Rhodanine, Isorhodanine, and Thiorhodanine

Rhodanine, Isorhodanine, and Thiorhodanine.—Phosphorus pentasulphide converts 5,5-diphenylthiazolidine-2,4-dione (260) successively into the monothione (261) and 2,4-dithione (262), in refluxing dioxan and tetralin (b.p. 180 °C), respectively. Treatment of the 2,4-dithione (262) with aluminium chloride in boiling toluene causes simultaneous desulphurization and rearrangement, with formation of 4,5-diphenyl-A -thiazoline-2-thione (263). The reaction resembles that previously established in respect of the comparable 5,5-diphenyldithiohydantoin. 

5-Benzylidenethiorhodanines are accessible from the corresponding rhodanines by the action of phosphorus pentasulphide in anhydrous dioxan.  

The action of alkyl halides on rhodanine and its 5-benzylidene derivatives 

Jimenez, R. Vergona, and M. R. Cohen, Intemat. J. Peptide Protein Res., 

Lempert and J. Nyitrai, Tetrahedron Letters, 1965, 2927 Acta Chim. Acad. Sci. Hung., 

---

The i.r. spectra of rhodanine, isorhodanine, and thiorhodanine, together with those of several derivatives, have been studied in detail. - ... 

Rhodanines.—The 2,4-oxothiones and 2,4-dithiones of thiazolidine, generally known by their trivial names rhodanine (361), isorhodanine (362), and thiorhodanine (363), have been the subject of continued studies, particularly by Russian research workers, with the ultimate aim of their incorporation into cyanine and other dye structures. They resemble one another in their general properties and are here dealt with together. 

---