Nsc21187 synthesis

Yield:87932-49-8 79%

Reaction Conditions:

with boron tribromide in dichloromethane at 0; for 2 h;Inert atmosphere;

Steps:

46.i

Synthesis 464-(3-Chloro-4,5-bis(cyclopentyloxy)benzamido)benzoic acid (AAA-044)Step (i): 3-Chloro-4,5-dihydroxybenzoic acid (2)1Tribromoborane (7.86 mL, 82 mmol) was added dropwise to a stirring mixture of 3-chloro- 4-hydroxy-5-methoxybenzoic acid (1) (6.61 g, 32.6 mmol) in DC (50 mL) under nitrogen at 0°C. The resulting orange mixture was stirred at the same temperature for 2 h then poured portionwise onto ice / brine (250 mL). The aqueous phase was extracted with EtOAc (2 x 150 mL) and the combined organic extracts were dried over MgS0₄ and filtered. The solvent was removed in vacuo to give 3-chloro-4,5-dihydroxybenzoic acid (2) (5.11 g, 79%): m/z 187 [M-H]^' (ES^"); ¹H NMR (400 MHz, DMSO-d₆) δ: 12.69 (1 H, br s), 10.14 (2H, br s), 7.35 (1 H, d), 7.32 (1 H, d).

References:

WO2011/27106,2011,A1 Location in patent:Page/Page column 106-107