The general procedure for the synthesis of thieno[3,4-B]-1,4-dioxin-2-methanol from the compound (CAS:146796-14-7) was as follows: under nitrogen protection, 135.9 g of 2-hydroxymethyl-2,3-dihydro-thieno[3,4-b][1,4]dioxin-5,7-dicarboxylic acid, 8.3 g (0.10 mol) of copper(II) oxide and 2700.0 g of N,N-dimethylformamide were added to a 5 L four-neck detachable flask equipped with a stirrer, thermometer and condenser tube. The reaction was continuously heated and stirred at 130-132 °C for 8 hours. Upon completion of the reaction, the disappearance of the peak for 2-hydroxymethyl-2,3-dihydro-thieno[3,4-b][1,4]dioxin-5,7-dicarboxylic acid was confirmed by liquid chromatography analysis, and gas chromatography analysis showed the appearance of the main peak. The reaction solution was concentrated and cooled to below 25 ℃, dissolved in 1100 mL of toluene, filtered and washed sequentially with 1% aqueous hydrochloric acid and saturated saline, and concentrated again. The concentrate was purified by column chromatography and 76.0 g of light yellow solid was obtained after drying. The compound was analyzed by 1H-NMR, 13C-NMR and GC-MS, and the gas chromatographic determination showed that the purity of the main component of the obtained compound was 99.4%, which was confirmed to be 2-hydroxymethyl-2,3-dihydro-thieno[3,4-b][1,4]dioxin.
![Thieno[3,4-b]-1,4-dioxin-5,7-dicarboxylic acid, 2,3-dihydro-2-(hydroxymethyl)-](/CAS/20200611/GIF/146796-14-7.gif)
