reflux condenser and additional funnel then the mixture was pre heated around 100 110 u00b0 c 1745 u03bcl 20 mmol of trichlorophosphine was added to the hot mixture drop by drop for 15 min to 1 hour then a thick precipitate was formed after heating the mixture for overnight followed by cooling down it the bulk of the chlorobenzene was decanted and the remaining solvent was evaporated under reduced pressure condition the white or yellow residue was taken up in 10 ml of water and heated to reflux for 1 hour 1 3159 g of sodium hydroxide was added to the mixture at room temperature the ph was adjusted around 5 and an orange turbid material was obtained then further 1 6952 g of sodium hydroxide into the mixture the orange turbid material turned to brown when ph became 10 the mixture was filtered with 0 45 u03bcm nylon membrane and then the filtrate was dialyzed with a membrane wherein the molecular weight cut off mwco of the membrane was less than 500 daltons the product was lyophilized and isolated with sephadex g 75 to get 1149 mg of 1 4 7 10 tetraazacyclododecane 1 4 7 10 tetrakis 2 hydroxy propylenebisphosphonate test 1 general radiolabeling procedure of chelator based bone seeking agents with 99m tc 5 mg of the compound of present disclosure ex ob 121 was dissolved in 0 2 ml of water then added tin chloride 0 1 mg in 0 1 ml of water in at room.