Cyclopropylamine → 1-(4-Bromophenyl)-3-cyclopropylurea

Beteiligte Stoffe

Reaktionsschritte

Under a nitrogen atmosphere, tetrahydrofuran (80 ml) was added to 4-bromophenyl isocyanate 30 (10.0 g), and a solution of cyclopropylamine 1 (3.17 g) in tetrahydrofuran (20 ml) was added dropwise with stirring under ice-cooling. After the completion of the dropwise addition, the mixture was stirred at room temperature for 3 hrs, and the reaction mixture was concentrated under reduced pressure. Diethyl ether-hexane [1:1 (volume ratio), 100 ml] was added to the residue and, after stirring, the crystals were collected by filtration and dried to give 1-(4-bromo-phenyl)-3-cyclopropyl-urea 31 (12.9 g, over weight) as colorless crystals, which were used for the next step without purification.

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