HK1136817A - Process for the synthesis of ethers of aromatic acids - Google Patents

Description

Method for synthesizing ether of aromatic acid

This patent application claims priority to U.S. provisional application 60/876, 570 filed on 21/12/2006, which is incorporated in its entirety as part of this document for various purposes.

Technical Field

The present invention relates to the production of ethers of hydroxyaromatic acids which are highly valuable for a variety of uses, such as for use as intermediates or as monomers in the production of polymers.

Background

Ethers of aromatic acids are used as intermediates and auxiliaries in the manufacture of many valuable substances, including pharmaceuticals and compounds which play a role in crop protection, and also as monomers in the production of High-performance rigid polymers, such as linear rigid oligo (2-aminobenzamides) for electrical device applications [ Wu et al, Organic Letters (2004), 6(2), pages 229 to 232 ] and polypyridobisimidazoles et al [ see, for example, Beers et al, High-performance fabrics (2000), pages 93 to 155 ].

The existing process for the production of 2, 5-dialkoxy-and 2, 5-diaryloxy terephthalic acids involves the stepwise alkylation of 2, 5-dihydroxyterephthalic acid to form the corresponding 2, 5-alkoxy-and 2, 5-diaryloxy terephthalates, followed by dealkylation of the esters to the acid. The n-hydroxy aromatic acid may be converted to an n-alkoxy aromatic acid by contacting the hydroxy aromatic acid with an n-alkyl sulphate under basic conditions. One suitable method of carrying out this conversion reaction is described in austria patent 265,244. The yield is moderate to low, the yield is low and a two-step process is required.

Thus, there remains a need for processes that can economically produce ethers of aromatic acids with high yields and high yields in small and large scale operations as well as in batch and continuous operations.

Detailed Description

The invention disclosed herein includes: a process for the preparation of ethers of aromatic acids, a process for the preparation of products into which such ethers can be converted, the use of such processes, and the products obtained and obtainable by such processes.

One embodiment of the process herein provides a process for preparing an ether of an aromatic acid, which ether can be described by the structure of formula I

Wherein Ar is C₆-C₂₀A monocyclic or polycyclic aryl nucleus, R is a monovalent organic group, n and m are each independently nonzero values, and n + m is less than or equal to 8; the method comprises the following steps

(a) The halogenated aromatic acid with the structure of the formula II

Wherein each X is independently Cl, Br or I, and Ar, n and m are as described above, with:

(i) containing the alcoholate RO^-M⁺(wherein M is Na or K), wherein the polar protic, polar aprotic, or alcoholic solvent is ROH or a solvent less acidic than ROH;

(ii) a copper (I) or copper (II) source; and

(iii) copper-coordinating diketone ligands as described by the structure of formula III

Wherein A is

R¹And R²Each independently selected from substituted and unsubstituted C₁-C₁₆N-alkyl, iso-alkyl and tertiary alkyl; and substituted and unsubstituted C₆-C₃₀Aryl and heteroaryl;

R³is selected from H; substituted and unsubstituted C₁-C₁₆N-alkyl, iso-alkyl and tertiary alkyl; substituted and unsubstituted C₆-C₃₀Aryl and heteroaryl; and a halogen;

R⁴、R⁵、R⁶and R⁷Each independently is H or substituted or unsubstituted C₁-C₁₆N-alkyl, iso-alkyl or tertiary alkyl; and n is 0 or 1;

to form a reaction mixture;

(b) heating the reaction mixture to form an m-basic salt of the product of step (a) as described by the structure of formula IV;

(c) optionally, separating the m-basic salt of formula IV from the reaction mixture in which the m-basic salt of formula IV is formed; and

(d) contacting the m-basic salt of formula IV with an acid to thereby form an ether of an aromatic acid.

Another embodiment of the present invention provides a process for preparing a compound, monomer, oligomer or polymer by preparing an ether of an aromatic acid generally described by the structure of formula I, and then subjecting the ether so produced to a reaction (including a multi-step reaction) to prepare the compound, monomer, oligomer or polymer.

