Benzoyl isocyanate → Tert-butyl 5-(3-benzoylureido)-4-cyano-3-methylthiophene-2-carboxylate

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Reaction Steps

To a solution of tert-butyl 5-amino-4-cyano-3-methylthiophene-2-carboxylate (example 64b) (16 g, 67.14 mmol) in dioxane (200 mL), was added benzoyl isocyanate (10 g, 67.14 mmol). The reaction mixture was stirred at rt overnight, and upon completion was diluted with EtOAc, washed with NaHCO3, water, brine, dried over MgSO4, filtered and concentrated to yield tert-butyl 5-(3-benzoylureido)-4-cyano-3-methylthiophene-2-carboxylate (21.78 g, 84%) as a brown solid. 1H NMR (400 MHz, DMSO-d6) δ 1.54 (s, 9H), 3.58 (s, 3H), 7.58 (t, J=7.5 Hz, 2H), 7.71 (t, J=7.5 Hz, 1H), 7.88 (d, J=7.5 Hz, 1H), 8.05 (d, J=7.5 Hz, 2H), 12.25 (br s, 1H).

Provenance & Evidence