WO2006002721A1 - New 5-alkenone-3,3-dimethyl-benzoxepines derivatives useful for the preparation of antidiabetic pentadienoic acids - Google Patents

New 5-alkenone-3,3-dimethyl-benzoxepines derivatives useful for the preparation of antidiabetic pentadienoic acids Download PDF

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WO2006002721A1
WO2006002721A1 PCT/EP2005/005693 EP2005005693W WO2006002721A1 WO 2006002721 A1 WO2006002721 A1 WO 2006002721A1 EP 2005005693 W EP2005005693 W EP 2005005693W WO 2006002721 A1 WO2006002721 A1 WO 2006002721A1
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dimethyl
dihydrobenzoxepin
formula
buten
2one
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PCT/EP2005/005693
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French (fr)
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Michel Brunet
Guy Le Borgne
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Merck Patent Gmbh
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Priority to EP05747039A priority Critical patent/EP1758876A1/en
Publication of WO2006002721A1 publication Critical patent/WO2006002721A1/en

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D313/00—Heterocyclic compounds containing rings of more than six members having one oxygen atom as the only ring hetero atom
    • C07D313/02—Seven-membered rings
    • C07D313/06—Seven-membered rings condensed with carbocyclic rings or ring systems
    • C07D313/08—Seven-membered rings condensed with carbocyclic rings or ring systems condensed with one six-membered ring

Definitions

  • the present invention relates to 5-alkenone-3,3-dimethyl-benzoxepine derivatives and their use for the preparation of pentadienoic derivatives.
  • the above synthetic method involves a brominating step by means of NBS; this step may lead to several by-products, in particular in the presence of alkyl substituents on the molecule.
  • the compounds of formula (II) can be obtained by using simpler species, thus leading to potential compounds of greater diversity.
  • the invention provides an economical and efficient route for preparing the compounds of formula (II).
  • compounds of formula (II) are prepared from new compounds of formula (I).
  • the present invention is related to compounds of general formula (I) :
  • Each of Ri is independently chosen from a halogen atom; a cyano group; a nitro group; a carboxy group; an optionally halogenated (Ci-C 18 )alkoxycarbonyl group; an R 3 -CO-NH- or R a R b N-CO- group [in which R a and R b independently represent optionally halogenated (Ci-C 18 )alkyl; a hydrogen atom; (C 6 -Ci 0 )aryl or (C 6 -Cio)aryl(CrC 5 )alkyl (where the aryl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-Cs)alkyl group or by an optionally halogenated (Ci-Csjalkoxy group); (C 3 -C 12 )cycloalkyl optionally substituted by a halogen atom, by an optionally halogenated (Ci-C 5 )al
  • R represents a hydrogen atom or a (d-C 5 )alkyl or a (C 6 -C 10 )aryl, each being optionally substituted by a halogen atom, by an optionally halogenated (C- ⁇ -C 5 )alkyl group or by an optionally halogenated (C-i-CsJalkoxy group.
  • the formula (I) encompasses all types of geometric isomers and stereoisomers of the compounds of formula (I) or mixtures thereof.
  • Alkyl means an aliphatic hydrocarbon group which may be straight or branched, having 1 to 18 carbon atoms in the chain. Preferred alkyl groups have 1 to 12 carbon atoms in the chain.
  • Branched alkyl means that one or more lower alkyl groups such as methyl, ethyl or propyl are attached to a linear alkyl chain.
  • Lower alkyl means an alkyl group with 1 to about 4 carbon atoms in the chain which may be straight or branched.
  • alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, tert- butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl or octadecyl.
  • the alkyl group may be substituted by one or more halogen atoms representing thus an "halogenoalkyl" group.
  • Halogen atoms means fluorine, chlorine, bromine or iodine atoms. Preferred are fluorine, chlorine or bromine atoms and more preferred is fluorine atoms.
  • the "halogenoalkyl” groups may thus refer to “perfluoroalkyl", which means groups corresponding to the formula "-C n F 2n+I 11 wherein n represents 1 to 18.
  • perfluoroalkyl groups are pentafluoroethyl or trifluoro-methyl.
  • Alkoxy means an alkyl-O- group wherein the alkyl group is as herein described.
  • exemplary alkoxy groups include methoxy, ethoxy, isopropyloxy, butoxy and hexyloxy radicals.
  • Cycloalkyl means a non-aromatic mono- or multicyclic ring system of about 3 to 12 carbon atoms. Preferred ring sizes of the ring system include about 3 to 8 and more preferably 5 to 6 ring atoms.
  • the cycloalkyl is optionally substituted with one or more "ring system substituents" which may be the same or different, and are as defined herein.
  • Exemplary monocyclic cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl and the like.
  • Exemplary multicyclic cycloalkyl include 1-decalyn, norbornyl and the like.
  • Cycloalkenyl means a non-aromatic mono- or multicyclic ring system of about 3 to about 12 carbon atoms, preferably of about 5 to about 10 carbon atoms, and which contain at least one carbon-carbon double bond. Preferred ring size of rings of the ring system includes about 5 to about 6 ring atoms.
  • the cycloalkenyl is optionally substituted with one or more "ring system substituents" which may be the same or different, and are as defined herein.
  • Exemplary monocyclic cycloalkenyl include cyclopentenyl, cyclo-hexenyl, cycloheptenyl and the like.
  • An exemplary multicyclic cycloalkenyl is norbornylenyl.
  • Aryl means an aromatic monocyclic or multicyclic ring system of about 6 to about 10 carbon atoms.
  • the aryl is optionally substituted with one or more "ring system substituents" which may be the same or different and are as defined herein.
  • Exemplary aryl groups include phenyl or naphtyl, or substituted phenyl or substituted naphtyl.
  • Alkenyl means an aliphatic hydrocarbon group containing one or more carbon-carbon double bond and which may be straight or branched, having about 2 to about 12 carbon atoms in the chain, and more preferably about 2 to about 4 carbon atoms in the chain.
  • Branched alkenyl means that one or more lower alkyl or alkenyl groups such as methyl, ethyl or propyl are attached to a linear alkenyl chain.
  • Lower alkenyl means about 2 to about 4 carbon atoms in the chain, which may be straight or branched. The alkenyl group may be substituted by one or more halogen atoms.
  • Exemplary alkenyl groups include ethenyl, propenyl, n-butenyl, i- butenyl, 3-methylbut-2-enyl, n-pentenyl, heptenyl, octenyl, cyclohexyl-butenyl and decenyl.
  • Aryloxy means an aryl-O- group wherein the aryl group is as defined herein.
  • Exemplary groups include phenoxy and 2-naphtyloxy.
  • Aryloxycarbonyl means an aryl-O-CO- group wherein the aryl group is as defined herein.
  • exemplary aryloxycarbonyl groups include phenoxy-carbonyl and naphtoxycarbonyl.
  • Arylcarbonyl refers to an aryl-CO- group wherein the aryl group is as defined herein.
  • Exemplary arylcarbonyl group includes benzoyl.
  • the (C 6 -C 10 ) aryl, (C 3 -Ci 2 ) cycloalkyl, (C 3 -Ci 2 ) cycloalkenyl are optionally substituted by one or more "ring system substituents".
  • Ring system substituents mean substituents attached to aromatic or non- aromatic ring systems, inclusive of halogen atoms, an optionally halogenated (Cr C 5 ) alkyl, or an optionally halogenated (C 1 -C 5 ) alkoxy, halogen, alkyl and alkoxy being as defined herein,
  • aryl, cycloalkyl and cycloalkenyl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-C 5 )alkyl or by an optionally halogenated (CrC 5 )alkoxy
  • aryl, cycloalkyl, cycloalkenyl groups are optionally substituted by one or more substituents selected from the group consisting of :
  • halogenated means, in the context of the description, optionally substituted by one or more halogen atoms.