Detailed Description

The present invention provides a process for preparing ethers of aromatic acids having improved yields and yields, which ethers can be described by the structure of formula I

Wherein Ar is C₆-C₂₀A monocyclic or polycyclic aryl nucleus, R is a monovalent organic group, n and m are each independently nonzero values, and n + m is less than or equal to 8; the method comprises the following steps

One embodiment of the process herein is carried out by the steps of:

(a) the halogenated aromatic acid with the structure of the formula II

Wherein each X is independently Cl, Br or I, and Ar, n and m are as described above, with:

(i) containing the alcoholate RO^-M⁺(wherein M is Na or K), wherein the polar protic, polar aprotic, or alcoholic solvent is ROH or a solvent less acidic than ROH;

(ii) a copper (I) or copper (II) source; and

(iii) copper-coordinating diketone ligands, e.g. as described by the structure of formula III

Wherein A is

R¹And R²Each independently selected from substituted and unsubstituted C₁-C₁₆N-alkyl, iso-alkyl and tertiary alkyl; and substituted and unsubstituted C₆-C₃₀Aryl and heteroaryl;

R³is selected from H; substituted and unsubstituted C₁-C₁₆N-alkyl, iso-alkyl and tertiary alkyl; substituted and unsubstituted C₆-C₃₀Aryl and heteroaryl; and a halogen;

R⁴、R⁵、R⁶and R⁷Each independently is H or substituted or unsubstituted C₁-C₁₆N-alkyl, iso-alkyl or tertiary alkyl; and n is 0 or 1;

to form a reaction mixture;

(b) heating the reaction mixture to form an m-basic salt of the product of step (a) as described by the structure of formula IV;

(c) optionally, separating the m-basic salt of formula IV from the reaction mixture in which the m-basic salt of formula IV is formed; and

(d) contacting the m-basic salt of formula IV with an acid to thereby form an ether of an aromatic acid.

In formulae I, II and IV, Ar is C₆-C₂₀A monocyclic or polycyclic aryl nucleus; n and m are each independently a non-zero value, and n + m is less than or equal to 8; r is a monovalent organic group; and in formula II, each X is independently Cl, Br, or I.

Is represented by the formula

The radicals represented are n + m-valent C₆-C₂₀A monocyclic or polycyclic aryl nucleus formed by removal of n + m hydrogens from different carbon atoms on the aromatic ring or rings (when the structure is polycyclic). The group "Ar" may be substituted or unsubstituted; when unsubstituted, it contains only carbon and hydrogen.

One example of a suitable Ar group is phenylene as shown below, where n ═ m ═ 1.

One preferred Ar group is shown below, where n ═ m ═ 2.

The monovalent group R is a monovalent organic group. R is preferably C₁-C₁₂Alkyl or aryl. R is more preferably C₁-C₄Alkyl or phenyl. Examples of particularly suitable R groups include, without limitation, methyl, ethyl, isopropyl, isobutyl, and phenyl. Several other non-limiting examples of R are shown below:

X＝N，S

X＝C，N

as used herein, the term "m-basic salt" is a salt formed from an acid that contains m acid groups with replaceable hydrogen atoms per molecule.

Various halogenated aromatic acids to be used as starting materials in the process of the present invention are commercially available. For example, 2-bromobenzoic acid is available from Aldrich Chemical Company (Milwaukee, Wisconsin). However, it can be synthesized by oxidation of benzyl bromide as described by Sasson et al in Journal of Organic Chemistry (1986), 51(15), 2880 to 2883. Other useful halogenated aromatic acids include, without limitation, 2, 5-dibromobenzoic acid, 2-bromo-5-nitrobenzoic acid, 2-bromo-5-methylbenzoic acid, 2-chlorobenzoic acid, 2, 5-dichlorobenzoic acid, 2-chloro-3, 5-dinitrobenzoic acid, 2-chloro-5-methylbenzoic acid, 2-bromo-5-methoxybenzoic acid, 5-bromo-2-chlorobenzoic acid, 2, 3-dichlorobenzoic acid, 2-chloro-4-nitrobenzoic acid, 2, 5-dichloroterephthalic acid, 2-chloro-5-nitrobenzoic acid, 2, 5-dibromoterephthalic acid, and 2, 5-dichloroterephthalic acid, all of which are commercially available. The halogenated aromatic acid is preferably 2, 5-dibromoterephthalic acid or 2, 5-dichloroterephthalic acid.

