Hydrochloric Acid → 2-Chloro-8-(1-hydroxaminoethyl)phenoxathiin

Participants

Reaction Steps

To a suspension of 2-chloro-8-(1-hydroximinoethyl)phenoxathiin (C.A. 66, 2519a, 1967) (425 mg, 1.456 mmol) in ethanol (12 mL) and THF (5 mL) at room temperature there was added pyridine-borane (271 mg, 0.3 mL, 2.92 mmol) and 4M ethanolic HCl (1.1 mL, 4.4 mmole); the mixture was stirred at room temperature overnight, there was added more pyridine-borane (0.35 mL) and 4M ethanolic HCl (2 mL) and stirring was continued for 2 hours. The solvents were evaporated, the residue diluted with water and ethyl acetate and basified with 1N aqueous NaOH. From the organic phase a crude product was obtained which was chromatographed on silica gel, eluting with a 1:1 mixture of ethyl acetate-hexane, to afford the title product (344 mg) as a white solid, m.p.: 103°-105° C.

Provenance & Evidence