Sodium Hypochlorite → Methyl 3-chloro-1-methyl-1H-pyrazole-5-carboxylate

Beteiligte Stoffe

Reaktionsschritte

Methyl 3-chloro-1-methyl-4,5-dihydro-1H-pyrazole-5-carboxylate (21 g, 119 mmol) was added drop wise to sodium hypochlorite (95 ml, 155 mmol) under ice cooling. Then, the ice bath was removed and stirring continued for 72 h. The organic phase was separated, washed with Na2S2O3 (10% aqueous solution) and water, dried over Na2SO4 and the solvent removed under reduced pressure. The resulting oil was purified by distillation (bp 35° C., 0.2 mbar) followed by column chromatography (eluent 80% hexane in EtOAc) to yield 6.0 g (29%) of the title compound. [1H-NMR (DMSO-d6, 360 MHz) δ 6.96 (s, 1H), 6.80 (s, 1H), 4.07 (s, 3H), 3.86 (s, 3H)]

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