Yield:-

Reaction Conditions:

Stage #1:5-bromo-2,4-difluoronitrobenzene;malonic acid dimethyl ester with sodium hydride in 1,4-dioxane;mineral oil at 11 - 20; for 17.75 h;
Stage #2: with hydrogenchloride;water for 7 h;Reflux;
Stage #3: with iron;acetic acid at 100; for 7 h;

Steps:

20.c Example 20 N-(5-Fluoro-l,3,3-trimeth l-2-oxoindolin-6-yl)isonicotinamide
c) 6-Bromo-5-fluoroindolin-2-one A suspension of (4-bromo-5-fluoro-2-nitrophenyl)-acetic acid/ (2-bromo-5-fluoro-4-nitro- phenyl)-acetic acid (2.6: 1 mixture, 37.3 g, 134 mmol) and iron (30.0 g, 537 mmol) in acetic acid (671 ml) was heated to 100°C for 7 hours and then cooled to room temperature. Remaining elemental iron was removed with a magnetic rod. Ice water (900 ml) was added to the reaction mixture. The precipitate was filtered off, washed four times with water and then suspended in an ice-cold aqueous solution of 25% HC1 (300 ml) and cone. HC1 (50 ml). After stirring for 10 minutes the precipitate was filtered off and washed four times with water. The precipitate was suspended in a mixture of 1 M aqueous Na₂C0₃ (400 ml) solution and 0.1 M NaOH (100 ml) and stirred for 40 minutes. The precipitate was filtered off and washed four times with 0.1 M aqueous NaOH, three times with water and once with diisopropylether to give title compound as light grey solid (20.5 g). MS ESI (m/z): 228.0/ 230.0 [(M-H)^"]. 1H NMR (DMSO-D₆, 400 MHz): (ppm) = 10.47 (bs, 1H), 7.31-7.28 (m, 1H), 7.01-6.99 (m, 1H), 3.49 (s, 2H).

References:

F. HOFFMANN-LA ROCHE AG;HOFFMANN-LA ROCHE INC.;BRUNNER, Daniela;MALBERG, Jessica;SHANKAR, Bavani G.;KOLCZEWSKI, Sabine;LIMBERG, Anja;PRINSSEN, Eric;RIEMER, Claus;STOLL, Theodor WO2014/40969, 2014, A1 Location in patent:Page/Page column 29-30