Hydroxyamine hydrochloride → 2-chloro-6-[(E)-C-(2,3-difluorophenyl)-N-hydroxycarbonimidoyl]-3-methoxyphenol

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Reaction Steps

To a solution of 24 g of 3-chloro-2-hydroxy-4-methoxy-2',3'-difluorobenzophenone in 160 ml pyridine, 22 g of hydroxylamine HCl is added. The mixture is refluxed for 2 hours and the pyridine evaporated in vacuo. The residue is partitioned between ethyl acetate and 5% HCl. The ethyl acetate extract is washed with water, dried over Na2SO4 and evaporated to give a pale yellow solid which consists of two isomers. The solid is melted at 205° C. for approximately 13 minutes. The residue is dissolved in hot ethylacetate and then evaporated to dryness giving E-3-chloro-2',3'-difluoro-2-hydroxy-4-methoxybenzophenone oxime, mp 198°-199° C.

Provenance & Evidence