ethyl 6-cyclopropylpyridine-2-carboxylate synthesis

Yield:1443759-36-1 48%

Reaction Conditions:

with (1,1'-bis(diphenylphosphino)ferrocene)palladium(II) dichloride;potassium phosphate in toluene at 100; for 8 h;Inert atmosphere;

Steps:

1 Step 1 - 6-Cyclopropylpyridine-2-carboxylic acid

To a solution of ethyl 6-bromopyridine-2-carboxylate (CAS 21190-88-5, 4.00 g, 17.3 mmol) in toluene (35 mL) was added cyclopropylboronic acid (3.73 g, 43.4 mmol), K3PO4 (7.38 g, 34.7 mmol) and Pd(dppf)Cl2 (636 mg, 869 umol). Then the mixture was stirred at 100 °C for 8 hrs. On completion, the reaction mixture was filtered through celite, and washed with DCM (20 mL). The filtrate was concentrated in vacuo and he residue was purified by flash silica gel chromatography (PE/EA=3/1) to give the title compound (1.60 g, 48% yield) as yellow oil. LC- MS (ESI⁺) m/z 192.0 (M+H)⁺ ; ¹H NMR (400 MHz, DMSO-d₆) d 7.86 - 7.72 (m, 2H), 7.47 (d, J = 7.2 Hz, 1H), 4.31 (q, J = 7.2 Hz, 2H), 2.24 - 2.09 (m, 1H), 1.31 (t, J = 7.2 Hz, 3H), 1.04 - 0.87 (m, 4H).

References:

WO2020/264499,2020,A1 Location in patent:Paragraph 00920; 002740-002742