Pyridine → S-(2,4-dinitrobenzyl) thioacetate

Redistilled thioacetic acid (25.73 cm3, 0.36 mol) and then dry pyridine (19.9 cm3, 0.246 mol) were added to a stirred solution of 2,4-dinitrobenzyl chloride (13.0 g, 60.0 mmol) in dry THF (180 cm3) at room temperature. After 2 h, the products were filtered and the filtrate was concentrated under reduced pressure. The residual solid obtained was dissolved in dichloromethane (300 cm3) and the resulting solution was washed in turn with saturated aqueous sodium hydrogen carbonate (300 cm3), 1.0 mol dm-3 sulfuric acid (200 cm3) and saturated aqueous sodium hydrogen carbonate (200 cm3). The dried (MgSO4) organic layer was evaporated under reduced pressure and the residue was crystallized from ethyl acetate--petroleum ether (b.p. 60°-80° C.) to give S-(2,4-dinitrobenzyl) thioacetate 16b as a pale yellow solid (12.32 g, 80%) (Found: C, 42.3; H, 3.1; N, 10.9. C9H8N2O5S requires: C, 42.2; H, 3.15; N, 10.9%), m.p. 78°-79° C.; δH [CDCl3 ] 2.35 (3 H, s), 4.49 (2 H, s), 7.91. (1 H, d, J 8.5), 8.41 (1 H, dd, J 2.4 and 8.5), 8.88 (1 H, d; J 2.3); δC [CDCl3 ] 30.2, 30.7, 120.7, 127.6, 134.2, 140.6, 147.1, 148.0, 194.7.