TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No general preparation is given. Preferred Definitions:    R1=aromatic group;and    R2+R3=5 or 6 membered ring.    SPECIFIC COMPOUNDS - 18 Thiazolidine-type compounds (I) e.g. 2-(5-((4-(4-(2,2-diphenylethenyl)phenyl)-1H,2H,3H,3aH,4H,8bH-cyclopenta(b)indol-7-yl)methylidene)-4-oxo-2-((5E)-4-oxo-3-(propan-2-yl)-2-sulfanylidene-1,3-thiazolidin-5-ylidene)-1,3-thiazolidin-3-yl)acetic acid of formula (IA), 2-(5-((4-(4-(2,2-diphenylethenyl)phenyl)-1H,2H,3H,3aH,4H,8bH-cyclopenta(b)indol-7-yl)methylidene)-4-oxo-2-((5E)-4-oxo-3-(pentan-3-yl)-2-sulfanylidene-1,3-thiazolidin-5-ylidene)-1,3-thiazolidin-3-yl)acetic acid, 2-(5-((4-(4-(2,2-diphenylethenyl)phenyl)-1H,2H,3H,3aH,4H,8bH-cyclopenta(b)indol-7-yl)methylidene)-4-oxo-2-((5E)-4-oxo-3-(1-phenylethyl)-2-sulfanylidene-1,3-thiazolidin-5-ylidene)-1,3-thiazolidin-3-yl)acetic acid, 2-(5-((4-(4-(2,2-diphenylethenyl)cyclohexa-2,4-dien-1-yl)-1H,2H,3H,3aH,4H,8bH-cyclopenta(b)indol-7-yl)methylidene)-2-((5E)-3-(ethyl(methyl)amino)-4-oxo-2-sulfanylidene-1,3-thiazolidin-5-ylidene)-4-oxo-1,3-thiazolidin-3-yl)acetic acid, and 2-(5-((4-(4-(2,2-diphenylethenyl)phenyl)-1H,2H,3H,3aH,4H,8bH-cyclopenta(b)indol-7-yl)methylidene)-4-oxo-2-((5E)-4-oxo-3-(pyrrolidin-1-yl)-2-sulfanylidene-1,3-thiazolidin-5-ylidene)-1,3-thiazolidin-3-yl)acetic acid are disclosed.    EXAMPLE - 4-(4-(2,2-Diphenylethenyl)phenyl)-1H,2H,3H,3aH,4H,8bH-cyclopenta(b)indole-7-carbaldehyde (1.1), (3'-(dimethylamino)-4,4'-dioxo-2'-thioxo-2,5'-bi-1,3-thiazolidin-3-yl)acetic acid (1.4), ammonium acetate (0.05), and acetic acid (100 ml) were mixed, and heated at 120 degrees C for 8 hours. The obtained mixture was cooled, precipitated, filtered, and dried to obtain crude product (1.2 g). The obtained crude product was purified by silica gel column chromatography to obtain 2-(5-((4-(4-(2,2-diphenylethenyl)phenyl)-1H,2H,3H,3aH,4H,8bH-cyclopenta(b)indol-7-yl)methylidene)-4-oxo-2-((5E)-4-oxo-3-(propan-2-yl)-2-sulfanylidene-1,3-thiazolidin-5-ylidene)-1,3-thiazolidin-3-yl)acetic acid.