Process for preparing beta-ketoester compounds
The present invention relates to a process for preparing a beta-keto ester compound of formula (1), which is an intermediate for the synthesis of quinolone antibiotics. Particularly, the present invention is characterized by the reaction of an organo nitrile compound with a salt of mono-alkyl malonate in the presence of metal salt, and so the reaction is easy to control due to its endothermic nature, and is devoid of lachrymatory reagents with excellent reproducibility. Subsequent in situ hydrolysis in the presence of aqueous acid solution provided the compound of formula (1).
1. A process for preparing a beta-keto ester compound of formula (1):
wherein,
Q represents C—H, C—NO 2 , C—F, C—OMe or N,
X, Y and Z each independently represent H, halogen or NO 2 ,
R represents straight or branched C 1 -C 6 -alkyl or benzyl, and
M represents alkali metal, comprising the steps of,
1) obtaining a compound of formula (6) by reacting a compound of formula (2) with a compound of formula (3) in the presence of metal salt;
wherein Q, X, Y, Z and R are defined as above,
wherein Q, X, Y, and Z are defined as above, and
wherein R is defined as above and M represents alkali metal, and
2) hydrolyzing the compound obtained from step 1) in the presence of aqueous acid solution.
2. The process according to claim 1 , wherein the reaction is carried out by one-pot reaction.
3. The process according to claim 1 , wherein the reaction is carried out in one or more solvents selected from the group consisting of 1,2-dichloroethane, chloroform, toluene, N,N-dimethylformamide and N-methylpyrrolidinone.
4. The process according to claim 1 , wherein R is methyl, ethyl, isopropyl or t-butyl.
5. The process according to claim 1 , wherein M is lithium, sodium or potassium.
6. The process according to claim 1 , wherein the compound of formula (3) is used in 1˜2 equiv to the compound of formula (2).
7. The process according to claim 6 , wherein the compound of formula (3) is used in 1˜1.5 equiv to the compound of formula (2).
8. The process according to claim 1 , wherein the metal salt is nickel salt, copper salt, indium salt or zinc salt.
9. The process according to claim 1 or 8 , wherein the metal salt is selected from the group consisting of nickel chloride, nickel bromide, nickel acetylacetonate, copper chloride, copper bromide, copper iodide, copper acetylacetonate, indium chloride, indium bromide, indium iodide, zinc chloride, zinc bromide, zinc iodide, zinc acrylate, zinc methacrylate, zinc stearate and zinc acetylacetonate.
10. The process according to claim 1 or 8 , wherein the metal salt is used in 0.01˜1 equiv to the compound of formula (2).
11. The process according to claim 10 , wherein the metal salt is used in 0.5˜1 equiv to the compound of formula (2).
12. The process according to claim 1 , wherein the aqueous acid solution is an aqueous inorganic acid solution.
13. The process according to claim 12 , wherein the inorganic acid is hydrochloric acid or sulfuric acid.
14. The process according to claim 1 , wherein the hydrolyzing reaction is carried out at the temperature range of 20 to 100° C.
15. The process according to claim 14 , wherein the hydrolysis reaction is carried out at the temperature range of 80 to 90° C.
16. The process according to claim 1 , wherein the compound of formula (2) is prepared by chlorinating the hydroxyl group of a compound of formula (5):
wherein Q represents N; X represents F; Y and Z each represent Cl.
17. The process according to claim 16 , wherein the chlorination is carried out in the presence of 2˜10 equiv of phosphorus oxychloride, and 1˜10 equiv of phosphorus pentachloride, to the compound of formula (5).