反应详情

A solution of 4.54 g (0.022 moles) dicyclohexylcarbodiimide in 25 ml dry of dimethylformamide was added to a stirred suspension of 4.90 g (0.020 moles) of 1,4-dihydro-4-oxo-5-(phenylmethoxy)-2-pyridinecarboxylic acid, 4.50 g (0.022 moles) of 4-methoxybenzyl carbazate, 0.12 g (1.0 mmol) of 4-dimethylamino-pyridine and 0.155 g (1.0 mmol) of 1-hydroxybenzotriazole hydrate in 25 ml of dry dimethylformamide at room temperature and stirring was continued overnight. The precipitate was filtered off and the filtrate was evaporated in vacuo. The residue solidified by stirring with ether and aqueous sodium bicarbonate and the solid was collected, washed with water and finally dried in vacuo. The crude material (8.14 g) was extracted in a soxhlet-apparatus with 800 ml CHCl3 (7 hours). 5.70 g (67%) of pure 1,4-dihydro-4-oxo-5-(phenylmethoxy)-2-pyridinecarboxylic acid, 2-[[(4-methoxyphenyl)methoxy]carbonyl]hydrazide crystallized directly from the cold CHCl3 -extract, and an additional impure amount (1.5 g, 18%) of the title compound could be obtained by evaporation of the CHCl3 -solution in vacuo; melting point 174.5°-178° C.

1. filtrationThe precipitate was filtered off
2. customthe filtrate was evaporated in vacuo
3. stirringby stirring with ether and aqueous sodium bicarbonate
4. customthe solid was collected
5. washwashed with water
6. customfinally dried in vacuo
7. extractionThe crude material (8.14 g) was extracted in a soxhlet-apparatus with 800 ml CHCl3 (7 hours)
8. custom5.70 g (67%) of pure 1,4-dihydro-4-oxo-5-(phenylmethoxy)-2-pyridinecarboxylic acid, 2-[[(4-methoxyphenyl)methoxy]carbonyl]hydrazide crystallized directly from the cold CHCl3 -extract