1-Hexyne → 3,5-Diethyl-1-(3-hex-1-ynyl-phenyl)-1H-pyrazole-4-carboxylic acid methyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 4.20 g (10.0 mmol) of 1-(3-bromo-phenyl)-3,5-diethyl-1H-pyrazole-4-carboxylic acid methyl ester (intermediate 1C) in 35 ml of piperidine was treated with 0.19 g (1.0 mmol) of copper(I)iodide and 1.16 g (1.0 mmol) of tetrakis-(triphenylphosphine)-palladium. The reaction mixture was warmed up to 60° C. and after 15 min, a solution of 0.82 g=1.00 ml (10.0 mmol) of hex-1-yne in 15 ml of piperidine was added drop by drop during 1 hour. After 30 min, the oil bath temperature was steadily increased to 80° C. The reaction mixture was then stirred at 80° C. for 4 hours, and subsequently cooled down to RT. The solvent was evaporated and the residue poured into crashed ice, acidified with HCl (37%) to pH 1-2 and extracted twice with EtOAc; the organic phases were washed with water, dried over magnesium sulfate, filtered and evaporated. The residue was purified by flash column chromatography (n-heptane:EtOAc 1:0-9:1) to afford the title compound as light yellow oil. MS: 339.0 (MH+).

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