Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
  • C07C45/49—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reaction with carbon monoxide

Definitions

• the present invention relates to a process for the preparation of aromatic aldehydes from halogenaphthalene compounds.
• aromatic is meant an aromaticity constituted by a naphthalene system.
• the invention relates more particularly to the preparation of 2-formyl-6-methoxynaphthalene.
• 2-formyl-6-methoxynaphthalene is an intermediate product which can be used in particular for the manufacture of 1- [2'-methoxynapht-6'-yl] butan-3-one represented by the following formula:
• FR-A-2 407 907 which is described in FR-A-2 407 907, as an anti-inflammatory and / or analgesic agent used for example for the treatment of rheumatism and arthritic affections.
• 2-bromo-6-methoxynaphthalene or bromoneroline is a product which can be used as the raw material of choice in the synthesis of 2-formyl-6-methoxynaphthalene.
• Another access route to aldehyde according to EP-A-415524 consists in reacting N-bromosuccinimide with 2-methyH5-methoxynaphthalene, in the presence of a radical initiator (aza / sobutyronrtrile) leading to a dibromation of the group methyl.
• the dibromed intermediate is subjected to hydrolysis which makes it possible to obtain on the order of 12% aldehyde.
• This radical bromination method is not very industrial and does not give satisfactory reaction yields.
• 6-methoxynaphthalene from 2-bromo- ⁇ -methoxynaphthalene, by hydroformylation catalyzed by a catalyst comprising a salt of formic acid, a palladium compound and a cation exchange resin
• the yield obtained is 63% but the reaction time is long (20 h) and there is formation of a by-product, 2-methoxynapht-6-oic acid which must be eliminated.
• the object of the present invention is precisely to propose a method enabling these drawbacks to be overcome.
• halogenaphthalene compound means more particularly a chlorine, bromine or fluorine atom, preferably a bromine atom.
• electro-donor group is meant a group as defined by H.C. BROWN in the work of Jerry MARCH - Advanced Organic Chemistry, chapter 9, pages 243 and 244 (1985).
• - X represents a halogen atom
• - R represents an electro-donor group
• - n represents the number of electron donor groups in the naphthalene system and is at least equal to 1
• - m represents the number of halogen atoms per cycle and is at least equal to i.
• naphthalene compound used corresponds to formula (I) in which at least one of the benzene nuclei of the naphthalene system carries at least one electron-donor group.
• n is preferably equal to 1 or 2.
• the naphthalene compound comprises at least one electron donor group, but the invention does not exclude the presence of other substituents.
• each benzene nucleus of the naphthalene system carries other substituents.
• the maximum number of substituents likely to be worn by each cycle is easily determined by a person skilled in the art.
• represents a linear or branched alkyl radical having from 1 to 6 carbon atoms and even more preferably from 1 to 4 carbon atoms or the phenyl radical
• R2 radicals represent a hydrogen atom, a linear or branched alkyl radical having from 1 to 6 carbon atoms and even more preferably from 1 to 4 carbon atoms or a phenyl radical,
• two radicals R and the two successive atoms of a benzene ring can be linked together by an alkylene, alkenylene or alkenylidene radical having from 2 to 4 carbon atoms to form a saturated, unsaturated heterocycle or aromatic having 5 to 7 carbon atoms.
• One or more carbon atoms can be replaced by another heteroatom, preferably oxygen.
• the radicals R can represent a methylenedioxy or ethylenedioxy radical.
• the compounds of formula (I) are chosen in which the radical (s) R represent a hydrogen atom, a hydroxyl group, an alkyl radical having from 1 to 4 carbon atoms, a methoxy radical, a methylene radical dioxy or ethylene dioxy.
• the radical (s) R represent a hydrogen atom, a hydroxyl group, an alkyl radical having from 1 to 4 carbon atoms, a methoxy radical, a methylene radical dioxy or ethylene dioxy.
• the halogen atoms carried by each cycle are generally identical, but the invention does not exclude that each cycle carries halogen atoms of different nature.
• the number of halogen atoms, m is most often 1 or 2 and preferably 1.
• the present invention applies very particularly to halogenaphthalene compounds corresponding to formula (I) in which the two halogen atoms are in position 1.6 and the electron-donor group is in position 2.
