WO2012172120A2 - 2-(2,3-dimethylphenyl)-1-propanal and its use as perfume - Google Patents

2-(2,3-dimethylphenyl)-1-propanal and its use as perfume Download PDF

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Publication number
WO2012172120A2
WO2012172120A2 PCT/EP2012/070873 EP2012070873W WO2012172120A2 WO 2012172120 A2 WO2012172120 A2 WO 2012172120A2 EP 2012070873 W EP2012070873 W EP 2012070873W WO 2012172120 A2 WO2012172120 A2 WO 2012172120A2
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Prior art keywords
reaction
compound
formula
acid
xxi
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PCT/EP2012/070873
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French (fr)
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WO2012172120A3 (en
Inventor
Florencio Zaragoza Doerwald
Anna KULESZA
Stephan Elzner
Robert BUJOK
Zbigniew WROBEL
Krzysztof Wojciechowski
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Lonza Ltd
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Application filed by Lonza Ltd filed Critical Lonza Ltd
Priority to IN7982DEN2014 priority Critical patent/IN2014DN07982A/en
Priority to PCT/EP2012/072797 priority patent/WO2013011156A2/en
Priority to ES12784297.9T priority patent/ES2557638T3/en
Priority to EA201691508A priority patent/EA029130B1/en
Priority to AU2012285676A priority patent/AU2012285676B2/en
Priority to EA201400937A priority patent/EA025591B1/en
Priority to CA2866431A priority patent/CA2866431C/en
Priority to PT127842979T priority patent/PT2847157E/en
Priority to US14/386,020 priority patent/US9126915B2/en
Priority to JP2015510661A priority patent/JP5777840B2/en
Priority to EP12784297.9A priority patent/EP2847157B1/en
Priority to NZ700641A priority patent/NZ700641B2/en
Priority to MYPI2014002578A priority patent/MY165212A/en
Priority to PL12784297T priority patent/PL2847157T3/en
Priority to HUE12784297A priority patent/HUE026686T2/en
Priority to KR1020147029913A priority patent/KR101537204B1/en
Priority to SG11201405611SA priority patent/SG11201405611SA/en
Priority to CN201280072267.0A priority patent/CN104203893B/en
Priority to DK12784297.9T priority patent/DK2847157T3/en
Publication of WO2012172120A2 publication Critical patent/WO2012172120A2/en
Publication of WO2012172120A3 publication Critical patent/WO2012172120A3/en
Priority to TW102116031A priority patent/TWI531557B/en
Priority to CL2014002908A priority patent/CL2014002908A1/en
Priority to HK15100992.1A priority patent/HK1201060A1/en
Priority to HRP20151390TT priority patent/HRP20151390T1/en
Priority to CL2016001663A priority patent/CL2016001663A1/en

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    • 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
    • C07C45/56—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds
    • C07C45/57—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds with oxygen as the only heteroatom
    • C07C45/58—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds with oxygen as the only heteroatom in three-membered rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
    • C07C1/20—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
    • C07C1/20—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms
    • C07C1/24—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms by elimination of water
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/36—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring increasing the number of carbon atoms by reactions with formation of hydroxy groups, which may occur via intermediates being derivatives of hydroxy, e.g. O-metal
    • C07C29/38—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring increasing the number of carbon atoms by reactions with formation of hydroxy groups, which may occur via intermediates being derivatives of hydroxy, e.g. O-metal by reaction with aldehydes or ketones
    • C07C29/40—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring increasing the number of carbon atoms by reactions with formation of hydroxy groups, which may occur via intermediates being derivatives of hydroxy, e.g. O-metal by reaction with aldehydes or ketones with compounds containing carbon-to-metal bonds
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D233/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings
    • C07D233/54—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members
    • C07D233/56—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring carbon atoms
    • C07D233/58—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring carbon atoms with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring nitrogen atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
    • C07D303/02—Compounds containing oxirane rings
    • C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
    • C11B9/00—Essential oils; Perfumes
    • C11B9/0061—Essential oils; Perfumes compounds containing a six-membered aromatic ring not condensed with another ring
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2531/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • C07C2531/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • C07C2531/025—Sulfonic acids

Definitions

  • the invention discloses 2-(2,3-dimethylphenyl)-l-propanal, a method for its preparation from 1-bromo 2,3-dimethylbenzene and aceton, its use in perfumes and its use for the preparation of medetomidine.
  • Aromatic aldehydes are widely used as flavours and fragrances in cosmetics, perfumes, and numerous household products.
  • Alpha, beta-unsaturated aromatic aldehydes, such as substituted cinnamic aldehydes, are known to have distinct fragrance and are therefore used in the perfume industry
  • WO 98/45237 A discloses certain aromatic aldehydes, a method for producing them starting from acetophenone acetals, their use as perfumes and their use as intermediates for the preparation of 3-arylpropanals. They have a musky fragrance.
  • the perfume and household product industry has a constant need for new perfumes with interesting, new and not yet available fragrances in order to increase the available choice of fragrances and to adapt the fragrances to the ever changing demand of fashion. Furthermore the respective substances need to be synthesized economically and with consistent quality. High purity and strong fragrances are desired.
  • the present invention provides a new alpha, beta-unsaturated aromatic aldehyde, which has strong and interesting, aldehydic fragrance, intensely spicy and sweet, and an improved process for the production thereof.
  • halogen means F, CI, Br or I, preferably CI, Br or I;
  • alkyl means linear, branched, cyclic or cyclo alkyl; if not otherwise stated.
  • alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, norbornyl, adamantyl, and the like;
  • cyclic alkyl or “cyclo alkyl” are intended to include cyclo aliphatic, bicyclo aliphatic and tricycle aliphatic residues;
  • OTf trifluoromethanesulfonate also known as triflate
  • oxone mixture of 2 parts of KHS0 5 .with 1 part ofKHS0 4 .and 1 part of K 2 S0 4 ; salen ligand obtained from a condensation of salicylaldehyde or of a substituted salicylaldehyde derivative with ethylene diamine or with a substituted ethylene diamine;
  • step (N) comprises a reaction (N);
  • reaction (N) is a reaction of compound of formula (XXII) with a catalyst (N);
  • catalyst (N) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid,
  • camphorsulfonic acid HC1, HBr, H 2 S0 4 , HN0 3 , H 3 P0 4 , HC10 4 , BC1 3 , BBr 3 , BF 3 OEt 2 ,
  • BF 3 SMe 2 BF 3 THF, MgCl 2 , MgBr 2 , Mgl 2 , A1C1 3 , Al(0-alkyl) 3 , SnCl 4 , TiCl 4 , Ti(0- alkyl) 4 , ZrCl 4 , Bi 2 0 3 , BiCl 3 , ZnCl 2 , PbCl 2 , FeCl 3 , ScCl 3 , NiCl 2 , Yb(OTf) 3 , Yb(Cl) 3 , GaCl 3 , AlBr 3 , Ce(OTf) 3 , LiCl, Cu(BF 4 ) 2 , Cu(OTf) 2 , NiBr 2 (PPh 3 ) 2 , NiBr 2 , NiCl 2 ,
  • the Al(0-alkyl) 3 and the Ti(0-alkyl) 4 in the list of possible compounds for catalyst (N) are Al(0-Ci_ 4 alkyl) 3 and Ti(0-Ci_ 4 alkyl) 4 .
  • the acidic inorganic solid substance is aluminosilicates.
  • the acidic ion exchange resin is selected from the group consisting of copolymers of styrene and divinylbenzene and of perfluorinated branched or linear polyethylenes, these polymers being functionalized with S0 3 H groups;
  • the acidic ion exchange resin is selected from the group consisting of
  • the inorganic acid, with which the carbon was treated is selected from the group consisting of HC1, H 2 S0 4 and HN0 3 .
  • the catalyst (N) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, p-toluenesulfonic acid, HC1, HBr, H 2 S0 4 , H 3 P0 4 , BC1 3 , BF 3 OEt 2 , MgCl 2 , MgBr 2 , A1C1 3 , ZnCl 2 , Cu(BF 4 ) 2 , aluminosilicates, acidic ion exchange resins, carbon treated with HC1, H 2 S0 4 or HN0 3 ,and mixtures thereof; more preferably, the catalyst (N) is selected from the group consisting of acetic acid, formic acid, methanesulfonic acid, p-toluenesulfonic acid, HC1, H 2 S0 4 , BF 3 OEt 2 , Cu(BF 4 ) 2 , aluminosilicates
  • reaction (N) is done in a solvent (N);
  • solvent (N) is selected from the group consisting of water, tert-butanol, isopropanol,
  • acetonitrile preferably from water, acetonitrile, propionitrile, THF, 2-methyl-THF, 1,2-dimethoxyethane, dichloromethane, 1 ,2-dichloroethane, chloroform, toluene, cyclohexane, ethyl acetate, acetic acid, formic acid and mixtures thereof;
  • the catalyst (N) can be used in a pure form or as hydrate.
  • the catalyst (N) can be used as a solution in solvent (N).
  • the molar ratio between catalyst (N) and compound of formula (XXII) is from 1 : 1000 to 10: 1, more preferably from 1 : 100 to 5 : 1 , even more preferably from 1 :20 to 1 : 1, especially from 1 : 10 to 1 :2.
  • reaction temperature of reaction (N) is from -20 to 200 °C, more preferably from 0 to 150 °C, even more preferably from 10 to 100 °C.
  • the reaction (N) can be done in a system, that is closed or open to the atmosphere.
  • the pressure depends mainly on the boiling point of a solvent (N) and on the reaction temperature of reaction (N).
  • the reaction (N) is done at a pressure of from 0.01 bar to 20 bar, more preferably of from 0.1 to 10 bar, even more preferably of from atmospheric pressure to 5 bar.
