Patent ID: 7964737

Claim:
A process for producing purified 2-(n-butyl)-3[[2′-(tetrazol-5-yl)biphenyl-4-yl]methyl]-1,3-diazaspiro[4.4]non-1-en-4-one, comprising: (a) condensing 2-(n-butyl)-1,3-diazaspiro[4,4]non-1-ene-4-one or an acid addition salt thereof with 4-(bromomethyl)-2′-cyanobiphenyl of in the presence of a base, wherein the base comprises at least one alkoxide, hydride, hydroxide or carbonate of an alkali metal, and a mixture of solvents comprising at least one polar aprotic solvent and at least one non-polar solvent, wherein the solvents in the mixture of solvents are selected from the groups consisting of polar aprotic and non-polar solvents, to produce 2-(n-butyl)-3[[2′-(cyano)biphenyl-4-yl]methyl]-1,3-diazaspiro[4.4]non-1-en-4-one, which is purified in presence of mixture of water and an alcoholic solvent; (b) treating the purified 2-(n-butyl)-3[[2′-(cyano)biphenyl-4-yl]methyl]-1,3-diazaspiro[4.4]non-1-en-4-one with azide in the presence of an triethyl amine and acetic acid employing a solvent medium, wherein the solvent medium comprises at least one solvent selected from the group consisting of aliphatic hydrocarbons, ketones, esters, ethers, alcohols, toluene and xylene, to produce 2-(n-butyl)-3-[[2′-(tetrazol-5-yl)biphenyl-4-yl]methyl]-1,3-diazaspiro[4.4]non-1-en-4-one; and (c) isolating the 2-(n-butyl)-3-[[2′-(tetrazol-5-yl)biphenyl-4-yl]methyl]-1,3-diazaspiro[4,4]non-1-en-4-one employing an organic solvent, to obtain the purified 2-(n-butyl)-3-[[2′-(tetrazol-5-yl)biphenyl-4-yl]methyl]-1,3-diazaspiro[4.4]non-1-en-4-one.