Analyzing the synthesis route of 3622-35-3

3622-35-3 Benzo[d]thiazole-6-carboxylic acid 601670, athiazole compound, is more and more widely used in various fields.

With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.3622-35-3,Benzo[d]thiazole-6-carboxylic acid,as a common compound, the synthetic route is as follows.

Under nitrogen atmosphere at -78 C, 11BuLi/Hex(2.5M) (28.5 mL, 71.4 mmol) was added dropwise into the solution of 6-carboxybenzothiazole (6.566 g, 37 mmol) in THF (450 mL) over 25 minutes. After the mixture was stirred for additional half an hour, the solution of Boc-HN-Arg(Mtr) Weinreb amide (1.633 g, 3.08 mmol) in THF (60 mL) was added slowly over 20 mm at -78C. After the addition then the mixture was stirred at -24 C to -20 C for 1.5 hours. The reaction was quenched with saturated aqueous NH4C1 (270 mL). The layers were separated and the aqueous layer was extracted with AcOEt. The organic phase was collected and washed with water and brine, dried with Na2SO4 then concentrated in vacuo. To the resulting residue MeOH (50 mL) was added. The mixture was cooled at -25 C and sodium borohydride (0.706 g, 18.7 mmol) was added. The mixture was stirred at -25 -20 C for 1 hour. Acetone (10 mL) was added to quench the reaction and the mixture was stirred for 15 minutes then concentrated in vacuo. The residue was suspended in water, acidified to pH 34, and extracted with AcOEt. The organic phase was washed with brine, dried with Na2SO4, then concentrated in vacuo. The resulting residue was dissolved in CH2C12/MeOH (17/3 v/v, 40 mL), cooled to 0 C. Into it, (trimethylsilyl)diazomethane (2 M in hexane, 9.2 mL, 18.4 mmol) was added dropwise over 25 minutes. The mixture was stirred at 0 C for ihour. MeOH (5 mL) was added and the mixture was concentrated in vacuo. The residue was purified by silica gel chromatography with CHC13/MeOH combination as eluent to give BocHN-Arg(Mtr)-CH(OH)benzothiazole-6-COOMe a (0.445 g, mixture of diastereomers) in 22% yield. MS(ESI): found: [M + Hj, 664.5., 3622-35-3

3622-35-3 Benzo[d]thiazole-6-carboxylic acid 601670, athiazole compound, is more and more widely used in various fields.

Reference:
Patent; WASHINGTON UNIVERSITY; JANETKA, James,, W.; HAN, Zhenfu; HARRIS, Peter; KARMAKAR, Partha; (163 pag.)WO2016/144654; (2016); A1;,
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