NZ700643B2

NZ700643B2 - Method for preparation of 2-(2,3-dimethylphenyl)-1-propanal with chloroacetone

Info

Publication number: NZ700643B2
Application number: NZ700643A
Authority: NZ
Inventors: Robert Bujok; Stephan Elzner; Anna Kulesza; Krzysztof Wojciechowski; Zbigniew Wrobel; Doerwald Florencio Zaragoza
Original assignee: Lonza Ltd
Priority date: 2012-06-28
Filing date: 2012-11-15
Publication date: 2016-07-01

Abstract

The technical problem of the invention relates to a method for the preparation of 2-(2,3-dimethylphenyl)-1-propanal starting from 1-bromo 2,3-dimethylbenzene and chloroacetone, its use in perfumes and its use for the preparation of medetomidine. The solution to the problem involves a method for the preparation of a compound of formula (XXI); the method comprises two steps, the two steps are a step (Q1) and a step (Q2); step (Q1) comprises a reaction (Q1-reac); reaction (Q1-reac) is a reaction of compound of formula (XXV) with a reagent (Q1-reag) to provide a reaction product of reaction (Q1-reac); R1 is Br, Cl, or I; reagent (Q1-reag) is selected from the group consisting of lithium, magnesium, aluminum, zinc, calcium, propylmagnesium chloride, propylmagnesium bromide, butyllithium and mixtures thereof; step (Q2) comprises a reaction (Q2-reac); reaction (Q2-reac) is a reaction of the reaction product of reaction (Q1-reac) with chloroacetone to provide a reaction product of reaction (Q2-reac); the reaction product of reaction (Q2-reac) is a compound of formula (XXII); which is converted to the compound of formula (XXI). preparation of a compound of formula (XXI); the method comprises two steps, the two steps are a step (Q1) and a step (Q2); step (Q1) comprises a reaction (Q1-reac); reaction (Q1-reac) is a reaction of compound of formula (XXV) with a reagent (Q1-reag) to provide a reaction product of reaction (Q1-reac); R1 is Br, Cl, or I; reagent (Q1-reag) is selected from the group consisting of lithium, magnesium, aluminum, zinc, calcium, propylmagnesium chloride, propylmagnesium bromide, butyllithium and mixtures thereof; step (Q2) comprises a reaction (Q2-reac); reaction (Q2-reac) is a reaction of the reaction product of reaction (Q1-reac) with chloroacetone to provide a reaction product of reaction (Q2-reac); the reaction product of reaction (Q2-reac) is a compound of formula (XXII); which is converted to the compound of formula (XXI).

Description

METHOD FOR PREPARATION OF 2-(2,3-DIMETHYLPHENYL)PROPANAL WITH CHLOROACETONE The invention discloses a method for the preparation of 2-(2,3-dimethylphenyl)propanal starting from 1-bromo 2,3-dimethylbenzene and chloroacetone, 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 us household products. Alpha, beta-unsaturated aromatic aldehydes, such as substituted cinnamic aldehydes, are disclosed to have distinct fragrance and are therefore used in the perfume industry.

WO 37 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 nce.

The perfume and household product ry 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 tent quality.

High purity and strong fragrances are d. The present invention provides a new alpha, nsaturated aromatic de analogue, which has strong and interesting, aldehydic fragrance, intensely spicy and sweet, and an ed process for the production thereof.

Medetomidine is the compound of formula (XX) and is an alpha2 adrenergic agonist, which is currently being used as veterinary sedative and analgesic and is evaluated as anesthetic.

CH CH 3 3 N CH (XX) Medetomidine is a 4-alkylimidazole. 4-Alkylimidazoles without additional substituents at the nitrogen moiety are usually mixtures of two tautomers. For instance, in the case of medetomidine, two tautomeric forms, represented by compound of formula (XX) and compound of formula (XX-T), CH CH 3 3 N CH (XX-T) will usually interconvert if medetomidine is dissolved or in a non-crystalline state. If one of the tautomeric forms prevails or if they are present in equal amounts is dependent on various factors, such as pH, solvent or temperature.

In the text, formula (XX) is used for medetomidine, and is meant to comprise both tautomeric forms as well as their mixture.

US 2010/0048915 A discloses a method for the preparation of medetomidine by reaction of nated imidazoles with 2,3-dimethylbenzaldehyde using Grignard ts.

Cordi et al., Synth. Commun. 1996, 26, 1585-1593, discloses the preparation of medetomidine by reaction of 4-imidazolcarboxaldehyde with 2,3-dimethylphenylmagnesium bromide.

WO 00/42851 A discloses the use of midine for inhibition of marine biofouling on surfaces.

The previously disclosed methods of preparation of compound of formula (XX) often use protecting groups, for example triphenylmethyl (trityl) residues, which entails high material ption and the need for tion/deprotection steps. Consequently, these syntheses are long and expensive. Furthermore rather expensive and non-readily ble starting materials are used.

There was a need for a tic route, which does not need protecting , starts with less expensive substrates, avoids large amounts of waste and has satisfying yields.

In the following text, halogen means F, Cl, Br or I, preferably Cl, Br or I; "alkyl" means linear, branched, cyclic or cyclo alkyl, preferably it means the commonly accepted meaning linear or ed 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, norbomyl, adamantyl, and the like; "cyclic alkyl" or "cyclo alkyl" are intended to e cyclo aliphatic, bicyclo tic and le aliphatic residues; "alkane" means a linear, branched or cyclic alkane, preferably linear or branched alkane; "alkanol" means a hydroxyalkane, with alkane having the meaning as deﬁned above also with its red embodiments; Ac acetyl; tBu tertiary butyl; DBU l,8-diazabicyclo[5 .4.0]undecene; DABCO l,4-diazabicyclo[2.2.2]octane; DMF N,N—dimethylformamide; hexanes mixture of isomeric hexanes; NMP N—methylpyrrolidone; OTf triﬂuoromethanesulfonate, also known as triﬂate; sulfamic acid HO-SOz-NHZ; THF ydroﬁlran; xylene l,2-dimethylbenzene, l,3-dimethylbenzene, l,4-dimethylbenzene or a mixture thereof; if not otherwise stated.

