Polythiol compound and method for producing same

Abstract

The present application relates to compounds which can be obtained independently from a) eugenol, b) gallic acid, c) an adduct of guaiacol and vanillin or d) resveratrol, each having the general formula VIA, VIB, VIC or VID: JPEG2025502655000045.jpg46168[where, R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18 Arylene or C7-C 18 an aralkylene group; and R 2 is H or methyl.

Description

[Technical field]

[0001] The present disclosure relates to novel polythiol compounds that can be derived from biorenewable resources. In particular, the present disclosure relates to polythiol compounds that can be derived from phenols, polyphenols, or phenolic acids that can be biorenewably sourced. [Background technology]

[0002] The chemical industry currently relies on historically inexpensive petroleum-based carbon feedstocks that generate a small number of platform chemicals for which highly efficient chemical conversion results in the production of a wide variety of chemical products. However, current approaches to producing these carbon-based chemicals are inherently unsustainable because they consume feedstocks that took millions of years to form. The creation of a sustainable chemical industry can only occur if the timescale of feedstock formation is equal to the timescale of its use to produce chemicals.

[0003] Given the essential need for carbon in chemical production, biomass, with its short formation time, must eventually become a feedstock for the chemical industry. Although biomass is a cheap feedstock, if the chemical industry is to transition to biomass feedstocks without significant cost disruption, efficient production paradigms must be developed that allow cheap and efficient processing of biomass.

[0004] Thiol-ene and thiol-epoxy polymers are attractive materials for coatings, adhesives and sealants due to their ease of preparation and low shrinkage and stress. Also, the use of the so-called "click reaction" in the synthesis of these materials offers an environmentally friendly technology, since it generates limited amounts of waste, consumes little energy, is a complete reaction method, and leads to the formation of homogeneous three-dimensional network structures in high yields without the formation of by-products. Moreover, such click reactions can be carried out in the absence of solvents and under air atmosphere, due to the limited water and oxygen sensitivity of the reactants, which is beneficial for many technological applications.

[0005] However, the problem is that thiol-, ene- and epoxy-containing compounds are generally derived from petrochemical sources. Certain authors have therefore attempted to derivatize compounds naturally occurring in biomass, in order to enable their use in, among other things, click reactions.

[0006] U.S. Patent Application Publication No. 2019 / 211139 (Robertson et al.) discloses a resin that includes (A) a naturally occurring aromatic compound that has been modified to contain at least one epoxidized hydroxy group and at least one epoxidized carboxylic acid group, and (B) a curing agent selected from an anhydride, an acid, an alcohol, a thiol, a phenol, or an amine, with the proviso that the aromatic compound is not an epoxidized form of gallic acid.

[0007] U.S. Patent Application Publication No. 2008 / 0021209 (East et al.) discloses a method for the synthesis of bisglycidyl ethers of anhydrosugars derived from renewable resources, including isosorbide, isomannide, and isoidide, which are said to be useful alternatives to bisphenol A diglycidyl ether.

[0008] WO 2010 / 136725 (Centre National de la Recherche Scientifique (CNRS) et al.) describes a method for producing epoxy resins from a mixture of epoxidized phenolic compounds, said epoxidized phenolic compounds being obtained by epoxidation of natural phenolic compounds selected from the group consisting of simple phenols, phenolic acids, coumarins, naphthoquinones, stilbenoids, flavonoids, isoflavonoids, anthocyanins, condensed tannins and hydrolyzable tannins.

[0009] US Patent No. 8,513,374 (Dasgupta) describes aryl-ene compounds which are derivatives of plant polyphenols and are selected from the group consisting of curcumin diallyl carbonate, tetrahydrocurcumin diallyl carbonate, resveratrol triallyl carbonate, mono-O-allyl curcumin, tetra-allyl curcumin, di-allyl tetrahydrocurcumin, tetra-allyl tetrahydrocurcumin and tri-O-allyl resveratrol. The utility of these aryl-functionalized compounds as monomers in the formation of polymers via thiol-ene chemistry is disclosed. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] US Patent Application Publication No. 2019 / 211139 [Patent Document 2] US Patent Application Publication No. 2008 / 0021209 [Patent Document 3] International Publication No. 2010 / 136725 [Patent Document 4] U.S. Pat. No. 8,513,374 Summary of the Invention [Problem to be solved by the invention]

[0011] These references do not teach or suggest thiol-functional compounds that may be derived from bio-renewable compounds. Thus, there is believed to be a need in the art to provide such thiol-functional compounds. [Means for solving the problem]

[0012] According to a first aspect of the invention, there is provided a compound of general formula VIA, VIB or VIC: [ka] [In the formula, R 1 is C1-C18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18 Arylene or C7-C 18 an aralkylene group; and R 2 is H or methyl] The present invention provides a polythiol compound having the formula:

[0013] With respect to the general formula above, R 1 is unsubstituted C1-C 12 alkylene group, more preferably an unsubstituted C1-C4 alkylene group, and R 2 is H or methyl.

[0014] Representative and important polythiols according to these general formulas are selected from VIAa, VIBa or VICa. [ka]

[0015] According to a further aspect of the invention, a compound of general formula VIA, VIB, VIC or VID: [ka] [In the formula, R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18 Arylene or C7-C 18 an aralkylene group; and R 2 is H or methyl] 1. A method for producing a compound having the formula: The method comprises treating a vehicle comprising a vehicle having the general formula IA, IB, IC or ID: [ka] providing a compound having the formula: moreover, a) reacting a compound of general formula IA, IB, IC or ID with a compound of general formula: X-(R 1 )-C(R 2 )=CH2(II) [wherein X is a halogen or an -OC(=O)OR° group; R° is a C1-C4 alkyl group; R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18 Arylene or C7-C 18 an aralkylene group; and R 2 is H or methyl] to give compounds of formula IIIA, IIIB, IIIC or IIID, respectively: [ka] forming a b) reacting said compound of formula IIIA, IIIB, IIIC or IIID with a compound of the general formula R 3 -C(=O)-SH (IV) [In the formula, R 3 is C1-C6 alkyl, C6-C 18 Aryl, C7-C 18 Alkylaryl or C7-C 18 aralkyl] to give thioester compounds of formula VA, VB, VC or VD, respectively: [ka] and forming c) deprotecting the thioester compound of formula VA, VB, VC or VD to form a polythiol compound of formula VIA, VIB, VIC or VID, respectively; The present invention provides a method comprising:

[0016] The compounds of formula IA, IB, IC and ID can be provided directly or can be derived from phenols, phenolic acids and polyphenols which can be bio-renewably sourced.

[0017] In this aspect of the disclosure, the primary aryl compound (II) is a primary aryl compound having R° C1-C2 alkyl; R 1 But unsubstituted C1-C 12 an alkylene group, preferably an unsubstituted C1-C4 alkylene group; and R 2 is preferably H or Me. In an important embodiment, the primary allyl compound (II) is selected from the group consisting of 3-chloro-1-propene, 3-bromoprop-1-ene, 3-iodoprop-1-ene, methyl prop-2-enyl carbonate, and ethyl prop-2-enyl carbonate.

[0018] With respect to step b) above, the reactant thiol acid (IV) is 3 C1-C4 alkyl, C6 aryl, C7-C 18 Alkylaryl or C7-C 18 It is preferably characterized as being aralkyl. It may be mentioned that it is particularly preferred that the thiol acid (IV) is selected from the group consisting of thioacetic acid, thiopropionic acid, thiobutyric acid, thioisobutyric acid, thiobenzoic acid, 2-methyl-thiobenzoic acid, 3-methyl-thiobenzoic acid, 4-methyl-thiobenzoic acid, 2,4-dimethyl-thiobenzoic acid and 3,5-dimethyl-thiobenzoic acid. Also, good results were obtained when either thioacetic acid or thiobenzoic acid was used as the reactant thiol acid (IV).

[0019] According to another aspect of the invention, the compound of formula VIB, VIC or VID [ka] [In the formula, R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18 Arylene or C7-C 18 an aralkylene group; and R 2 is H or methyl] 1. A method for producing a compound having the formula: The method comprises reacting a compound of general formula IB, IC or ID: [ka] and further comprising providing a compound having the formula: α) reacting a compound of formula IA, IB, IC or ID with a compound of formula VII: [ka] [In the formula, Y represents a halogen; R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18 Arylene or C7-C 18 is an aralkylene group; R 2 is H or methyl; and R 3 is C1-C6 alkyl, C6-C 18 Aryl, C7-C 18 Alkylaryl or C7-C 18 aralkyl] with a thiolate compound having the formula VB, VC or VD, respectively: [ka] forming a thioester compound of the formula: β) deprotecting the thioester compound of formula VA, VB, VC or VD to form a polythiol compound of formula VIA, VIB, VIC or VID, respectively; The present invention provides a method comprising:

[0020] With respect to the thiolate compound of formula VII, R 1 is unsubstituted C1-C 12 is an alkylene group; R 2 is H or Me; R 3 C1-C4 alkyl, C6 aryl, C7-C 18 Alkylaryl or C7-C 18 In an important embodiment, R is an aralkyl group. 1 is an unsubstituted C1-C4 alkylene group; R 2 is H or Me; and R 3 is C1-C4 alkyl.

[0021] The deprotection step of alternative process (c), β) above may be carried out reductively but is preferably carried out by acid- or base-catalyzed hydrolysis.

[0022] According to another further aspect of the present disclosure, there is provided the use of a polythiol compound having the general formula VIA, VIB or VIC as defined hereinabove and in the appended claims as a reactive component of a one-component (1K) or two-component (2K) curable composition.

[0023] The present disclosure also provides a) General formula VIA, VIB, VIC or VID: [ka] [In the formula, R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18Arylene or C7-C 18 an aralkylene group; and R 2 is H or methyl] At least one polythiol compound having the formula: b) at least one thiol-reactive compound, wherein the or each thiol-reactive compound has at least one functional group (F) selected from the group consisting of an epoxy group; an oxetane group; a cyclic carbonate group; a cyclic anhydride group; a 1-oxacycloalkan-2-one group; an ethylenically unsaturated group; an alkyne group; and an isocyanate group.

[0024] Component a) of the curable composition may in particular comprise at least one polythiol compound having the general formula VIA, VIB or VIC.

[0025] According to yet a further aspect of the present disclosure, a compound of general formula IIIC: [ka] [In the formula, R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18 Arylene or C7-C 18 an aralkylene group; and R 2 is H or methyl] The present invention provides a compound of the formula:

[0026] In the above formula IIIC, R 1 is unsubstituted C1-C 12 an alkylene group, preferably a C1-C4 alkylene group; and R 2 is preferably H or Me. In exemplary compounds, R 1 is methylene, R 2is H. The compound of formula IIIC is believed to be a key novel intermediate formed in the first process defined hereinbefore.

[0027] According to a final aspect of the invention, a compound of general formula VID: [ka] [In the formula, R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18 Arylene or C7-C 18 an aralkylene group; and R 2 is H or methyl (where R 2 If H, then R 1 does not become a methylene group. The present invention provides a compound of the formula:

[0028] When the general formula and conditions are met, R 1 is unsubstituted C1-C 12 alkylene group, more preferably an unsubstituted C1-C4 alkylene group; and R 2 is preferably H or methyl.

