3,3-DIBROMO-5-CHLORO-1,3-DIHYDROINDOL-2-ONE synthesis

Yield:-

Reaction Conditions:

with pyridinium hydrobromide perbromide in tert-butyl alcohol;

Steps:

1 3,3-Dibromo-5-chloroindol-2(3H)-one

EXAMPLE 1 3,3-Dibromo-5-chloroindol-2(3H)-one To a solution of 5-chloroindole (1.00 g) in t-butanol (65 ml) was added portionwise over 0.5 hr 6.9 g of pyridinium bromide perbromide. The reaction mixture was stirred at room temperature for 2 hours after which TLC analysis (1:1 ethyl acetate/hexane) indicated complete conversion of starting material to several products. The reaction mixture was diluted with ethyl acetate (400 ml) and H₂ O (400 ml). The organic layer was separated and the aqueous layer extracted with ethyl acetate (300 ml). The combined organic extracts were washed with H₂ O (2*400 ml) and brine, dried (Na₂ SO₄) and concentrated in vacuo to a yellow-green oil. Purification on a silica gel column eluted with 40% ethyl acetate/hexane afforded the more polar product (3,3-dibromo-5-chlorooxindole) as a brown solid (1.26 g, 60%).

References:

US4761485,1988,A