Triethylamine → tert-butyl (5-bromo-3-(3-(4-(((tert-butoxycarbonyl)(tetrahydro-2H-pyran-4-yl)amino)methyl)phenyl)isoxazol-5-yl)pyrazin-2-yl)(tert-butoxycarbonyl)carbamate

Participants

Reaction Conditions

Reaction Steps

A solution of tert-butyl 4-(chloro(hydroxyimino)methyl)benzyl(tetrahydro-2H-pyran-4-yl)carbamate (A-4-i) (1.60 kg, 4.34 mol) and tert-butyl N-(5-bromo-3-ethynylpyrazin-2-yl)-N-tert-butoxycarbonylcarbamate (Compound A-4-ii) (1.73 kg, 4.34 mol) in CH2Cl2 (12.8 L) is stirred at 20° C. Et3N (483 g, 665 mL; 4.77 mol) is added and the reaction temperature maintained below 30° C. The suspension stirred at 20° C. to complete the reaction then diluted with water (8.0 L) and agitated. The phases are separated and the organic phase is washed with water (8.0 L) and then concentrated. i-PrOAc (1.6 L) is added and the mixture and heated at 50° C. Heptane (4.0 L) was slowly added then the suspension is allowed to cool to ambient temperature and stirred overnight. Additional heptane (7.2 L) is added to the suspension and it is stirred for 1 h. The solid is collected by filtration. The filter-cake is washed with heptane (2×1.6 L) and dried to afford tert-butyl (5-bromo-3-(3-(4-(((tert-butoxycarbonyl)(tetrahydro-2H-pyran-4-yl)amino)methyl)phenyl)isoxazol-5-yl)pyrazin-2-yl)(tert-butoxycarbonyl)carbamate (A-5) (2.478 kg; 78%, 97.8 area % purity by HPLC) as a fine, tan powder. 1H NMR (400 MHz, CDCl3) δ 8.60 (s, 1H), 7.78 (d, J=8.3 Hz, 2H), 7.31 (m, 3H), 4.42 (br m, 3H), 4.03-3.82 (m, 2H), 3.38 (br s, 2H), 1.60 (m, 4H), 1.36 (s, 27H).

Provenance & Evidence