Abstract
Based on the previously obtained structural information, (rac)3-substituted 4-carboxy-1, 3-thiazolidine-2-thiones 10 were designed as new aldose reductase inhibitors which might be helpful in treating the chronic complications of diabetes. After several trials to find efficient reaction conditions for preparation of the precursors 15 of compounds 10, a catalytic thermal rearrangement reaction of 14 proved to be practically availavle. Thus, various 3-substituted 4-methoxycarbonyl-1, 3-thiazolidine-2-thiones 15a and 15d-t were readily synthesized by heating the corresponding 2-subsituted thio-Δ2-1, 3-thiazolines 14a and 14d-t at 120°C in the presence of 0.1 mol eq of the corresponding halides 13a and 13d-t without any organic solvent (Sykes conditions). A plausible reaction pathway for the catalytic thermal rearrangement reaction of 14a or 14d-t is presented.
