2-Methoxy-5-(2-oxopropyl)benzenesulfonamide

A method of preparation of tamsulosin (II) according to the prior art in comparison with the method with included steps according to the invention 1. The method according to the prior art; 1. 1. Chlorosulfonation in two steps according to US 4, 731, 478 (1988); 1.2. VII yield 40percent yield 74percent III total yield 30percentChlorosulfonic acid (426 g, 3.656 mol) was cooled to -10 ~ (-15) ° C. 4-methoxyphenylacetone (100 g, 0.609 mol) was added at a rate such that the temperature of the reaction mixture did not exceed 5 ° C.After addition of the whole amount of methoxyphenylacetone, the reaction mixture was allowed to warm to room temperature.The mixture was stirred at room temperature for 2 hours. The reaction mixture was then poured into a stirred mixture of ice (1500 g) and water (1600 ml).The formed crystals were filtered off and washed with cold water (200 ml).The crystals were dissolved in ethyl acetate (300 ml). Ammonia water (600 ml) was cooled to -5 ° C, and the above ethyl acetate solution was gradually added at a constant rate so that the temperature did not exceed 5 ° C.The mixture was then allowed to warm to room temperature and stirred overnight. The resulting crystals were filtered off and washed with water (200 ml) and ethanol (100 ml).The crystals of the crude product were recrystallized from ethanol to give 63 g of the title compound.comparative; A method of preparation of tamsulosin (II) according to the prior art in comparison with the method with included steps according to the invention 1. The method according to the prior art; 1. 1. Chlorosulfonation in two steps according to US 4, 731, 478 (1988); 1.2. VII yield 40percent yield 74percent III total yield 30percentChlorosulfonic acid (426 g, 3.656 mol) was cooled to -10 ~ (-15) ° C. 4-methoxyphenylacetone (100 g, 0.609 mol) was added at a rate such that the temperature of the reaction mixture did not exceed 5 ° C.After addition of the whole amount of methoxyphenylacetone, the reaction mixture was allowed to warm to room temperature.The mixture was stirred at room temperature for 2 hours. The reaction mixture was then poured into a stirred mixture of ice (1500 g) and water (1600 ml).The formed crystals were filtered off and washed with cold water (200 ml).The crystals were dissolved in ethyl acetate (300 ml). Ammonia water (600 ml) was cooled to -5 ° C, and the above ethyl acetate solution was gradually added at a constant rate so that the temperature did not exceed 5 ° C.The mixture was then allowed to warm to room temperature and stirred overnight. The resulting crystals were filtered off and washed with water (200 ml) and ethanol (100 ml).The crystals of the crude product were recrystallized from ethanol to give 63 g of the title compound.

Tamsulosine intermediate

Molecular Weight:243.28
XLogP3:0.1
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:4
Exact Mass:243.05652907
Monoisotopic Mass:243.05652907
Topological Polar Surface Area:94.8
Heavy Atom Count:16
Complexity:346
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes