2-Aminophenol → 2-(2H-Pyrrol-2-ylidene)-2,3-dihydro-1,3-benzoxazole

HRID 6429

Reaktionsgleichung

Reaktionsgleichung von HRID 6429
[NH:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[C:6]([OH:8])=O.[NH2:9][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][C:11]=1O.B(O)(O)O>C1(C)C(C)=CC=CC=1.C(OCC)(=O)C>[NH:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[C:6]1[O:8][C:11]2[CH:12]=[CH:13][CH:14]=[CH:15][C:10]=2[N:9]=1

Komponenten

6

Edukt 3

HCID 58012-AminophenolHCID 7628Boric AcidHCID 12473Pyrrole-2-Carboxylic Acid

Produkt 1

HCID 1356254822-(2H-Pyrrol-2-ylidene)-2,3-dihydro-1,3-benzoxazoleAusbeute 52 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 7237O-XyleneLösungsmittelHCID 8857Ethyl AcetateLösungsmittel

Versuchsvorschrift

2-(Pyrrol-2-yl)benzoxazole was prepared as follows: A mixture of 5.55 g (0.05 mol) of pyrrole-2-carboxylic acid and 5.46 g (0.05 mol) of o-aminophenol and 3.09 g (0.05 mol) boric acid in 50 mL of xylene was heated under reflux for 3 days while removing water which was generated from reaction using a Dean-Stark trap. The cooled reaction mixture was diluted with 100 mL of ethyl acetate, washed with 150 mL of 5% sodium hydroxide solution and then with 150 mL of water. The separated organic layer was dried over anhydrous sodium sulfate. The resulting crude product was purified by column chromatography on silica gel with 20% hexane in chloroform as eluant. The desired product, 2-(pyrrol-2-yl)benzoxazole (4.75 g, 52%), was obtained as a white solid. m.p. 149°-150° C.; 1H NMR (CDCl3) δ6.38-6.40 (m, 1H, ArH), 7.05-7.06 (m, 1H, ArH), 7.11-7.13 (m, 1H, ArH), 7.29-7.36 (m, 2H, 2xArH), 7.53-7.56 (m, 1H, ArH), 7.65-7.69 (m, 1H, ArH), 10.9 (bs, 1H, NH).

Aufarbeitung

  1. custom2-(Pyrrol-2-yl)benzoxazole was prepared
  2. temperaturewas heated
  3. temperatureunder reflux for 3 days
  4. customwhile removing water which
  5. customwas generated from reaction
  6. customThe cooled reaction mixture
  7. washwashed with 150 mL of 5% sodium hydroxide solution
  8. dry with materialThe separated organic layer was dried over anhydrous sodium sulfate
  9. customThe resulting crude product was purified by column chromatography on silica gel with 20% hexane in chloroform as eluant

Quellen und Nachweise

ORD-Eintrag
ord-2288569fc3ee4fffb9e3876b2052db84
Quelldatensatz
uspto-grants-1993_09
Patentnummer
US05248782

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