solvent used for extraction can be selected from any suitable organic solvent in the process of present invention the ph of organic layer is adjusted by using orthophosphoric acid the reported processes generally use sulphuric acid for ph adjustment acid base purification this results into sulphate salt of compound of formula vi the sulphate salt is difficult to remove as it does not separate in aqueous layer rather forms an oily layer which is difficult to isolate and also entraps many impurities when orthophosphoric acid is used the resultant salt does not isolate as oil rather goes in aqueous layer and can be isolated easily by further processing and is obtained with high purity the fifth step of the process is to convert u00b1 3 2 benzyloxy 5 bromophenyl 3 phenylpropyl diisopropylamine to u00b1 4 benzyloxy 3 3 diisopropylamino 1 phenylpropyl benzoic acid hydrochloride by the process of u s pat no 6 713 464b1 in step vi u00b1 4 benzyloxy 3 3 diisopropylamino 1 phenylpropyl benzoic acid is converted by reduction to give u00b1 4 benzyloxy 3 3 diisopropylamino 1 phenylpropyl phenyl methanol the reduction is performed by using borane containing reducing agents such bh 3 dms boron dimethyl sulphide complex bh 3 thf boron thf the process of present invention provides direct reduction of acidic group.