反应详情

4.99 ml (35.83 mmol) of triethylamine was added to a suspension of 9.29 g (35.83 mmol) of 1,4-dihydro-5-hydroxy-4-oxo-1-(phenylmethyl)-2-pyridineacetic acid, 0.28 g (1.79 mmol) of N-hydroxybenzotriazole, 0.22 g (1.79 mmol) of N-dimethylaminopyridine, 3.62 g (35.83 mmol) of N-aminoimidazolidinone and 8.13 g (39.41 mmol) of dicyclohexylcarbodiimide in 115 ml of dry dimethylformamide. Stirring was continued overnight at room temperature. The precipitated dicyclohexylurea was filtered off, washed with dimethylformamide, and the filtrate was evaporated in vacuo to leave a residue, which became crystalline by stirring with 110 ml of dichloromethane. The precipitate was collected by suction and dried in vacuo. To a suspension of this crude material in 65 ml of dry acetonitrile, 14.0 ml (71.6 mmol) of N-methyl-N-trimethylsilyltrifluoroacetamide was added. After having been stirred for 30 minutes at room temperature, the undissolved dicyclohexylurea was filtered off and the filtrate was evaporated in vacuo. The oily residue was boiled in 70 ml of methanol for 15 minutes and cooled. The precipitate was collected by suction, washed successively with methanol, methanol/ether (1:1) and ether and dried in vacuo. Yield: 8.7 g; sint. 242° C., melting point 260°-265° C. dec.

1. filtrationThe precipitated dicyclohexylurea was filtered off
2. washwashed with dimethylformamide
3. customthe filtrate was evaporated in vacuo
4. customto leave a residue, which
5. customThe precipitate was collected by suction
6. customdried in vacuo
7. additionwas added
8. stirringAfter having been stirred for 30 minutes at room temperature
9. filtrationthe undissolved dicyclohexylurea was filtered off
10. customthe filtrate was evaporated in vacuo
11. waitThe oily residue was boiled in 70 ml of methanol for 15 minutes
12. temperaturecooled
13. customThe precipitate was collected by suction
14. washwashed successively with methanol, methanol/ether (1:1) and ether
15. customdried in vacuo
16. custom242° C., melting point 260°-265° C. dec.