反応 #6526

反応方程式

pyrrole-2-carboxylic acid

2-aminothiophenol

boric acid

→

2-(pyrrol-2-yl)benzothiazole

収率 14.0%

溶媒

xylene

ethyl acetate

反応条件

後処理

1. 1
   温度was heated
2. 2
   温度under reflux for 3 days
3. 3
   その他while removing water which
4. 4
   その他was generated from reaction
5. 5
   その他the cooled reaction mixture
6. 6
   洗浄washed with 200 mL of 5% sodium hydroxide solution
7. 7
   乾燥The separated organic layer was dried over anhydrous sodium sulfate
8. 8
   その他The resulting crude product was purified by column chromatography on silica gel with 10% ethyl acetate in hexane as eluant

実験手順

A mixture of 5.55 g (50 mmol) of pyrrole-2-carboxylic acid, 6.26 g (50 mmol) of 2-aminothiophenol and 3.09 g (50 mmol) of boric acid in 250 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 200 mL of ethyl acetate, washed with 200 mL of 5% sodium hydroxide solution and then with 200 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 10% ethyl acetate in hexane as eluant. The desired product, 2-(pyrrol-2-yl)benzothiazole (1.40 g, 14%) was obtained as a pale yellow solid. m.p. 150°-151° C.; 1H-NMR (CDCl3) 6.32-6.35 (m, 1H, ArH), 6.87-6.89 (m, 1H, ArH), 6.94-6.96 (m, 1H, ArH), 6.33 (t, 1H, ArH), 6.43 (t, 1H, ArH), 7.84 (d, 1H, ArH), 7.90 (d, 1H, ArH).

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