Oxalyl chloride → 4-Chloro-7-(3-fluoro-benzyl)-2-methyl-6-oxo-6,7-dihydro-thieno[2,3-b]pyridine-5-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

Oxalyl chloride (4.83 mL, 0.055 mol) was added to a solution of 7-(3-fluoro-benzyl)-4-hydroxy-2-methyl-6-oxo-6,7-dihydro-thieno[2,3-b]pyridine-5-carboxylic acid ethyl ester (69) (8 g, 0.022 mol) in DMF at −30° C. under argon. The temperature was raised gradually to 75° C. and stirred for 3 h. The solution was cooled and poured into ice water. The solids formed were filtered, washed by cold water and dried to yield 6.8 g (82%) of 4-chloro-7-(3-fluoro-benzyl)-2-methyl-6-oxo-6,7-dihydro-thieno[2,3-b]pyridine-5-carboxylic acid ethyl ester. 1H-NMR (DMSO-d6) δ 1.30 (t, J=7.2 Hz, 3H), 2.45 (d, J=1.2 Hz, 3H), 4.33 (q, J=7.2 Hz, 2H), 5.31 (s, 2H), 7.05 (d, J=1.2 Hz, 1H), 7.09-7.17 (m, 3H), 7.40 (m, 1H) ppm, EIMS m/z 380 (M+1).

Provenance & Evidence