Synthesis and Characterization of (Z)-5-Arylmethylidene-rhodanines with Photosynthesis-Inhibiting Properties

Abstract

A series of rhodanine derivatives was prepared. The synthetic approach, analytical and spectroscopic data of all synthesized compounds are presented. Lipophilicity of all the discussed rhodanine derivatives was analyzed using the RP-HPLC method. The compounds were tested for their ability to inhibit photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts and reduce chlorophyll content in freshwater alga Chlorella vulgaris. Structure-activity relationships between the chemical structure, physical properties and biological activities of the evaluated compounds are discussed. For majority of the tested compounds the lipophilicity of the compound and not electronic properties of the R1 substituent were decisive for PET-inhibiting activity. The most potent PET inhibitor was (5Z)-5-(4-bromobenzylidene)-2-thioxo-1,3-thiazolidin-4-one (IC50 = 3.0 μmol/L) and the highest antialgal activity was exhibited by (5Z)-5-(4-chlorobenzylidene)-2-thioxo-1,3-thiazolidin-4-one (IC50 = 1.3 μmol/L).

A Rapid and Green Procedure for the Synthesis of 5- Arylidene Rhodanine Derivatives

“…Arylmethylidenerhodanines can form two isomers. However, all arylmethylidenerhodanines reported in the present paper were obtained as single (Z)-isomers [3,13]. The reusability of the catalyst was examined in the synthesis of 5-benzylidene rhodanine.…”

“…The preparation of 5-arylidene rhodanine derivatives can be carried out by condensation of aromatic aldehydes and rhodanine in the presence of various catalysts such as glycine [4], ammonium acetate [5][6], 2,2,6,6-tetramethyl piperidine [7][8], NaOAc/HOAc [2,9-10], 1-butyl-3-methyl imidazolium hydroxide [11][12], NH 4 Cl/NH 4 OH [13], ethylenediammonium diacetate [14], K 2 CO 3 /[bmim]BF 4 /H 2 O [15], piperidine [1,[16][17], piperidine/AcOH [18][19][20]. Unfortunately, many of these methods suffer from one or other limitations such as low product yields, tedious work-up procedures, relatively long reaction time, use of organic solvent, use of special apparatus, use of expensive catalyst and difficulty in recovery and reusability of the catalyst.…”

(Z)-3-Amino-5-(pyridin-2-ylmethylidene)-2-thioxo-1,3-thiazolidin-4-one

“…Configuration on the exocyclic double-bond can be determined on the basis of NMR spectra where 1 H-NMR signals of the methine-group hydrogen for (Z)-isomers are more downfield compared to those expected for (E)-isomers. In our previous papers [5,7], the experimental signals of the -CH= group of various rhodanine derivatives were compared with the values reported previously in literature and the values predicted in silico. The (Z)-Isomers of arylmethylidenerhodanines exhibited experimental methine group shifts between 7.39-7.94 ppm, while (E)-isomers had methine group shifts in the range 6.78-7.01 ppm [5].…”

“…Our research group has studied derivatives of rhodanine as potential antifungal and antimycobacterial agents [3][4][5][6]. Their influence on some photosynthetic processes was studied as well [7]. Some derivatives of 3-aminorhodanine were also prepared within these studies.…”

Three-Component, One-Flask Synthesis of Rhodanines (Thiazolidinones)

“…Rhodanines (2-thioxo-1,3-thiazolidin-4-ones) are 5-membered ring sulfur/nitrogen heterocycles some of which have antimalarial, antibacterial, antifungal, antiviral, antitumor, anti-inflammatory or herbicidal activities. 6 5- Arylidene rhodanines are common, 7–14 whereas 5- alkylidene rhodanines are rare. 15–17 In one direct comparison, 5- alkylidene rhodanine A was more potent as a class C β-lactamase inhibitor than the corresponding vinylogous 5- arylidene rhodanine B (Figure 1).…”