Ethanol → HCID 178470866, compound

Participants

Reaction Steps

N,N'-Carbonyldiimidazole (Lancaster Synthesis, 908 mg, 5.6 mmol) was added to a pale yellow slurry of (E)-4-[1,3 bis(cyclohexylmethyl)-1,2,3,6-tetrahydro-2,6-dioxo-9H-purin-8-yl]cinnamic acid (from step (d) example 1, 1.962 g, 4.0 mmol) in anhydrous DMF (15 mL)-THF (15 mL) under nitrogen. The slurry was stirred for 3.75 h, during which time it became bright yellow as a gas evolved. Absolute ethanol (460 mL, 8 mmol) was then added, followed by DBU (Aldrich, 837 mL, 5.6 mmol). Addition of the base produced a deep red reaction mixture and caused almost complete dissolution of the acyl imidazole. After stirring for 18 h, the reaction mixture was treated with an additional equivalent of absolute ethanol (230 mL, 4 mmol). The orange solution was stirred for 2.5 h before volatiles were removed at 1Torr. The resulting brown mixture was chromatographed on silica gel, eluting with a gradient from 0-6% methanol in dichloromethane. The title compound eluted in 0-1% methanol in dichloromethane as an off-white solid (1.643 g, 79%). Recrystallization from dichloromethane-hexanes provided a white powder (1.501 g, 72%), m.p. >300° C.; 1H-NMR (DMSO-d6) consistent with structure.

Provenance & Evidence