Polydithioacetals and method for manufacturing same

Abstract

The present invention relates to polydithioacetal copolymers, preferably which are degradable or biodegradable, to a method for manufacturing same by free-radical polymerization, to the uses thereof, to the use of dithiolactones as precursor comonomers in a free-radical polymerization, and to dithiolactones for the preparation of said copolymer or for the implementation of said method. More particularly, the present invention relates to a method for preparing copolymers, preferably which are degradable or biodegradable, by free-radical polymerization using in particular at least one dithiolactone monomer and at least one monomer comprising an ethylenic unsaturation.

Description

Description Title of the invention: Polydithioacetals and their manufacturing process

[0001] The present invention relates to polydithioacetal type copolymers, preferably degradable or biodegradable, their manufacturing process by radical polymerization, their uses, the use of dithiolactones as precursor comonomers in a radical polymerization, and dithiolactones for the preparation of said copolymer or for the implementation of said process.

[0002] More particularly, the present invention relates to a process for preparing copolymers, preferably degradable or biodegradable, by radical polymerization, in particular using at least one dithiolactone type monomer and at least one monomer comprising an ethylenic unsaturation.

[0003] The majority of synthetic polymers are currently synthesized by free radical polymerization of vinyl monomers such as ethylene, methyl methacrylate, styrene, and vinyl acetate. Free radical synthesis processes have the advantage of tolerating a wide range of functionalities, thus enabling the synthesis of numerous materials. The application of controlled free radical polymerization techniques, developed towards the end of the 20th century, ème century, also allows the synthesis of polymers and copolymers of complex architecture, for example block, gradient or star copolymers, with control of the average molar mass of the polymer as well as the distribution of molar masses.

[0004] One of the main disadvantages of polymers produced by radical polymerization is their difficulty in degrading. This is because the different monomer units are linked together by carbon-carbon (CC) bonds, which are highly resistant to degradation. This can lead to environmental damage and also limit the application of these polymers in the medical field, where it is important to avoid the accumulation of high molecular weight polymers in the body.

[0005] One way to introduce degradability into synthetic polymers obtained by radical polymerization is to use a cyclic comonomer that polymerizes via radical ring-opening polymerization (RROP). These monomers are primarily of two types: vinyl and exo-methylene. When the vinyl or exo-methylene cyclic comonomer carries a degradable function, this function can be incorporated into the polymer backbone, making the polymer itself degradable.

[0006] The polymerization of these monomers proceeds by the addition of a radical to a double bond, followed by the opening of the ring and the generation of a linear species according to the following reaction schemes (1) and (2), relating respectively to the vinylic and exo-methylene monomers:

[0007] [Chem 1] Reaction scheme (1)

[0008] [Chem 2] Reaction scheme (2).

[0009] Among vinyl monomers, vinyl cyclopropanes, introduced in the 1960s, are a notable example. Among exo-methylene monomers, ketene acetals, introduced in the 1980s, are particularly noteworthy, notably 2-methylene-1,3-dioxane (MDO), which is transformed into an ester during radical polymerization [with Y = Y' = O in reaction scheme (2)]. Generally, ketene acetals copolymerize readily with vinyl esters and vinyl ethers, but less readily with styrenic monomers, (meth)acrylates, and (meth)acrylamides. Furthermore, they are difficult to synthesize and are often obtained in relatively low yields. Other exo-methylene type monomers such as cyclic allylic sulfides (e.g. 2-methyl-7-methylene-1,5-dithiacyclooctane) have also been described.

[0010] More recently, the use of a thionolactone, dibenzo[c,e]oxepan-5-thione (DOT), has been described in radical polymerization. Copolymers of this monomer with acrylonitrile, N,N-dimethyl acrylamide, poly(ethylene glycol)methyl ether acrylate (PEGA), methyl acrylate, and maleimides have been prepared. However, DOT is inert in the presence of methyl methacrylate and can delay the radical polymerization of styrene and / or be poorly incorporated into the polymer backbone; moreover, it inhibits the polymerizations of vinyl acetate and N-vinylpyrrolidone. Furthermore, the synthesis of DOT requires several steps with moderate yields. Other thionolactones such as y-phenyl-y-butyrothionolactone and 4-thionophthalide, were tested in copolymerization with different monomers and proved to be inert.The use of thionocaprolactone has proven inert towards activated monomers such as acrylic and styrenic monomers [Ivanchenko et al., Polymer Chemistry, 2021, 12, 1931-1938]. Other thionolactide-type monomers have also been proposed [Ivanchenko et al., Polymer Chemistry, 2022, 13, 5525-5529] for radical polymerization with styrene. However, chemical degradation has been incomplete, and the average molar masses obtained remain low (Mn on the order of 4 to 5 kg / mol). In the two aforementioned publications, dithioacetal motifs were not detected in the described copolymers.

[0011] Therefore, there is a need for synthetic processes that allow simple access, preferably with good yields, to novel synthetic polymers with varied structures, ideally based on styrene and / or acrylic units, while ensuring good degradability, or even good biodegradability, and / or higher average molar masses. There is also a need for precursor monomers capable of reacting with comonomers of varied structures, preferably with activated comonomers such as styrenes and / or acrylates.

[0012] Surprisingly, the inventors developed a radical polymerization process that enabled them to achieve these goals, with the process offering a wide range of reactivity.

[0013] The present invention therefore has as its first object a polydithioacetal type copolymer, preferably degradable or biodegradable, comprising one or more dithioacetal units of the following formula (Ul):

[0014] [Chem 3] (Ul) in which: - X is an oxygen atom, a sulfur atom, or a divalent alkylene radical -(Chhju- in which u is an integer from 1 to 4, and preferably u is 1; - when X is an oxygen atom or a sulfur atom, R 1 and R 2 , independently of each other, represent a hydrogen atom, a halogen atom, or a group chosen from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, and an optionally substituted haloalkylene-phenyl radical, - when X is a divalent alkylene radical -(Chhju-) in which u is an integer from 1 to 4, and preferably u is 1, ■ R 1 and R 2 , independently of each other, represent a hydrogen atom, a halogen atom, or a group selected from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, and an optionally substituted haloalkylene-phenyl radical; or ■ R 1 represents a hydrogen atom or a halogen atom, and R 2 represents a group of formula -(Y)fZ 1 , where Y is a connecting arm, f is an integer equal to 0 or 1, and Z 1 is chosen from CN, SCN, NCS, NH2, NR 16 '(C=O)R 16 in which the radicals R 16 and R 16 ', independently of each other, represent a hydrogen atom or an alkyl radical, and a cyclic dithioacetal radical of the following formula:

[0015] [Chem 4] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the carbon of formula (Ul) bearing the R group 1 if f = 0 and at the connecting arm Y if f = 1, and in which R 1 , R 3 and R 4 have the same meaning as that chosen for the R radicals 1 , R 3 and R 4 of the formula (Ul); - when X is an oxygen atom or a sulfur atom, R 3 and R 4 , independently of each other, represent a hydrogen atom, a halogen atom, or a group chosen from an alkyl radical, a haloalkyl radical, an alkylene-phenyl radical possibly substituted, and an alkylene-phenyl radical possibly substituted; - when X is a divalent alkylene radical -(CH2)u- in which u is an integer from 1 to 4, and preferably u is 1, ■ R 3 and R4 , independently of each other, represent a hydrogen atom, a halogen atom, or a group selected from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, and an optionally substituted haloalkylene-phenyl radical; or ■ R 3 represents a hydrogen atom or a halogen atom, and R 4 represents a group of formula -(L) m -Z 2 , where L is a connecting arm, m is an integer equal to 0 or 1, and Z 2 is chosen from an acyl group; phthalimido; P(=O)(OR 17 )(GOLD 17 ') in which the radicals R 17 and R 17 ', independently of each other, represent a hydrogen atom or an alkyl radical; SiR 18 n (GOLD 19 )3-n in which the radicals R 18 and R 19, independently of each other, represent a hydrogen atom or an alkyl radical and n is an integer equal to 0, 1 or 2; BFs / where M = K or Na; B(OR 20 )2 in which the two radicals R 20 Independently of each other, they represent a hydrogen atom, an alkyl radical, or form a carbon ring with the two oxygen atoms to which they are bonded; OR 21 in which R 21 represents a hydrogen atom or an alkyl, aryl, or aralkyl radical; O(C=O)R 22 in which R 22 represents a hydrogen atom or an alkyl, aryl, or aralkyl radical; O(C=O)OR 23 in which R 23 represents a hydrogen atom or an alkyl, aryl, or aralkyl radical; N + R 24 R 24 'R 24 'A' in which the radicals R 24 , R 24 ' and R 24”, independently of each other, represent a hydrogen atom or an alkyl, aryl, or aralkyl radical, and A represents a chlorine or bromine atom; NR 25 '(C=O)R 25 in which the radicals R 25 and R 25 ', independently of each other, represent a hydrogen atom or an alkyl or aryl radical or are linked together and form a ring such as a pyrrolidone or caprolactam ring; NR 26 '(C=O)OR 26 in which R 26 and R 26 ', independently of each other, represent a hydrogen atom or an alkyl, aryl, or aralkyl radical; CN; NCS; SCN; OCH2-epoxy; COOR 27 in which R 27 represents a hydrogen atom, an alkyl, aryl or radical aralkyl; CONR 28 R 28 'in which R 28 and R 28 ', independently of each other, represent a hydrogen atom or an alkyl or aryl radical; SO2R 29 in which R29 represents an alkyl or aryl radical; N3 azide; alkyne; and a cyclic dithioacetal radical with the following formula:

[0016] [Chem 5] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the carbon bearing the R group 3 of the formula (Ul) if m = 0 and to the connecting arm L if m = 1 and in which R 1 , R 2 and R 3 have the same meaning as that chosen for the R radicals 1 , R 2 and R 3 of the formula (Ul), and units of the following formula (II):

[0017] [Chem 6] in which: - R 5 represents a hydrogen atom, or a fluorine atom; - R 6 represents a hydrogen atom, or a fluorine atom; - R 7represents a hydrogen atom, an alkyl radical, a fluorine atom, or a chlorine atom; - R 8 represents a hydrogen atom, or a group chosen from the following groups: ■ an alkyl radical, ■ a haloalkyl radical, ■ an aryl radical, possibly substituted, ■ an alkylene-aryl radical, possibly substituted, ■ an imidazolyl group, ■ an alkylimidazolium group, ■ a carbazoyl group, ■ a group of formula (III) following:

[0018] [Chem 7] in which the symbol (**) represents the anchoring point of the group of formula (III) to the carbon atom of the unit of formula (U-ll), and R 9 and R 10, identical or different, represent a hydrogen atom, an alkyl radical, a possibly substituted alkylene-aryl radical, a possibly substituted aryl radical, a glycidyl group, or R 9 and R 10 together with the nitrogen and carbon atoms of the formula group (III) to which they are linked, form a heterocarbon ring comprising 4 to 7 carbon atoms (including the carbon atom bearing the oxygen atom), ■ a group -OC(O)R 11 , with R 11 representing an alkyl radical, a haloalkyl radical, a possibly substituted alkylene-aryl radical, a possibly substituted aryl radical, ■ a group -C(O)OR 12 , with R 12 representing an alkyl radical, a polyalkyleneglycolalkyl radical, a haloalkyl radical, a possibly substituted alkylene-aryl radical, a possibly substituted aryl radical, ■ a phosphonic acid group (PO(OH)2), ■ a phosphonic acid ester group P(O)(OR 13a )(GOLD 13b ), with R 13a representing a hydrogen atom or an alkyl radical, and R 13b representing an alkyl radical, ■ a sulfonic acid group (SO3H), ■ an ester group of sulfonic acid SO3R 14 , with R 14 representing an alkyl radical or a haloalkyl radical, and ■ an amide group C(O)NR 15a R 15b , with R 15a and R 15b independently of each other, representing a hydrogen atom or an alkyl radical, or together forming an alkyl radical.

[0019] According to the present invention, a degradable or biodegradable polymer is understood to be a polymer whose backbone contains bonds that can be easily broken, in particular by chemical hydrolysis at basic pH (pH > 7) or acidic pH (pH < 7, and preferably at acidic pH), by nucleophilic attack, by enzymatic digestion, by UV irradiation, or by oxidation, to yield smaller and potentially less polluting molecules. According to the invention, said bonds are in particular C-S bonds of dithioacetal groups, and optionally C-S and / or C=S bonds of dithioester groups.

[0020] In the present invention, the copolymer is particularly degradable in the presence of bleach, peroxides such as hydrogen peroxide or benzoyl peroxide, silver nitrate, or exposure to UV, preferably at a wavelength of 254 nm.

[0021] The copolymer of the invention has the advantage of possessing dithioacetal functional groups (a carbon atom bonded to two sulfur atoms and two carbon atoms) that are readily degradable, even biodegradable. In particular, this allows for degradation by oxidation, which is not possible with open units (dithioesters or thioesters).

[0022] Dithioacetal units (Ul)

[0023] X is an oxygen atom or a sulfur atom, or an alkylene divalent radical -(CH2)u-, preferably an oxygen atom or an alkylene divalent radical -(CH2)U-, and particularly preferably an alkylene divalent radical -(CH2)u-.

[0024] Groups R 1 and R 2

[0025] When X is an oxygen atom or a sulfur atom, R 1 and R 2, independently of each other, represent a hydrogen atom, a halogen atom, or a group chosen from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, and an optionally substituted haloalkylene-phenyl radical.

[0026] When X is a divalent alkylene radical -(CH2)u- in which u is an integer from 1 to 4, and preferably u is 1, ■ R 1 and R 2 , independently of each other, represent a hydrogen atom, a halogen atom, or a group selected from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, and an optionally substituted haloalkylene-phenyl radical; or ■ R 1 represents a hydrogen atom or a halogen atom, and R 2 represents a group of formula -(Y)fZ 1, where Y is a connecting arm, f is an integer equal to 0 (connecting arm Y absent) or 1 (connecting arm present), and Z 1 is chosen from CN, -SCN, -NCS, -NH2, NR 16 '(C=O)R 16 in which the radicals R 16 and R 16 ', independently of each other, represent a hydrogen atom or an alkyl radical, and a cyclic dithioacetal radical of the following formula:

[0027] [Chem 8] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the carbon of formula (Ul) bearing the R group 1 if f = 0 and at the connecting arm Y if f = 1, and in which R 1 , R 3 and R 4 have the same meaning as that chosen for the R radicals 1 , R 3 and R 4 of the formula (Ul).

[0028] The halogen atom as group R 1 (respectively R 2) (whatever X) is preferably a fluorine atom.

[0029] The alkyl radical as the R group 1 (respectively R 2 The alkyl radical (for any X) can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear and non-cyclic. The alkyl radical can comprise from 1 to 22 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. An alkyl radical is advantageously a methyl or ethyl group.

[0030] In the invention, the term "halogen alkyl" means an alkyl radical comprising one or more halogen atoms, preferably chosen from chlorine and fluorine atoms. A halogen alkyl may be a perhalogen alkyl, i.e., in which all the hydrogen atoms are replaced by halogen atoms. This replacement may also be partial.

[0031] The haloalkyl radical as the R group1 (respectively R 2 The alkyl radical (for any X) can be linear or branched, cyclic or non-cyclic. The haloalkyl radical is preferably linear and non-cyclic. The haloalkyl radical can comprise from 1 to 18 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. A haloalkyl radical is advantageously a trifluoromethyl, fluoromethyl, chloromethyl, or chloroethyl group.

[0032] An alkylene-phenyl radical possibly substituted as the R group 1 (respectively R 2 ) (whatever X) is a radical comprising at least one (divalent) alkylene radical and at least one possibly substituted phenyl radical which are directly linked by a carbon (of the alkylene radical)-carbon (of the possibly substituted phenyl radical) covalent bond. .

[0033] The alkylene radical of the optionally substituted alkylene-phenyl radical may be linear or branched, cyclic or non-cyclic. The alkylene radical is preferably linear and non-cyclic. The alkylene radical may comprise from 1 to 22 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. An alkylene radical is advantageously a methylene group (-CH2-) or an ethylene group (-CH2-CH2-).

[0034] The possibly substituted alkylene-phenyl radical is linked to the carbon bearing the R group 1 (respectively R 2 ) thanks to the alkylene radical.

[0035] The optionally substituted phenyl group of the optionally substituted alkylene-phenyl radical may be substituted by one or more substituents such as halogen atoms, preferably chosen from chlorine and fluorine atoms, alkyl groups, and haloalkyl groups.

[0036] The haloalkyl radical as a substituent of the phenyl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a trifluoromethyl group.

[0037] The alkyl radical as a substituent of the phenyl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a methyl group.

[0038] The phenyl radical substituted by one or more halogen atoms is preferably a pentafluorinated phenyl radical -CeFs.

[0039] An alkylene-phenyl radical, possibly substituted, is advantageously a benzyl or pentafluorobenzyl radical.

[0040] A haloalkylene-phenyl radical possibly substituted as the R group 1 (respectively R 2) (whatever X) is a radical comprising at least one haloalkylene radical and at least one possibly substituted phenyl radical which are directly linked by a carbon (of the haloalkylene radical)-carbon (of the possibly substituted phenyl radical) covalent bond.

[0041] The haloalkylene radical of the optionally substituted haloalkylene-phenyl radical may be linear or branched, cyclic or non-cyclic. The haloalkylene radical is preferably linear and non-cyclic. It may comprise from 1 to 18 carbon atoms, preferably from 1 to 6, and particularly preferably from 1 to 3. An haloalkylene radical is advantageously a chloromethyl group.

[0042] The possibly substituted haloalkylene-phenyl radical is linked to the carbon bearing the R group 1 (respectively R 2 ) thanks to the haloalkylene radical.

[0043] The optionally substituted phenyl group of the optionally substituted haloalkylene-phenyl radical may be substituted by one or more substituents such as halogen atoms, preferably chosen from chlorine and fluorine atoms, alkyl groups, and haloalkyl groups.

[0044] The haloalkyl radical as a substituent of the phenyl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a trifluoromethyl group.