  • halogen atoms examples include fluorine, bromine and chlorine atoms.
  • optionally substituted halogenated (C 6 -Ci 0 ) arylcarbonyl include the groups ortho, meta or para chlorobenzoyl, or ortho, meta, para-bromobenzoyl group.
  • preferred optionally halogenated (C-i-Cis) alkyl include notably perfluoroalkyl groups such as trifluoromethyl.
  • optionally halogenated (CrC-is) alkoxy examples include notably optionally halogenated (CrC 6 ) alkoxy, particularly (C 1 -C 4 ) alkoxy such as methoxy, ethoxy, isopropyloxy, n-butoxy, isobutoxy.
  • Examples of particularly preferred optionally halogenated (C 6 -Cio) aryl include notably phenyl.
  • each of Ri independently represents a halogen atom, preferably chlorine or bromine atom; an halogenated (Ci-C 18 )alkyl group, preferably a perfluoro(Ci-C-i8)alkyl; a (Ci-C- ⁇ 8 )alkyl, preferably a methyl or isopropyl group; a optionally halogenated (CrCi 8 )alkoxy, preferably a perfluoroalkoxy; an optionally halogenated (C 6 -C 10 )aryl, preferably phenyl or halogenophenyl; and a (CrC-ie) alkoxy group, more preferably a (C 1 -C 4 ) alkoxy group and, most preferably, a methoxy group.
  • p is 1 or 2 and more preferably 1.
  • R may be located in position 6, 7, 8 or 9 on the benzoxepine structure, as represented hereafter:
  • R represents a (C 1 -C 5 ) alkyl.
  • Preferred compounds of formula (I) are chosen from:
  • a more preferred compound of formula (I) is (3E)-4-(3,3 ⁇ dimethyl-7-ethyl-2,3- dihydrobenzoxepin-5-yl)buten-2one (Compound IA) :
  • R, R-i, p are as defined in formula (I) and R' represents a hydrogen atom or a (C-i-C ⁇ Jalkyl or a (C 6 -Cio)aryl, optionally substituted by a halogen atom, by an optionally halogenated (Ci-C ⁇ )alkyl group or by an optionally halogenated (C 1 - C- 5 )alkoxy group.
  • each of Ri is independently chosen from a halogen atom; a cyano group; a nitro group; a carboxy group; an optionally halogenated (Ci-Cis)alkoxycarbonyl group; an R a -CO-NH- or R a R b N-CO- group [in which R 3 and Rb independently represent optionally halogenated (CrCi 8 )alkyl; a hydrogen atom; (C 6 -Ci 0 )aryl or (C6-Cio)aryl(Ci-C 5 )alkyl (where the aryl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-C 5 )alkyl group or by an optionally halogenated (C-i-C 5 )alkoxy group); (C 3 -Ci 2 )cycloalkyl optionally substituted by a halogen atom, by an optionally halogenated (C
  • R, Ri, p are defined as in formula (I).
  • the present invention is directed to a method for preparing compounds of formula (II):
  • R' preferably represents a hydrogen atom.
  • step a) comprises the following step according to scheme 2 :
  • AIk, AIk 1 , AIk", AIk' independently represent a (C1-C 5 ) alkyl group and R' is defined as above.
  • AIk, AIk', Ak independently represent a (C 1 -C 5 ) alkyl group ; preferably an ethyl group and R' is defined as above.
  • the ylid is prepared by reacting a base either with a compound (a) or with a compound (b).
  • the base used has to be sufficiently strong to remove an hydrogen atom in the alpha-position of the phosphorus.
  • the base is selected from the group consisting of alkali metal hydrides, alkali metal carbonates, such as potassium terbutylate, alkali metal amides, (C 1 -C 10 ) alkyllithium, and alkali metal alkoxides.
  • alkali metal hydrides such as sodium hydride and potassium hydride
  • alkali metal alkoxides such as sodium methoxide, sodium ethoxide and potassium tert-butoxide are particularly preferred.
  • Sodium hydride is particularly preferred.
  • the reaction of the base on the compounds (a) or (b) is effected in a solution, preferably in an aprotic solvent, and notably in a solvent able to dissolve the phosphonate (a) and respectively the phosphonium salt (b).
  • Suitable solvents are notably aprotic solvents, such as aromatic hydrocarbons, as for example benzene and toluene, ethers, such as diethylether, dioxane or tetrahydrofuran; aprotic polar solvents such as N,N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone or HMPT and mixtures thereof. Toluene is particularly preferred.
  • aprotic solvents such as aromatic hydrocarbons, as for example benzene and toluene
  • ethers such as diethylether, dioxane or tetrahydrofuran
  • aprotic polar solvents such as N,N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone or HMPT and mixtures thereof.
  • Toluene is particularly preferred.
  • the reaction of scheme 2 can take place over a wide range of temperatures, depending on the acidity of the compound (a), respectively (b), which means the ability to remove the hydrogen atom on the alpha-position with regard to the phosphorus.
  • the type of the base used directly influences the choice of the reaction temperature. Thus, the stronger the base is, the lower the reaction temperature is.
  • a temperature comprised between -10° and 100 0 C is generally suitable, preferably between room temperature and the boiling point of the solvent.
  • a stoichiometric amount of basis is generally required in scheme 2 to convert the phosphonate or the phosphonium salt into the corresponding ylid.
  • a slight excess of base may be used to ensure the total conversion of the compounds (a) or (b) into the ylid.
  • the molar ratio of the base relative to the compound (a), respectively (b) is maintained between 0,9 and 1 ,2, preferably between 0,9 and 1 ,1 , and more preferably between 0,95 and 1.
  • the concentration of the compound (a), respectively (b), in the reaction mixture is not critical according to the invention. The concentration may vary between 0,01 moi/L and 10 mo)/L, preferably between 0,1 and 1 mol/L
  • the ylid resulting from the reaction of the compound (a), respectively (b), with a base is performed before adding the compound of formula (I).
  • the phosphorus ylid is prepared from a phosphonate (a), diethylphosphonoacetate (formula a in which AIk, AIk', AIk" represent ethyl) is preferred.
  • the ylid is prepared by reacting diethylphosphonoacetate with sodium hydride in toluene.
  • the hydrolysis is performed under alkali conditions followed by acid conditions.
  • Alkali conditions may be achieved by using sodium hydroxide.
  • Suitable acids for the hydrolysis include inorganic acids, such as hydrochloric acid, sulphuric acid, nitric acid and phosphoric acid ; sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid and paratoluenesulfonic acid. Inorganic acids are most preferred and notably hydrochloric acid.
  • Excess amount of acid is generally used and the amount of acid is for example 5 to 10 moles relative to 1 mole of the ester.
  • the mixture is stirred, for example for 0.5 hour to 2 hours and preferably for 1 hour to 1.5 hour.
  • it has been found convenient to carry out the reaction at a temperature that does not exceed 4O 0 C, for example from about room temperature to about 40 0 C.
  • the time required for each reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period from about 0.5 hour to about 2 hours will usually be sufficient for the hydrolysis step.
  • the compounds thus prepared may be recovered from the reaction mixture by conventional means, for example the compounds may be recovered by distilling of the solvent from the reaction mixture or, if necessary, optionally after distilling of the solvent from the reaction mixture, pouring the residue into water, followed by extraction with a water-immiscible organic solvent and distilling of the solvent from the extract.
