Trifluoroacetic acid → HCID 131728814, compound

Participants

Reaction Steps

To a solution of 1,1-dimethylethyl 3-methyl-2-oxo-4-imidazolidinecarboxylate (400 mg, 1.998 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-2-fluoropyridine (352 mg, 1.998 mmol) in 1,4-dioxane (20 ml) was added trans-N,N-dimethylcyclohexane-1,2-diamine (0.062 ml, 0.400 mmol), potassium phosphate (1272 mg, 5.99 mmol) and copper(I) iodide (38.0 mg, 0.200 mmol) and the reaction mixture was heated at reflux under argon overnight. The reaction mixture was allowed to cool and the solvent was evaporated. The residue was partitioned between dichloromethane and water. The organic layer was separated and washed with water (˜50 ml) containing 0.880 ammonia solution (˜5 ml), then brine and passed through a hydrophobic frit and the organic layer was reduced under vacuum. The residue was purified by SP4 automated silica gel chromatography eluting with 10-80% ethyl acetate in isohexane to give 1,1-dimethylethyl 1-(6-fluoro-3-pyridinyl)-3-methyl-2-oxo-4-imidazolidinecarboxylate (422 mg, 68.7% yield). LC/MS [M+H]+=296. (ii) Trifluoroacetic acid (2 ml) was added to a solution of 1,1-dimethylethyl 1-(6-fluoro-3-pyridinyl)-3-methyl-2-oxo-4-imidazolidinecarboxylate (420 mg, 1.422 mmol) in dichloromethane (5 ml) and the mixture was stirred at room temperature for 36 hours. The reaction mixture was reduced under vacuum and the residue was azeotroped with toluene and dried under heated vacuum to give 1-(6-fluoro-3-pyridinyl)-3-methyl-2-oxo-4-imidazolidinecarboxylic acid TFA salt (assume ˜1.4 mmol) which was used in the next step. LC/MS [M+H]+=240.

Provenance & Evidence