Lithium Hexamethyldisilazide → 4-{[(3-bromo-2-chloro-pyridin-4-yl)-(2-chloro-pyridine-4-carbonyl)-amino]-methyl}-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

Lithium bis(trimethylsilyl)amide (1M solution in THF, 3 ml) was added dropwise to a stirred solution of 4-[(3-Bromo-2-chloro-pyridin-4-ylamino)-methyl]-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester (0.53 g) in tetrahydrofuran (20 ml) at −78° C. under N2. The yellow solution was warmed to 0° C. and then 2-chloroisonicotinoyl chloride (50% solution in toluene, 0.95 g) was added. The solution was stirred at 0° C. for 10 min., quenched by addition of aqueous ammonium chloride, extracted with EtOAc, dried (Na2SO4) and concentrated in vacuo. The residue was purified by silica gel chromatography (CH2Cl2 then CH2Cl2/EtOAc 8:2 cyclohexane:ethyl acetate 8:2) to afford 4-{[(3-bromo -2-chloro-pyridin-4-yl)-(2-chloro-pyridine-4-carbonyl)-amino]-methyl }-3,6-dihydro-2H -pyridine-1-carboxylic acid tert-butyl ester (0.63 g), which was identified by its mass and 1H NMR spectra. MS (ES+) 443/445 (MH+—BOC), 484/486 (MH+-isoprene).

Provenance & Evidence