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

Participants

Reaction Steps

To a stirred suspension of Compound VI (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 L) was removed from the reaction mixture and the mixture was placed overnight in a 4° C. cold room. Solid separated was filtered off 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 L). Solution on standing overnight at 4° C. yielded more solids. The solid was filtered; both the crops were pooled together and dried overnight in vacuum oven at 40° C. Yield: 362.5 g (86 %). 1H NMR (DMSO-d6): δ 12.53 (br, 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), 7.15 (d, J=4.3 Hz, 2H), 7.12 (d, J=4.3 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).

Provenance & Evidence