  • the product can, if desired, be further purified by various well known techniques, such as recrystallization, reprecipitation or the various chromatography techniques, notably column chromatography or preparative thin layer chromatography.
  • AIk' 7 with an halide of formula :
  • AIk, AIk', AIk", AIk'", R' are defined as above and Hal represents an halogen atom.
  • AIk, AIk', R' are defined as above and Hal represent an halogen atom.
  • the present inventors have also found the following particularly convenient method.
  • the invention provides a method for preparing the compounds of formula (I) comprising : reacting a compound of formula (III):
  • step i) consists in converting the compound of formula (III) into the corresponding sulfonic derivative of formula (IV):
  • the reaction is carried out in the presence of a Lewis acid or a base, such as pyridine, 2,6-diterbutylpyridine; 2,4,6-triterbutylpyridine; 4-Me-2,6- diterbutylpyridine; Na 2 C ⁇ 3 .
  • a Lewis acid or a base such as pyridine, 2,6-diterbutylpyridine; 2,4,6-triterbutylpyridine; 4-Me-2,6- diterbutylpyridine; Na 2 C ⁇ 3 .
  • Pyridine is especially preferred.
  • the amount of base is generally similar to the amount of the perhalogenoalkyl sulfonic derivative, preferably 0,9 to 1 ,1 moles relative to 1 mole of said derivative.
  • Suitable solvents include hydrocarbons, such as hexane, cyclohexane, benzene, toluene and xylene; aprotic polar solvents such as N,N-dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, pyridine, dichloromethane. Of these, dichloromethane are particularly preferred.
  • the reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, it has been found convenient to carry out the reaction at a temperature from about room temperature (2O 0 C) to 150 0 C, and more preferably of from 20 0 C to the boiling point of the solvent.
  • the molar ratio of the compound of formula (III) relative to the perhalogenoalkyl sulfonic derivative may vary from 2.0 to 6 equivalent, preferably from 4 to 5.
  • Step ii) The reaction under step ii) can be conducted by application or adaptation of the Heck reaction. Details of this well-known reaction can in particular be found in J. Org. Chem. 37, 2320 (1972).
  • the molar ration of compound (V) relative to compound of formula (IV) is from 1 ,2 to 3 equivalents.
  • the reaction is carried out in the presence of a base.
  • suitable basis examples include alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; (C 1 -Ci 0 ) alkyllithium compounds such as methyllithium, butyllithium, hexyllithium ; alkali metal alkoxides such as sodium methoxide and sodium ethoxide ; organic bases such as triethylamine; and alkali metal carbonates such as potassium carbonate and sodium carbonate.
  • alkali metal hydrides such as lithium hydride, sodium hydride and potassium hydride
  • (C 1 -Ci 0 ) alkyllithium compounds such as methyllithium, butyllithium, hexyllithium
  • alkali metal alkoxides such as sodium methoxide and sodium ethoxide
  • organic bases such as triethylamine
  • alkali metal carbonates such as potassium carbonate and sodium carbonate.
  • Organic bases such as triethylamine are particularly
  • reaction is palladium catalyzed; suitable catalysts include Pd(OCOCH 3 ) 2 , PdCI 2 , Pd(dba) 3 , Pd(PPh 3 ) 4 , Pd(PPh 3 )Cl 2 ; Pd(PPh 3 )CI 2 Js preferred.
  • a ligand such as PAr 3 , dppp, binap may also be used.
  • suitable solvents include hydrocarbons, such as hexane, cyclohexane, benzene, toluene and xylene; aprotic polar solvents such as N 1 N- dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, pyridine. Of these, dimethylformamide is particularly preferred.
  • the reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, it has been found convenient to carry out the reaction at a temperature from about room temperature (20 0 C) to 15O 0 C, preferably of from 2O 0 C to the boiling temperature of the solvent, more preferably 70-80°C.
  • the reaction can be conducted for a time sufficient to obtain a satisfactory reaction rate, usually between 1 and 10 hours.
  • Step iii) The compounds thus prepared may be recovered from the reaction mixture by conventional means, for example the compounds may be recovered by distilling of the solvent from the reaction mixture or, if necessary, optionally after distilling of the solvent from the reaction mixture, pouring the residue into water, followed by extraction with a water-immiscible organic solvent and distilling of the solvent from the extract. Additionally, the product can, if desired, be further purified by various well known techniques, such as recrystallization, reprecipitation or the various chromatography techniques, notably column chromatography or preparative thin layer chromatography.
  • the invention is illustrated by the following representative and non-limiting examples :
  • Trifluor ⁇ methane sulfonic anhydride (1.422 kg, 1.10 eq.) is added to a solution of 1 kg, 4.58 moles) of 3,3-dimethyl-7-ethyl-2,3,4,5-tetrahydrobenzoxepin- 5-one (HIA) in dichloromethane containing 0.3999 kg (1.10 eq.) of pyridine. The mixture is heated at reflux for 4 hours. The reaction mixture is cooled to 20 0 C and water is added. The organic layer is separated, washed with water and the dichloromethane is evaporated under vacuum. The crude oil (quantitative yield) is used without purification.
  • HOA 3,3-dimethyl-7-ethyl-2,3,4,5-tetrahydrobenzoxepin- 5-one
  • reaction mixture is cooled, diluted with water (11.00 liters) and toluene
  • the crude compound (VA) is put into a mixture of ethanol (5 liters) and water (5 liters). A solution of 0.480 liters of concentrated sodium hydroxide is added and then the mixture is heated at reflux for 2 hours (reaction followed by TLC). After partial evaporation at atmospheric pressure, the aqueous phase is washed twice with heptane. After acidification at Ph ⁇ 2 with chlorhydric acid, the aqueous phase is extracted with a mixture of heptane (4 liters) and toluene (0.2 liters). The organic phase is washed with water and partially evaporated at atmospheric pressure, lsopropanol is added, treated with charcoal and after cooling crystallized compound (HA) is filtered.

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Abstract

The present invention relates to new 5-alkenone-3,3-dimethyl-benzoxepines derivatives of formula (I), their use for the preparation of pentadienoic derivatives and their process of preparation.

Description

New 5-alkenone-3,3-dimethyl-benzoxepines derivatives useful for the preparation of antidiabetic pentadienoic acids
FIELD OF THE INVENTION The present invention relates to 5-alkenone-3,3-dimethyl-benzoxepine derivatives and their use for the preparation of pentadienoic derivatives.
BACKGROUND OF THE INVENTION δ-β.S-dimethyl^S-dihydrobenzoxepin-δ-yO^^-pentadienoic acid derivatives (formula II):
Figure imgf000002_0001
(II) are disclosed in WO00/39113 as useful for treating dyslipidemias, atherosclerosis and diabetes. In this application, compounds of formula Il are prepared according to the following scheme 1 :
Figure imgf000003_0001
Hydrolysis
Figure imgf000003_0002
Figure imgf000003_0003
Scheme 1
The above synthetic method involves a brominating step by means of NBS; this step may lead to several by-products, in particular in the presence of alkyl substituents on the molecule.
Additionally, the above method involves coupling with phosphonium or phosphonate derivatives of specific formulae: tf 5 R' o
Hal or
T1O.
:p-^r^
T-O'l 2 O R1 O
Due to the above specific formulae required, choice and availability of suitable phosphonium and phosphonate species are rather restricted. Further, this may limit the diversity of the structure of compounds of formula (II) which may possibly be prepared according to the above method.
Finally, the above method does not allow preparation of compounds substituted in the alpha-position relative to the acid group.
It now has been found a novel improved synthetic route for preparing the compounds of formula (II) which unexpectedly overcomes the above drawbacks of the prior art method.
