Water → 1H-Pyrazole-1-carboxylic acid, 4,5-dihydro-5-phenyl-, ethyl ester

Beteiligte Stoffe

Reaktionsschritte

Triethylamine (2.1 g) was added to a solution of 2.92 g 5-phenyl-2-pyrazoline in 50 ml chloroform, and the mixture was stirred with ice cooling. To the resulting solution, was added dropwise 2.17 g ethyl chloroformate, and the mixture was stirred for one hour. After addition of 50 ml water, the mixture was extracted with 50 ml chloroform, the extract was dried, the dried solution was concentrated, and the residue was purified by silica gel chromatography (chloroform/methanol=100/1), giving 2.7 g (yield: 62%) of pure product as oil. NMR (DMSO-d6): 1.21 (3H, t, J=6 Hz), 2.6-3.7 (2H, m), 4.18 (2H, q, J=6 Hz), 5.22 (1H, dd, J=6, 12 Hz), 6.92 (1H, t, J=2 Hz), 7.1-7.5 (5H, m).

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