Subject of the ion is a method for preparation of compound of a (XXI); CH3 CH3 0 CH3 H Goa) the method comprises two steps, the two steps are a step (Q1) and a step (Q2); step (Ql) comprises a reaction (Ql-reac); on (Q1-reac) is a reaction of compound of formula (XXV) with a reagent (Q1-reag) to provide a reaction product of reaction (Q1-reac); R1 is Br, Cl, or I; reagent (Q1-reag) is selected from the group consisting of lithium, magnesium, aluminum, zinc, calcium, propylmagnesium chloride, propylmagnesium bromide, butyllithium and mixtures f; step (Q2) comprises a reaction ac); reaction (Q2-reac) is a reaction of the reaction product of reaction (Q1-reac) with chloroacetone to provide a reaction product of reaction (Q2-reac); the reaction product of reaction (Q2-reac) is a compound of formula (XXII); which is converted to nd of formula (XXI).

Preferably, R1 is Br.

Preferably, reagent (Q1-reag) is selected from the group consisting of lithium, magnesium, um, isopropylmagnesium de, isopropylmagnesium bromide, llithium, secbutyllithium , tert-butyllithium, and mixtures thereof; more ably, reagent (Q1-reag) is selected from the group consisting of lithium, magnesium, isopropylmagnesium chloride, pylmagnesium bromide, n-butyllithium and mixtures thereof.

Reaction (Q1-reac) can be done in the presence of a catalyst (Q1-cat); catalyst (Ql-cat) is selected from the group consisting of iodine, l,2-dibromoethane, TiCl4, AlClg, PbClz, BlClg, LiCl and mixtures thereof. ably, reaction (Ql-reac) is performed in a solvent (Ql-solv).

Preferably, reaction (Q2-reac) is performed in a solvent (Q2-solv).

Preferably, solvent (Ql-solv) and solvent (Q2-solv) are identical or ent and independently from each other selected from the group consisting of THF, toluene, heptane, cyclohexane, ethylcyclohexane, hexane, 2-methyl-THF, NMP, diethylether, methyl-tert-butylether, methoxycyclopentane, diisopropylether, 2,2,5,5- tetramethyl-THF, l,2-dimethoxyethane, N,N,N',N'-tetramethyl-l,2-ethylenediamine, 1,4- diazabicyclo[2.2.2]octane, tri C1_4 alkyl amine and mixtures thereof; more ably from the group consisting of THF, toluene, heptane, hexane, yl-THF, l,2-dimethoxyethane, methyl-tert-butylether, methoxycyclopentane, tri C1_4 alkyl amine and mixtures thereof; even more preferably from the group consisting of THF, toluene, heptane, hexane, 2-methyl- THF, l,2-dimethoxyethane, triethylamine and mixtures thereof.

When heptane is used as solvent, it is often used as a mixture of ic heptanes.

In one particular embodiment, solvent (Ql-solv) is THF, hexane or a mixture f, and solvent (Q2-solv) is THF, hexane, toluene or a mixture thereof.

In r particular embodiment, solvent lv) and solvent (Q2-solv) are identical.

The reaction temperatures of reaction (Ql-reac) and of reaction (Q2-reac) are identical or different and ndently from each other preferably from -lOO to 150 CC, more preferably from -90 to 100 oC, and even more preferably from -80 to 80 oC.

Reaction ac) and reaction (Q2-reac) can be done at a constant temperature, or the temperature may be modiﬁed during the progress of the ons. 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-reac) and of reaction (Q2-reac) are identical or ent and independently 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-solv) and of solvent (Q2-solv) are identical or different and independently from each other preferably from 2 to 40 fold, more ably from 3 to 20 fold, even more preferably from 5 to 10 fold, of the weight of compound of formula (XXV) in case of solvent (Ql-solv), and of the weight of the on t of reaction (Ql-reac) in case of t (Q2-solv).

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-reag) are used, the mol equivalents being based on the mol of compound of a (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 chloroacetone are used, the mol equivalents being based on the mol of compound of formula (XXV).

Preferably, reaction (Ql-reac) and reaction (Q2-reac) are done at atmospheric pressure.

Preferably, reaction (Ql-reac) and reaction (Q2-reac) are done under inert atmosphere.

Preferably, the inert atmosphere is achieved by the use if an inert gas preferably selected from the group consisting of argon, another noble gas, lower boiling alkane, nitrogen and mixtures thereof.

The lower boiling alkane is preferably a C1_3 alkane, i.e. methane, ethane or propane.

After reaction ac), compound of formula (XXII) can be isolated by standard methods such as ation of volatile components, extraction, washing, drying, concentration, crystallization, distillation, chromatography and any combination thereof, which are known per se to the person skilled in the art.

Preferably, the reaction product of reaction (Ql-reac) is not isolated.

Preferably, reaction (Ql-reac) and on (Q2-reac) are done consecutively. 2012/072799 ably, reaction (Ql-reac) and reaction (Q2-reac) are done in one pot.

In another preferred embodiment, reaction (Ql-reac) and reaction (Q2-reac) can be done in one pot by adding reagent (Ql-reag) to a mixture of compound of a (XXV) and chloroacetone in a solvent (Ql-solv).

Preferably, for the isolation of compound of formula (XXII) after reaction (Q2-reac), a t (Q3) is combined with the reaction mixture derived from reaction (Q2-reac); reagent (Q3) is selected from the group consisting of water, methanol, ethanol, oxalic acid, citric acid, NH4Cl, HCl, HBr, HNOg, H2804, H3PO4, acetic acid, propionic acid, formic acid and mixtures thereof.

Preferably, reagent (Q3) is water or aqueous NH4Cl; more preferably, t (Q3) is water.

Preferably, from 0.01 to 1000 mol equivalents, more preferably from 0.02 to 1000 mol equivalents, of t (Q3) are used, the mol equivalents being based on the mol of compound of formula (XXV). Reagent (Q3) is used to neutralize any excess of reagent (Q1- reag), therefore the amount of reagent (Q3) is adjusted with respect to the excess of reagent (Q l -reag) used in reaction (Q l -reac).