[0045] The alkyl radical as a substituent of the phenyl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a methyl group.

[0046] The phenyl radical substituted by one or more halogen atoms is preferably a pentafluorinated phenyl radical -CeFs.

[0047] Y-link arm

[0048] The Y-linking arm is preferably a hydrocarbon chain, possibly fluorinated or perfluorinated, in particular a linear, branched or cyclic alkylene chain, possibly fluorinated or perfluorinated.

[0049] According to a preferred embodiment of the invention, the Y-linking arm is a linear, branched, or cyclic alkylene chain having from 1 to 8 carbon atoms, particularly preferably having from 1 to 4 carbon atoms, and more particularly preferably having from 1 to 2 carbon atoms.

[0050] Definition of Z 1

[0051] When Z 1 is NR 16 '(C=O)R 16 , f is preferably equal to 0.

[0052] When Z 1 is CN, -SCN, -NCS, -NH2, f is preferably equal to 0.

[0053] When Z 1 is the cyclic dithioacetal radical, f is preferably equal to 1.

[0054] The radicals R 16 and R16 ', independently of each other, represent a hydrogen atom or an alkyl radical, and preferably R 16 ' represents a hydrogen atom and R 16 represents an alkyl radical.

[0055] The alkyl radical mentioned for R 16 and R 16 The alkyl radical can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear and non-cyclic. The alkyl radical can comprise from 1 to 12 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. Methyl, ethyl, n-propyl, / so-propyl, and n-butyl radicals are particularly preferred.

[0056] Z 1 is preferably a cyclic dithioacetal radical as defined in the invention or NH2.

[0057] Preferred embodiments R 1 and R 2

[0058] When X is an oxygen atom or a sulfur atom, R1 (respectively R 2 ) preferably represents a hydrogen atom or an alkyl radical, particularly preferably a hydrogen atom or an alkyl radical comprising 1 to 3 carbon atoms, and more particularly preferably a hydrogen atom or an alkyl radical comprising 1 or 2 carbon atoms.

[0059] According to a particularly preferred embodiment of the invention: * R 1 = H or CH3, and preferably R 1 = H, * R 2 = H or CH3, and preferably R 2 = H.

[0060] When X is a divalent alkylene radical -(CH2)u- in which u is an integer from 1 to 4, and preferably u is 1, R 1 (respectively R 2) preferably represents a hydrogen atom or an alkyl radical, particularly preferably a hydrogen atom or an alkyl radical comprising 1 to 3 carbon atoms, and more particularly preferably a hydrogen atom or an alkyl radical comprising 1 or 2 carbon atoms; or R 1 preferably represents a hydrogen atom, and R 2 represents a group of formula -(Y)fZ 1 , in which Y is a bonding arm, f is an integer equal to 1 (bonding arm present), Y is a linear alkylene chain having from 1 to 4 carbon atoms, and preferably having from 1 to 2 carbon atoms, and Z 1 is a dithioacetal cyclic radical with the following formula:

[0061] [Chem 9] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the Y-linking arm, and in which R 1 , R 3 and R 4have the same meaning as that chosen for the R radicals 1 , R 3 and R 4 of the formula (Ul).

[0062] According to a particularly preferred embodiment of the invention: * R 1 = H or CH3, and preferably R 1 = H, * R 2 = H or CH3, and preferably R 2 = H.

[0063] Groups R 3 and R 4

[0064] When X is an oxygen atom or a sulfur atom, R 3 , and R 4 , independently of each other, represent a hydrogen atom, a halogen atom, or a group chosen from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, or an optionally substituted haloalkylene-phenyl radical.

[0065] When X is a divalent alkylene radical -(CH2)u- in which u is an integer from 1 to 4, and preferably u is 1, ■ R 3 and R 4 , independently of each other, represent a hydrogen atom, a halogen atom, or a group selected from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, or an optionally substituted haloalkylene-phenyl radical; or ■ R 3 represents a hydrogen atom or a halogen atom, and R 4 represents a group of formula -(L) m -Z 2 , where L is a connecting arm, m is an integer equal to 0 (connecting arm L absent) or 1 (connecting arm L present), and Z 2 is chosen from an acyl group; phthalimido; P(=O)(OR 17 )(GOLD 17 ') in which the radicals R 17 and R 17 ', independently of each other, represent a hydrogen atom or an alkyl radical; SiR 18 n (GOLD 19 )3-n in which the radicals R 18 and R 19, independently of each other, represent a hydrogen atom or an alkyl radical and n is an integer equal to 0, 1 or 2; BFsM + in which M = K or Na; B(OR 20 )2 in which the two radicals R 20 Independently of each other, they represent a hydrogen atom, an alkyl radical, or form a carbon ring with the two oxygen atoms to which they are bonded; OR 21 in which R 21 represents a hydrogen atom or an alkyl, aryl, or aralkyl radical; O(C=O)R 22 in which R 22 represents a hydrogen atom or an alkyl, aryl, or aralkyl radical; O(C=O)OR 23 in which R 23 represents a hydrogen atom or an alkyl, aryl, or aralkyl radical; N + R 24 R 24 'R 24 "A' in which the radicals R 24 , R 24 ' and R 24”, independently of each other, represent a hydrogen atom or an alkyl, aryl, or aralkyl radical, and A represents a chlorine or bromine atom; NR 25 '(C=O)R 25 in which the radicals R 25 and R 25 ', independently of each other, represent a hydrogen atom or an alkyl or aryl radical or are linked together and form a ring such as a pyrrolidone ring or caprolactam; NR 26 '(C=O)OR 26 in which R 26 and R 26 ', independently of each other, represent a hydrogen atom or an alkyl, aryl, or aralkyl radical; CN; NCS; NCS; OCH2-epoxy; COOR 27 in which R 27 represents a hydrogen atom, an alkyl, aryl, or aralkyl radical; CONR 28 R 28 'in which R 28 and R 28 ', independently of each other, represent a hydrogen atom or an alkyl or aryl radical; SO2R 29 in which R29 represents an alkyl or aryl radical; N3 azide; alkyne; and a cyclic dithioacetal radical with the following formula:

[0066] [Chem 10] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the carbon bearing the R group 3 of the formula (Ul) if m = 0 and to the connecting arm L if m = 1 and in which R 1 , R 2 and R 3 have the same meaning as that chosen for the R radicals 1 , R 2 and R 3 of the formula (Ul).

[0067] The halogen atom as group R 3 (respectively R 4 ) (whatever X) is preferably a fluorine atom.

[0068] The alkyl radical as the R group 3 (respectively R 4The alkyl radical (for any X) can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear and non-cyclic. The alkyl radical can comprise from 1 to 22 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. An alkyl radical is advantageously a methyl or ethyl group.

[0069] The haloalkyl radical as the R group 3 (respectively R 4 The alkyl radical (for any X) can be linear or branched, cyclic or non-cyclic. The haloalkyl radical is preferably linear and non-cyclic. The haloalkyl radical can comprise from 1 to 18 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. A haloalkyl radical is advantageously a trifluoromethyl, fluoromethyl, chloromethyl, or chloroethyl group.

[0070] An alkylene-phenyl radical possibly substituted as the R group 3 (respectively R 4 ) (whatever X) is a radical comprising at least one alkylene radical (divalent) and at least one phenyl radical possibly substituted which are directly linked by a carbon (of the alkylene radical)-carbon (of the phenyl radical possibly substituted) covalent bond.

[0071] The alkylene radical of the optionally substituted alkylene-phenyl radical may be linear or branched, cyclic or non-cyclic. The alkylene radical is preferably linear and non-cyclic. The alkylene radical may comprise from 1 to 22 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. An alkylene radical is advantageously a methylene group (-CH2-) or an ethylene group (-CH2-CH2-).

[0072] The radical, possibly substituted, is linked to the carbon bearing the R group. 3 (respectively R 4 ) thanks to the alkylene radical.

[0073] The optionally substituted phenyl group of the optionally substituted alkylene-phenyl radical may be substituted by one or more substituents such as halogen atoms, preferably chosen from chlorine and fluorine atoms, alkyl groups, and haloalkyl groups.

[0074] The haloalkyl radical as a substituent of the phenyl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a trifluoromethyl group.

[0075] The alkyl radical as a substituent of the phenyl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a methyl group.

[0076] The phenyl radical substituted by one or more halogen atoms is preferably a pentafluorinated phenyl radical -CeFs.

[0077] An alkylene-phenyl radical, possibly substituted, is advantageously a benzyl or pentafluorobenzyl radical.

[0078] A haloalkylene-phenyl radical possibly substituted as the R group 3 (respectively R 4 ) (whatever X) is a radical comprising at least one haloalkylene radical and at least one possibly substituted phenyl radical which are directly linked by a carbon (of the haloalkylene radical)-carbon (of the possibly substituted phenyl radical) covalent bond.

[0079] The haloalkylene radical of the optionally substituted haloalkylene-phenyl radical may be linear or branched, cyclic or non-cyclic. The haloalkylene radical is preferably linear and non-cyclic. The haloalkylene radical may comprise from 1 to 18 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. A haloalkylene radical is advantageously a chloromethyl group.

[0080] The possibly substituted haloalkylene-phenyl radical is linked to the carbon bearing the R group 3 (respectively R 4 ) thanks to the haloalkylene radical.

[0081] The optionally substituted phenyl group of the optionally substituted haloalkylene-phenyl radical may be substituted by one or more substituents such as halogen atoms, preferably chosen from chlorine and fluorine atoms, alkyl groups, and haloalkyl groups.

[0082] The haloalkyl radical as a substituent of the phenyl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a trifluoromethyl group.

[0083] The alkyl radical as a substituent of the phenyl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a methyl group.

[0084] The phenyl radical substituted by one or more halogen atoms is preferably a pentafluorinated phenyl radical -CeFs.

[0085] L-shaped connecting arm

[0086] The nature of the L-linking arm is not critical. The L-linking arm may be a hydrocarbon chain possibly fluorinated or perfluorinated, in particular a linear alkylene possibly fluorinated or perfluorinated, which may be interrupted by one or more heteroatoms, preferably by one or more oxygen atoms and, preferably, at least one oxygen atom is in the penultimate position, said hydrocarbon chain possibly fluorinated or perfluorinated having from 1 to 20 carbon atoms, preferably from 1 to 10 carbon atoms, and even more preferably from 1 to 4 carbon atoms.

[0087] According to a particularly preferred embodiment of the invention, the bonding arm L is a linear alkylene chain having from 1 to 8 carbon atoms, and even more preferably from 1 to 4 carbon atoms.

[0088] Definition of Z 2

[0089] The alkyl radical mentioned for R 17 , R17 ', R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 24 ', R 24 ”, R 25 , R 25 R 26 , R 26 ', R 27 , R 28 , R 28 ', and R 29 The alkyl radical can be linear or branched, cyclic or non-cyclic. It is preferably linear and non-cyclic. The alkyl radical can consist of 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms. Methyl, ethyl, n-propyl, / so-propyl, and n-butyl radicals are particularly preferred.

[0090] The Acyle group as Z 2denotes a group of formula -C(=O)-D, in which D denotes a hydrogen atom or a linear or branched hydrocarbon chain, cyclic or non-cyclic, comprising from 1 to 12 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. Among such acyl groups mentioned for Z 2 Examples include formyl, acetyl, propanoyl and pivaloyl groups.

[0091] The aryl radical mentioned for R 21 , R 22 , R 23 , R 24 , R 24 ', R 24 ”, R 25 , R 25 ', R 26 , R 26 ', R 27 , R 28 , R 28 ', and R 29is a monocyclic or polycyclic aromatic hydrocarbon group, possibly mono- or polysubstituted, comprising 3 to 10 carbon atoms, and preferably 5 to 6 carbon atoms. Notable examples include naphthyl, anthranyl, phenantryl, o-tolyl, p-tolyl, xylyl, ethylphenyl, mesityl, and phenyl groups. Among these, the phenyl group is particularly preferred.

[0092] Aryl group substituents

[0093] The aryl radical mentioned for R 21 , R 22 , R 23 , R 24 , R 24 ', R 24 ”, R 25 , R 25 ', R 26 , R 26 ', R 27 , R 28 , R 28 ', and R 29 can thus be substituted by one or more substituents. The substituent(s) can be chosen from halogen atoms such as chlorine and fluorine atoms, alkyl groups, and haloalkyl groups.

[0094] The haloalkyl radical as a substituent of the aryl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a trifluoromethyl group.

[0095] The alkyl radical as a substituent of the aryl radical preferably comprises 1 to 3 carbon atoms. It is advantageously a methyl group.

[0096] The aralkyl radical mentioned for R 21 , R 22 , R 23 , R 24 , R 24 ', R 24 ”, R 26 , R 26 ', and R 27 is a group comprising at least one alkyl radical and at least one aryl radical, said alkyl and aryl radicals being linked by a carbon-carbon bond, and said alkyl and aryl radicals having the same definition as that given for the alkyl and aryl radicals above R 21 , R 22 , R 23 , R 24 , R 24 ', R 24 ”, R 26 , R 26 ', and R 27The benzyl group is a notable example of an aralkyl group. Depending on the radical to which the aralkyl group is attached to the carbon, oxygen, or nitrogen atom on which it is attached, it is referred to as an alkylene-aryl or arylene-alkyl group.

[0097] In P(=O)(OR 17 )(GOLD 17 '), R 17 and R 17 ', independently of each other, preferably represent alkyl radicals.

[0098] In SiR 18 n (GOLD 19 )3-n, preferably, n = 0 and R 19 independently of each other, represent an alkyl radical.

[0099] In B(OR 20 )2, preferably, the two radicals R 20 independently of each other, represent an alkyl radical or form a carbon ring with the two oxygen atoms to which they are bonded.

[0100] In OR 21 , R 21 preferably represents a hydrogen atom or an alkyl radical.

[0101] In O(C=O)R 22 , R 22 preferably represents a hydrogen atom or an alkyl radical.

[0102] In O(C=O)OR 23 , R 23 preferably represents a hydrogen atom or an alkyl radical.

[0103] In N + R 24 R 24 'R 24 "A', the R radicals 24 , R 24 ' and R 24 ", independently of each other, preferably represent an alkyl radical and A represents a chlorine or bromine atom.

[0104] In NR 25 '(C=O)R 25 preferably, R 25 represents an alkyl atom and R 25 ' preferably represents a hydrogen atom or R 25 and R 25 ' are linked together and form a pyrrolidone or caprolactam ring.

[0105] In NR 26 '(C=O)OR 26 preferably, R 26 represents an alkyl atom and R 26' represents a hydrogen atom.

[0106] In COOR 27 , R 27 preferably represents a hydrogen atom or an alkyl radical.

[0107] In CONR 28 R 28 ', R 28 and R 28 ', independently of each other, preferably represent an alkyl radical.

[0108] In SO2R 29 , R 29 preferably represents an alkyl radical.

[0109] According to a particularly preferred embodiment of the invention, Z 2 is chosen from the following groups: - cyano (CN), - phthalimido, - P(=O)(OR 17 )(GOLD 17 '), in particular a dimethylphosphonate group (R 17 = R 17 ' = - CH3) or diethylphosphonate (R 17 = R 17 ' = -CH2CH3) - B(OR 20 )2, - GOLD 21 , - SiR 18 n(OR 19 )3-n, - NR25 '(C=O)R 25 , - NR 26 '(C=O)OR 26 , And - a cyclic dithioacetal radical with the following formula:

[0110] [Chem 11] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the carbon bearing the R group 3 of the formula (Ul) if m = 0 and to the connecting arm L if m = 1 and in which R 1 , R 2 and R 3 have the same meaning as that chosen for the R radicals 1 , R 2 and R 3 of the formula (Ul).

[0111] Preferred embodiments R 3 and R 4

[0112] When X is an oxygen atom or a sulfur atom, R 3 (respectively R 4) preferably represents a hydrogen atom or an alkyl radical, particularly preferably a hydrogen atom or an alkyl radical comprising 1 to 3 carbon atoms, and more particularly preferably a hydrogen atom or an alkyl radical comprising 1 or 2 carbon atoms.

[0113] According to a particularly preferred embodiment of the invention: * R3 = H or CH3 * R4 = H or CH3.

[0114] When X is a divalent alkylene radical -(CH2)u- in which u is an integer from 1 to 4, and preferably u is 1, R 3 (respectively R 4 ) preferably represents a hydrogen atom or an alkyl radical, particularly preferably a hydrogen atom or an alkyl radical comprising 1 to 3 carbon atoms, and more particularly preferably a hydrogen atom or an alkyl radical comprising 1 or 2 carbon atoms; or R 3represents a hydrogen atom and R 4 represents a group of formula -(L) m -Z 2 , in which L is a bonding arm, m is an integer equal to 0 or 1, L is a linear alkylene chain having from 1 to 8 carbon atoms, and preferably having from 1 to 4 carbon atoms, and Z 2 is chosen from: - cyano (CN), - phthalimido, - P(=O)(OR 17 )(GOLD 17 '), in particular a dimethylphosphonate group (R 17 = R 17 ' = - CH3) OR diethylphosphonate - B(OR 20 )2, - GOLD 21 , - SiR 18 n(OR 19 )3-n, - NR 25 '(C=O)R 25 , - NR 26 '(C=O)OR 26 , And - a cyclic dithioacetal radical with the following formula:

[0115] [Chem 12] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the carbon bearing the R group 3 of the formula (Ul) if m = 0 and to the connecting arm L if m = 1 and in which R 1 , R 2 and R 3 have the same meaning as that chosen for the R radicals 1 , R 2 and R 3 of the formula (Ul).

[0116] According to a particularly preferred embodiment of the invention: * R3 = H or CH3 * R4 = H or CH3.

[0117] The dithioacetal unit(s) of formula (Ul) are advantageously chosen from the following dithioacetal units:

[0118] [Tables 1]

[0119] Among these dithioacetal units of formula (Ul-1) to (Ul-11), the dithioacetal units of formulas (Ul-1) to (Ul-3), and (Ul-4) are particularly preferred.