  • reaction (N) is done in an open system.
  • reaction time of reaction (N) is from 30 min to 72 h, more preferably from 1 h to 48 h, even more preferably from 2 h to 24 h.
  • reaction (N) can be done as a continuous gas-phase reaction by passing the evaporated compound of formula (XXII) over the catalyst (N).
  • This gas-phase reaction can be done in the presence of an inert gas, the inert gas is preferably selected from the group consisting of nitrogen, a noble gas and carbon dioxide.
  • compound of formula (XXI) can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, filtration, crystallization, distillation, chromatography and any combination thereof, which are known per se to the person skilled in the art.
  • any volatile components of the reaction mixture or added or generated during work up can be removed by evaporation under reduced pressure.
  • reaction mixture resulting from reaction (N) or any aqueous phase during the work up after reaction (N) can be extracted with a solvent (M-extract),
  • solvent (M-extract) is preferably selected from the group consisting of water, toluene, benzene, xylene, chlorobenzene, dichloromethane, chloroform, acetic acid Ci_8 alkyl ester and combinations thereof;
  • the acetic acid Ci_8 alkyl ester is preferably an acetic acid Ci_ 4 alkyl ester, more preferably selected from the group consisting of ethyl acetate, isopropyl acetate and butyl acetate;
  • solvent (M-extract) is selected from the group consisting of toluene,
  • dichloromethane ethyl acetate, isopropyl acetate and mixtures thereof.
  • any washing of any organic phase after reaction (N) can be done with water, with a base (M-basify), with an aqueous solution of a base (M-basify), with an aqueous solution of an acid (M-acid) or with brine.
  • base (M-basify) is selected from the group consisting of NaHC0 3 , Na 2 C0 3 , NaOH and mixtures thereof.
  • base (M-basify) is added in such an amount, that the pH of the resulting mixture is from 7 to 12, more preferably from 8 to 10, even more preferably from 8 to 9.
  • acid (M-acid) is selected from the group consisting of oxalic acid, citric acid, maleic acid, fumaric acid, tartaric acid, NH 4 C1, HC1, HBr, H 2 S0 4 , H 3 P0 4 and mixtures thereof.
  • Any extraction or washing can be followed by filtration and concentration of the extract or of the washed mixture .
  • compound of formula (XXI) is purified after reaction (N) by chromatography. Any organic phase can be dried, preferably over MgS0 4 or Na 2 S0 4 .
  • Any concentration is preferably done by distillation, preferably under reduced pressure.
  • Compound of formula (XXI) can be obtained in step (N) as the aldehyde as depicted in formula (XXI), but also in form of its hydrate or hemiacetal.
  • the hemiacetal of compound of formula (XXI), which can result as product from step (N) can be the product of an addition reaction between the aldehyde as depicted in formula (XXI) and an alcohol selected from the group consisting of tert-butanol and isopropanol, or between the aldehyde as depicted in formula (XXI) and any alcohol which is used during the isolation after reaction (N).
  • formula (XXI) for the purpose of this invention encompasses the aldehyde, hydrate and the hemiacetal.
  • reaction (N) in form of its hydrate or of a hemiacetal
  • the hydrate or the hemiacetal can be converted into the aldehyde by standard reactions known to the person skilled in the art.
  • step (O) is prepared in a step (O) or in two steps, the two steps are step (01) and step (02); step (O) comprises a reaction (O);
  • reaction (O) is a reaction of compound of formula (XXIII), with a reagent (O);
  • gent (O) is selected from the group consisting of peracetic acid, trifluoroperacetic acid, perbenzoic acid, 3-chloroperbenzoic acid, monoperphthalic acid, dimethyldioxirane, tert- butylhydroperoxide, dibenzoyl peroxide, cumenehydroperoxide, oxygen, air, sodium hypochlorite, oxone, KHSO 5 , Na 2 0 2 , aqueous H 2 0 2 , H 2 0 2 dissolved in acetic acid, H 2 0 2 dissolved in trifluoroacetic acid, and mixtures thereof; step (01) comprises a reaction (01);
  • reaction (01) is a reaction of compound of formula (XXIII) with water and with a compound
  • step (02) comprises a reaction (02);
  • reaction (02) is a reaction of the reaction product from reaction (01) with a base (02);
  • base (02) is selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide and mixture thereof.
  • reagent (O) is selected from the group consisting of peracetic acid, tert- butylhydroperoxide, oxygen, air, sodium hypochlorite, aqueous H 2 0 2 , H 2 0 2 dissolved acetic acid, H 2 0 2 dissolved in trifluoroacetic acid, and mixtures thereof;
  • reagent (O) is aqueous H 2 0 2 .
  • reaction (O) is done in a solvent (O);
  • solvent (O) is selected from the group consisting of water, aqueous solutions of NaHC0 3 , Na 2 C0 3 , (NH 4 )HC0 3 , (NH 4 ) 2 C0 3 , KHC0 3 or K 2 C0 3 , benzene, toluene, NMP, dioxane, acetone, ethyl acetate, methylethylketone, tert-butanol, acetonitrile, chloroform, dichloromethane and mixtures thereof;
  • aqueous solutions of NaHC0 3 , Na 2 C0 3 , KHC0 3 or K 2 C0 3 , toluene, dioxane, acetone, ethyl acetate, methylethylketone, tert-butanol, acetonitrile,
  • Reaction (O) can be done in the presence of a catalyst (O);
  • catalyst (O) is selected from the group consisting of trifluoroacetic acid, trifluoroacetone, Mn(salen) complex, aldehydes, N-methylmorpholine N-oxide, 2,2,6, 6-tetramethylpiperidine 1-oxyl and mixtures thereof;
  • aldehydes are preferably isobutyraldehyde or benzaldehyde.
  • Reaction (O) can be done in the presence of a buffer (O);
  • buffer (O) is an aqueous buffer and is selected from the group consisting of K 2 C0 3 / EDTA-Na 2 buffer, phosphate buffer and other buffers known by the skilled person;
  • buffer (O) is an K 2 C0 3 / EDTA-Na 2 buffer.
  • reaction temperature of reaction (O) is from -20 to 100 °C, more preferably from -10 to 80 °C, even more preferably from 0 to 50 °C.
  • the reaction (O) can be done in a system, that is closed or open to the atmosphere.
  • the pressure depends on the boiling point of a solvent (O) and on the
  • the reaction (N) is done at a pressure of from 0.01 bar to 20 bar, more preferably of from 0.1 to 10 bar, even more preferably of from atmospheric pressure to 5 bar.
  • reaction (O) is done in an open system.
  • reaction time of reaction (O) is from 30 min to 72 h, more preferably from 1 h to 48 h, even more preferably from 2 h to 24 h.
  • reaction (O) the compound of formula (XXII) can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, crystallization, distillation, chromatography and any combination thereof.
  • reaction (01) and reaction (02) are conducted in solvent (O), with solvent (O) as defined above, also with all its preferred embodiments.
  • reaction temperatures of reaction (01) and of reaction (02) are identical or different and independently from each other from -20 to 100 °C, more preferably from -10 to 80 °C, even more preferably from 0 to 50 °C.
  • Reaction (01) and reaction (02) can independently from each other be done in systems, that are closed or open to the atmosphere.
  • the pressure depends on the boiling point of a solvent (O) and on the reaction temperature of reaction (01) and reaction (O) respectively.
  • reaction (01) and reaction (02) are independently from each other done at pressures of from 0.01 bar to 20 bar, more preferably of from 0.1 to 10 bar, even more preferably of from atmospheric pressure to 5 bar.
  • reaction (01) and reaction (02) are done in a open system.
  • reaction times of reaction (01) and of reaction (02) are independently from each other from 30 min to 72 h, more preferably from 1 h to 48 h, even more preferably from 2 h to 24 h.
  • reaction product of reaction (01) and the compound of formula (XXII) from reaction (02) can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, filtration, crystallization, distillation,
  • Reaction (01) and reaction (02) can be done consecutively without isolation of the reaction product of reaction (01), they can be done in one pot.
  • step (N) is done directly after step (O) or step (02) respectively in one pot.
  • catalyst (N) is simply added to the reaction mixture resulting from reaction (O) or from reaction (02) respectively.
  • compound of formula (XXIII) is prepared in a step (P);
  • step (P) comprises a reaction (P); in reaction (P) the compound of formula (XXIV) is exposed to a temperature (P);
  • temperature (P) is from 5 to 200 °C, more preferably from 100 to 150 °C.
  • Reaction (P) can be done in a solvent (P);
  • solvent (P) is selected from the group consisting of benzene, toluene, xylene, hexane, heptane, 1 ,2-dichloroethane, NMP, dichloromethane, chloroform and mixtures thereof;
  • benzene preferably from benzene, toluene, xylene, dichloromethane and mixtures thereof.
  • reaction (P) is done in the presence of a catalyst (P);
  • catalyst (P) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid,
  • camphorsulfonic acid HC1, HBr, H 2 S0 4 , KOH, NaOH, KHS0 4 , HN0 3 , H 3 P0 4 , HC10 4 , BC1 3 , BBr 3 , BF 3 OEt 2 , BF 3 SMe 2 , BF 3 THF, MgCl 2 , MgBr 2 , Mgl 2 , A1C1 3 , Al(0-alkyl) 3 , 1 2 , A1 2 0 3 , SnCl 4 , TiCl 4 , Ti(0-alkyl) 4 , ZrCl 4 , Bi 2 0 3 , BiCl 3 , ZnCl 2 , PbCl 2 , FeCl 3 , Yb(OTf) 3 , Yb(Cl) 3 , GaCl 3 , AlBr 3 , Ce(OTf) 3 , LiCl, acidic insoluble inorganic solid, acidic
  • methanesulfonic acid preferably from methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, H 2 S0 4 , KHS0 4 , H 3 P0 4 , acidic insoluble inorganic solid, acidic ion exchange resins, carbon treated with an inorganic acid, and mixtures thereof.
