Ethyl 5-methoxy-1-phenyl-1H-pyrazole-4-carboxylate → 5-Methoxy-1-phenyl-1H-pyrazole-4-carboxylic acid

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Reaction Steps

The ester prepared as described in (a) above (390 mg, 1.58 mmol) in lN sodium hydroxide (10 ml) was refluxed for 3 hours under nitrogen and then allowed to cool and the solution was washed with ethyl acetate. The aqueous layer was then acidified to pH 2(HCl) whereupon the title compound precipitated out and was filtered and washed with water followed by drying under vacuum (268 mg, 78%), νmax (Nujol) 1680, 1595, 1560 cm-1 δ (D6 -Acetone) 4.24 (3H,s,--OCH3),7.74 (5H,m, phenyl protons), 8.06 (1H,s,C5 pyrazole proton), Found M+ ; 218.0684, C11H10N2O3Requires M,218.0689.

Provenance & Evidence