Dimethylformamide → 5-Nitro-N,N-dipropyl-3-benzothiophencarboxamide

Participants

Reaction Conditions

Reaction Steps

45 g of 5-nitro-3-benzothiophencarboxylic acid were suspended in 150 ml of 1,1,1-trichloroethane. 100 ml of thionyl chloride and 0.5 ml of DMF were added. The mixture was refluxed for 2 hours resulting in a clear solution. The solvents were evaporated and remaining thionyl chloride was removed by evaporation twice with toluene. The crystalline product thus obtained was added in small portions to a solution of 60 g of dipropylamine in 500 ml of dichloromethane below 10° C. The mixture was heated to 30° C. and eluted through 200 g of silica gel with 1500 ml of a mixture (1:1) of dichloromethane and ethyl acetate. The organic phase was washed with water, dried (MgSO4) and evaporated. 200 ml of n-heptane were added and the crystalline product filtered off. Yield: 56 g. M.P. 100° C.

Provenance & Evidence