Compound of formula (XXII) is preferably ed using conventional methods, such as evaporation of le ents, hydrolysis and optional acidification of the higherboiling residue, tion, and distillation.

Any extraction of an aqueous phase is done preferably 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 (XXII) can be purified, preferably by crystallization or distillation under reduced pressure.

Preferably, nd of formula (XXI) is prepared in a step (N); step (N) comprises a reaction (N-reac); step (N) is done after step (Q2); reaction (N-reac) is a reaction of compound of formula (XXII) with a catalyst (N-cat); catalyst (N-cat) is ed from the group consisting of acetic acid, formic acid, triﬂuoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, camphorsulfonic acid, HCl, HBr, H2804, HNOg, H3PO4, HClO4, BClg, BBI‘g, BFgoEtz, BngMez, BFgTHF, MgClz, MgBrz, MgIz, AlClg, 1_4 alkyl)3, SnCl4, TiCl4, Ti(O-C1_4 alkyl)4, ZrCl4, Bleg, BlClg, ZnClz, PbClz, F€C13, SCClg, NiClz, Yb(OTf)3, Yb(Cl)3, GaClg, AlBrg, Ce(OTf)3, LiCl, Cu(BF4)2, Cu(OTf)2, NiBr2(PPh3)2, NiBrz, NiClz, Pd(OAc)2, PdClz, PtClz, InClg, acidic inorganic solid substance, acidic ion ge resin, carbon treated with nic acid and mixtures thereof.

Compound of a (XXII) is preferably prepared by the reaction (Q2-reac).

Preferably, the acidic inorganic solid substance in the list of possible compounds for st (N-cat) is aluminosilicate.

Preferably, the acidic ion exchange resin in the list of possible compounds for catalyst (N-cat) is selected from the group ting of copolymers of styrene and diVinylbenzene and of perﬂuorinated branched or linear polyethylenes, these polymers being functionalized with SOgH 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 lbenzene, preferably being macroreticular, and of perﬂuorinated polyethylenes, these polymers being onalized with SOgH groups.

Preferably, the inorganic acid in the list of possible compounds for catalyst (N-cat), with which the carbon was treated, is selected from the group consisting of HCl, H2804 and HNOg.

Preferably, catalyst (N-cat) is selected from the group consisting of acetic acid, formic acid, roacetic acid, methanesulfonic acid, p-toluenesulfonic acid, HCl, HBr, H2804, H3PO4, BClg, BFgoEtz, MgClz, MgBrz, AlClg, ZnClz, Cu(BF4)2, aluminosilicate, acidic ion exchange resin, carbon treated with HCl, H2804 or nd mixtures f; more preferably, catalyst (N-cat) is selected from the group consisting of acetic acid, formic acid, methanesulfonic acid, p-toluenesulfonic acid, HCl, H2804, BFgoEtz, Cu(BF4)2, osilicate, acidic ion exchange resin, and mixtures thereof; even more preferably catalyst (N-cat) is selected from the group consisting of methanesulfonic acid, p-toluenesulfonic acid, H2804, BFgoEtz, Cu(BF4)2, aluminosilicate, acidic ion exchange resin, and mixtures thereof; especially catalyst (N-cat) is selected from the group consisting of methanesulfonic acid, p- toluenesulfonic acid, H2804, BF30Et2 and mixtures thereof.

Preferably, reaction c) is done in a solvent (N—solv). t (N—solv) is preferably selected from the group consisting of water, tert-butanol, isopropanol, acetonitrile, nitrile, THF, methyl-THF, NMP, dioxane, l,2- dimethoxyethane, dichloromethane, l,2-dichloroethane, chloroform, toluene, benzene, chlorobenzene, hexane, cyclohexane, ethyl acetate, acetic acid, formic acid, triﬂuoroacetic acid and mixtures thereof; more ably from water, acetonitrile, propionitrile, THF, 2-methyl-THF, l,2- dimethoxyethane, dichloromethane, l,2-dichloroethane, form, toluene, cyclohexane, ethyl acetate, acetic acid, formic acid and mixtures f; even more preferably from water, acetonitrile, propionitrile, THF, 2-methyl-THF, l,2- dimethoxyethane, dichloromethane, l,2-dichloroethane, toluene, ethyl e and mixtures thereof; especially from acetonitrile, THF, 2-methyl-THF, dichloromethane, toluene, ethyl acetate and mixtures thereof.

The catalyst (N-cat) can be used in a pure form or as hydrate.

The catalyst (N-cat) can be used as a solution in solvent (N—solv).

Preferably, the molar ratio between catalyst (N-cat) and compound of formula (XXII) is from 1:1000 to 10:1, more preferably from 1:100 to 5:1, even more preferably from 1:50 to 1:1, especially from 1:25 to 1:2.

Preferably, the reaction ature of reaction (N-reac) is from -20 to 200 CC, more preferably from 0 to 150 OC, even more preferably from 10 to 100 oC.

The reaction (N-reac) 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-solv) and on the reaction temperature of reaction (N-reac). ably, the reaction (N-reac) 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-reac) is done in an open system.

Preferably, the reaction time of reaction (N-reac) is from 30 min to 72 h, more preferably from 1 h to 48 h, even more preferably from 1.5 h to 24 h. atively, reaction (N-reac) can be done as a continuous gas-phase reaction by passing the evaporated compound of formula (XXII) over the catalyst (N-cat). This gas-phase reaction can be done in the ce of an inert gas, the inert gas is preferably selected from the group ting of nitrogen, a noble gas and carbon e.

After reaction (N-reac), compound of formula (XXI) can be ed by standard methods such as evaporation of le components, extraction, washing, , concentration, filtration, crystallization, distillation, chromatography and any combination thereof, which are known per se to the person d 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-reac) or any aqueous phase during the work up after reaction (N-reac) 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, form, acetic acid CH; alkyl ester and combinations thereof; the acetic acid CH; alkyl ester is preferably an acetic acid C1_4 alkyl ester, more preferably selected from the group ting of ethyl acetate, isopropyl acetate and butyl acetate; preferably solvent (M-extract) is selected from the group consisting of toluene, dichloromethane, ethyl acetate, pyl acetate and mixtures thereof.

