1,8-Diazabicyclo(5.4.0)undec-7-ene → 4-(2-Chlorophenyl)-2-ethyl-5-nitrothieno[2,3-b]pyridine

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Reaction Steps

To a solution of DBU (5.1 g) in benzene (50 ml) was added dropwise a solution of 3-(2-chlorobenzoyl)-2-(2-nitroethenylamino)-5-ethylthiophene (5.1 g) in dioxane-benzene (1 : 1, 30 ml}over one hour with stirring under reflux. After refluxing for additional one hour, the mixture was washed with water and dried over MgSO4. The solvent was distilled off and to the residue was added isopropyl ether to obtain 4-(2-chlorophenyl)-2-ethyl-5-nitrothieno[2,3-b]pyridine as crystals (4.3 g, 89.0%). The crystals were recrystallized from isopropyl ether to obtain pale yellow prisms, mp: 72°-73° C.

Provenance & Evidence