Other halogenated aromatic acids which may be used as starting materials in the process of the present invention include those shown in the left column of the following table, wherein X ═ Cl, Br or I, and wherein the ethers of the corresponding aromatic acids thus prepared by the process of the present invention are shown in the right column:

in step (a), contacting a halogenated aromatic acid with: containing the alcoholate RO^-M⁺Wherein R is as defined above and M is Na or K; a copper (I) or copper (II) source; and a diamine ligand coordinated to copper.

The alcohol may be ROH, which is preferred, or may be an alcohol that is less acidic than ROH. For example, if R is phenyl such that ROH is phenol, one non-limiting example of a less acidic alcohol that can be used in step (a) is isopropanol. Examples of suitable alcohols include, without limitation, methanol, ethanol, isopropanol, isobutanol, and phenol, provided that the alcohol is ROH or an alcohol that is less acidic than ROH.

The solvent may be a polar protic solvent or a polar aprotic solvent or a mixture of a protic solvent and a polar aprotic solvent. As used herein, a polar solvent is a solvent in which the constituent molecules exhibit a non-zero dipole moment. As used herein, a polar protic solvent is a polar solvent whose component molecules contain O-H or N-H bonds. As used herein, a polar aprotic solvent is a polar solvent in which the constituent molecules do not contain O-H or N-H bonds. Examples of the polar solvent other than the alcohol suitable for use herein include tetrahydrofuran, N-methylpyrrolidone, dimethylformamide, and dimethylacetamide.

In step (a), the halogenated aromatic acid is preferably used in a total of about n + m to n + m +1 equivalents of alcoholate RO^-M⁺The amount of halogenated aromatic acid per equivalent is contacted with the alcoholate. Between m and m +1 equivalents are required for the formation of the m-basic salt, and between n and n +1 equivalents are required for the substitution reaction. The total amount of alcoholate preferably does not exceed m + n + 1. The total amount of alcoholate is also preferably not less than m + n to avoid reduction reactions. As used herein, an "equivalent" is that which will react with one mole of hydrogen ionsAlcoholate RO of^-M⁺The number of moles of (a). For an acid, one equivalent refers to the number of moles of acid that will provide one mole of hydrogen ions.

As described above, in step (a), the halogenated aromatic acid is also contacted with a copper (I) or (II) source in the presence of a diketone ligand that coordinates to copper. The copper source and ligand may be added sequentially to the reaction mixture or may be combined separately (e.g., in aqueous or acetonitrile solution) and added together.

The copper source is a Cu (I) salt, a Cu (II) salt, or a mixture thereof. Examples include, without limitation, CuCl, CuBr, CuI, Cu₂SO₄、CuNO₃、CuCl₂、CuBr₂、CuI₂、CuSO₄And Cu (NO)₃)₂. The copper source may be selected according to the nature of the halogenated aromatic acid used. For example, if the starting halogenated aromatic acid is bromobenzoic acid, CuCl, CuBr, CuI, Cu₂SO₄、CuNO₃、CuCl₂、CuBr₂、CuI₂、CuSO₄And Cu (NO)₃)₂May be included in the available selections. If the starting halogenated aromatic acid is chlorobenzoic acid, then CuBr, CuI, CuBr₂And CuI₂May be included in the available selections. For most systems, CuBr and CuBr₂Is generally the preferred option. The amount of copper used is typically from about 0.1 to about 5 mole percent based on moles of halogenated aromatic acid.