Preferably, any washing of any organic phase after reaction (N-reac) 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 ofNaHCOg, N32C03, 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 ably from 8 to 9.

Preferably, acid (M-acid) is selected from the group consisting of oxalic acid, citric acid, maleic acid, c acid, tartaric acid, NH4Cl, HCl, HBr, H2804, H3PO4 and mixtures thereof.

Any tion 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 on (N- reac) by chromatography.

Any organic phase can be dried, preferably over MgSO4 or NaZSO4.

Any concentration is preferably done by distillation, preferably under reduced pressure. nd 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 etal of nd of formula (XXI), which can result as product from step (N), can be the product of an addition on 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-reac).

Also this hydrate and this hemiacetal can be directly used in step (Ml).

When compound of formula (XXI) is obtained from reaction (N-reac) in form of its hydrate or of a hemiacetal, the hydrate or the hemiacetal can be converted into the aldehyde by standard ons known to the person skilled in the art. nd of formula (XXI) can be used as a fragrance, preferably in es or house hold products.

Compound of formula (XXI) can be also be used for the preparation of medetomidine, which is nd of formula (XX).

Compound of formula (XX) is preferably prepared from compound of formula (XXI) by a method (M); the method (M) comprises a step (Ml); step (Ml) comprises a reaction (Ml-reac); reaction (Ml-reac) is a reaction between a nd of formula (XXI), a reagent (M-reag) and a reagent (M-A) in a t (M-solv); reagent (M-reag) is selected from the group consisting of p-toluenesulfonylmethyl isocyanide, triﬂuoromethanesulfonylmethyl isocyanide, methanesulfonylmethyl isocyanide, benzenesulfonylmethyl isocyanide, 4-acetamidobenzenesulfonylmethyl isocyanide and mixtures thereof; reagent (M-A) is selected from the group consisting of a, sulfamic acid, p- toluenesulfonamide, benzenesulfonamide, 4-acetamidobenzenesulfonamide, tritylamine, formamide, urea, urotropine, ethyl carbamate, acetamide and mixtures solvent (M-solv) is selected from the group consisting dimethylformamide, C1_6 alkanol, formamide, l,2-dimethoxyethane, NMP, toluene, acetonitrile, propionitrile, ethyl carbamate, methylacetamide, water, acetamide and mixtures thereof.

Preferably, reagent (M-reag) is ed from the group consisting of p-toluenesulfonylmethyl isocyanide, benzenesulfonylmethyl isocyanide and mixtures thereof; more preferably, reagent (M-reag) is enesulfonylmethyl isocyanide.

Preferably, reagent (M-A) is selected from the group consisting of ammonia, sulfamic acid, p- toluenesulfonamide, benzenesulfonamide, 4-acetamidobenzenesulfonamide, amine, formamide and mixtures f; more preferably, reagent (M-A) is ed from the group consisting of ammonia, p- toluenesulfonamide, benzenesulfonamide, formamide, 4- acetamidobenzenesulfonamide, tritylamine and mixtures thereof; even more preferably, reagent (M-A) is selected from the group consisting of a, p- toluenesulfonamide, formamide, and mixtures thereof; especially, reagent (M-A) is ammonia or formamide.

Preferably, reaction (Ml-reac) is done in the presence of a compound (M-comp), compound (M-comp) is selected from the group consisting of ammonia, tritylamine, NaCN, KCN, piperidine, DBU, DABCO, ylamine, tributylamine, 4- dimethylaminopyridine, pyridine, tBuOK, tBuONa, NaHCOg, N32C03, (NH4)HC03, (NH4)2C03, KHCOg, K2C03, NaOAc, KOAc, NaOH, KOH, Ca(OH)2, KF and mixtures thereof; preferably, compound (M-comp) is selected from the group consisting of ammonia, tritylamine, NaCN, KCN, piperidine, tBuOK, tBuONa, KOH, K2C03, N32C03, KF and mixtures thereof; more ably, compound (M-comp) is selected from the group consisting of ammonia, NaCN, KCN, piperidine, tBuOK, , K2C03, N32C03, KF and mixtures thereof; even more preferably, compound (M-comp) is selected from the group consisting of ammonia, NaCN, K2C03, tBuOK, tBuONa, N32C03 and mixtures thereof; especially, compound (M-comp) is selected from the group consisting of ammonia, NaCN, tBuOK, tBuONa, K2C03, N32C03 and mixtures thereof; more especially, compound (M-comp) is K2C03, N32C03’N3CN or ammonia; even more especially, compound (M-comp) is N32C03’ NaCN or ammonia. ably, solvent (M-solv) is selected from the group consisting ofN,N— dimethylformamide, methanol, l, n-propanol, isopropanol, butanol, pentanol, hexanol, water, ide, l,2-dimethoxyethane, NMP, toluene, acetonitrile, propionitrile, ethyl carbamate, N,N-dimethylacetamide, acetamide and mixtures more preferably, solvent v) is selected from the group consisting ofN,N— dimethylformamide, ol, ethanol, ethyl carbamate, formamide, acetamide and mixture thereof.

The reagent (M-A) can be used as such or in form of a on in a solvent (M-A). Solvent (M-A) is cal or different from solvent (M-solv), preferably cal, and comprises the same group of solvents as t (M-solv), also with respect to all of the preferred embodiments of solvent (M-solv).

When reagent (M-A) is ammonia, then reagent (M-A) is preferably used in form of a solution, preferably in form of a solution in methanol or ethanol.

In case of ethyl carbamate, formamide and acetamide, reagent (M-A) can be identical with solvent (M-solv) and can be used as solvent (M-solv).

Preferably, the reaction temperature of reaction (Ml-reac) is from -10 to 250 CC, more preferably from 0 to 200 OC, even more preferably from 10 to 180 oC.

The reaction (Ml-reac) can be done in a , that is closed or open to the atmosphere; preferably the reaction (Ml-reac) is done in a closed .

