Triethylamine → Ethyl 5-(N-Boc)aminomethylisoxazole-3-carboxylate

Participants

Reaction Steps

A solution of ethyl chlorooximidoacetate (10 g, 66 mmol) in THF (200 ml) was added dropwise over 3 hours to a mixture of N-(tert-butyloxycarbonyl)propargylamine (20.5 g, 131 mmol) and triethylamine (11.2 ml, 80 mmol) in tetrahyrofuran (100 ml). The mixture was stirred at ambient temperature for 18 hours and then the volatiles were removed by evaporation. The residue was dissolved in DCM and washed with water followed by brine. The organics were separated, dried (MgSO4) and the solvent removed by evaporation. The residue was purified by column chromatography on silica gel eluting with isohexane/diethyl ether (80:20 then 50:50) to give the title compound (10.6 g, 60%). NMR (DMSO): 1.3 (t, 3H), 1.38 (s, 9H), 4.35 (m, 2H), 6.62 (s, 1H), 7.55 (s, 1H); m/z 269 (M−H)—.

Provenance & Evidence