ChemicalBook CAS DataBase List 2,5-DIMETHYL-4-NITRO-2 H-PYRAZOLE-3-CARBOXYLIC ACID

2,5-DIMETHYL-4-NITRO-2 H-PYRAZOLE-3-CARBOXYLIC ACID synthesis

5synthesis methods

Product Name:2,5-DIMETHYL-4-NITRO-2 H-PYRAZOLE-3-CARBOXYLIC ACID
CAS Number:3920-37-4
Molecular formula:C6H7N3O4
Molecular Weight:185.14

5744-56-9 Synthesis

5744-56-9
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2,5-DIMETHYL-4-NITRO-2 H-PYRAZOLE-3-CARBOXYLIC ACID

3920-37-4
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Yield:3920-37-4 96.1%

Reaction Conditions:

with sulfuric acid;HNO₃ at 60; for 4 h;Inert atmosphere;

Steps:

14.1

Example 14; Preparation of (S)-4-(5-chloro-1,3-dimethyl-1H-pyrazolo[4,3-d]pyrimidin-7-yl)-3-ethylmorpholine (n-1) Step 1: Preparation of 1,3-dimethyl-4-nitro-1H-pyrazole-5-carboxylic acid (n-2) To fuming nitric acid (1.26 mL, 29.97 mmol, 2.0 eq.) at 0° C. was slowly added fuming sulfuric acid (9.76 mL, 104.90 mmol, 7.0 eq.) dropwise over 30 minutes. 1,3-Dimethyl-1H-pyrazole-5-carboxylic acid (2.10 g, 14.98 mmol) was then added portion wise, maintaining the internal temperature below 60° C. The reaction mixture was stirred at 60° C. under N₂for 4 h and then cooled to room temperature (RT). The reaction mixture was poured onto ice. Once ice melted the reaction mixture was extracted with EtOAc (3×500 mL). The organic layers were combined and washed with water and brine, dried (Na₂SO₄), filtered and evaporated in vacuo to give the desired compound as a white solid (2.67 g, 96.1%). ¹H NMR (DMSO-d₆, 500 MHz) δ ppm 3.87 (s, 3H), 2.39 (s, 3H); TLC (15% MeOH/DCM): R_f=0.12.

References:

US2011/86840,2011,A1 Location in patent:Page/Page column 36