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<DIV><FONT face=Arial size=2>Dear all,</FONT></DIV>
<DIV><FONT face=Arial size=2>I have asked about creating an urea here before and
recieved some help in the matter and decided to try my luck once again. I have
two questions:</FONT></DIV>
<DIV><FONT face=Arial size=2>1) I have an aniline which i react with triphosgene
to form an isocyanate. this isocyanate is then reacted with another aniline
(picomolar amounts of a radioactive aniline) to form an urea bond. I cannot seem
to get a good isocyanate. sometimes when i add the second aniline i get
a complete reaction in 30 mins at room temp. and sometimes no reaction at
all.</FONT></DIV>
<DIV><FONT face=Arial size=2>Is there a way to isolate the isocyanate? Is there
a way such as IR to make sure it is pure isocyanate? Can i do column
chromatography in a glove box?</FONT></DIV>
<DIV><FONT face=Arial size=2>we can buy high-purity isocyanates so there must be
a way to do this....</FONT></DIV>
<DIV><FONT face=Arial size=2>2) can anyone give me any further ideas about
precursors for urea bond formation?</FONT></DIV>
<DIV><FONT face=Arial size=2>I have tried isopropenyl as a leaving group without
much success and I know CDI is used (but mostly aliphatic amines)</FONT></DIV>
<DIV><FONT face=Arial size=2>any ideas and referance aritcles will be most
welcome</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Ohad Ilovich</FONT></DIV></BODY></HTML>
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