2-Nitrobenzenesulfonyl chloride → Diethyl 4-[2-(2-nitro-benzenesulfonylamino)-ethoxy]-pyridine-2,6-dicarboxylate

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Reaction Steps

To a solution of 957 mg of diethyl 4-(2-amino-ethoxy)-pyridine-2,6-dicarboxylate monohydrochloride in 30 ml of DCM and 734 μl of pyridine, precooled to about 5° C., was added 798 mg of 2-nitrobenzenesulfonyl chloride. The mixture was warmed to room temperature and stirred for 2 hours. A further 244 μl of pyridine and 665 mg of 2-nitrobenzenesulfonyl chloride were then added thereto and stirring was continued for 15 hours. The mixture was washed with 25 ml of water and the aqueous phase was extracted 2× with 25 ml of DCM. The organic phases were combined, dried over MgSO4, concentrated under reduced pressure and purified by flash chromatography on silica (Merck EasyVarioPrep 150 g column, Si60 15-40 μm), using a gradient of 0 to 10% EtOAc in DCM. The fractions containing the desired product were combined and concentrated under reduced pressure. 960 mg of diethyl 4-[2-(2-nitro-benzenesulfonylamino)-ethoxy]-pyridine-2,6-dicarboxylate were obtained. 1H NMR (400 MHz, DMSO-d6): 1.35 (t, J=7.2 Hz, 6H); 3.41 (t, J=5.2 Hz, 2H); 4.22 (t, J=5.2 Hz, 2H); 4.39 (q, J=7.2 Hz, 4H); 7.50 (s, 2H); 7.80 (m, 2H); 7.92 (m, 1H); 8.04 (m, 2H); 8.40 (m, 1H). LC/MS (C): tr=3.50 min; [M+H]+: m/z 468.

Provenance & Evidence