The ligand may be a diketone as described by the structure of formula III

Wherein A is

R¹And R²Each independently selected from substituted and unsubstituted C₁-C₁₆N-alkyl, iso-alkyl and tertiary alkyl; and substituted and unsubstituted C₆-C₃₀Aryl and heteroaryl;

R³is selected from H; substituted and unsubstituted C₁-C₁₆N-alkyl, iso-alkyl and tertiary alkyl; substituted and unsubstituted C₆-C₃₀Aryl and heteroaryl; and a halogen;

R⁴、R⁵、R⁶and R⁷Each independently is H or substituted or unsubstituted C₁-C₁₆N-alkyl, iso-alkyl or tertiary alkyl; and is

N is 0 or 1.

When used with respect to an alkyl or aryl group in a diketone as described above, the term "unsubstituted" means that the alkyl or aryl group contains no atoms other than carbon and hydrogen. However, in substituted alkyl or aryl, one or more O or S atoms may optionally be substituted for any one or more carbon atoms in the chain or ring, provided that the resulting structure does not contain an-O-or-S-moiety, and that no more than one heteroatom is bonded to any carbon atom. In a preferred embodiment, R³Is H.

In one embodiment, a diketone suitable for use herein as a ligand is 2, 2 ', 6, 6' -tetramethyl-3, 5-heptanedione (formula V):

other diketones suitable for use as ligands herein include, without limitation, 2, 4-pentanedione and 2, 3-pentanedione.

Ligands suitable for use herein may be selected from any one or more or all of the ligands described by name or structure above.

The various copper sources and ligands suitable for use herein may be prepared by methods known in the art or may be obtained commercially from suppliers such as Alfa Aesar (Ward Hill, Massachusetts), City Chemical (West Haven, Connecticut), Fisher Scientific (Fairlawn, new jersey), Sigma-Aldrich (st. louis, Missouri) or stanford materials (alio Viejo, California).

In various embodiments, the ligand may be provided in an amount of from about 1 to about 8, preferably from about 1 to about 2, molar equivalents of ligand per mole of copper. In those and other embodiments, the ratio of molar equivalents of ligand to molar equivalents of halogenated aromatic acid may be less than or equal to about 0.1. As used herein, the term "molar equivalent" refers to the number of moles of ligand that will interact with one mole of copper.

In step (b), the reaction mixture is heated to form an m-basic salt of the product of step (a) as described by the structure of formula IV:

the reaction temperature of steps (a) and (b) is preferably between about 40 and about 120 ℃, more preferably between about 75 and about 95 ℃. The time required for step (a) is generally from about 0.1 to about 1 hour. The time required for step (b) is generally from about 0.1 to about 1 hour. During the reaction, oxygen removal may be required. Before optional step (c) and before acidification in step (d) is carried out, the solution is typically cooled.

The m-basic salt of the ether of the aromatic acid is then contacted with an acid in step (d) to convert it to the hydroxy aromatic acid product. Any acid of sufficient strength to protonate the m-basic salt is suitable. Examples include, without limitation: hydrochloric acid, sulfuric acid and phosphoric acid.

In one embodiment, the copper (I) or copper (II) source is selected from CuBr, CuBr₂And mixtures thereofA compound; the ligand is selected from 2, 2 ', 6, 6' -tetramethyl-3, 5-heptanedione, 2, 4-pentanedione and 2, 3-pentanedione; and the copper (I) or copper (II) source is bound to two molar equivalents of the ligand.

The above process also enables the efficient and effective synthesis of products prepared from the resulting ethers of aromatic acids, such as compounds, monomers, or oligomers or polymers thereof. These prepared materials may have one or more of ester functionality, ether functionality, amide functionality, imide functionality, imidazole functionality, thiazole functionality, oxazole functionality, carbonate functionality, acrylate functionality, epoxide functionality, urethane functionality, acetal functionality, and anhydride functionality.

Representative reactions involving materials prepared using the process of the present invention or derivatives of such materials include, for example, the process set forth in U.S. Pat. No. 3,047,536 (which is incorporated in its entirety as part of this document for all purposes), under nitrogen and in the presence of 0.1% Zn₃(BO₃)₂In the case of (1-methylnaphthalene), a polyester is prepared from an ether of an aromatic acid and diethylene glycol or triethylene glycol. Similarly, ethers of aromatic acids are suitable for copolymerization with dibasic acids and glycols to produce heat stable polyesters according to the method set forth in U.S. Pat. No. 3,227,680 (incorporated in its entirety as part of this document for all purposes), wherein representative conditions include formation of a prepolymer in butanol at 200-250 ℃ in the presence of titanium tetraisopropoxide, followed by solid phase polymerization at 280 ℃ under a pressure of 0.08 mmHg.

