邻氨基苯酚 → 2-(2H-Pyrrol-2-ylidene)-2,3-dihydro-1,3-benzoxazole

HRID 6429

反应方程式

HRID 6429 反应方程式
[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

参与物

6

反应物 3

HCID 5801邻氨基苯酚HCID 7628硼酸HCID 12473吡咯-2-羧酸

产物 1

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

试剂、催化剂与溶剂 2

HCID 7237邻二甲苯溶剂HCID 8857乙酸乙酯溶剂

实验过程

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).

后处理

  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

来源与证据

ORD记录
ord-2288569fc3ee4fffb9e3876b2052db84
来源数据集
uspto-grants-1993_09
专利号
US05248782

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