Hydrofluoric Acid → HCID 462654, compound

Participants

Reaction Steps

To a stirred solution of the above (silyloxy)amide 22 (52 mg; 0.127 mmol) in 2.0 mL of acetonitrile was added 2.0 mL of a 1:3 solution of 30% aqueous hydrofluoric acid solution in acetonitrile. The resulting orange solution was stirred for 40 minutes in the ice bath then the excess acid was destroyed by the addition of about 10 mL of a 10% aqueous potassium carbonate solution. The reaction mixture was partitioned between 50 mL of ethyl acetate and 20 mL of saturated aqueous sodium chloride. The layers were separated and the aqueous phase was extracted with 50 mL of ethyl acetate. The combined organic phases were washed with 50 mL of saturated aqueous sodium chloride, dried (Na2SO4) and concentrated in vacuo. The residue (35 mg) was chromatographed over 20 g of silica gel (ethyl acetate-hexane, 1:1) to give 24.4 mg (65%) of the benzamide as an orange oil. 1H NMR (CD3OD; spectrum shows amide bond isomers) δ7.773 (dd, J=8.0, 1.6 Hz, 1H, ArH), 7.383 (dt, J=8.4, 1.6 Hz, 1H, ArH), 6.925-6.860 (m, 2H, ArH), 6.371 (br s, 2H, C=CH), 4.691 (s, 2H, CH2 ; minor isomer), 4.669 (s, 2H, CH2 ; minor isomer), 4.198 (s, 2H, CH2 ; major isomer), 4.173 (s, 2H, CH2 ; major isomer); 13C NMR (CD3OD; spectrum shows amide bond isomers) δ170.987, 161.079, 136.252, 134.962, 133.294, 129.055, 127.061, 125.984, 120.175, 118.424, 116.816, 64.778 (major isomer), 60.079 (minor isomer), 44.033 (major isomer), 39.112 (minor isomer); MS (LSIMS) m/z=55.0 (100%), 295.1 (M+).

Provenance & Evidence