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

HRID 2044025Notes

Reaction equation

CC1(C)O/[C:5](=[CH:7]/[C:8](=[O:14])[C:9]([O:11][CH2:12][CH3:13])=[O:10])/[CH2:4][O:3]1.[NH:16]([C:18]1[C:23]([Cl:24])=[CH:22][CH:21]=[CH:20][N:19]=1)[NH2:17]>C(O)C>[Cl:24][C:23]1[C:18]([N:16]2[C:8]([OH:14])([C:9]([O:11][CH2:12][CH3:13])=[O:10])[CH2:7][C:5]([CH2:4][OH:3])=[N:17]2)=[N:19][CH:20]=[CH:21][CH:22]=1

Participants

Conditions

Temperature: 35 °C

Procedure

The mixture of ethyl (3E)-3-(2,2-dimethyl-1,3-dioxolan-4-ylidene)-2-oxopropanoate (21.4 g, 0.1 mol) and 2-hydrazino-3-chloropyridine (14.3 g, 0.1 mol) in 50 ml of ethanol was stirred for 18 hours at 35° C. Ethanol was removed in vacuo and the residue was taken up in 100 ml of methyl (tert)-butyl ether. The organic phase was washed once with 50 ml of 1% strength HCl and concentrated by evaporation. This gave 26.2 g (86% yield) of the product as a viscous oil with a purity (HPLC) of 97%.

Workup

customEthanol was removed in vacuo
washThe organic phase was washed once with 50 ml of 1% strength HCl
concentrationconcentrated by evaporation

Sources & evidence

ORD record: ord-d7dd7a4e0a394598bd1de6cbc20cd01f
Source dataset: uspto-grants-2013_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08586753B2

Reaction notes

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