反应详情

DPPA (35.6 ml, 165 mmol) was added to a stirred solution of 2-hydroxy-6-methylpyridine-3-carboxylic acid (16-1; Aldrich; 22.97 g, 165 mmol) and triethylamine (23.0 ml, 165 mmol) in dry dioxane (300 ml) and the resulting solution was heated to reflux. After 16 h more triethylamine (23.0 ml, 165 mmol) and benzyl alcohol (17.1 ml, 165 mmol) were added and the solution was refluxed for a further 24 h. The reaction was concentrated in vacuo to remove most of the volatiles. The residue was partitioned between methylene chloride (500 ml) and brine (500 ml), acidified to pH 1 with 1 M HCl (165 ml). The aqueous layer was extracted methylene chloride (two times) and the combined organic layers were washed with sodium hydrogen carbonate solution and brine, dried (Na2SO4) and evaporated in vacuo to a brown solid. This was recrystallized from methanol, to give the title compound 16-2 as a tan solid: 1H NMR (300 MHz, CDCl3) δ 2.29 (s, 3H, CH3), 5.20 (s, 2H, PhCH2), 6.06 (d, J=7.6 Hz, pyridinone-5-H), 7.32-7.43 (m, 5H, Ph), 7.67 (br s, 1H, CbzNH), 8.03 (br d, pyridinone-4-H).

1. temperaturethe resulting solution was heated to reflux
2. temperaturethe solution was refluxed for a further 24 h
3. concentrationThe reaction was concentrated in vacuo
4. customto remove most of the volatiles
5. customThe residue was partitioned between methylene chloride (500 ml) and brine (500 ml)
6. extractionThe aqueous layer was extracted methylene chloride (two times)
7. washthe combined organic layers were washed with sodium hydrogen carbonate solution and brine
8. dry with materialdried (Na2SO4)
9. customevaporated in vacuo to a brown solid
10. customThis was recrystallized from methanol