ChemicalBook CAS DataBase List 2-Fluoropyridine-5-boronic acid pinacol ester

2-Fluoropyridine-5-boronic acid pinacol ester synthesis

5synthesis methods

Product Name:2-Fluoropyridine-5-boronic acid pinacol ester
CAS Number:444120-95-0
Molecular formula:C11H15BFNO2
Molecular Weight:223.05

766-11-0

73183-34-3

2-Fluoropyridine-5-boronic acid pinacol ester

444120-95-0

General procedure for the synthesis of 2-fluoro-5-bromopyridine and pinacol ester of bisboronic acid from 2-fluoro-5-bromopyridine and pinacol ester of bisboronic acid: under nitrogen protection, Pd(dppf)Cl2 (4.16 g, 5.68 mmol) was added in a single step to a solution containing 5-bromo-2-fluoro-pyridine (10 g, 56.82 mmol), pinacol ester of bisboronic acid (21.64 g, 85.23 mmol) and potassium acetate (16.73 g, 170.46 mmol) in a solution of dioxane (100 mL). The mixture was stirred at room temperature for 10 minutes and then heated to reflux for 6 hours. Upon completion of the reaction, the solvent was removed by direct evaporation and the residue was purified by flash silica gel column chromatography to afford the target product 2-fluoropyridine-5-boronic acid pinacol ester (10.5 g, 82.85% yield). The structure of the product was confirmed by 1H NMR (400 MHz, chloroform-d): δ 8.59 (s, 1H), 8.15 (dt, J = 1.76, 8.41 Hz, 1H), 6.91 (dd, J = 2.26, 8.28 Hz, 1H), 1.35 (s, 12H).

766-11-0 Synthesis

766-11-0
462 suppliers
$6.00/5g

73183-34-3
588 suppliers
$6.00/5g

444120-95-0
183 suppliers
$6.00/250mg

Yield:444120-95-0 90%

Reaction Conditions:

with tetrakis(triphenylphosphine) palladium⁽⁰⁾;potassium acetate in 1,4-dioxane;water at 100; for 12 h;Inert atmosphere;

Steps:

1 Synthesis of intermediate E2-1

Add 2-fluoro-5-bromopyridine (17.6g) to a 1000ml three-necked flask, bis(pinacolato)diboron (38.1g),And potassium acetate (50.0g),Pd (PPh3) 4 (5.7g),Add 600/100 ml of Dioxane / H2O solvent and stir at 100 ° C for 12h under a nitrogen atmosphere.After cooling, the filtrate was filtered off with suction, the solvent was spin-dried and extracted with dichloromethane.Column chromatography was then used to obtain intermediate E2-1 in 90% yield.MS (ASAP): 223.05.

References:

CN110759910,2020,A Location in patent:Paragraph 0185-0187

76-09-5 Synthesis