Polyethylene glycol as an efficient and reusable solvent medium for the synthesis of thiohydantoins using K₂CO₃as catalyst

Potassium carbonate as a green catalyst for Markovnikov addition of azoles to vinyl acetate in PEG

“…Over the past few years, potassium carbonate (K 2 CO 3 ) has been widely used as mild base catalyst in many organic reactions such as monomethylation reactions (18), O-alkylation (19), synthesis of 2H-chromenes (20), thiolysis of epoxides (21), Knoevenagel and Nitroaldol Condensation (22). Using potassium carbonate as green catalyst, our group has successfully carried out the synthesis of substituted 2-amino-4H-chromenes (23), thieno-pyrimidines (24), organomercurials (25), fused pyrimido derivatives (26), and thiohydantoins (27). The various articles reported reactions of K 2 CO 3 not only showing its essentiality for a particular reaction but also depicting its other characteristics like solubility in water, mild character (19,28), easy availability, eco-friendly (29,30), and nontoxic nature (18,23).…”

Regiospecific Formal [3+2] Annulations of α‐keto Sulfines and N‐Substituted Thioureas

“…Several substituted 2‐thioxoimidazolidin‐2‐one derivatives could be generated from benzil derivatives and phenylureas through reaction mode 2 (Scheme 1a) [9] . Similarly, imidazolidine‐2‐thiones could also be obtained from thiourea derivatives and aromatic aldehydes [10] or chloroacetylchloride in this way [11] …”

“…[9] Similarly, imidazolidine-2thiones could also be obtained from thiourea derivatives and aromatic aldehydes [10] or chloroacetylchloride in this way. [11] Heterocumulenes are a highly varied class of compounds, [12] including such species as allenes, ketenimines, ketenes, sulfines, etc. For these heterocumulenes, they can be captured by thioureas to prepare a series of nitrogen-and sulfur-containing heterocycle compounds.…”

Chemistry and Applications of Functionalized 2,4‐Thiazolidinediones

“…This exclusion is based on the study of the reaction of N-(substitutedphenyl)thiourea 69 ai with chloroacetic acid to form 2-substituted iminothiazolidine-4-one, which after oxidation gives thiazolidinedione, not thiohydantoins as had been expected (entry 14, route a). [83] The reaction is processed in basic conditions using K 2 CO 3 in the polyethylene glycol (PEG-400) medium to produce 2,4-thiazolidinedione (entry 15, route b). In addition, further investigations by X-ray diffraction declared that the reaction product is 2,4thiazolidinedione itself, not its iminothiazolidin-4-one analogues, as had wrongly reported.…”