Method for producing α-fluoromalonic acid dialkyl esters
View Patent ↗The invention relates to a new, advantageous method for the preparation of dialkyl α-fluoromalonates.
1. A method for the preparation of compounds of the structure (I),
wherein
R 1 is alkoxy with 1 to 4 carbon atoms and
R 2 is hydrogen or fluorine,
comprising reacting a compound of structure (II),
wherein
R 1 has the meaning described above and
R 3 is hydrogen, fluorine or chlorine,
with 1.4 to 2.0 mol equivalents of an addition product of hydrogen fluoride and triethylamine per mol of starting material of structure (II) at temperatures of 103° C. to 115° C. at 800 to 1200 mbar.
2. The method as described in claim 1 , wherein R 1 is methoxy or ethoxy.
3. The method as described in claim 1 , wherein R 2 and R 3 are hydrogen.
4. The method as described in claim 1 , wherein the temperature is from 105° C. to 110° C.
5. The method as described in claim 1 , wherein the addition product of hydrogen fluoride and triethylamine contains 1.2 to 1.8 mols hydrogen fluoride per mol triethylamine.
6. The method as described in claim 2 , wherein R 2 and R 3 are hydrogen.
7. The method as described in claim 2 , wherein the temperature is from 105° C. to 110° C.
8. The method as described in claim 2 , wherein the addition product of hydrogen fluoride and triethylamine contains 1.2 to 1.8 mols hydrogen fluoride per mol triethylamine.