Dichloromethane → 3-Pyridinol, 6-bromo-, 3-acetate

Participants

Reaction Conditions

Reaction Steps

To 25.6 mL of boron trifluoride etherate (208 mmol, Aldrich) cooled to -15° C. under N2 was added 18 g (104 mmol) of 5-amino-2-bromopyridine from step 128a above dissolved in 35 mL of DME. Then tert-butyl nitrite (14.7 mL, 125 mmol, Aldrich) was added at a rate which kept the temperature below 0° C. DME (65 mL) and methylene chloride (60 mL) were then added. After 10 minutes at -10° C. the mixture was warmed to 5° C. and stirred for 30 min. Pentane (400 mL) was then added to the reaction mixture, the solid was collected by suction filtration, washed with cold ether, air dried, and dissolved in 125 mL acetic anhydride. The resulting solution was heated to 100° C.±5° C. for 1 hour. The solvent was removed in vacuo, and the residue was suspended in saturated aqueous Na2CO3, and extracted with ethyl ether. The ether solution was dried over MgSO4, the solvent was removed in vacuo, and the residue was chromatographed on silica gel, eluting with 100:0 to 60:40 hexane:ethyl acetate to give 13.6 g of the title compound: 1H NMR (CDCl3, 300 MHz) δ 2.35 (s, 3H) 7.37 (dd, 1H), 7.51 (d, 1H), 8.19-8.21 (d, 1H) MS m/z: 216 (M+H)+, 233 (M+NH4)+.

Provenance & Evidence