Chemical Properties
White to pale yellow crystalline powder
Uses
Ethyl pyrazole-4-carboxylate is used for the synthesis of isoxazole-4-carboxylic acid derivatives and isoxazole-3,5-dicarboxamides.
Uses
Used for the synthesis of isoxazole-4-carboxylic acid derivatives and isoxazole-3,5-dicarboxamides as herbicides.
Synthesis
The general procedure for the synthesis of ethyl 4-pyrazolecarboxylate from ethyl 2-formyl-3-oxopropanoate was as follows: 6.2 g (193 mmol) of hydrazine was slowly added to a solution of 27.6 g (192 mmol) of (ethoxycarbonyl)malondialdehyde dissolved in 150 mL of ethanol under ice bath cooling conditions. The reaction mixture was stirred at room temperature for 17 hours to complete the reaction. Subsequently, ethanol was removed from the reaction mixture by vacuum distillation. The residue was purified by silica gel column chromatography using a solvent mixture of dichloromethane and ethyl acetate as the unfolding agent, resulting in 19.4 g (72.4% yield) of ethyl 1H-pyrazole-4-carboxylate as yellow crystals.1H-NMR [CDCl3/TMS, δ (ppm)]: 8.08 (2H, s), 5.30 (1H, s), 4.31 ( 2H, q), 1.36 (3H, t).
References
[1] Tetrahedron, 2008, vol. 64, # 33, p. 7745 - 7758
[2] Journal of Heterocyclic Chemistry, 1993, vol. 30, # 4, p. 865 - 872
[3] Patent: EP1364946, 2003, A1. Location in patent: Page/Page column 196
[4] Patent: US2005/256004, 2005, A1. Location in patent: Page/Page column 32
