Ammonia → Tert-butyl 4-(4-(2-(o-toluidino)-4-carbamoyloxazol-5-yl)phenyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a solution of 2-(o-toluidino)-5-(4-(4-(tert-butoxycarbonyl)piperazin-1-yl)phenyl)oxazole-4-carboxylic acid (0.038, 0.08 mmol) in DCM (0.8 ml) and DMF (0.6 ml) was added hydroxybenzotriazole monohydrate (0.016 g, 0.10 mmol), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (0.024 g, 0.13 mmol) and 0.5M ammonia in dioxane (0.8 m, 0.4 mmol) and the resultant mixture stirred overnight at room temperature. A further portion each of hydroxybenzotriazole monohydrate (0.016 g, 0.10 mmol), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (0.024 g, 0.13 mmol) and 0.5M ammonia in dioxane (0.8 m, 0.4 mmol) was added and the resultant mixture stirred for 5 hours at room temperature, followed by the addition of hydroxybenzotriazole monohydrate (0.008 g, 0.05 mmol), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (0.012 g, 0.065 mmol) and 0.5M ammonia in dioxane (0.4 m, 0.2 mmol) and the reaction mixture was stirred overnight. The solvent was then removed in vacuo and the residue purified by preparative HPLC to afford tert-butyl 4-(4-(2-(o-toluidino)-4-carbamoyloxazol-5-yl)phenyl)piperazine-1-carboxylate (0.012 g, 0.025 mmol, 32%). LCMS (2) Rt: 3.41 min; m/z (ES+) 478.

Provenance & Evidence