Imidazole → HCID 9839780, compound

Participants

Reaction Steps

A solution of 2-hydroxy-9H-xanthene 3 (2.63 g, 13.28 mmole) in DMF (15 ml) was added imidazole (1.36 g, 19.9 mmole), t-butyldimethylsilyl chloride (2.4 g, 15.92 mmole) and DMAP (15 mg) successively at room temperature. The mixture was allowed to stir overnight (16 hrs) and quenched with saturated NaHCO3 solution. The aqueous layer was extracted two times with 10% EtOAc-hexanes. The combined organic layers were washed with water, dried over anhydrous Na2SO4 and concentrated. The light orange oily residue was loaded onto a silica gel plug and eluted with hexanes and then 3% EtOAc-hexanes. The relatively clean fractions of the desired product were pooled and concentrated, yielding the slightly impure 2-tert-butyldimethylsiloxyl-9H-xanthene 4 (3.297 g, 79.5%) as an off-white solid: mp 67-69° C. 1H NMR (CDCl3): delta 7.12-7.19 (2H, m), 6.96-7.01 (2H, m), 6.89 (1H, d, J=8.5 Hz), 6.61-6.67 (2H, m), 3.98 (2H, s), 0.97 (9H, s) and 0.17 (6H, s); 1R (CHCl3): 2960, 2938, 1630, 1587, 1487, 1464, 1251, 1203, 1158, 1120, 976, 892, 868 and 843 cm-1.

Provenance & Evidence