Polysubstituted Fused Ring Bicyclic Thiohydantoins from Aminocarbo-N-thioylpyrrolidines Derived from Azomethine Ylide 1,3-Dipolar Cycloadditions
Nural, Yahya | Dondas, Haci Ali
Highly substituted bicyclic thiohydantoins fused to pyrrolidines were prepared from aminocarbo-N-thioylpyrrolidines derived from alpha-amino acid esters via imine azomethine ylide 1,3-dipolar cycloadditions and subsequent reaction with aroylisothiocyanates. Aminocarbo-N-thioylpyrrolidines efficiently undergo cyclisation in the presence of sodium methoxide to form bicyclic N-substituted thiohydantoins with concomitant cleavage of the N-acyl group in good to excellent yield. And also some interesting both regiospecific and stereospecific rearrangement to the bicyclic fused thiocarbamoil pyrrolidine and bicyclic thiohydantoin were observed.
Determination of Acid Dissociation Constants (pKa) of Bicyclic Thiohydantoin-Pyrrolidine Compounds in 20% Ethanol-Water Hydroorganic Solvent
Nural, Yahya | Dondas, Haci Ali | Belveren, Samet | Gemili, Muge
The acid dissociation constants of potential bioactive fused ring thiohydantoin- pyrrolidine compounds were determined by potentiometric titration in 20% ( v/ v) ethanol- water mixed at 25 +/- 0.1(0) C, at an ionic background of 0.1 mol/ L of NaCl using the HYPERQUAD computer program. Proton affinities of potential donor atoms of the ligands were calculated by AM1 and PM3 semiempiric methods. We found, potentiometrically, three different acid dissociation constants for 1a- f. We suggest that these acid dissociation constants are related to the carboxyl, enol, and amino groups.