[0029] It will be appreciated that when compounds IA, IB, IC and ID are biorenewably sourced, the resulting compounds will have significant biocarbon content, with biocarbon content (%) being defined as 100 x (number of carbon atoms in biobased starting material (I) / number of carbon atoms in synthetic polythiol). The following achievable biocarbon contents can be mentioned: compound VIAa, 77%; compound VIBa, 37%; and compound VICa, 71%. [Brief description of the drawings]

[0030] [Figure 1] FIG. 2 is an illustration of step a) of the method of the first embodiment of the present disclosure. [Diagram 2]FIG. 2 is an illustration of step b) of the method of the first embodiment of the present disclosure. [Diagram 3] FIG. 2 is an illustration of step c) of the method of the first embodiment of the present disclosure. [Figure 4] FIG. 2 is an illustration of step α) of the method of the second embodiment of the present disclosure. [Diagram 5] FIG. 2 is an illustration of steps aa) and bb) of the method of the third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] (definition) As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0032] As used herein, the terms "comprising," "comprises," and "comprised of" are synonymous with "including," "includes," "containing," or "contains," and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or method steps.

[0033] As used herein, the term "consisting of" excludes any element, component, material or method step not specified. For completeness, the term "comprising" includes "consisting of".

[0034] When amounts, concentrations, dimensions, and other parameters are expressed in the form of ranges, preferred ranges, upper values, lower values, or preferred upper values ​​and limits, it is understood that any range obtained by combining any upper or preferred value with any lower limit or preferred value is also specifically disclosed, regardless of whether the resulting range is expressly stated in the context.

[0035] Furthermore, in accordance with standard understanding, weight ranges expressed as "from 0" specifically include 0 wt. %: the component defined by said range may or may not be present in the composition.

[0036] The terms "preferred," "preferably," "desirably," "in particular," and "particularly" are frequently used herein to refer to embodiments of the present disclosure that may provide particular benefits, under particular circumstances. However, the recitation of one or more preferred, preferred, desirable, or particular embodiments does not imply that other embodiments are not useful, and is not intended to exclude such other embodiments from the scope of the present disclosure.

[0037] As used throughout this application, the term "may" is used in a permissive rather than mandatory sense; it means having the possibility.

[0038] As used herein, room temperature (RT) is 23° C. plus or minus 2° C. As used herein, "ambient conditions" refers to the temperature and pressure surrounding the composition or an adhesive, sealant, coating or composite structure derived from said composition.

[0039] Molecular weights referred to herein (to describe the polymeric, oligomeric and polymeric components of the curable compositions) can be measured using gel permeation chromatography (GPC) using polystyrene calibration standards, such as performed in accordance with ASTM 3536.

[0040] The term "molar equivalent" is used according to its standard meaning and thus refers to the number of moles of a particular compound or functional group A relative to the number of moles of a particular compound or functional group B.

[0041] As used herein, the term "equivalent (eq.)," as is customary in chemical notation, relates to the relative numbers of reactive groups present in a reaction.

[0042] The term "equivalent weight" as used herein refers to the molecular weight divided by the number of associated functional groups. Thus, "epoxy equivalent weight" (EEW) means the weight (in grams) of a resin containing one equivalent of epoxide.

[0043] As used herein, the term "water" is intended to encompass tap water, spring water, purified water, deionized water, demineralized water and distilled water.

[0044] As used herein, "basicity" refers to the property of being a base rather than an acid. More specifically, according to the Lewis theory of acids and bases, a base is an electron pair donor. This definition includes, but is not limited to, Bronsted-Lowry bases, which function as proton acceptors.

[0045] As used herein, the term "one-component (1K) composition" refers to a composition in which the composition components are all mixed together during storage of the composition, but the properties of the composition, including viscosity, remain sufficiently consistent over the storage period that the composition can be successfully utilized at a later time.

[0046] A "two-component (2K) composition" is understood to be a composition in which the first component (A) and the second component (B) must be stored in separate containers due to their (high) reactivity. The two components are mixed only immediately before application and then react, typically without additional activation, forming bonds, thereby forming a polymer network. Here, a higher temperature can be applied to accelerate the crosslinking reaction.

[0047] Certain embodiments of the present disclosure describe dual cure compositions. As used herein, the term "dual cure composition" refers to a composition that cures upon exposure to two different cure conditions. For example, a dual cure composition may cure upon exposure to a combination of thermal energy and radiation. Thermal energy is intended to include radiant energy, such as infrared or microwave energy; and conductive thermal energy, such as that produced by a heated plate or oven. As used herein, the term "radiation" includes ionizing radiation, such as electron beam; and actinic radiation.

[0048] As used herein, the term "free radical initiator" refers to any chemical species that upon exposure to sufficient energy, for example in the form of light or heat, breaks down into two parts that are uncharged but each have at least one unpaired electron. Thus, thermal free radical initiators are liberated upon exposure to heat. Known thermal free radical initiators also include, but are not limited to, peroxide compounds, azo compounds, and persulfate compounds.

[0049] The term "photoinitiator" as used herein refers to a compound that can be activated by exposure to an energy-bearing activation beam, such as electromagnetic radiation. Specifically, "free radical photoinitiator" as used herein refers to a photoactive compound that generates free radicals, which can initiate polymerization or reactions by addition to C=C double bonds present in the composition.

[0050] The term "aprotic solvent" as used herein refers to a solvent that does not produce or accept protons. Conversely, a "protic solvent" is a solvent that can produce or accept protons. As used herein, a "polar solvent" refers to a solvent having a dielectric constant (ε) greater than 5 measured at 25°C, the term encompassing both aprotic and protic solvents. The determination of the dielectric constant (ε) is well known in the art and within the knowledge of the skilled artisan, and in such determination may refer to the use of the measured voltage across a parallel plate capacitor.

[0051] As used herein, the term "epoxide" refers to a compound characterized by the presence of at least one cyclic ether group, i.e., an ether oxygen atom is bonded to two adjacent carbon atoms, thereby forming a cyclic structure. The term is intended to encompass monoepoxide compounds, polyepoxide compounds (having two or more epoxy groups), and epoxy-terminated prepolymers. The term "monoepoxide compound" is meant to refer to an epoxide compound having one epoxy group. The term "polyepoxide compound" is meant to refer to an epoxide compound having at least two epoxy groups. The term "diepoxide compound" is meant to refer to an epoxide compound having two epoxy groups.

[0052] The epoxides may be unsubstituted or inertly substituted. Exemplary inert substituents include chlorine, bromine, fluorine and phenyl.

[0053] As used herein, "(meth)acrylic" is an abbreviation for "acrylic" and / or "methacrylic". Thus, the term "(meth)acrylate" collectively refers to acrylate and methacrylate. Similarly, "allyl" and "methallyl" are referred to herein in summary form as "(meth)allyl".

[0054] As used herein, "C1-C nAn "alkyl" group refers to a monovalent group containing 1 to n carbon atoms, i.e., an alkane group, and includes linear and branched organic groups. Thus, "C1-C 18 An "alkyl" group refers to a monovalent group, i.e., an alkane group, containing 1 to 18 carbon atoms, and includes straight-chain and branched organic groups. Examples of alkyl groups include, but are not limited to, methyl; ethyl; propyl; isopropyl; n-butyl; isobutyl; sec-butyl; tert-butyl; n-pentyl; n-hexyl; n-heptyl; and 2-ethylhexyl. In the present invention, such alkyl groups may be unsubstituted or substituted with one or more halogens. If applicable to a given moiety (R), the tolerance for one or more non-halogen substituents in an alkyl group is noted herein.

[0055] As used herein, "C1-C n The term "hydroxyalkyl" refers to a HO-(alkyl) group having 1 to n carbon atoms, where the point of attachment of the substituent is through the oxygen atom and the alkyl group is as defined above.

[0056] "Alkoxy group" refers to a monovalent group represented by -OA, where A is an alkyl group, non-limiting examples of which are methoxy, ethoxy, and iso-propyloxy. 12 "Alkoxyalkyl," as used herein, refers to an alkyl group having an alkoxy substituent, as defined above, where the moiety (alkyl-O-alkyl) contains a total of 1 to 12 carbon atoms; such groups include methoxymethyl (-CHOCH), 2-methoxyethyl (-CHCHOCH), and 2-ethoxyethyl.

[0057] As used herein, the term "C1-C8 alkanol" refers to a compound of general formula ROH, where R is an alkyl group having 1 to 8 carbon atoms as defined above. It should be mentioned that in the described process steps, C1-C4 alkanols, more specifically methanol or ethanol, are preferred.

[0058] As used herein, "C1-C n The term "alkylene" is defined as a saturated divalent hydrocarbon group having 1 to n carbon atoms. In general, in this disclosure, such alkylene groups may be unsubstituted or substituted with one or more halogens or one or more hydroxyls. If applicable to a given moiety (R), the tolerance for one or more non-halogen substituents in an alkylene group is noted herein.

[0059] "C2-C 18 The term "oxyalkylene group" means two or more alkylene groups linked by one or more oxygen atoms in an ether bond, said groups having a total of 2 to 19 carbon exams. Examples include mono-ether groups represented by -alkylene-O-alkylene- and di-ether groups represented by alkylene-O-alkylene-O-alkylene-, the term alkylene having the above meaning.

[0060] "C2-C 18 The term "thioalkylene group" means two or more alkylene groups linked by one or more sulfur atoms in a thioether bond, said groups having a total of 2 to 19 carbon exams. Examples include monothioether groups represented by -alkylene-S-alkylene-, and diether groups represented by alkylene-S-alkylene-S-alkylene-, the term alkylene having the above meaning.

[0061] "C3-C 30The term "cycloalkyl" is understood to mean a saturated monocyclic or polycyclic hydrocarbon group having 3 to 30 carbon atoms. In the present invention, such cycloalkyl groups may be unsubstituted or substituted with one or more halogens. If applicable to a given moiety (R), the tolerance for one or more non-halogen substituents in a cycloalkyl group is mentioned herein. Examples of cycloalkyl groups include: cyclopropyl; cyclobutyl; cyclopentyl; cyclohexyl; cycloheptyl; cyclooctyl; adamantane; and norbornane.

[0062] As used herein, "C3-C 30 The term "hydroxycycloalkyl" refers to a HO-(cycloalkyl) group having 3 to 30 carbon atoms, where the point of attachment of the substituent is through the oxygen atom and the cycloalkyl group is as defined above.

[0063] As used herein, "C-C alkyl" used alone or as part of a larger moiety such as an "aralkyl group" refers to a C-C alkyl group. 18 "Aryl" groups refer to monocyclic, bicyclic and tricyclic ring systems in which the monocyclic ring is aromatic or at least one of the rings of the bicyclic or tricyclic ring is aromatic. Bicyclic and tricyclic ring systems include benzo-fused 2-3 membered carbocyclic rings. In the present invention, such aryl groups may be unsubstituted or substituted with one or more halogens. If applicable to a given moiety (R), tolerance for one or more non-halogen substituents in an aryl group is mentioned herein. Exemplary aryl groups include: phenyl; indenyl; naphthalenyl, tetrahydronaphthyl, tetrahydroindenyl; tetrahydroanthracenyl; and anthracenyl. It may also be mentioned that the phenyl group is preferred.

[0064] "C6-C 18 The term "arylene" refers to a divalent hydrocarbon radical having 6 to 18 carbon atoms derived from an aryl group as defined above. An exemplary arylene group is phenylene (-C6H4-).

