The above problem occurs, among others, in the case of the alkylation of quinine, which degrades at elevated temperatures with the formation of numerous derivatives with similar chemical structures . In our past research, we proposed a favorable method for highly efficient (95% yield) conversion of technical quinine hydrochloride extracted from natural raw material (cinchona bark) into quinine free base , followed by efficient alkylation of quinine using 1-bromoalkanes and DMSO as solvent at 35 °C to reduce the amount of degradation products of the alkaloid . A thorough three-step purification of the crude product yielded QASs with 1-alkylquinium cation in satisfactory yields (>80%) (Scheme 1).