of porcine heart valve tissue, intended to extend the useful life of the valves by inhibiting calcification. The incorporation of degradable hydrogel regions may initially fill the tissue and reduce any initial inflammatory response, but allow for later infiltration by cells to remodel the tissue.
Owner:MEDTRONIC INC

Preparation method and application of magnetic silicon dioxide composite microsphere

The invention relates to a preparation method and application of a magnetic silicon dioxide composite microsphere. Superparamagnetic ferroferric oxide nano particles of which the diameter ranges from 4 nm to 30 nm are prepared through a high-temperature pyrolysis method, a silicon dioxide shell of which the thickness ranges from 5 nm to 20nm covers the outer surfaces of the magnetic ferroferric oxide nano particles through a reverse microemulsion method, amination modification is conducted on the silicon dioxide surface, glutaraldehyde is used as a crosslinking arm, ligand protein is connected into, and protein separation is conducted through specific binding of ligand protein and target protein. The prepared magnetic microsphere is small in particle diameter and good in monodispersity, the composite microsphere with amine is large in specific surface area, nucleophilic addition is utilized, after the crosslinking arm glutaraldehyde is connected into, multiple kinds of ligand protein can be connected into, and then multiple kinds of target protein can be separated. The method is suitable for rapid separation and application of protein in biological samples, and has wide application prospect and great application value in the biomedical field and other fields.
Owner:HARBIN YICAI NEW MATERIAL

Tulathromycin intermediate and preparation method thereof, as well as preparation method of tulathromycin

The invention provides a tulathromycin intermediate, a preparation method of the tulathromycin intermediate, and a preparation method of the tulathromycin. The preparation method of the tulathromycin has the advantages of mild condition, convenience for operation, and low cost. The preparation method of the tulathromycin comprises the following steps of: using azithromycin A as a raw material; protecting 2'-hydroxy and 6'-amino in the azithromycin A through di-tert-butyl dicarbonate so as to obtain double-protective azithromycin A; carrying out Swern oxidation to 4''-hydroxy to the double-protective azithromycin A; salifying along with trifluoroacetic acid; and synchronously removing boc t-butyloxycarbonyl to obtain the azithromycin A bitrifluoroacetic acid salt of 4''-carbonyl; and then reacting with trimethylsulfonium bromide to obtain 4''-epoxy compound; and finally carrying out nucleophilic addition on the 4''-epoxy compound by n-propylamine so as to obtain the phosphate of tulathromycin; and further neutralizing via alkaline to obtain the target compound tulathromycin; and synchronously obtaining the tulathromycin intermediate of azithromycin A bitrifluoroacetic acid salt of 4''-carbonyl.
Owner:TIANJIN ZHONGSHENG TIAOZHAN BIOTECH

Preparation method of high-purity cefuroxime acid

The invention discloses a preparation method of high-purity cefuroxime acid which is an intermediate for synthesizing second-generation cephalosporins cefuroxime sodium and cefuroxime axetil. The preparation method comprises the following steps: based on 7-aminocephalosporanic acid (7-ACA) as a raw material, carrying out an N-acylation reaction on the 7-ACA and furoyl acetylcholine at the 7-position; at a low temperature, hydrolyzing 3-acetyl with a sodium hydroxide solution, crystallizing, filtering and drying so as to obtain the intermediate 3-deformamido cefuroxime acid (DCC); quantitatively adding the DCC in a tetrahydrofuran solvent, dropwise adding chlorosulfonyl isocyanate for a nucleophilic addition reaction so as to generate chlorosulfonyl cefuroxime acid, and adding purified water for hydrolysis so as to prepare a cefuroxime acid reaction liquid; adding sodium bicarbonate for salifying; removing by-reactant lactone and other unsaponifiable impurities in the reaction liquid with a ternary compound extracting agent of dichloromethane, ethyl acetate and tetrahydrofuran, layering, and adding hydrochloric acid in a water phase for acidification; adding the ternary compound extracting agent to extract and separate out the cefuroxime acid; and removing water-soluble impurities, crystallizing and filtering a distilled organic phase, and then drying so as to obtain the high-purity cefuroxime acid with the purity of more than or equal to 99%.
Owner:四平市精细化学品有限公司