[0065] As used herein, "C2-C 20 "Alkenyl" refers to a hydrocarbyl group having 2 to 20 carbon atoms and at least one unit of ethylenic unsaturation. Alkenyl groups may be linear, branched or cyclic and may be optionally substituted with one or more halogens. If applicable to a given moiety (R), the tolerance for one or more non-halogen substituents in an alkenyl group is noted herein. The term "alkenyl" also encompasses groups having "cis" and "trans" configurations, or alternatively, "E" and "Z" configurations, as would be understood by one of ordinary skill in the art. The C2-C 20 Examples of alkenyl groups are -CH=CH2;-CH=CHCH3;-CH2CH=CH2;-C(=CH2)(CH3);-CH=CHCH2CH3;-CH2CH=CHCH3;-CH2CH2CH=CH2;-CH=C(CH3)2; -CH2C(=CH2)(CH3);-C(=CH2)CH2CH3;-C(CH3)=CHCH3;-C(CH3)CH=CH2;-CH=CHCH2CH2CH3;-CH2CH=CHCH2CH3;-CH2CH2CH=CHCH3 ;-CH2CH2CH2CH=CH2;-C(=CH2)CH2CH2CH3;-C(CH3)=CHCH2CH3;-CH(CH3)CH=CHCH;-CH(CH3)CH=CHCH;-CH(CH3)CH2CH=CH2;-CH2CH=C(CH3)2;1-cyclopent-1-enyl;1-cyclopent-2-enyl;1-cyclopent-3-enyl;1-cyclohex-1-enyl;1-cyclohex-2-enyl; and, 1-cyclohexyl-3-enyl.

[0066] As used herein, "alkylaryl" refers to an alkyl-substituted aryl group, both of which are defined above. Additionally, as used herein, "aralkyl" refers to an alkyl group substituted with an aryl group as defined above. As used herein, "C1-C nThe term "aralkylene" is defined as a saturated divalent hydrocarbon radical having 1 to n carbon atoms, wherein an alkylene group, as defined above, is substituted with an aryl group, as defined above.

[0067] The term "hetero" as used herein refers to groups or moieties that contain one or more heteroatoms, such as N, O, Si, and S. Thus, for example, "heterocyclic" refers to cyclic groups having, for example, N, O, Si, or S as part of the ring structure. "Heteroalkyl," "heterocycloalkyl," and "heteroaryl" moieties are alkyl, cycloalkyl, and aryl groups, as defined above, that contain N, O, Si, or S as part of their structure, respectively.

[0068] With respect to compositions and process conditions that may be defined, the term "substantially free" is intended to mean that a compound, element, ion, or other similar component is not intentionally added to the composition or reaction mixture and is present, at most, in trace amounts that would not (detrimentally) affect the desired properties of the composition or the progress of the reaction. An exemplary trace amount is less than 1000 ppm by weight of the composition. The term "substantially free" encompasses embodiments in which a particular compound, element, ion, or other similar component is completely absent from the composition or reaction mixture or is absent in any amount measurable by techniques commonly used in the art.

[0069] The term "anhydrous" as used herein is equivalent to the term "substantially free of water." Water is not intentionally added to a given composition and, at most, is present in trace amounts that will not (detrimentally) affect the desired properties of the composition.

[0070] The initial reactants of the disclosed method can be described as follows:

[0071] Compound IA: Eugenol (2-methoxy-4-(prop-2-en-1-yl)phenol) [ka] Eugenol is an allyl-chain substituted guaiacol. It occurs naturally in celery, dill, ginger, lemon balm, vanilla, wood avens and mugwort, among others, but is traditionally extracted from certain essential oils derived from cloves, nutmeg, cinnamon, basil and bay leaves. Eugenol can also be derived from the constituent guaiacyl and syringyl structural units present in lignin.

[0072] Compound IB: Gallic acid (3,4,5-trihydroxybenzoic acid) [ka] This compound is classified as a phenolic acid and is found naturally in gall nuts, sumac, witch hazel, tea leaves and oak bark. It is also found in many land plants, such as the parasitic plant Cynomorium coccineum and the aquatic plant Myriophyllum spicatum and the blue-green algae Microcystis aeruginosa.

[0073] Compound IC: Tris(3-methoxy-4-hydroxyphenyl)methane. Without intending to limit the invention, this compound may be synthesized by the reaction of guaiacol (2-methoxyphenol) with vanillin (4-hydroxy-3-methoxybenzaldehyde). [ka]

[0074] Guaiacol (2-methoxyphenol) consists of a phenol with a methoxy substituent at the ortho position. Although biosynthesis of guaiacol by Leptoglossus phyllopus has been reported, guaiacol is more conventionally derived from the flowering plant guaiacum, from celery seeds, tobacco leaves, orange leaves and lemon peel, or as the major aromatic monomer of depolymerized lignin. Wood distillation products, especially hardwood dried distillate oils, are important sources of guaiacol.

[0075] Vanillin (4-hydroxy-3-methoxybenzaldehyde) is the major chemical compound in the extract of the seed pods of the orchid Vanilla planifolia. However, other sustainable sources of vanillin are known. It can be obtained, for example, from guaiacol sourced by the methods described above, or may itself be derived from thermal and / or electrochemical lignin depolymerization methods.

[0076] The described reaction of vanillin with guaiacol should be carried out in the presence of a catalyst, with protic acids and / or Lewis acids being suitable in this regard. Exemplary protic acids include hydrochloric acid, sulfuric acid, phosphoric acid, perchloric acid, oxalic acid, trifluoroacetic acid and organic sulfonic acids such as methanesulfonic acid and p-toluenesulfonic acid (PTSA). Exemplary Lewis acids include boron trifluoride, ferric chloride, zinc chloride, zinc bromide, stannic chloride and titanium chloride. It is noted that good results were obtained when the reaction was carried out with either concentrated sulfuric acid or p-toluenesulfonic acid-mediated zinc chloride.

[0077] Exemplary solvents for this reaction include, but are not limited to, polar aprotic solvents including C1-C8 alkanols, such as ethanol; acetonitrile; N,N-di(C1-C4) alkyl acyl amides, such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMAc); hexamethylphosphoramide; N-methylpyrrolidone; pyridine; esters, such as (C1-C8) alkyl acetates, ethoxydiglycol acetate, dimethyl glutarate, dimethyl maleate, dimethyl methacrylate ... ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF) and 1,2-dimethoxyethane; 1,3-dioxolane; dimethylsulfoxide (DMSO); and dichloromethane (DCM).

[0078] The process can be carried out at temperatures of about 0 to 100° C., with temperatures of 20 to 80° C. being preferred. The solvent used, the catalyst used and the temperature of the reaction will determine the reaction time: durations of 5 to 200 hours may be required.

[0079] The progress of the above reaction is as follows: 1 The reaction can be monitored by known techniques, which may include H NMR, Fourier transform infrared spectroscopy, ultra-performance liquid chromatography (UPLC) or thin layer chromatography (TLC). Once the reaction is complete, the resulting mixture is filtered to remove solids; the solvent is removed from the filtrate to obtain the crude product (IC).

[0080] The crude product (IC) may be used in subsequent steps of the process or the related compounds may be purified using methods known in the art, including but not limited to solvent extraction, filtration and chromatography.

[0081] For completeness, an exemplary synthesis method for the compound of formula IC is provided in Zhao S. et al. Renewable Epoxy Thermosets from Fully Lignin-Derived Triphenols, ACS Sustainable Chem. Eng. 6:7600-7608 (2018).

[0082] Compound ID: Resveratrol (3,5,4'-trihydroxy-trans-stilbene) [ka] Resveratol is a type of stilbenoid, a natural phenol, and a phytoalexin produced by some plants in response to wounding or when the plant is under attack by pathogens such as bacteria or fungi. Important sources of resveratrol from which the compound can be extracted include grapes, blueberries, raspberries, mulberries and peanut skins.

[0083] In the following description, reference is made to the accompanying drawings.

[0084] The individual steps of the above defined methods are described in more detail herein below. Both chemical structures and chemical names are used to refer to compounds, and if there is an ambiguity between the structure and the name, the structure predominates.

[0085] First Method Embodiment This method embodiment is characterized in that a compound of formula VI is formed from a compound of formula I via an allyl-functional intermediate (III). In the description of this embodiment below, when reference is made to formulae I, III, V and VI, this is intended to denote IA-ID, IIIA-IIID, VA-VD and VIA-VID, respectively.

[0086] Step a) Allylation This step of the described method shown in Figure 1 provides for the reaction of a compound of formula I with a primary allyl compound (II) in the presence of at least one base. The primary allyl compound (II) corresponds to the allyl substituent introduced into the allyl ether product (III) of this step. As shown in the reaction scheme above, the primary allyl compound (II) has the general formula: X-(R 1 )-C(R 2 )=CH2 [wherein X is a halogen or an -OC(=O)OR° group; R° is a C1-C4 alkyl group; R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene group, C6-C 18 Arylene or C7-C 18 an aralkylene group; and R 2 is H or methyl] has.

[0087] In most cases, allyl chloride (X=Cl) is preferred due to its lower cost, but allyl bromide and allyl iodide may be more reactive, especially in the case of higher molecular weight allyl compounds. In the preferred first description, R° is C1-C4 alkyl; R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group or C2-C 18 R is a thioalkylene group; 2 is preferably H or Me. In particular, R° is C1-C2 alkyl; R 1 is unsubstituted C1-C 12 is an alkylene group; R 2 is preferably H or Me. In an important embodiment: R 1 is an unsubstituted C1-C4 alkylene group; R 2 is H or Me.

[0088] Exemplary primary allyl halides according to formula II include: 3-chloro-1-propene (allyl chloride); 3-bromoprop-1-ene (allyl bromide); 3-iodoprop-1-ene (allyl iodide); 3-chloro-2-methyl-1-propene (methallyl chloride); 3-bromo-2-methyl-1-propene (methallyl bromide); 3-iodo-2-methyl-1-propene (methallyl iodide); 4-chloro-but-1-ene; 4-bromo-but-1-ene; 4-iodo-but-1-ene; 5-chloropent-1-ene; 5-bromopent-1-ene; 1-ene; 5-iodopen-1-ene; 6-chlorohex-1-ene; 6-bromohex-1-ene; 6-iodohex-1-ene; 7-chlorohept-1-ene; 7-bromohept-1-ene; 7-iodohept-1-ene; 8-chlorooct-1-ene; 8-bromooct-1-ene; 8-iodooct-1-ene; 10-chlorodec-1-ene; 10-bromodec-1-ene; 10-iododec-1-ene; 12-chlorododec-1-ene; 12-bromododec-1-ene; and 12-iododec-1-ene. Of the primary allyl halides, the use of 3-chloro-1-propene (allyl chloride); 3-bromoprop-1-ene (allyl bromide); and 3-iodoprop-1-ene (allyl iodide) can be said to be preferred, with the use of 3-bromoprop-1-ene being recognized as being particularly preferred.

[0089] Exemplary further reactants according to formula II include: methyl prop-2-enyl carbonate; ethyl prop-2-enyl carbonate; prop-2-enyl propyl carbonate; n-butyl prop-2-enyl carbonate; methyl 2-methylprop-2-enyl carbonate; and ethyl 2-methylprop-2-enyl carbonate. Of these reactants, it can be said that the use of methyl prop-2-enyl carbonate or ethyl prop-2-enyl carbonate is preferred.

[0090] It is intended that each hydroxyl group in the compound of formula I is subjected to allylation, therefore the primary allyl compound (II) should be present in at least a stoichiometric equivalent amount relative to the moles of said hydroxyl groups. The reaction mixture may in particular contain said primary allyl compound (II) in 1-2 molar equivalents relative to the moles of hydroxyl groups of formula I. Preferably, the allyl compound (II) is reacted in 1.2-1.8 molar equivalents relative to the moles of hydroxyl groups of formula I.

[0091] The base present should be present in at least the stoichiometric amount from the reaction, since it reacts with the halogen acid liberated during the reaction. However, the reaction can be operated in the presence of an excess of base, and thus the base can be present in the reaction mixture in an amount of 1 to 5 molar equivalents relative to the amount of compound (I). It is preferred that the base is present in an amount of 1.5 to 3 molar equivalents or 1.5 to 2.5 molar equivalents relative to the amount of compound (I).

