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
  • C07C45/51—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by pyrolysis, rearrangement or decomposition
  • C07C45/54—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by pyrolysis, rearrangement or decomposition of compounds containing doubly bound oxygen atoms, e.g. esters

Definitions

• the present invention relates to the rearrangement of dimethylphenyl- acylates.
• hydroxyaryl ketones in particular hydroxyacetophenones, and their derivatives bearing methyl groups on the aromatic ring are of great interest for many industrial applications. Such compounds are useful in the fields pharmaceutical, agricultural, animal and human nutrition, and perfumery industry, and in the manufacturing of polymeric materials, either as final compounds or as key intermediates.
• hydroxyaryl ketones are important synthons and intermediates in organic synthesis. Examples of such molecules that can be derived from hydroxyaryl ketones are the fungicide Metrafenone, the anti- spasmodic agent Flopropione, the anti-arrhythmic agent Propafenone, the vasodilator Etafenone and the anti-bacterial Aspidinol and their derivatives.
• hydroxyaryl ketones having two methyl groups bound to the aromatic ring.
• the Fries rearrangement of substituted phenyl esters generally leading to the formation of o- and p-hydroxy ketones is the most common and suitable process. See, for example: R. Martin, Organic Preparations and Procedures International, vol. 24(4), pp. 369-435 (1992); R. Martin, “Flandbook of Flydroxyacetophenones”, Kluwer Academic Publishers, Dordrecht, The Netherlands, (1997).
• the Fries rearrangement can by catalyzed by the use of Lewis or Bnzsnsted acids.
• the problem to be solved by the present invention is to offer a process for the formation of specific hydroxyaryl ketones having two methyl groups bound to the aromatic ring.
• the present invention relates to a process for the manufacturing a compound of the formula (I) by a rearrangement of a compound of formula (II) wherein
• R 1 and R 2 and R 3 represent either FI or CFh; with the proviso that exactly two of the substituents R 1 or R 2 or R 3 represent CFh; and
• R represents a C 1 -3 alkyl group, preferably a linear C 1 -3 alkyl group; characterized in that the rearrangement is performed in the presence of a zeolite having either the FAU framework structure or the *BEA framework structure.
• a “C x-y -alkyl” group is an alkyl group comprising x to y carbon atoms, i.e. , for example, a C-i- 3 -alkyl group is an alkyl group comprising 1 to 3 carbon atoms.
• the alkyl group can be linear or branched.
• -CFI(CFl3)-CFl 2 -CFl3 is considered as a C 4 -alkyl group.
• a respective dimethyl phenyl acylate having the position of the methyl groups at the 3 and 5 position such as 3,5-dimethylphenyl acetate
• R represents a methyl group.
• R 1 , R 2 and R 3 are preferred are the following combination of R 1 , R 2 and R 3 :
• the compounds of the formula (II) are known to the person skilled in the art and can be easily manufactured. Typically, the compounds of the formula (II) can be synthesized by esterification of the respective phenol (formula (ll-A)) with a suitable esterification agent (EA), such as the respective acyl halide or carboxylic acid anhydride:
• the compound of the formula (II) are 2,3-dimethylphenyl acetate, 2,4-dimethylphenyl acetate or 3,4-dimethylphenyl acetate, most preferred 2,3-dimethylphenyl acetate.
• Zeolites are known to be aluminosilicate minerals than can exhibit micro-, meso- and macro-porosity arising depending on their type and form. There exists a huge variety of natural and artificial zeolites which are classified by the
• IZA International Zeolite Association
• zeolites of a different framework are not or significantly less suited for the rearrangement reactions.
• Zeolyst International and Clariant offer commercially suitable zeolites having either the FAU framework structure or the *BEA framework structure, particularly suitable are the commercial zeolites CP814E, CBV30, CBV712, CBV720, CBV780 from Zeolyst International, and HCZB30, HCB150 from Clariant.
• zeolite having the FAU framework structure is CBV720, CBV780 from Zeolyst International.
• Preferred zeolite having the *BEA framework structure is FICZB30 from Clariant.
• the zeolites having the FAU framework structure or the *BEA framework structure have preferably a molar ratio of Si: Al in the range between 5 and 100, preferably between 6 and 60, more preferably between 10 and 45.
• zeolites having the FAU framework structure.
• the zeolites are preferably heated in air at a temperature of at least 400°C, preferably at least 500°C, for an extended time period of at least 4 hours, preferably at least 5 hours, prior to their use in the said process for manufacturing the compound of formula (I).
• the molar amount of the compound of the formula (II) is preferably in the range of 0.5 to 50 mmol, preferably 2 to 20 mmol, more preferably 5 to 10 mmol, per gram of the zeolite.
• the rearrangement reaction can be performed using the compound of formula (II) in neat or in a suitable solvent.
• the rearrangement is performed without a solvent.
• the rearrangement is performed in the presence of a solvent being selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons, nitrated aliphatic hydrocarbons and nitrated aromatic hydrocarbons, preferably selected from the group consisting of C5- 12 alkanes, C6- 12 cycloalkanes and benzene carrying at least one C 1-4 alkyl group and/or at least one nitro group.
• a solvent being selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons, nitrated aliphatic hydrocarbons and nitrated aromatic hydrocarbons, preferably selected from the group consisting of C5- 12 alkanes, C6- 12 cycloalkanes and benzene carrying at least one C 1-4 alkyl group and/or at least one nitro group.
• Particularly preferred as such suitable and preferred solvents are the solvents selected from the group consisting of toluene, n-decane, n-hexane, and nitrobenzene.
• the solvent is anhydrous.
• the rearrangement reaction is typically performed in a reaction capable of withstanding elevated pressures, such as a pressure tube reactor an autoclave.
• the rearrangement is performed at a temperature in the range of 80 - 300 °C, particularly of 100 - 200 °C, most preferably of 120 - 180 °C.
• the rearrangement is performed under an inert gas atmosphere, particularly under nitrogen or a noble gas atmosphere.
• the selectivity in the formation of the compound of the formula (I) is preferably higher than 44 %, more preferably higher than 60 %, most preferably higher than 70%.
• ester hydrolysis product i.e. phenol of formula (ll-A)
• the conversion is preferably at least 60%, more preferably higher than 65 %, even more preferably higher than 70 %, most preferably at least 90 %.
• the zeolite can be easily separated from the product of the above process, i.e. the compound of the formula (I) can be easily isolated.
• the invention relates to the starting mixture, i.e. the composition comprising at least
• composition particularly for compound of formula (II) as well for the zeolite have been disclosed in great detail when discussing above the process for the manufacturing a compound of the formula (I).
• This composition is suitable for the above rearrangement reaction to form compound of the formula (I).
• the invention relates also to the product mixture, i.e. the mixture after the rearrangement reaction, i. e. the composition comprising at least
• zeolite having either the FAU framework structure or the *BEA framework structure. Details for said composition, particularly for compound of formula (I) as well for the zeolite have been disclosed in great detail when discussing above the process for the manufacturing a compound of the formula (I).
• the compound of formula (I) can be easily isolated from this composition and can be used for further purposes.
• zeolite having either the FAU framework structure or the *BEA framework can be used for the chemical transformation reaction of a compound the formula (II) which leads to the formation of compound of formula (I).
• the present invention relates to the use of a zeolite having either the FAU framework structure or the *BEA framework structure in a chemical transformation reaction of a compound the formula (II).
• the present invention is further illustrated by the following experiments.
• All zeolites have a molar ratio of Si: Al of approximately 15.

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• 2021
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