反应详情

To a precooled (−10° C.) suspension of 6-amino-2-(pivaloylamino)pyridine (28.00 g, 0.145 mol) in conc. aqueous HCl (150 mL) was added potassium nitrite (14.81 g, 0.174 mol) dissolved in water (8 mL) over a 1.5 h period. The resulting reaction mixture was stirred for 5 h at −10° C. under nirogen, before ajustment of the pH to 9 by addition of conc. aqueous NaOH. The aqueous solution was extracted with ethyl acetate (3×100 mL) and the organic fractions washed with 2M NaOH (3×40 mL). The organic phase was dried (MgSO4), evaporated in vacuo and recrystallised from n-hexane/ethyl acetae to give the desired product (17,70 g (58%) as a white powder (m.p. 86-87° C.). 1H NMR (DMSO-d6): δ 10.08 (s br, 1H), 8.04 (d, 8.1 Hz, 1H), 7.81 (t, 8.1 Hz, 1H), 7.17 (d, 8.1 Hz, 1H), 1.22 (s, 9H). 13C NMR (DMSO-d6): δ 177.4, 152.5, 147.8, 141.4, 119.0, 112.8, 39.4, 26.8. FAB+ MS (m/z): 213.06 M+H+, calc. for C10H13ClN2O+H+ 213.0795.

1. customThe resulting reaction mixture
2. extractionThe aqueous solution was extracted with ethyl acetate (3×100 mL)
3. washthe organic fractions washed with 2M NaOH (3×40 mL)
4. dry with materialThe organic phase was dried (MgSO4)
5. customevaporated in vacuo
6. customrecrystallised from n-hexane/ethyl acetae