3-(3,5-DIMETHYL-1H-PYRAZOL-1-YL)PROPANOIC ACID synthesis

Yield:72145-01-8 93.3%

Reaction Conditions:

with water;sodium hydroxide in tetrahydrofuran at 25 - 30; for 1.5 h;

Steps:

40 Example-40: Preparation of 3-(3,5-dimethyl-l //-pyrazol-1 -yl)propanoic acid

To a stirred solution of ethyl 3-(3.5-dimcthyl- 1 //-pyrazol- 1 -yl (propanoatc (4.0 g, 0.020 mole) in tetrahydrofuran (10 mL), aqueous sodium hydroxide solution [sodium hydroxide (1.63 g) in water (10 mL)] was added and stirred for 90 minutes at 25°C to 30°C. The reaction mixture was acidified by dilute hydrochloric acid (30 mL) and distilled to obtain residue. Methanol (10 mL) was added to the residue and distilled to get crude solid. Dichloromethane (25 mL) and methanol (25 mL) were added to the obtained crude solid and stirred for 15 minutes at 25°C to 30°C. The reaction mixture was filtered to remove sodium chloride and the filtrate was distilled to obtain crude solid. Hexane (25 mL) was added to the crude solid and stirred for 30 minutes. The separated solid was filtered, washed with hexane (25 mL) and dried to yield 3-(3,5-dimethyl-l/ -pyrazol-l- yl)propanoic acid as a white solid. Yield: 3.2 g (93.3%). -NMR (400 MHz, DMSO-d₆): d 6.04 (1H, s), 4.21-4.24 (2H, t), 2.81-2.85 (2H, t), 2.29 (3H, s), 2.19 (3H, s). Mass: 169.11 (M⁺ +l). Melting point: 260 6°C

References:

WO2020/58945,2020,A1 Location in patent:Page/Page column 79