[0120] The units (U-ll)

[0121] R 5 preferably represents a hydrogen atom.

[0122] R 6 preferably represents a hydrogen atom.

[0123] R 7 preferably represents a hydrogen atom or an alkyl radical, and preferably a hydrogen atom.

[0124] The alkyl radical as the R group 7 It can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear and non-cyclic. The alkyl radical can comprise from 1 to 5 carbon atoms, and preferably from 1 to 3 carbon atoms. An alkyl radical is advantageously a methyl group.

[0125] The alkyl radical as the R group 8It can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear and non-cyclic. The alkyl radical can have from 1 to 22 carbon atoms, preferably from 1 to 10 carbon atoms, and particularly preferably from 1 to 5 carbon atoms, said alkyl radical being optionally substituted by a hydroxyl radical.

[0126] As examples of alkyl radicals as group R 8 We can mention the radicals methyl, ethyl, isopropyl, n-butyl, 2-butyl, isobutyl, tert-butyl, n-pentyl, iso-pentyl, neo-pentyl, tert-pentyl, 2-methylbutyl, hexyl, n-octyl, iso-octyl, 2-ethyl-1-hexyl, 2,2,4-trimethylpentyl, nonyl, neodecanyl, decyl, dodecyl, octadecyl, behenyl, or cyclohexylmethyl, and preferably the radical methyl or hexyl.

[0127] The haloalkyl radical as the R group 8It can be linear or branched, cyclic or non-cyclic. The haloalkyl radical is preferably linear and non-cyclic. The haloalkyl radical can comprise from 1 to 22 carbon atoms, and preferably from 1 to 5 carbon atoms.

[0128] The aryl radical as the R group 8 may be a monocyclic or polycyclic aromatic hydrocarbon group, possibly substituted by an alkyl radical comprising 1 to 5 carbon atoms, or an alkoxyl radical comprising 1 to 5 carbon atoms.

[0129] As examples of aryl radicals as group R 8 Examples include phenyl, trityl, naphthalenyl, anthracenyl, and pyrenyl radicals. Among these radicals, the phenyl radical is particularly preferred.

[0130] The alkylene-aryl radical possibly substituted as the R group 8is a radical comprising at least one alkylene radical and at least one possibly substituted aryl radical which are directly linked by a carbon (of the alkylene radical)-carbon (of the possibly substituted aryl radical) covalent bond.

[0131] The alkylene radical of the optionally substituted alkylene-aryl radical may be linear or branched, cyclic or non-cyclic. The alkylene radical is preferably linear and non-cyclic. The alkylene radical may consist of 1 to 22 carbon atoms, preferably 1 to 10 carbon atoms, and particularly preferably 1 to 5 carbon atoms, said alkylene radical being optionally substituted by a hydroxyl radical.

[0132] Examples of alkylene radicals include methylene, ethylene, isopropylene, n-butylene, 2-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, neopentylene, tert-pentylene, 2-methylbutylene, hexylene, n-octylene, isooctylene, 2-ethyl-1-hexylene, 2,2,4-trimethylpentylene, nonylene, neodecanylene, decylene, dodecylene, octadecylene, behenylene, or cyclohexylmethylene, and preferably the methylene or hexylene radical.

[0133] The possibly substituted alkylene-aryl radical is linked to the ethylenic function of the unit (U-ll) via the alkylene radical.

[0134] The aryl radical of the optionally substituted alkylene-aryl radical may be a monocyclic or polycyclic aromatic hydrocarbon group, optionally substituted by an alkyl radical comprising 1 to 5 carbon atoms, or an alkoxyl radical comprising 1 to 5 carbon atoms.

[0135] Examples of aryl radicals include phenyl, trityl, naphthalenyl, anthracenyl, and pyrenyl radicals. Among these, the phenyl radical is particularly preferred.

[0136] An alkylene-aryl radical, possibly substituted, is advantageously a benzyl, p-methoxybenzyl, or pentafluorobenzyl radical.

[0137] The alkyl substituent of the alkylimidazolium radical as the R group 8 preferably comprises 1 to 16 carbon atoms, and particularly preferably 1 to 5 carbon atoms. The alkylimidazolium radical as the R group 8 preferably includes a counter-ion chosen from Br, BF4, and PFe'.

[0138] Formula group (III)

[0139] The alkyl radical as the R group 9 and / or R 10It can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear. The alkyl radical can have from 1 to 22 carbon atoms, and preferably from 1 to 5 carbon atoms.

[0140] As examples of alkyl radicals as group R 9 and / or R 10 We can mention the radicals methyl, ethyl, isopropyl, n-butyl, 2-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neo-pentyl, tert-pentyl, 2-methylbutyl, hexyl, n-octyl, iso-octyl, 2-ethyl-1-hexyl, 2,2,4-trimethylpentyl, nonyl, neodecanyl, decyl, dodecyl, octadecyl, behenyl, cyclohexylmethyl, adamantyl, and cyclohexyl. The methyl radical is preferred.

[0141] The aryl radical as the R group 9 and / or R 10may be a monocyclic or polycyclic aromatic hydrocarbon group, possibly substituted by an alkyl radical comprising 1 to 5 carbon atoms, or an alkoxyl radical comprising 1 to 5 carbon atoms.

[0142] As examples of aryl radicals as group R 9 and / or R 10 Examples include phenyl, trityl, naphthalenyl, anthracenyl, and pyrenyl radicals. Among these radicals, the phenyl radical is particularly preferred.

[0143] The alkylene-aryl radical possibly substituted as the R group 9 and / or R 10 is a radical comprising at least one alkylene radical and at least one possibly substituted aryl radical which are directly linked by a carbon (of the alkylene radical)-carbon (of the possibly substituted aryl radical) covalent bond.

[0144] The alkylene radical of the optionally substituted alkylene-aryl radical can be linear or branched, cyclic or non-cyclic. The alkylene radical is preferably linear. The alkylene radical can contain from 1 to 22 carbon atoms, and preferably from 1 to 5 carbon atoms.

[0145] Examples of alkylene radicals include methylene, ethylene, isopropylene, n-butylene, 2-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, neopentylene, tert-pentylene, 2-methylbutylene, hexylene, n-octylene, isooctylene, 2-ethyl-1-hexylene, 2,2,4-trimethylpentylene, nonylene, neodecanylene, decylene, dodecylene, octadecylene, behenylene, cyclohexylmethylene, adamantylene, and cyclohexylene.

[0146] The possibly substituted alkylene-aryl radical is linked to the nitrogen atom of formula (III) for R 9 and to the carboxyl function of formula (III) for R 10 thanks to the alkylene radical.

[0147] The aryl radical of the optionally substituted alkylene-aryl radical may be a monocyclic or polycyclic aromatic hydrocarbon group, optionally substituted by an alkyl radical comprising 1 to 5 carbon atoms, or an alkoxyl radical comprising 1 to 5 carbon atoms.

[0148] Examples of aryl radicals include phenyl, trityl, naphthalenyl, anthracenyl, and pyrenyl radicals. Among these, the phenyl radical is particularly preferred.

[0149] An alkylene-aryl radical, possibly substituted, is advantageously a benzyl radical, or pentafluorobenzyl radical.

[0150] When R 9 and R 10Together with the nitrogen and carbon atoms of the group with formula (III) to which they are bonded, they form a heterocarbon ring, which can notably be a pyrrolidone, piperidone, or caprolactam ring. Pyrrolidone and caprolactam rings are preferred.

[0151] According to a preferred embodiment of the invention, R 9 and R 10 , identical or different, represent a hydrogen atom, an alkyl radical, or R 9 and R 10 together with the nitrogen and carbon atoms of the formula group (III) to which they are linked, form a heterocarbon ring comprising 4 to 7 carbon atoms (including the carbon atom bearing the oxygen atom).

[0152] According to a particularly preferred embodiment, R 9 represents a hydrogen atom or a methyl radical and R 10 represents a methyl radical, or R 9 and R 10together with the nitrogen and carbon atoms of the group of formula (III) to which they are linked, form a pyrrolidone ring or a caprolactam ring.

[0153] Group -OC(O)R 11

[0154] The alkyl radical as the R group 11 It can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear or branched, and non-cyclic. The alkyl radical can have from 1 to 22 carbon atoms, and preferably from 1 to 5 carbon atoms.

[0155] As examples of alkyl radicals as group R 11 We can mention the radicals methyl, ethyl, isopropyl, n-butyl, 2-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 2-methylbutyl, hexyl, Tl n-Octyl, iso-Octyl, 2-ethyl-1-hexyl, 2,2,4-trimethylpentyl, nonyl, neodecanyl, decyl, dodecyl, octadecyl, behenyl, cyclohexylmethyl, adamantyl, and cyclohexyl. Methyl and tert-butyl radicals are preferred.

[0156] The aryl radical as the R group 11 may be a monocyclic or polycyclic aromatic hydrocarbon group, possibly substituted by an alkyl radical comprising 1 to 5 carbon atoms, or an alkoxyl radical comprising 1 to 5 carbon atoms.

[0157] As examples of aryl radicals as group R 11 Examples include phenyl, trityl, naphthalenyl, anthracenyl, and pyrenyl radicals. Among these radicals, the phenyl radical is particularly preferred.

[0158] The alkylene-aryl radical possibly substituted as the R group 11is a radical comprising at least one alkylene radical and at least one possibly substituted aryl radical which are directly linked by a carbon (of the alkylene radical)-carbon (of the possibly substituted aryl radical) covalent bond.

[0159] The alkylene radical of the optionally substituted alkylene-aryl radical can be linear or branched, cyclic or non-cyclic. The alkylene radical is preferably linear and non-cyclic. The alkylene radical can contain from 1 to 22 carbon atoms, and preferably from 1 to 5 carbon atoms.

[0160] As examples of alkylene radicals as R group 11We can mention the radicals methylene, ethylene, isopropylene, n-butylene, 2-butylene, isobutylene, tert-butylene, n-pentylene, iso-pentylene, neo-pentylene, tert-pentylene, 2-methylbutylene, hexylene, n-octylene, iso-octylene, 2-ethyl-1-hexylene, 2,2,4-trimethylpentylene, nonylene, neodecanylene, decylene, dodecylene, octadecylene, behenylene, cyclohexylmethylene, adamantylene, and cyclohexylene.

[0161] The possibly substituted alkylene-aryl radical is linked to the carbon atom of the ester function via the alkylene.

[0162] The aryl radical of the optionally substituted alkylene-aryl radical may be a monocyclic or polycyclic aromatic hydrocarbon group, optionally substituted by an alkyl radical comprising 1 to 5 carbon atoms, or an alkoxyl radical comprising 1 to 5 carbon atoms.

[0163] Examples of aryl radicals include phenyl, trityl, naphthalenyl, anthracenyl, and pyrenyl radicals. Among these, the phenyl radical is particularly preferred.

[0164] An alkylene-aryl radical, possibly substituted, is advantageously a benzyl radical, or pentafluorobenzyl radical.

[0165] The haloalkyl radical as the R group 11 It can be linear or branched, cyclic or non-cyclic. The haloalkyl radical is preferably linear and non-cyclic. The haloalkyl radical can comprise from 1 to 22 carbon atoms, and preferably from 1 to 5 carbon atoms.

[0166] R 11 preferably represents an alkyl radical or an aryl radical possibly substituted, and particularly preferably an alkyl radical.

[0167] Group -C(O)OR 12

[0168] The alkyl radical as the R group 12It can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear and non-cyclic. The alkyl radical can have from 1 to 22 carbon atoms, and preferably from 1 to 5 carbon atoms.

[0169] As examples of alkyl radicals as group R 12 Examples include the methyl, ethyl, isopropyl, n-butyl, 2-butyl, isobutyl, tert-butyl, n-pentyl, iso-pentyl, neo-pentyl, tert-pentyl, 2-methylbutyl, hexyl, n-octyl, iso-octyl, 2-ethyl-1-hexyl, 2,2,4-trimethylpentyl, nonyl, neodecanyl, decyl, dodecyl, octadecyl, behenyl, isobornyl, cyclohexylmethyl, adamantyl, and cyclohexyl radicals. The n-butyl and 2-ethyl-1-hexyl radicals are preferred.

[0170] The polyalkyleneglycolalkyl radical as the R group 12 may be a polyethylene glycolalkyl group with the formula *-(CH2CH2-O) s-alkyl in which s > 1, preferably from 2 to 50, and particularly preferably from 2 to 10, * denotes the anchoring point of the polyethyleneglycolalkyl radical to the oxygen atom of the ester function, and alkyl is as defined for the R group 12 , and preferably an ethyl or methyl radical. One example is the *-(CH2CH2-O)3-ethyl group.

[0171] The aryl radical as the R group 12 may be a monocyclic or polycyclic aromatic hydrocarbon group, possibly substituted by an alkyl radical comprising 1 to 5 carbon atoms, or an alkoxyl radical comprising 1 to 5 carbon atoms.

[0172] As examples of aryl radicals as group R 12 Examples include phenyl, trityl, naphthalenyl, anthracenyl, and pyrenyl radicals. Among these radicals, the phenyl radical is particularly preferred.

[0173] The alkylene-aryl radical possibly substituted as the R group 12 is a radical comprising at least one alkylene radical and at least one possibly substituted aryl radical which are directly linked by a carbon (of the alkylene radical)-carbon (of the possibly substituted aryl radical) covalent bond.

[0174] The alkylene radical of the optionally substituted alkylene-aryl radical can be linear or branched, cyclic or non-cyclic. The alkylene radical is preferably linear and non-cyclic. The alkylene radical can contain from 1 to 22 carbon atoms, and preferably from 1 to 5 carbon atoms.

[0175] Examples of alkylene radicals include methylene, ethylene, isopropylene, n-butylene, 2-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, neopentylene, tert-pentylene, 2-methylbutylene, hexylene, n-octylene, isooctylene, 2-ethyl-1-hexylene, 2,2,4-trimethylpentylene, nonylene, neodecanylene, decylene, dodecylene, octadecylene, behenylene, isobornylene, cyclohexylmethylene, adamantylene, and cyclohexylene.

[0176] The possibly substituted alkylene-aryl radical is linked to the oxygen atom of the ester function via the alkylene.

[0177] The aryl radical of the optionally substituted alkylene-aryl radical may be a monocyclic or polycyclic aromatic hydrocarbon group, optionally substituted by an alkyl radical comprising 1 to 5 carbon atoms, or an alkoxyl radical comprising 1 to 5 carbon atoms.

[0178] Examples of aryl radicals include phenyl, trityl, naphthalenyl, anthracenyl, and pyrenyl radicals. Among these, the phenyl radical is particularly preferred.

[0179] An alkylene-aryl radical, possibly substituted, is advantageously a benzyl radical, or pentafluorobenzyl radical.

[0180] The haloalkyl radical as the R group 12 It can be linear or branched, cyclic or non-cyclic. The haloalkyl radical is preferably linear and non-cyclic. The haloalkyl radical can comprise from 1 to 22 carbon atoms, and preferably from 1 to 5 carbon atoms.

[0181] R 12 preferably represents an alkyl radical or a polyalkyleneglycolalkyl radical, and particularly preferably an alkyl radical such as a methyl, tert-butyl, n-butyl or 2-ethyl-1-hexyl radical.

[0182] Other groups

[0183] The alkyl radical as the R group 13a or R 13b The alkyl radical can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear and non-cyclic. It can comprise from 1 to 22 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. An alkyl radical is advantageously a methyl or ethyl group.

[0184] The alkyl radical as the R group 14 The alkyl radical can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear and non-cyclic. It can comprise from 1 to 22 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. An alkyl radical is advantageously a methyl or ethyl group.

[0185] The haloalkyl radical as the R group 14The haloalkyl radical can be linear or branched, cyclic or non-cyclic. It is preferably linear and non-cyclic. The haloalkyl radical can comprise from 1 to 18 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. An haloalkyl radical is advantageously a trifluoromethyl group.

[0186] The alkyl radical as the R group 15a or R 15b The alkyl radical can be linear or branched, cyclic or non-cyclic. The alkyl radical is preferably linear and non-cyclic. It can comprise from 1 to 22 carbon atoms, preferably from 1 to 6 carbon atoms, and particularly preferably from 1 to 3 carbon atoms. An alkyl radical is advantageously a methyl or ethyl group.

[0187] When the R groups 15a and R 15b together form an alkyl radical, resulting in a nitrogen ring in which R 15a and R15b together form an alkyl radical, in particular comprising 5 carbon atoms (piperidine ring).

[0188] Preferably, and R 15a and R 15b , independently of each other, represent a hydrogen atom or an alkyl radical as defined in the invention, or together form an alkyl radical as defined in the invention, and particularly preferably R 15a represents a hydrogen atom and R 15b represents an alkyl radical such as a methyl or isopropyl radical, or R 15a and R 15b represent alkyl radicals such as methyl radicals.

[0189] According to a particular embodiment, the formula units (U-ll) are chosen from: * units derived from vinyl ester compounds, represented by the following formula (U-ll-1):

[0190] [Chem 13] in which R 11is as defined in the invention, and preferably a methyl or tert-butyl radical, * units derived from α-olefin compounds, represented by the following formula (U-ll-2):

[0191] [Chem 14] (U-ll-2) in which R 7 represents a hydrogen atom or an alkyl radical as defined in the invention, and preferably a hydrogen atom, and R 8 represents a hydrogen atom, an alkyl radical, or an aryl radical possibly substituted as defined in the invention, and preferably a hydrogen atom or a phenyl radical, * units derived from N-vinyl compounds, represented by the following formula (U-ll-3):

[0192] [Chem 15] (U-ll-3) in which R 9 and R 10 are such as defined in the invention, and preferably R 9represents a hydrogen atom and R 10 represents a methyl radical, or R 9 and R 10 , together with the nitrogen and carbon atoms of the group of formula (III) to which they are linked, form, a pyrrolidone ring or a caprolactam ring, * the units resulting from acrylate and alkacrylate compounds, represented by the following formula (U-ll-4):

[0193] [Chem 16] (U-ll-4) in which R 7 represents a hydrogen atom or an alkyl radical as defined in the invention, and preferably a hydrogen atom, and R 12 is as defined in the invention, and preferably represents an alkyl radical as defined in the invention, and even more preferably an n-butyl or 2-ethyl-1-hexyl radical, * the units derived from acrylamides and alkacrylamides compounds, represented by the following formula (U-ll-5):

[0194] [Chem 17] (U-ll-5) in which R 7 represents a hydrogen atom or an alkyl radical as defined in the invention, and preferably a hydrogen atom, and R 15a and R 15b independently of each other, represent a hydrogen atom or an alkyl radical as defined in the invention, or together form an alkyl radical as defined in the invention, and preferably R 15a represents a hydrogen atom and R 15b represents an alkyl radical such as a methyl or isopropyl radical, or R 15a and R 15b represent alkyl radicals such as methyl radicals.

