Nsc21187 synthesis
- Product Name:Nsc21187
- CAS Number:87932-49-8
- Molecular formula:C7H5ClO4
- Molecular Weight:188.57
62936-23-6
87932-49-8
General procedure for the synthesis of 3-chloro-4,5-dihydroxybenzoic acid from 3-chloro-4-hydroxy-5-methoxybenzoic acid: Step (i): tribromoborane (7.86 mL, 82 mmol) was added dropwise to a stirred solution of 3-chloro-4-hydroxy-5-methoxybenzoic acid (6.61 g, 32.6 mmol) in dichloromethane (50 mL) under nitrogen protection. The reaction mixture was continued to be stirred at 0 °C for 2 h and subsequently poured in batches into ice/brine (250 mL). The aqueous phase was extracted with ethyl acetate (2 x 150 mL) and the combined organic phases were dried over magnesium sulfate and filtered. The solvent was removed by concentration under reduced pressure to give 3-chloro-4,5-dihydroxybenzoic acid (5.11 g, 79% yield). Mass spectrum (electrospray ionization, negative mode) m/z 187 [M-H]? ; 1H NMR (400 MHz, DMSO-d?) δ: 12.69 (1H, broad single peak), 10.14 (2H, broad single peak), 7.35 (1H, double peak), 7.32 (1H, double peak).
62936-23-6
89 suppliers
$60.00/500mg
87932-49-8
39 suppliers
$327.00/1g
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