Citric Acid → 1-{1-[4-(4-amino-3,5-dibromophenyl)-1,4-dioxobutyl]-4-piperidinyl}-1,3-dihydro-4-phenyl-2(2H)-imidazolone

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Reaction Steps

A mixture of 1.0 g (2.849 mmol) of 4-amino-3,5-dibromo-γ-oxo-benzenebutanoic acid, 1.04 g (2.91 mmol) of 1,3-dihydro-1-(4-piperidinyl)-4-phenyl-2(2H)-imidazolone, 0.935 g (2.912 mmol) of TBTU, 1.02 ml (5.77 mmol) of DIEA and 50 ml of tetrahydrofuran was stirred for 1 hour at ambient temperature. The reaction mixture was diluted with 300 ml of water and acidified slightly with citric acid. The precipitate formed was suction filtered and washed carefully with water, then with 3 ml of tetrahydrofuran, and finally dried in a circulating air dryer at a temperature of 60° C. 1.3 g (79% of theoretical) of a colourless, crystalline product were obtained, Rf 0.47 (El A). IR (KBr): 1679.9 cm−1 (C═O) MS: M+=574/576/578 (Br2)

Provenance & Evidence