Ethyl Acetoacetate → ST001145

Participants

Reaction Conditions

Reaction Steps

3.05 g of Ethylhydrazine and 6.54 g of Ethyl acetoacetate was dissolved in 10 mL of EtOH and the mixture was heated at 80° C. overnight. The mixture was cooled and partitioned between CHCl3 and water. The organic layer was drier over Na2SO4, concentrated to give 2.43 g of crude 2-ethyl-5-methyl-2,4-dihydro-3H-pyrazol-3-one. 2.35 g of the material was diluted with 4 mL of DMF and 6.2 mL of POCl3 was added dropwise thereto. The mixture was heated at 80° C. overnight, then cooled to room temperature. After addition of ice, the mixture was partitioned between CHCl3 and water. The organic layer was dried over Na2SO4 and concentrated to give 1.46 g of crude 5-chloro-1-ethyl-3-methyl-1H-pyrazole-4-carbaldehyde. 516 mg of the material was diluted with 10 mL of EtOH and 440 mg of HSCH2COOEt and 930 mg of K2CO3 was added thereto. The mixture was stirred at 80° C. overnight. The reaction mixture was cooled and 5 mL of 1N NaOHaq and 5 mL of MeOH was added thereto successively. Then the mixture was heated at 85° C. for 3 hrs. After cooled, the mixture was acidified with 1N HCl (to pH 1.5), then diluted with water. The precipitate was filtered, washed with water and n-hexane, dried in vacuo to afford 214 mg of the targeted compound.

Provenance & Evidence