Advantageously, the compounds of formula (II) can be obtained by using simpler species, thus leading to potential compounds of greater diversity.
As another advantage, the invention provides an economical and efficient route for preparing the compounds of formula (II). According to the present invention, compounds of formula (II) are prepared from new compounds of formula (I).
Thus, in one first object, the present invention is related to compounds of general formula (I) :
Figure imgf000004_0001
Each of Ri is independently chosen from a halogen atom; a cyano group; a nitro group; a carboxy group; an optionally halogenated (Ci-C18)alkoxycarbonyl group; an R3-CO-NH- or RaRbN-CO- group [in which Ra and Rb independently represent optionally halogenated (Ci-C18)alkyl; a hydrogen atom; (C6-Ci0)aryl or (C6-Cio)aryl(CrC5)alkyl (where the aryl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-Cs)alkyl group or by an optionally halogenated (Ci-Csjalkoxy group); (C3-C12)cycloalkyl optionally substituted by a halogen atom, by an optionally halogenated (Ci-C5)alkyl group or by an optionally halogenated (C1-Cs)BIkOXy group]; an optionally halogenated (CrC18)alkyl group; optionally halogenated (CrCi8)alkoxy; and (C6-Cio)aryl, (C6-C10)aryl(Ci-C5)alkyl, (C6-Cio)aryloxy, (C3-C12)cyclo-alkyl, (C3-Ci2)cycloalkenyl, (C3-Ci2)cycloalkyloxy, (C3-Ci2)cycloalkenyloxy ; (C-6-Ci0)aryloxycarbonyl or (C6-Ci0)arylcarbonyl ; in which the aryl, cycloalkyl and cycloalkenyl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-C5)alkyl or by an optionally halogenated (Ci-C5)alkoxy; p represents 0, 1 , 2, 3 or 4;
R represents a hydrogen atom or a (d-C5)alkyl or a (C6-C10)aryl, each being optionally substituted by a halogen atom, by an optionally halogenated (C-ι-C5)alkyl group or by an optionally halogenated (C-i-CsJalkoxy group.
The formula (I) encompasses all types of geometric isomers and stereoisomers of the compounds of formula (I) or mixtures thereof.
As used above and throughout the description of the invention, the following terms, unless otherwise indicated, shall be understood to have the following meanings. "Alkyl" means an aliphatic hydrocarbon group which may be straight or branched, having 1 to 18 carbon atoms in the chain. Preferred alkyl groups have 1 to 12 carbon atoms in the chain.
"Branched alkyl" means that one or more lower alkyl groups such as methyl, ethyl or propyl are attached to a linear alkyl chain. "Lower alkyl" means an alkyl group with 1 to about 4 carbon atoms in the chain which may be straight or branched.
Exemplary alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, tert- butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl or octadecyl. The alkyl group may be substituted by one or more halogen atoms representing thus an "halogenoalkyl" group.
"Halogen atoms" means fluorine, chlorine, bromine or iodine atoms. Preferred are fluorine, chlorine or bromine atoms and more preferred is fluorine atoms. The "halogenoalkyl" groups may thus refer to "perfluoroalkyl", which means groups corresponding to the formula "-CnF2n+I 11 wherein n represents 1 to 18.
Examples of perfluoroalkyl groups are pentafluoroethyl or trifluoro-methyl.
"Alkoxy" means an alkyl-O- group wherein the alkyl group is as herein described. Exemplary alkoxy groups include methoxy, ethoxy, isopropyloxy, butoxy and hexyloxy radicals.
"Cycloalkyl" means a non-aromatic mono- or multicyclic ring system of about 3 to 12 carbon atoms. Preferred ring sizes of the ring system include about 3 to 8 and more preferably 5 to 6 ring atoms. The cycloalkyl is optionally substituted with one or more "ring system substituents" which may be the same or different, and are as defined herein. Exemplary monocyclic cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl and the like.
Exemplary multicyclic cycloalkyl include 1-decalyn, norbornyl and the like. "Cycloalkenyl" means a non-aromatic mono- or multicyclic ring system of about 3 to about 12 carbon atoms, preferably of about 5 to about 10 carbon atoms, and which contain at least one carbon-carbon double bond. Preferred ring size of rings of the ring system includes about 5 to about 6 ring atoms. The cycloalkenyl is optionally substituted with one or more "ring system substituents" which may be the same or different, and are as defined herein. Exemplary monocyclic cycloalkenyl include cyclopentenyl, cyclo-hexenyl, cycloheptenyl and the like. An exemplary multicyclic cycloalkenyl is norbornylenyl.
"Aryl" means an aromatic monocyclic or multicyclic ring system of about 6 to about 10 carbon atoms. The aryl is optionally substituted with one or more "ring system substituents" which may be the same or different and are as defined herein. Exemplary aryl groups include phenyl or naphtyl, or substituted phenyl or substituted naphtyl.
"Alkenyl" means an aliphatic hydrocarbon group containing one or more carbon-carbon double bond and which may be straight or branched, having about 2 to about 12 carbon atoms in the chain, and more preferably about 2 to about 4 carbon atoms in the chain.
"Branched alkenyl" means that one or more lower alkyl or alkenyl groups such as methyl, ethyl or propyl are attached to a linear alkenyl chain. "Lower alkenyl" means about 2 to about 4 carbon atoms in the chain, which may be straight or branched. The alkenyl group may be substituted by one or more halogen atoms. Exemplary alkenyl groups include ethenyl, propenyl, n-butenyl, i- butenyl, 3-methylbut-2-enyl, n-pentenyl, heptenyl, octenyl, cyclohexyl-butenyl and decenyl. "Aryloxy" means an aryl-O- group wherein the aryl group is as defined herein.
Exemplary groups include phenoxy and 2-naphtyloxy.
"Aryloxycarbonyl" means an aryl-O-CO- group wherein the aryl group is as defined herein. Exemplary aryloxycarbonyl groups include phenoxy-carbonyl and naphtoxycarbonyl. "Arylcarbonyl" refers to an aryl-CO- group wherein the aryl group is as defined herein.
Exemplary arylcarbonyl group includes benzoyl.
The (C6-C10) aryl, (C3-Ci2) cycloalkyl, (C3-Ci2) cycloalkenyl are optionally substituted by one or more "ring system substituents". "Ring system substituents" mean substituents attached to aromatic or non- aromatic ring systems, inclusive of halogen atoms, an optionally halogenated (Cr C5) alkyl, or an optionally halogenated (C1-C5) alkoxy, halogen, alkyl and alkoxy being as defined herein,
The wording "in which the aryl, cycloalkyl and cycloalkenyl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-C5)alkyl or by an optionally halogenated (CrC5)alkoxy" means that the aryl, cycloalkyl, cycloalkenyl groups are optionally substituted by one or more substituents selected from the group consisting of :
- halogen atoms ; - alkyl groups optionally substituted by one or more halogen atoms, and
- alkoxy groups optionally substituted by one or more halogen atoms.
The wording "optionally halogenated" means, in the context of the description, optionally substituted by one or more halogen atoms.
Examples of preferred halogen atoms include fluorine, bromine and chlorine atoms.
Examples of optionally substituted halogenated (C6-Ci0) arylcarbonyl include the groups ortho, meta or para chlorobenzoyl, or ortho, meta, para-bromobenzoyl group. Examples of preferred optionally halogenated (C-i-Cis) alkyl include notably perfluoroalkyl groups such as trifluoromethyl.
Examples of preferred optionally halogenated (CrC-is) alkoxy include notably optionally halogenated (CrC6) alkoxy, particularly (C1-C4) alkoxy such as methoxy, ethoxy, isopropyloxy, n-butoxy, isobutoxy.