  • the Al(0-alkyl) 3 and the Ti(0-alkyl) 4 in the list of possible compounds for catalyst (P) are Al(0-Ci_ 4 alkyl) 3 and Ti(0-Ci_ 4 alkyl) 4 .
  • the acidic insoluble inorganic solid is acidic aluminosilicates or silica gel.
  • the inorganic acid, with which the carbon was treated is selected from the group consisting of HC1, H 2 S0 4 and HN0 3 .
  • the acidic ion exchange resin is selected from the group consisting of copolymers of styrene and divinylbenzene and of perfluorinated branched or linear polyethylenes, these polymers being functionalized with SO 3 H groups;
  • the acidic ion exchange resin is selected from the group consisting of
  • temperature (P) is preferably from 0 to 200 °C, more preferably from 10 to 150 °C, even more preferably from 10 to 100 °C.
  • Reaction (P) can be done in gas phase by passing evaporated compound of formula (XXIV) through a heated tube, the heated tube can be charged with a catalyst (P).
  • the compound of formula (XXIII) can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, crystallization, distillation, chromatography and any combination thereof.
  • step (Ql) comprises a reaction (Ql) by a reaction of compound of formula (XXV) with a reagent (Ql);
  • Q is Br, CI, or I
  • reagent (Q 1 ) is selected from the group consisting of lithium, magnesium, aluminum, zinc, calcium, isopropylmagnesium chloride, isopropylmagnesium bromide, butyllithium, sec- butyllithium and mixtures thereof
  • step (Q2) comprises a reaction (Q2)
  • reaction (Q2) is a reaction of the reaction product of reaction (Ql) with acetone; in step (Q3) comprises a reaction (Q3);
  • reaction (Q3) is a reaction of the reaction product of reaction (Q2) with a reagent (Q3); reagent (Q3) is selected from the group consisting of water, methanol, ethanol, oxalic acid, citric acid, NH 4 C1, HCl, HBr, HN0 3 , H 2 S0 4 , H 3 P0 4 , acetic acid, propionic acid, formic acid and mixtures thereof.
  • Q is Br.
  • reagent (Ql) is selected from the group consisting of lithium, magnesium, aluminum, isopropylmagnesium chloride, isopropylmagnesium bromide and mixtures thereof.
  • Reaction (Ql) can be catalyzed with a catalyst (Ql).
  • Catalyst (Ql) is selected from the group consisting of iodine, 1 ,2-dibromoethane, TiCl 4 , A1C1 3 , PbCl 2 , BiCl 3 , LiCl and mixtures thereof.
  • reagent (Q3) is water or aqueous NH 4 C1.
  • reaction (Ql) is performed in a solvent (Ql).
  • reaction (Q2) is performed in a solvent (Q2).
  • reaction (Q3) is performed in a solvent (Q3).
  • solvent (Ql), solvent (Q2) and solvent (Q3) are identical or different and
  • solvent (Ql), solvent (Q2) and solvent (Q3) are identical.
  • reaction temperatures of reaction (Ql), of reaction (Q2) and of reaction (Q3) are identical or different and idependently from each other preferably from -100 to 150 °C, more preferably from -60 to 100 °C, and even more preferably from -20 to 80 °C.
  • Reaction (Ql), reaction (Q2) and reaction (Q3) can be done at a constant temperature, or the temperature may be modified during the progress of the reactions. For instance, the reactions can run for a certain time at first temperature, and then for a subsequent time at a second temperature different from the first temperature. Alternatively, the temperature may be modified continuously during the reaction.
  • reaction times of reaction (Ql), of reaction (Q2) and of reaction (Q3) are identical or different and idependently from each other preferably from 30 min to 48 h, more preferably from 1 to 24 h, even more preferably from 2 to 12 h.
  • the amounts of solvent (Ql), of solvent (Q2) and of solvent (Q3) are identical or different and idependently from each other preferably from 2 to 40 fold, more preferably from 3 to 10 fold, even more preferably from 5 to 7 fold, of the weight of compound of formula (XXV), of the weight of the reaction product of reaction (Ql) and of the weight of the reaction product of reaction (Q2) respectively.
  • reagent (Ql) from 1.0 to 10 mol equivalents, more preferably from 1.1 to 5 mol equivalents, even more preferably from 1.1 to 3 mol equivalents of reagent (Ql) are used, the mol equivalents being based on the mol of compound of formula (XXV).
  • mol equivalents from 1.0 to 10 mol equivalents, more preferably from 1.1 to 5 mol equivalents, even more preferably from 1.1 to 3 mol equivalents of acetone are used, the mol equivalents being based on the mol of compound of formula (XXV).
  • mol equivalents being based on the mol of compound of formula (XXV).
  • reagent (Q3) is used, the mol equivalents being based on the mol of compound of formula (XXV) or of the mol of the reaction product of reaction (Q2).
  • reaction (Ql), reaction (Q2) and reaction (Q3) are done at atmospheric pressure.
  • reaction (Ql), reaction (Q2) and reaction (Q3) are done under inert atmosphere.
  • the inert atmosphere is achieved by the use if an inert gas selected from the group consisting of argon, another noble gas, lower boiling alkane, nitrogen and mixtures thereof.
  • the lower boiling alkane is preferably a Ci_ 3 alkane, i.e. methane, ethane or propane.
  • reaction product of reaction (Ql), the reaction product of reaction (Q2) and compound of formula (XXIV) respectively can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, crystallization, distillation, chromatography and any combination thereof.
  • reaction product of reaction (Ql) and the reaction product of reaction (Q2) are not isolated.
  • reaction (Ql), reaction (Q2) and reaction (Q3) are done consecutively; preferably, reaction (Ql), reaction (Q2) and reaction (Q3) are done in one pot.
  • reaction (Ql) and reaction (Q2) can be done in one pot by adding reagent (Ql) to a mixture of compound of formula (XXV) and acetone in a solvent (Ql); reaction (Q3) is done thereafter, preferably in the same pot.
  • Compound of formula (XXIV) is preferably isolated using conventional methods, such as evaporation of volatile components, hydrolysis and optional acidification of the higher- boiling residue, extraction, and distillation. Any aqueous phase can be extracted, preferably the extraction is done with a solvent (Q- extract).
  • Solvent (Q-extract) is benzene, toluene, ethyl acetate, or isopropyl acetate.
  • Any organic phase can be dried, preferably with magnesium sulphate.
  • Any concentration is preferably done by distillation, preferably under reduced pressure.
  • the compound of formula (XXIV) can be purified, preferably by crystallization or distillation under reduced pressure.
  • Compounds of formula (XXI) and (XXII) are chiral compounds, and the formulae comprise any enantiomer as well as any mixture of enantiomers of the compounds of formula (XXI), or of formula (XXII) respectively.
  • Compounds of formula (XXV) are known compounds and can be prepared according to known methods.
  • LCMS Chromatography Mass Spectrometry
  • TLC Thin Layer Chromatography
  • any organic phase can be dried, preferably over MgS0 4 or Na 2 S0 4 , if not stated otherwise.
  • Further subject of the invention is compound of formula (XXI), hydrate of compound of formula (XXI) and hemiacetal of compound of formula (XXI), the hemiacetal of compound of formula (XXI) being a product of an addition reaction between compound of formula (XXI) and an alcohol selected from the group consisting of tert-butanol and isopropanol.
  • subject of the invention is compound of formula (XXI).
  • compound of formula (XXI) as a fragrance, preferably in perfumes or house hold products.
  • Medetomidine is compound of formula (XX)
  • alpha2 adrenergic agonist which is currently being used as veterinary sedative and analgesic and is evaluated as anesthetic.
  • WO201 1/070069A discloses a process for the preparation of medetomidine, in which the imidazole ring is built up during a multi-step process starting from commercially affordable 2,3-dimethyl benzoic acid.
  • Compound of formula (XX) is preferably prepared from compound of formula (XXI) by a method, that comprises a reaction (Ml);
  • reaction (Ml) is a reaction between a compound of formula (XXI), an isocyanide and a compound acting as nitrogen source;
  • the isocyanide is preferably a reagent (M), reagent (M) is selected from the group consisting of p-toluenesulfonylmethyl isocyanide, trifluoromethanesulfonylmethyl isocyanide, methanesulfonylmethyl isocyanide, benzenesulfonylmethyl isocyanide, 4- acetamidobenzenesulfonylmethyl isocyanide and mixtures thereof;
  • M reagent
  • M is selected from the group consisting of p-toluenesulfonylmethyl isocyanide, trifluoromethanesulfonylmethyl isocyanide, methanesulfonylmethyl isocyanide, benzenesulfonylmethyl isocyanide, 4- acetamidobenzenesulfonylmethyl isocyanide and mixtures thereof;
  • the compound acting as a nitrogen source is preferably a reagent (M-A), reagent (M-A) is selected from the group consisting of ammonia, sulfamic acid, p-toluenesulfonamide, benzenesulfonamide, 4-acetamidobenzenesulfonamide, tritylamine, formamide, urea, urotropine, ethyl carbamate, acetamide and mixtures thereof;
  • M-A reagent
  • M-A is selected from the group consisting of ammonia, sulfamic acid, p-toluenesulfonamide, benzenesulfonamide, 4-acetamidobenzenesulfonamide, tritylamine, formamide, urea, urotropine, ethyl carbamate, acetamide and mixtures thereof;
  • solvent (M) is selected from the group consisting of ⁇ , ⁇ -dimethylformamide, Ci_ 6 alkanol, formamide, 1 ,2- dimethoxyethane, NMP, toluene, acetonitrile, propionitrile, ethyl carbamate, N,N- dimethylacetamide, water, acetamide and mixtures thereof.
