Hydrochloric Acid → Methyl 2-thioxo-2,3-dihydrobenzoxazole-4-carboxylate

HRID 249823

Reaktionsgleichung

Reaktionsgleichung von HRID 249823
[NH2:1][C:2]1[C:11]([OH:12])=[CH:10][CH:9]=[CH:8][C:3]=1[C:4]([O:6][CH3:7])=[O:5].C(O[C:16]([S-])=[S:17])C.[K+].Cl>N1C=CC=CC=1>[S:17]=[C:16]1[NH:1][C:2]2=[C:3]([C:4]([O:6][CH3:7])=[O:5])[CH:8]=[CH:9][CH:10]=[C:11]2[O:12]1

Komponenten

5

Edukt 3

HCID 313Hydrochloric AcidHCID 205248Anthranilic acid, 3-hydroxy-, methyl esterHCID 2735045Potassium ethylxanthate

Produkt 1

HCID 22272869Methyl 2-thioxo-2,3-dihydrobenzoxazole-4-carboxylateAusbeute 74,3 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 1049PyridineLösungsmittel

Versuchsvorschrift

A mixture of methyl 2-amino-3-hydroxybenzoate from Step A (2.04 g, 12.2 mmol) and potassium O-ethylxanthate (1.37 g, 8.56 mmol) in pyridine (8 mL) was heated to reflux for 2 h, then cooled to room temperature and poured into a mixture of ice-water (45 mL) and conc. HCl (4.8 mL). The resulting precipitate was collected by filtration and washed with water, dried on vacuum to give methyl 2-thioxo-2,3-dihydrobenzoxazole-4-carboxylate (1.33 g, 52%) as a light brown solid: 1H NMR (500 MHz, CDCl3) δ 10.40 (br s, 1H), 7.82 (dd, J 8.0, 1.0 Hz, 1H), 7.49 (dd, J 8.0, 1.0 Hz, 1H), 7.28 (t, J=8.0 Hz, 1H), 4.01 (s, 3H); MS (ESI+) m/z 210 (M+H).

Aufarbeitung

  1. temperaturewas heated
  2. temperatureto reflux for 2 h
  3. filtrationThe resulting precipitate was collected by filtration
  4. washwashed with water
  5. customdried on vacuum

Quellen und Nachweise

ORD-Eintrag
ord-bd8e721cb7564a36bd69681269493389
Quelldatensatz
uspto-grants-2011_01
Patentnummer
US07863271B2

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