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149489-04-3

CARBAMIC ACID, (3-BROMO-2-PYRIDINYL)-, 1,1-DIMETHYLETHYL ESTER synthesis

5synthesis methods
13534-99-1 Synthesis
3-Bromo-2-pyridinamine

13534-99-1
366 suppliers
$4.00/1g

24424-99-5 Synthesis
Di-tert-butyl dicarbonate

24424-99-5
863 suppliers
$13.50/25G

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Yield:149489-04-3 63%

Reaction Conditions:

Stage #1: 2-Amino-3-bromopyridine;di-tert-butyl dicarbonatewith dmap;triethylamine in dichloromethane at 20; for 2.5 h;
Stage #2: with methanol;potassium carbonate at 65; for 5 h;

Steps:

A1 Alternative preparation of intermediate 2:

A solution of 2-amino-3-bromopyridine (100 g, 578 mmol) in DCM (700 mL) wastreated with TEA (170 mL, 1219.7 mmol) and DMAP (3.50 g, 5.73 mmol) and asolution of Boc2O (265 g, 1214.22 mmol) in DCM (100 mL) was added over 30 mm.The solution was stirred at room temp for 2 h. The completion of the reaction wasdetermined by TLC (EtOAc 30%, cyclohexane 70%). The mixture was evaporatedunder vacuum and the residue was dissolved in MeOH (1000 mL), treated with K2C03(200 g, 1447.12 mmol) and heated to 65 °C for 5 h. The reaction mixture was filteredand the filtrate was evaporated under vacuum. The residue was partitioned betweenethyl dichloro methane and water and the organic layer was washed with water, 1 Mcitric acid solution, brine, dried over Na2SO4 and filtered. The filtrate was stirred withflash silica gel, filtered and evaporated under vacuum. The residue was triturated withpetroleum ether 40 - 60°C to give 99.7 g of intermediate 2 (63% yield, pinkish solid).

References:

WO2019/8011,2019,A1 Location in patent:Page/Page column 110; 111