[0195] Among the aforementioned units, those with formulas (U-ll-1), (U-ll-2) and (U-ll-4) are particularly preferred.

[0196] The copolymer may comprise different (U-ll) units due to at least one difference in one of the R groups 5 , R 6 , R 7and R 8 For example, the copolymer may comprise units of the same chemical type but different types (e.g., different (U-ll-i) type units), or units of different chemical types (e.g., (U-ll-i) type units and (U-ll-i) type units). 1 ), such as (U-ll-4) type units and (U-ll-2) type units).

[0197] The copolymer

[0198] The copolymer of the invention comprises (Ul) and (U-ll) units.

[0199] According to one embodiment, the units (Ul) (characteristics of dithioacetal functions) within the copolymer represent from 1 to about 70% by mole, preferably from about 2 to about 50% by mole, even more preferably from about 5 to about 35% by mole, and even more preferably from about 10 to about 20% by mole, relative to the total number of moles of the copolymer.

[0200] The (Ul) and (U-ll) units can be arranged in various triads to obtain copolymers with diverse structural and functional configurations. In these arrangements, (U-ll), denoted as type "A", is the basic structural unit. The (Ul) unit, denoted as type "B", is incorporated into the copolymer. Triads can take forms such as AAA, consisting entirely of (U-ll) units. In AAB configurations, two (U-ll) units are followed by one (Ul) unit. In ABA triads, (U-ll) units alternate with (Ul) units. ABB triads consist of one (U-ll) unit followed by two consecutive (Ul) units, while BBB triads are entirely composed of (Ul) units. Other mixed sequences are possible, such as BAB. The position and ratio of (U-ll) and (Ul) units can be adjusted to obtain unique polymer properties tailored to specific applications.This versatility allows for precise control of the structural and functional characteristics of the polymer.

[0201] The copolymer formed can be statistical, gradient, or block.

[0202] According to a preferred embodiment of the first object of the invention, the copolymer, preferably degradable or biodegradable, is a statistical copolymer (units (Ul) and (U-ll) dispersed randomly in the copolymer).

[0203] According to the invention, the copolymer, preferably degradable or biodegradable, preferably has a number average molar mass (Mn) of about 2000 to 200000 g / mol, more preferably of about 5000 to 100000 g / mol, and even more preferably of about 10000 to 50000 g / mol.

[0204] In the invention, the number-average molar mass (Mn) of the copolymer is determined by size-exclusion chromatography.

[0205] The dispersity according to the current IUPAC terminology (Mw / Mn) of the copolymer, preferably degradable or biodegradable, according to the invention varies preferably from 1.2 to 6, and even more preferably from 1.4 to 4.

[0206] In the invention, the dispersity of the copolymer is determined by size exclusion chromatography.

[0207] The copolymer comprises a main chain. According to the invention, the main chain of the copolymer is understood to be the longest chain of bonds, i.e. without including the bonds of the side substituents.

[0208] The copolymer of the invention has the distinctive feature of directly integrating one or more sulfur atoms (and consequently several CS bonds) into the main chain and one or more rings incorporating at least one other sulfur atom into the side substituents, so as to form dithioacetal functions (see formula unit (Ul)). This structure thus improves the biodegradability of the copolymer.

[0209] The copolymer may also include dithioester functions which are also degradable.

[0210] In this embodiment, the copolymer further comprises one or more of the following units (U-lll):

[0211] [Chem 18] (U-lll) in which R 1 to R 4 are as defined above. These units are optional and are in the minority (if they exist) compared to the units (Ul) within the copolymer.

[0212] By having both types of closed units (dithioacetals, (Ul) units) and open units (dithioesters, (U-lll) units) within the copolymer of the invention, we gain access to various modes of selective degradation of these units (nucleophilic attack -amines- for the dithioesters, oxidation for the dithioacetals).

[0213] The (Ul), (U-ll), and (U-ll) units can be arranged in various triads to obtain copolymers with diverse structural and functional configurations. In these arrangements, the (U-ll) unit, denoted as type "A," is the basic structural unit. The (Ul) and (U-ll) units, denoted as type "B," are incorporated into the copolymer, with a preference for the (Ul) unit. Triads can take forms such as AAA, consisting entirely of (U-ll) units. In AAB configurations, two (U-ll) units are followed by one (Ul) or (U-III) unit, with a preference for the (Ul) unit. In ABA triads, the (U-ll) units alternate with the (Ul) or (U-ll) unit. ABB triads consist of one unit (U-ll) followed by two consecutive units (Ul) or (U-lll), with a preference for the unit (Ul), while BBB triads are entirely composed of units (Ul) or (U-lll), with a preference for the unit (Ul).Other mixed sequences are possible, such as BAB. The position and ratio of the (Ul I), (Ul), and (U-lll) units can be adjusted to obtain unique polymer properties tailored to specific applications. This versatility allows for precise control of the polymer's structural and functional characteristics, with the (Ul) unit offering increased design flexibility.

[0214] The invention also relates to a second object: a process for preparing at least one polydithioacetal copolymer, preferably degradable or biodegradable, said process comprising at least one radical polymerization step of at least one cyclic monomer with at least one monomer having an ethylenic unsaturation, in the presence of a radical polymerization initiator, said process being characterized in that: (i) the cyclic monomer is chosen from the dithiolactones of the following formula (I):

[0215] [Chem 19] ( in which X, R 1 , R 2 , R 3 , and R 4 are as defined in the first object of the invention, with the exception of the cyclic dithioacetal radicals R 2 and R 4 of (Ul) which become cyclic dithioester radicals respectively: of the following formula:

[0216] [Chem 20] in which the symbol (**) is the point of attachment of the cyclic dithioester radical with carbon of formula (I) bearing the R group 1 if f = 0 and at the connecting arm Y if f = 1, and in which R 1 , R 3 and R 4 have the same meaning as that chosen for the R radicals 1 , R 3 and R 4 of formula (I), and of the following formula:

[0217] [Chem 21] in which the symbol (**) is the point of attachment of the cyclic dithioester radical to the carbon bearing the R group 3 of formula (I) if m = 0 and to the connecting arm L if m = 1 and in which R 1 , R 2 and R 3 have the same meaning as that chosen for the R radicals 1 , R 2 and R 3 of formula (I), and in that: (ii) the monomer having an ethylenic unsaturation is chosen from the monomers of the following formula (II):

[0218] [Chem 22] in which R 5 , R 6 , R 7 and R 8 are as defined in the first object of the invention.

[0219] The process according to the second object of the invention makes it possible to obtain preferably a copolymer according to the first object of the invention.

[0220] The copolymer obtained according to the process in accordance with the second object of the invention comprises one or more dithioacetal functions.

[0221] Preferences regarding R groups 1 to R 8 indicated in the first object of the invention concerning the units of formulas (Ul) and (U-ll), also apply to the second object of the invention.

[0222] Thanks to this process, it is now possible to access, in a simple way, preferably with good yields, copolymers, preferably degradable or biodegradable, and whose degradability can be easily modulated by modifying the respective proportions of monomers of formula (I) and (H).

[0223] In the process of the invention, rings are directly introduced into the polymer chain via the cyclic monomer (I), thereby enabling the formation within the copolymer of units (Ul) as defined in the first object of the invention, comprising dithioacetal functional groups. The process is therefore carried out, surprisingly, at least partially without ring opening. Furthermore, a fraction of the cyclic monomer (I) can also react by radical polymerization with the ring-opening monomer (II). The copolymer thus obtained then comprises, in addition to monomer (I) units (Ul units), other units with dithioester functional groups (Ul units).

[0224] The copolymer's degradability is therefore due to the presence of dithioacetal groups, and possibly dithioester groups, resulting from the incorporation of monomers of formula (I) into the copolymer backbone. The greater their proportion relative to monomers of formula (II), the higher the copolymer's degradability. Thus, after degradation, the length of the resulting fragments is inversely proportional to the amount of monomers of formula (I) integrated into the polymer backbone. Furthermore, the chemical groups at the ends of the resulting fragments are functional and reactive.Furthermore, the dithioester monomers of formula (I) used in the radical copolymerization reaction according to the process of the invention are readily synthesized using conventional techniques known to those skilled in the art, from non-sulfur precursors such as commercially available lactones or from thiolactone precursors as described in WO2017220925, WO2018134510, or FR3075199. In addition, the monomers (I) exhibit the ability to react with both activated monomers such as styrene, its derivatives, or acrylates, and with non-activated monomers such as vinyl esters. Finally, the monomers of formula (II) are mostly commercially available.

[0225] Modulation of R groups 1 , R 2 , R 3 , and R 4The dithiolactone monomer (I) increases its reactivity towards non-activated monomers (II) such as vinyl ester monomers or towards activated monomers (II) such as acrylate, acrylamides, styrene and derivative monomers etc.

[0226] According to a preferred embodiment, the monomer of formula (I) is advantageously chosen from the following monomers:

[0227] [Tables 2]

[0228] Among these dithiolactone monomers of formula (1-1) to (1-11), the monomers of formulas (1-1), (I-2) and (I-3) are particularly preferred, and the monomers of formulas (1-1) and (I-2) are more particularly preferred.

[0229] According to a particular embodiment, the monomer of formula (II) is chosen from: * vinyl ester type monomers represented by the following formula (11-1):

[0230] [Chem 23] in which R 11 is as defined in the first object of the invention (and also in relation to U-ll-1), * α-olefin type monomers represented by the following formula (II-2):

[0231] [Chem 24] (11-2) in which R 7 represents a hydrogen atom or an alkyl radical as defined in the first object of the invention (and also in relation to U-ll-2), and R 8 represents an alkyl radical or an aryl radical possibly substituted as defined in the first object of the invention (and also in relation to U-ll-2), * the N-vinyl type monomers represented by the following formula (11-3):

[0232] [Chem 25] (11-3) in which R 9 and R 10are such as defined in the first object of the invention (and also in relation to U-ll-3), and * acrylate and alkacrylate type monomers represented by the following formula (II-4):

[0233] [Chem 26] (11-4) in which R 7 represents a hydrogen atom or an alkyl radical as defined in the first object of the invention (and also in relation to U-ll-4), and R 12 is as defined in the first object of the invention, and preferably represents an alkyl radical as defined in the first object of the invention (and also in relation to U-ll-4), * acrylamide-type monomers represented by the following formula (II-5):

[0234] [Chem 27] (11-5) in which R 15a and R 15b, independently of each other, representing a hydrogen atom or an alkyl radical as defined in the first object of the invention (and also in relation to U-ll-5), or together forming an alkyl radical as defined in the first object of the invention (and also in relation to U-ll-5).

[0235] Examples of monomers with formula (11-1) include vinyl acetate, vinyl pivalate, vinyl trifluoroacetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate, and vinyl neodecanoate (R 11 (= C9H19, mixture of isomers), and vinyl trifluorobutyrate. Among these monomers of formula (11-1), vinyl acetate and vinyl pivalate are particularly preferred.

[0236] Examples of monomers with the formula (II-2) include ethylene, octene, and styrene. Styrene and ethylene are particularly preferred.

[0237] Among the monomers of formula (11-3), particular examples include acyclic N-vinyl monomers such as N-vinylformamide, N-vinylacetamide, and N-methyl-N-vinylacetamide, as well as cyclic N-vinyl monomers (when R 9 and R 10 form a heterocarbon ring jointly with the nitrogen and carbon atoms of the formula group (III) to which they are bonded, such as N-vinylpyrrolidone, N-vinylpiperidone, and N-vinylcaprolactam. Among such monomers of formula (II-3), N-vinylacetamide, N-vinylcaprolactam, and N-vinylpyrrolidone are particularly preferred.

[0238] Among the monomers of formula (I I-4), one can in particular mention an alkyl acrylate or methacrylate such as methyl acrylate, n-butyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate or adamantyl methacrylate, or a polyethylene glycolalkyl acrylate whose polyethylene glycolalkyl group has the formula *-(CH2CH2-O) s -alkyl in which s ranges from 2 to 10, * denotes the anchoring point of the polyethylene glycol alkyl group to the oxygen atom of the ester function of the acrylate, and alkyl is ethyl or methyl such as tri(ethylene glycol) ethyl ether acrylate (TEGA). Advantageously, the monomer of formula (II-4) is an alkyl acrylate or methacrylate, and preferably methyl, tert-butyl, n-butyl, or 2-ethyl-1-hexyl acrylate.

[0239] Among the monomers with formula (II-5), we can particularly mention / V; / V-dimethylacrylamide or / V-isopropylacrylamide.

[0240] Among the aforementioned monomers, those of formulas (II-2), (II-4) and (II-5) are particularly preferred.

[0241] The process can employ several monomers of different formula (II), due to at least one difference in one of the R groups 5 , R 6 , R 7 and R 8 . For example, the process may employ monomers (II) of the same chemical type and different (e.g. different (ll-i) monomers), or monomers of different chemical types (e.g. (ll-i) monomers and (ll-i') monomers, such as (II-4) monomers and (II-2) monomers).

[0242] According to the process of the invention, the proportion of monomers of formula (I) can be chosen such that the monomer(s) of formula (I) represent at most 100% by mole relative to the total number of monomers of formulas (I) and (II). In one embodiment, the monomer(s) of formula (I) represent from approximately 1 to 50% by mole, preferably from approximately 2 to 30% by mole, and even more preferably from approximately 5 to 20% by mole, relative to the total number of monomers of formulas (I) and (II). Indeed, when the proportion of monomers of formula (I) is less than 1% by mole, the degradability rate of the polymer is low, which is of little interest compared to non-degradable polymers. When the proportion of monomers of formula (I) is greater than 100% by mole, the radical polymerization process is altered, in particular slowed down.

[0243] For the purposes of the present invention, a radical polymerization initiator is understood to be a chemical species capable of forming free radicals, i.e. radicals possessing one or more unpaired electrons on their outer shell.

[0244] According to the process according to the invention, the radical polymerization initiator can be a chemical initiator or a photoinitiator (e.g. under UV or visible light).

[0245] The chemical initiator is preferably chosen from among organic peroxides and hydroperoxides, azo derivatives, persulfates, and radical-generating redox couples (redox systems).

[0246] Among the organic peroxides and hydroperoxides, the following can be mentioned in particular: dilauroyl peroxide (LPO), β-butyl peroxyacetate, β-butyl peroxybenzoate, β-butyl peroxyoctoate, β-butyl peroxydodecanoate, β-butyl peroxyisobutyrate, β-amyl peroxypyvalate, β-butyl peroxypyvalate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, dicumyl peroxide, dibenzoyl peroxide, potassium peroxydisulfate, sodium peroxydisulfate, ammonium peroxydisulfate, cumene hydroperoxide, and β-butyl hydroperoxide. Of these organic peroxides, LPO and β-butyl hydroperoxide are particularly preferred.

[0247] Among the azo derivatives, we can particularly mention 2,2'-azobis(isobutyronitrile) or AIBN, 2,2'-azobis(2-cyano-2-butane), dimethyl-2,2'-azobisdimethylisobutyrate, 4,4'-azobis-(4-cyanopentanoic acid), 1,1'-azobis-(cyclohexanecarbonitrile), 2-(t-butylazo)-2-cyanopropane, 2,2'-azobis-[2-methyl-N(1,1)-bis(hydroxymethyl)-2-hydroxyethyl]propanamide, 2,2'-azobis-[2-methyl-N-hydroxyethyl]propanamide, 2,2'-azobis-(N,N'-dimethyleneisobutyramidine) dihydrochloride, and dihydrochloride of 2,2'-azobis-(2-amidinopropane), 2,2'-azobis-(N,N'-dimethylene isobutyramine), 2,2'-azobis-(2-methyl-N-[1,1bis-(hydroxymethyl)-2-hydroxyethyl]propionamide), 2,2'-azobis-(2-methyl-N-[1,1-bis-(hydroxymethyl)propionamide], 2,2'-azobis-[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis-(isobutyramide)dihydrate, 2,2'-azobis-(2,2,4-trimethylpentane) and 2,2'-azobis-(2-methylpropane).Among these azo derivatives, 2,2' azobis(isobutyronitrile) is particularly preferred.

[0248] Examples of persulfates include ammonium persulfate and potassium persulfate.

[0249] Redox systems are, for example, chosen from systems containing combinations such as: - mixtures of hydrogen peroxide, dialkyl peroxide, a hydroperoxide, a perester, a percarbonate and similar compounds and an iron salt, a titanium salt, zinc formaldehyde sulfoxylate or sodium formaldehyde sulfoxylate, and a reducing sugar, - mixtures of an alkali or ammonium metal persulfate, perborate or perchlorate with an alkali metal bisulfite, such as sodium metabisulfite, and a reducing sugar, and - mixtures of an alkali metal persulfate with an arylphosphinic acid, such as benzenephosphonic acid and others like it, and a reducing sugar.

[0250] Among such redox systems, combinations of ammonium persulfate and sodium formaldehyde sulfoxylate, and tert-butyl hydroperoxide and ascorbic acid are particularly preferred.

[0251] It is also possible to use a photochemical initiator in the ultraviolet (UV) or visible spectrum. Examples of initiators usable in the UV range include 2,2-dimethoxy-2-phenylacetophenone, and benzophenone / amine or benzophenone / alcohol pairs. Thioxanthones are among the initiators usable in the visible spectrum. Finally, certain RAFT control agents such as xanthate or trithiocarbonate can also be used, as they are also good photochemical initiators in both the UV and visible ranges.