• the halogenaphthalene compound preferably used in the process of the invention is 1, 6-dibromo-2-methoxynaphthalene.
• a finely divided noble metal from group VIII of the periodic table of elements such as palladium, rhodium and iridium, or their salts, can be used for carrying out the process according to the invention.
• elements such as palladium, rhodium and iridium, or their salts.
• mineral or organic acids can be used for carrying out the process according to the invention.
• the preferred metal is palladium.
• the other metals although less active, may be of significant interest due to the high price of palladium.
• Palladium derivatives are particularly suitable for the process of the invention.
• palladium derivatives mention may be made of carboxylates such as in particular acetates, propionates, butyrates or benzoates of palladium (II), palladous chloride. It is also possible to use complexes of mineral or organic salts of palladium with phosphine.
• this complex is generally produced in situ between the palladium derivative and the phosphine present.
• the said complex can also be prepared extemporaneously and introduced into the reaction medium. It is then possible to add or not an additional quantity of free phosphine.
• Said coordinating agents are advantageously hydrocarbon derivatives of the elements of column V.
• Said hydrocarbon derivatives of the elements of column V derive from the valence III state of nitrogen such as amines, phosphorus such as phosphines, arsenic such as arsines and antimony such as stibines.
• hydrocarbon derivatives of the elements of column VB preferably of period greater than the 2nd, phosphorus such as phosphines.
• aliphatic, cycloaliphatic or arylaliphatic phosphines or mixed, aliphatic and / or cycloaliphatic and / or arylaliphatic and / or aromatic phosphines are used.
• phosphines are in particular those which correspond to the general formula
• radicals R3, R4 and R5 represent a phenyl radical or a phenyl radical substituted by one or more alkyl radicals having 1 to 4 carbon atoms or alkoxy radicals having 1 to 4 carbon atoms.
• phosphines there may be mentioned, without limitation: tricyclohexylphosphme, trimethylphosphine, triethylphosphine, tri-n-butylphosphine, triisobutylphosphine, tri-tert-butylphosphine, tribenzylphosphine, dicyclohexylphenylphosphine, dimethyl diethylphenylphosphine, di-ferf-butylphenylphosphine.
• R6 3 (HD in which: - the radicals Rg, identical or different, represent hydrocarbon radicals having from 1 to 20 carbon atoms, such as alkyl, cycloalkyl, aryl or heterocyclic radicals;
• Rg represent an alkyl radical having 1 to 10 carbon atoms and preferably 1 to 4 carbon atoms or a cyclopentyl or cyclohexyl ⁇ radical or a pyridinyl radical;
• triethylamine tri-r. propylamine, tri-n-butylamine, methyldibutylamine, methyldicyclohexylamine, pethyldiisopropylamine, NN-diethylcyclohexylamine, 4-dimethylamino pyridine, N-methylpiperidine, N-ethylpiperidine, Nt> butylpiperidine N-methylpyrrolidine, 1,2-dimethylpyrrolidine.
• the base can also be a strong mineral base or a relatively weak acid salt or a mixture of the above.
• HP0 4 is particularly favorable. Mention may also be made, as anions giving good results, of sulphate anions, acetate anions and trifluoroacetate anions.
• the quantity of catalyst expressed in moles of metal atoms or in moles of metal derivative per mole of halogenaphthalene compound of formula (I) can vary within wide limits.
• it can be between 10 " 5 and 10'1 mole / mole and preferably between 10 -4 and 10 " 2 mole / mole.
• the amount of free phosphine and / or in the form of a complex with the catalyst is such that the phosphine / noble metal molar ratio of the catalyst is at least equal to 1.
• the phosphine / noble metal ratio can reach values as high as 10,000.
• a phosphine / noble metal ratio of between 1 and 1,000 is generally very suitable. It is preferably chosen between 1 and 100.
• the quantity used is specified in the case of a tertiary year, but these values can be transposed by a person skilled in the art to any other base. .
• the amount of tertiary amine used must be sufficient to neutralize the hydracid released by the reaction.
• concentration of tertiary amine in the medium must be at least 2 moles per liter for the duration of the reaction.