Ethers of aromatic acids can also be polymerized in polycondensation with the tris-hydrochloride monohydrate of tetraaminopyridine in strong polyphosphoric acid under reduced pressure under slow heating to above 100 ℃ to about 180 ℃ and then precipitated in water as disclosed in US 5,674,969 (incorporated in its entirety as part of this document for various purposes); or by mixing the monomers at a temperature of about 50 ℃ to about 110 ℃, then forming oligomers at 145 ℃, and then reacting the oligomers at about 160 ℃ to about 250 ℃, as disclosed in U.S. provisional application 60/665,737 (incorporated herein in its entirety for all purposes) filed on 28.3.2005 as WO 2006/104974. The polymer thus produced may be a pyridobisimidazole-2, 6-diyl (2, 5-dialkoxyphenylene) polymer or a pyridobisimidazole-2, 6-diyl (2, 5-diaryloxyphenylene) polymer, such as a poly (1, 4- (2, 5-diaryloxy) phenylene-2, 6-pyrido [2, 3-d: 5, 6-d' ] diimidazole) polymer. However, their pyridobisimidazole moiety may be substituted with any one or more of benzodiimidazole, benzodithiazole, benzodioxazole, pyridobisthiazole and pyridobisoxazole; and their 2, 5-dialkyl p-phenylene moieties can be substituted with alkyl or aryl ethers of one or more of isophthalic acid, terephthalic acid, 2, 5-pyridinedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, 4' -diphenyldicarboxylic acid, 2, 6-quinolinedicarboxylic acid, and 2, 6-bis (4-carboxyphenyl) pyridobisimidazole, wherein such ethers are produced according to the methods disclosed herein.

The polymer prepared in this way may, for example, comprise one or more of the following units:

pyridobisimidazole-2, 6-diyl (2, 5-dialkoxyphenylene) and/or pyridobisimidazole-2, 6-diyl (2, 5-diphenoxyparaphenylene) units;

a unit selected from the group consisting of pyridobisimidazole-2, 6-diyl (2, 5-dimethoxyp-phenylene), pyridobisimidazole-2, 6-diyl (2, 5-diethoxyphenylene), pyridobisimidazole-2, 6-diyl (2, 5-dipropoxyphenylene), pyridobisimidazole-2, 6-diyl (2, 5-dibutyloxy-p-phenylene), and pyridobisimidazole-2, 6-diyl (2, 5-diphenoxyp-phenylene);

pyridodithiazol-2, 6-diyl (2, 5-dialkoxyphenylene) and/or pyridodithiazol-2, 6-diyl (2, 5-diphenoxyparaphenylene) units;

a unit selected from the group consisting of pyridodithiazole-2, 6-diyl (2, 5-dimethoxyp-phenylene), pyridodithiazole-2, 6-diyl (2, 5-diethoxyphenylene), pyridodithiazole-2, 6-diyl (2, 5-dipropoxyphenylene), pyridodithiazole-2, 6-diyl (2, 5-dibutyloxy-p-phenylene) and pyridodithiazole-2, 6-diyl (2, 5-diphenoxy-p-phenylene);

pyridobisoxazole-2, 6-diyl (2, 5-dialkoxy p-phenylene) and/or pyridobisoxazole-2, 6-diyl (2, 5-diphenoxy p-phenylene) units;

a unit selected from the group consisting of pyridobisoxazole-2, 6-diyl (2, 5-dimethoxyp-phenylene), pyridobisoxazole-2, 6-diyl (2, 5-diethoxyphenylene), pyridobisoxazole-2, 6-diyl (2, 5-dipropoxyphenylene), pyridobisoxazole-2, 6-diyl (2, 5-dibutyloxy-p-phenylene), and pyridobisoxazole-2, 6-diyl (2, 5-diphenoxyp-phenylene);