[0252] The amount of radical polymerization initiator to be used according to the process according to the present invention is generally determined so that the amount of radicals generated is at most about 5% by mole relative to the total amount of monomers of formulas (I) and (II), and preferably at most about 1% by mole.

[0253] The polymerization step is preferably carried out only in the presence of monomers of formulas (I) and (II) and a radical polymerization initiator, i.e. without a polymerization control agent.

[0254] It is nevertheless possible to implement the polymerization step in the presence of a polymerization control agent, thus allowing access to copolymers, preferably degradable or biodegradable, in block, composition gradient, comb, star-grafted, or hyperbranched forms. Indeed, various controlled radical polymerization processes are known, enabling the production of polymers with controlled architecture and mass. These processes are defined according to the chemical nature of the control agents involved.

[0255] The process of the invention can therefore involve a polymerization control agent.

[0256] The polymerization control agent can be: - a reversible addition-fragmentation chain transfer agent (RAFT), such as a xanthate (MADIX), - an atom transfer radical polymerization (ATRP) agent - an iodine transfer polymerization (ITP) agent, - a reversible chain transfer (RCTP) agent, - an organotellurium compound (in English, "Tellurium-mediated Radical Polymerization" (TERP)), - an organocobalt compound (in English "Cobalt-Mediated radical Polymerization" (CoMP)), or - a control agent for reversible coordination-mediated polymerization (RCMP)).

[0257] A RAFT agent is preferred. One example is methyl 2-(butylthiocarbonothioylthio)propanoate.

[0258] The quantity of control agent to be used according to the process according to the present invention generally varies from 0.2 to 5% by mole about relative to the total quantity of monomers of formulas (I) and (II).

[0259] The radical polymerization step of monomers of formulas (I) and (II) can be carried out in bulk (without solvent) or in solution in at least one solvent, specifically chosen to ensure that the reaction medium remains homogeneous throughout the polymerization reaction. Generally, the solvent is organic, but the use of an aqueous solvent such as water or a mixture of water and a co-solvent is possible if the solubility of the monomer(s) warrants it. The polymerization of monomers of formulas (I) and (II) can also be carried out in a heterogeneous medium, the polymer formed being insoluble in the reaction medium. Polymerization can also be carried out by precipitation, or by dispersion, emulsion, or suspension.

[0260] According to a preferred embodiment of the invention, water, hydroalcoholic mixtures, or organic solvents are used as the reaction medium. Organic solvents are preferred.

[0261] According to one variant, the process is carried out without solvent. Polymerization is then performed in bulk, that is to say without solvent.

[0262] The total amount of polymerizable material in the reaction medium (total amount of monomers of formula (I) and formula (II)) can then be 100%

[0263] According to this first variant, the initiator is preferably an azo derivative as defined above.

[0264] Polymerization is preferably carried out in the presence of monomers of formula (I) and formula (II), the initiator and possibly a RAFT agent.

[0265] According to this first variant, the quantity of initiator used preferably ranges from approximately 0.05% in moles to approximately 5% in moles relative to the total quantity of monomers of formulas (I) and (II).

[0266] According to a second variant, the process is carried out with solvent(s).

[0267] When polymerization is carried out with solvent(s), the total amount of polymerizable material in the reaction medium (total amount of monomers of formula (I) and formula (II)) can vary from about 10% to 90% by mass relative to the total mass of the reaction medium, preferably from about 20% to 80% by mass, and even more preferably from about 30% to 60% relative to the total mass of the reaction medium.

[0268] The solvent may be an organic solvent such as ethyl acetate or an aqueous phase immiscible with the mixture of monomers (I) and (II) or the combination of a hydrophobic additive (liquid alkane) and water.

[0269] In the second case, polymerization is preferably carried out by emulsion, in particular by bringing into contact an aqueous phase comprising at least one surfactant, at least one radical initiator and optionally a buffer (e.g. Na2HPO4), with a mixture of monomers (I) and (II).

[0270] In the third case, polymerization is preferably carried out by miniemulsion, in particular by bringing into contact with water, at least one radical initiator (water-soluble or organo-soluble), a hydrophobic additive (e.g. hexadecane), with a mixture of monomers (I) and (II).

[0271] The inventors have in particular discovered that, unlike state-of-the-art precursors, monomers (I) are capable of being implemented in radical polymerization in dispersed media and in particular in the presence of an aqueous phase.

[0272] According to this second variant, the quantity of initiator used preferably ranges from approximately 0.5% in moles to approximately 7% in moles relative to the total quantity of monomers of formulas (I) and (II).

[0273] According to this second variant, the initiator is preferably a persulfate as defined above.

[0274] The surfactant may be chosen from anionic surfactants such as sodium dodecyl sulfate, nonionic surfactants such as ethoxylated fatty alcohols, cationic surfactants such as cetyltrimethylammonium bromide, and amphoteric surfactants.

[0275] The polymerization step of the process according to the invention can be carried out at a temperature ranging from approximately 5 to 150°C, depending on the nature of the monomers of formulas (I) and (II) used during the reaction. According to a preferred embodiment of the process of the invention, the polymerization step is carried out at a temperature ranging from approximately 20 to 130°C, and even more preferably from approximately 40 to 100°C, and even more preferably from approximately 50 to 90°C.

[0276] The duration of the polymerization step generally varies from 1 to approximately 72 hours, preferably from approximately 2 to 48 hours, more preferably from approximately 3 to 24 hours, and even more preferably from approximately 3 to 20 hours.

[0277] The process of the invention thus makes it possible to produce a copolymer having at least dithioacetal functions which are easily degradable.

[0278] In the process employing a cyclic monomer (I) with at least one monomer containing an ethylenic unsaturation (II) in the presence of a radical polymerization initiator, a fraction of the cyclic monomer (I) may also be consumed during ring-opening polymerization (a secondary reaction). The resulting copolymer then comprises, in addition to dithioacetal groups, dithioester groups. These non-cyclic units (U-1ll) with dithioester groups have the advantage of being susceptible to chemical attack and therefore potentially degradable.

[0279] The degradable copolymers obtained by implementing the process according to the present invention are novel in themselves and as such constitute the third object of the invention.

[0280] The present invention therefore also has as its third object, a polydithioacetal type copolymer, preferably degradable or biodegradable, said copolymer being characterized in that it comprises one or more dithioacetal functions, and that it results from a radical polymerization: (i) of at least one cyclic monomer selected from the following dithiolactones of formula (I):

[0281] [Chem 28] in which X, R 1 , R 2 , R 3 , and R 4 are as defined in the first object of the invention, with the exception of the cyclic dithioacetal radicals R 2 and R 4 which become cyclic dithioester radicals respectively: of the following formula:

[0282] [Chem 29] in which the symbol (**) is the point of attachment of the cyclic dithioester radical to the carbon of formula (I) bearing the R group 1 if f = 0 and at the connecting arm Y if f = 1, and in which R 1 , R 3 and R 4 have the same meaning as that chosen for the R radicals 1 , R 3 and R 4 of formula (I), and of the following formula:

[0283] [Chem 30] in which the symbol (**) is the point of attachment of the cyclic dithioester radical to the carbon bearing the R group 3 of formula (I) if m = 0 and to the connecting arm L if m = 1 and in which R 1 , R 2 and R 3 have the same meaning as that chosen for the R radicals 1 , R 2 and R 3 of formula (I); and (ii) of at least one monomer comprising an ethylenic unsaturation chosen from the following monomers of formula (II):

[0284] [Chem 31] in which R 5 , R 6 , R 7 and R 8 are as defined in the first object of the invention, in the presence of a radical polymerization initiator.

[0285] Preferences regarding R groups 1 to R 8 indicated in the first object of the invention concerning the units of formulas (Ul) and (U-ll), also apply to the third object of the invention.

[0286] According to a particular and preferred embodiment of the invention, said copolymer results from the polymerization of dithiolactone (1-1), (I-2) or (I-3) and styrene, tert-butyl acrylate, or N,N-dimethylacrylamide.

[0287] According to a preferred embodiment of the third object of the invention, the copolymer, preferably degradable or biodegradable, is a statistical copolymer.

[0288] According to the invention, the copolymer, preferably degradable or biodegradable, preferably has an average number molar mass of about 2000 to 200000 g / mol, more preferably about 5000 to 100000 g / mol, and even more preferably about 10000 to 50000 g / mol.

[0289] The dispersity of the polymer, preferably degradable or biodegradable, according to the invention varies preferably from 1.2 to 6, and even more preferably from 1.4 to 4.

[0290] The copolymer may also include dithioester functions which are also degradable.

[0291] According to the invention, the main chain of the copolymer is understood to be the longest chain of bonds, i.e. without including the bonds of the side substituents.

[0292] Thanks to their degradable or biodegradable nature, copolymers according to the present invention can be useful in all types of industries. For example, they can be used in the biomedical field, agriculture, cosmetics, petroleum extraction, detergents, active ingredient release, and packaging.

[0293] The medical field is particularly suitable, especially because the copolymers of the invention, due to their dithioacetal (Ul) units, are sensitive to oxidation, particularly by active oxygen. Active oxygen is a species commonly present in biological mechanisms.

[0294] The invention therefore has as its fourth object the use of a copolymer conforming to the first object or obtained according to a process conforming to the second object of the invention or conforming to the third object of the invention, in the medical field, and in particular for the encapsulation and release of drugs.

[0295] The invention also has as its fifth object the use of at least one dithiolactone corresponding to formula (I) as defined in the second object of the invention as a precursor co-monomer in a radical polymerization.

[0296] Radical polymerization is as defined in the first object of the invention.

[0297] Some dithiolactones corresponding to formula (I) are novel in themselves and constitute a sixth object of the invention.

[0298] The invention thus has as its sixth object a dithiolactone for the implementation of a process as defined in the second object of the invention or for the preparation of a copolymer as defined in the first object of the invention, said dithiolactone corresponding to the following formula (I'):

[0299] [Chem 32] (l> in which: - R 1 , R 2 , R 3 , and R 4 are as defined in the first object of the invention.

[0300] Preferably, the dithiolactone of formula (I') is chosen from the dithiolactones of formulas (1-1) and (I-3) as described in the invention. Brief description of the drawings

[0301] The attached drawing illustrates the invention: [Fig. 1] Figure 1 illustrates the chemical degradation of copolymers according to the invention in the presence of bleach. [Fig. 2] Figure 2 illustrates the chemical degradation of a copolymer according to the invention in the presence of different degradation agents. [Fig. 3] Figure 3 illustrates the chemical degradation of copolymers according to the invention in the presence of bleach. [Fig. 4] Figure 4 illustrates the chemical degradation of copolymers according to the invention in the presence of bleach.

[0302] Other features and advantages of the present invention will become apparent from the description of examples presented below, to which the invention is not, however, limited.

[0303] Examples

[0304] Size exclusion chromatography analyses were performed with an installation equipped with three "Shodex" brand columns ("KF-805" + "KF-804" + "KF-802.5", a refractometric detector and a light scatter detector, for analysis in tetrahydrofuran (THF) at 35°C and a flow rate of 1ml / min.

[0305] For polymers containing / V, / V-dimethylacrylamide (DMA), size exclusion chromatography analyses were performed with a setup equipped with two "Shodex" columns ("KD-804" + "KD-805L"), a refractometric detector and a light scatter detector, for analysis in dimethylformamide (DMF) with lithium bromide (LiBr) (10 mM) at 55°C and a flow rate of 1ml / min.

[0306] In some examples, a dialysis process was performed. This involves using a membrane (in the form of a sealed bag with clips at both ends, immersed in water) with a specific cutoff threshold. This allows the copolymer to remain in the water inside the bag while the lower molecular weight substances filter out to the outside for purification. Dialysis was specifically used for water-soluble copolymers based on DMA or tri(ethylene glycol) ethyl ether acrylate (TEGA).

[0307] Example 1: Synthesis of dithiolactone with formula (1-1)

[0308] First step: synthesis of lactone 1

[0309] [Chem 33] 1

[0310] The procedure is an adaptation of that described in Boyko et al., Synthesis, 2007, 14, 2095-2096.

[0311] A suspension of phosphorus pentoxide (60 g, 0.42 mol) in diethyl ether (Et₂O) (225 mL) was cooled to -20°C, and then ice-cold glycolic acid (15 g, 0.20 mol) in acetone (75 mL) was added dropwise with vigorous stirring. The resulting block of phosphorus pentoxide was stirred with a spatula every 15 to 30 minutes during the 3-hour reaction. The conversion was monitored by NMR. 1 H in DMSO-d6. The resulting solution was filtered and the solvents removed under vacuum. The mixture was extracted with chloroform (CHCh) and dried over magnesium sulfate (MgSCU). The solvent was carefully removed under reduced pressure to obtain a pure, colorless oil with a yield of 60.5% (13.9 g).

[0312] 1 H NMR (300 MHz, CDCI3) ô (ppm): 4.33 (s, 2H, -O-CH2-C(O)O-), 1.58 (s, 6H, -CH3).

[0313] 13C NMR (75 MHz, CDCI3) ô (ppm): 171.5 (-C(O)O-), 112.8 (-OC(CH3)2-O-), 63.6 (-O-CH2-C(O)O-), 25.9 (-CH3).

[0314] 1.2 Second step: synthesis of dithiolactone (1-1)

[0315] [Chem 34] (1-1)

[0316] Lactone 1 as prepared in Example 1.1 (20 g, 0.17 mol), P4S10 (19.2 g, 43.1 mmol), and hexamethyldisiloxane (46.6 g, 0.29 mol) were dissolved in 200 mL of anhydrous toluene. The reaction mixture was then purged with argon for 15 minutes at room temperature and refluxed for 24 hours. The dark mixture was then cooled to room temperature and passed through a silica column (eluent: Et2O / n-pentane 1 / 19 by volume) to remove sulfur impurities. The crude product was then passed through a second silica column with the same eluent. After solvent removal, the crude product was distilled to form an orange oil with an unpleasant odor, yielding 8.2% (2.1 g).

[0317] 1 H NMR (300 MHz, CDCI3) ô (ppm): 4.78 (s, 2H, -O-CH2-C(S)S-), 1.86 (s, 6H, -CH3).

[0318] 13C NMR (75 MHz, CDCI3) ô (ppm): 236.8 (-C(S)S-), 102.6 (-OC(CH3)2-S-), 87.0 (-O-CH2-C(S)S-), 28.8 (-CH3).

[0319] Example 2: Synthesis of a degradable CP1 copolymer based on tert-butyl acrylate and dithionolactone of formula (1-1) according to the process of the invention

[0320] One-eighth mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 32.1 mg (0.22 mmol) of the (1-1) dithiolactone obtained in Example 1, 0.25 g (1.95 mmol) of tetrabutyl acrylate (monomer of formula (11-4)), and 5.6 mg of naphthalene (0.04 mmol) as an internal standard were mixed to form a solution. The (1-1) dithiolactone represents 10 mol% of the total number of moles of tetrabutyl acrylate + dithiolactone (1-1). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 16 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0321] The conversion to monomer was determined by hydrogen nuclear magnetic resonance (NMR) 1H). To do this, the 7.9 ppm signal of naphthalene, used as an internal standard, was integrated as corresponding to 1 and compared to a 4.79 ppm signal corresponding to two hydrogen atoms of dithiolactone (1-1), and then compared with the result of the integral at a reaction time of 0 hours. The conversion of dithiolactone (1-1) after a reaction time of X hours can thus be determined according to the following equation 1:

[0322] [Math 1] >

[0323] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), was 100% for dithiolactone (1-1) and 95% for fe / i-butyl acrylate. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP1 copolymer were measured by size-exclusion chromatography (eluent: tetrahydrofuran THF) with a polymethyl methacrylate (PMMA) calibration curve: Mn = 21500 g / mol; Mw / Mn = 5.1.

[0324] Example 3: Synthesis of a degradable CP2 copolymer based on styrene and dithiolactone of formula (1-1) according to the process of the invention

[0325] 2.9 mg (0.02 mmol) of azobis(isobutyronitrile) (AIBN), 26.2 mg (0.18 mmol) of the (1-1) dithiolactone obtained in Example 1, 0.35 g (3.37 mmol) of styrene (monomer of formula (II-2)), and 9.1 mg of naphthalene (0.07 mmol) as an internal standard were mixed to form a solution. The (1-1) dithiolactone represents 5 mol% of the total number of moles of styrene + (1-1) dithiolactone. The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 48 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0326] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 2, was 84.5% for dithiolactone (1-1) and 86.7% for styrene. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP2 copolymer were measured by size-exclusion chromatography (eluent: THF) with a polystyrene-based (PSt) calibration curve: Mn = 28500 g / mol; Mw / Mn = 2.4.

[0327] Example 4: Synthesis of a degradable CP3 copolymer based on styrene and dithiolactone of formula (1-1) according to the process of the invention

[0328] A solution was formed by mixing 2.2 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 39.5 mg (0.27 mmol) of the (1-1) dithiolactone obtained in Example 1, 0.25 g (2.40 mmol) of styrene (monomer of formula (II-2)), and 6.8 mg (0.05 mmol) of naphthalene as an internal standard. The (1-1) dithiolactone represented 10 mol% of the total moles of styrene and (1-1) dithiolactone. The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 48 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0329] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 2, was 67.0% for dithiolactone (1-1) and 75.4% for styrene. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP3 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 16300 g / mol; Mw / Mn = 2.1.

[0330] Example 5: Synthesis of a degradable CP4 copolymer based on styrene and dithiolactone of formula (1-1) according to the process of the invention

[0331] 2.7 mg (0.02 mmol) of azobis(isobutyronitrile) (AIBN), 96.1 mg (0.65 mmol) of the (1-1) dithiolactone obtained in Example 1, 0.27 g (2.60 mmol) of styrene (monomer of formula (II-2)), and 8.3 mg of naphthalene (0.06 mmol) as an internal standard were mixed to form a solution. The (1-1) dithiolactone represented 20 mol% of the total moles of styrene + (1-1) dithiolactone. The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 48 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0332] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 2, was 42.5% for dithiolactone (1-1) and 54.1% for styrene. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP4 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 9600 g / mol; Mw / Mn = 1.8.

