[zhuguang21]

dear chemist:
who does thi subject of fosfomycin trometamol?
I have do it now.so,i descover some problems,who can help me.
I preparation fosfomycin trometamol from fosfomycin Phenethylamine salts ,TsOH and trometamol.
fist,I preparation a intermediate with TsOH and trometamol in anhydrous ethanol,i give it a name of "trometamol TsOH salts".this step doesn't problem.
and i prearation fosfomycin trometamol process as follows:
fist step,a mixture of trometamol TsOH salts and anhydrous ethanol, heat to 50deg by water bath.stirred,and add the fosfomycin phenethylamine salt. about 2-5 minute,the solvent will be clear, and Crystal seed was added, stirring on 50 deg for 10 minute,then cool.filtered. obtained crude product.
second step,crude product solvented with warm methanol,filtered,add anhydrous ethanol to obtained product.
so ,problem is:
1.in fist step,the yied about 60-65%,too low.so ,i tryed added the trometamol salt weight,the yied will be add,but the product pH will heighten.i tryed try the stir,solvent weight,as a result was poor. what i can try another some thing of?
2. product  stability  isn't well.about passed two months.impurity will  isn't accept .i tryed some method to change crystal.the same result. who can give me some best advice.thanks! and ,you want to know  other more info for this subject,you can send a MSN messege or an Email to me ,my MSN and E-mail add:zhuguang21@hotmail.com.
this is my fist one subject.thanks!

[zhuguang21]

nobody knowed how do it? maybe i does't describe clarity the subject? but i very worry to konw.