Methyl pyridinium with organic two-photon absorption materia, and preparation method and application thereof

The invention relates to the field of organic nonlinear optical materials and relates to methyl pyridinium with an organic two-photon absorption material, and a preparation method and the application of the methyl pyridinium. The structural formula of the product is described in structural formula (I); the preparation method comprises the steps of taking 2,6-dimethyl pyridine as a raw material and finally obtaining a compound (I) by conducting oxidizing reaction, esterification reaction, methylolation reaction, halogenation reaction, nucleophilic addition reaction, Wittig reaction and the final methylation reaction. The raw materials are easy to access, and the synthesis steps are simple. The compound (I) has excellent two-photon absorption performance and good water solubility and is an ideal biological fluorescence probe; an obvious solvatochromism phenomenon easily occurs, the compound can be used for detecting water content in a common organic solvent, can also be used as a fluorescent probe for detecting the PH value in a solution system, has a series of advantages of high sensibility, quick response, identification by naked eyes and the like, and has an excellent application prospect.
Owner:SHANGHAI NORMAL UNIVERSITY

Epoxy-resin-modified polyurethane waterproof paint and preparation method thereof

The invention discloses epoxy-resin-modified polyurethane waterproof paint and a preparation method thereof. The epoxy-resin-modified polyurethane waterproof paint comprises the following components according to the parts by weight: 80-100 parts of polyether glycol, 20-40 parts of isophorone diisocyanate, 30-50 parts of an epoxy resin, 2-6 parts of hydroxy-terminated poly-dimethylsiloxane, 0.04-0.2 parts of chloroplatinic acid, 0.6-1 part of a silane coupling agent, 2-6 parts of dimethylolpropionic acid, 15-25 parts of acetone, 4-10 parts of trimethylamine, 0.02-0.5 parts of dibutyltin dilaurate, 5-10 parts of water, and 30-60 parts of inorganic filler. The preparation method comprises the following steps: S1: modifying the epoxy resin; S2: under the protection of nitrogen in 65-75 DEG C,performing a nucleophilic addition reaction of the polyether glycol; S3: in 70 DEG C, copolymerizing reaction products in the steps S1 and S2 and the dimethylolpropionic acid; and S4: neutralizing andhomogenizing. The epoxy-resin-modified polyurethane waterproof paint is capable of using the mutual crosslinking modification of polydimethylsiloxane, the epoxy resin and polyurethane, synthesizing the advantages of three parties, and improving the structure stability and the mechanical property of a coating film. The produced polyurethane waterproof paint can be tightly adhered to a non-polar base plane, and excellent in waterproof anti-penetrability performance.
Owner:ANHUI LENCAQI BUILDING MATERIAL

DOPO (9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) derivative grafted siloxane flame retardant reaction type cable material and preparation method thereof

The invention discloses a DOPO (9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) derivative grafted siloxane flame retardant reaction type cable material, which is prepared through the steps that firstly, KH-570-TiO2 particles are successfully synthesized by a sol-gel combined hydrothermal method; vinyl groups are introduced on the surfaces of the nanometer titania particles; ethenyltrimethoxysilan is used as a raw material to take a hydrolytic polycondensation reaction to prepare octavinyl polyhedral oligomeric silsesquioxane; the octavinyl polyhedral oligomeric silsesquioxane and DOPO take a nucleophilic addition reaction; an obtained DOPO derivative is used as a reaction type flame retardant; then, the flame retardant and nanometer TiO2 with double bonds are grafted on a polyethylene molecular chain by using peroxide as an initiator to obtain grafted aggregates; then, cross-linking reaction is performed in hot water to obtain the cable material. The reaction type flame retardant is connected with a polymer matrix through chemical bonds, so that the problem of compatibility is avoided; the influence on the mechanical property of the cable material is little; in addition, the flame retardant effect is durable.
Owner:ANHUI CHUNHUI INSTR CABLE GROUP
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