反应详情

In a 25 ml. round-bottomed flask equipped with a magnetic bar, water-cooled reflux condenser, and argon-filled balloon, 7-chloroacetamido-2-methylquinoline-5,8-dione (28) (prepared as described in Example 28) (0.529 g., 2 mmol), selenium dioxide (0.255 g., 2.3 mmol), 12 ml of dried, distilled 1,4-dioxane, and 0.25 ml. of water were stirred and slowly heated to reflux over a two-hour period. The reaction was monitored by TLC and allowed to go to completion (29.5 hours). The selenium was allowed to settle, and the supernatant solution was pipetted off and filtered. 1,4-Dioxane (10 ml.) was added to the residue, stirred and refluxed for five minutes. The entire mixture was filtered and the selenium was washed with dichloromethane (10 ml.). All filtrates were combined and stored at 4° C. overnight. Solid precipitate from the chilled mixture was filtered yielding 0.0985 g. of crude product (yield of 18%). This was purified by recrystallization from ethyl acetate/dichloromethane. The original remaining filtrate was diluted with 50 ml of dichloromethane and washed with 3% sodium bicarbonate solution (2×50 ml.). The aqueous layer was then extracted with dichloromethane (2×20 ml.) The organic layers were dried with magnesium sulfate and rotoevaporated to give a dark orange solid. The product was dried under vacuum overnight and 0.2941 g. of product was obtained (yield of 52%, total 70%). This product could be further purified by flash chromatography and recrystallization from ethyl acetate/dichloromethane: mp 190°-192° C.; 1H NMR (CDCl3) δ 4.26 (2H, s, C-7NHCOCH2Cl), 8.04 (1H, s, C-6H), 8.33 (1H, d, J=8.1 Hz, C-3H), 8.62 (1H, d, J=8.1 Hz, C-4H), 9.54 (1H, br. s, C-7NH), 10.28 (1H, s, C-2CHO); IR (KBr) vmax 3310, 3089, 2950, 2852, 1731, 1720, 1678, 1644, 1521, 1118 cm-1 ; EIMS, m/e (relative intensity) 278/280 (M+, 2.7/1, 95), 243 (33), 229 (33), 215 (55), 202 (base), 175 (61), 146 (17); HRMS, m/e for C14H9ClN2 O3 calculated 278.009435, found 278.008764; analysis for C14 H9ClN2O3 calculated C, 51.72; H, 2.53; Cl, 12.72; N, 10.05; Found C, 51.81; H, 2.9; Cl, 12.79; N, 9.86.

1. customround-bottomed flask equipped with a magnetic bar
2. temperaturereflux condenser
3. customof dried
4. distillationdistilled 1,4-dioxane, and 0.25 ml
5. temperatureslowly heated
6. temperatureto reflux over a two-hour period
7. customto go to completion (29.5 hours)
8. filtrationfiltered
9. addition1,4-Dioxane (10 ml.) was added to the residue
10. stirringstirred
11. temperaturerefluxed for five minutes
12. filtrationThe entire mixture was filtered
13. washthe selenium was washed with dichloromethane (10 ml.)
14. filtrationSolid precipitate from the chilled mixture was filtered
15. customyielding 0.0985 g