Trifluoroacetic acid → HCID 131728813, compound

Participants

Reaction Steps

To a stirred solution of 1,1-dimethylethyl 3-methyl-2-oxo-4-imidazolidinecarboxylate (801 mg, 4.00 mmol) (prepared as described in step (iii) of Example 13, starting from (4S)-2-oxo-3-{[(phenylmethyl)oxy]carbonyl}-4-imidazolidinecarboxylic acid) and 5-bromo-1-methylimidazole (644 mg, 4.00 mmol) in 1,4-dioxane (30 ml) was added potassium phosphate (4246 mg, 20.00 mmol), trans-N,N-dimethylcyclohexane-1,2-diamine (0.631 ml, 4.00 mmol) and copper(I) iodide (762 mg, 4.00 mmol) and the mixture stirred at reflux overnight. The reaction mixture was diluted with dichloromethane and filtered through celite. The filter pad was washed with dichloromethane and the filtrate was reduced under vacuum. The residue was re-dissolved in dichloromethane, washed with 0.880 ammonia (×2), water then brine and passed through a hydrophobic frit and the solution was concentrated under vacuum. The residue was purified by Flashmaster automated silica gel chromatography eluting with 0-10% methanol in dichloromethane to give 1,1-dimethylethyl 3-methyl-1-(1-methyl-1H-imidazol-5-yl)-2-oxo-4-imidazolidinecarboxylate (393 mg, 32.6% yield). LC/MS [M+H]+=281. (ii) Trifluoroacetic acid (2 ml) was added to a solution of 1,1-dimethylethyl (4S)-3-methyl-1-(1-methyl-1H-imidazol-5-yl)-2-oxo-4-imidazolidinecarboxylate (390 mg, 1.391 mmol) in dichloromethane (4 ml) and stirred at room temperature for 2 hours, then allowed to stand overnight. The solvent was evaporated and the residue was co-evaporated with toluene and dried under heated vacuum (40° C.) overnight to give 3-methyl-1-(1-methyl-1H-imidazol-5-yl)-2-oxo-4-imidazolidinecarboxylic acid TFA salt (assume ˜1.4 mmol) which was used which was used in the next step. LC/MS [M+H]+=225.

Provenance & Evidence