ChemicalBook CAS DataBase List 4-Nitro-1-phenyl-1H-pyrazole-3-carboxylic acid

4-Nitro-1-phenyl-1H-pyrazole-3-carboxylic acid synthesis

5synthesis methods

Product Name:4-Nitro-1-phenyl-1H-pyrazole-3-carboxylic acid
CAS Number:701917-03-5
Molecular formula:C10H7N3O4
Molecular Weight:233.18

methyl 4-nitro-1-phenyl-1H-pyrazole-3-carboxylate

701917-02-4
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4-Nitro-1-phenyl-1H-pyrazole-3-carboxylic acid

701917-03-5
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Yield:701917-03-5 97%

Reaction Conditions:

Stage #1: 4-nitro-1-phenyl-1H-pyrazole-3-carboxylic acid methyl esterwith potassium hydroxide;water in tetrahydrofuran at 20; for 16 h;
Stage #2: with hydrogenchloride in tetrahydrofuran;water;

Steps:

B

A solution of methyl 4-nitro-l-phenyl-lH-pyrazole-3-carboxylate (78.1g, 315.9 mmol) in THF (600 mL) was treated with 4M potassium hydroxide (79mL, 316 mmol) dropwise and the solution was stirred at ambient temperature for 16 hours. The reaction was evaporated in vacuo and acidified with 6M HCl. After addition of water (500 mL) the solids were filtered off and dried to give 72.1g (97%, 2 steps) of desired compound as a grayish solid. ¹H NMR (CD₃OD) δ 9.37 (bs, IH), 7.88 (m, 2H), 7.59 (m, 2H), 7.44 (m, IH).

References:

WO2007/87129,2007,A2 Location in patent:Page/Page column 60