Examples of particularly preferred optionally halogenated (C6-Cio) aryl include notably phenyl.
According to a preferred aspect, each of Ri independently represents a halogen atom, preferably chlorine or bromine atom; an halogenated (Ci-C18)alkyl group, preferably a perfluoro(Ci-C-i8)alkyl; a (Ci-C-ι8)alkyl, preferably a methyl or isopropyl group; a optionally halogenated (CrCi8)alkoxy, preferably a perfluoroalkoxy; an optionally halogenated (C6-C10)aryl, preferably phenyl or halogenophenyl; and a (CrC-ie) alkoxy group, more preferably a (C1-C4) alkoxy group and, most preferably, a methoxy group. Preferably, p is 1 or 2 and more preferably 1.
R may be located in position 6, 7, 8 or 9 on the benzoxepine structure, as represented hereafter:
Figure imgf000008_0001
(I)
Preferably, R represents a (C1-C5) alkyl. Preferred compounds of formula (I) are chosen from:
(3E)-4-(3,3-dimethyl-7-ethyl-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-methoxy-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7,8-dimethoxy-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-8-chloro-2,3-dihydrobenzoxepin-5-yl)buten-2one ; (3E)-4-(3,3-dimethyl-7-chloro-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-bromo-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-8-chloro-7-fluoro-2,3-dihydrobenzoxepin-5-yl)buten-
2one; (3E)-4-(3,3-dimethyl-7-fluoro-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-trifluoromethyl-2,3-dihydrobenzoxepin-5-yl)buten-
2one;
(3E)-4-(3,3-dimethyi-7-phenyl-2,3-dihydrobenzoxepiπ-5-yl)buten-2one ; (3E)-4-(3,3-dimethyl-7-methyl-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-9-methoxy-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7,8-dimethyl-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-8-(4-fluorophenyl)-2,3-dihydrobenzoxepin-5-yl)buten-
2one ; (3E)-4-(3,3-dimethyl-8-methoxy-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-isopropyl-2,3-dihydroben2oxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-trifluoromethoxy-2,3-dihydrobenzoxepin-5-yl)buten-
2one ;
(2E)-3-(3,3-dimethyl - 7-methoxy - 2,3-dihydrobenzoxepin-5-yi) - 1 -phenyl - propen-1-one ;
(1 E)-1-(3,3-dimethyl - 8-methoxy - 2,3-dihydrobenzoxepin-5-yl) -hexen-3- one ;
(1E)-1-(3,3-dimethyl - 7-methoxy - 2,3-dihydrobeπzoxepin-5-yl) -octen-3- one ; (1 E)-1-(3,3-dimethy! - 8-methoxy - 2,3-dihydrobenzoxepin-5-yl) -octen-3- one ;
as well as their geometric isomers and stereoisomers or mixtures thereof.
A more preferred compound of formula (I) is (3E)-4-(3,3~dimethyl-7-ethyl-2,3- dihydrobenzoxepin-5-yl)buten-2one (Compound IA) :
Figure imgf000009_0001
(IA) as well as its geometric isomers and stereoisomers or mixtures thereof. Methods for preparing compounds of formula (11) starting from compounds of formula (0
According to the invention, the compounds of formula (}) are used for the preparation of compounds of formula (II):
Figure imgf000010_0001
CO in which R, R-i, p are as defined in formula (I) and R' represents a hydrogen atom or a (C-i-CδJalkyl or a (C6-Cio)aryl, optionally substituted by a halogen atom, by an optionally halogenated (Ci-Cδ)alkyl group or by an optionally halogenated (C1- C-5)alkoxy group.
Compounds of formula (II), in which R' is a (CrCsJalkyl or a (C6~CiO)aryl, optionally substituted by a halogen atom, by an optionally halogenated (Ci-C5)alkyl group or by an optionally halogenated (Ci-C5)alkoxy group could not be prepared according to method disclosed in WO00/39113 and, are, thus, novel.
According to a second aspect, the present invention therefore concerns new compounds of formula (II):
Figure imgf000010_0002
(II) in which each of Ri is independently chosen from a halogen atom; a cyano group; a nitro group; a carboxy group; an optionally halogenated (Ci-Cis)alkoxycarbonyl group; an Ra-CO-NH- or RaRbN-CO- group [in which R3 and Rb independently represent optionally halogenated (CrCi8)alkyl; a hydrogen atom; (C6-Ci0)aryl or (C6-Cio)aryl(Ci-C5)alkyl (where the aryl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-C5)alkyl group or by an optionally halogenated (C-i-C5)alkoxy group); (C3-Ci2)cycloalkyl optionally substituted by a halogen atom, by an optionally halogenated (C1-C5)alkyl group or by an optionally halogenated (Ci-C5)alkoxy group]; an optionally halogenated (C-|-C18)alkyl group; optionally halogenated (C1-Ciβ)alkoxy; and (C6-Ci0)aryl, (C6-Cio)aryl(Ci-C5)alkyl, (C6-Cio)aryloxy, (C3-Ci2)cyclo-alkyl, (C3-Ci2)cycloalkenyl, (C3-Ci2)cycloalkyloxy, (C3-Ci2)cycloalkenyloxy ; (C6-C10)aryloxycarbonyl or (C6-Ci0)arylcarbonyl ; in which the aryl, cycloalkyl and cycloalkenyl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-Cs)alkyl or by an optionally halogenated (C-,-C5)alkoxy; p represents 0, 1 , 2, 3 or 4; R represents a hydrogen atom or a (C-t-C5)alkyl or a (C6-C10)aryl, each being optionally substituted by a halogen atom, by an optionally halogenated (CrC5)alkyl group or by an optionally halogenated (Ci-C5)alkoxy group; R' is a (C-ι-C5)alkyl or a (C6-CiO)aryl, each being optionally substituted by a halogen atom, by an optionally halogenated (C1-C5)alkyl group or by an optionally halogenated (Ci-C5)alkoxy group, as well as their geometric isomers and stereoisomers or mixtures thereof.
Preferred R, Ri, p are defined as in formula (I).
Thus , in another object, the present invention is directed to a method for preparing compounds of formula (II):
Figure imgf000011_0001
(H) from compounds of formula (I)
Figure imgf000012_0001
(I) in which R, R-i, p, R' are defined as above, comprising : a) carrying out a Wittig reaction or a Homer-Emmons / Wadsworth- Emmons on a compound of formula (I), b) hydrolyzing the resulting product ; and optionally c) isolating the obtained compound of formula (K).
In this reaction, R' preferably represents a hydrogen atom.
The reaction of step a) comprises the following step according to scheme 2 :
Figure imgf000012_0002
(H) Scheme 2 The reaction implemented in scheme 2 can be carried out by applying or adapting either a Wittig reaction or a Horner-Emmons / Wadsworth-Emmons reaction. These reactions are both well-known in the art and typically involve the preparation of a reactive ylid. For any further information on that subject, reference may be made to G. Wittig, U. Schδllkopf, Ber. 87, 1318 (1954) ; G. Wittig, W. Haag, ibid. 88, 1654 (1955) ; L. Homer et al., Ber. 91 , 61 (1958) ; idem et al., ibid. 92, 2499 (1959) ; W. S. Wadsworth, Jr., W. D. Emmons, J. Am. Chem. Soc. 83, 1733 (1961).
When the ylid is prepared from a phosphonium salt (compound b), the reaction implemented is a Wittig reaction.
Compounds b have the following formula:
b in which AIk, AIk1, AIk", AIk'" independently represent a (C1-C5) alkyl group and R' is defined as above.
