4-Toluenesulfonyl chloride → HCID 178427792, compound

Participants

Reaction Steps

3-(4-nitro-imidazol-1-yl)-cyclobutanol (Preparation 4, Step 1; 4 g, 22 mmol) was treated with Et3N (7.7 mL, 55 mmol) in methylene chloride (150 mL) followed by p-toluenesulfonyl chloride (TsCl) (5 g, 26.4 mmol) and 4-N,N-dimethylaminopyridine (DMAP) (268 mg, 2.2 mmol). The resulting mixture was stirred at room temperature for 24 h. Analysis by thin layer chromatography showed two new spots. The reaction mixture was diluted with methylene chloride and was washed with water (1×) and brine (1×). The organic layer was dried (MgSO4), filtered, and concentrated in vacuo. Purification by silica gel chromatography (1:1 to 2:1 hexanes-ethyl acetate) allowed for separation of the trans and cis diastereomers. The first spot to elute (high Rf) was the trans-isomer, trans-toluene-4-sulfonic acid 3-(4-nitro-imidazol-1-yl)-cyclobutyl ester (2.7 g, 37% yield); 1H NMR (400 MHz, CDCl3) δ 7.79 (s, 1H), 7.77 (m, 2H), 7.44 (d, J=1.7 Hz, 1H), 7.36 (dd, J=0.5, 8.0 Hz, 2H), 5.034 (m, 1H), 4.94 (m, 1H), 2.9 (m, 2H), 2.7 (m, 2H); MS (AP/CI): 338.1 (M+H)+. The second spot to elute was the cis-isomer, cis-toluene-4-sulfonic acid 3-(4-nitro-imidazol-1-yl)-cyclobutyl ester (2.9 g, 39% yield); 1H NMR (400 MHz, CDCl3) δ 7.8 (m, 3H), 7.43 (d, J=1.4 Hz, 1H), 7.36 (dd, J=0.6, 8.5 Hz, 2H), 4.74 (m, 1H), 4.30 (m, 1H), 3.05 (m, 2H), 2.6–2.5 (m, 2H), 2.45 (s, 3H); MS (AP/CI): 338.1 (M+H)+. Relative configurations were determined by the measurement of nuclear Overhauser effects.

Provenance & Evidence