Patent ID: 7282606

Claim:
A process for the preparation of tamsulosin having the following formula 1; the process comprising the steps of: reacting the hydrochloride of sulfonamide 2 with the ether compound 21 to obtain the tamsulosin 1; wherein R 1 is ethyl and R 2 is methyl for tamsulosin 1, R in formula 2 represents Me, as shown by 2A, and the hydrochloride of 2A is shown by 2B; in ether compound 21, R′ represents Et and R″ represents Ts, as shown by the (ether)benzoxy tosylate 21A; where forming sulfonamide hydrochloride salt 2B is done by converting acetamide 5A to (sulfo)acetamide 6A by reacting said acetamide 5A with: (a) chlorosulfonic acid: followed by (b) ammonia in tetrahydrafuran (THF); followed by obtaining said sulfonamide hydrochloride salt 2B under an aqueous hydrochloride solution;