116118-99-1

116119-00-7

116118-99-1

Step 3: Synthesis of 4,5,6,7-tetrahydrothieno[3,2-c]pyridine-2-carboxylic acid hydrochloride Dimethyl 6,7-dihydrothieno[3,2-c]pyridine-2,5(4H)-dicarboxylate (1.76 mmol) was dissolved in 3.5 N KOH solution (3 mL) and the reaction was carried out at reflux for 3 hrs (the progress of the reaction was monitored by TLC). Upon completion of the reaction, the reaction mixture was cooled to 0 °C and acidified with concentrated hydrochloric acid to pH < 2. The precipitated solid was collected by filtration and washed with cold water and dried under vacuum to afford the target product 4,5,6,7-tetrahydrothieno[3,2-c]pyridine-2-carboxylic acid hydrochloride. Yield: 30%.