[0092] Without intending to limit the invention, the base should desirably consist of at least one compound selected from alkali metals, alkaline earth metals, alkali metal (C1-C4) alkoxides, alkaline earth metal (C1-C4) alkoxides, alkali metal carbonates, alkaline earth metal carbonates, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal hydrides and alkaline earth metal hydrides. The use of at least one of potassium carbonate, sodium carbonate and calcium carbonate may be preferred.

[0093] In certain embodiments, the addition of neutral alkali metal salts to the reaction mixture can have a positive effect on the yield of the allylation product. Exemplary alkali metal salts include: sulfates, sulfites, sulfides, halides, nitrates, nitrites, cyanides, borates, phosphates, monohydrogen phosphates, dihydrogen phosphates, phosphites, acid phosphites, and carboxylates, such as acetates, formates, propionates, oxalates, tartrates, succinates, maleates, and adipates.

[0094] A small amount of neutral alkali metal salt, for example 0.01-0.05 mole per mole of compound (I), has a yield-improving effect, but the amount of said neutral salt should not exceed the amount of the basic catalyst contained in the reaction mixture.

[0095] This step is further carried out in the presence of an inert aprotic solvent. Examples of suitable aprotic solvents that can be used alone or in combination include pentane, hexane, heptane, cyclopentane, cyclohexane, cycloheptane, dimethyl ether, chloroform, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, 2-propylbenzene (cumene), 2-isopropyltoluene (o-cymol), 3-isopropyltoluene (m-cymol), 4-isopropyltoluene (p-cymol), 1,3,5-trimethylbenzene (mesitylene), acetonitrile, N,N-di(C1-C4) alkyl acylamides such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMF). DMAc); hexamethylphosphoramide; N-methylpyrrolidone; pyridine; esters such as (C1-C8) alkyl acetates, ethoxydiglycol acetate, dimethyl glutarate, dimethyl maleate, dipropyl oxalate, ethyl lactate, benzyl benzoate, butyl octyl benzoate and ethylhexyl benzoate, ketones such as acetone, ethyl ketone, methyl ethyl ketone (2-butanone), and methyl isobutyl ketone; ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF) and 1,2-dimethoxyethane; 1,3-dioxolane; dimethyl sulfoxide (DMSO); and dichloromethane (DCM).

[0096] Although not critical, it is preferred that the reaction in this step be carried out under anhydrous conditions. If necessary, exposure to atmospheric moisture can be avoided by providing an inert, dry gas blanket to the reaction vessel. Dry nitrogen, helium and argon can be used as blanket gases, but care should be taken when using common nitrogen gas as a blanket, as such nitrogen may not be sufficiently dry due to its sensitivity to moisture entrainment; nitrogen may require an additional drying step before use here.

[0097] The reaction does not have to be carried out under reflux conditions, but it is preferred to do so. If reflux conditions are not used, carrying out the reaction at room temperature is not practically precluded, but the use of elevated temperatures, for example at least 50°C or at least 75°C, can facilitate the reaction. However, for exothermic reactions, some cooling may be required as the reaction proceeds.

[0098] The process pressure is not critical: the reaction can therefore be carried out at subatmospheric, atmospheric or superatmospheric pressure, although atmospheric pressure or slightly higher is preferred. In this connection, reference can be made to pressures of 50 to 200 kPa, for example 100 to 200 kPa.

[0099] The progress of the above reaction is as follows: 1 The reaction can be monitored by known techniques, which may include H NMR, Fourier transform infrared spectroscopy, ultra performance liquid chromatography (UPLC) or thin layer chromatography (TLC). Once the reaction is complete, the resulting mixture is filtered to remove solids; the solvent is removed from the filtrate to obtain the crude product.

[0100] The crude product may be used in subsequent steps of the process or the related compounds may be purified using methods known in the art, including but not limited to solvent extraction, filtration and chromatography.

[0101] Step b) Thiol-ene reaction In this step, shown in Figure 2, the allyl-functional compound (III) of step a) is reacted with a thiol acid (IV). The reactant thiol acid (IV) has the general formula: R 3 -C(=O)-SH (IV) [In the formula, R 3 is C1-C6 alkyl, C6-C 18 Aryl, C7-C 18 Alkylaryl or C7-C 18 aralkyl] Preferably, R 3 C1-C4 alkyl, C6 aryl, C7-C 18 Alkylaryl or C7-C 18 It is aralkyl.

[0102] Exemplary thiol acids include: thioacetic acid, thiopropionic acid, thiobutyric acid, thioisobutyric acid, thiocinnamic acid (3-phenylprop-2-enethio S-acid), thiobenzoic acid, 2-methyl-thiobenzoic acid, 3-methyl-thiobenzoic acid, 4-methyl-thiobenzoic acid, 2,4-dimethyl-thiobenzoic acid, and 3,5-dimethyl-thiobenzoic acid.It may be mentioned that the use of thioacetic acid or thiobenzoic acid is particularly preferred.

[0103] If a thiol-ene is intended to be generated at each allyl group, the thiol acid (IV) should be present in the reaction mixture in at least a stoichiometric equivalent amount relative to the moles of said allyl groups. The reaction mixture may, in this example, contain said thiol acid (IV) in a molar equivalent amount of 1 to 2 moles relative to said allyl groups. Preferably, the amount of thiol acid (IV) is in the range of 1.2 to 1.8 moles per mole of allyl groups.

[0104] When the reactants contain more than one allyl group, partial conversion of these groups can occur by using a substoichiometric amount of thiolic acid (IV) relative to the total number of moles of said allyl groups.

[0105] Those skilled in the art will recognize that the reaction of thiol group with -ene group may occur under exposure to actinic radiation, and therefore catalyst or accelerator may not be strictly required in this step of the method.However, this does not preclude the use of Michael addition catalyst in this step, which herein refers to a compound that can promote the Michael addition reaction between thiol acid and the compound of formula III having terminal C=C unsaturation.Michael addition catalyst can be used in an amount of 0-5% by weight, for example 0.05-2% by weight, based on the weight of said thiol acid.

[0106] Traditionally, Michael addition catalysts include amine catalysts, base catalysts and organometallic catalysts, which can be used alone or in combination. Exemplary amine catalysts include: proline; triazabicyclodecene (TBD); diazabicycloundecene (DBU); hexahydromethylpyrimidopyridine (MTBD); diazabicyclononane (DBN); tetramethylguanidine (TMG); and triethylenediamine (TED, 1,4-diazabicyclo[2.2.2]octane). Examples of base catalysts include: sodium methoxide; sodium ethoxide; potassium t-butoxide; potassium hydroxide; sodium hydroxide; sodium metal; lithium diisopropylamide (LDA); and butyl lithium. Exemplary organometallic catalysts include: ruthenium catalysts, such as (cyclooctadiene)(cyclooctatriene)ruthenium and ruthenium hydride; iron catalysts, such as iron(III) chloride, iron acetylacetonate; nickel catalysts, such as nickel acetylacetonate, nickel acetate, nickel salicylaldehyde; copper catalysts; palladium catalysts; scandium catalysts; lanthanum catalysts; ytterbium catalysts; and tin catalysts.

[0107] The thiol-ene reactions can be carried out under Michael addition catalysis, but these reactions can also be initiated by free radical generating thermal initiators or free radical photoinitiators. In this embodiment, the reaction mixture of this step can contain 0.1 to 1 wt. %, for example 0.1 to 0.5 wt. %, of at least one free radical initiator based on the weight of the thiol acid.

[0108] Typically, free radical photoinitiators are divided into those that form radicals by cleavage, known as "Norrish type I", and those that form radicals by hydrogen abstraction, known as "Norrish type II". Norrish type II photoinitiators require a hydrogen donor to act as a source of free radicals: since initiation is based on a bimolecular reaction, Norrrish type II photoinitiators are generally slower than Norrish type I photoinitiators, which are based on the unimolecular formation of radicals. On the other hand, Norrish type II photoinitiators have better light absorption properties in the near-UV spectral region. A person skilled in the art should be able to select a suitable free radical photoinitiator based on the radiation used and the sensitivity of the photoinitiator at that wavelength.

[0109] Preferred free radical photoinitiators are those selected from the group consisting of benzoylphosphine oxides, aryl ketones, benzophenones, hydroxylated ketones, 1-hydroxyphenyl ketones, ketals, and metallocenes. For the sake of completeness, combinations of two or more of these photoinitiators are not excluded in the present invention.

[0110] Particularly preferred free radical photoinitiators are benzoin dimethyl ether; 1-hydroxycyclohexyl phenyl ketone; benzophenone; 4-chlorobenzophenone; 4-methylbenzophenone; 4-phenylbenzophenone; 4,4'-bis(diethylamino)benzophenone; 4,4'-bis(N,N'-dimethylamino)benzophenone (Michler's ketone); isopropylthioxanthone; 2-hydroxy-2-methylpropiophenone (Daracur 1173); 2-methyl-4-(methylthio)-2-morpholinopropiophenone; methyl phenylglyoxylate; methyl 2-benzoylbenzoate; 2-ethylhexyl 4-(dimethylamino)benzoate; ethyl 4-(N,N-dimethylamino)benzoate; phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide; and ethylphenyl(2,4,6-trimethylbenzoyl)phosphinate. Again, certainly not excluded are combinations of two or more of these photoinitiators.

[0111] If the reaction mixture of step b) includes a free radical photoinitiator, irradiation of the reaction mixture generates active species from the photoinitiator that start the reaction. Once that species is generated, the chemistry follows the same rules of thermodynamics as any chemical reaction, and the reaction rate can be accelerated by heat.

[0112] The energy source used to initiate the reaction in this embodiment of step b) emits at least one of ultraviolet (UV), infrared (IR), visible light, x-rays, gamma rays, or electron beam (e-beam). The reaction can typically be activated in less than 2 minutes, generally 0.1 to 100 seconds, for example 3 to 12 seconds, when irradiated using commercially available curing equipment.

[0113] The ultraviolet light to be irradiated usually has a wavelength of 150 to 600 nm, preferably 200 to 450 nm. Useful sources of UV light include, for example, ultra-high pressure mercury lamps, high pressure mercury lamps, medium pressure mercury lamps, low intensity fluorescent lamps, metal halide lamps, microwave-driven lamps, xenon lamps, UV-LED lamps, and laser beam sources such as excimer lasers and argon-ion lasers.

[0114] When an electron beam is utilized to initiate the reaction, standard parameters for the operating device are: accelerating voltage of 0.1-100 keV; -3 The vacuum may be between 0.0001 and 1 Pa; the electron current between 0.0001 and 1 ampere; and the power output between 0.1 watts and 1 kilowatt.

[0115] The amount of radiation required to sufficiently initiate a reaction depends on a variety of factors, including the angle of exposure to the radiation and the volume of the reaction mixture. However, generally, it ranges from 5 to 5,000 mJ / cm. 2 can be cited as being typical, with doses of 50-500 mJ / cm 2 , for example, 50 to 200 mJ / cm 2 can be considered to be highly effective.

[0116] As will be appreciated by those skilled in the art, photosensitizers can be incorporated into the reaction mixture to improve the efficiency with which the photoinitiator uses the energy delivered. The term "photosensitizer" is used in accordance with its standard meaning to describe any substance that increases the rate of photoinitiated polymerization or shifts the wavelength at which polymerization occurs. Photosensitizers should be used in amounts of 0-25% by weight, based on the weight of the free radical photoinitiator.

[0117] Instead of using a free radical photoinitiator, a radical-generating thermal initiator may be used in this step. Organic peroxides represent one exemplary class, and such organic peroxides may be selected from, for example, cyclic peroxides, diacyl peroxides, dialkyl peroxides, hydroperoxides, peroxycarbonates, peroxydicarbonates, peroxyesters, and peroxyketals.

