反応 #3196

反応方程式

potassium t-butoxide

methyl 2-amino-4-chlorobenzoate

dimethyl acetylenedicarboxylate

dimethyl acetylenedicarboxylate

→

dimethyl 7-chloro-4-hydroxyquinoline-2,3-dicarboxylate

収率 28.9%

溶媒

t-butanol

反応条件

後処理

1. 1
   温度was refluxed for 7 hr under a nitrogen atmosphere
2. 2
   温度refluxing another 2.5 hr
3. 3
   その他A precipitate formed
4. 4
   温度the resulting mixture was refluxed for 1.5 hr
5. 5
   温度The mixture was cooled to room temperature
6. 6
   ろ過filtered
7. 7
   その他to separate the solids, which
8. 8
   洗浄were washed with t-butanol and ether
9. 9
   workup.DISSOLUTIONThe solids were dissolved in water
10. 10
    その他to form a precipitate
11. 11
    抽出The resulting mixture was extracted with methylene chloride
12. 12
    洗浄the combined extracts were washed with brine and water
13. 13
    乾燥dried (MgSO4)
14. 14
    ろ過filtered
15. 15
    濃縮concentrated
16. 16
    その他to give a green solid
17. 17
    その他Recrystallization of this material from methanol

実験手順

A stirred mixture of methyl 2-amino-4-chlorobenzoate (2.50 g, 13.5 mM) and dimethyl acetylenedicarboxylate (2.05 g, 14.4 mM) in t-butanol (22 mL) was refluxed for 7 hr under a nitrogen atmosphere. After adding additional dimethyl acetylenedicarboxylate (1.16 g, 8.13 mM) and refluxing another 2.5 hr, the reaction mixture was allowed to cool to room temperature and potassium t-butoxide (1.56 g, 13.9 mM) was added in one portion. A precipitate formed and the resulting mixture was refluxed for 1.5 hr. The mixture was cooled to room temperature and filtered to separate the solids, which were washed with t-butanol and ether. The solids were dissolved in water and acidified with 1N sulfuric acid to form a precipitate. The resulting mixture was extracted with methylene chloride and the combined extracts were washed with brine and water, dried (MgSO4), filtered and concentrated to give a green solid. Recrystallization of this material from methanol provided dimethyl 7-chloro-4-hydroxyquinoline-2,3-dicarboxylate (1.15 g, 28.9%) as an off-white solid, mp 232-233° C.; MS(CI): 296 (M+H).

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