[0333] Example 6: Synthesis of a degradable CP5 copolymer based on tri(ethylene glycol) ethyl ether acrylate and dithiolactone of formula (1-1) by RAFT according to the process of the invention

[0334] 2.0 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 30.2 mg (0.20 mmol) of the (1-1) dithiolactone obtained in Example 1, and 0.4 g were mixed (1.83 mmol) of tri(ethylene glycol) ethyl ether acrylate (monomer of formula (II-4)), 10.3 mg (0.04 mmol) of a RAFT agent (methyl CTA1,2-(butylthiocarbonothioylthio)propanoate), and 5.2 mg of naphthalene (0.04 mmol) as an internal standard, were used to form a solution. Dithiolactone (1-1) represents 10 mol% of the total number of moles of tri(ethylene glycol) ethyl ether acrylate + dithiolactone (1-1). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 16 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0335] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 2, was 83.7% for dithiolactone (1-1) and 88.2% for tri(ethylene glycol) ethyl ether acrylate. Residual monomers were removed by dialysis, and the number-average molar mass (Mn) and dispersity (Mw / Mn) of the CP5 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PMMA-based calibration curve: Mn = 7900 g / mol; Mw / Mn = 1.2.

[0336] Example 7: Synthesis of a degradable CP6 copolymer based on styrene and dithiolactone of formula (1-1) by emulsion polymerization according to the process of the invention

[0337] Sodium dodecyl sulfate (SDS) (0.14 g, 0.49 mmol) and 6 g of a mixture of potassium persulfate (K₂S₂O₈) (5 g, 18.52 mmol) and sodium hydrogen phosphate (Na₂HPO₄) (0.15 g, 1.06 mmol) in H₂O (100 g) were placed in a round-bottom flask and shaken at high speed. A mixture of styrene (1.78 g, 17.12 mmol) (monomer of formula (II-2)) and dithiolactone (1-1) (65.1 mg, 0.44 mmol) was then added. Dithiolactone (1-1) represents 2.5 mol% of the total number of moles of styrene + dithiolactone (1-1). The resulting solution was stirred under a flow of argon for 5 minutes, then placed in an oil bath at 70°C for 3 hours.The reaction mixture was cooled to room temperature, and a small fraction was taken for analysis by dynamic light scattering (DLS), while the remainder of the solution was added to a solution of aluminum sulfate Al₂(SO₄)₃ (0.5 g) in H₂O (5 g). The resulting mixture was filtered, washed several times with water and methanol, and then dried under vacuum.

[0338] The number-average molar mass (Mn) and the dispersity (Mw / Mn) of the CP6 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 17200 g / mol; Mw / Mn = 2.4.

[0339] Example 8: Synthesis of a degradable CP7 copolymer based on te / i-butyl acrylate and dithiolactone of formula (I-2) according to the process of the invention

[0340] In this example, the following dithiolactone with formula (I-2) is used:

[0341] [Chem 35] (1-2)

[0342] It was prepared according to the protocol described in Sheibye et al., Tetrahedron, 1979, 35, 1339-1343.

[0343] A solution was formed by mixing 2.1 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 30.7 mg (0.26 mmol) of dithiolactone (I-2) as shown above, 0.3 g (2.34 mmol) of iron / α-butyl acrylate (monomer of formula (II-4)), and 6.7 mg of naphthalene (0.085 mmol) as an internal standard. Dithiolactone (I-2) represents 10 mol% of the total number of moles of iron / α-butyl acrylate + dithiolactone (I-2). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 16 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0344] The conversion to monomer was determined by hydrogen nuclear magnetic resonance (NMR) 1H). To do this, the 7.9 ppm naphthalene signal, used as an internal standard, was integrated as corresponding to 1 and compared to a 3.64 ppm signal corresponding to two hydrogen atoms of dithiolactone (I-2), and then compared with the result of the integral at a reaction time of 0 hours. The conversion of dithiolactone (I-2) after a reaction time of X hours can thus be determined according to the following equation 1:

[0345] [Math 2]

[0346] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), was 77.3% for dithiolactone (I-2) and 94.5% for te / i-butyl acrylate. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP7 copolymer were measured by size-exclusion chromatography (eluent: tetrahydrofuran THF) with a PMMA-based calibration curve: Mn = 46800 g / mol; Mw / Mn = 2.9.

[0347] Example 9: Synthesis of a degradable CP8 copolymer based on styrene and dithiolactone of formula (I-2) according to the process of the invention

[0348] A solution was formed by mixing 2.6 mg (0.02 mmol) of azobis(isobutyronitrile) (AIBN), 37.8 mg (0.32 mmol) of the dithiolactone (I-2) obtained in Example 8, 0.3 g (2.88 mmol) of styrene (the monomer of formula (I-2)), and 8.2 mg (0.06 mmol) of naphthalene as an internal standard. The dithiolactone (I-2) represented 10 mol% of the total moles of styrene and dithiolactone (I-2). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 48 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0349] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 8, was 24.0% for dithiolactone (I-2) and 92.1% for styrene. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP8 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 16800 g / mol; Mw / Mn = 2.6.

[0350] Example 10: Synthesis of a degradable CP9 copolymer based on styrene and dithiolactone of formula (I-2) according to the process of the invention

[0351] A solution was formed by mixing 2.5 mg (0.02 mmol) of azobis(isobutyronitrile) (AIBN), 70.9 mg (0.60 mmol) of the dithiolactone (I-2) obtained in Example 8, 0.25 g (2.40 mmol) of styrene (monomer of formula (I I-2)), and 7.7 mg (0.06 mmol) of naphthalene as an internal standard. The dithiolactone (I-2) represented 20 mol% of the total number of moles of styrene + dithiolactone (I-2). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 48 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0352] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 8, was 15.2% for dithiolactone (I-2) and 86.9% for styrene. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP9 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 10600 g / mol; Mw / Mn = 2.3.

[0353] Example 11: Synthesis of a degradable CP10 copolymer based on styrene and dithiolactone of formula (I-2) according to the process of the invention

[0354] A solution was formed by mixing 2.1 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 0.12 g (1.03 mmol) of the dithiolactone (I-2) obtained in Example 8, 0.16 g (1.54 mmol) of styrene (monomer of formula (I I-2)), and 6.6 mg of naphthalene (0.05 mmol) as an internal standard. The dithiolactone (I-2) represented 40 mol% of the total number of moles of styrene + dithiolactone (I-2). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 48 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0355] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 8, was 8.5% for dithiolactone (I-2) and 78.4% for styrene. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP10 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 5400 g / mol; Mw / Mn = 2.2.

[0356] Example 12: Synthesis of a degradable CP11 copolymer based on tri(ethylene glycol) ethyl ether acrylate and dithiolactone of formula (I-2) by RAFT according to the process of the invention

[0357] A solution was formed by mixing 2.0 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 24.1 mg (0.20 mmol) of dithiolactone (I-2) obtained in Example 8, 0.4 g (1.83 mmol) of tri(ethylene glycol) ethyl ether acrylate (monomer of formula (I-4)), 10.3 mg (0.04 mmol) of a RAFT agent (CTA1,2-(butylthiocarbonothioylthio)propanoate methyl), and 5.2 mg (0.04 mmol) of naphthalene as an internal standard. Dithiolactone (I-2) represents 10 mol% of the total number of moles of tri(ethylene glycol) ethyl ether acrylate + dithiolactone (I-2). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 16 hours. Polymerization was stopped by rapid cooling. After opening the tube, a portion of the solution was transferred to an NMR tube to determine the conversions.

[0358] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1 H), as explained in example 8, was 45.2% for dithiolactone (I-2) and 97.5% for tri(ethylene glycol) ethyl ether acrylate. Residual monomers were removed by dialysis, and the number-average molar mass (Mn) and dispersity (Mw / Mn) of the CP11 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PMMA-based calibration curve: Mn = 8800 g / mol; Mw / Mn = 1.2.

[0359] Example 13: Synthesis of a degradable CP12 copolymer based on styrene and dithiolactone of formula (I-2) by emulsion polymerization according to the process of the invention

[0360] SDS (0.14 g, 0.49 mmol) and 6 g of a mixture of K₂S₂O₈ (5 g, 18.52 mmol), Na₂HPO₄ (0.15 g, 1.06 mmol) in H₂O (100 g) were placed in a round-bottom flask and shaken at high speed. A mixture of styrene (1.78 g, 17.12 mmol) (monomer of formula (11-2)) and dithiolactone (I-2) (51.9 mg, 0.44 mmol) was then added. Dithiolactone (I-2) represents 2.5 mol% of the total number of moles of styrene + dithiolactone (I-2). The resulting solution was shaken under an argon stream for 5 minutes and then placed in an oil bath at 70°C for 3 hours. The reaction mixture was cooled to room temperature, and a small fraction was taken for DLS analysis, while the remainder of the solution was added to a solution of Al₂(SO₄)₃ (0.5 g) in H₂O (5 g). The resulting mixture was filtered, washed several times with water and methanol, and then dried under vacuum.

[0361] The number-average molar mass (Mn) and the dispersity (Mw / Mn) of the CP12 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 11500 g / mol; Mw / Mn = 3.2.

[0362] Example 14: Synthesis of a degradable CP13 copolymer based on / V, / V-dimethylacrylamide (DMA) and dithiolactone of formula (I-2) according to the process of the invention

[0363] A solution was formed by mixing 2.2 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 15.7 mg (0.13 mmol) of dithiolactone (I-2) obtained in Example 8, 0.25 g (2.53 mmol) of DMA (monomer of formula (I-I-5)), 0.25 g of ethyl acetate, and 6.8 mg (0.05 mmol) of naphthalene as an internal standard. Dithiolactone (I-2) constituted 5 mol% of the total number of moles of DMA + dithiolactone (I-2). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 16 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0364] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 8, was 37.7% for dithiolactone (I-2) and 97.4% for DMA. Residual monomers were removed by dialysis and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP13 copolymer were measured by size-exclusion chromatography (eluent: DMF / LiBr) with a PMMA-based calibration curve: Mn = 31500 g / mol; Mw / Mn = 1.9.

[0365] Example 15: Synthesis of a degradable CP14 copolymer based on / V, / V-dimethylacrylamide (DMA) and dithiolactone of formula (I-2) according to the process of the invention

[0366] A solution was formed by mixing 1.4 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 19.9 mg (0.17 mmol) of dithiolactone (I-2) obtained in Example 8, 0.15 g (1.52 mmol) of DMA (monomer of formula (II-5)), 0.15 g of ethyl acetate, and 4.3 mg (0.03 mmol) of naphthalene as an internal standard. Dithiolactone (I-2) constituted 10 mol% of the total number of moles of DMA + dithiolactone (I-2). The solution was transferred to a Carius tube, which was vacuum-sealed after three degassing cycles. The tube was then placed in an oil bath at 70°C for 16 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0367] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 8, was 33.2% for dithiolactone (I-2) and 76.1% for DMA. Residual monomers were removed by dialysis and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP14 copolymer were measured by size-exclusion chromatography (eluent: DMF / LiBr) with a PMMA-based calibration curve: Mn = 22000 g / mol; Mw / Mn = 1.7.

[0368] Example 16: Synthesis of a degradable CP15 copolymer based on / V, / V-dimethylacrylamide (DMA) and dithiolactone of formula (I-2) according to the process of the invention

[0369] One 1.6 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 44.7 mg (0.38 mmol) of dithiolactone (I-2) obtained in Example 8, 0.15 g (1.52 mmol) of DMA (monomer of formula (I-I-5)), 0.15 g of ethyl acetate, and 4.8 mg (0.04 mmol) of naphthalene as an internal standard were mixed to form a solution. Dithiolactone (I-2) constituted 20 mol% of the total number of moles of DMA + dithiolactone (I-2). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 16 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0370] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 8, was 26.4% for dithiolactone (I-2) and 52.7% for DMA. Residual monomers were removed by dialysis and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP15 copolymer were measured by size-exclusion chromatography (eluent: DMF / LiBr) with a PMMA-based calibration curve: Mn = 11800 g / mol; Mw / Mn = 1.5.

[0371] Example 17: Synthesis of dithiolactone with formula (I-3)

[0372] 17.1 First step: synthesis of lactone 2

[0373] [Chem 36] 9

[0374] The procedure is an adaptation of that described in Cairns et al., Polym. Chem., 2017, 8, 2990-2996.

[0375] Glycolic acid (40 g, 0.53 mol), paraformaldehyde (25.3 g, 0.84 mol), and p-toluenesulfonic acid (9.1 g, 0.05 mol) were dissolved in acetonitrile (1 L) and refluxed at 85°C in a Dean-Stark apparatus for 24 hours. The reaction mixture was cooled, and the acetonitrile was carefully removed under reduced pressure. The crude mixture was extracted with dichloromethane (DCM), washed with saturated sodium chloride (NaCl) solution, and dried over magnesium sulfate (MgSCU). The solvent was removed under vacuum. A pure product was obtained by column chromatography (eluent: EtOAc / n-pentane gradient of 1 / 15 to 1 / 5 by volume) in the form of a colorless oil (11.8 g, yield of 25.5%).

[0376] 1 H NMR (300 MHz, CDCI3) ô (ppm): 5.52 (s, 2H, -O-CH2-O-), 4.21 (s, 2H, -0-CH2-C(O)O-).

[0377] 13C NMR (75 MHz, CDCI3) ô (ppm): 171.2 (-C(O)O-), 96.1 (-O-CH2-O-), 62.5 (-O-CH2-C(O)O-).

[0378] 17.2 Second step: synthesis of dithiolactone (I-3)

[0379] [Chem 37] (1-3)

[0380] Lactone 2 as prepared in Example 17.1 (17.7 g, 0.20 mol), P4S10 (22.4 g, 0.05 mol), and hexamethyldisiloxane (54.4 g, 0.33 mol) were dissolved in 180 mL of anhydrous toluene. The reaction mixture was then purged with argon for 15 minutes at room temperature and refluxed for 24 hours. The dark mixture was then cooled to room temperature and passed through a silica column (eluent: Et2O / n-pentane 1 / 19 by volume) to remove sulfur impurities. The crude product was then passed through a second silica column with the same eluent. After solvent removal, the crude product was distilled to form an orange oil with an unpleasant odor, yielding 2.7% (0.65 g).

[0381] 1 H NMR (300 MHz, CDCI3) ô (ppm): 5.72 (s, 2H, -O-CH2-S-), 4.55 (s, 2H, -O-CH2-C(S)S-).

[0382] 13C NMR (75 MHz, CDCI3) ô (ppm): 235.7 (-C(S)S-), 87.6 (-O-CH2-S-), 80.1 (-O-CH2-C(S)S-).

[0383] Example 18: Synthesis of a degradable CP16 copolymer based on te / i-butyl acrylate and dithiolactone of formula (I-3) according to the process of the invention

[0384] One 1.8 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 26.0 mg (0.22 mmol) of dithiolactone (I-3) obtained in Example 17, 0.25 g (1.95 mmol) of δ / ε-butyl acrylate (monomer of formula (I-I-4)), and 5.6 mg of naphthalene (0.04 mmol) as an internal standard were mixed to form a solution. Dithiolactone (I-3) represents 10 mol% of the total number of moles of δ / ε-butyl acrylate + dithiolactone (I-3). The solution was transferred to a Carius tube, which was sealed under vacuum after three degassing cycles. The tube was then placed in an oil bath at 70°C for 16 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0385] The conversion to monomer was determined by hydrogen nuclear magnetic resonance (NMR) 1H). To do this, the signal at 7.9 ppm of naphthalene, used as an internal standard, was integrated as corresponding to 1 and compared to a signal at 4.55 ppm, corresponding to two hydrogen atoms of dithiolactone (I-3), and then compared with the result of the integral at a reaction time of 0 hours. The conversion of dithiolactone (I-3) after a reaction time of X hours can thus be determined according to the following equation 1:

[0386] [Math 3] 3 7 (i- 3)(i6h) Conversion (I — 3) = 1 — J 4.53 (I - 3)(0 h)

[0387] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), was 100% for dithiolactone (I-3) and 99% for te / i-butyl acrylate. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP16 copolymer were measured by size-exclusion chromatography (eluent: tetrahydrofuran THF) with a PMMA-based calibration curve: Mn = 36100 g / mol; Mw / Mn = 3.7.

[0388] Example 19: Synthesis of a degradable CP17 copolymer based on styrene and dithiolactone of formula (I-3) according to the process of the invention

[0389] A solution was formed by mixing 2.2 mg (0.01 mmol) of azobis(isobutyronitrile) (AIBN), 32.1 mg (0.27 mmol) of dithiolactone (I-3) obtained in Example 17, 0.25 g (2.40 mmol) of styrene (monomer of formula (I-2)), and 6.8 mg (0.05 mmol) of naphthalene as an internal standard. Dithiolactone (I-3) represents 10 mol% of the total number of moles of styrene + dithiolactone (I-3). The solution was transferred to a Carius tube, which was vacuum-sealed after three degassing cycles. The tube was then placed in an oil bath at 70°C for 48 hours. Polymerization was stopped by rapid cooling. After opening the tube, part of the solution was transferred into an NMR tube to determine the conversions.

[0390] The conversion to monomer, determined by nuclear magnetic resonance of hydrogen (NMR) 1H), as explained in example 18, was 88.4% for dithiolactone (I-3) and 76.8% for styrene. The residual monomers were evaporated and the number-average molar mass (Mn), as well as the dispersity (Mw / Mn) of the CP17 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 15500 g / mol; Mw / Mn = 2.3.

[0391] Example 20: Chemical degradation of a degradable CP1 copolymer based on te / i-butyl acrylate and dithiolactone of formula (1-1)

[0392] 10 mg of the CP1 copolymer as prepared in Example 2 were diluted in 1 mL of THF, and 1 mL of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 2600 g / mol, Mw / Mn = 4.2).

