Tributylphosphine → trans-4-[N-ethyl-N-(2-nitrobenzenesulfonyl)amino]-5,6-dihydro-6-methyl-4-H-thieno-[2,3-b]-thiopyran-7,7-dioxide

Participants

Reaction Conditions

Reaction Steps

cis-4-hydroxy-5,6-dihydro-6-methyl-4-H-thieno-[2,3-b]-thiopyran-7,7-dioxide (5 g), tributylphosphine (6.6 mL) and N-ethyl-2-nitrobenzenesulfonamide (6.17 g) are mixed under nitrogen atmosphere. It is cooled at −20/−30° C. Diisopropyl azadicarboxylate (4.8 mL) is added, maintaining the temperature. It is maintained under stirring, maintaining the temperature, for 4 hours. Tributylphosphine (1.5 mL) and diisopropyl azadicarboxylate (1.5 mL) are added. It is left to reach 20-25° C. and maintained for 30 minutes. It is cooled at 0-5° C.; it is filtered, washed with cold toluene and dried. After purifying by resuspension in methanol, 2.01 g of trans-4-[N-ethyl-N-(2-nitrobenzenesulfonyl)amino]-5,6-dihydro-6-methyl-4-H-thieno-[2,3-b]-thiopyran-7,7-dioxide are obtained.

Provenance & Evidence