[0118] Certain peroxides, such as dialkyl peroxides, have been disclosed as useful initiators, inter alia, in U.S. Patent No. 3,419,512 (Lees) and U.S. Patent No. 3,479,246 (Stapleton), and may indeed have utility herein, but hydroperoxides represent a preferred class of initiators. Additionally, while hydrogen peroxide itself may be used, the most desirable polymerization initiators are organic hydroperoxides. For completeness, the definition of hydroperoxide includes materials such as organic peroxides or organic peresters that decompose or hydrolyze in situ to form organic hydroperoxides: examples of such peroxides and peresters are cyclohexyl and hydroxycyclohexyl peroxides and t-butyl perbenzoate, respectively.

[0119] In one embodiment of the invention, the radical-generating thermal initiator has the formula: R p OOH [In the formula, R p is an aliphatic or aromatic group containing up to 18 carbon atoms, Preferably, R p is C1-C 12 Alkyl, C6-C 18 Aryl or C7-C 18 an aralkyl group. The composition may comprise or consist of at least one hydroperoxide compound represented by:

[0120] Exemplary peroxide initiators which may be used alone or in combination include cumene hydroperoxide (CHP); paramenthane hydroperoxide; t-butyl hydroperoxide (TBH); t-butyl perbenzoate; t-butyl peroxypivalate; di-t-butyl peroxide; t-butyl peroxyacetate; t-butyl peroxy-2-hexanoate; t-amyl hydroperoxide; 1,2,3,4-tetramethylbutyl hydroperoxide; benzoyl peroxide; dibenzoyl peroxide. butyl 4,4-bis(t-butylperoxy)valerate; p-chlorobenzoyl peroxide; t-butylcumyl peroxide; di-t-butyl peroxide; dicumyl peroxide; 2,5-dimethyl-2,5-di-t-butylperoxyhexane; 2,5-dimethyl-2,5-di-t-butyl-peroxyhex-3-yne; and 4-methyl-2,2-di-t-butylperoxypentane.

[0121] Although not intended to limit the disclosure, a further exemplary class of radical-generating thermal initiators suitable for use in this reaction step are azo polymerization initiators selected from, for example, azonitriles; azoesters; azoamides; azoamidines; azoimidazolines; and macroazo initiators.

[0122] Representative examples of suitable azo polymerization initiators include 2,2'-azobis(2-methylbutyronitrile); 2,2'-azobis(isobutyronitrile) (AIBN); 2,2'-azobis(2,4-dimethylvaleronitrile); 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile); 1,1'-azobis(cyclohexane-1-carbonitrile); 4,4'-azobis(4-cyanovaleric acid); dimethyl 2,2'-azobis(2-methylpropionate); 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide]; 2,2'-azobis(N-butyl-2-methylpropionamide); 2,2'-azobis[2 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] tetrahydrate; 4,4-azobis(4-cyanovaleric acid), alpha,omega-bis(3-aminopropyl)polydimethylsiloxane polymer (VPS-1001, manufactured by Wako Pure Chemical Industries, Ltd.); and 4,4'-azobis(4-cyanopentanoic acid)·polyethylene glycol polymer (VPE-0201, manufactured by Wako Pure Chemical Industries, Ltd.).

[0123] Redox free radical initiators are combinations of oxidizing and reducing agents and may also be useful in thiol-ene based step b). Suitable oxidizing agents may be selected from the group consisting of cyclic peroxides, diacyl peroxides, dialkyl peroxides, hydroperoxides, peroxycarbonates, peroxydicarbonates, peroxyesters and peroxyketals. The corresponding reducing agents may be selected from the group consisting of alkali metal sulfites; alkali metal hydrogen sulfites; alkali metal metabisulfites; formaldehyde sulfoxylates; alkali metal salts of aliphatic sulfinic acids; alkali metal hydrogen sulfides; salts of polyvalent metals, in particular Co(II) and Fe(II) salts, such as iron(II) sulfate, ammonium iron(II) sulfate or iron(II) phosphate; dihydroxymaleic acid; benzoin; ascorbic acid; and reducing sugars, such as sorbose, glucose, fructose and / or dihydroxyacetone.

[0124] Step b) may be carried out at temperatures of 5 to 150° C., with temperatures in the range of 20 to 100° C. being more typical. Complete reaction may be achieved in as little as one hour, although at lower reaction temperatures as long as 24 hours may be required. Because the reaction is heterogeneous, stirring throughout the course of the reaction is important to maintain good physical contact between the reactants and improve the reaction rate. Any means of stirring may be used.

[0125] The process pressure of step b) is not critical: the reaction can therefore be carried out at subatmospheric, atmospheric or superatmospheric pressure, although atmospheric pressure or slightly higher pressures are preferred. In this connection, mention may be made of pressures between 50 and 200 kPa, for example between 100 and 200 kPa.

[0126] The progress of the above reaction is as follows: 1 The reaction can be monitored by known techniques, including H NMR, Fourier transform infrared spectroscopy, ultra performance liquid chromatography (UPLC) or thin layer chromatography (TLC). Upon completion of the reaction, the unreacted thiol acid (IV) can be removed under reduced pressure to give the crude thioester (V).

[0127] The crude product may be used in subsequent steps of the process or the related compounds may be purified using methods known in the art, including but not limited to solvent extraction, filtration and chromatography.

[0128] Step c) Hydrolysis In this step of the process shown in Figure 3, the thioester (V) is deprotected to give the corresponding polythiol (VI). This step could be carried out using a reductive method in which the thioester (IV) is reduced with LiAlH4, followed by hydrolysis to give the thiol (VI). However, in important embodiments, the deprotection step is carried out by acid- or base-catalyzed hydrolysis.

[0129] In this embodiment, the acid or base catalyst should be present in the reaction mixture in an amount of 0.05-0.25 moles per mole of the thioester (IV). For acid-based hydrolysis, common acids include H2SO4 and HCl. For base-catalyzed hydrolysis, organic base catalysts are preferred, non-limiting examples of which include: pyridine; dimethylaminopyridine (DMAP); proline; triazabicyclodecene (TBD); diazabicycloundecene (DBU); hexahydromethylpyrimidopyridine (MTBD); diazabicyclononane (DBN); tetramethylguanidine (TMG); and triethylenediamine (TED, 1,4-diazabicyclo[2.2.2]octane).

[0130] The nucleophilic species (H) in the hydrolysis can be water. However, it is preferred that the nucleophile is a C1-C4 alkanol; it can be mentioned that the use of methanol (MeOH) is particularly preferred. When a C1-C4 alkanol is used, the reaction product will be a thiol (VI) and a C1-C4 alkyl ester. Apart from that, the nucleophile (H) should be present in at least a stoichiometric amount relative to the moles of thioester groups of compound (IV). An excess of nucleophile can help to drive the reaction to completion.

[0131] Although not strictly required, the described reaction of step c) can be carried out in the presence of an inert aprotic solvent. The use of ethereal solvents is preferred, which can include tetrahydrofuran (THF); 2-methyltetrahydrofuran (2-MeTHF); 1,2-dimethoxyethane; and 1,3-dioxolane.

[0132] The reaction does not have to be carried out under reflux conditions, but it is preferred to do so. If reflux conditions are not used, carrying out the reaction at room temperature is not practically precluded, but the use of elevated temperatures, for example at least 50° C. or at least 75° C., can facilitate the reaction. Such elevated temperatures may in fact be required for acid-catalyzed hydrolysis.

[0133] The process pressure is not critical: the reaction can therefore be carried out at subatmospheric, atmospheric or superatmospheric pressure, although atmospheric pressure or slightly higher is preferred. In this connection, reference can be made to pressures of 50 to 200 kPa, for example 100 to 200 kPa.

[0134] The progress of the above reaction is as follows: 1 The reaction can be monitored by known techniques, which may include H NMR, Fourier transform infrared spectroscopy, ultra-performance liquid chromatography (UPLC) or thin layer chromatography (TLC). Once the reaction is complete, the reaction mixture can be concentrated under evaporative conditions to remove excess water, C1-C4 alkanol and / or solvent to obtain crude polythiol (VI). The crude product may be purified using methods known in the art, including, but not limited to, solvent extraction, filtration and chromatography.

[0135] Second Method Embodiment In this process embodiment, intermediate compounds of formula VB, VC or VD are synthesised in a single step (α) from compounds of formula IB, IC or ID, respectively.

[0136] Process α) In this step of the above described process shown in FIG. 4, a compound of formula IB, IC or ID is reacted with a compound of general formula VII: [ka] [Wherein, Y is a halogen; R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene, C6-C 18 Arylene group or C7-C 18 is an aralkylene group; R 2 is H or methyl; and R 3 is C1-C6 alkyl, C6-C 18 Aryl, C7-C 18 Alkylaryl or C7-C 18 aralkyl] and reacting the thiol acid ester with the thiol acid ester having the formula:

[0137] In most cases, chlorides (Y=Cl) are preferred due to their lower cost, but bromides and iodides can be more reactive, especially for higher molecular weight compounds. 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group or C2-C 18 It is preferably a thioalkylene group. More specifically, R 1 is unsubstituted C1-C 12 is an alkylene group; R 2 is H or Me; R 3 C1-C4 alkyl, C6 aryl, C7-C 18 Alkylaryl or C7-C 18 In an important embodiment, R is an aralkyl group. 1 is an unsubstituted C1-C4 alkylene group; R 2 is H or Me; R 3is C1-C4 alkyl.

[0138] Exemplary thiolates according to Formula VII include: S-(3-chloropropyl)ethanethioate; S-(3-bromopropyl)ethanethioate; and S-(3-iodopropyl)ethanethioate.

[0139] It is intended that each hydroxyl group in the compound of formula I is subjected to substitution, therefore, the thiol acid ester compound (VII) should be present in at least a stoichiometric equivalent amount relative to the moles of said hydroxyl groups. The reaction mixture may in particular contain said thiol acid ester compound (VII) in 1-2 molar equivalents relative to the moles of hydroxyl groups of formula I. Preferably, the thiol acid ester compound (VII) is reacted in 1.2-1.8 molar equivalents relative to the moles of hydroxyl groups of formula I.

[0140] The base present should be present in at least a stoichiometric amount from the reaction, since it reacts with the halogen acid liberated during the reaction. However, the reaction can be operated in the presence of an excess of base, and thus the base can be present in the reaction mixture in an amount of 1 to 5 molar equivalents relative to the amount of compound (I). It is preferred that the base is present in an amount of 1.5 to 3 molar equivalents or 1.5 to 2.5 molar equivalents relative to the amount of compound (I).

[0141] Without intending to limit the invention, the base should desirably consist of at least one compound selected from alkali metals, alkaline earth metals, alkali metal (C1-C4) alkoxides, alkaline earth metal (C1-C4) alkoxides, alkali metal carbonates, alkaline earth metal carbonates, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal hydrides and alkaline earth metal hydrides. The use of at least one of potassium carbonate, sodium carbonate and calcium carbonate may be preferred.

[0142] In certain embodiments, the addition of a neutral alkali metal salt to the reaction mixture can have a positive effect on the yield of the thioester reaction product (V). Exemplary alkali metal salts include: sulfates, sulfites, sulfides, halides, nitrates, nitrites, cyanides, borates, phosphates, monohydrogen phosphates, dihydrogen phosphates, phosphites, acid phosphites, and carboxylates, such as acetates, formates, propionates, oxalates, tartrates, succinates, maleates, and adipates.

