4-Chloro-6-hydrazinylpyrimidine → 2-(6-Chloropyrimidin-4-yl)-4-pyridin-3-yl-1,2-dihydro-3H-pyrazol-3-one

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Reaction Steps

At RT, 30.0 g (207.5 mmol) of the compound from Example 7A and 50.3 g (228.3 mmol) of the compound from Example 3A are stirred in 1000 ml of glacial acetic acid for 16 h. For work-up, the solvent is removed on a rotary evaporator, the residue is taken up in ethyl acetate and washed with saturated sodium bicarbonate solution until neutral, and the organic phase is concentrated under reduced pressure. The residue is dissolved in 1000 ml of ethanol, 42.8 ml (41.1 g, 228.3 mmol) of 30% strength methanolic sodium methoxide solution are added and the mixture is stirred at RT for 2 h. The reaction mixture is then adjusted to pH 5 using 1 N hydrochloric acid and stirred for 16 h. The precipitate is filtered off, the filter residue is washed with water and ethanol and the product is dried under reduced pressure.

Provenance & Evidence