[0393] It appears that after degradation of the CP1 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 21500 g / mol, Mw / Mn = 5.1), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0394] Example 21: Chemical degradations of degradable copolymers CP2, CP3, and CP4 based on styrene and dithiolactone of formula (1-1)

[0395] Ten mg of the CP2, CP3, and CP4 copolymers prepared in Examples 3, 4, and 5, respectively, were diluted in 1 mL of THF, and 1 mL of a bleach solution (aqueous NaCl solution containing 11–15% active chlorine, according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixtures were kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography.

[0396] Figure 1 shows the behavior of copolymers CP2, CP3, and CP4 in relative value An (i.e., difference between the refractive index of the analyzed sample and that of the solvent) as a function of retention time (in min) before contact with bleach (CP2: Mn = 28500 g / mol, Mw / Mn = 2.4, Figure 1a; CP3: Mn = 16300 g / mol, Mw / Mn = 2.1, figure 1c; CP4: Mn = 9600 g / mol, Mw / Mn = 1.8, figure 1e); and residues obtained after contacting the copolymers CP2, CP3, and CP4 with bleach (CP2: Mn = 2800 g / mol, Mw / Mn = 1.8, figure 1b; CP3: Mn = 2400 g / mol, Mw / Mn = 1.7, figure 1 d; CP4: Mn = 1500 g / mol, Mw / Mn = 1.3, figure 1 f).

[0397] It appears that after degradation of the CP2, CP3, and CP4 copolymers by bleach, the molar mass distributions are strongly shifted in the low molar mass range compared to the pre-treatment copolymers, attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0398] Example 22: Chemical degradations of a degradable CP2 copolymer based on styrene and dithiolactone of formula (1-1)

[0399] 10 mg of the CP2 copolymer as prepared in Example 3 were diluted in 1 ml of THF, and then a solution of 30 mg of silver nitrate (AgNOs) in 1 ml of water was added. The resulting mixture was kept under stirring in a sealed tube for 7 days at room temperature. The solvent was evaporated under reduced pressure, and then the residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 5800 g / mol, Mw / Mn = 1.5).

[0400] 10 mg of the CP2 copolymer as prepared in Example 3 were diluted in 1 ml of THF, and then 40 mg of benzoyl peroxide (BZ2O2) were added. The resulting mixture was kept under stirring in a sealed tube for 30 days at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 4100 g / mol, Mw / Mn = 1.9).

[0401] 10 mg of the CP2 copolymer as prepared in Example 3 were diluted in 1 mL of THF, and then 1 mL of hydrogen peroxide (H2O2) (3 wt%) was added. The resulting mixture was kept under stirring in a sealed tube for 30 days at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 3700 g / mol, Mw / Mn = 2.0).

[0402] Figure 2 shows the behavior of the CP2 copolymer in relative value An (i.e. difference between the refractive index of the analyzed sample and that of the solvent) as a function of the retention time (in min) before contact with degradation agents AgNOs, BZ2O2 and H2O2 (Figure 2a) and of the residue obtained after contact of the CP2 copolymer with AgNOs (Figure 2b), BZ2O2 (Figure 2c) and H2O2 (Figure 2d).

[0403] It appears that after degradation of the CP2 copolymer by the various degradation agents, the molar mass distribution is strongly shifted towards the low molar mass range compared to the pre-treatment copolymer, attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0404] Example 23: Chemical degradation of a degradable CP5 copolymer based on tri(ethylene glycol) ethyl ether acrylate and dithiolactone of formula (1-1)

[0405] 10 mg of the CP5 copolymer as prepared in Example 6 were diluted in 1 ml of THF, and 1 ml of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 2500 g / mol, Mw / Mn = 1.3).

[0406] It appears that after degradation of the CP5 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 7900 g / mol, Mw / Mn = 1.2), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0407] Example 24: Photochemical degradation of a degradable CP5 copolymer based on tri(ethylenic glycol) ethyl ether acrylate and dithiolactone of formula (1-1)

[0408] 15 mg of the CP5 copolymer as prepared in Example 6 were diluted in 3 ml of water and irradiated with UV rays having a wavelength of 254 nm for 24 hours. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size exclusion chromatography (Mn = 2000 g / mol, Mw / Mn = 1.8).

[0409] It appears that after degradation of the CP5 copolymer by UV irradiation, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 7900 g / mol, Mw / Mn = 1.2), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0410] Example 25: Chemical degradation of a degradable CP6 copolymer based on styrene and dithiolactone of formula (1-1)

[0411] 10 mg of the CP6 copolymer as prepared in Example 7 were diluted in 1 mL of THF, and 1 mL of a bleach solution (aqueous NaCl solution containing 11–15% active chlorine according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 3600 g / mol, Mw / Mn = 2.3).

[0412] It appears that after degradation of the CP6 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 17200 g / mol, Mw / Mn = 2.4), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0413] Example 26: Chemical degradation of a degradable CP7 copolymer based on te / i-butyl acrylate and dithiolactone of formula (I-2)

[0414] 10 mg of the CP7 copolymer as prepared in Example 8 were diluted in 1 ml of THF, and 1 ml of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 3300 g / mol, Mw / Mn = 1.6).

[0415] It appears that after degradation of the CP7 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 46800 g / mol, Mw / Mn = 2.9), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0416] Example 27: Chemical degradations of degradable copolymers CP8, CP9, and CP10 based on styrene and dithiolactone of formula (I-2)

[0417] Ten mg of the CP8, CP9, and CP10 copolymers from Examples 9, 10, and 11, respectively, were diluted in 1 mL of THF, and 1 mL of a bleach solution (aqueous NaCl solution containing 11–15% active chlorine, according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixtures were kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography.

[0418] Figure 3 shows the behavior of copolymers CP8, CP9, and CP10 in relative value An (i.e., difference between the refractive index of the analyzed sample and that of the solvent) as a function of retention time (in min) before contact with bleach (CP8: Mn = 16800 g / mol, Mw / Mn = 2.6, Figure 3a; CP9: Mn = 10600 g / mol, Mw / Mn = 2.3, figure 3c; CP10: Mn = 5400 g / mol, Mw / Mn = 2.2, figure 3e); and residues obtained after contacting the copolymers CP8, CP9, and CP10 with bleach (CP8: Mn = 7900 g / mol, Mw / Mn = 2.5, figure 3b; CP9: Mn = 4700 g / mol, Mw / Mn = 1.6, Figure 3 d; CP10: Mn = 2200 g / mol, Mw / Mn = 1.7, figure 3 f).

[0419] It appears that after degradation of the CP8, CP9, and CP10 copolymers by bleach, the molar mass distributions are strongly shifted in the low molar mass range compared to the pre-treatment copolymers, attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0420] Example 28: Chemical degradation of a degradable CP11 copolymer based on tri(ethyl ether acrylate) and dithiolactone of formula (I-2)

[0421] 10 mg of the CP11 copolymer as prepared in Example 12 were diluted in 1 ml of THF, and 1 ml of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 4000 g / mol, Mw / Mn = 1.4).

[0422] It appears that after degradation of the CP11 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 8800 g / mol, Mw / Mn = 1.2), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0423] Example 29: Photochemical degradation of a degradable CP11 copolymer based on tri(ethylene glycol) ethyl ether acrylate and dithiolactone of formula (I-2)

[0424] 15 mg of the CP11 copolymer as prepared in Example 12 were diluted in 3 ml of water and irradiated with UV rays having a wavelength of 254 nm for 24 hours. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size exclusion chromatography (Mn = 4000 g / mol, Mw / Mn = 2.0).

[0425] It appears that after degradation of the CP11 copolymer by UV irradiation, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 8800 g / mol, Mw / Mn = 1.2), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0426] Example 30: Chemical degradation of a degradable CP12 copolymer based on styrene and dithiolactone of formula (I-2)

[0427] 10 mg of the CP12 copolymer, as prepared in Example 13, were diluted in 1 mL of THF, and 1 mL of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 8200 g / mol, Mw / Mn = 3.6).

[0428] It appears that after degradation of the CP12 copolymer by bleach, the molar mass distribution is shifted into the low molar mass range compared to the pre-treatment copolymer (Mn = 11500 g / mol, Mw / Mn = 3.2), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0429] Example 31: Chemical degradations of degradable copolymers CP13, CP14, and CP15 based on / V, / V-dimethylacrylamide (DMA) and dithiolactone of formula (I-2)

[0430] Ten mg of the CP13, CP14, and CP15 copolymers, as prepared in Examples 14, 15, and 16 respectively, were diluted in 1 mL of DMF / LiBr, and 1 mL of a bleach solution (aqueous NaCl solution containing 11–15% active chlorine, according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixtures were kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in DMF / LiBr and analyzed by size-exclusion chromatography.

[0431] Figure 4 shows the behavior of the copolymers CP13, CP14, and CP15 in relative value An (i.e. difference between the refractive index of the sample analyzed and that of the solvent) as a function of the retention time (in min) before contact with bleach (CP13: Mn = 31500 g / mol, Mw / Mn = 1.9, figure 4 a; CP14: Mn = 22000 g / mol, Mw / Mn = 1.7, figure 4 c; CP15: Mn = 11800 g / mol, Mw / Mn = 1.5, figure 4 e); and residues obtained after contacting the copolymers CP13, CP14, and CP15 with bleach (CP13: Mn = 15700 g / mol, Mw / Mn = 1.5, figure 4 b; CP14: Mn = 12400 g / mol, Mw / Mn = 1.3, figure 4 d; CP15: Mn = 8200 g / mol, Mw / Mn = 1.2, figure 4 f).

[0432] It appears that after degradation of the CP13, CP14, and CP15 copolymers by bleach, the molar mass distributions are strongly shifted in the low molar mass range compared to the pre-treatment copolymers, attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0433] Example 32: Chemical degradations of a degradable CP13 copolymer based on / V ; / V-dimethylacrylamide (DMA) and dithiolactone of formula (I-2)

[0434] 10 mg of the CP13 copolymer as prepared in Example 14 were diluted in 1 ml of water, and then 30 mg of AgNOs was added. The resulting mixture was kept under stirring in a sealed tube for 7 days at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in DMF / LiBr and analyzed by size-exclusion chromatography (Mn = 10500 g / mol, Mw / Mn = 1.4).

[0435] 10 mg of the CP13 copolymer, as prepared in Example 14, were diluted in 2 mL of H2O2 (30 wt%). The resulting mixture was kept under stirring in a sealed tube for 7 days at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in DMF / LiBr and analyzed by size-exclusion chromatography (Mn = 11100 g / mol, Mw / Mn = 1.6).

[0436] It appears that after degradation of the CP13 copolymer by the various degradation agents, the molar mass distribution is strongly shifted towards the low molar mass range compared to the pre-treatment copolymer, attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0437] Example 33: Photochemical degradation of a degradable CP13 copolymer based on / V ; / V-dimethylacrylamide (DMA) and dithiolactone of formula (I-2)

[0438] 15 mg of the CP13 copolymer as prepared in Example 14 were diluted in 3 ml of water and irradiated with UV rays having a wavelength of 254 nm for 24 hours. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size exclusion chromatography (Mn = 12500 g / mol, Mw / Mn = 2.3).

[0439] It appears that after degradation of the CP13 copolymer by UV irradiation, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 8800g / mol, Mw / Mn = 1.2), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0440] Example 34: Chemical degradation of a degradable CP16 copolymer based on te / i-butyl acrylate and dithiolactone of formula (I-3)

[0441] 10 mg of the CP16 copolymer as prepared in Example 18 were diluted in 1 ml of THF, and 1 ml of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 2700 g / mol, Mw / Mn = 7.0).

[0442] It appears that after degradation of the CP16 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 36100 g / mol, Mw / Mn = 3.7), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0443] Example 35: Chemical degradation of a degradable CP17 copolymer based on styrene and dithiolactone of formula (I-3)

[0444] 10 mg of the CP17 copolymer, as prepared in Example 19, were diluted in 1 mL of THF, and 1 mL of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to Thermo Fisher Scientific—Reference 219255000) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 1600 g / mol, Mw / Mn = 1.6).

[0445] It appears that after degradation of the CP17 copolymer by bleach, the molar mass distribution is shifted into the low molar mass range compared to the pre-treatment copolymer (Mn = 15500 g / mol, Mw / Mn = 2.3), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0446] Example 36: Synthesis of dithiolactone with formula (I-4)

[0447] [Chem 38]

[0448] Thiolactone 3-methyl-5-pentyldihydrothiophen-2(3 / - / )-one was prepared according to the procedure described by Langlais et al., Macromolecules 2017, 50, 3524-3531. The thiolactone obtained (0.5 g, 2.69 mmol) and Lawesson's reagent (0.54 g, 1.34 mmol) were dissolved in 5 mL of anhydrous toluene. The reaction mixture was then purged with argon for 15 minutes at room temperature and refluxed for 4 hours. The dark mixture was then cooled to room temperature and passed through a silica column (eluent: Et2O / n-pentane 1 / 19 by volume) to remove sulfur impurities. The crude product was then passed through a second silica column with the same eluent. After solvent removal, the crude product was distilled to form a yellow-orange oil with a yield of 68.1% (0.37 g).

[0449] 1H RMN (600 MHz, CDCI3) ô (ppm) : 3.94 (m, 1 H, -C(S)S-CH-), 3.09 (h, J = 6.9 Hz, 0.5H, -CH-C(S)S-), 2.81 (dp, J = 12.8, 6.5 Hz, 0.5H, -CH-C(S)S-), 2.74 (ddd, J = 12.4, 6.2, 5.0 Hz, 0.5H, -CH2-CH-C(S)S-), 2.35 (dt, J = 12.8, 6.5 Hz, 0.5H, -CH2-CH-C(S)S-), 2.26 (dt, J = 12.8, 6.5 Hz, 0.5H, -CH2-CH-C(S)S-), 1.79 (m, 2H, -C(S)S-CH-CH2-CH2-), 1.72 (m, 0.5H, -CH2-CH-C(S)S-), 1.41 (m, 2H, -C(S)S-CH-CH2-CH2-), 1.35 (dd, J = 7.6, 6.8 Hz, 3H, CH3-CH-C(S)S-), 1.32 (m, 4H, -C(S)S-CH-CH2-CH2-CH2-CH2-), 0.90 (m, 3H, -C(S)S-CH-(CH2)4-CH3).

[0450] 13 C RMN (151 MHz, CDCI3) ô (ppm) : 251 + 250 (-Ç(S)S-), 58 + 58 (ÇH-C(S)S-), 53 + 52 (-C(S)S-ÇH-), 45 + 43 (-ÇH2-CH-C(S)S-), 35 + 35 (-C(S)S-CH-ÇH2-CH2-), 32 + 31 (-C(S)S-CH-CH2-CH2-ÇH2-CH2-), 28 + 28 (-C(S)S-CH-CH2-ÇH2-CH2-), 22 + 22 (-C(S)S-CH-CH2-CH2-CH2-ÇH2-), 20 + 18 (ÇH3-CH-C(S)S-), 14 + 14 (-C(S)S-CH-(CH2)4-ÇH3).

[0451] Example 37: Synthesis of a degradable CP18 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (1-1) by emulsion polymerization according to the process of the invention

[0452] Sodium dodecyl sulfate (SDS) (0.14 g, 0.49 mmol) and 6 g of a mixture of potassium persulfate (K₂S₂O₈) (5 g, 18.52 mmol) and sodium hydrogen phosphate (Na₂HPO₄) (0.15 g, 1.06 mmol) in H₂O (100 g) were placed in a round-bottom flask and shaken at high speed. A mixture of styrene (0.89 g, 8.56 mmol), n-butyl acrylate (1.10 g, 8.56 mmol) (monomer of formula (II-4)), and dithiolactone (1-1) (65.1 mg, 0.44 mmol) was then added. Dithiolactone (1-1) represents 2.5 mol% of the total number of moles of styrene + n-butyl acrylate + dithiolactone (1-1). The resulting solution was stirred under an argon flow for 5 minutes, then placed in an oil bath at 70°C for 3 hours.The reaction mixture was cooled to room temperature, and a small fraction was taken for analysis by dynamic light scattering (DLS), while the remainder of the solution was added to a solution of aluminum sulfate Al₂(SU₄)₃ (0.5 g) in H₂O (5 g). The resulting mixture was filtered, washed several times with water and methanol, and then dried under vacuum.

[0453] The number-average molar mass (Mn) and the dispersity (Mw / Mn) of the CP18 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 30000 g / mol; Mw / Mn = 2.4.

[0454] Example 38: Chemical degradation of a degradable CP18 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (1-1)

[0455] 10 mg of the CP18 copolymer, as prepared in Example 37, were diluted in 1 mL of THF, and 1 mL of a bleach solution (aqueous NaCl solution containing 11–15% active chlorine, according to the Thermo Fisher Scientific supplier) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 4900 g / mol, Mw / Mn = 2.4).

[0456] It appears that after degradation of the CP18 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 30000 g / mol, Mw / Mn = 2.4), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0457] Example 39: Synthesis of a degradable CP19 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (I-2) by emulsion polymerization according to the process of the invention

[0458] Sodium dodecyl sulfate (SDS) (0.14 g, 0.49 mmol) and 6 g of a mixture of potassium persulfate (K2S2O8) (5 g, 18.52 mmol), and sodium hydrogen phosphate (Na2HPO4) (0.15 g, 1.06 mmol) in H2O (100 g) were placed in a round-bottom flask and shaken at high speed. A mixture of styrene (0.89 g, 8.56 mmol) (monomer of formula (I1-2)), n-butyl acrylate (1.10 g, 8.56 mmol) (monomer of formula (11-4)) and dithiolactone (I-2) (51.9 mg, 0.44 mmol) was then added. Dithiolactone (I-2) represents 2.5 mole percent of the total number of moles of styrene + n-butyl acrylate + dithiolactone (I-2). The resulting solution was stirred under an argon flow for 5 minutes, then placed in an oil bath at 70°C for 3 hours.The reaction mixture was cooled to room temperature, and a small fraction was taken for analysis by dynamic light scattering, while the remainder of the solution was added to a solution of aluminum sulfate Al2(SO4)3 (0.5 g) in H2O (5 g). The resulting mixture was filtered, washed several times with water and methanol, and then dried under vacuum.