  • reaction (M) Any sequence of the reaction of reagent (M) and of reagent (M-A) with the compound of formula (XXI) in reaction (Ml) can be used:
  • compound of formula (XXI) can first be reacted with reagent (M) and then reagent (M-A) added;
  • compound of formula (XXI) can first be first reacted with reagent (M-A) and then reagent (M) added;
  • compound of formula (XXI) can simultaneously be reacted with reagent (M) and with reagent (M-A), this embodiment is preferably suited for the case that reagent (M-A) and solvent (M) are identical and are formamide, ethyl carbamate or acetamide; preferably formamide.
  • the product is distinguished by a very special fragrance sought after in the fragrance industry.
  • EI Electron ionization mass spectra (70 eV), they were obtained on an AMD-604 spectrometer.
  • THF was distilled from sodium/benzophenone ketyl prior to use; the obtained anhydrous THF is called "dry THF" in the following text.
  • Example 1 2-(2,3-Dimethylphenyl)propan-2-ol, compound of formula (XXIV), prepared via an organomagnesium intermediate
  • the l-bromo-2,3- dimethylbenzene solution (1.0 mL) was added via a dropping funnel and the reaction was initiated by the addition of 1 ,2-dibromoethane (3 drops), and then the rest of the l-bromo-2,3- dimethylbenzene solution was added.
  • the content of the dropping funnel was added at such a rate to maintain slight reflux.
  • the mixture was refluxed for 1 h and then cooled to 0 °C.
  • a solution of dry acetone (4.2 mL, 58 mmol) in dry THF (15 mL) was added dropwise and the mixture was stirred at a temperature between 0 and 20 °C for 3 h.
  • a buffer was prepared by dissolving K 2 C0 3 (20.7 g) and EDTA-Na 2 (11.5 mg) in water (100 mL).
  • l,2-Dimethyl-3-(2-propenyl)benzene, compound of formula (XXIII), prepared according to example 3 (0.90 g, 6.16 mmol) was dissolved in a mixture of dichloromethane and acetonitrile (v/v 1 : 1 , 60 mL), and the buffer prepared as described above (9.3 mL) was added.

Abstract

The invention discloses 2-(2,3-dimethylphenyl)-1-propanal, a method for its preparation from -bromo 2,3-dimethylbenzene and aceton, its use in perfumes and its use for the preparation of medetomidine.

Description

2-(2,3-DIMETHYLPHENYL)-l-PROPANAL AND ITS USE AS PERFUME
The invention discloses 2-(2,3-dimethylphenyl)-l-propanal, a method for its preparation from 1-bromo 2,3-dimethylbenzene and aceton, its use in perfumes and its use for the preparation of medetomidine.
Aromatic aldehydes are widely used as flavours and fragrances in cosmetics, perfumes, and numerous household products. Alpha, beta-unsaturated aromatic aldehydes, such as substituted cinnamic aldehydes, are known to have distinct fragrance and are therefore used in the perfume industry
WO 98/45237 A discloses certain aromatic aldehydes, a method for producing them starting from acetophenone acetals, their use as perfumes and their use as intermediates for the preparation of 3-arylpropanals. They have a musky fragrance.
The perfume and household product industry has a constant need for new perfumes with interesting, new and not yet available fragrances in order to increase the available choice of fragrances and to adapt the fragrances to the ever changing demand of fashion. Furthermore the respective substances need to be synthesized economically and with consistent quality. High purity and strong fragrances are desired. The present invention provides a new alpha, beta-unsaturated aromatic aldehyde, which has strong and interesting, aldehydic fragrance, intensely spicy and sweet, and an improved process for the production thereof.
In the following text,
halogen means F, CI, Br or I, preferably CI, Br or I;
"alkyl" means linear, branched, cyclic or cyclo alkyl; if not otherwise stated. Examples of
"alkyl" include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, norbornyl, adamantyl, and the like;
"cyclic alkyl" or "cyclo alkyl" are intended to include cyclo aliphatic, bicyclo aliphatic and tricycle aliphatic residues;
Ac acetyl;
tBu tertiary butyl;
DBU 1 , 8-diazabicyclo [5.4.0]undec-7-ene; DABCO 1 ,4-diazabicyclo[2.2.2]octane;
DIPEA N-ethyl-N,N-diisopropylamine;
DMA N,N-dimethylacetamide;
DMF N,N-dimethylformamide;
EDTA-Na2 ethylene diamine tetraacetic acid disodium;
hexanes mixture of isomeric hexanes;
NMP N-methyl-2-pyrrolidone;
OTf trifluoromethanesulfonate, also known as triflate;
oxone mixture of 2 parts of KHS05.with 1 part ofKHS04.and 1 part of K2S04; salen ligand obtained from a condensation of salicylaldehyde or of a substituted salicylaldehyde derivative with ethylene diamine or with a substituted ethylene diamine;
sulfamic acid HO-S02-NH2;
TEMPO 2,2,6,6-tetramethylpiperidine 1-oxyl;
THF tetrahydrofuran;
xylene 1 ,2-dimethylbenzene, 1,3-dimethylbenzene, 1 ,4-dimethylbenzene or a mixture thereof;
if not otherwise stated.
Subject of the invention is a compound of formula (XXI).
Figure imgf000003_0001
Further subject of the invention is a method for preparation of compound of formula (XXI); the method comprises a step (N);
step (N) comprises a reaction (N);
reaction (N) is a reaction of compound of formula (XXII) with a catalyst (N);
Figure imgf000004_0001
catalyst (N) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid,
camphorsulfonic acid, HC1, HBr, H2S04, HN03, H3P04, HC104, BC13, BBr3, BF3OEt2,
BF3SMe2, BF3THF, MgCl2, MgBr2, Mgl2, A1C13, Al(0-alkyl)3, SnCl4, TiCl4, Ti(0- alkyl)4, ZrCl4, Bi203, BiCl3, ZnCl2, PbCl2, FeCl3, ScCl3, NiCl2, Yb(OTf)3, Yb(Cl)3, GaCl3, AlBr3, Ce(OTf)3, LiCl, Cu(BF4)2, Cu(OTf)2, NiBr2(PPh3)2, NiBr2, NiCl2,
Pd(OAc)2, PdCl2, PtCl2, InCl3, acidic inorganic solid substance, acidic ion exchange resin, carbon treated with inorganic acid and mixtures thereof.
Preferably, the Al(0-alkyl)3 and the Ti(0-alkyl)4 in the list of possible compounds for catalyst (N) are Al(0-Ci_4 alkyl)3 and Ti(0-Ci_4 alkyl)4.
Preferably, the acidic inorganic solid substance is aluminosilicates.
Preferably, the acidic ion exchange resin is selected from the group consisting of copolymers of styrene and divinylbenzene and of perfluorinated branched or linear polyethylenes, these polymers being functionalized with S03H groups;
more preferably, the acidic ion exchange resin is selected from the group consisting of
copolymers of styrene and divinylbenzene containing more than 5% of divinylbenzene, preferably being macroreticular, and of perfluorinated polyethylenes, these polymers being functionalized with S03H groups. Preferably, the inorganic acid, with which the carbon was treated, is selected from the group consisting of HC1, H2S04 and HN03.
Preferably, the catalyst (N) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, p-toluenesulfonic acid, HC1, HBr, H2S04, H3P04, BC13, BF3OEt2, MgCl2, MgBr2, A1C13, ZnCl2, Cu(BF4)2, aluminosilicates, acidic ion exchange resins, carbon treated with HC1, H2S04 or HN03,and mixtures thereof; more preferably, the catalyst (N) is selected from the group consisting of acetic acid, formic acid, methanesulfonic acid, p-toluenesulfonic acid, HC1, H2S04, BF3OEt2, Cu(BF4)2, aluminosilicates, acidic ion exchange resins, and mixtures thereof.
Preferably, reaction (N) is done in a solvent (N);
solvent (N) is selected from the group consisting of water, tert-butanol, isopropanol,
acetonitrile, propionitrile, THF, methyl-THF, NMP, dioxane, 1,2-dimethoxyethane, dichloromethane, 1 ,2-dichloroethane, chloroform, toluene, benzene, chlorobenzene, hexane, cyclohexane, ethyl acetate, acetic acid, formic acid, trifluoroacetic acid and mixtures thereof;
preferably from water, acetonitrile, propionitrile, THF, 2-methyl-THF, 1,2-dimethoxyethane, dichloromethane, 1 ,2-dichloroethane, chloroform, toluene, cyclohexane, ethyl acetate, acetic acid, formic acid and mixtures thereof;
more preferably from water, acetonitrile, propionitrile, THF, 2-methyl-THF, 1,2- dimethoxyethane, dichloromethane, 1 ,2-dichloroethane, toluene, ethyl acetate and mixtures thereof;
even more preferably from acetonitrile, THF, 2-methyl-THF, dichloromethane, toluene, ethyl acetate and mixtures thereof.
The catalyst (N) can be used in a pure form or as hydrate.
The catalyst (N) can be used as a solution in solvent (N).
Preferably, the molar ratio between catalyst (N) and compound of formula (XXII) is from 1 : 1000 to 10: 1, more preferably from 1 : 100 to 5 : 1 , even more preferably from 1 :20 to 1 : 1, especially from 1 : 10 to 1 :2.
Preferably, the reaction temperature of reaction (N) is from -20 to 200 °C, more preferably from 0 to 150 °C, even more preferably from 10 to 100 °C.
The reaction (N) can be done in a system, that is closed or open to the atmosphere.
In a closed system, the pressure depends mainly on the boiling point of a solvent (N) and on the reaction temperature of reaction (N). Preferably, the reaction (N) is done at a pressure of from 0.01 bar to 20 bar, more preferably of from 0.1 to 10 bar, even more preferably of from atmospheric pressure to 5 bar.
