Thieno(3,2-c)pyridine → 1-(Thieno[3,2-c]pyridin-2-yl)ethanone

Participants

Reaction Conditions

Reaction Steps

A solution of thieno[3,2-c]pyridine (5.0 g) in 75 mL THF (tetrahydrofuran) was cooled to −45° C. in a CH3CN/dry ice bath. n-Butyllithium (1.6M in hexanes) (35.0 ml) was added dropwise maintaining the internal temperature at or below −40° C. The addition took about 45 minutes. The reaction was stirred for 1 hour at −45° C. N-methyl-N-methoxyacetamide in 5 mL THF was added and as a result the reaction warmed to −30° C. The reaction was stirred at −45° C. for 1.5 hours. The reaction was quenched with saturated NH4Cl. The aqueous layer had a pH of about 8. The aqueous layer was extracted three times into EtOAc. The combined organic extracts were washed with brine and dried over MgSO4. The material was filtered, concentrated on a rotary evaporator and subjected to column chromatography (Biotage Horizon system, 120 g Analogix column, equilibrate with hexanes, elute with 50% EtOAc/hexanes). The most pure fractions were concentrated on a rotary evaporator and then triturated with Et2O to remove some color and collect a pale orange solid by filtration (2.667 g).

Provenance & Evidence