Diethyl Oxalate → Ethyl 3-(2-chloro-5-nitropyridin-4-yl)-2-oxopropanoate

Route A: To a solution of potassium ethoxide (1.46 g, 17.4 mmol) in diethyl ether (80 mL) and ethanol (10 mL) under an argon atmosphere was added diethyl oxalate (2.4 mL, 17.4 mmol) and the mixture stirred at rt for 0.5 h. A solution of 2-chloro-4-methyl-5-nitropyridine (3.0 g, 17.4 mmol) in diethyl ether (20 mL) was added resulting in the formation of a dark green precipitate. The reaction was stirred at rt for 15 h, cooled to 0° C., filtered and washed with cold diethyl ether to give a dark green solid. The solid was dissolved in water (200 mL) and acidified to pH 4 with acetic acid to give an orange precipitate. The solid was collected by filtration and dried to give the title compound. m/z (ES+)=273 [M+H]+. Route B: To a solution of 2-chloro-4-methyl-5-nitropyridine (1.0 g, 5.8 mmol) in diethyl oxalate (4.23 g, 29 mmol) under an argon atmosphere was added 1,8-diazabicyclo[5.4.0]undec-7-ene (0.95 mL, 6.4 mol). The mixture was stirred at rt for 1.5 h then diluted with t-butyl methyl ether (40 mL), water (30 mL) and acetic acid (1 ml). The organic layer was separated, washed with water, dried (MgSO4) and evaporated to dryness. The resultant damp red solid residue was finally dried under high vacuum at 40-50° C. to give the title compound.

1. customThe organic layer was separated
2. washwashed with water
3. dry with materialdried (MgSO4)
4. customevaporated to dryness
5. customThe resultant damp red solid residue was finally dried under high vacuum at 40-50° C.

ORD record

ord-32f383626d944e12b051f96bce68c40d

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08158622B2