Yield: 93%

Reaction Conditions:

in methanol at 20;

Steps:

56.A Step A: Methyl 4-bromo-3-chlorobenzoate:
To a suspension of 4-bromo-3- chlorobenzoic acid (1 .2 g; 5.18 mmol) in MeOH (HPLC grade; 10 ml) chlorotrimethylsilane (2 ml) was added and the resulting mixture was stirred over a weekend at room temperature. After evaporation of solvents under reduced pressure the residue was diluted to 60 ml with EtOAc, washed with 5% NaHC0₃ (2 x 10 ml), brine (20 ml), dried over anhydrous MgS04, filtered and filtrate evaporated to dryness to give a title compound (1 .2 g; 93%), as creamy solid. ¹H-NMR (CDCI₃) 8.09 (d, 1 H, J = 1 .4 Hz); 7.75 (dd, 1 H, J = 1 .4; 8.3 Hz); 6.68 (d, 1 H), J = 8.3 Hz); 3.91 (s, 3H).

References:

AKAAL PHARMA PTY LTD;GROBELNY, Damian W;GILL, Gurmit S WO2014/63199, 2014, A1 Location in patent:Page/Page column 87