Zur Kenntnis der 3,4,5‐Trioxy‐zimtsäure und über den Mechanismus der Knoevenagelschen Zimtsäure synthese

5‐Benzylidenethiazolidin‐4‐ones as Multitarget Inhibitors of Bacterial Mur Ligases

“…( Z )‐5‐(3,4‐Dihydroxybenzylidene)‐2‐thioxothiazolidin‐4‐one (5 c) : Recrystallization from MeOH gave 5 c as a brown crystalline solid (0.229 g, 60 %): R f =0.45 (CH 2 Cl 2 /MeOH/CH 3 COOH; 9:1:0.1); mp: >300 °C (literature value,35 270–280 °C); 1 H NMR (300 MHz, [D 6 ]DMSO): δ =13.66 (s, 1 H, N H ), 9.93 (s, 1 H, O H ), 9.51 (s, 1 H, O H ), 7.47 (s, 1 H, C H ), 7.02–6.98 (m, 2 H, Ar H (2,6) ), 6.88 ppm (d, 1 H, Ar H (5) ); 13 C NMR (75 MHz, [D 6 ]DMSO): δ =195.4, 169.4, 149.1, 146.0, 132.8, 124.8, 124.3, 120.6, 116.6, 116.4 ppm; IR (KBr): $\tilde \nu $ =3445, 2054, 1677, 1640, 1611, 1584, 1527, 1435, 1288, 1259, 1166, 1117, 968, 906, 844, 758, 615, 556, 510, 484 cm −1 ; MS (ESI+): m/z (%): 254 (100) [ M +H] + ; HRMS (ESI−): m/z [ M −H] − calcd for C 10 H 6 NO 3 S 2 : 251.9789, found: 251.9796.…”