'Synthesis, Characterization and Immunosuppresant Activity of Isatins'

Novel nine title derivatives of isatin were synthesized as outlined in scheme I by following steps: ¿ Synthesis of Schiff¿s bases using isatin and various amino acids. ¿ Synthesis of acyl chlorides ¿ Synthesis of carboxylic acids possessing amide linkage. The scheme involves the following steps: ¿ Synthesis of Schiff¿s bases was carried out by refluxing isatin and various amino acids in the presence of glacial acetic acid using ethanol as solvent. ¿ The acyl chlorides were synthesized by subjecting the Schiff¿s bases to 2 h of reflux in the presence of excess of thionyl chloride. The solid product was obtained by distilling out the excess thionyl chloride. ¿ The amides were synthesized by stirring amino acids and acyl chloride in 2 N sodium hydroxide over a period of 2 h at room temperature. The solution was further neutralized using dilute hydrochloric acid to obtain the compound. The completion of reaction was ascertained by TLC. The structures of title compounds were characterised by IR and NMR. The purpose of the synthesis was to evaluate the newly synthesised compounds for their immunosuppressive activity by carrying out peripheral lymphocyte reduction activity on Wistar rats.