In a closed system, the pressure depends mainly on the boiling point of the solvent (M-solv), on the amount of ammonia used, and on the reaction temperature of reaction (Ml- reac); preferably, the reaction (Ml-reac) is done at a pressure of from heric pressure to 20 bar, more preferably of from atmospheric pressure to 10 bar, even more preferably of from atmospheric pressure to 5 bar.

Preferably, the reaction time of reaction (Ml-reac) is from 30 min to 72 h, more preferably from 30 min to 48 h, even more preferably from 30 min to 24 h.

Reaction (Ml-reac) may be conducted at a constant temperature, or the temperature may be modified during the progress of the reaction. For instance, the reaction may be run for a n time at ﬁrst temperature, and then for a given time at second temperature different from the ﬁrst temperature; alternatively, the temperature may be modiﬁed continuously during the reaction.

Preferably, from 0.5 to 10 mol equivalents, more preferably from 0.5 to 5 mol equivalents, even more preferably from 0.5 to 3 mol equivalents of t (M-reag) are used, the mol equivalents being based on the mol of compound of a (XXI).

When one or more ts (M-A) different from ammonia, formamide and ethyl carbamate are used, the total amount of substances different from ammonia, ide and ethyl carbamate used as reagent (M-A) is 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, the mol equivalents being based on the mol of compound of formula (XXI).

When ammonia, ide, ethyl carbamate or mixtures thereof are used as reagent (M-A), ably 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 ammonia, formamide, ethyl carbamate or mixtures thereof are used, the mol equivalents being based on the mol of nd of formula (XXI).

When one or more substances selected from the group ammonia, formamide and ethyl carbamate, and one or more substances different from ammonia, formamide and ethyl carbamate are used as reagent (M-A), the given amounts for ammonia, formamide and ethyl carbamate, and the given amounts for the one or more nces different from ammonia, formamide and ethyl carbamate, add up to the total amount of reagent (M-A); the total amount of reagent (M-A) is 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, the mol equivalents being based on the mol of nd of formula (XXI).

Preferably from 0.01 to 15 mol equivalents, more preferably from 0.02 to 10 mol equivalents, even more preferably from 0.02 to 5 mol equivalents of compound (M-comp) are used, the mol equivalents being based on the mol of compound of formula (XXI).

When reagent (M-A) is not one or more substances selected from the group ammonia, formamide and ethyl carbamate, then preferably from 1 to 15 mol equivalents, more preferably from 1 to 10 mol lents, even more preferably from 1 to 5 mol equivalents of compound (M-comp) are used, the mol equivalents being based on the mol of compound of formula (XXI).

Preferably, the amount of solvent (M-solV) is from 0.5 to 20 fold, more preferably from 1 to fold, even more preferably of from 2 to 20 fold, of the weight of compound of formula (XXI).

Preferably, the reaction (Ml-reac) is done under inert atmosphere.

When tritylamine is used as reagent (M-A), the product of reaction (Ml-reac) may be N-trityl medetomidine and the trityl residue would have to be removed.

Preferably in this case, the method for preparation of compound of formula (XX) ses a further step (M2); step (M2) is done after step (Ml); step (M2) comprises a reaction (M2- reac); reaction (M2-reac) is the ent of the product of reaction (Ml-reac) with an acid (M-acid detrit). Acid (M-acid detrit) is preferably selected from the group consisting of acetic acid, propionic acid, formic acid, HCl or mixtures thereof.

Acid (M-acid detrit) can be used as an aqueous solution.

Any sequence of the reaction of t (M-reag) and of reagent (M-A) with the compound of formula (XXI) in reaction (Ml-reac) can be used: compound of a (XXI) can first be reacted with t (M-reag) and then reagent (M- A) added; compound of formula (XXI) can first be reacted with reagent (M-A) and then reagent (M- reag) added; or compound of formula (XXI) can simultaneously be reacted with t (M-reag) and with reagent (M-A), this embodiment is preferably suited for the case that reagent (M-A) and solvent (M-solV) are identical and are formamide, ethyl ate or acetamide; ably formamide. ably, compound of formula (XXI) is ﬁrst reacted with reagent (M-reag) and then reagent (M-A) added; compound of formula (XXI) is simultaneously d with reagent (M-reag) and with reagent (M-A).

Step (Ml) can therefore be done in three alternatives, the three alternatives are alternative (M l -A l ), alternative (M 1 -A2) and alternative (M 1 -A3).

Alternative (Ml-Al) comprises two consecutive steps, a ﬁrst step (Ml-Al-l) and a second step (M 1 -Al -2); step (Ml-Al-l) comprises a reaction (Ml-Al-l); reaction (Ml-Al-l) is a reaction of compound of formula (XXI) with reagent (M-reag) in the ce of compound (M-comp) in solvent (M-solv); step (Ml-Al-2) comprises a reaction (Ml-Al-2); reaction (Ml-Al-2) is a reaction of the reaction product of reaction (Ml-Al-l) with reagent (M-A) in solvent (M-solv).

Preferably, the reaction temperature of reaction (Ml-Al-l) is from -10 to 250 CC, more preferably from 0 to 200 OC, even more ably from 10 to 180 oC.

Preferably, the reaction temperature of on (Ml-Al-2) is from 20 to 250 CC, more preferably from 50 to 200 oC, even more preferably from 80 to 180 oC.

Preferably from 0.01 to 1 mol equivalents, more ably from 0.02 to 1 mol equivalents, even more preferably from 0.02 to 1 mol equivalents of compound (M-comp) are used in reaction (Ml-Al-l), the mol equivalents being based on the mol of compound of formula (XXI).

Reaction (Ml-Al-Z) can be done in the presence of compound p).

When t (M-A) is not one or more substances selected from the group ammonia, formamide and ethyl carbamate, then reaction (Ml-Al-2) is preferably done in the presence of compound (M-comp); preferably from 1 to 15 mol equivalents, more preferably from 1 to 10 mol equivalents, even more preferably from 1 to 5 mol equivalents of nd (M-comp) are used, the mol equivalents being based on the mol of nd of formula (XXI).