More preferably, the reaction (N) is done in an open system. Preferably, the reaction time of reaction (N) is from 30 min to 72 h, more preferably from 1 h to 48 h, even more preferably from 2 h to 24 h.
Alternatively, reaction (N) can be done as a continuous gas-phase reaction by passing the evaporated compound of formula (XXII) over the catalyst (N). This gas-phase reaction can be done in the presence of an inert gas, the inert gas is preferably selected from the group consisting of nitrogen, a noble gas and carbon dioxide.
After reaction (N), compound of formula (XXI) can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, filtration, crystallization, distillation, chromatography and any combination thereof, which are known per se to the person skilled in the art.
Preferably, any volatile components of the reaction mixture or added or generated during work up can be removed by evaporation under reduced pressure.
Preferably, the reaction mixture resulting from reaction (N) or any aqueous phase during the work up after reaction (N) can be extracted with a solvent (M-extract),
solvent (M-extract) is preferably selected from the group consisting of water, toluene, benzene, xylene, chlorobenzene, dichloromethane, chloroform, acetic acid Ci_8 alkyl ester and combinations thereof;
the acetic acid Ci_8 alkyl ester is preferably an acetic acid Ci_4 alkyl ester, more preferably selected from the group consisting of ethyl acetate, isopropyl acetate and butyl acetate;
preferably solvent (M-extract) is selected from the group consisting of toluene,
dichloromethane, ethyl acetate, isopropyl acetate and mixtures thereof.
Preferably, any washing of any organic phase after reaction (N) can be done with water, with a base (M-basify), with an aqueous solution of a base (M-basify), with an aqueous solution of an acid (M-acid) or with brine. Preferably base (M-basify) is selected from the group consisting of NaHC03, Na2C03, NaOH and mixtures thereof.
Preferably, base (M-basify) is added in such an amount, that the pH of the resulting mixture is from 7 to 12, more preferably from 8 to 10, even more preferably from 8 to 9.
Preferably, acid (M-acid) is selected from the group consisting of oxalic acid, citric acid, maleic acid, fumaric acid, tartaric acid, NH4C1, HC1, HBr, H2S04, H3P04 and mixtures thereof.
Any extraction or washing can be followed by filtration and concentration of the extract or of the washed mixture .
In another preferred embodiment, compound of formula (XXI) is purified after reaction (N) by chromatography. Any organic phase can be dried, preferably over MgS04 or Na2S04.
Any concentration is preferably done by distillation, preferably under reduced pressure.
Compound of formula (XXI) can be obtained in step (N) as the aldehyde as depicted in formula (XXI), but also in form of its hydrate or hemiacetal. The hemiacetal of compound of formula (XXI), which can result as product from step (N), can be the product of an addition reaction between the aldehyde as depicted in formula (XXI) and an alcohol selected from the group consisting of tert-butanol and isopropanol, or between the aldehyde as depicted in formula (XXI) and any alcohol which is used during the isolation after reaction (N).
Therefore formula (XXI) for the purpose of this invention encompasses the aldehyde, hydrate and the hemiacetal.
When compound of formula (XXI) is obtained from reaction (N) in form of its hydrate or of a hemiacetal, the hydrate or the hemiacetal can be converted into the aldehyde by standard reactions known to the person skilled in the art.
Preferably, compound of formula (XXII) is prepared in a step (O) or in two steps, the two steps are step (01) and step (02); step (O) comprises a reaction (O);
reaction (O) is a reaction of compound of formula (XXIII), with a reagent (O);
(XXIII)
Figure imgf000008_0001
gent (O) is selected from the group consisting of peracetic acid, trifluoroperacetic acid, perbenzoic acid, 3-chloroperbenzoic acid, monoperphthalic acid, dimethyldioxirane, tert- butylhydroperoxide, dibenzoyl peroxide, cumenehydroperoxide, oxygen, air, sodium hypochlorite, oxone, KHSO5, Na202, aqueous H202, H202 dissolved in acetic acid, H202 dissolved in trifluoroacetic acid, and mixtures thereof; step (01) comprises a reaction (01);
reaction (01) is a reaction of compound of formula (XXIII) with water and with a compound
(01);
compound (01) is selected from the group consisting of bromine, N-bromosuccinimide, chlorine, N-chlorosuccinimide, iodine, N-iodosuccinimide, IBr, BrCl, and mixtures thereof; step (02) comprises a reaction (02);
reaction (02) is a reaction of the reaction product from reaction (01) with a base (02);
base (02) is selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide and mixture thereof.
Preferably, reagent (O) is selected from the group consisting of peracetic acid, tert- butylhydroperoxide, oxygen, air, sodium hypochlorite, aqueous H202, H202 dissolved acetic acid, H202 dissolved in trifluoroacetic acid, and mixtures thereof;
more preferably, reagent (O) is aqueous H202.
Preferably, reaction (O) is done in a solvent (O);
solvent (O) is selected from the group consisting of water, aqueous solutions of NaHC03, Na2C03, (NH4)HC03, (NH4)2C03, KHC03 or K2C03, benzene, toluene, NMP, dioxane, acetone, ethyl acetate, methylethylketone, tert-butanol, acetonitrile, chloroform, dichloromethane and mixtures thereof;
preferably from water, aqueous solutions of NaHC03, Na2C03, KHC03 or K2C03, toluene, dioxane, acetone, ethyl acetate, methylethylketone, tert-butanol, acetonitrile,
dichloromethane and mixtures thereof.
Reaction (O) can be done in the presence of a catalyst (O);
catalyst (O) is selected from the group consisting of trifluoroacetic acid, trifluoroacetone, Mn(salen) complex, aldehydes, N-methylmorpholine N-oxide, 2,2,6, 6-tetramethylpiperidine 1-oxyl and mixtures thereof;
aldehydes are preferably isobutyraldehyde or benzaldehyde. Reaction (O) can be done in the presence of a buffer (O);
preferably, buffer (O) is an aqueous buffer and is selected from the group consisting of K2C03 / EDTA-Na2 buffer, phosphate buffer and other buffers known by the skilled person;
more preferably, buffer (O) is an K2C03 / EDTA-Na2 buffer.
Preferably, the reaction temperature of reaction (O) is from -20 to 100 °C, more preferably from -10 to 80 °C, even more preferably from 0 to 50 °C.
The reaction (O) can be done in a system, that is closed or open to the atmosphere.
In a closed system, the pressure depends on the boiling point of a solvent (O) and on the
reaction temperature of reaction (O).
Preferably, the reaction (N) is done at a pressure of from 0.01 bar to 20 bar, more preferably of from 0.1 to 10 bar, even more preferably of from atmospheric pressure to 5 bar.
More preferably the reaction (O) is done in an open system.
Preferably, the reaction time of reaction (O) is from 30 min to 72 h, more preferably from 1 h to 48 h, even more preferably from 2 h to 24 h.
After the reaction (O), the compound of formula (XXII) can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, crystallization, distillation, chromatography and any combination thereof. Preferably, reaction (01) and reaction (02) are conducted in solvent (O), with solvent (O) as defined above, also with all its preferred embodiments.
Preferably, the reaction temperatures of reaction (01) and of reaction (02) are identical or different and independently from each other from -20 to 100 °C, more preferably from -10 to 80 °C, even more preferably from 0 to 50 °C.
Reaction (01) and reaction (02) can independently from each other be done in systems, that are closed or open to the atmosphere.
In a closed system, the pressure depends on the boiling point of a solvent (O) and on the reaction temperature of reaction (01) and reaction (O) respectively.
Preferably, reaction (01) and reaction (02) are independently from each other done at pressures of from 0.01 bar to 20 bar, more preferably of from 0.1 to 10 bar, even more preferably of from atmospheric pressure to 5 bar.
More preferably, reaction (01) and reaction (02) are done in a open system.
Preferably, the reaction times of reaction (01) and of reaction (02) are independently from each other from 30 min to 72 h, more preferably from 1 h to 48 h, even more preferably from 2 h to 24 h.
The reaction product of reaction (01) and the compound of formula (XXII) from reaction (02) can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, filtration, crystallization, distillation,
chromatography and any combination thereof.
Reaction (01) and reaction (02) can be done consecutively without isolation of the reaction product of reaction (01), they can be done in one pot.
Preferably, compound of formula (XXII) is not isolated, step (N) is done directly after step (O) or step (02) respectively in one pot. For this, catalyst (N) is simply added to the reaction mixture resulting from reaction (O) or from reaction (02) respectively.
Preferably, compound of formula (XXIII) is prepared in a step (P);
step (P) comprises a reaction (P); in reaction (P) the compound of formula (XXIV) is exposed to a temperature (P);
Figure imgf000011_0001
temperature (P) is from 0 to 300 °C.
Preferably, temperature (P) is from 5 to 200 °C, more preferably from 100 to 150 °C.
Reaction (P) can be done in a solvent (P);
solvent (P) is selected from the group consisting of benzene, toluene, xylene, hexane, heptane, 1 ,2-dichloroethane, NMP, dichloromethane, chloroform and mixtures thereof;
preferably from benzene, toluene, xylene, dichloromethane and mixtures thereof.
Preferably, reaction (P) is done in the presence of a catalyst (P);
catalyst (P) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid,
camphorsulfonic acid, HC1, HBr, H2S04, KOH, NaOH, KHS04, HN03, H3P04, HC104, BC13, BBr3, BF3OEt2, BF3SMe2, BF3THF, MgCl2, MgBr2, Mgl2, A1C13, Al(0-alkyl)3, 12, A1203, SnCl4, TiCl4, Ti(0-alkyl)4, ZrCl4, Bi203, BiCl3, ZnCl2, PbCl2, FeCl3, Yb(OTf)3, Yb(Cl)3, GaCl3, AlBr3, Ce(OTf)3, LiCl, acidic insoluble inorganic solid, acidic ion exchange resins, carbon treated with an inorganic acid, and mixtures thereof;
preferably from methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, H2S04, KHS04, H3P04, acidic insoluble inorganic solid, acidic ion exchange resins, carbon treated with an inorganic acid, and mixtures thereof.