a benzodiimidazole-2, 6-diyl (2, 5-dialkoxy-p-phenylene) and/or a benzodiimidazole-2, 6-diyl (2, 5-diphenoxy-p-phenylene) unit;

a unit selected from the group consisting of benzodiimidazole-2, 6-diyl (2, 5-dimethoxyp-phenylene), benzodiimidazole-2, 6-diyl (2, 5-diethoxyphenylene), benzodiimidazole-2, 6-diyl (2, 5-dipropoxyphenylene), benzodiimidazole-2, 6-diyl (2, 5-dibutyloxy-p-phenylene) and benzodiimidazole-2, 6-diyl (2, 5-diphenoxy-p-phenylene);

a benzodithiazole-2, 6-diyl (2, 5-dialkoxyphenylene) and/or a benzodithiazole-2, 6-diyl (2, 5-diphenoxyparaphenylene) unit;

a unit selected from the group consisting of benzodithiazole-2, 6-diyl (2, 5-dimethoxyp-phenylene), benzodithiazole-2, 6-diyl (2, 5-diethoxyphenylene), benzodithiazole-2, 6-diyl (2, 5-dipropoxyphenylene), benzodithiazole-2, 6-diyl (2, 5-dibutyloxy-p-phenylene) and benzodithiazole-2, 6-diyl (2, 5-diphenoxy-p-phenylene);

a benzodioxazole-2, 6-diyl (2, 5-dialkoxy-p-phenylene) and/or a benzodioxazole-2, 6-diyl (2, 5-diphenoxy-p-phenylene) unit; and/or

A unit selected from the group consisting of benzodioxazole-2, 6-diyl (2, 5-dimethoxyp-phenylene), benzodioxazole-2, 6-diyl (2, 5-diethoxyphenyl), benzodioxazole-2, 6-diyl (2, 5-dipropoxyphenyl), benzodioxazole-2, 6-diyl (2, 5-dibutoxyphenyl) and benzodioxazole-2, 6-diyl (2, 5-diphenoxyp-phenylene).

Examples

The advantageous properties and effects of the method of the invention can be seen in the laboratory examples described below. The embodiments of the methods on which the examples are based are representative only, and the selection of those embodiments to illustrate the invention does not indicate that conditions, arrangements, modes, steps, techniques, configurations or reactants not described in the examples are not suitable for practicing the methods, nor does it indicate that subject matter not described in the examples is excluded from the scope of the appended claims and equivalents thereof.

As used herein, the term "conversion" refers to the amount of reactants consumed, expressed as a fraction or percentage of the theoretical amount. The term "selectivity" of a product P refers to the mole fraction or mole percentage of P in the final product mixture. Thus, the conversion multiplied by the selectivity is equal to the maximum "yield" of P; the actual or "net" yield will generally be slightly less than the maximum yield due to losses of the sample during activities such as separation, handling, drying, etc. The term "purity" refers to the actual percentage of the specified substance in the resulting isolated sample.

The abbreviations have the following meanings: "h" means hour, "mL" means milliliter, "g" means gram, "MeOH" means methanol, "mg" means milligram, "mmol" means millimole, and "molequiv" means molar equivalent.

Example 1

4.2g (77mmol) of sodium methoxide were combined with 125g of anhydrous methanol in an air and moisture-free environment, followed by addition of 5g (15mmol) of 2, 5-dibromoterephthalic acid. Under nitrogen, 103mg (0.03mol equiv) of CuBr₂And 0.06mol equiv of 2, 2 ', 6, 6' -tetramethyl-3, 5-heptanedione were separately combined, followed by adding anhydrous methanol to the solution. The solution is then added to form a reaction mixture. The reaction mixture was heated to reflux under stirring for 8h, while maintaining a nitrogen atmosphere. After cooling, the product was filtered off, washed with hot MeOH and dried to yield a white solid as the disodium salt. The isolated salt is then acidified with hydrochloric acid. The purity is greater than 95% and the yield of the net separation is greater than 90%.