When the ylid is prepared from a phosphonate (compound a), the reaction is called a Horner-Emmons or Wadsworth-Emmons reaction. Compounds a have the following formula:
Figure imgf000013_0002
a wherein AIk, AIk', Ak" independently represent a (C1-C5) alkyl group ; preferably an ethyl group and R' is defined as above.
Under scheme 2, the ylid is prepared by reacting a base either with a compound (a) or with a compound (b). The base used has to be sufficiently strong to remove an hydrogen atom in the alpha-position of the phosphorus.
Typically, the base is selected from the group consisting of alkali metal hydrides, alkali metal carbonates, such as potassium terbutylate, alkali metal amides, (C1-C10) alkyllithium, and alkali metal alkoxides. In the context of the invention, alkali metal hydrides such as sodium hydride and potassium hydride, and alkali metal alkoxides such as sodium methoxide, sodium ethoxide and potassium tert-butoxide are particularly preferred. Sodium hydride is particularly preferred. The reaction of the base on the compounds (a) or (b) is effected in a solution, preferably in an aprotic solvent, and notably in a solvent able to dissolve the phosphonate (a) and respectively the phosphonium salt (b).
Examples of suitable solvents are notably aprotic solvents, such as aromatic hydrocarbons, as for example benzene and toluene, ethers, such as diethylether, dioxane or tetrahydrofuran; aprotic polar solvents such as N,N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone or HMPT and mixtures thereof. Toluene is particularly preferred.
The reaction of scheme 2 can take place over a wide range of temperatures, depending on the acidity of the compound (a), respectively (b), which means the ability to remove the hydrogen atom on the alpha-position with regard to the phosphorus. The type of the base used directly influences the choice of the reaction temperature. Thus, the stronger the base is, the lower the reaction temperature is.
When the base is an alkali metal alkoxide, a temperature comprised between -10° and 1000C is generally suitable, preferably between room temperature and the boiling point of the solvent.
A stoichiometric amount of basis is generally required in scheme 2 to convert the phosphonate or the phosphonium salt into the corresponding ylid. However, a slight excess of base may be used to ensure the total conversion of the compounds (a) or (b) into the ylid. Thus, the molar ratio of the base relative to the compound (a), respectively (b), is maintained between 0,9 and 1 ,2, preferably between 0,9 and 1 ,1 , and more preferably between 0,95 and 1. The concentration of the compound (a), respectively (b), in the reaction mixture is not critical according to the invention. The concentration may vary between 0,01 moi/L and 10 mo)/L, preferably between 0,1 and 1 mol/L
According to a preferred embodiment, the ylid resulting from the reaction of the compound (a), respectively (b), with a base is performed before adding the compound of formula (I). Preferably, the phosphorus ylid is prepared from a phosphonate (a), diethylphosphonoacetate (formula a in which AIk, AIk', AIk" represent ethyl) is preferred.
According to a preferred embodiment, the ylid is prepared by reacting diethylphosphonoacetate with sodium hydride in toluene.
The above reaction of scheme 2 is followed by the step b) of hydrolyzing the obtained ester into the desired acid compound of formula (II).
Preferably, the hydrolysis is performed under alkali conditions followed by acid conditions.
Alkali conditions may be achieved by using sodium hydroxide. Suitable acids for the hydrolysis include inorganic acids, such as hydrochloric acid, sulphuric acid, nitric acid and phosphoric acid ; sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid and paratoluenesulfonic acid. Inorganic acids are most preferred and notably hydrochloric acid.
Excess amount of acid is generally used and the amount of acid is for example 5 to 10 moles relative to 1 mole of the ester.
In that context, the mixture is stirred, for example for 0.5 hour to 2 hours and preferably for 1 hour to 1.5 hour. In that context, it has been found convenient to carry out the reaction at a temperature that does not exceed 4O0C, for example from about room temperature to about 400C.
The time required for each reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period from about 0.5 hour to about 2 hours will usually be sufficient for the hydrolysis step.
In optional step c), the compounds thus prepared may be recovered from the reaction mixture by conventional means, for example the compounds may be recovered by distilling of the solvent from the reaction mixture or, if necessary, optionally after distilling of the solvent from the reaction mixture, pouring the residue into water, followed by extraction with a water-immiscible organic solvent and distilling of the solvent from the extract. Additionally, the product can, if desired, be further purified by various well known techniques, such as recrystallization, reprecipitation or the various chromatography techniques, notably column chromatography or preparative thin layer chromatography.
The above phosphonium derivatives of formula b are either commercially available or may be readily prepared by known methods by reacting a phosphine of formula:
AIk1" N AIk11- P+
AIk'7 with an halide of formula :
Figure imgf000016_0001
in which AIk, AIk', AIk", AIk'", R' are defined as above and Hal represents an halogen atom.
The above phosphonate derivatives of formula a are either commercially available or may be readily prepared by known methods, such as the Arbuzov method, wherein for instance, when AIk' and AIk" are identical, a phosphate P(OAIk')3 is reacted with an halide of formula:
Figure imgf000016_0002
in which AIk, AIk', R' are defined as above and Hal represent an halogen atom.
Methods for preparing the compounds of formula (I) The compounds useful according to the invention may be prepared by the application or adaptation of known methods, by which are meant methods used heretofore or described in the literature, for example those described by R. C. Larock in Comprehensive Organic Transformations, VCH Publishers, 1989.
The present inventors have also found the following particularly convenient method.
Thus, in a further aspect, the invention provides a method for preparing the compounds of formula (I) comprising : reacting a compound of formula (III):
Figure imgf000017_0001
(III) with a perhalogenoalkyl sulfonic derivative; ii) carrying out a Heck reaction on the resulting product ; and optionally iii) isolating the obtained compound of formula (I). This can be illustrated by the following scheme 3 :
k reaction
Figure imgf000017_0002
(D
Scheme 3
The reaction of step i) consists in converting the compound of formula (III) into the corresponding sulfonic derivative of formula (IV):
Figure imgf000017_0003
(IV) This reaction requires the presence of a perhalogenoalkyl sulfonic derivative. Preferred derivatives include trifluoromethane sulfonic anhydride.
Preferably, the reaction is carried out in the presence of a Lewis acid or a base, such as pyridine, 2,6-diterbutylpyridine; 2,4,6-triterbutylpyridine; 4-Me-2,6- diterbutylpyridine; Na2Cθ3. Pyridine is especially preferred.
The amount of base is generally similar to the amount of the perhalogenoalkyl sulfonic derivative, preferably 0,9 to 1 ,1 moles relative to 1 mole of said derivative.
There is no particular restriction on the nature of the solvent to be used, provided that it has no adverse effect on the reaction or on the reagent involved.
Examples of suitable solvents include hydrocarbons, such as hexane, cyclohexane, benzene, toluene and xylene; aprotic polar solvents such as N,N-dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, pyridine, dichloromethane. Of these, dichloromethane are particularly preferred. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, it has been found convenient to carry out the reaction at a temperature from about room temperature (2O0C) to 1500C, and more preferably of from 200C to the boiling point of the solvent. The molar ratio of the compound of formula (III) relative to the perhalogenoalkyl sulfonic derivative may vary from 2.0 to 6 equivalent, preferably from 4 to 5.
Step ii) The reaction under step ii) can be conducted by application or adaptation of the Heck reaction. Details of this well-known reaction can in particular be found in J. Org. Chem. 37, 2320 (1972).
The obtained compound of formula (IV) obtained in step i) is reacted with a compound of formula (V):
Figure imgf000018_0001
(V) in which R is defined as in formula (I). This step can be carried out in situ, straight after step i), or after isolating compound (IV), or preferably on the crude product after evaporating the solvent.
