Using capillary microreactor to synthesize three thiazolidine–2, 4–dione derivatives

The use of flow microreactors in the chemical and pharmaceutical industries offers a number of advantages due to their reduced size compared to batch reactors, the reactors more commonly used by this type of industry. This work aimed at the transposition of the batch process into the continuous flow process in capillary microreactor of the synthesis of (Z)-5-(4-methoxybenzylidene)thiazolidine-2,4-dione (1), (Z)-5-(4-hidroxy-3-methoxybenzylidene)thiazolidine-2,4-dione (2) and (Z)-5-(4-nitrobenzylidene)thiazolidine-2,4-dione (3) which are the base for obtaining drugs through the reaction of the thiazolidine-2,4-dione (TZD) with the aryl aldehydes 4-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde and 4-nitrobenzaldehyde, respectively. The 4-methoxybenzaldehyde showed higher reactivity and TZD showed the highest conversion (100%) in this reaction, followed by the synthesis of (3), which exhibited 72% TZD conversion. The synthesis of (2) showed the lowest conversion of TZD, 62%, possibly due to steric hindrance.