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3 results about "Dithionous acid" patented technology
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Dithionous acid is a sulfur oxoacid with the chemical formula H₂S₂O₄. It is unstable in pure form, but its salts, known as dithionites, are stable. It was initially assumed that the C₂ symmetric structure HOS(=O)-S(=O)OH is the most stable among molecules with the formula H₂S₂O₄ using ab initio calculations. The reason for this is the existence of intermolecular hydrogen bonds. It is now known that dithionous acid spontaneously decomposes to SO₂ and S(OH)₂.
A process for the preparation of an EGFR inhibitor intermediate
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.
Owner:NANJING HAIRUN PHARM CO LTD +1
Process for the preparation of organic sulfinate salts and their use
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.
Owner:CHINA PETROLEUM & CHEMICAL CORP +1
Preparation method of varenicline tartrate intermediate
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.
Owner:ZHUZHOU QIANJIN PHARMA