After reaction (M 1 -Al -l), the reaction product of reaction (Ml-Al -1) can be isolated by standard methods such as hydrolysis, ﬁltration, evaporation of the volatile components, extraction, g, drying, concentration, crystallization, lation, tography and any combination thereof, which are known per se to the person skilled in the art.

The reaction product of reaction (Ml-Al-l) is the compound of formula (XXIII); CH3 CH3 6 CH3 XXIII I? ( ) N S\ I \0 wherein R2 is 4-tolyl, phenyl, 4-acetamidophenyl, methyl or triﬂuoromethyl; preferably, R2 is 4-tolyl, which is compound of formula (23).

CH3 CH3 <3 CH3 I? (23) N S\O\ Compound of formula (XXIII) can be isolated after on (Ml-Al-l) by addition of water to the reaction mixture as obtained from reaction (Ml-Al-l). The addition of water precipitates compound of formula (XXIII). Compound of a (XXIII) can then be isolated by ﬁltration, followed preferably by washing and drying. Compound of formula (XXIII) can be ﬁarther purified by crystallization.

The volume of water used for this precipitation is preferably from 0.01 to 5 fold, more preferably from 0.05 to 2 fold, of the volume of solvent (M-solv).

Alternative ) comprises two consecutive steps, a ﬁrst step (Ml-A2-l) and a second step (Ml-A2-2); step (Ml-A2-l) comprises a reaction (Ml-A2-l); reaction (Ml-A2-l) is a reaction of nd of formula (XXI) with reagent (M-A) in solvent (M-solv); step (Ml-A2-2) comprises a on (Ml-A2-2). reaction (Ml-A2-2) is a on of the reaction product of reaction (Ml-A2-l) with reagent (M-reag) in the presence of compound (M-comp) in solvent (M-solv).

Preferably, the reaction temperature of reaction (Ml-A2-l) is from 0 to 250 CC, more preferably from 10 to 200 OC, even more preferably from 20 to 180 oC. ably, the reaction temperature of reaction (Ml-A2-2) is from -10 to 250 CC, more preferably from 0 to 200 OC, even more preferably from 20 to 180 0C.

In case of reagent (M-A) not being ammonia and tritylamine, reaction (Ml-A2-l) can be done in the presence of an acid (Ml-A2-l); acid (Ml-A2-l) is selected from the group consisting of p-toluenesulfonic acid, methanesulfonic acid and benzenesulfonic acid; preferably from 0.01 to 1 mol equivalents, more preferably from 0.05 to 0.5 mol equivalents, even more ably from 0.1 to 0.3 mol equivalents of acid (Ml-A2-l) are used in reaction (Ml-A2-l), the mol lents being based on the mol of compound of formula (XXI).

Reaction -l) can be done in the presence of compound (M-comp).

When reagent (M-A) is not one or more substances ed from the group ammonia, formamide and ethyl carbamate, then reaction (Ml-A2-l) is preferably done in the ce of compound (M-comp); preferably from 1 to 15 mol lents, more preferably from 1 to 10 mol equivalents, even more preferably from 1 to 5 mol equivalents of compound p) are used, the mol equivalents being based on the mol of compound of formula (XXI).

Preferably from 0.01 to 1 mol equivalents, more preferably from 0.02 to 1 mol equivalents, even more preferably from 0.02 to 1 mol equivalents of compound (M-comp) are used in reaction (Ml-A2-2), the mol equivalents being based on the mol of compound of formula (XXI).

Alternative (Ml -A3) comprises a step (Ml -A3 - 1) step (Ml -A3 - 1) comprises a reaction (Ml -A3 - l ); reaction (Ml-A3-l) is a reaction of compound of formula (XXI) with reagent (M-reag) and with with reagent (M-A) in solvent (M-solv).

Preferably, the on temperature of on (Ml-A3-l) is from 0 to 250 CC, more preferably from 20 to 200 OC, even more preferably from 50 to 180 oC.

Reaction -l) can be done in the presence of compound (M-comp); preferably from 1 to 15 mol equivalents, more preferably from 1 to 10 mol equivalents, even more preferably from 1 to 5 mol equivalents of compound (M-comp) are used in reaction (Ml- A3-l), the mol equivalents being based on the mol of compound of formula (XXI).

In case of all these three alternatives, t (M-reag), reagent (M-A), nd (M-comp) and solvent (M-solv) are as defined herein, also with all their preferred embodiments.

When the reaction (Ml-reac) is completed, the compound of formula (XX) can be isolated by standard methods such as evaporation of volatile components, extraction, washing, , tration, filtration, crystallization, distillation, chromatography and any combination thereof, which are known per se to the person skilled in the art.

Preferably, the volatile components of the on mixture are removed by evaporation under reduced pressure.

Preferably, the reaction mixture resulting from on (Ml-reac) or the reaction mixture resulting from reaction ac) can be extracted with a solvent (M-extract), with solvent ract) as defined above, also with all its preferred embodiments.

The extraction can be followed by filtration and concentration of the extract.

Preferably, after an extraction with a t (M-extract), the t resulting from the extraction with solvent (M-extract) can be extracted with an aqueous solution of an acid (M- acid), with acid (M-acid) as defined above, also with all its preferred embodiments.

The extract resulting from the extraction with an aqueous solution of acid (M-acid) can be washed with a t (M-wash).

Preferably, solvent (M-wash) is selected from the group consisting of toluene, benzene, xylene, chlorobenzene, dichloromethane, chloroform, acetic acid C1_g alkyl ester and mixtures thereof; the acetic acid C1_g alkyl ester is preferably an acetic acid C1_4 alkyl ester, more preferably selected from the group consisting of ethyl acetate, isopropyl acetate and, butyl acetate.

The product can be isolated by concentration of the extract that was washed with solvent (M- wash).

In another preferred embodiment, the reaction e resulting from reaction (Ml-reac) or the reaction mixture ing from reaction (M2-reac) can be, without above mentioned extraction with solvent (M-extract), acidiﬁed by mixing with an aqueous on of acid (M- acid). The mixture, that is thereby obtained, can be washed with solvent (M-wash), and the product can be isolated by concentration.

