Triethylamine → 2-Tert-butylbenzoxazole-4-carboxylic acid

HRID 1987965

반응식

HRID 1987965 반응식
Br.[NH2:2][C:3]1[C:11]([OH:12])=[CH:10][CH:9]=[CH:8][C:4]=1[C:5]([OH:7])=[O:6].[C:13](Cl)(=O)[C:14]([CH3:17])([CH3:16])[CH3:15].C(N(CC)CC)C.O.C1(C)C=CC(S(O)(=O)=O)=CC=1>ClCCl.O>[C:14]([C:17]1[O:12][C:11]2[C:3](=[C:4]([C:5]([OH:7])=[O:6])[CH:8]=[CH:9][CH:10]=2)[N:2]=1)([CH3:16])([CH3:15])[CH3:13]

참가 물질

7

반응물 4

HCID 8471TriethylamineHCID 62493Pivaloyl chlorideHCID 521998p-Toluenesulfonic acid monohydrateHCID 668807402-Amino-3-hydroxybenzoic acid hydrobromide

생성물 1

HCID 676559072-Tert-butylbenzoxazole-4-carboxylic acid수율 53.5%

시약·촉매·용매 2

HCID 962Water용매HCID 6344Dichloromethane용매2회

실험 절차

To a mixture of 2-amino-3-hydroxybenzoic acid hydrobromide (0.30 g, 1.28 mmol) and pivaloyl chloride (0.16 mL, 1.28 mmol) in dichloromethane (10 mL) was added triethylamine (0.72 mL, 5.12 mmol) dropwise, then the reaction mixture was stirred at room temperature for 1 h. The reaction mixture was diluted with dichloromethane, and then washed with 2 N HCl. The aqueous layer was extracted with dichloromethane. The combined organic layers were washed with brine, dried (Na2SO4), filtered and concentrated. The crude product was dissolved in toluene (10 mL) and the solution was treated with p-toluenesulfonic acid monohydrate (240 mg, 1.26 mmol). The reaction mixture was then heated to reflux for 1.5 h. The reaction was cooled to room temperature, poured into water and extracted with ethyl acetate. The organic layer was separated then washed with water, brine, dried (Na2SO4), filtered and concentrated. The crude product was purified by column chromatography (silica gel, 9:1 to 3:1 ethyl acetate/methanol) to afford 2-tert-butylbenzoxazole-4-carboxylic acid (0.15 g, 53%) as a white solid: 1H NMR (300 MHz, DMSO-d6) δ 7.75-7.71 (m, 2H), 7.33 (t, J=7.8 Hz, 1H), 1.45 (s, 9H); MS (ESI+) m/z 220 (M+H).

후처리

  1. washwashed with 2 N HCl
  2. extractionThe aqueous layer was extracted with dichloromethane
  3. washThe combined organic layers were washed with brine
  4. dry with materialdried (Na2SO4)
  5. filtrationfiltered
  6. concentrationconcentrated
  7. dissolutionThe crude product was dissolved in toluene (10 mL)
  8. temperatureThe reaction mixture was then heated
  9. temperatureto reflux for 1.5 h
  10. temperatureThe reaction was cooled to room temperature
  11. extractionextracted with ethyl acetate
  12. customThe organic layer was separated
  13. washthen washed with water, brine
  14. dry with materialdried (Na2SO4)
  15. filtrationfiltered
  16. concentrationconcentrated
  17. customThe crude product was purified by column chromatography (silica gel, 9:1 to 3:1 ethyl acetate/methanol)

출처 및 근거

ORD 기록
ord-c93a2285779e443da05fcbd45d4eefab
출처 데이터셋
uspto-grants-2009_06
특허 번호
US07553846B2

연결된 노트

불러오는 중…