Hydrochloric Acid → 5-(1-benzyl-1H-imidazol-2-yl)-2-bromo-4-(2,4-dichlorophenyl)thiophene-3-carbonitrile

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Reaction Conditions

Reaction Steps

N-benzyl-5-bromo-4-cyano-3-(2,4-dichlorophenyl)thiophene-2-carboxamide (0.180 g, 0.386 mmol) was dissolved in DCM (2 mL) and phosphorus pentachloride (0.0884 g, 0.425 mmol) and 4.00 M of Hydrochloric acid in 1,4-dioxane (0.050 mL, 0.20 mmol) were added. The mixture was heated in a sealed vial at 60° C. for 2 hours. After cooling down to room temperature, aminoacetaldehyde dimethyl acetal (0.252 mL, 2.32 mmol) was slowly added. The mixture was heated at 60° C. for additional 1 hour. After cooling to room temperature, 4.00 M of Hydrochloric acid in 1,4-dioxane (1.0 mL, 4.0 mmol) was added and the mixture was heated at 60° C. for 2 hours and at room temperature overnight. Solvent was concentrated and the residue was diluted with EA, washed with saturated NaHCO3, brine, dried with Na2SO4, filtered and evaporated. The residue was purified using ISCO chromatography on silica gel, elution with 10-25% EA in hexanes to give the product (0.110 g, 58%). LCMS: (FA) ES+, 488, 490, 492. 1H NMR (300 MHz, d1-chloroform) δ: 7.28 (d, J=2.07 Hz, 1H), 7.26-7.15 (m, 5H), 7.11-7.08 (d, J=8.29 Hz, 1H), 6.85 (s, 1H), 6.73-6.70 (dd, J=6.97 Hz, 1.66 Hz, 2H), 4.85-4.70 (m, 2H).

Provenance & Evidence