The molar ration of compound (V) relative to compound of formula (IV) is from 1 ,2 to 3 equivalents. The reaction is carried out in the presence of a base.
Examples of suitable basis include alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; (C1-Ci0) alkyllithium compounds such as methyllithium, butyllithium, hexyllithium ; alkali metal alkoxides such as sodium methoxide and sodium ethoxide ; organic bases such as triethylamine; and alkali metal carbonates such as potassium carbonate and sodium carbonate. Organic bases such as triethylamine are particularly preferred.
The reaction is palladium catalyzed; suitable catalysts include Pd(OCOCH3)2, PdCI2, Pd(dba)3, Pd(PPh3)4, Pd(PPh3)Cl2; Pd(PPh3)CI2 Js preferred.
A ligand such as PAr3, dppp, binap may also be used. There is no particular restriction on the nature of the solvent to be used, provided that it has no adverse effect on the reaction or on the reagent involved.
Examples of suitable solvents include hydrocarbons, such as hexane, cyclohexane, benzene, toluene and xylene; aprotic polar solvents such as N1N- dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, pyridine. Of these, dimethylformamide is particularly preferred.
The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, it has been found convenient to carry out the reaction at a temperature from about room temperature (200C) to 15O0C, preferably of from 2O0C to the boiling temperature of the solvent, more preferably 70-80°C.
The reaction can be conducted for a time sufficient to obtain a satisfactory reaction rate, usually between 1 and 10 hours.
Step iii) The compounds thus prepared may be recovered from the reaction mixture by conventional means, for example the compounds may be recovered by distilling of the solvent from the reaction mixture or, if necessary, optionally after distilling of the solvent from the reaction mixture, pouring the residue into water, followed by extraction with a water-immiscible organic solvent and distilling of the solvent from the extract. Additionally, the product can, if desired, be further purified by various well known techniques, such as recrystallization, reprecipitation or the various chromatography techniques, notably column chromatography or preparative thin layer chromatography. The invention is illustrated by the following representative and non-limiting examples :
Example 1:
3,3-dimethyl-5-trifluoromethansulfonyloxy-7-ethyl-2,3-dihydro- benzoxepine ( formula (IV) : R = CH3 and R1= C2H5 ; (IVA )) :
Trifluorσmethane sulfonic anhydride (1.422 kg, 1.10 eq.) is added to a solution of 1 kg, 4.58 moles) of 3,3-dimethyl-7-ethyl-2,3,4,5-tetrahydrobenzoxepin- 5-one (HIA) in dichloromethane containing 0.3999 kg (1.10 eq.) of pyridine. The mixture is heated at reflux for 4 hours. The reaction mixture is cooled to 200C and water is added. The organic layer is separated, washed with water and the dichloromethane is evaporated under vacuum. The crude oil (quantitative yield) is used without purification.
Example 2: (3E)-4-(3,3-dimethyl-7-ethyl-2,3-dihydrobenzoxepin-5-yl)-buten-2-one
(formula (I) : R = CH3 and R1= C2H5 ; (IA )) :
The crude oil of example 1 is dissolved in dimethylformamide (3 liters). 0.417 Kg (1.3 eq.) of methylvinylketone, dichloro bis(triphenylphosphine)palladium (0.003 kg) and triethylamine (0.834 kg (1.8 eq.) are added to this solution. The mixture is heated between 70-750C for 5 hours.
The reaction mixture is cooled, diluted with water (11.00 liters) and toluene
(2.20 liters). The organic phase is separated, washed with diluted chlorhydric acid and then water. The toluene phase is washed, filtered on silica and dried. After evaporation of the solvent under vacuum 1.189 kg (yield 96 %) of compound (IA) are obtained.
1H RMN δ ppm : 1.15 (6H,t) , 2.3 (3H, s) , 2.6 (2H, m) , 3.8 (2H, s) , 6.15 (H, s) , 6.3 (1 H, d) , 7.1 (3H, m) , 7.5 (1 H, d). Example 3 :
Ethyl ester of (2E,4E)-5-(3,3-dimethyl-7-ethyl-2,3-benzoixepin-5-yl)-3- methylpenta-2,4-dienoic acid (R = CH3 and R1= C2H5)
1 ,658 kg (2 eq.) of ethyle diethylphosphonoacetate are added at room temperature to a suspension of 0.288 kg (1.95 eq.) of sodium hydride in toluene. After 1 hour, 1kg (3.699 moles) of compound (IA) are added and the mixture is heated at 55-600C for 3 hours (the reaction is followed by TLC).
Water (2 liters) is added. The aqueous phase is discarded and the organic phase is filtered on silica. Toluene is then distillated under vacuum at a temperature up to 7O0C and the crude (VA) is used without further purification for the preparation of compound (UlA).
Example 4 :
(2E,4E)-5-(3>3-dimethyl-7-ethyl-2,3-benzoxepin-5-yl)-3-methylpenta-2,4- dienoic acid (formula (II) : R = CH3 and Ri= C2H5 ; (HA))
The crude compound (VA) is put into a mixture of ethanol (5 liters) and water (5 liters). A solution of 0.480 liters of concentrated sodium hydroxide is added and then the mixture is heated at reflux for 2 hours (reaction followed by TLC). After partial evaporation at atmospheric pressure, the aqueous phase is washed twice with heptane. After acidification at Ph<2 with chlorhydric acid, the aqueous phase is extracted with a mixture of heptane (4 liters) and toluene (0.2 liters). The organic phase is washed with water and partially evaporated at atmospheric pressure, lsopropanol is added, treated with charcoal and after cooling crystallized compound (HA) is filtered. The crude compound is purified in methanol/water (90/10). The crystallized (HA) is filtered at -10°C , washed with aqueous ethanol and dried at 65°C to give (VA), yield =45% identical to compound 35B of EP 1140893.

Claims

CLAIMS 1. Compounds of general formula (I) :
Figure imgf000022_0001
each of Ri is independently chosen from a halogen atom; a cyano group; a nitro group; a carboxy group; an optionally halogenated (Ci-Cis)alkoxycarbonyl group; an R3-CO-NH- or R3RbN-CO- group [in which R3 and Rb independently represent optionally halogenated (Ci-C18)alkyl; a hydrogen atom; (C6-C10)aryl or (C6-Cio)aryl(Ci-C5)alkyl (where the aryl parts are optionally substituted by a halogen atom, by an optionally halogenated (CrC5)alkyl group or by an optionally halogenated (Ci-C5)alkoxy group); (C3-Ci2)cycloalkyl optionally substituted by a halogen atom, by an optionally halogenated (C-)-C5)alkyl group or by an optionally halogenated (Ci-C5)alkoxy group]; an optionally halogenated (Ci-C18)alkyl group; optionally halogenated (Ci-Ciδ)alkoxy; and (C6-Ci0)aryl, (C6-Cio)aryl(Ci-C5)alkyl, (C6-Cio)aryloxy, (C3-Ci2)cyclo-alkyl, (C3-C 12)cycloalkenyl, (C3-Ci2)cycloalkyloxy, (C3-Ci2)cycloalkenyloxy ; (C6-Ci0)aryloxycarbonyl or (C6-Ci0)arylcarbonyl ; in which the aryl, cycloalkyl and cycloalkenyl parts are optionally substituted by a halogen atom, by an optionally halogenated (Ci-Cs)alkyl or by an optionally halogenated (CrC5)alkoxy; p represents 0, 1 , 2, 3 or 4; R represents a hydrogen atom or a (Ci-C5)alkyl or a (C6-CiO)aryl, each being optionally substituted by a halogen atom, by an optionally halogenated (CrC5)alkyl group or by an optionally halogenated (CrCs)alkoxy group, as well as their geometric isomers and stereoisomers of the compounds of formula (I) or mixtures thereof.
