Iodoethane → tert-butyl 4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

1,8-Diazabicyclo[5.4.0]undec-7-ene (76 mL, 511.14 mmol) was added to a suspension of tert-butyl 4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1H-1,2,4-triazol-3-yl)piperidine-1-carboxylate (150 g, 319.46 mmol) in 2-methylTHF (1.2 L). Iodoethane (46 mL, 575.03 mmol) was added and the mixture was stirred for 16 hours at 35° C. Further iodoethane (46 mL, 575.03 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (76 mL, 511.14 mmol) were added and stirring was continued for 24 hours at 35° C. The mixture was poured into water and the insoluble material was isolated by filtration, washed with water and MTBE and dried in vacuo to afford tert-butyl 4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidine-1-carboxylate (116 g, 73.0%) as a yellow solid. The filtrate was extracted with DCM and the organic solution was dried with magnesium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by flash column chromatography on silica using gradient elution (30% MTBE/heptane to 100% MTBE). A second crop of the desired product (12 g, 24.12 mmol, 7.55%), was thus isolated as a yellow solid which was later combined with the first crop: 1H NMR Spectrum: (DMSO-d6) 1.41 (9H, s), 1.44 (9H, s), 1.48 (3H, t), 1.52-1.69 (2H, m), 1.87-2.04 (2H, m), 2.79-3.03 (3H, m), 3.86-4.03 (2H, m), 4.59 (2H, q), 7.89 (2H, s), 8.85 (1H, s); Mass Spectrum [M+H]+=498. THF may also be a suitable solvent for the above reaction.

Provenance & Evidence