Benzaldehyde → 5-Benzylidene-2,4-thiazolidinedione

Participants

Reaction Steps

The sulfonamide derivatives 2-5 and 2-6 are prepared as depicted in Scheme 2. The bis-aryl iodonium tetrafluoroborate 2-1 is coupled with 4-hydroxybenzoate 1-2 at room temperature in dichloromethane in the presence of copper bronze and a suitable base such as triethylamine (TEA) to afford diaryl ether 2-2. Reduction of ether 2-2 with DIBAL furnishes the corresponding alcohol which is oxidized to benzaldehyde 2-3 with manganese dioxide. Condensation of aldehyde 2-3 with thiazolidinedione produces an intermediate benzylidene thiazolidinedione which is hydrogenated to furnish benzyl thiazolidinedione 2-4. A subsequent chlorosulfonylation reaction yields a 3′-sulfonyl chloride which is then reacted with a primary or secondary amine to afford 3′-sulfonylamide 2-5. Demethylation of 2-5 with boron tribromide gives hydroxysulfonamide 2-6.

Provenance & Evidence