<strong>Study of the effect of solvent and different Lewis acids in one pot multicomponent microwave assisted reaction for the chemoselective generation of </strong><strong>1.4-thiazepan-3-ones and 4-tiazolidinones.</strong>

Abstract

Abstract:With the aim of exploring the best reaction conditions for the diastereoselective synthesis of the 1,4-thiazepan-3-ones (4) and 4-thiazolidinones (5), we have studied the effect on solvent variation and the aggregation of AlCl3 and different zeolites as Lewis acid catalysts to the three-component microwave assisted reaction between 2,3:4,5-di-O-isopropylidene--Darabino-hexos-2-ulo-2,6-pyranose (1), benzotiazole (3) and thioglycolic acid (2). Based on the results of previous studies of our group, we discuss here two microwave assisted methods: multicomponent reaction in the presence of the catalysts (Method A) and sequential reaction with generation of the corresponding intermediates and subsequent addition of the catalysts coordinated to thioglycolic acid (Method B).

Microwave Assisted Three Component Reaction Conditions to Obtain New Thiazolidinones with Different Heterocyclic Skeletons

“…We have previously study the optimal microwave conditions for the synthetic strategy for the preparation of 4-thiazolidinones (5) starting from 2,3:4,5-di-O-isopropylidene-β-D-arabino-hexos-2ulo-2,6-pyranose (1a), mercaptoacetic acid (2) and different aromatic and heteroaromatic amines (3), under 300 W and 120 °C without solvent (Figure 1) [10]. Depending on the substrate structure, two different type of products could be possible: benzothiazepines (4) and 4-thiazolidinones (5).…”