[0143] A small amount of neutral alkali metal salt, for example 0.01-0.05 mole per mole of compound (I), has a yield-improving effect, but the amount of said neutral salt should not exceed the amount of the basic catalyst contained in the reaction mixture.

[0144] This step is further carried out in the presence of an inert aprotic solvent. Examples of suitable aprotic solvents that can be used alone or in combination include pentane, hexane, heptane, cyclopentane, cyclohexane, cycloheptane, dimethyl ether, chloroform, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, 2-propylbenzene (cumene), 2-isopropyltoluene (o-cymol), 3-isopropyltoluene (m-cymol), 4-isopropyltoluene (p-cymol), 1,3,5-trimethylbenzene (mesitylene), acetonitrile, N,N-di(C1-C4) alkyl acyl amides, such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide. esters such as (C1-C8) alkyl acetates, ethoxydiglycol acetate, dimethyl glutarate, dimethyl maleate, dipropyl oxalate, ethyl lactate, benzyl benzoate, butyl octyl benzoate and ethylhexyl benzoate; ketones such as acetone, ethyl ketone, methyl ethyl ketone (2-butanone), methyl isobutyl ketone; ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF) and 1,2-dimethoxyethane; 1,3-dioxolane; dimethyl sulfoxide (DMSO); and dichloromethane (DCM).

[0145] Although not critical, it is preferred that the reaction in this step be carried out under anhydrous conditions. If necessary, exposure to atmospheric moisture can be avoided by providing an inert, dry gas blanket to the reaction vessel. Dry nitrogen, helium and argon can be used as blanket gases, but care should be taken when using common nitrogen gas as a blanket, as such nitrogen may not be sufficiently dry due to its sensitivity to moisture entrainment; nitrogen may require an additional drying step before use here.

[0146] The reaction does not have to be carried out under reflux conditions, but it is preferred to do so. If reflux conditions are not used, running the reaction at 0°C is not practically precluded, but the use of elevated temperatures, for example at least 50°C or at least 75°C, can facilitate the reaction. However, for exothermic reactions, some cooling may be required as the reaction proceeds.

[0147] The process pressure of step α) is not critical: the reaction can therefore be carried out at subatmospheric, atmospheric or superatmospheric pressure, although atmospheric pressure or slightly higher pressures are preferred. In this connection, mention may be made of pressures between 50 and 200 kPa, for example between 100 and 200 kPa.

[0148] The progress of the above reaction is as follows: 1 The reaction can be monitored by known techniques, including H NMR, Fourier transform infrared spectroscopy, ultra-performance liquid chromatography (UPLC) or thin layer chromatography (TLC). Once the reaction is complete, the excess base present in the reaction mixture can be quenched with a suitable acid, such as hydrochloric acid. Also, the inert aprotic solvent can be removed under reduced pressure.

[0149] The crude product (VB, VC or VD) may then be isolated from the mixture obtained by the reaction and may be used as such in the subsequent steps of the process. Alternatively, the related compounds may be purified using methods known in the art, including but not limited to solvent extraction, filtration and chromatography.

[0150] Step β) Hydrolysis This step of the process for deprotecting the thioester of formula VB, VC or VD to give the corresponding polythiol (VIB, VIC or VID), respectively, corresponds to step c) above and is illustrated in FIG.

[0151] Third Method Embodiment In this process embodiment, an intermediate compound of formula VA is formed from a compound of formula IA in a two-step process, as shown in FIG. 5 attached hereto.

[0152] process aa) In this step of the above-described process shown in FIG. 5, a compound of formula IA is reacted with a compound of general formula VII: [ka] [Wherein, Y is a halogen; R 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group, C2-C 18 Thioalkylene, C6-C 18 Arylene group or C7-C 18 is an aralkylene group; R 2 is H or methyl; and R 3 is C1-C6 alkyl, C6-C 18 Aryl, C7-C 18 Alkylaryl or C7-C 18 aralkyl] with a thiolate compound having the formula VIIIA to form an intermediate compound of formula VIIIA.

[0153] In most cases, chlorides (Y=Cl) are preferred due to their lower cost, but bromides and iodides can be more reactive, especially for higher molecular weight compounds. 1 is C1-C 18 Alkylene group, C2-C 18 Oxyalkylene group or C2-C 18 It is preferably a thioalkylene group. More specifically, R 1 is unsubstituted C1-C 12 is an alkylene group; R 2 is H or Me; R 3 C1-C4 alkyl, C6 aryl, C7-C 18Alkylaryl or C7-C 18 In an important embodiment, R is an aralkyl group. 1 is an unsubstituted C1-C4 alkylene group; R 2 is H or Me; R 3 is C1-C4 alkyl.

[0154] Exemplary thiolates according to Formula VII include: S-(3-chloropropyl)ethanethioate; S-(3-bromopropyl)ethanethioate; and S-(3-iodopropyl)ethanethioate.

[0155] Each hydroxyl group in the compound of formula IA is intended to be subjected to substitution, therefore, the thiolate compound (VII) should be present in at least a stoichiometric equivalent amount relative to the moles of said hydroxyl groups. The reaction mixture may in particular contain said thiolate compound (VII) in 1 to 2 molar equivalents relative to the moles of hydroxyl groups of formula I. Preferably, the thiolate compound (VII) is reacted in 1.2 to 1.8 molar equivalents relative to the moles of hydroxyl groups of formula I.

[0156] The base present should be present in at least the stoichiometric amount from the reaction, since it reacts with the halogen acid liberated during the reaction. However, the reaction can be operated in the presence of an excess of base, and thus the base can be present in the reaction mixture in an amount of 1 to 5 molar equivalents relative to the amount of compound (I). It is preferred that the base is present in an amount of 1.5 to 3 molar equivalents or 1.5 to 2.5 molar equivalents relative to the amount of compound (I).

[0157] Without intending to limit the invention, the base should desirably consist of at least one compound selected from alkali metals, alkaline earth metals, alkali metal (C1-C4) alkoxides, alkaline earth metal (C1-C4) alkoxides, alkali metal carbonates, alkaline earth metal carbonates, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal hydrides and alkaline earth metal hydrides. The use of at least one of potassium carbonate, sodium carbonate and calcium carbonate may be preferred.

[0158] In certain embodiments, the addition of a neutral alkali metal salt to the reaction mixture can have a positive effect on the yield of the thioester reaction product (V). Exemplary alkali metal salts include: sulfates, sulfites, sulfides, halides, nitrates, nitrites, cyanides, borates, phosphates, monohydrogen phosphates, dihydrogen phosphates, phosphites, acid phosphites, and carboxylates, such as acetates, formates, propionates, oxalates, tartrates, succinates, maleates, and adipates.

[0159] A small amount of neutral alkali metal salt, for example 0.01-0.05 mole per mole of compound (I), has a yield-improving effect, but the amount of said neutral salt should not exceed the amount of the basic catalyst contained in the reaction mixture.

[0160] This step is further carried out in the presence of an inert aprotic solvent. Examples of suitable aprotic solvents that can be used alone or in combination include pentane, hexane, heptane, cyclopentane, cyclohexane, cycloheptane, dimethyl ether, chloroform, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, 2-propylbenzene (cumene), 2-isopropyltoluene (o-cymol), 3-isopropyltoluene (m-cymol), 4-isopropyltoluene (p-cymol), 1,3,5 trimethylbenzene (mesitylene), acetonitrile, N,N-di(C1-C4) alkyl acyl amides such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide. esters such as (C1-C8) alkyl acetates, ethoxydiglycol acetate, dimethyl glutarate, dimethyl maleate, dipropyl oxalate, ethyl lactate, benzyl benzoate, butyl octyl benzoate and ethylhexyl benzoate; ketones such as acetone, ethyl ketone, methyl ethyl ketone (2-butanone), methyl isobutyl ketone; ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF) and 1,2-dimethoxyethane; 1,3-dioxolane; dimethyl sulfoxide (DMSO); and dichloromethane (DCM).

[0161] Although not critical, it is preferred that the reaction in this step be carried out under anhydrous conditions. If necessary, exposure to atmospheric moisture can be avoided by providing an inert, dry gas blanket to the reaction vessel. Dry nitrogen, helium and argon can be used as blanket gases, but care should be taken when using common nitrogen gas as a blanket, as such nitrogen may not be sufficiently dry due to its sensitivity to moisture entrainment; nitrogen may require an additional drying step before use here.

[0162] The reaction does not have to be carried out under reflux conditions, but it is preferred to do so. If reflux conditions are not used, carrying out the reaction at 0°C is not practically precluded, but the use of elevated temperatures, for example at least 50°C or at least 75°C, can facilitate the reaction. However, for exothermic reactions, some cooling may be required as the reaction proceeds.

[0163] The process pressure of step aa) is not critical: the reaction can therefore be carried out at subatmospheric, atmospheric or superatmospheric pressure, although atmospheric pressure or slightly higher pressures are preferred. In this connection, mention may be made of pressures between 50 and 200 kPa, for example between 100 and 200 kPa.

[0164] The progress of the above reaction is as follows: 1 The reaction can be monitored by known techniques, which can include H NMR, Fourier transform infrared spectroscopy, ultra-performance liquid chromatography (UPLC) or thin layer chromatography (TLC). Upon completion of the reaction, the crude product (Formula VIII) itself can be used in the subsequent steps of the process. Alternatively, the product can be separated from the reaction mixture and purified using methods known in the art, including, but not limited to, solvent extraction, filtration and chromatography. Prior to such separation and purification, the reaction mixture should be quenched using an appropriate acid, such as hydrochloric acid, and the inert aprotic solvent should be removed under reduced pressure.

[0165] process bb) In this step, the intermediate allyl-functional compound (VIIIA) of step aa) is reacted with a thiol acid (IV) to give a thioester of formula VA. The reactant thiol acid (IV) has the general formula: R 3 -C(=O)-SH (IV) [In the formula, R 3 is C1-C6 alkyl, C6-C 18 Aryl, C7-C 18 Alkylaryl or C7-C 18 aralkyl] Preferably, R 3 C1-C4 alkyl, C6 aryl, C7-C 18 Alkylaryl or C7-C 18 It is aralkyl. 3 may be the same as or different from the substituent of reactant VII above.

[0166] The reaction conditions described in step b) above are applicable to this reaction step bb) and will not be repeated here for the sake of brevity.

[0167] Step cc) Hydrolysis This step in the process for deprotecting the thioester (VA) to give the corresponding polythiol (VIA) corresponds to step c) above and is illustrated in FIG.

[0168] Exemplary Compounds According to an exemplary, but non-limiting embodiment of the present invention, there are provided compounds represented by the following formulas VIAa, VIBa and VICa. [ka]

[0169] According to the above reaction process, these compounds are i) According to a first method embodiment, R 1 =CH2 and R 2 Allylating reagents (II) where X is -H, in particular allyl bromide (X=Br) or ethyl prop-2-enyl carbonate (X is -OC=O)OEt); and thiol acid thioacetate (R 3 By using =Me); ii) According to a second method embodiment, for compounds VIBa and VICa, Y=halogen, R 1 =CH2, R 2 =H, R 3 by using a thiolate ester reagent (VII) in which is C1-C4 alkyl; or iii) According to a third method embodiment, for compound VIAa, Y=halogen, R1 =CH2, R 2 =H, R 3 is C1-C4 alkyl, and then thioacetic acid (R 3 By using =Me), It can be formed from compounds IA, IB and IC.

[0170] Compositions containing the thiol compounds of the present invention The polythiol compounds of the present disclosure are considered to be versatile and therefore have many applications.It is certainly expected that the thiol compounds themselves can be useful as curing agents or other reactive components of one-component (1K) or two-component (2K) curable compositions.Such one-component (1K) or two-component (2K) curable compositions can be, in particular, coating, adhesive or sealant compositions.It is not excluded that the one-component (1K) or two-component (2K) compositions can be dual-cure compositions.

