Benzoic Acid → 3-(3,5-Dimethoxyphenyl)-2-{4-[4-(2,4-dioxothiazolidin-5-ylidenemethyl)-phenoxy]-phenyl}-acrylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To a stirred suspension of 9 (352 g, 0.82 mol) in anhydrous toluene (2.5 L), 2,4-thiazolidinedione (98.6 g, 0.84 mol), benzoic acid (134 g, 1.10 mol) and piperidine (107.4 g, 1.26 mol) was added sequentially and heated at reflux temperature with continuous removal of water with the help of Dean-Stark apparatus for 5 h. Toluene (1.0 L) was removed from the reaction mixture and cooled overnight at 4° C. Solid separated was filtered and mother liquor was evaporated to dryness under reduced pressure. The residue obtained was re-dissolved in a mixture of MeOH-diethylether (1:1, 3.0 L). On standing overnight at 4° C., the solution yielded more solids. Solid from both the lots were combined and dried overnight in vacuum oven at 40° C. to give 10 as yellow solid (362.5 g, 86%): mp 106-108° C.; mp 225-226° C.; 1H NMR (360 MHz, DMSO-d6): δ 12.53 (br s, 1H), 7.78 (s, 1H), 7.73 (s, 1H), 7.63 (d, J=9.2 Hz, 2H), 7.25 (d, J=9.2 Hz, 2H), 7.13 (overlapped d, J=8.3 Hz, 2H), 7.11 (overlapped d, J=8.6 Hz, 2H), 6.42 (t, J=2.2 Hz, 1H), 6.27 (d, J=2.2 Hz, 2H), 3.73 (s, 3H), and 3.59 (s, 6H); MS (EI) m/z 518[M]+; Anal. (C28H23NO7S) C, H, N.

Provenance & Evidence