Toluene → 3-(2-Benzothiazolyl)-5-(phenylmethyl)-2-thioxo-4-thiazolidinone

Participants

Reaction Steps

A solution of N-[(2-benzothiazolylamino)thioxomethyl]-DL-phenylalanine methyl ester (1.0 g, 2.69 mmol) and p-toluene sulfonic acid hydrate (0.20 g 1.05 mmol) in toluene (80 mL) was refluxed with a Dean-Stark trap for 36 h. The reaction was cooled to room temperature, solvent removed under reduced pressure, residue taken up in ethyl acetate, washed with saturated sodium bicarbonate and saturated sodium chloride, dried over magnesium sulfate, and concentrated under reduced pressure. The resulting product was recrystallized from ethyl acetate-hexanes to provide 74.9 mg (8% of the titled product: mp 187°-189° C.; IR (KBr, cm-1) 3250, 1766, 1522, 1489; 1H NMR (300 MHz, DMSO-d6) δ 11.00 (s, 1H), 8.18 (d, 1H), 8.02 (d, 1H), 7.08-8.00 (m, 2H), 7.37 (m, 3H), 7.23 (d, 2H), 4.97 (t, 1H), 3.18 (d, 2H); MS (FD) m/e 339(M+); UV (EtOH) 300 nm (ε=7355), 265 nm (ε=19454), 217 nm (ε=26558), 203 nm (ε=31150). Anal. Calcd for C17H13N3OS2 : C, 60.16; H,3.86; N,12.38. Found: C, 60.33; H, 4.14; N, 12.25.

Provenance & Evidence