Thionyl Chloride → 5-Bromothiophene-2-carbonyl chloride

Beteiligte Stoffe

Reaktionsschritte

Following the procedure of Preparation A, 2.07 g (10.0 mmoles) of commercially available 5-bromo-2-thiophenecarboxylic acid was reacted with 10 ml of thionyl chloride to give 2.35 g of crude 5-bromo-2-thiophenecarbonyl chloride as a red oil. The total crude acid chloride was coupled to 1.76 g (8.33 mmoles) of 5-chloro-2,3-dihydro-2-oxo-1H-indole-1-carboxamide by the procedure in Preparation A using 3.05 g (25.0 mmoles) of 4-(N,N-dimethylamino)pyridine and 50 ml of N,N-dimethylformamide. Acidic workup gave a solid which was recrystallized to give 1.77 g (4.43 moles, 53% yield) of title compound as reddish-brown crystals, m.p. 228°-229° C. (tetrahydrofuran).

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