N-Boc-[tert-butyl (3-chloropyrazin-2-yl)carbamate] synthesis

Yield:1400820-06-5 90%

Reaction Conditions:

with dmap in dichloromethane;Heating;

Steps:

tert-Butyl N-(3-chloropyrazin-2-yl)-N-[(2-methylpropan-2-yl)oxycarbonyl]-carbamate

The di-tert-butyl dicarbonate (3.90 mL, 16.98 mmol) was added to a stirred mixture of 3-chloropyrazin-2-amine (1 g, 7.72 mmol) and DMAP (0.189 g, 1.54 mmol) in CH₂Cl₂ (20 mL). The resulting mixture was stirred at 20 °C overnight. A saturated aqueous solution of NaHCO₃ was added, the organic phase was separated, washed with brine, dried over MgSO₄ and concentrated. The crude product was purified by flash chromatography on silica gel eluting with 0 to 10% ethyl acetate in dichloromethane. The solvent was evaporated to dryness to afford tert-butyl N-(3-chloropyrazin-2-yl)-N-[(2-methylpropan-2-yl)oxycarbonyl]carbamate (10, 2.300 g, 90 %) as a white solid: LCMS (t_R = 1.30 min., purity = 99%), ESI⁺ m/z, no ion detected; ¹H-NMR (DMSO-d₆) d (ppm) 8.70 (d, J = 2.5 Hz, 1H), 8.62 (d, J = 2.5 Hz, 1H), 1.37 (s, 18H).

References:

Delouvrié, Bénédicte;Germain, Hervé;Harris, Craig S.;Lamorlette, Maryannick;Lebraud, Honorine;Nguyen, Ha Thi Hoang;Noisier, Anais;Ouvry, Gilles [Tetrahedron Letters,2012,vol. 53,# 40,p. 5380 - 5384] Location in patent:supporting information