Claims
- 1. A process for the preparation of an indenonecarboxylic acid of the formula I ##STR42## in which R.sup.3 is Cl or Br, and R, R.sup.1 and R.sup.2 are identical or different and R is a n-alkyl radical having 1 to 4 C atoms, or is H, Cl, Br or F, R.sup.1 is a n-alkyl radical having 1 to 4 C atoms, or is H, and R.sup.2 is H or CH.sub.3, or R.sup.1 and R.sup.2 together are the group --CH.sub.2 CH.sub.2 CH.sub.2 --, in which latter case the bond to the six-membered ring is via the C atoms in the 5-position and 6-position of the nucleus, which comprises subjecting an aromatic compound of the formula II ##STR43## in which the H atoms on at least 2 adjacent C atoms of the nucleus have not been replaced by substituents and in which R, R.sup.1 and R.sup.2 are as defined for formula I, either together with a diahalogenomaleic anhydride of the formula III ##STR44## or together with an ester of the formula IV ##STR45## in which formulae R.sup.3 is as defined for formula I and R.sup.4 is in each case a low-molecular aliphatic radical, a cycloaliphatic radical, an aliphatic-aromatic radical or an aromatic radical, in each case in an approximately stoichiometric ratio, to a condensation reaction in the presence of AlCl.sub.3 and if desired in the presence of inert fluxes and/or solvents, at temperatures between 40.degree. and 150.degree. C., and hydrolysing the reaction product thus obtained.
- 2. A process according to claim 1, wherein the condensation reaction is carried out in 2 stages by preparing a keto-carboxylic acid of the formula V ##STR46## in the reaction mixture in the 1st stage, in a manner known per se, and isolating this acid and, in the 2nd stage, cyclising the ketoacid of the formula V, likewise in the presence of AlCl.sub.3 and if desired in the presence of inert fluxes and/or solvents, but at temperatures between 40.degree. and 150.degree. C., to give the corresponding indenonecarboxylic acid of the formula I, which is liberated from the resulting reaction mixture by hydrolysis.
- 3. A process according to claim 1, wherein a dihalogenomaleic anhydride or ester of the formula III or IV is used in which R.sup.3 is chlorine.
- 4. A process according to claim 1, wherein an ester of the formula IV is used in which R.sup.4 is an aliphatic radical having a total of 1 to 4 C atoms.
- 5. A process according to claim 1, wherein AlCl.sub.3 is used in an amount of at least 1 mol per mol of the dihalogenomaleic anhydride of the formula III or of the ester of the formula IV.
- 6. A process according to claim 1, wherein the condensation reaction is carried out in the presence of an inert solvent.
- 7. A process according to claim 6, wherein the condensation reaction is carried out in the presence of a dialkylamide of a low-molecular carboxylic acid as the solvent, the molar ratio of dialkylamide to AlCl.sub.3 being at least 1:1.
- 8. A process according to claim 1, wherein the condensation reaction is allowed to proceed in the presence of inert fluxes, the amounts being such that the melting point which results when the fluxes are mixed with the AlCl.sub.3 in the reaction mixture is lower than the reaction temperature.
- 9. A process according to claim 8, wherein the fluxes used are inorganic salts or organic fluxes or mixtures of the salts with the organic fluxes, the amounts being such that a lowering of the melting point of the salt mixture results when the fluxes are mixed with the AlCl.sub.3 in the reaction mixture.
- 10. A process according to claim 9, wherein the organic fluxes used are dialkylamides of low-molecular carboxylic acids, the molar ratio of dialkylamide to AlCl.sub.3 being within the limits 1:4 to 1:1.
- 11. A process according to claim 9, wherein the inorganic salts employed are NaCl and/or KCl, if desired together with dimethylformamide as an organic flux.
Parent Case Info
This is a Divisional of application Ser. No. 114,488, filed on Jan. 23, 1980, now abandoned.
US Referenced Citations (7)
Foreign Referenced Citations (6)
Number |
Date |
Country |
49-128991 |
Dec 1974 |
JPX |
49-128992 |
Dec 1974 |
JPX |
49-128993 |
Dec 1974 |
JPX |
50-5376 |
Jan 1975 |
JPX |
50-5377 |
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JPX |
50-77363 |
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JPX |
Non-Patent Literature Citations (3)
Entry |
T. Zincke et al, Ann. 283, 341 (1894). |
R. E. Lutz, J. Am. Chem. Soc. 52, 3404 (1930). |
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Divisions (1)
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Number |
Date |
Country |
Parent |
114488 |
Jan 1980 |
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