Process for preparation of tamsulosin and its aralkylamine derivatives

The present invention discloses a new process for the synthesis of tamsulosin and its aralkylamine derivatives, especially (R)-(-)-5-{2-[2-(2-alkoxyphenoxy) ethylamino] propyl}-2-alkoxybenzenesulfonamides having the following formula 1 (where R1 and R2 represent C1-C4 alkyl groups) and their hydrochloride thereof, and other various pharmaceutical used salts. Tamsulosin hydrochloride (R1=Et, R2=Me, in its hydrochloride salt form) is an antagonist of alpha-A adrenoceptors in the prostate. Tamsulosin HCl occurs as white crystals, which melt with decomposition at approximately 230 DEG C. It is sparingly soluble in water and in methanol, slightly soluble in glacial acetic acid and in ethanol, and practically insoluble in ether.