2-Hydroxyisobutyric acid → 3-(4-Bromo-3,5-dimethyl-phenyl)-5-(2-hydroxy-prop-2-yl)-[1,2,4]oxadiazole

Participants

Reaction Steps

2-(Benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU; 0.55 g) is added to a solution of 2-hydroxy-isobutyric acid (0.18 g) and N,N-diisopropyl-ethylamine (1.4 mL) in N,N-dimethylformamide (5 mL) at room temperature. The solution is stirred at room temperature for 10 min prior to the addition of 4-bromo-N-hydroxy-3,5-dimethyl-benzamidine (0.40 g). The solution is stirred at room temperature for another 10 min and then at 110° C. overnight. After cooling to room temperature, water is added and the resulting mixture is extracted with ethyl acetate. The combined extract is washed with brine, dried (MgSO4), and concentrated. The residue is chromatographed on reversed phase (HPLC; acetonitrile/water/trifluoroacetic acid) to give the title compound. LC (method 11): tR=1.16 min; Mass spectrum (ESI+): m/z=313/315 (Br) [M+H]+.

Provenance & Evidence