Pyridine → 3,5-Dimethyl-1-phenyl-1H-pyrazole-4-carboxylic acid ethyl ester

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Reaction Steps

Similar to Example 1, phenyl hydrazine (7.5 mmol, 0.8 g) and 2-acetyl-3-oxo-butyric acid ethyl ester (7.5 mmol, 1.3 g) were mixed in a solution of 50% pyridine in ethanol. The solvents were removed under vacuum and the oil resuspended in chloroform. The resulting suspension was washed with 5% sodium bicarbonate, 5% hydrochloric acid, and then brine. The organic layer was dried over NaSO4, the solids filtered, and the solvents removed under vacuum. The crude material was purified over silica gel to yield the named product as an oil. 1H-NMR (CDCl3, ppm): 1.37 t (3H); 2.51 s (6H); 4.32 q (2H); 7.42 bs (5H).

Provenance & Evidence