[0171] In an important embodiment of the present disclosure, the curable composition comprises: a) at least one polythiol as described above; b) at least one thiol-reactive compound, wherein the or each thiol-reactive compound has at least one functional group (F) selected from the group consisting of an epoxy group; an oxetane group; a cyclic carbonate group; a cyclic anhydride group; a 1-oxacycloalkan-2-one group; an ethylenically unsaturated group; an alkyne group; and an isocyanate group.

[0172] Certainly, a given thiol-reactive compound b) may have more than one different functional group in its structure, for example, an epoxy group and a (meth)acrylate group. Exemplary thiol-reactive compounds b) include, but are not limited to, epoxide compounds; ethylenically unsaturated compounds; epoxy (meth)acrylate compounds having at least one (meth)acrylate group and at least one epoxy group; and polyisocyanates. For ethylenically unsaturated groups, a useful reference is Hoyle et al., Thiol-Enes: Chemistry of the Past with Promise for the Future J.Polym.Sci.A Polym.Chem.2004,42:5301(2004).

[0173] The number of functional groups (F) that the thiol-reactive compound has is not particularly limited, and for example, compounds having 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 functional groups can be used. Furthermore, the thiol-reactive compound can be a low molecular weight substance having a number average molecular weight (Mn) of less than 500 g / mol, or an oligomeric or polymeric substance having a number average molecular weight (Mn) of at least 500 g / mol. Of course, mixtures of thiol-reactive compounds b) can also be used.

[0174] The following examples are illustrative of the present invention and are not intended to limit the scope of the invention in any way. EXAMPLES

[0175] The following commercially available compounds are used in the examples: Thioacetic acid: available from Tokyo Chemical Industry Co., Ltd. Azobisisobutyronitrile (AIBN): available from Sigma-Aldrich Triazabicyclodecene (TBD): available from Sigma-Aldrich

[0176] Example 1: Synthesis of compound VIAa [ka]

[0177] Step a): Allylation [ka]

[0178] A suspension of eugenol (9.8 g, 60 mmol), K2CO3 (16.6 g, 120 mmol) and allyl bromide (7.8 mL, 90 mmol) in acetone (140 mL) was stirred at 60 °C for 12 h. After cooling to ambient temperature, the suspension was filtered through Celite to remove insoluble solids. The filtrate was concentrated on a rotary evaporator and the resulting crude product was purified by silica gel flash column chromatography eluting with a mixture of cyclohexane (90 wt%) and ethyl acetate (10 wt%) to give the allylated product (IIIAa) as a pale yellow liquid in 99% yield.

[0179] 1 H NMR(300MHz,CDCl3)δ:6.82(d,J=8.0Hz,1H),6.75-6.65(m,2H),6.22-5.84(m,2H),5.39(dq,J=17.2,1.6Hz,1H),5.27( dq,J=10.5,1.4Hz,1H),5.18-5.00(m,2H),4.59(dt,J=5.4,1.5Hz,2H),3.87(s,3H),3.34(dtt,J=6.7,1.3,0.6Hz,2H). 13 C NMR(75MHz,CDCl3)δ:149.51,146.44,137.75,133.68,133.18,120.44,117.88,115.72,113.73,112.35,77.16,70.13,55.96,39.92. C 13 H 16 ESI-MS (m / z) calculated for O2: 204.1144, found: 204.1142.

[0180] Steps b) and c) Thiol-ene reaction followed by hydrolysis [ka]

[0181] The allylated product (IIIAa: 6.1 g, 30 mmol) obtained above was reacted with thioacetic acid (7.5 ml, 45 mmol) in the presence of azobisisobutyronitrile (AIBN, 300 mg, 1.8 mmol) at 80° C. for 20 hours. Unreacted thioacetic acid was removed under reduced pressure to obtain a crude dithioester intermediate.

[0182] The resulting crude dithioester was hydrolyzed in the presence of triazabicyclodecene (TBD, 2.4 g, 9.0 mmol) in methanol (83 ml) at 70° C. for 15 h. The reaction mixture was concentrated on a rotary evaporator and the residual oil was dissolved in dichloromethane and washed with water. The organic phase was dried over MgSO4 to give the desired product (VIAa) in 93% yield as a yellow liquid after removal of volatiles.

[0183] 1 H NMR(300MHz,CDCl3)δ:6.87-6.77(m,1H),6.75-6.62(m,2H),4.19-3.97(m,2H),3.84(s,3H),2.81-2.60(m,4H ),2.60-2.45(m,2H),2.10(tt,J=7.0,6.1Hz,2H),2.00-1.81(m,2H),1.44(t,J=8.1Hz,1H),1.39-1.31(m,1H). 13 C NMR(75MHz,CDCl3)δ:149.54,146.58,134.51,120.44,113.76,112.39,77.16,67.21,55.99,35.65,33.99,33.45,24.01,21.43. C 13 H 20 ESI-MS (m / z) calculated for O2S2: 272.0899, found: 272.0897.

[0184] Example 2: Synthesis of compound VIBa [ka]

[0185] Step a) Allylation to obtain allyl-3,4,5-tris(allyloxy)benzoate [ka]

[0186] A 500 mL two-neck flask equipped with a septum cap and a magnetic stir bar was charged with 200 mL of DMF and gallic acid (60 mmol, 10.21 g). The solution was cooled in an ice bath and potassium carbonate (240 mmol, 33.17 g) was added. After 5 min, allyl bromide (240 mmol, 21.17 ml) was added dropwise using a dropping funnel. The solution was stirred at 0° C. for 30 min and then at 25° C. for 48 h. 200 mL of water was added and the aqueous phase was extracted with 3×100 mL of ethyl acetate. The organic phase was washed with 100 mL of brine, then dried over MgSO4 and concentrated in vacuo. The residue was purified by silica gel chromatography (CH:EtOAc, 90:10) to give the product (IIIBa) as a pale yellow liquid (isolated yield: 82%).

[0187] 1 H NMR(300MHz,DMSO-d6)δ:7.25(s,2H),6.21-5.86(m,4H),5.43(dq,J=10.0 ,1.7Hz,2H),5.39(q,J=1.8Hz,1H),5.36(qd,J=1.6,0.5Hz,1H),5.32-5.27 (m,2H),5.26-5.24(m,1H),5.17(ddt,J=10.4,1.9,1.3Hz,1H),4.78(dt,J =5.4,1.5Hz,2H),4.63(dt,J=5.0,1.6Hz,4H),4.54(dt,J=5.7,1.4Hz,2H). 13C NMR(75MHz,DMSO)δ:164.85,151.90,141.13,134.35,133.39,132.61,124.55,117.76,117.35,117.15,107.98,73.15,69.14,65.11,39.52. C 19 H 22 ESI-MS (m / z) calculated for O5: 331.1545, found: 331.1551.

[0188] Steps b) and c) Thiol-ene reaction followed by hydrolysis [ka]

[0189] In the first step, allyl-3,4,5-tris(allyloxy)benzoate (22.3 g, 68 mmol) was reacted with thioacetic acid (29 ml, 408 mmol) and AIBN (2.23 g, 13.6 mmol) by stirring the mixture at 80° C. for 20 h. Unreacted thioacetic acid was then removed under reduced pressure. The compound was extracted with DCM:3×H2O. The organic phase was separated and dried over MgSO4. The volatiles were removed to give the product.

[0190] For the second step, the compound was dissolved in 400 ml of dry THF and 1.1 equivalents of concentrated HCl (37.8 g) in 90 ml of dry MeOH was added to the solution. The mixture was degassed under Ar for 10 min and the solution was stirred at 70° C. for 22 h. Finally, the solvent was removed and the tetrathiol was extracted with DCM:3×H2O. The organic phase was separated and dried over MgSO4. The volatiles were removed to give the final product. 5×10 -2 Further purification was achieved by vacuum distillation at 120° C. and mbar. The isolated yield was 75%.

[0191] 1H NMR(300MHz,CDCl3)δ:7.28(s,2H),4.42(t,J=6.2Hz,2H),4.13(dt,J=10.8,5.8 Hz,6H),2.88-2.60(m,8H),2.08(dp,J=26.9,6.6Hz,8H),1.45(q,J=8.1Hz,4H). 13 C NMR(101MHz,CDCl3)δ:166.15,152.59,141.94,125.32,108.23,77.16,71.12,67.03,63.32,34.40,33.35,33.02,21.38. C 19 H 30 O5S4[M+Na] + ESI-MS (m / z) calculated for: 489.0873, found: 489.0886. EA:C 19 H 30 Calculated for O5S4: C, 48.90; H, 6.48; S, 27.48. Found: C, 48.02; H, 7.32; S, 26.96.

[0192] Example 3: Synthesis of Compound VICa [ka]

[0193] Previous step: Preparation of tris(3-methoxy-4-hydroxyphenyl)methane (ICa) [ka]

[0194] Vanillin (76.1 g, 1 eq.) and guaiacol (310.4 g, 5 eq.) were charged into a 1 L single-neck round-bottom flask under magnetic stirring. Once vanillin was completely dissolved, zinc chloride (ZnCl2, 6.8 g, 0.1 eq.) and p-toluenesulfonic acid (PTSA, 9.5 g, 0.1 eq.) were added. The mixture was kept in open air at 50 °C for 5 days. The progress of the reaction was monitored by thin layer chromatography (TLC) plates in ethyl acetate / hexane (v / v=1 / 1) solution. It was then washed three times with hot water (>70 °C) to remove the catalyst (ZnCl2 and PTSA). Unreacted guaiacol was removed and recycled under reduced pressure at 140 °C using a rotary evaporator. The resulting viscous liquid was placed in a vacuum oven at 90 °C for 12 h. The crude product (ICa) was further purified by crystallization in chloroform. The obtained triphenol compound was a red powder (isolated yield: 63%). 1 Based on 1 H NMR, there is one molecule of chloroform present as the crystallizing molecule.

[0195] 1 H NMR(300MHz,DMSO-d6)δ:8.76(s,3H,OH),6.74-6.60(m,6H,Ar-H),6.44(dd,J=8.3,1.9Hz,3H,Ar-H),5.23(s,1H,Ar3-CH),3.65(s,9H,-CH3). 13 C NMR(75MHz,CDCl3)δ:147.21,Ar-C,144.67,Ar-C,135.72,Ar-C,121.19,Ar-C,115.10,Ar-C,113.27,Ar-C,55.58,Ar3-C,54.66,-CH3,39.52. C 22 H 22 ESI-MS (m / z) calculated for O6: 382.1410, found: 382.1409.

[0196] Step a) Allylation to tris(4-(allyloxy)-3-methoxyphenyl)methane [ka]

[0197] A suspension of triphenol (15.3 g, 40 mmol), K2CO3 (28.193 g, 204 mmol) and allyl bromide (17.63 mL, 204 mmol) in acetone (250 mL) was stirred at 70 °C for 18 h. After cooling to ambient temperature, the suspension was filtered through a Celite pad and washed with acetone. The filtrate was evaporated and the crude product (IIICa) was purified by layer crystallization in acetone:pentane. The final product was a yellow powder (isolated yield: 82%).

