Diethyl Malonate → 3-Bromo-2-methyl-5-nitropyridine

Temperature

100 °C

A solution of diethyl malonate (17.6 mL, 0.116 mol) in diethyl ether (250 mL) at ambient temperature was treated with sodium hydride (80% in mineral oil, 3.5 g, 0.116 mol), and the mixture was stirred for 1 hour. Then 3-bromo-2-chloro-5-nitropyridine (25 g, 105 mmol; prepared from 2-hydroxy-5-nitropyridine according to the procedure of V. Koch and S. Schnatterer, Synthesis 1990, 499-501) was added in portions over 5 minutes. After the mixture had stirred for 1 hour, the solvent was evaporated, and the residue was heated at 100° C. for 1 hour. After the mixture had cooled, 12 N H2SO4 was added, and the mixture was heated at reflux for about 16 hours. The mixture was allowed to cool to ambient temperature, then further cooled as it was treated with 50% NaOH to give an alkaline pH. The resulting solution was extracted with CHCl3 (3×), and the organic extracts were washed with H2O, dried (MgSO4) and evaporated to afford 17.1 g of the title compound as a red oil: 1H NMR (CDCl3, 300 MHz) δ2.81 (s, 3H), 8.61 (d, J=2 Hz, 1H), 9.26 (d, J=2 Hz, 1H).

1. customSchnatterer, Synthesis 1990, 499-501)
2. additionwas added in portions over 5 minutes
3. stirringAfter the mixture had stirred for 1 hour
4. customthe solvent was evaporated
5. temperatureAfter the mixture had cooled
6. addition12 N H2SO4 was added
7. temperaturethe mixture was heated
8. temperatureat reflux for about 16 hours
9. temperatureto cool to ambient temperature
10. temperaturefurther cooled as it
11. additionwas treated with 50% NaOH
12. customto give an alkaline pH
13. extractionThe resulting solution was extracted with CHCl3 (3×)
14. washthe organic extracts were washed with H2O
15. dry with materialdried (MgSO4)
16. customevaporated

ORD record

ord-cf6f60220fc74363b59d59e2376c90d4

Source dataset

uspto-grants-2002_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06403575B1