NOVELTY - Preparation of a propargylated aminoindan compound involves: a) reacting an indanone derivative or its salt with the propargylamine or its salt in the presence of a Lewis acid; and b) subjecting the resultant reaction mixture to reduction.    USE - For preparation of a propargylated aminoindan compound e.g. rasagiline or its salt such as rasagiline mesylate (claimed) useful as irreversible inhibitor of monoamine oxidase for treating idiopathic Parkinson's disease, depression, Attention Deficit Disorder, Attention Deficit and Hyperactivity Disorder, Tourett's Syndrome, Alzheimer's Disease and other dementias.    ADVANTAGE - The rasagiline or its salt obtained by this process has any individual impurity of less than 0.15 area % and total impurities of not greater than 0.5 area % as measured by chiral high performance liquid chromatography. The rasagiline or its salt obtained by this process has indan-1-yl-di-prop-2-ynyl-amine or its enantiomer and 1-indanol each in an amount not greater than 0.15 area %, as measured by high performance liquid chromatography. The propargylated aminoindans or their salts obtained have purity greater than 98.5% as determined by chiral high performance liquid chromatography. The processes require a few steps, thus making the processes applicable on an industrial scale. The compounds produced by the processes are suitable for use as pharmaceuticals, or as starting materials or as intermediates in the production of a variety of pharmaceuticals. The processes are not only simple without employing environmentally aggressive chemicals, but more significantly, provide the least formation of undesirable bisalkylated by-products, while concomitantly producing final products in high yield and purity. The rasagiline or its salt has purity of at least 98 (preferably at least 99) area %, as determined by chiral HPLC. The processes for the preparation of propargylated aminoindans are simple, eco-friendly, robust, reproducible and easily scalable.    DETAILED DESCRIPTION - Preparation (P1) of a propargylated aminoindan compound of formula (I) involves: a) reacting an indanone derivative or its salt of formula (II) with the propargylamine or its salt of formula H2N-CH2-C?=CH (III) in the presence of a Lewis acid; and b) subjecting the resultant reaction mixture to reduction.    R1=H or -O-C(O)-N(R2)-R3;    R2=1-4C alkyl;and    R3=H or 1-4C alkyl.    INDEPENDENT CLAIMS are included for the following:    (1) rasagiline or its salt obtained having any individual impurity of less than 0.15 area % and total impurities of not greater than 0.5 area % as measured by chiral high performance liquid chromatography;    (2) rasagiline or its salt having indan-1-yl-di-prop-2-ynyl-amine or its enantiomer and 1-indanol each in an amount of not greater than 0.15 area %, as measured by high performance liquid chromatography; and    (3) a pharmaceutical composition comprising rasagiline or its salts obtained by the process (P1) and at least one carrier.