Hydroxyamine hydrochloride → 2-chloro-6-[(E)-C-(2,5-difluorophenyl)-N-hydroxycarbonimidoyl]-3-methoxyphenol

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Reaction Steps

A mixture of 28 g of 3-chloro-2',5'-difluoro-2-hydroxy-4-methoxybenzophenone and 26 g of hydroxylamine HCl in 250 ml pyridine is refluxed for three hours. Pyridine is evaporated and the residue partitioned between ethyl acetate and 5% HCl. The ethyl acetate extract is washed with water, dried over Na2SO4 and evaporated to give a solid product as a mixture of isomers. The solid is heated at 200°-210° C. for approximately 30-45 minutes and recrystallized from toluene giving E-3-chloro-2',5'-difluoro-2-hydroxy4-methoxybenzophenone oxime, mp 209°-210° C.

Provenance & Evidence