N-Fluorobenzenesulfonimide → HCID 57900344, compound

Participants

Reaction Conditions

Reaction Steps

To 4H-thieno[3,2-c]chromene-2-carboxylic acid (1.65 g, 7.10 mmol) in THF (70 mL) at −78° C. was added a 1.5 M solution of tert-butyllithium in pentane (15 mL). The resulting solution stirred 1 hr at −78° C. N-fluoro-N-(phenylsulfonyl)benzenesulfonamide (7.2 g, 23 mmol) was added and the reaction warmed to room temperature over 2 hr. The reaction was quenched by the addition of 1 M HCl to effect pH 3. The aqueous layer was extracted with CH2Cl2. The combined organics were dried over Na2SO4, filtered, and concentrated in vacuo to yield 3-fluoro-4H-thieno[3,2-c]chromene-2-carboxylic acid, which contained less than 40% 4H-thieno[3,2-c]chromene-2-carboxylic acid, which was utilized in the next step without purification (1.0 g). MS (Q1) 249 (M)+

Provenance & Evidence