1,1'-Carbonyldiimidazole → 4-(3-Chloro-4-fluorophenyl)-3-(4-[(triisopropylsilyl)oxy]methyl-1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazol-5(4H)-one

Participants

Reaction Conditions

Reaction Steps

N-(3-chloro-4-fluorophenyl)-N′-hydroxy-4-[(triisopropylsilyl)oxy]methyl-1,2,5-oxadiazole-3-carboximidamide (2.2 g, 5.0 mmol) was dissolved in anhydrous tetrahydrofuran (THF) (31 mL) followed by addition of N,N-carbonyldiimidazole (980 mg, 6 mmol). The reaction was heated to 70° C. and monitored by LCMS. Another 0.5 eq of N,N-carbonyldiimidazole was added and the reaction was stirred overnight at 70° C. The reaction was cooled and concentrated in vacuo. The crude oil was dissolved in chloroform and loaded onto a 120 g ISCO cartridge, eluted with 25% EtOAc/Hexane. The combined fractions were stripped to dryness to give the desired product as a white solid (1.74 g, 73%). 1H NMR (400 MHz, DMSO-d6) δ: 7.95 (m, 1H), 7.65 (m, 1H), 7.64 (m, 1H), 5.12 (s, 2H), 1.14 (m, 3H), 1.04 (d, J=7.0 Hz, 18H); MF═C20H26ClFN4O4Si; LCMS calculated for C20H27ClFN4O4Si(M+H)+: m/z=469.147.

Provenance & Evidence