6 results about "Dithionous acid" patented technology

This invention provides a method for preparing an EGFR inhibitor intermediate (compound of formula V), using dithionite as a reducing agent to prepare compound V from compound IV; the preparation method has higher safety and is more conducive to industrial production.

The application provides a preparation method of high-content 2-trifluoromethyl-4-heptafluoroisopropylaniline, in which 2-trifluoromethyl aniline and 2-bromine heptafluoropropane are reacted in the presence of hydrosulfite, a solvent and a catalyst to obtain high-content 2-trifluoromethyl-4-heptafluoroisopropylaniline through reaction and post-treatment; the catalyst is selected from phosphoric acid, pyrophosphoric acid, hypophosphorous acid, metaphosphoric acid, phosphorous acid, pyrophosphorous acid, hydrobromic acid, hydrogen bromide gas, hydrogen chloride gas or sodium bisulfite. The preparation method is simple in operation and mild in chemical reaction conditions; under the preferred reaction conditions, the conversion content reaches more than 96% in one reaction, the post-treatment steps are few, rectification is not needed, the content of the final product is more than 98%, the total reaction yield is more than 93%, the industrial production is easy, and the method has a high application prospect.

The invention relates to the technical field of organic synthesis, in particular to a reduction method of alpha, beta-unsaturated carboxylic acid, which is characterized in that alpha, beta-unsaturated carboxylic acid is contacted with dithionite, and selective reduction of water-soluble alpha, beta-unsaturated carboxylic acid can be realized in water or a water-soluble solvent under mild conditions. The reduction method has the advantages of being high in total yield, high in product purity, simple in reaction condition, convenient to operate, capable of achieving large-scale preparation, wide in substrate selection range and the like, can be used for converting the 5-carboxyl deoxycytosine into the dihydrouracil, and is used for methylation site detection in combination with technologies such as sequencing or mass spectrum. Compared with a borane pyridine complex with certain explosion risk used in the existing TAPS, the reagent used in the invention has higher safety.

The application relates to the technical field of organic synthesis, and discloses a preparation method of an organic sulfinate salt, characterized in that the method comprises the following steps: performing a nucleophilic addition reaction by contacting a compound shown in formula I or a compound shown in formula I' with a compound shown in formula II; and the nucleophilic reagent is at least one selected from nitrogen-substituted or unsubstituted dithionous acid and esters and salts thereof. The preparation method has high yield and excellent selectivity, and no organic sulfonic acid sodium salt is generated in by-products. The solubility difference between urea in the by-products and the product sulfinate sodium salt is large, subsequent recrystallization and purification operations are simple, the solvent consumption is small, and the separation efficiency is high.

The present invention discloses a flotation separation method for a copper-molybdenum mixed concentrate and a combined depressant used therein. The combined depressant comprises dithionite and thiobarbituric acid. The method involves adding dithionite to the copper-molybdenum mixed concentrate slurry for drug removal, then adding thiobarbituric acid to depress chalcopyrite, and then adding a molybdenite collector and a frother for flotation, thereby obtaining molybdenum and copper concentrates. The combined depressant is non-toxic and environmentally friendly, and the synergistic effect of the two depressants achieves excellent chalcopyrite inhibition at relatively low dosages, significantly improving molybdenum recovery and molybdenum-copper separation efficiency.

The invention belongs to the technical field of chemical medicine raw material medicine and preparation manufacturing, and particularly relates to a preparation method of a varenicline tartrate intermediate. According to the present invention, 2, 3, 4, 5-tetrahydro-7, 8-dinitro-3-(trifluoroacetyl)-1, 5-methylene-1H-3-benzaza is adopted as a raw material, and the 2, 3, 4, 5-tetrahydro-7, 8-diamino-3-(trifluoroacetyl)-1, 5-methylene-1H-3-benzaza is prepared through the reduction of disulfurous acid or a salt thereof, such that the method does not need to use hydrogen pressurization, can be used for preparing the 2, 3, 4, 5-tetrahydro-7, 8-diamino-3-(trifluoroacetyl)-1, 5-methylene-1H-3-benzaza, and can be used for preparing the 2, 3, 4, 5-tetrahydro-7, 8-diamino-3-(trifluoroacetyl)-1, 5- meanwhile, the use of heavy metal palladium is avoided, the reaction condition is mild, the cost is low, the target product yield is high (greater than 75%), the purity is excellent (greater than 97%), and the industrial production of varenicline tartrate is facilitated.