Preferably, the Al(0-alkyl)3 and the Ti(0-alkyl)4 in the list of possible compounds for catalyst (P) are Al(0-Ci_4 alkyl)3 and Ti(0-Ci_4 alkyl)4.
Preferably, the acidic insoluble inorganic solid is acidic aluminosilicates or silica gel. Preferably, the inorganic acid, with which the carbon was treated, is selected from the group consisting of HC1, H2S04 and HN03. Preferably, the acidic ion exchange resin is selected from the group consisting of copolymers of styrene and divinylbenzene and of perfluorinated branched or linear polyethylenes, these polymers being functionalized with SO3H groups;
more preferably, the acidic ion exchange resin is selected from the group consisting of
copolymers of styrene and divinylbenzene containing more than 5% of divinylbenzene, preferably being macroreticular, and of perfluorinated polyethylenes, these polymers being functionalized with SO3H groups.
When reaction (P) is done in the presence of a catalyst (P), temperature (P) is preferably from 0 to 200 °C, more preferably from 10 to 150 °C, even more preferably from 10 to 100 °C.
Reaction (P) can be done in gas phase by passing evaporated compound of formula (XXIV) through a heated tube, the heated tube can be charged with a catalyst (P).
After reaction (P), the compound of formula (XXIII) can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, crystallization, distillation, chromatography and any combination thereof.
Preferably, compound of formula (XXIV) is prepared in three steps, the three steps are a step (Ql), a step (Q2) and a step (Q3); step (Ql) comprises a reaction (Ql) by a reaction of compound of formula (XXV) with a reagent (Ql);
Figure imgf000012_0001
Q is Br, CI, or I; reagent (Q 1 ) is selected from the group consisting of lithium, magnesium, aluminum, zinc, calcium, isopropylmagnesium chloride, isopropylmagnesium bromide, butyllithium, sec- butyllithium and mixtures thereof; step (Q2) comprises a reaction (Q2);
reaction (Q2) is a reaction of the reaction product of reaction (Ql) with acetone; in step (Q3) comprises a reaction (Q3);
reaction (Q3) is a reaction of the reaction product of reaction (Q2) with a reagent (Q3); reagent (Q3) is selected from the group consisting of water, methanol, ethanol, oxalic acid, citric acid, NH4C1, HCl, HBr, HN03, H2S04, H3P04, acetic acid, propionic acid, formic acid and mixtures thereof. Preferably, Q is Br.
Preferably, reagent (Ql) is selected from the group consisting of lithium, magnesium, aluminum, isopropylmagnesium chloride, isopropylmagnesium bromide and mixtures thereof. Reaction (Ql) can be catalyzed with a catalyst (Ql).
Catalyst (Ql) is selected from the group consisting of iodine, 1 ,2-dibromoethane, TiCl4, A1C13, PbCl2, BiCl3, LiCl and mixtures thereof.
Preferably, reagent (Q3) is water or aqueous NH4C1.
Preferably, reaction (Ql) is performed in a solvent (Ql).
Preferably, reaction (Q2) is performed in a solvent (Q2).
Preferably, reaction (Q3) is performed in a solvent (Q3). Preferably, solvent (Ql), solvent (Q2) and solvent (Q3) are identical or different and
independently from each other selected from THF, methyl-THF, NMP, diethylether, methyl-tert-butylether, methoxycyclopentane, diisopropylether, 1,2-dimethoxyethane, tri Ci_4 alkyl amine and mixtures thereof; more preferably from THF, 2-methyl-THF, 1,2-dimethoxyethane, methyl-tert-butylether, methoxycyclopentane, tri Ci_4 alkyl amine and mixtures thereof;
even more preferably from the group consisting of THF, 2-methyl-THF, 1,2- dimethoxyethane, triethylamine, and mixtures thereof.
Preferably the solvent (Ql), solvent (Q2) and solvent (Q3) are identical.
The reaction temperatures of reaction (Ql), of reaction (Q2) and of reaction (Q3) are identical or different and idependently from each other preferably from -100 to 150 °C, more preferably from -60 to 100 °C, and even more preferably from -20 to 80 °C.
Reaction (Ql), reaction (Q2) and reaction (Q3) can be done at a constant temperature, or the temperature may be modified during the progress of the reactions. For instance, the reactions can run for a certain time at first temperature, and then for a subsequent time at a second temperature different from the first temperature. Alternatively, the temperature may be modified continuously during the reaction.
The reaction times of reaction (Ql), of reaction (Q2) and of reaction (Q3) are identical or different and idependently from each other preferably from 30 min to 48 h, more preferably from 1 to 24 h, even more preferably from 2 to 12 h.
The amounts of solvent (Ql), of solvent (Q2) and of solvent (Q3) are are identical or different and idependently from each other preferably from 2 to 40 fold, more preferably from 3 to 10 fold, even more preferably from 5 to 7 fold, of the weight of compound of formula (XXV), of the weight of the reaction product of reaction (Ql) and of the weight of the reaction product of reaction (Q2) respectively.
Preferably, from 1.0 to 10 mol equivalents, more preferably from 1.1 to 5 mol equivalents, even more preferably from 1.1 to 3 mol equivalents of reagent (Ql) are used, the mol equivalents being based on the mol of compound of formula (XXV).
Preferably, from 1.0 to 10 mol equivalents, more preferably from 1.1 to 5 mol equivalents, even more preferably from 1.1 to 3 mol equivalents of acetone are used, the mol equivalents being based on the mol of compound of formula (XXV). Preferably, from 1.0 to 100 mol equivalents, more preferably from 1.1 to 50 mol equivalents, even more preferably from 1.1 to 30 mol equivalents of reagent (Q3) are used, the mol equivalents being based on the mol of compound of formula (XXV) or of the mol of the reaction product of reaction (Q2).
Preferably, reaction (Ql), reaction (Q2) and reaction (Q3) are done at atmospheric pressure.
Preferably, reaction (Ql), reaction (Q2) and reaction (Q3) are done under inert atmosphere. Preferably, the inert atmosphere is achieved by the use if an inert gas selected from the group consisting of argon, another noble gas, lower boiling alkane, nitrogen and mixtures thereof. The lower boiling alkane is preferably a Ci_3 alkane, i.e. methane, ethane or propane.
After reaction (Ql), reaction (Q2) and reaction (Q3), the reaction product of reaction (Ql), the reaction product of reaction (Q2) and compound of formula (XXIV) respectively can be isolated by standard methods such as evaporation of volatile components, extraction, washing, drying, concentration, crystallization, distillation, chromatography and any combination thereof. Preferably, the reaction product of reaction (Ql) and the reaction product of reaction (Q2) are not isolated.
Preferably, reaction (Ql), reaction (Q2) and reaction (Q3) are done consecutively; preferably, reaction (Ql), reaction (Q2) and reaction (Q3) are done in one pot.
In another preferred embodiment, reaction (Ql) and reaction (Q2) can be done in one pot by adding reagent (Ql) to a mixture of compound of formula (XXV) and acetone in a solvent (Ql); reaction (Q3) is done thereafter, preferably in the same pot. Compound of formula (XXIV) is preferably isolated using conventional methods, such as evaporation of volatile components, hydrolysis and optional acidification of the higher- boiling residue, extraction, and distillation. Any aqueous phase can be extracted, preferably the extraction is done with a solvent (Q- extract). Solvent (Q-extract) is benzene, toluene, ethyl acetate, or isopropyl acetate.
Any organic phase can be dried, preferably with magnesium sulphate.
Any concentration is preferably done by distillation, preferably under reduced pressure.
The compound of formula (XXIV) can be purified, preferably by crystallization or distillation under reduced pressure.
Compounds of formula (XXI) and (XXII) are chiral compounds, and the formulae comprise any enantiomer as well as any mixture of enantiomers of the compounds of formula (XXI), or of formula (XXII) respectively. Compounds of formula (XXV) are known compounds and can be prepared according to known methods.
The progress of any of the reactions (N), (O), (01), (02), (P), (Ql), (Q2) and (Q3) can be monitored by standard techniques, such as nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), High performance Liquid Chromatography (HPLC), Liquid
Chromatography Mass Spectrometry (LCMS), or Thin Layer Chromatography (TLC), and work-up of the reaction mixture can start, when the conversion of the starting material exceeds 95%, or when no more starting material can be detected. The time required for this to occur will depend on the precise reaction temperature and the precise concentrations of all reagents, and may vary from batch to batch.
In general, any organic phase can be dried, preferably over MgS04 or Na2S04, if not stated otherwise. Further subject of the invention is compound of formula (XXI), hydrate of compound of formula (XXI) and hemiacetal of compound of formula (XXI), the hemiacetal of compound of formula (XXI) being a product of an addition reaction between compound of formula (XXI) and an alcohol selected from the group consisting of tert-butanol and isopropanol. Preferably, subject of the invention is compound of formula (XXI).
Further subject of the invention is the use of compound of formula (XXI) as a fragrance, preferably in perfumes or house hold products.
Further subject of the invention is the use of compound of formula (XXI) for the preparation of medetomidine.
Medetomidine is compound of formula (XX)
Figure imgf000017_0001
and is an alpha2 adrenergic agonist, which is currently being used as veterinary sedative and analgesic and is evaluated as anesthetic.
WO201 1/070069A discloses a process for the preparation of medetomidine, in which the imidazole ring is built up during a multi-step process starting from commercially affordable 2,3-dimethyl benzoic acid.
