(E)-2-(HydroxyiMino)-N-phenylacetaMide synthesis

Yield:-

Reaction Conditions:

with sulfuric acid;hydroxylamine hydrochloride in water at 4 - 95;

Steps:

A

As a non-limiting example, isatins and substituted isatins (intermediates set forth in Tables 1,3, 5 and 7) were synthesized by heating a solution of appropriately protected aniline (0.1 moles), chloral hydrate (0.11 moles), hydroxylamine hydrochloride (0.2 moles) in concentrated H2SO4 (12.5 g) and water (700 mL) to 95°C for ten minutes. The solution was then kept at 4°C overnight. The cream colored isonitroso intermediate was filtered off, washed with water and dried. This compound was ground to a fine powder in a mortar and pestle, and added, with stirring, in portions over 30 minutes to concentrated H2SO4 (40 g) maintained at 60-65°C. The mixture was then heated at 95°C for one hour and poured onto ice (300g). The resulting solid was filtered to give the appropriate substituted isatin.

References:

WO2005/80335,2005,A1 Location in patent:Page/Page column 31; 35