Patent ID: 8455640

Claim:
A method for the preparation of a compound of Formula-1, wherein R is M is Ca +2 , the method comprising: a) reacting a compound represented by the following structural formula wherein R is defined as above and R 2 is wherein: R 5 is H, alkyl, alkoxy, haloalkyl, monohaloalkyloxy, or dihaloalkyloxy; and X is N-alkyl; with a compound of Formula-4 in the presence of an alkali or alkaline earth metal base in a polar aprotic solvent to give a condensed product, which is reacted in-situ with trifluoroacetic acid in a second solvent then hydrolyzed under basic conditions in aqueous acetonitrile then reacted with an organic amine base in a third solvent to give a compound which is purified in a fourth solvent and, optionally, dried to give a compound of Formula-5, wherein R is defined as above and organic amine is selected from methyl amine, ethyl amine, tertiarybutyl amine, diisopropyl amine, dicyclohexyl amine, isobutyl amine, n-butylamine, (+/−) 2-butyl amine, phenyl ethyl amine, morpholine and pyrrolidine; b) treating the compound Formula-5 with an alkali base to obtain a reaction mixture containing a compound of Formula-6: wherein R is defined as above and M is Na + , K + or Li + , and adjusting the pH of the reaction mixture to 8.0 to 9.2 by washing the reaction mixture with tertiary butyl acetate or by directly distilling the reaction mixture; c) optionally, isolating from the reaction mixture the compound of Formula-6; and d) adding the aqueous phase of the reaction mixture from step (b) or an aqueous solution of the isolated compound of Formula-6 from step (c) to a solution of calcium chloride or calcium acetate in a solvent to give the compound of Formula-1.