Compound of formula (XX) is preferably prepared from compound of formula (XXI) by a method, that comprises a reaction (Ml);
reaction (Ml) is a reaction between a compound of formula (XXI), an isocyanide and a compound acting as nitrogen source;
the isocyanide is preferably a reagent (M), reagent (M) is selected from the group consisting of p-toluenesulfonylmethyl isocyanide, trifluoromethanesulfonylmethyl isocyanide, methanesulfonylmethyl isocyanide, benzenesulfonylmethyl isocyanide, 4- acetamidobenzenesulfonylmethyl isocyanide and mixtures thereof;
the compound acting as a nitrogen source is preferably a reagent (M-A), reagent (M-A) is selected from the group consisting of ammonia, sulfamic acid, p-toluenesulfonamide, benzenesulfonamide, 4-acetamidobenzenesulfonamide, tritylamine, formamide, urea, urotropine, ethyl carbamate, acetamide and mixtures thereof;
preferably the reaction (Ml) is done in a solvent (M), preferably solvent (M) is selected from the group consisting of Ν,Ν-dimethylformamide, Ci_6 alkanol, formamide, 1 ,2- dimethoxyethane, NMP, toluene, acetonitrile, propionitrile, ethyl carbamate, N,N- dimethylacetamide, water, acetamide and mixtures thereof.
Any sequence of the reaction of reagent (M) and of reagent (M-A) with the compound of formula (XXI) in reaction (Ml) can be used:
compound of formula (XXI) can first be reacted with reagent (M) and then reagent (M-A) added;
or
compound of formula (XXI) can first be first reacted with reagent (M-A) and then reagent (M) added;
or
compound of formula (XXI) can simultaneously be reacted with reagent (M) and with reagent (M-A), this embodiment is preferably suited for the case that reagent (M-A) and solvent (M) are identical and are formamide, ethyl carbamate or acetamide; preferably formamide.
Further subject of the invention is the use of compound of formula (XXII) for the preparation of compound of formula (XXI).
Further subject of the invention is the use of compound of formula (XXIII) for the preparation of compound of formula (XXII).
Further subject of the invention is the use of compound of formula (XXIV) for the preparation of compound of formula (XXIII).
Further subject of the invention is the use of compound of formula (XXV) for the preparation of compound of formula (XXIV). Compared to prior art, the method of the present invention offers several advantages:
Importantly, the whole carbon framework of compound of formula (XXI) is built in few chemical steps, using cheap reagents only. No protecting groups are needed and the overall amount of material used is therefore reduced, the batch size based on molar amounts is increased.
In particular no trityl or acetal protection groups are used and no protection of the imidazoles is necessary. Thereby the number and amount of reagents needed is reduced, and no protecting or deprotecting steps being needed the waste is reduced, contrary to when for example a trityl or acetal protecting group is used. The method has good yields. Compound of formula (XXI) can be easily purified and obtained in a form of high odorous of fragrance purity or high fragrance purity. This is particularly important for products destined for use as fragrance.
The product is distinguished by a very special fragrance sought after in the fragrance industry.
Examples
Methods
1H and 13C NMR spectra were recorded on a Varian VNMRS 500 (500 MHz for 1H and 125 MHz for 13C) instruments in CDC13. Chemical shifts are expressed in parts per million referred to TMS and coupling constants (J) in hertz.
EI means Electron ionization mass spectra (70 eV), they were obtained on an AMD-604 spectrometer.
ESI means Electron spray ionization mass spectra
THF was distilled from sodium/benzophenone ketyl prior to use; the obtained anhydrous THF is called "dry THF" in the following text. Example 1: 2-(2,3-Dimethylphenyl)propan-2-ol, compound of formula (XXIV), prepared via an organomagnesium intermediate
l-Bromo-2,3-dimethylbenzene (compound of formula (XXV), wherein Q is Br; 8.43 g, 45.6 mmol) was dissolved in dry THF (15 mL) and placed in dropping funnel. Separately, Mg wire (1.10 g, 45.3 mmol) in dry THF (5 mL) was placed in a flask equipped with the above mentioned dropping funnel, a stirrer, and a reflux condenser. The l-bromo-2,3- dimethylbenzene solution (1.0 mL) was added via a dropping funnel and the reaction was initiated by the addition of 1 ,2-dibromoethane (3 drops), and then the rest of the l-bromo-2,3- dimethylbenzene solution was added. The content of the dropping funnel was added at such a rate to maintain slight reflux. After completion of the addition, the mixture was refluxed for 1 h and then cooled to 0 °C. A solution of dry acetone (4.2 mL, 58 mmol) in dry THF (15 mL) was added dropwise and the mixture was stirred at a temperature between 0 and 20 °C for 3 h. The mixture was poured into saturated NH4C1 aqueous solution (100 mL) extracted with hexane (5 times with 50 mL each), dried with Na2S04 and evaporated under reduced pressure. The main product was isolated via silica gel column chromatography with hexane: ethyl acetate as eluent (v/v 15: 1 to 10: 1 gradient), to yield 3.50 g (47%) of the title compound.
1H NMR: 1.68 (s, 6H), 1.70 (s, 1H), 2.29 (s, 3H), 2.50 (s, 3H), 7.03 to 7.10 (m, 2H), 7.29 to 7.32 (m, 1H).
13C NMR: 17.72, 21.08, 31.24 , 73.71, 123.11, 125.02, 129.02, 135.09, 138.69, 145.47.
MS (EI): 164 (12), 149 (35), 146 (100), 131, 116, 105, 91. Example 2: 2-(2,3-Dimethylphenyl)propan-2-ol, compound of formula (XXIV), prepared via an organolithium intermediate
1- Bromo-2,3-dimethylbenzene (compound of formula (XXV), wherein Q is Br; 4.25 g, 23.0 mmol) was dissolved in dry THF (20 mL) in a flask equipped with a thermometer and a stirring bar. The mixture was cooled to -78 °C. n-Butyllithium (1.6 M in hexane, 17.5 mL, 28.0 mmol) was added dropwise via a syringe, keeping the temperature below -70 °C. When the addition was complete, the mixture was maintained at -78 °C and stirred at this temperature for 1 h. A solution of dry acetone (1.85 mL, 25.2 mmol) in dry THF (5 mL) was then added at -78 °C. The mixture was stirred at -78 °C for 30 min, the cooling bath was removed, and the mixture was allowed to reach room temperature. The mixture was poured into saturated aqueous NH4C1 solution (100 mL), extracted with hexane (4 times with 50 mL each), dried over Na2S04, and purified by via silica gel column chromatography using hexane:ethyl acetate as eluent (v/v 32: 1) to give 3.45 g (91%) of the title compound.
The measured NMR spectra were identical to those recorded in example 1.
Example 3: l,2-Dimethyl-3-(2-propenyl)benzene, compound of formula (XXIII)
2- (2,3-Dimethylphenyl)propan-2-ol, compound of formula (XXIV), prepared according to either example 1 or example 2, (1.10 g, 6.70 mmol), was dissolved in benzene (20 mL), and p-toluenesulfonic acid monohydrate (35 mg, 0.18 mmol) was added. The mixture was stirred at room temperature for 3 h. Silica gel (200 mg) was added, and stirring was continued for ca. 16 hours, and then the reaction mixture was refluxed for 30 min. After cooling to room temperature, the mixture was filtered, washed with aqueous K2C03 solution, conventionally dried, and concentrated under reduced pressure, to yield 0.90 g (92%) of the title compound. 1H NMR: 2.02 (m, 3H), 2.21 (s, 3H), 2.28 (s, 3H), 4.82 (m, 1H), 5.17 (m, 1H), 6.97 (m, 1H), 7.05 (m, 2H).
Example 4: 2-(2,3-Dimethylphenyl)methyloxirane, compound of formula (XXII)
A buffer was prepared by dissolving K2C03 (20.7 g) and EDTA-Na2 (11.5 mg) in water (100 mL). l,2-Dimethyl-3-(2-propenyl)benzene, compound of formula (XXIII), prepared according to example 3 (0.90 g, 6.16 mmol), was dissolved in a mixture of dichloromethane and acetonitrile (v/v 1 : 1 , 60 mL), and the buffer prepared as described above (9.3 mL) was added. To the resulting mixture, first 1,1,1-trifluoroacetone (60 μί) and then hydrogen peroxide (30% in water, 6.2 mL, 60.7 mmol) were added and the mixture was stirred at room temperature for 2 h. The reaction mixture was diluted with water (100 mL), the organic phase was separated, and the aqueous phase was extracted with dichloromethane (2 times with 50 mL each). The combined organic phases were dried over Na2S04, concentrated under reduced pressure, and the residue was purified by via silica gel column chromatography using hexane:ethyl acetate as eluent (v/v 32: 1) to give 851 mg (85%) of the title compound.
1H NMR: 1.59 (s, 3H), 2.28 (s, 3H), 2.31 (s, 3H), 2.83 (br d, J = 5.4, 1H), 2.98 (d, J = 5.4 Hz,
1H), 7.08 (m, 2H), 7.21 (m, 1H).
MS (EI): 162, 147, 133, 117 (100). Example 5: 2-(2,3-Dimethylphenyl)propanal, compound of formula (XXI)
2-(2,3-Dimethylphenyl)methyloxirane, compound of formula (XXII), prepared according to example 4 (0.84 g, 5.18 mmol), was dissolved in dry dichloromethane (50 mL) and powdered Cu(BF4)2 hydrate (318 mg) was added at room temperature. After 2 h at room temperature, the mixture was washed with water, dried over Na2S04 and concentrated under reduced pressure to yield 0.84 g (100%) of the title product.
