New method of synthesizing 2,4-di-substituted benzothiazole
A technology of benzothiazole and disubstitution, applied in the field of synthesizing 2,4-disubstituted benzothiazole, which can solve the problems of low yield, cumbersome process, and low yield in the ring-closing step
Inactive Publication Date: 2015-08-12
CHONGQING UNIV
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Problems solved by technology
[0003] The traditional preparation method of 2,4-disubstituted benzothiazole, the process is cumbersome and the yield is low
Another method is to prepare benzamide from the reaction of 2-aminobenzoic acid methyl ester and benzoyl chloride, which is converted into thiobenzamide and then ring-closed to prepare 4-ester group benzothiazole, but the ring-closing step yield very low
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[0007] Below in conjunction with concrete reaction, further illustrate the present invention. Take R' as a trimethylacetyl group and R as a phenyl group as an example.
[0008] Trimethylacetyl-protected thioamide substrate (88.6 mg, 0.4 mmol, 1.0 equiv.), CsF (304 mg, 2 mmol, 5.0 equiv.) was dissolved in 1,4-dioxane (30 mL) reaction solvent , TPBT (268.0 mg, 0.6 mmol, 1.5 equiv.) in 1,4-dioxane (10 mL) was slowly added to the reaction solution at 80° C. over 8 hours, mixed uniformly and reacted.
[0009] Post-processing: After the reaction, the solvent was removed by a rotary evaporator, and the product 2-phenyl-4-trimethylacetylbenzothiazole was obtained by separation and purification on a silica gel column with a yield of 75%.
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A new method of synthesizing 2,4-di-substituted benzothiazole is disclosed, wherein R and R' both can be aryl groups, alkyl groups and heterocyclic ring groups. The method includes the steps of mixing a substituted thioamide substrate and a fluorine-containing alkali with a reaction solvent 1,4-dioxane, adding a known benzyne precursor slowly into the reaction solution to prepare 2,4-di-substituted benzothiazole, and performing column chromatographic purification to obtain a finish product of which the yield is 75%. The new method is low in raw material cost and the raw material is easy to obtain. The new method is simple in operation, is less in synthetic steps, is high in yield and has important application value in the fields of pharmaceutical chemistry and organic synthesis.
Description
technical field [0001] The invention proposes a new method for synthesizing 2,4-disubstituted benzothiazoles. Background technique [0002] Benzothiazoles are widely used in organic synthesis, functional materials, fragrances, especially in organic synthesis and medicinal chemistry. Benzothiazole itself has strong biological activity. It is traditionally an important intermediate in the synthesis of anti-tumor, anti-epileptic drugs and anti-inflammatory drugs, and has also been applied to anti-bacterial drugs, anti-inflammatory drugs, and diabetes drugs. This year's research found that 2,4-disubstituted benzothiazole, especially the structure with a carboxylic acid group or amide group at the 4th position of benzothiazole can target poly(ADP-ribose) polymerase (PARP) PARP has a certain inhibitory effect, and PARP is a popular target for anti-tumor drug research in recent years. [0003] The traditional preparation method of 2,4-disubstituted benzothiazole is cumbersome and...
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IPC IPC(8): C07D277/66
CPCC07D277/66
Inventor 李杨王娟
Owner CHONGQING UNIV