• CO / H2 mixtures with different molar ratios of the two gases can be used.
• the CO / H2 molar ratio varies between 0.1 and 10.
• the reaction temperature is advantageously between 50 and 250 ° C, and preferably between 100 and 200 ° C.
• the pressure under which the process is carried out also varies very widely. Generally, it ranges from 0.1 to 30 MPa (1 to 300 bar) and preferably from 1 to 15 MPa (10 to 150 bar).
• An inert solvent may be used under the conditions of the hydrocarbonylation reaction.
• saturated aliphatic or cycloaliphatic hydrocarbons such as hexane or cyclohexane, or aromatic hydrocarbons such as benzene, toluene, xylenes; esters such as methyl benzoate, methyl terephthalate, methyl adipate, dibutyl phthalate; polyol esters or ethers such as tetraethylene glycol diacetate; cyclic ethers such as tetrahydrofuran or dioxane.
• the concentration of the halogenaphthalene compound of formula (I) used in the solvent can vary within very wide limits, until saturation under the operating conditions. Generally, it is not economically advantageous to use less than 5% by weight of halogenaphthalene compound per volume of solvent.
• the concentration by weight of halogenaphthalene compound per volume of solvent is between 5% and 50% and preferably between 10% and 40%.
• the process according to the invention can be carried out by introducing the halogenaphthalene compound of formula (I), the tertiary amine, the catalyst, the phosphine and the solvent into an inert autoclave, then, after the usual purges, by feeding the autoclave with an adequate pressure of a CO / H2 mixture; the contents of the autoclave are then brought under stirring to the appropriate temperature until absorption ceases.
• the pressure in the autoclave can be kept constant for the duration of the reaction by virtue of a reserve of gaseous mixture, which supplies it at the selected pressure.
• the autoclave is cooled and degassed.
• the reaction mixture is recovered.
• a simple washing of the organic phase with a dilute acid solution preferably an aqueous solution of dilute hydrochloric acid (for example from 5 to 20% by weight), makes it possible to remove the traces of amine.
• the aldehyde obtained can be purified, in particular by recrystallization from an aliphatic hydrocarbon, preferably hexane or heptane.
• the process can be carried out batchwise or continuously as indicated above by recycling the catalyst, the phosphine and the tertiary amine.
• 2-formyl-6-methoxynaphthalene is prepared from 1, 6-dibromo-2-methoxynaphthalene.
• the reactor is purged three times, with 10 bar of the H2 / CO mixture: 1/1 then pressurized to 25 bar at 25 ° C.
• the temperature is adjusted to 150 ° C and the back pressure to 40 bar; the progress of the reaction is followed by consumption of the gaseous mixture.
• the heating is stopped and the autoclave is cooled.
• the mass obtained is 2.59 g after drying under reduced pressure in a heated desiccator (10 mm of mercury, 50 ° C).
• the solid (crude reaction) is analyzed by high performance gradient liquid chromatography.
• the reactor is purged three times, with 10 bar of the H2 / CO mixture: 1/1 then pressurized to 25 bar at 25 ° C.
• the temperature is adjusted to 150 ° C and the back pressure to 40 bar; the progress of the reaction is followed by consumption of the gaseous mixture.
• the heating is stopped and the autoclave is cooled.
• the filtrate concentrated on a rotary evaporator leaves a yellow liquid which solidifies slowly at room temperature.
• the mass obtained is 3.72 g after drying under reduced pressure in a heated desiccator (10 mm of mercury, 50 ° C).
• the solid (crude reaction) is analyzed by high performance gradient liquid chromatography.

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• 1997
  • 1997-04-17 FR FR9704738A patent/FR2762314B1/fr not_active Expired - Fee Related
• 1998
  • 1998-04-15 EP EP98920624A patent/EP0975571A1/de not_active Withdrawn
  • 1998-04-15 WO PCT/FR1998/000759 patent/WO1998047848A1/fr not_active Application Discontinuation
  • 1998-04-15 JP JP54514598A patent/JP2001521543A/ja active Pending
  • 1998-04-15 AU AU73417/98A patent/AU7341798A/en not_active Abandoned

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