A PROCESS FOR PREPARATION OF MIRABEGRON AND ALPHA CRYSTALLINE FORM THEREOF

摘要

An improved process for the preparation of Mirabegron of formula (I) where 4-nitrophenylethylamine of formula (III) or its acid addition salt of formula (IIIa) reacted with compound of formula (XII) in a solvent, optionally in presence of base and/or catalyst to obtain (R)-2-hydroxy-N-[2-(4-nitrophenyl)ethyl]-2-phenylacetamide of formula (XIII) followed by reducing (R)-2-hydroxy~N-[2-(4-nitrophenyl)ethyl]-2-phenylacetamide of formula (XIII) in a solvent to obtain (R)-2-[2'-(4-nitrophenyl)ethyl]amino]-l-phenylethanol of formula (XIV), optionally converting it into its acid addition salt of formula (XlVa); reducing (^^-P'^-nitrophenyOethyijamino]-l-phenylethanol of formula (XIV) or its acid addition salt of formula (XIVa) further in solvent to obtain (#)-2-[[2-(4-aminophenyl)ethyl]-amino]-l-phenylethanol of formula (XV) or its acid addition salt of formula (XVa) respectively; and reacting compound (R)-2-[[2-(4-aminophenyl)ethyl]-amino]~I-phenylethanol of formula (XV) or its acid addition salt of compound of formula (XVa) with compound of formula (VII) in solvent, optionally in the presence of acid, and/or a catalyst to obtain Mirabegron of formula (I) which is further isolated as its a- crystalline form. The compound of formula (XIV) used in the foregoing process can also be prepared by reacting with a compound of formula (III) or acid addition salt of compound of formula (IIIa) in presence of a solvent, a catalyst and optionally in presence of a base to obtain compound of formula (XIV) optionally converting it into its acid addition salt of formula (XlVa); and the same is used in the above-referred process. The compound of formula (XV) used in the foregoing process can also be prepared by reacting a compound of formula (III) or its acid addition salt of formula (Ilia) with a compound of formula (XVI) in a solvent, optionally in presence of a base, optionally in presence of a catalyst to obtain compound of formula (XVII); and optionally isolate the compound of formula (XVII) followed by reducing the compound of formula (XVII) using reducing agent, in a solvent, optionally in presence of a base, optionally in presence of a catalyst to obtain compound of formula (XV) which is further used in the above-referred process for the preparation of Mirabegron of formula (I) and its a-crystalline form. Another additional single-pot process for preparation of Mirabegron of formula (I) is disclosed, wherein compound of formula (XV) or its acid addition salt of formula (XVa) reacted with compound of formula (XVIII) in presence of a solvent and oxidizing agent, optionally in presence of base, optionally in presence of a catalyst to obtain Mirabegron of formula (I).