If the deprotonated medetomidine is to be isolated, a suspension or solution of the salt of medetomidine, preferably an aqueous suspension or solution of the salt of midine, can be basif1ed by addition of a base (M-basify) or of an aqueous on of base (M-basify); with base (M-basify) as defined above, also with all its preferred embodiments.

After the addition of base (M-basify), an aqueous phase can be ted with solvent (M- extract), followed by isolation of the product by concentration of the extract.

Preferably, any washing of any c phase after reaction (Ml-reac) or after reaction (M2- reac) can be done with water, with base (M-basify), with an aqueous solution of base (M- basify) or with brine.

Preferably, any extraction of any aqueous phase after reaction (Ml-reac) or after reaction (M2-reac) is done with solvent (M-extract).

Preferably, the on mixture after reaction (Ml-reac) or after on ac) is first concentrated under reduced pressure, then diluted with water and acidiﬁed with acid (M-acid) as described above, washed with solvent (M-wash), preferably solvent (M-wash) is e, basified with base (M-basify), preferably base (M-basify) is an aqueous solution ofNaHCOg, and then ted with solvent (M-extract), preferably solvent (M-extract) is selected from the group consisting of toluene, dichloromethane, isopropyl acetate and ethyl acetate; followed by isolation of the product by concentration of the extract.

In another preferred embodiment, compound of formula (XX) is puriﬁed after reaction (Ml- reac) or after reaction (M2-reac) by chromatography.

Any c phase can be dried, preferably over MgSO4 or NaZSO4.

Any tration is preferably done by distillation, preferably under reduced pressure.

The compound of formula (XX) can be purified, preferably by crystallization or distillation under reduced pressure, more preferably by crystallization from a mixture of cyclohexane and toluene, even more preferably from cyclohexane:toluene 99:1 v/v .

The compound of formula (XX) may also be converted into a salt by mixing with an acid (M- acid salt), acid (M-acid salt) is ably used as aqueous solution, acid (M-acid salt) is preferably selected from the group consisting of acetic acid, oxalic acid, HCl and H2804; then it can be isolated by filtration and purified by recrystallization in a solvent (M-cryst), solvent (M-cryst) is preferably selected from the group ting of water, ethanol, methanol, isopropanol, acetonitrile, hexane, cyclohexane, heptane, toluene, ethyl acetate and mixtures thereof; recrystallization can be repeated using a different solvent (M-cryst).

In another preferred embodiment, compound (XXI) is not isolated after on c).

Preferably, reaction (N-reac) and reaction (Ml-reac) are done in the same pot. More preferably, after reaction (N-reac) solvent (N-solv) is removed by evaporation, and reaction (Ml-reac) is done after ation of solvent (N-solv) and in the same pot as reaction (N- reac). nds of formula (XX), (XX-T), (XXI), (XXII), (XXIII) and (23) are chiral nds, and the formulae se any enantiomer as well as any mixture of enantiomers of the compounds of formula (XX), of formula (XX-T), of formula (XXI), of formula (XXII), of formula (XXIII) or of formula (23) respectively. omers can be separated by tional procedure known in organic chemistry, such as repeated crystallizations of the (+) ic acid salt in alcoholic media, as disclosed for compound of formula (XX) in Cordi et al., Synth. Commun. 1996, 26, 1585-1593. nds of a (XXV) are known compounds and can be prepared according to known methods.

The progress of any of the reactions reaction (Ml-reac), reaction (N-reac), reaction (Ql-reac) and reaction (Q2-reac) can be monitored by standard techniques, such as r 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 e 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 MgSO4 or , if not stated ise.

Compared to prior art, the method of the present invention offers several advantages: Importantly, the whole carbon framework of nd of formula (XX) is built in few chemical steps, using cheap reagents only. The few chemical steps obviously provide for a cost effective procedure. 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 ting 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 a (XXI) can be easily purified and obtained in a form of high odorous of fragrance purity or high nce 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 CDClg. Chemical shifts are expressed in parts per million referred to TMS and coupling nts (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 a In example 1 the THF was not dried with sodium. In example 2 NaH was used for this purpose.

Example 1: 2-(2,3-Dimethylphenyl)methyloxirane, compound of formula , metallation with butyllithium in THF To a solution of 1-brom0-2,3-dimethylbenzene (0.27 ml, 2.0 mmol) in THF (4.0 ml) at -78 CC was added n-butyllithium (2.0 ml of a 1.6 M solution in , 3.2 mmol). The mixture was stirred at -78 CC for 30 min, and then a solution of chloroacetone (0.24 ml, 3.0 mmol) in e (0.42 ml) was added dropwise within 20 min. The mixture was stirred at -78 0C for 1 h, and then allowed to warm to room temperature. Analysis of a sample after 3 h at room temperature indicated that the title epoxide was the main reaction product. After stirring at room temperature for 3 days the mixture was poured into water (20 ml), and the product was extracted with ethyl acetate (1 x 10 ml, 2 x 5 ml). The combined extracts were dried with MgSO4, and concentrated under d pressure to yield the title epoxide as an oil in quantitative yield. 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 (E1): 162, 147, 133, 117 (100).

Example 2: -Dimethylphenyl)methyloxirane, compound of formula (XXII), metallation with magnesium in THF To a suspension of magnesium (89 mg, 3.66 mmol) in THF (4.0 ml) were added NaH (81 mg, 60% in oil, 2.0 mmol), and after stirring at room temperature for 10 min, 1-bromo-2,3- dimethylbenzene (0.40 ml, 2.96 mmol). An exothermic reaction ensues, and the resulting mixture is stirred at room ature for 1 h. The mixture is then cooled to -20 CC, and a solution of chloroacetone (0.26 ml, 3.3 mmol) in toluene (0.63 ml) is dropwise added within min. The mixture is then stirred at room temperature for 2 h. A sample was worked up by mixing with water, extraction with ethyl acetate, and evaporation of the ethyl acetate with a stream of nitrogen. Analysis of the residue by 1H NMR indicated it to be a e of xylene and the title oxirane.

