Process for preparing 2,4-dioxotetrahydrofuran-3-carboxylates
View Patent ↗Process for preparing 2,4-dioxotetrahydrofuran-3-carboxylates of the formula (I) and/or (I′) comprising the reaction of a haloacetyl chloride compound of the formula (II) with a malonic ester of the formula (III) in which Hal, R 1 and R 2 have the definitions stated in the application, in the presence of a suitable base and optionally in the presence of a solvent; the addition of a sufficient amount of water to the reaction mixture; and the isolation of the desired 2,4-dioxotetrahydrofuran-3-carboxylate.
1. A process of preparing 2,4-dioxotetrahydrofuran-3-carboxylates of formula (I):
wherein R 1 is C 1-12 alkyl, C 1-12 haloalkyl, C 5-18 aryl, C 5-18 haloaryl, C 7-19 alkylaryl or C 7-19 arylalkyl, or is alkoxyalkyl of the formula -[A-O] m -B, in which A is C 2-4 alkanediyl (alkylene), B is C 1-6 alkyl and m is 1 or 2, which process comprises:
(a) reacting a compound of formula (III)
wherein R 2 is selected from the group consisting of C 1-12 alkyl, C 1-12 haloalkyl, C 5-18 aryl, C 5-18 haloaryl, C 7-19 alkylaryl or C 7-19 arylalkyl, or are alkoxyalkyl of the formula -[A-O] m -B, in which A is C 2-4 alkanediyl (alkylene), B is C 1-6 alkyl and m is 1 or 2, with a base to give a deprotonated compound,
wherein the base is sodium methoxide
(b) reacting the deprotonated compound with a compound of formula (II)
wherein Hal is selected from the group consisting of chlorine, bromine and iodine; and
(c) adding water; wherein the process is effected in one pot.
2. The process according to claim 1 , wherein R 1 and R 2 each independently of one another are methyl, ethyl, isopropyl, propyl and benzyl.
3. The process according to claim 1 , wherein the ratio of malonic ester of the formula (III) to the base used is in the range from about 1:0.8 to about 1:1.5.
4. The process according to claim 1 , wherein the ratio between haloacetyl chloride and water is in the range from about 1:0.5 to about 1:100.
5. The process according to claim 1 , wherein the base is reacted with the compound (III) at an internal temperature in the range from about 50° C. to about 250° C.
6. The process according to claim 1 wherein the compound (II) is reacted at an internal temperature in the range from about 0° C. to about 50° C.
7. The process according to claim 1 further comprising at least one solvent.
8. The process according to claim 7 wherein the at least one solvent has a boiling range of from 40° C. to 250° C.
9. The process according to claim 7 wherein the solvent is xylene.
10. The process according to claim 1 wherein R 1 is methyl.
11. The process according to claim 1 wherein R 2 is methyl.
12. The process according to claim 1 wherein R 1 is ethyl.
13. The process according to claim 1 wherein R 2 is ethyl.
14. The process according to claim 1 wherein Hal is chlorine.
15. The process according to claim 1 wherein Hal is bromine.