[0198] 1 H NMR(400MHz,CDCl3)δ:6.79(d,J=8.3Hz,3H,Ar-H),6.66(d,J=2.1Hz,3H,Ar-H),6.56(dd,J=8.3 ,2.1Hz,3H,Ar-H),6.08(ddt,J=17.3,10.7,5.4Hz,3H),5.39(dt,J=17.1,1.5Hz,4H,Ar3-CH,-C H 2), 5.26(dq, J=10.5, 1.4Hz, 3H, -C H ), 4.58(dt, J=5.5, 1.5Hz, 6H, -C H 2), 3.75(s,9H,-CH3). 13 C NMR(101MHz,CDCl3)δ:149.18,Ar-C,146.47,Ar-C,137.33,Ar-C,133.53,Ar-C,121.34,- C H,117.95,- C H2,113.12,Ar-C,113.00,Ar-C,77.16,69.92,- C H2,55.93,- C H3,55.51,Ar3-C. C 31 H 34 ESI-MS (m / z) calculated for O6: 502.2349, found: 502.2345.

[0199] Steps b) and c) Thiol-ene reaction followed by hydrolysis [ka]

[0200] In the first step, tris(4-(allyloxy)-3-methoxyphenyl)methane (20.1 g, 40 mmol) was reacted with thioacetic acid (20 ml, 180 mmol) and AIBN (1.55 mg, 9.6 mmol) by stirring the mixture at 80° C. for 24 hours. The conversion was 1 The reaction can be monitored by H NMR. Unreacted thioacetic acid was then removed under reduced pressure. The compound was extracted with DCM:3×H2O. The organic phase was separated and dried over MgSO4. The volatiles were removed to give the intermediate thioester product.

[0201] For the second step, the compound was dissolved in 100 ml of dry THF and 1.1 equivalents of concentrated HCl (12.9 g) in 40 ml of dry MeOH was added to the solution. The mixture was degassed under Ar for 10 min and the solution was stirred at 60° C. for 14 h. Finally, the solvent was removed and the trithiol was extracted with DCM:3×H2O. The organic phase was separated and dried over MgSO4. The volatiles were removed to give the final product. 5×10 -2 Further purification was carried out by vacuum distillation at 120° C. and mbar, and the final product was a condensed orange liquid (isolated yield: 85%).

[0202] 1 H NMR(300MHz,CDCl3)δ:6.83-6.74(m,3H,Ar-H),6.66(d,J=2.1Hz,3H,Ar-H),6.62-6.52(m,3H,Ar-H),5.35(d,J=2.8Hz,1H,Ar3-C H ),4.08(t,J=6.1Hz,6H,-CH2),3.73(s,9H,-C H 3),2.71(dt,J=8.2,6.9Hz,6H,-CH2),2.17-1.99(m,6H,-CH2),1.42(t,J=8.1Hz,3H,-S H ). 13C NMR(75MHz,CDCl3)δ:149.20,Ar-C,146.66,Ar-C,137.29,Ar-C,121.36,Ar-C,113.25,Ar-C,113.04,Ar-C,77.16,66.34,- C H2,55.89,- C H3,55.41,Ar3- C H,33.31,- C H2,21.29,- C H2. C 31 H 40 ESI-MS (m / z) calculated for O6S3: 627.1884, found: 627.1888.

[0203] In view of the above description and examples, it will be apparent to one skilled in the art that equivalent modifications can be made thereto without departing from the scope of the claims.

Claims

1. General formula VIA, VIB or VIC: 【Chemistry 1】 [In the formula, R １ is C １ -C １８ Alkylene group, C ２ -C １８ Oxyalkylene group, C ２ -C １８ Thioalkylene group, C ６ -C １８ Arylene or C ７ -C １８ an aralkylene group; and R ２ is H or methyl. A polythiol compound having the formula:

2. R １ is unsubstituted C １ -C １２ Alkylene groups, preferably unsubstituted C １ -C ４ is an alkylene group, and R ２ The compound of claim 1 , wherein is H or Me.

3. VIAa, VIBa or VICa: 【Chemistry 2】 3. The compound according to claim 1 or 2, selected from:

4. General formula VIA, VIB, VIC or VID 【Chemistry 3】 [In the formula, R １ is C １ -C １８ Alkylene group, C ２ -C １８ Oxyalkylene group, C ２ -C １８ Thioalkylene group, C ６ -C １８ Arylene or C ７ -C １８ an aralkylene group; and R ２ is H or methyl.

1. A method for producing a compound having the formula: The method comprises treating a vehicle comprising a vehicle having the general formula IA, IB, IC or ID: 【Chemistry 4】 and further comprising providing a compound having the formula: a) reacting a compound of formula IA, IB, IC or ID with a compound of formula: X-(R １ )-C(R ２ )=CH ２ (II) wherein X is a halogen or a -OC(=O)OR° group; R° is C １ -C ４ is an alkyl group; R １ is C １ -C １８ Alkylene group, C ２ -C １８ Oxyalkylene group, C ２ -C １８ Thioalkylene group, C ６ -C １８ Arylene or C ７ -C １８ an aralkylene group; and R ２ is H or methyl. to afford the compounds of formula IIIA, IIIB, IIIC or IIID, respectively: 【Chemistry 5】 forming a compound of b) reacting said compound of formula IIIA, IIIB, IIIC or IIID with a compound of the general formula R ３ -C(=O)-SH(IV) [In the formula, R ３ is C １ -C ６ Alkyl, C ６ -C １８ Aryl, C ７ -C １８ Alkylaryl or C ７ -C １８ aralkyl] to give thiol acids (IV) having the formula VA, VB, VC or VD, respectively: 【Chemistry 6】 forming a thioester compound of the formula: c) deprotecting said thioester compound of formula VA, VB, VC or VD to form said polythiol compound of formula VIA, VIB, VIC or VID, respectively; A method comprising:

5. The primary allyl compound (II) is R° is C １ -C ２ is alkyl; R １ is unsubstituted C １ -C １２ Alkylene groups, preferably unsubstituted C １ -C ４ an alkylene group; and R ２ is H or Me The method according to claim 4, characterized in that

6. The method of claim 5, wherein the primary allyl compound (II) is selected from the group consisting of 3-chloro-1-propene, 3-bromoprop-1-ene; 3-iodoprop-1-ene; methyl prop-2-enyl carbonate; and ethyl prop-2-enyl carbonate.

7. The method according to any one of claims 4 to 6, wherein the primary allyl compound (II) is reacted in an amount of 1 to 2 molar equivalents relative to the number of moles of the hydroxyl group of formula I.

8. The process according to any one of claims 4 to 7, wherein the base is present in step a) in an amount of 1 to 5 molar equivalents relative to reacting compound IA, IB, IC or ID.

9. The method according to any one of claims 4 to 8, wherein the base is selected from the group consisting of potassium carbonate, sodium carbonate and calcium carbonate.

10. The thiol acid (IV) is R ３ But, C １ -C ４ Alkyl, C ６ Aryl, C ７ -C １８ Alkylaryl or C ７ -C １８ aralkyl, and 10. The method according to any of claims 4 to 9, characterized in that the thiolic acid (IV) is preferably selected from the group consisting of thioacetic acid, thiopropionic acid, thiobutyric acid, thioisobutyric acid, thiobenzoic acid, 2-methyl-thiobenzoic acid, 3-methyl-thiobenzoic acid, 4-methyl-thiobenzoic acid, 2,4-dimethyl-thiobenzoic acid and 3,5-dimethyl-thiobenzoic acid.

11. The method according to any one of claims 4 to 10, wherein the thiolic acid (IV) is reacted in an amount of 1 to 2 molar equivalents relative to the allyl group of the compound of formula IIIA, IIIB, IIIC or IIID.

12. General formula VIB, VIC or VID 【Chemistry 7】 [In the formula, R １ is C １ -C １８ Alkylene group, C ２ -C １８ Oxyalkylene group, C ２ -C １８ Thioalkylene group, C ６ -C １８ Arylene or C ７ -C １８ an aralkylene group; and R ２ is H or methyl.

1. A method for producing a compound having the formula: The method comprises providing a compound of general formula IB, IC or ID: 【Chemistry 8】 providing a compound having the formula: moreover, a) reacting a compound of formula IB, IC or ID with a compound of formula VII: 【Chemistry 9】 [In the formula, Y represents a halogen; R １ is C １ -C １８ Alkylene group, C ２ -C １８ Oxyalkylene group, C ２ -C １８ Thioalkylene group, C ６ -C １８ Arylene or C ７ -C １８ is an aralkylene group; R ２ is H or methyl; and R ３ is C １ -C ６ Alkyl, C ６ -C １８ Aryl, C ７ -C １８ Alkylaryl or C ７ -C １８ aralkyl] and reacting with a thiol acid ester compound having the formula Respectively, of formula VB, VC or VD: 【Chemistry 10】 forming a thioester compound of the formula: β) deprotecting the thioester compound of formula VB, VC or VD to form a polythiol compound of formula VIB, VIC or VID, respectively; A method comprising:

13. 13. The process according to any of claims 4 to 12, wherein the deprotection step (c),β)) is carried out by acid-catalyzed or base-catalyzed hydrolysis, said acid or base catalyst being preferably present during the deprotection step (c),β)) in an amount of 0.05 to 0.25 moles per mole of said thioester of formula VA, VB, VC or VD.

14. 14. The method of claim 13, wherein the deprotection step (c),β) is carried out by base catalyzed hydrolysis, and wherein the base is selected from the group consisting of pyridine; dimethylaminopyridine (DMAP); proline; triazabicyclodecene (TBD); diazabicycloundecene (DBU); hexahydromethylpyrimidopyridine (MTBD); diazabicyclononane (DBN); tetramethylguanidine (TMG); and triethylenediamine (TED, 1,4-diazabicyclo[2.2.2]octane).

15. Use of the polythiol compound according to any one of claims 1 to 3 as a reactive component of a one-component (1K) or two-component (2K) curable composition.

16. a) a compound of general formula VIA, VIB, VIC or VID: 【Chemistry 11】 [In the formula, R １ is C １ -C １８ Alkylene group, C ２ -C １８ Oxyalkylene group, C ２ -C １８ Thioalkylene group, C ６ -C １８ Arylene or C ７ -C １８ an aralkylene group; and R ２ is H or methyl. At least one polythiol compound having the formula: b) at least one thiol-reactive compound, wherein the or each thiol-reactive compound has at least one functional group (F) selected from the group consisting of: epoxy groups; oxetane groups; cyclic carbonate groups; cyclic anhydride groups; 1-oxacycloalkan-2-one groups; ethylenically unsaturated groups; alkyne groups; and isocyanate groups, said thiol-reactive compound b) being preferably selected from the group consisting of, but not limited to, epoxy compounds; ethylenically unsaturated compounds; epoxy (meth)acrylate compounds having at least one (meth)acrylate group and at least one epoxy group; and polyisocyanates, 1. A curable composition comprising:

17. General formula IIIC: 【Chemistry 12】 [In the formula, R １ is C １ -C １８ Alkylene group, C ２ -C １８ Oxyalkylene group, C ２ -C １８ Thioalkylene group, C ６ -C １８ Arylene or C ７ -C １８ an aralkylene group; and R ２ is H or methyl, Preferably, R １ is unsubstituted C １ -C １２ Alkylene groups, preferably unsubstituted C １ -C ４ an alkylene group; and R ２ is H or Me, More preferably, R １ is methylene; and R ２ is H] Compound.

18. General formula VID: 【Chemistry 13】 [In the formula, R １ is C １ -C １８ Alkylene group, C ２ -C １８ Oxyalkylene group, C ２ -C １８ Thioalkylene group, C ６ -C １８ Arylene or C ７ -C １８ an aralkylene group; and R ２ is H or methyl, Preferably, R １ is unsubstituted C １ -C １２ Alkylene groups, preferably unsubstituted C １ -C ４ an alkylene group; and R ２ is H or Me (wherein R ２ is H, then R １ is not a methylene group). Compound.

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