Each formula shown herein describes all of the different individual compounds that can be formed in that formula by: (1) selecting one of the variable groups, substituents or numerical coefficients within the specified range while all other variable groups, substituents or numerical coefficients remain unchanged, and (2) performing the same selection within the specified range to select each other variable group, substituent or numerical coefficient while others remain unchanged. In addition to the selection of only one member of the group described by a range within the indicated range of any variable group, substituent or numerical coefficient, a plurality of compounds may be described by selecting more than one but less than all of the members of the entire group of groups, substituents or numerical coefficients. When a selection is made within the indicated range for any variable group, substituent or numerical coefficient, the subgroup comprises: (i) only one member of the entire group described by the scope, or (ii) more than one but less than all members of the entire group, then the selected member is selected by omitting those members of the entire group that were not selected to form the subgroup. In this case, the compound or compounds may be characterized by the definition of one or more variable groups, substituents or numerical coefficients, which relate to the entire group of variables within the specified range, but in which the members omitted from forming the subgroup are not within the entire group.

Where a range of numerical values is recited herein, the range includes the endpoints thereof, and all the individual integers and fractions within the range, and also includes each of the narrower ranges therein formed by all the various possible combinations of those endpoints and internal integers and fractions to form subgroups of the larger group of numerical values within the range, to the same extent as if each of those narrower ranges were explicitly recited. Where a range of numerical values is described herein as being greater than a stated value, the range is nevertheless limited and is bounded on its upper end by a value operable in the context of the invention as described herein. When a range of values is described herein as being less than a stated value, the range is still bounded on its lower limit by non-zero values.

In this specification, unless explicitly stated otherwise or indicated to the contrary by the context of usage, amounts, sizes, ranges and other quantities and characteristics recited herein, particularly when modified by the term "about," may be, but need not be, exact, and may also be approximate and/or larger or smaller (as desired) than the recited value, reflecting deviations, conversion factors, rounding off, measurement error and the like, and include within the recited value those values outside the recited value that have equivalent function and/or operation within the context of the present invention as the recited value.

It should be understood that when an embodiment of this invention is stated or described as comprising, including, containing, having, being composed of or consisting of certain features, one or more features may be present in the embodiment in addition to those explicitly stated or described, unless the statement or description explicitly indicates the contrary. However, alternative embodiments of the present invention may be stated or described as consisting essentially of certain features, in which embodiment features of the embodiment that would materially alter the principle of operation or the characteristics of the embodiment are absent therefrom. Additional alternative embodiments of the invention may be stated or described as consisting of certain features, in which embodiment, or insubstantial variations thereof, only the features specifically stated or described are present.

Claims (17)

1. A process for preparing an ether of an aromatic acid, the ether being described by the structure of formula I

Wherein Ar is C₆-C₂₀A monocyclic or polycyclic aryl nucleus, R is a monovalent organic group, n and m are each independently nonzero values, and n + m is less than or equal to 8; the method comprises the following steps

(a) Reacting a halogenated aromatic acid as described in the structure of formula II

Wherein each X is independently Cl, Br or I, and Ar, n and m are as described above, with:

(i) containing the alcoholate RO^-M⁺(wherein M is Na or K), wherein the polar protic, polar aprotic, or alcoholic solvent is ROH or a solvent less acidic than ROH;

(ii) a copper (I) or copper (II) source; and

(iii) copper-coordinating diketone ligands as described by the structure of formula III

Wherein A is

R¹And R²Each independently selected from substituted and unsubstituted C₁-C₁₆N-alkyl, iso-alkyl and tertiary alkyl; and substituted and unsubstituted C₆-C₃₀Aryl and heteroaryl;

R³is selected from H; substituted and unsubstituted C₁-C₁₆N-alkyl, iso-alkyl and tertiary alkyl; substituted and unsubstituted C₆-C₃₀Aryl and heteroaryl; and a halogen;

R⁴、R⁵、R⁶and R⁷Each independently is H or substituted or unsubstituted C₁-C₁₆N-alkyl, iso-alkyl or tertiary alkyl; and n is 0 or 1;

to form a reaction mixture;

(b) heating the reaction mixture to form an m-basic salt of the product of step (a) as structurally described by formula IV;

(c) optionally, separating the m-basic salt of formula IV from the reaction mixture in which the m-basic salt of formula IV is formed; and

(d) contacting said m-basic salt of formula IV with an acid to thereby form an ether of an aromatic acid.

