Reaktion #57965

Reaktionsgleichung

2-bromo-4-[({[(1E)-(4-tert-butylphenyl)methylidene]amino}oxy)methyl]benzoic acid methyl ester

sodium hydroxide

→

2-bromo-4-[({[(1E)-(4-tert-butylphenyl)methylidene]amino}oxy)methyl]benzoic acid

Ausbeute 94.0%

Lösungsmittel

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThis mixture was heated
2. 2
   Temperaturto reflux for 3 hours
3. 3
   EinengenThe mixture was concentrated to approximately ¼ volume
4. 4
   Sonstigepartitioned between ethyl acetate and brine
5. 5
   SonstigeThe layers were then separated
6. 6
   ExtraktionThe aqueous layer was extracted with one additional portion of ethyl acetate
7. 7
   Trocknendried over anhydrous magnesium sulfate
8. 8
   Filtrationfiltered
9. 9
   Einengenconcentrated under reduced pressure
10. 10
    workup.DISSOLUTIONThe crude material was dissolved in hot methylene chloride
11. 11
    Sonstigecrystallized out by the addition of room temperature hexanes (60 mL)

Vorschrift

To a solution of 2-bromo-4-[({[(1E)-(4-tert-butylphenyl)methylidene]amino}oxy)methyl]benzoic acid methyl ester (0.43 g, 1.07 mmol), in 10/5/3 tetrahydrofuran/ethanol/water (24 mL) was added 2.5 M sodium hydroxide solution (4 mL). This mixture was heated to reflux for 3 hours and then allowed to cool back to room temperature. The mixture was concentrated to approximately ¼ volume and partitioned between ethyl acetate and brine. The aqueous layer was acidified to approximately pH 1 using 1 N hydrochloric acid. The layers were then separated. The aqueous layer was extracted with one additional portion of ethyl acetate. The organics were combined, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The crude material was dissolved in hot methylene chloride and crystallized out by the addition of room temperature hexanes (60 mL), and allowing the mixture to sit for 2 hours to give 2-bromo-4-[({[(1E)-(4-tert-butylphenyl)methylidene]amino}oxy)methyl]benzoic acid (0.39 g, 94%) as a white solid. mp=162-163° C. 1H NMR (500 MHz, DMSO-d6); δ 13.35 (bs, 1H), 8.31 (s, 1H), 7.74 (d, 1H), 7.71 (s, 1H), 7.52 (d, 2H), 7.46 (d, 1H), 7.42 (d, 2H), 5.19 (s, 2H), 1.26 (s, 9H). Mass spec (MW 390.28); (ES+) m/z 390.0, (ES−) m/z 388.3. Elemental analysis; Calculated for C19H20BrNO3: C, 58.47; H, 5.17; N, 3.59. Found: C, 57.99; H, 5.03; N, 3.41.

Quelle