Potassium Fluoride → Dimethyl [2,2'-bithiophene]-5,5'-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

In a microwave tube, N-(5-iodo-4-methyl-1,3-thiazol-2-yl)acetamide, Intermediate 1 (150 mg; 0.53 mmol; 1 eq) and Pd(dppf)Cl2 (19.5 mg; 0.03 mmol; 0.05 eq.) are suspended in Toluene (3 ml). Potassium fluoride (123.6 mg; 2.13 mmol; 4 eq.) is dissolved in MeOH (3 ml) and is added to the first solution. Methyl 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylate, Intermediate 2 (213.8 mg; 0.80 mmol; 1.50 eq.) is finally added. The resulting solution is flushed with argon, the tube is closed and heated under microwave action at 120° C. for 10 minutes. The desired product is formed together with [2,2′]-bithiophenyl-5,5′-dicarboxylic acid dimethyl ester, the homocoupling product of methyl 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylate. Solvents are evaporated and the crude product is purified by preparative HPLC, affording Compound (16) as white-off solid (180 mg; 57%). 1H NMR (DMSO-d6) δ 2.15 (s, 3H), 2.45 (s, 3H), 3.82 (s, 3H, OCH3), 7.24 (d, J=4.5 Hz, 1H), 7.76 (d, J=4.5 Hz, 1H), 12.31 (s, 1H). M−(ESI): 295.10; M+(ESI): 297.12. HPLC, Rt: 3.21 min (purity: 99.6%).

Provenance & Evidence