Process for producing phosphinates
The present invention relates primarily to a process for producing particular phosphinates (phosphonous acid monoesters) and use thereof for producing biologically active substances which may be used in the pharmaceutical or agrochemical sector, preferably for producing phosphorus-containing amino acids.
1. A process for producing a compound of formula (I)
comprising reacting a compound of formula (II)
with a compound of formula (III)
R 2 —OH (III)
wherein in each case:
R 1 represents (C 1 -C 12 )-alkyl, (C 1 -C 12 )-haloalkyl, (C 6 -C 10 )-aryl, (C 6 -C 10 )-haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 4 -C 10 )-cycloalkyl or (C 4 -C 10 )-halocycloalkyl,
R 2 represents (C 3 -C 12 )-alkyl, (C 3 -C 12 )-haloalkyl, (C 6 -C 10 )-aryl, (C 6 -C 10 )-haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 4 -C 10 )-cycloalkyl or (C 4 -C 10 )-halocycloalkyl,
R 3 and R 4 each independently of one another represent methyl or ethyl,
in the presence of an acidic catalyst and in the presence of water.
2. The process according to claim 1 , wherein the total amount of water used is at least 0.8 molar equivalents, based on the total amount of compounds of formula (II) used.
3. The process according to claim 1 , wherein the total amount of water used is 1 to 5 molar equivalents, based on the total amount of compounds of formula(II) used.
4. The process according to claim 1 , wherein the total amount of water used is 1 to 3 molar equivalents, based on the total amount of compounds of formula (II) used.
5. The process according to claim 1 , wherein the total amount of water used is 1 to 2 molar equivalents, based on the total amount of compounds of formula (II) used.
6. The process according to claim 1 , wherein the total amount of compounds of formula (III) used is 1 to 25 molar equivalents, based on the total amount of compounds of formula (II) used.
7. The process according to claim 1 , wherein the total amount of compounds of formula (III) used is 3 to 15 molar equivalents, based in each case on the total amount of compounds of formula (II) used.
8. The process according to claim 1 , wherein the pKa of the acidic catalyst under standard conditions is less than 3.
9. The process according to claim 1 , wherein the acidic catalyst is selected from the group consisting of H 3 PO 3 , H 2 SO 4 , HCl, HBr, HClO 4 , dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, methanesulphonic acid, trifluoromethanesulphonic acid, benzenesulphonic acid, p-toluenesulphonic acid, acidic ion exchangers, acidic polysiloxanes and acidic zeolites.
10. The process according to claim 1 , wherein the reaction is carried out as a one-pot reaction.
11. The process according to claim 1 , wherein the reaction is carried out at a temperature in a range from 30 to 140° C.
12. The process according to claim 1 , wherein the reaction is carried out in an inert diluent or diluent-free.
13. The process according to claim 1 , wherein
R 1 represents (C 1 -C 6 -alkyl, (C 1 -C 6 )-haloalkyl, (C 6 -C 8 -aryl, (C 6 -C 8 -haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 5 -C 8 -cycloalkyl or (C 5 -C 8 -halocycloalkyl,
and
R 2 represents (C 3 -C 8 )-alkyl, (C 3 -C 8 )-haloalkyl, (C 6 -C 8 -aryl, (C 6 -C 8 -haloaryl, (C 7 -C 10 )-aralkyl, (C 7 -C 10 )-haloaralkyl, (C 5 -C 8 -cycloalkyl or (C 5 -C 8 -halocycloalkyl.
14. The process according to claim 1 , wherein
R 1 represents (C 1 -C 4 )-alkyl, (C 1 -C 4 )-haloalkyl or (C 6 -C 8 -aryl
R 2 represents (C 3 -C 6 -alkyl or (C 3 -C 6 )-haloalkyl.
15. The process according to claim 1 , wherein
R 1 represents methyl or ethyl,
R 2 represents C 4 -alkyl or C 5 -alkyl.
16. The process according to claim 1 , wherein the total amount of water used is at least 0.95 molar equivalents, based on the total amount of compounds of formula (II) used.
17. The process according to claim 1 , wherein the total amount of compounds of formula (III) used is 5 to 10 molar equivalents, based on the total amount of compounds of formula (II) used.
18. The process according to claim 1 , wherein the pKa of the acidic catalyst under standard conditions is less than 2.
19. The process according to claim 1 , wherein the reaction is carried out at a temperature in a range from 50 to 120° C.