2. The process according to claim 1, wherein the halogenated aromatic acid is selected from the group consisting of 2-bromobenzoic acid, 2, 5-dibromobenzoic acid, 2-bromo-5-nitrobenzoic acid, 2-bromo-5-methylbenzoic acid, 2-chlorobenzoic acid, 2, 5-dichlorobenzoic acid, 2-chloro-3, 5-dinitrobenzoic acid, 2-chloro-5-methylbenzoic acid, 2-bromo-5-methoxybenzoic acid, 5-bromo-2-chlorobenzoic acid, 2, 3-dichlorobenzoic acid, 2-chloro-4-nitrobenzoic acid, 2, 5-dichloroterephthalic acid, 2-chloro-5-nitrobenzoic acid, 2, 5-dibromoterephthalic acid, and 2, 5-dichloroterephthalic acid.

3. The process of claim 1, wherein in step (a), the RO is present in a total of about n + m to n + m +1 standard equivalents^-M⁺(ii) said RO is added per equivalent amount of said halogenated aromatic acid^-M⁺Is added to the reaction mixture.

4. The method of claim 1, wherein the copper source comprises a Cu (I) salt, a Cu (II) salt, or a mixture thereof.

5. A process according to claim 4 wherein the copper source is selected from CuCl, CuBr, CuI, Cu₂SO₄、CuNO₃、CuCl₂、CuBr₂、CuI₂、CuSO₄、Cu(NO₃)₂And mixtures thereof.

6. The method according to claim 1, wherein the ligand comprises 2, 4-pentanedione, 2, 3-pentanedione, or 2, 2 ', 6, 6' -tetramethyl-3, 5-heptanedione (as shown in the following structure):

7. the method according to claim 1, further comprising the step of combining the copper source and the ligand prior to adding them to the reaction mixture.

8. A process according to claim 5 wherein the copper source comprises CuBr or CuBr₂。

9. The method according to claim 1, wherein the copper is provided in an amount of from about 0.1 mol% to about 5 mol% based on moles of halogenated aromatic acid.

10. The method according to claim 1, wherein the ligand is provided in an amount of about one to about two molar equivalents per mole of copper.

11. The method according to claim 1, wherein R is selected from C₁-C₁₂Alkyl, aryl, and groups described by the structure of the formula:

12. the method of claim 11, wherein R comprises C₁-C₄Alkyl or phenyl.

13. The process according to claim 1, wherein the alcoholic solvent comprises ROH.

14. The process according to claim 1, wherein the halogenated aromatic hydroxy acid comprises 2, 5-dibromoterephthalic acid or 2, 5-dichloroterephthalic acid; r comprises methyl, ethyl, isopropyl, isobutyl or phenyl; the alcohol solvent comprises ROH; the copper source comprises CuBr and CuBr₂Or CuBr and CuBr₂A mixture of (a); the copper source is provided in an amount of about 0.1 to about 5 mole percent based on moles of halogenated aromatic acid; the ligand comprises 2, 2 ', 6, 6' -tetramethyl-3, 5-heptanedione; and the ligand is provided in an amount of about one to about two molar equivalents per mole of copper.

15. The method according to claim 1, further comprising the step of subjecting the ether of an aromatic acid to a reaction to thereby produce a compound, monomer, oligomer or polymer.

16. The method according to claim 15, wherein the polymer produced comprises at least one member of the group consisting of: pyridobisimidazole, pyridobisthiazole, pyridobisoxazole, benzodiimidazole, benzodithiazole, and benzodioxazole moieties.

17. A method according to claim 16 wherein the polymer prepared comprises a pyridobisimidazole-2, 6-diyl (2, 5-dialkoxyphenylene) polymer.