3-Chloro-2-hydrazinylpyridine → methyl 1-(3-chloropyridin-2-yl)-5-hydroxy-3-(hydroxymethyl)-4,5-dihydro-1H-pyrazole-5-carboxylate

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Reaktionsschritte

The mixture of methyl (3E)-3-(2,2-dimethyl-1,3-dioxolan-4-ylidene)-2-oxopropanoate (20 g, 0.1 mol) and 2-hydrazino-3-chloropyridine (21.4 g, 0.15 mol) in 150 ml of isopropanol was stirred for 8 hours at RT. The precipitate was filtered off and washed with hexane. This gave 27.6 g (85%) of the product as a pale yellow solid with a m.p. of 113-115° C.

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