2. Compounds of formula (I) according to claim 1 , wherein each of Ri independently represents a halogen atom; an halogenated (Ci-Cis)alkyl group; a (C-ι-Cig)a)ky); a optionally halogenated (Ci-Ci8)alkoxy; an optionally halogenated (C6-Cio)aryl; and a (CrC18) alkoxy group.
3. Compounds according to claim 1 or 2 wherein each of Ri independently represents a chlorine or bromine atom, a perfluoro(Ci-Cis)alkyl, a methyl or isopropyl group, a perfluoroalkoxy, a phenyl or halogenophenyl, a methoxy group.
4. Compounds according to claim 1 , 2 or 3 wherein each of Ri independently represents methoxy group.
5. Compounds according to anyone of the preceding claims, wherein p is 1 or 2.
6. Compounds according to anyone of the preceding claims, wherein R is a (C1-C5) alkyl group.
7. Compounds according to anyone of the preceding claims chosen from:
(3E)-4-(3,3-dimethyl-7-ethyl-2,3-dihydrobenzoxepin-5-yl)buten-2one ; (3E)-4-(3,3-dimethyl-7-methoxy-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7,8-dimethoxy-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-8-chloro-2,3-dihydrobenzoxepin-5-yl)buten~2one ;
(3E)-4-(3,3-dimethyl-7-chIoro-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-bromo-2,3-dihydrobenzoxepin-5-yl)buten-2one ; (3E)-4-(3,3-dimethyl-8-chloro-7-fluoro-2,3-dihydrobenzoxepin-5-yl)buten-
2one;
(3E)-4-(3,3-dimethyl-7-fluoro-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-trifluoromethyl-2,3-dihydrobenzoxepin-5-yl)buten-
2one; (3E)-4-(3,3-dimethyl-7-phenyl-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-methyl-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-9-methoxy-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7,8-dimethyl-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-8-(4-fiυorophenyl)-2,3-dihydrobenzoxepin-5-yl)buten- 2one ;
(3E)-4-(3,3-dimethyl-8-methoxy-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-isopropyl-2,3-dihydrobenzoxepin-5-yl)buten-2one ;
(3E)-4-(3,3-dimethyl-7-trifluoromethoxy-2,3-dihydrobenzoxepin-5-yl)buten-
2one ; (2E)-3-(3,3-dimethyl-7-methoxy -2,3-dihydrobenzoxepin-5-yl)-1 -phenyl - propen-1-one ;
(1E)-1-(3,3-dimethyl-8-methoxy-2,3-dihydrobenzoxepin-5-yl)-hexen-3-one ; (1E)-1-(3,3-dimethyl-7-methoxy-2,3-dihydrobenzoxepin-5-yl)-octen-3-oπe ; (1 E)-1-(3,3-dimethyl - 8-methoxy - 2,3-dihydrobenzoxepin-5-yl)-octen-3- one ; as well as their geometric isomers and stereoisomers or mixtures thereof.
8. Compounds according to anyone of the preceding claims which is: (3E)-4-(3,3-dimethyl-7-ethyl-2,3-dihydrobenzoxepin-5-yl)buten-2one.
9. Process of preparation of compounds of formula (I) according to anyone of the preceding claims comprising :
(i) reacting a compound of formula (III):
Figure imgf000024_0001
(III) with a perhalogenoalky) sulfonic derivative; (ii) carrying out a Heck reaction on the resulting product.
10. Process according to claim 9, wherein step i) comprises converting the compound of formula (III) into the corresponding sulfonic derivative of formula (IV):
3
Figure imgf000024_0002
(IV) in the presence of a perhalogenoalkyl sulfonic derivative.
11. Process according to claim 9 or 10, wherein said derivative is trifluoromethane sulfonic anhydride.
12. Process according to anyone of claims 9 to 11 , wherein step i) is conducted in the presence of a Lewis acid or a base.
13. Process according to claim 12, wherein said Lewis acid or base is chosen from pyridine, 2,6-diterbutylpyridine; 2,4,6-triterbutylpyridine; 4-Me-2,6- diterbutylpyridine; Na2CO3.
14. Process according to claim 12 or 13, wherein said Lewis acid or base is pyridine.
15. Process according to anyone of claims 9 to 14, wherein step ii) is carried out according to a Heck reaction.
16. Process according to claim 15, wherein said reaction is conducted with a compound of formula (V):
Figure imgf000025_0001
(V) in which R is defined as in formula (I).
17. Process according to anyone of claims 9 to 16 wherein step ii) is carried out in situ, straight after step i), or after isolating compound (IV), or on the crude product of step i) after evaporating the solvent.
18. Process according to anyone of claims 15 to 17, wherein step ii) is carried out in the presence of a base.
19. Process according to anyone of claims 15 to 18, wherein step ii) is carried out in the presence of a palladium catalyst.
20. Process according to claim 19, wherein said catalyst is Pd(PPh3)CI2.
21. Process according to anyone of claims 9 to 20 which further comprises the step of isolating the obtained compound of formula (I).
22. Process of preparation of a compound of formula (II):
Figure imgf000026_0001
(H) in which R, R-i, p are defined as in anyone of claims 1 to 7 and R' represents a hydrogen atom or a (C-ι-C5)alkyl or a (C6-Cio)ary(, each being optionally substituted by a halogen atom, by an optionally halogenated (Ci-C5)alkyl group or by an optionally halogenated (Ci-Cs)alkoxy group comprising : a) carrying out a Wittig reaction or a Horner-Emmons / Wadsworth- Emmons on a compound of formula (I), as defined in anyone of claims 1 to 8, b) hydrolyzing the resulting product.
23. Process according to claim 22, wherein R' represents a hydrogen atom.
24. Process according to claim 22 or 23, wherein step a) is carried out with a compound of formula b
Figure imgf000026_0002
b in which AIk, AIk', AIk", AIk'" independently represent a (Ci-C5) alkyl group and R1 is defined as in claim 22, or of formula a:
Figure imgf000026_0003
wherein AIk, AIk', Ak" independently represent a (CrC5) group and R' is defined as in claim 22.
25. Process according to anyone of claims 22 to 24, wherein a base is reacted either with a compound (a) or with a compound (b).
26. Process according to claim 25, wherein said base is chosen from alkali metal hydrides and alkali metal alkoxides.
27. Process according to anyone of claims 21 to 26, wherein step b) comprises the step of hydrolyzing the obtained product into the desired acid compound of formula (II).
28. Process according to claim 27, wherein said hydrolysis is conducted under acid conditions.
29. Process according to anyone of claims 22 to 28, which further comprises the step of isolating the obtained compound of formula (II).
30. Compounds of formula (II):
Figure imgf000027_0001
OD in which
R, Ri, p are as defined in anyone of claims 1 to 8, and R' is a (CrCsJalkyl or a (C6-Ci0)aryl, each being optionally substituted by a halogen atom, by an optionally halogenated (Ci-Cs)alkyl group or by an optionally halogenated (CrCs)alkoxy group, as well as their geometric isomers and stereoisomers or mixtures thereof.
PCT/EP2005/005693 2004-06-25 2005-05-27 New 5-alkenone-3,3-dimethyl-benzoxepines derivatives useful for the preparation of antidiabetic pentadienoic acids WO2006002721A1 (en)

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WO2000039113A1 (en) * 1998-12-29 2000-07-06 Merck Patent Gmbh Benzopyrans and benzoxepines, pharmaceutical compositions comprising them and preparation process

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