Chemical Properties
Light yellow Cryst
Uses
6-methoxy-3-nitropyridine-2-carbonitrile was synthesised from 2-Chloro-6-methoxy-3-nitropyridine. Reatant in the suzuki and negishi couplings reaction. Also as fine chemical intermediate.
Synthesis
In a 500 mL four-neck flask, THF (120 mL), methanol (3.66 g, 115 mmol, 0.95 equiv) and 2,6-dichloro-3-nitropyridine (23 g, 120 mmol, 1 equiv) were added sequentially. After cooling the reaction system to 0 °C, 60% sodium hydride (6.8 g, 170 mmol, 1.7 equiv) was slowly added. The reaction was kept at 0 °C and stirred for 30 min, then brought to room temperature and continued stirring for 2 h. The reaction was then stopped at 0 °C. Upon completion of the reaction, the reaction was quenched with deionized water (100 mL) and extracted with ethyl acetate (3 x 150 mL). The organic phases were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to afford the target compound 2-chloro-6-methoxy-3-nitropyridine (12 g, 56% yield).1H NMR (300 MHz, CDCl3) δ: 8.37-8.24 (m, 1H), 7.07-7.05 (m, 1H), 4.15 (s, 3H).
Structure and conformation
2-chloro-6-methoxy-3-nitropyridine ( 2, 6, 3-CMNP) has a planar structure of the Cs point group symmetry. The three Cartesian displacements of the 17 atoms provide 45 internal modes. All 45 fundamental vibrations are active in both IR and Raman. For an N-atomic molecule, 2N-3 of all vibration is in plane and N-3 is out of plane. Thus, for 2-chloro-6-methoxy-3-nitropyridine, 31 of all the 45 vibrations are n-plane and 14 are out-of-plane.
The compound 2, 6, 3-CMNP has only one methoxy group at the 6th position; therefore there will be only one O-CH3 stretching mode. In case of HF/6-31+G (d, p) this O-C stretching vibration is observed at 1041 cm-1 and by the DFT calculations observed at 1069 cm-1. Each CH3 or OCH3 group rise to three C-H valance oscillations (2800-3000 cm-1) and three C-H deformations as suggested by Bellamy.
References
[1] Sharma B, et al. Ab-initio Hartee-Fock and Density functional theory calculations of 2-Chloro-6-methoxy-3-nitropyridine. Arch. Appl. Sci. Res, 2011; 3: 334-344.
