From: Luis Fernando Garcia Alles (luis.garciaalles$##$ibc.unibe.ch)
Date: Wed May 24 2000 - 03:28:25 EDT
Dear People,
Here I am again with some questions. The problem I have is the following.
I would like to syntesize some analogues of a phosphoester [R-O-PO3(2-)]. I
have thought of replacing one of the OH groups in the phosphate for a
fluorine, to get the phosphofluoridate analogue: R-O-P(F)O2(-). I do not
have too much experience with phosphofluoridates (I only know that they are
very toxic) and consequently I have too many doubts. In the literature
there seems to be very few examples of this kind of compounds, all of them
mainly in the field of nucleotide chemistry. Let me show you some of the
ideas I had to get to this compound:
1) an arbusov reaction between an alpha-bromoketone and the
fluorophosphite F-P(OR')2, to get the protected fluorophosphate
(R-O-P=O(F)OR'). Here I have several doubts:
How to get to the fluorophosphite??, Do you think that I can use ClP(OR')2
or R2N-P(OR')2 to synthesize the F-P(OR')2??
Is the fluoro-phosphite so reactive as the usual phosphites employed in
this kind of reaction??.
Is it the fluorophosphate stable enough as to allow deprotection
(R-O-P=O(F)OR' --> R-O-P=O(F)OH ) in the last step, for instance with Pd
black in HCOOH/MeOH if R' is a benzyl group??
2) Using the reaction between the alcohol ROH and the Chlorophosphate
ClP=O(F)OR'. More doubts:
Do you think that I can easily replace and purify the ChloroFluorophosphate
in a reaction like Cl2P=O(OR') --> ClP=O(F)OR'?? Or even starting from
O=PCl3 introduce first a fluorine and then benzyl alcohol??
Well I have much more doubts, but I do not want to bore you with more
things. I think that the main problem I have is a lack of experience in
phosphate chemistry, and that is why I am wondering about everything before
doing anything.
Well, I hope somebody out there can send me some light, regarding
stability of this kind of compounds, and this kind of things...
In any case, thank you very much to everybody just for reading the
message, and have a very good time.
=====================================
Luis Fernando García Alles, Ph.D.
Departement für Chemie und Biochemie
Universität Bern
Freiestrasse 3
CH-3012 Bern, Schweiz
Tel. ++41 (0)31/631 37 92
Fax ++41 (0)31/631 33 83
E-mail :garcia$##$ibc.unibe.ch
=====================================
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