[CH3:1][Si:2]([CH3:15])([CH3:14])[CH2:3][CH2:4][O:5][CH2:6][N:7]1[CH:11]=[CH:10][N:9]=[C:8]1[CH:12]=O.[NH2:16]O.FC(F)(F)C(OC(=O)C(F)(F)F)=O>CO>[CH3:1][Si:2]([CH3:15])([CH3:14])[CH2:3][CH2:4][O:5][CH2:6][N:7]1[CH:11]=[CH:10][N:9]=[C:8]1[C:12]#[N:16]To a solution of 1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazole-2-carbaldehyde (1.5 g, 6.6 mmol) in 5 mL of MeOH was added hydroxylamine (0.6 mL, 9.1 mmol, 50% aqueous soln) and the reaction stirred for 10 min at RT and then concentrated. The residue was dissolved in 10 mL of DCM and 5 mL of pyridine and cooled in an ice bath. To this mixture was added trifluoroacetic anhydride (4.2 g, 20 mmol) and the reaction stirred for 8 h at RT. The mixture was concentrated and then dissolved in EtOAc (50 mL) and washed with NaHCO3 (2×50 mL) and brine (50 mL). The organic layer was dried (Na2SO4) and concentrated to give 1.2 g (81%) of a brown oil of sufficient purity to use in the next step. 1H-NMR (CDCl3, 400 MHz): δ 7.28 (s, 2H), 5.48 (s, 2H), 3.56 (m, 2H), 0.96 (m, 2H), 0.00 (s, 9H). Mass spectrum (APCI, m/z): Calcd. for C10H17N3OSi, 224.1 (M+H), found 223.6.
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