(R)-Rasagiline base pure (30 g) was dissolved in HBr (250 ml) and the solution was heated to reflux for 36 h. After the completion of reaction the mixture was cooled, diluted with water (500 ml) and slowly the solution was basified using aqueous ammonia solution. The mixture was extracted with methyl tertiary butyl ether (MTBE). The separated MTBE layer was evaporated to get a dark brown oil which exhibited 3 spots on TLC, two of which were of the desired compounds i.e., N-2-Propene-1-yl-2-bromo-(R)-aminoindan hydrobromide (Impurity A) and N-2-Propene-1-yl-3-bromo-(R)-aminoindan hydrobromide (Impurity B). The third spot had same Rf as that of the starting material i.e., the unreacted Rasagiline base. The products formed were separated by column chromatography (silica gel) using hexane-ethyl acetate mixture (75:25) as mobile phase to give pure N-2-Propene-1-yl-2-bromo-(R)-aminoindan (15% overall yield) and N-2-Propene-1-yl-3-bromo-(R)-aminoindan (15% overall yield).
