Claims
- 1. A process for the preparation of a 4-acyl-3,5-cyclohexanedione-1-carboxylic acid derivative of formula I ##STR15## wherein A is an OR.sub.2 or --NR.sub.3 R.sub.4 radical or a metal or ammonium salt thereof,
- R.sub.1 is C.sub.1 -C.sub.6 alkyl or C.sub.3 -C.sub.6 cycloalkyl, each unsubstituted or substituted by halogen, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 alkylthio,
- R.sub.2, R.sub.3 and R.sub.4 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.2 -C.sub.10 alkoxyalkyl, C.sub.2 -C.sub.10 alkylthioalkyl; C.sub.3 -C.sub.6 alkenyl which is unsubstituted or substituted by halogen, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 alkylthio; C.sub.3 -C.sub.6 alkynyl; or phenyl wherein the phenyl nucleus is unsubstituted or substituted by halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 haloalkyl, nitro or cyano, and
- R.sub.3 and R.sub.4, together with the nitrogen atom to which they are attached, also form a 5- or 6-membered heterocyclic ring system which may contain an additional oxygen or sulfur atom in the ring, which process comprises combining, in an inert solvent, a reactive carboxylic acid derivative of formula III ##STR16## wherein X is a halogen atom, an alkylsulfonic or arylsulfonic acid radical or the molecular radical ##STR17## which is necessary to form an anhydride and R.sub.1 is as defined for formula I, and a metal cyanide, heating the reaction mixture to boiling point and, after cooling to a temperature in the range from 0.degree. C. to room temperature, adding in succession to said mixture a Lewis acid, an equimolar amount, with respect to the carboxylic acid derivative of formula III, of a 3,5-cyclohexanedione-1-carboxylic acid derivative of formula II ##STR18## wherein A is as defined for formula I, and, gradually, an organic base and, after acidifying the reaction mixture with an aqueous acid, isolating therefrom by extraction the 4-acyl-3,5-cyclohexanedione-1-carboxylic acid derivative of formula I.
- 2. A process according to claim 1, wherein the inert organic solvent is acetonitrile or a halogenated hydrocarbon.
- 3. A process according to claim 1, wherein the reactive carboxylic acid derivative of formula III is a halide.
- 4. A process according to claim 1, wherein the metal cyanide is an alkali metal cyanide or copper cyanide.
- 5. A process according to claim 1, which comprises heating the mixture of organic solvent, carboxylic acid derivative of formula II and metal cyanide for 1 to 25 hours under reflux before cooling to a temperature in the range from 0.degree. C. to room temperature and continuing the reaction sequence.
- 6. A process according to claim 1, wherein the Lewis acid is zinc chloride or aluminium chloride.
- 7. A process according to claim 1, wherein diethylamine, trimethylamine, triethylamine, .gamma.-picoline, 4-N,N-dimethylpyridine, 4-N,N-diethylpyridine, 4-pyrrolidinopyridine, N-methylimidazole or 4-ethylimidazole is added gradually as organic base to the reaction mixture.
- 8. A process according to claim 1, which comprises acidifying the reaction mixture with a mixture of hydrochloric acid and ice.
- 9. A process according to claim 1, wherein the reactive carboxylic acid derivative of formula III is the chloride.
Priority Claims (1)
Number |
Date |
Country |
Kind |
4734/84 |
Oct 1984 |
CHX |
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Parent Case Info
This is a continuation of application Ser. No. 778,109 filed on Sept. 20, 1985, abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (4)
Number |
Date |
Country |
2039466 |
Feb 1972 |
DEX |
2232730 |
Jan 1974 |
DEX |
58-164543 |
Sep 1983 |
JPX |
558319 |
Jan 1975 |
CHX |
Continuations (1)
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Number |
Date |
Country |
Parent |
778109 |
Sep 1985 |
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