Example 3: 2-(2,3-Dimethylphenyl)pr0panal, nd of formula (XXI) 2-(2,3-Dimethylphenyl)methyloxirane, compound of formula (XXII), prepared according to example 1 (158 mg, 0.97 mmol), was dissolved in toluene (1.57 mL) and 2 (0.006 ml, 0.05 mmol) was added at room temperature. After 2 h at room temperature, a sample was mixed with solid NaHC03, ﬁltered, concentrated under reduced pressure, and the residue was analyzed by 1H NMR. The crude product consisted essentially of pure - dimethylphenyl)propanal. 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 4: 5-(1-(2,3-dimethylphenyl)ethyl)tosyl-4,5-dihydrooxazole, compound of formula (23) To a solution of compound of formula XXII (2.07 g, 12.8 mmol) in dichloromethane (10 ml) was added 2 (0.1 molar in EtzO, 4 ml, 0.4 mmol) within 4 h at room temperature. The mixture was stirred at room temperature for 1 h, and the solvent (dichloromethane) was then evaporated under reduced pressure. The residue was dissolved in ol (10 ml), and TosMIC (toluenesulfonylmethylisocyanide; 2.24 g, 11.5 mmol) and then N32C03 (102 mg, 0.96 mmol) were added. The mixture was stirred at room temperature for 1 h, and then diluted with water (5 ml). The mixture was stirred at room temperature for r 30 min, and then kept at 4 OC overnight. Filtration and drying d 3.1 g (75%) of compound of formula (23). 1H NMR(CDC13, 500 MHz): 1.28 (d, J = 7 Hz, 3H), 2.23 (s, 3H), 2.30 (s, 3H), 2.44 (s, 3H), 3.28 (m, 1H), 4.79 (m, 1H), 5.20 (m, 1H), 7.04 (s, 1H), 7.10 (m, 3H), 7.33 (d, J = 8 Hz, 2H), 7.73 (d, J = 8 Hz, 2H).

Example 5: Medetomidine, compound of formula (XX) Compound of formula (23) (3.16 g, 8.84 mmol), prepared according to e 4, was dissolved in ammonia-saturated ethanol (40 ml, containing approximately 160 mmol ammonia) and heated to 110 0C for 3 h. The mixture was then evaporated to dryness, and the residue was mixed with an aqueous, saturated solution ofNaHC03 (20 ml). The mixture was ted with toluene (2 x 20 ml), and the combined extracts were washed with water (2 x 20 ml). The combined extracts were then extracted with 10% aqueous HCl (3 x 20 ml), and the combined acidic extracts were basiﬁed with gaseous ammonia, and extracted with toluene (2 x 20 ml). The combined organic extracts were dried over Na2S04, and concentrated under reduced pressure, to yield compound of formula (XX) (1.57 g, 89%). 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, , 134.05, 134.60, 136.76,141.11,143.23.

MS (ESI): 201 [M+H]+ This product was redissolved in itrile (10 ml), and converted into a hydrochloride salt with trated aqueous hydrochloric acid (0.8 ml). The mixture was trated to s, and the residue was suspended in diethylether (30 ml), and stirred at room temperature overnight. Filtration and drying under reduced pressure yielded 1.55 g (74%) of compound of formula (XX) as hydrochloride salt.

Claims

The claims defining the invention are as follows:

1. A method for the ation of a compound of formula (XXI): 5 the method comprises two steps, the two steps are a step (Q1) and a step (Q2); step (Q1) comprises a reaction (Q1-reac); reaction (Q1-reac) is a reaction of nd of formula (XXV) with a reagent (Q1-reag) to provide a reaction product of reaction (Q1-reac); 10 R1 is Br, Cl, or I; t (Q1-reag) is selected from the group consisting of m, magnesium, aluminum, zinc, calcium, propylmagnesium chloride, propylmagnesium bromide, butyllithium and mixtures thereof; step (Q2) comprises a reaction (Q2-reac); 15 reaction (Q2-reac) is a on of the reaction product of reaction ac) with chloroacetone to provide a reaction product of reaction (Q2-reac); the reaction product of on (Q2-reac) is a compound of formula (XXII): which is converted to the compound of formula (XXI).

2. The method according to claim 1, wherein R1 is Br.

3. The method according to claim 1 or claim 2, wherein reagent (Q1-reag) is selected from the group consisting of lithium, magnesium, aluminum, isopropylmagnesium chloride, isopropylmagnesium bromide, llithium, sec-butyllithium, tert-butyllithium, and mixtures thereof.

4. The method according to any one of claims 1 to 3, wherein reaction (Q1-reac) is done in 5 the presence of a catalyst t); catalyst (Q1-cat) is selected from the group consisting of iodine, 1,2-dibromoethane, TiCl4, AlCl3, PbCl2, BiCl3, LiCl and mixtures thereof.

5. The method according to any one of claims 1 to 4, wherein the compound of formula 10 (XXI) is prepared in a step (N); step (N) is done after step (Q2); step (N) ses a reaction (N-reac); reaction (N-reac) is a reaction of a compound of formula (XXII) with a catalyst (N-cat); 15 catalyst (N-cat) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, camphorsulfonic acid, HCl, HBr, H2SO4, HNO3, H3PO4, HClO4, BCl3, BBr3, BF3OEt2, BF3SMe2, BF3THF, MgCl2, MgBr2, MgI2, AlCl3, 1-4 3, SnCl4, TiCl4, Ti(O-C1-4 alkyl)4, ZrCl4, Bi2O3, BiCl3, ZnCl2, PbCl2, FeCl3, ScCl3, NiCl2, )3, Yb(Cl)3, GaCl3, AlBr3, 20 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; compound of formula (XXII) is the reaction product of reaction (Q2-reac). 25

6. The method according to claim 5, wherein st (N-cat) is selected from the group consisting of acetic acid, formic acid, trifluoroacetic acid, methanesulfonic acid, ptoluenesulfonic acid, HCl, HBr, H2SO4, H3PO4, BCl3, 2, MgCl2, MgBr2, AlCl3, ZnCl2, Cu(BF4)2, aluminosilicate, acidic ion exchange resin, carbon treated with HCl, H2SO4 or HNO3, and mixtures thereof.

7. A method according to claim 1, ntially as hereinbefore described, with reference to any one of the Examples.