Reaktion #3198

Reaktionsgleichung

methyl 2-amino-6-chlorobenzoate

dimethyl acetylenedicarboxylate

potassium t-butoxide

→

dimethyl 5-chloro-4-hydroxyquinoline-2,3-dicarboxylate

Ausbeute 80.4%

Lösungsmittel

t-butanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeformed
2. 2
   TemperaturAfter refluxing this mixture for 1.5 hr
3. 3
   Temperaturit was cooled to room temperature
4. 4
   Filtrationfiltered
5. 5
   Sonstigeto separate the solids
6. 6
   workup.DISSOLUTIONThe solids were dissolved in rarer and the resulting solution
7. 7
   Sonstigeto form a precipitate
8. 8
   FiltrationThe mixture was filtered
9. 9
   Waschenthe collected solids were washed with water and air
10. 10
    Sonstigedried

Vorschrift

A solution of methyl 2-amino-6-chlorobenzoate (3.00 g, 16.2 mM) and dimethyl acetylenedicarboxylate (2.64 g, 18.6 mM) in t-butanol (25 mL) was refluxed under a nitrogen atmosphere for 18 hr. The reaction mixture was cooled to room temperature and potassium t-butoxide (2.09 g, 18.6 mM) was added in one portion whereupon a precipitate formed. After refluxing this mixture for 1.5 hr, it was cooled to room temperature and filtered to separate the solids. The solids were dissolved in rarer and the resulting solution acidified with 1N H2SO4 to form a precipitate. The mixture was filtered and the collected solids were washed with water and air dried to give dimethyl 5-chloro-4-hydroxyquinoline-2,3-dicarboxylate (3.84 g, 80.2%) as a tan solid. An 0.25 g portion of this material was recrystallized from ethyl acetate to provide an analytical sample (0.152 g) of the title compound as an off-white solid, mp 174°-176° C.; MS(CI): 296 (M+H). Analysis for C13H10ClNO5.0.01 H2O: Calculated: C, 52.78; H, 3.41; N, 4.73 Found: C, 52.39; H, 3.38; N, 4.67

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