Tamsulosin Impurity 1 synthesis

Yield:116091-64-6 71.7%

Reaction Conditions:

Stage #1: (R)-1-phenyl-ethyl-amine;2-methoxy-5-(2-oxopropyl)benzenesulfonamidewith sodium tris(acetoxy)borohydride;acetic acid in dichloromethane at 30 - 35; for 16 h;
Stage #2: with hydrogenchloride in water; for 0.5 h;

Steps:

1.1 Step 1. Synthesis of 5-[[(2R)-2-[(1R)-N-(1-methylbenzyl)]amino]propyl]-2-methoxybensulfonamide hydrochloride

Put methylene chloride (2250mL, 15V) into a 10L three-necked flask,(R)-1-Phenethylamine (150.0g, 1.0eq), turn on the stirring,Add 5-acetone-2-methoxybenzenesulfonamide (316.2g, 1.05eq),Slowly add acetic acid (74.3g, 1.0eq), raise the temperature to 30-35°C,Add sodium triacetoxyborohydride (314.8g, 1.2eq), stir for 16h, stop the reaction.Add 3mol/L dilute hydrochloric acid aqueous solution (958.0g) dropwise, stir for 30min, add dropwise 30% sodium hydroxide aqueous solution (1096.0g), stir to separate layers, add saturated brine (1500.0g) to the organic phase, stir for 15min, pass the diatom Soil (30.0g), separate the organic phase, add 33% hydrogen chloride ethanol solution (225.0g) dropwise, stir for 60 minutes, evaporate a large amount of solvent under reduced pressure, add acetonitrile (2250mL), stir for 30min, filter, and wash the wet product with acetonitrile The filter cake was vacuum dried to obtain 342.0 g of product, with a chemical purity of 99.7%, a chiral purity of 97.2:2.8, and a yield of 71.7%.

References:

CN111320559,2020,A Location in patent:Paragraph 0041-0043