1H NMR: 1.40 (d, J = 7.1 Hz, 3H), 2.25 (s, 3H), 2.32 (s, 3H), 3.89 (qd, J = 7.1, 1.0 Hz, 1H), 6.89 to 6.92 (m, 1H), 7.12 (m, 2H), 9.67 (d, J = 1.0 Hz, 1H).
Example 6: Medetomidine, compound of formula (XX)
2-(2,3-Dimethylphenyl)propanal, compound of formula (XXI), prepared according to example 5 (2.43 g, 15.0 mmol) and p-toluenesulfonylmethyl isocyanide (2.73 g, 14.0 mmol) were mixed with EtOH (30 mL). To the stirred suspension powdered NaCN (73 mg, 1.5 mmol) was added. The mixture was stirred for 1 h at room temperature, and then evaporated under reduced pressure to dryness. The residue was placed in an ampoule and treated with MeOH saturated with NH3 (50 mL). The ampoule was heated to 110 °C in an oil bath for three days.
This experiment was repeated once more (2-(2,3-Dimethylphenyl)propanal: 3.24 g, 20.0 mmol; p-toluenesulfonylmethyl isocyanide: 3.90 g, 20.0 mmol).
Both reaction mixtures were combined, evaporated to dryness, dissolved in dichloromethane (150 mL) and washed with 10%> (w/w) aqueous Na2C03 (200 mL) and then with water (200 mL), conventionally dried, evaporated under reduced pressure and purified by via silica gel column chromatography using dichloromethane : methanol as eluent (v/v 15: 1 to 10: 1 gradient), to yield 3.0 g (44%) of medetomidine as a sticky oil. Medetomidine was crystallized from toluene yclohexane, and then recrystallized from aqueous ethanol. 1H NMR: 1.56 (d, J = 7.2 Hz, 3H), 2.18 (s, 3H), 2.25 (s, 3H), 4.35 (q, J = 7.2 Hz, 1H), 6.66 (s, 1H), 6.93 (dd, J = 6.6, 2.2 Hz, 1H), 6.99 to 7.05 (m, 2H), 7.30 (d, J = 1.1 Hz, 1H), 9.84 (broad s, 1H).
13C NMR: 14.65, 20.72, 20.88, 14.12, 117.61, 124.62, 125.53, 127.91, 134.05, 134.60,
136.76, 141.11, 143.23.
MS (ESI): 201 [M+H]+

Claims

Claims
1. A compound of formula (XXI);
Figure imgf000024_0001
hydrate of compound of formula (XXI) and hemiacetal of compound of formula (XXI), the hemiacetal of compound of formula (XXI) being a product of an addition reaction between compound of formula (XXI) and an alcohol selected from the group consisting of tert-butanol and isopropanol.
2. A method for preparation of compound of formula (XXI), with compound of formula (XXI) as defined in claim 1 ;
the method comprises a step (N);
step (N) comprises a reaction (N);
reaction (N) is a reaction of compound of formula (XXII) with a catalyst (N);
Figure imgf000024_0002
catalyst (N) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, camphorsulfonic acid, HC1, HBr, H2S04, HN03, H3P04, HC104, BC13, BBr3, BF3OEt2, BF3SMe2, BF3THF, MgCl2, MgBr2, Mgl2, A1C13, Al(0-alkyl)3, SnCl4, TiCl4, Ti(0-alkyl)4, ZrCl4, Bi203, BiCl3, ZnCl2, PbCl2, FeCl3, ScCl3, NiCl2, Yb(OTf)3, Yb(Cl)3, GaCl3, AlBr3, Ce(OTf)3, LiCl, Cu(BF4)2, Cu(OTf)2, NiBr2(PPh3)2, NiBr2, NiCl2, Pd(OAc)2, PdCl2, PtCl2, InCl3, acidic inorganic solid substance, acidic ion exchange resin, carbon treated with inorganic acid and mixtures thereof.
3. Method according to claim 2, wherein the catalyst (N) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, p- toluenesulfonic acid, HCl, HBr, H2S04, H3P04, BC13, BF3OEt2, MgCl2, MgBr2, A1C13, ZnCl2, Cu(BF4)2, aluminosilicates, acidic ion exchange resins, carbon treated with HCl, H2S04 or HN03, and mixtures thereof.
4. Method according to claim 2 or 3, wherein reaction (N) is done in a solvent (N);
solvent (N) is selected from the group consisting of water, tert-butanol, isopropanol, acetonitrile, propionitrile, THF, methyl-THF, NMP, dioxane, 1 ,2-dimethoxyethane, dichloromethane, 1 ,2-dichloroethane, chloroform, toluene, benzene, chlorobenzene, hexane, cyclohexane, ethyl acetate, acetic acid, formic acid, trifluoroacetic acid and mixtures thereof.
5. Method according to one or more of claims 2 to 4, wherein compound of formula (XXII) is prepared in a step (O) or in two steps, the two steps are step (01) and step (02);
step (O) comprises a reaction (O);
reaction (O) is a reaction of compound of formula (XXIII), with a reagent (O);
(XXIII)
Figure imgf000025_0001
reagent (O) is selected from the group consisting of peracetic acid, trifluoroperacetic acid, perbenzoic acid, 3-chloroperbenzoic acid, monoperphthalic acid, dimethyldioxirane, tert- butylhydroperoxide, dibenzoyl peroxide, cumenehydroperoxide, oxygen, air, sodium hypochlorite, oxone, KHSO5, Na202, aqueous H202, H202 dissolved in acetic acid, H202 dissolved in trifluoroacetic acid, and mixtures thereof; step (01) comprises a reaction (01);
reaction (01) is a reaction of compound of formula (XXIII) with water and with a compound
(01);
compound (01) is selected from the group consisting of bromine, N-bromosuccinimide, chlorine, N-chlorosuccinimide, iodine, N-iodosuccinimide, IBr, BrCl, and mixtures thereof; step (02) comprises a reaction (02); reaction (02) is a reaction of the reaction product from reaction (01) with a base (02);
base (02) is selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide and mixture thereof.
6. Method according to claim 5, wherein reagent (O) is selected from the group consisting of peracetic acid, tert-butylhydroperoxide, oxygen, air, sodium hypochlorite, aqueous H202, H202 dissolved in acetic acid, H202 dissolved in trifluoroacetic acid, and mixtures thereof.
7. Method according to claim 5 or 6, wherein compound of formula (XXIII) is prepared in a step (P);
step (P) comprises a reaction (P);
in reaction (P) the compound of formula (XXIV) is exposed to a temperature (P);
Figure imgf000026_0001
temperature (P) is from 0 to 300 °C.
8. Method according to claim 7, wherein compound of formula (XXIV) is prepared in three steps, the three steps are a step (Ql), a step (Q2) and a step (Q3); step (Ql) comprises a reaction (Ql) by a reaction of compound of formula (XXV) with a reagent (Ql);
Figure imgf000026_0002
Q is Br, CI, or I; reagent (Ql) is selected from the group consisting of lithium, magnesium, aluminum, zinc, calcium, isopropylmagnesium chloride, isopropylmagnesium bromide, butyllithium, sec- butyllithium and mixtures thereof; step (Q2) comprises a reaction (Q2);
reaction (Q2) is a reaction of the reaction product of reaction (Ql) with acetone; in step (Q3) comprises a reaction (Q3);
reaction (Q3) is a reaction of the reaction product of reaction (Q2) with a reagent (Q3); reagent (Q3) is selected from the group consisting of water, methanol, ethanol, oxalic acid, citric acid, NH4C1, HCl, HBr, HNO3, H2S04, H3PO4, acetic acid, propionic acid, formic acid and mixtures thereof.
9. Use of compound of formula (XXI) as a fragrance, with the compound of formula (XXI) as defined in claim 1.
10. Use of compound of formula (XXI) for the preparation of medetomidine, with the
compound of formula (XXI) as defined in claim 1.
PCT/EP2012/070873 2012-05-08 2012-10-22 2-(2,3-dimethylphenyl)-1-propanal and its use as perfume WO2012172120A2 (en)

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EA201691508A EA029130B1 (en) 2012-05-08 2012-11-15 Use of a compound for preparation of medetomidine
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CN201280072267.0A CN104203893B (en) 2012-05-08 2012-11-15 The preparation method of 2-(2,3-3,5-dimethylphenyl)-1-propionic aldehyde
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JP2015517473A (en) * 2012-05-08 2015-06-22 ロンザ・リミテッド Process for preparing 2- (2,3-dimethylphenyl) -1-propanal
JP2015517474A (en) * 2012-06-28 2015-06-22 ロンザ・リミテッド Process for the preparation of medetomidine using chloroacetone
JP2015517475A (en) * 2012-06-28 2015-06-22 ロンザ・リミテッド Method for preparing 2- (2,3-dimethylphenyl) -1-propanal using chloroacetone
WO2016074118A1 (en) * 2014-11-10 2016-05-19 Givaudan Sa Improvements in or relating to organic compounds
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RU2791397C1 (en) * 2022-03-22 2023-03-07 Общество с ограниченной ответственностью "ВИК-здоровье животных" Method for obtaining medetomidine and derivatives
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US9126914B1 (en) 2012-06-28 2015-09-08 Lonza Ltd. Method for preparation of 2-(2,3-dimethylphenyl)-1-propanal with chloroacetone
US9156793B2 (en) 2012-06-28 2015-10-13 Lonza Ltd. Method for preparation of medetomidine with chloroacetone
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US10053420B2 (en) 2015-01-30 2018-08-21 Cambrex Karlskoga Ab Processes for the preparation of compounds, such as 3-arylbutanals, useful in the synthesis of medetomidine
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WO2022207619A1 (en) * 2021-04-01 2022-10-06 Basf Se 2-(2-(3-methylbut-2-en-1yl)phenyl) propanal and mixtures thereof as aroma ingredient
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