1-(2-METHOXYPHENYL)-5-METHYL-1H-PYRAZOLE-4-CARBOXYLIC ACID synthesis

Yield:241798-56-1 85%

Reaction Conditions:

with sodium hydroxide in methanol;water;

Steps:

13.A 5-Methyl-1-(2-methoxyphenyl)-1H-pyrazole-4-carboxylic acid

EXAMPLE 13A 5-Methyl-1-(2-methoxyphenyl)-1H-pyrazole-4-carboxylic acid To a solution of ethyl 5-methyl-1-(2-methoxyphenyl)-1H-pyrazole-4-carboxylate in 15 ml methanol and 17 ml water was added 20 ml of 1 N sodium hydroxide and the resulting mixture was refluxed overnight under nitrogen. The methanol was removed in vacuo and the aqueous phase was acidified with dilute aqueous hydrochloric acid solution and extracted with 2*70 ml ethyl acetate. The combined ethyl acetate extracts were washed with 70 ml water and 70 ml brine, dried over sodium sulfate and concentrated in vacuo to a white solid (2.14 g, 85% yield). ¹H NMR (CDCl₃) δ2.37 (s, 3H); 3.79 (s, 3H); 7.04 (q, 2H); 7.3 (d, 1H); 7.44 (m, 1H); 8.09 (s, 1H).

References:

US6492401,2002,B1