7712-05-2

4,6-Dihydrothieno[3,4-b]thiophene-2-carboxylic acid can be used as organic synthesis intermediates and pharmaceutical intermediates, mainly used in laboratory research and development processes and pharmaceutical and chemical production processes.

Compound 3 was dissolved in ethanol,Potassium hydroxide was added and refluxed at 78 ° C for 4 h,After cooling to room temperature (25 ° C), the reaction solution was extracted with IM HCl, extracted with ethyl acetate, dried over Mg2SO4 and dried to give the title compound 4 (92%).

[1] Patent: CN106317070, 2017, A. Location in patent: Paragraph 0127