[0459] The number-average molar mass (Mn) and the dispersity (Mw / Mn) of the CP19 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 12200 g / mol; Mw / Mn = 2.1.

[0460] Example 40: Chemical degradation of a degradable CP19 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (I-2)

[0461] 10 mg of the CP19 copolymer as prepared in Example 39 were diluted in 1 ml of THF and 1 ml of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to the Thermo Fisher Scientific supplier) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 7000 g / mol, Mw / Mn = 2.7).

[0462] It appears that after degradation of the CP19 copolymer by bleach, the molar mass distribution is shifted into the low molar mass range compared to the pre-treatment copolymer (Mn = 12200 g / mol, Mw / Mn = 2.1), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0463] Example 41: Synthesis of a degradable CP20 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (I-2) by mini-emulsion polymerization according to the process of the invention

[0464] An aqueous solution of sodium dodecyl sulfate (SDS) (0.2 g, 0.69 mmol in 6 g of water) was placed in a round-bottom flask and shaken at high speed under a flow of argon for 15 minutes. A mixture of styrene (0.89 g, 8.56 mmol) (monomer of formula (II-2)), n-butyl acrylate (1.10 g, 8.56 mmol) (monomer of formula (11-4)), dithiolactone (I-2) (51.9 mg, 0.44 mmol), and hexadecane (0.1 g, 0.44 mmol) was then rapidly added. Dithiolactone (I-2) represents 2.5 mol% of the total moles of styrene + n-butyl acrylate + dithiolactone (I-2). The resulting solution was stirred for 15 minutes, then placed in a cooled ultrasonic bath (10-15°C) and sonicated for 30 minutes. AIBN (14.1 mg, 0.09 mmol) was then added, and the resulting solution was stirred for 20 minutes, then placed in an oil bath at 70°C for 6 hours.The reaction mixture was cooled to room temperature, and a small fraction was taken for analysis by dynamic light scattering, while the remainder of the solution was added to a solution of aluminum sulfate Al2(SO4)3 (0.5 g) in H2O (5 g). The resulting mixture was filtered, washed several times with water and methanol, and then dried under vacuum.

[0465] The number-average molar mass (Mn) and the dispersity (Mw / Mn) of the CP20 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 74300 g / mol; Mw / Mn = 2.9.

[0466] Example 42: Chemical degradation of a degradable CP20 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (1-2)

[0467] 10 mg of the CP20 copolymer as prepared in Example 41 were diluted in 1 ml of THF, and 1 ml of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to the Thermo Fisher Scientific supplier) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 9500 g / mol, Mw / Mn = 3.0).

[0468] It appears that after degradation of the CP20 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 74300 g / mol; Mw / Mn = 2.9), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0469] Example 43: Synthesis of a degradable CP21 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (I-2) by mini-emulsion polymerization according to the process of the invention

[0470] Sodium dodecyl sulfate (SDS) (0.2 g, 0.69 mmol) dissolved in H2O (6 g) was placed in a round-bottom flask and shaken at high speed under a flow of argon for 15 minutes. A mixture of styrene (0.84 g, 8.05 mmol) (monomer of formula (II-2)), n-butyl acrylate (1.03 g, 8.05 mmol) (monomer of formula (II-4)), dithiolactone (I-2) (0.1 g, 0.85 mmol) and hexadecane (0.1 g, 0.44 mmol) was then added very rapidly. Dithiolactone (I-2) represents 5 mol% of the total number of moles of styrene + n-butyl acrylate + dithiolactone (I-2). The resulting solution was stirred for 15 minutes, then placed in a cooled (10-15°C) ultrasonic bath and sonicated for 30 minutes. Then AIBN (14.1 mg, 0.09 mmol) was added and the resulting solution was stirred for 20 minutes, then placed in an oil bath at 70°C for 6 hours. The reaction mixture was cooled to room temperature and a small fraction was taken for analysis by dynamic light scattering, while the remainder of the solution was poured into an aqueous solution of aluminum sulfate Al2(SO4)3 (0.5 g in 5 g of water). The resulting mixture was filtered, washed several times with water and methanol, and then dried under vacuum.

[0471] The number-average molar mass (Mn) and the dispersity (Mw / Mn) of the CP21 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 38200 g / mol; Mw / Mn = 3.0.

[0472] Example 44: Chemical degradation of a degradable CP21 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (I-2)

[0473] 10 mg of the CP21 copolymer as prepared in Example 43 were diluted in 1 ml of THF, and 1 ml of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to the Thermo Fisher Scientific supplier) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 6000 g / mol, Mw / Mn = 2.6).

[0474] It appears that after degradation of the CP21 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 38200 g / mol; Mw / Mn = 3.0), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

[0475] Example 45: Synthesis of a degradable CP22 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (I-2) by mini-emulsion polymerization according to the process of the invention

[0476] Sodium dodecyl sulfate (SDS) (0.2 g, 0.69 mmol) dissolved in H2O (6 g) was placed in a round-bottom flask and shaken at high speed under a flow of argon for 15 minutes. A mixture of styrene (0.79 g, 7.63 mmol) (monomer of formula (II-2)), n-butyl acrylate (0.98 g, 7.63 mmol) (monomer of formula (II-4)), dithiolactone (I-2) (0.2 g, 1.69 mmol) and hexadecane (0.1 g, 0.44 mmol) was then added very rapidly. Dithiolactone (I-2) represents 10 mol% of the total number of moles of styrene + n-butyl acrylate + dithiolactone (I-2). The resulting solution was stirred for 15 minutes, then placed in a cooled ultrasonic bath (10-15°C) and sonicated for 30 minutes. AIBN (14.1 mg, 0.09 mmol) was then added, and the resulting solution was stirred for 20 minutes, then placed in an oil bath at 70°C for 6 hours. The reaction mixture was cooled to room temperature, and a small fraction was taken for dynamic light scattering analysis, while the remainder of the solution was poured into a solution of aluminum sulfate Al2(SO4)3 (0.5 g) in H2O (5 g). The resulting mixture was filtered, washed several times with water and methanol, and then dried under vacuum.

[0477] The number-average molar mass (Mn) and the dispersity (Mw / Mn) of the CP22 copolymer were measured by size-exclusion chromatography (eluent: THF) with a PSt-based calibration curve: Mn = 27800 g / mol; Mw / Mn = 2.9.

[0478] Example 46: Chemical degradation of a degradable CP22 copolymer based on styrene, n-butyl acrylate and dithiolactone of formula (I-2)

[0479] 10 mg of the CP22 copolymer as prepared in Example 45 were diluted in 1 ml of THF, and 1 ml of a bleach solution (aqueous NaCl solution containing 11-15% active chlorine according to the Thermo Fisher Scientific supplier) was added. The resulting mixture was kept under stirring in a sealed tube for 24 hours at room temperature. The solvent was evaporated under reduced pressure, and the resulting residue was dissolved in THF and analyzed by size-exclusion chromatography (Mn = 5000 g / mol, Mw / Mn = 2.5).

[0480] It appears that after degradation of the CP22 copolymer by bleach, the molar mass distribution is strongly shifted in the low molar mass range compared to the pre-treatment copolymer (Mn = 27800 g / mol; Mw / Mn = 2.9), attesting to the degradation of the skeleton resulting from the presence of the dithioacetal functions.

Claims

Demands

1. A polydithioacetal type copolymer, preferably degradable or biodegradable, comprising one or more dithioacetal units of the following formula (Ul): [Chem 39] (Ul) in which: - X is an oxygen atom, a sulfur atom, or a divalent alkylene radical -(CH2)U in which u is an integer from 1 to 4, - when X is an oxygen atom or a sulfur atom, R 1 and R 2 , independently of each other, represent a hydrogen atom, a halogen atom, or a group chosen from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, and an optionally substituted haloalkylene-phenyl radical, - when X is a divalent alkylene radical -(CH2)u- in which u is an integer from 1 to 4, ■ R 1 and R 2, independently of each other, represent a hydrogen atom, a halogen atom, or a group selected from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, and an optionally substituted haloalkylene-phenyl radical; or ■ R 1 represents a hydrogen atom or a halogen atom, and R 2 represents a group of formula -(Y)fZ 1 , where Y is a connecting arm, f is an integer equal to 0 or 1, and Z 1 is chosen from CN, SCN, NCS, NH2, NR 16 '(C=O)R 16 in which the radicals R 16 and R 16 ', independently of each other, represent a hydrogen atom or an alkyl radical, and a cyclic dithioacetal radical of the following formula: [Chem 40] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the carbon of formula (Ul) bearing the R group 1 if f = 0 and at the connecting arm Y if f = 1, and in which R 1 , R 3 and R 4 have the same meaning as that chosen for the R radicals 1 , R 3 and R 4 of the formula (Ul), - when X is an oxygen atom or a sulfur atom, R 3 and R 4 , independently of each other, represent a hydrogen atom, a halogen atom, or a group chosen from an alkyl radical, a haloalkyl radical, an alkylene-phenyl radical possibly substituted, and an alkylene-phenyl radical possibly substituted; - when X is a divalent alkylene radical -(CH2)u- in which u is an integer from 1 to 4, ■ R 3 and R 4, independently of each other, represent a hydrogen atom, a halogen atom, or a group selected from an alkyl radical, a haloalkyl radical, an optionally substituted alkylene-phenyl radical, and an optionally substituted haloalkylene-phenyl radical; or ■ R 3 represents a hydrogen atom or a halogen atom, and R 4 represents a group of formula -(L) m -Z 2 , where L is a connecting arm, m is an integer equal to 0 or 1, and Z 2 is chosen from an acyl group; phthalimido; P(=O)(OR 17 )(GOLD 17 ') in which the radicals R 17 and R 17 ', independently of each other, represent a hydrogen atom or an alkyl radical; SiR 18 n (GOLD 19 )3-n in which the radicals R 18 and R 19, independently of each other, represent a hydrogen atom or an alkyl radical and n is an integer equal to 0, 1 or 2; BFs / where M = K or Na; B(OR 20 )2 in which the two radicals R 20 Independently of each other, they represent a hydrogen atom, an alkyl radical, or form a carbon ring with the two oxygen atoms to which they are bonded; OR 21 in which R 21 represents a hydrogen atom or an alkyl, aryl, or aralkyl radical; O(C=O)R 22 in which R 22 represents a hydrogen atom or an alkyl, aryl, or aralkyl radical; O(C=O)OR 23 in which R 23 represents a hydrogen atom or an alkyl, aryl, or aralkyl radical; N + R 24 R 24 R 24 HAS - in which the radicals R 24 , R 24 and R 24, independently of each other, represent a hydrogen atom or an alkyl, aryl, or aralkyl radical, and A represents a chlorine or bromine atom; NR 25 '(C=O)R 25 in which the radicals R 25 and R 25 ', independently of each other, represent a hydrogen atom or an alkyl or aryl radical or are linked together and form a ring such as a pyrrolidone or caprolactam ring; NR 26 '(C=O)OR 26 in which R 26 and R 26 ', independently of each other, represent a hydrogen atom or an alkyl, aryl, or aralkyl radical; CN; NCS; NCS; OCH2-epoxy; COOR 27 in which R 27 represents a hydrogen atom, an alkyl, aryl or radical aralkyl; CONR 28 R 28 'in which R 28 and R 28 ', independently of each other, represent a hydrogen atom or an alkyl or aryl radical; SO2R 29 in which R29 represents an alkyl or aryl radical; N3 azide; alkyne; and a cyclic dithioacetal radical with the following formula: [Chem 41] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the carbon bearing the R group 3 of the formula (Ul) if m = 0 and to the connecting arm L if m = 1 and in which R 1 , R 2 and R 3 have the same meaning as that chosen for the R radicals 1 , R 2 and R 3 of the formula (Ul); and units of the following formula (II): [Chem 42] in which: - R 5 represents a hydrogen atom, or a fluorine atom; - R 6 represents a hydrogen atom, or a fluorine atom; - R 7 represents a hydrogen atom, an alkyl radical, a fluorine atom, or a chlorine atom; - R8 represents a hydrogen atom, or a group chosen from the following groups: ■ an alkyl radical, ■ a haloalkyl radical, ■ an aryl radical, possibly substituted, ■ an alkylene-aryl radical, possibly substituted, ■ an imidazolyl group, ■ an alkylimidazolium group, ■ a carbazoyl group, ■ a group of formula (III) following: [Chem 43] in which the symbol (**) represents the anchoring point of the group of formula (III) to the carbon atom of the unit of formula (U-ll), and R 9 and R 10 , identical or different, represent a hydrogen atom, an alkyl radical, a possibly substituted alkylene-aryl radical, a possibly substituted aryl radical, a glycidyl group, or R 9 and R 10together with the nitrogen and carbon atoms of the formula group (III) to which they are linked, form a heterocarbon ring comprising 4 to 7 carbon atoms (including the carbon atom bearing the oxygen atom), ■ a group -OC(O)R 11 , with R 11 representing an alkyl radical, a haloalkyl radical, a possibly substituted alkylene-aryl radical, a possibly substituted aryl radical, ■ a group -C(O)OR 12 , with R 12 representing an alkyl radical, a polyalkyleneglycolalkyl radical, a haloalkyl radical, an alkylene-aryl radical possibly substituted, an aryl radical possibly substituted,■ a phosphonic acid group (PO(OH)2), ■ an ester group of phosphonic acid P(O)(OR 13a )(GOLD 13b ), with R 13a representing a hydrogen atom or an alkyl radical, and R 13b representing an alkyl radical, ■ a sulfonic acid group (SO3H), ■ an ester group of sulfonic acid SO3R 14 , with R 14 representing an alkyl radical or a haloalkyl radical, and ■ an amide group C(O)NR 15a R 15b , with R 15a and R 15b independently of each other, representing a hydrogen atom or an alkyl radical, or together forming an alkyl radical.

2. Copolymer according to claim 1, characterized in that when X is an oxygen atom or a sulfur atom, R 1 and R 2 represent, independently of each other, a hydrogen atom or an alkyl radical comprising 1 to 3 carbon atoms; and when X is a divalent alkylene radical -(CH2)u- in which u is an integer from 1 to 4, R 1 and R 2 represent, independently of each other, a hydrogen atom or an alkyl radical comprising 1 to 3 carbon atoms; or R 1represents a hydrogen atom, and R 2 represents a group of formula -(Y)fZ 1 , where Y is a bonding arm, f is an integer equal to 1, Y is a linear alkylene chain having from 1 to 4 carbon atoms, and Z 1 is a dithioacetal cyclic radical with the following formula: [Chem 44] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the Y-linking arm, and in which R 1 , R 3 and R 4 have the same meaning as that chosen for the R radicals 1 , R 3 and R 4 of the formula (Ul).

3. Copolymer according to claim 1 or 2, characterized in that when X is an oxygen atom or a sulfur atom, R 3 and R 4represent, independently of each other, a hydrogen atom or an alkyl radical comprising from 1 to 3 carbon atoms; and when X is a divalent alkylene radical -(CH2)u- in which u is an integer from 1 to 4, R 3 and R 4 represent, independently of each other, a hydrogen atom or an alkyl radical comprising 1 to 3 carbon atoms; or R 3 represents a hydrogen atom and R 4 represents a group of formula -(L) m -Z 2 , where L is a bonding arm, m is an integer equal to 0 or 1, L is a linear alkylene chain having from 1 to 8 carbon atoms, and Z 2 is chosen from the following groups: - cyano, - phthalimido, - P(=O)(OR 17 )(GOLD 17 '), - B(OR 20 )2, - GOLD 21 , - SiR 18 n(OR 19 )3-n, - NR 25 '(C=O)R 25 , - NR 26 '(C=O)OR 26 , And - a cyclic dithioacetal radical with the following formula: [Chem 45] in which the symbol (**) is the point of attachment of the cyclic dithioacetal radical to the carbon bearing the R group 3 of the formula (Ul) if m = 0 and to the connecting arm L if m = 1 and in which R 1 , R 2 and R 3 have the same meaning as that chosen for the R radicals 1 , R 2 and R 3 of the formula (Ul).

4. Copolymer according to any one of the preceding claims, characterized in that the dithioacetal units of formula (Ul) are selected from the following dithioacetal units: [Tables 3]

5. Copolymer according to any one of the preceding claims, characterized in that X is an oxygen atom or a divalent alkylene radical -(CH2)u-.

6. Copolymer according to any one of the preceding claims, characterized in that the formula units (U-ll) are selected from: * units derived from vinyl ester compounds, represented by the following formula (U-ll-1): [Chem 46] (U-ll-1) in which R 11 is such as defined in claim 1, * units derived from α-olefin compounds, represented by the following formula (U-ll-2): [Chem 47] (U-ll-2) in which R 7 represents a hydrogen atom or an alkyl radical as defined in claim 1, and R 8represents a hydrogen atom, an alkyl radical or an aryl radical, possibly substituted, as defined in claim 1, * units derived from N-vinyl compounds, represented by the following formula (U-ll-3): [Chem 48] (U-ll-3) in which R 9 and R 10 are such as defined in claim 1, * units derived from acrylate and alkacrylate compounds, represented by the following formula (U-ll-4): [Chem 49] (U-ll-4) in which R 7 represents a hydrogen atom or an alkyl radical as defined in claim 1, R 12 is as defined in claim 1, * the units derived from acrylamides and alkacrylamides compounds, represented by the following formula (U-ll-5): [Chem 50] (U-ll-5) in which R 7 represents a hydrogen atom or an alkyl radical as defined in claim 1, and R 15a and R 15b , independently of each other, represent a hydrogen atom or an alkyl radical as defined in claim 1, or together form an alkyl radical as defined in claim 1.

7. Copolymer according to any one of the preceding claims, characterized in that the units (Ul) within the copolymer represent from 1 to 70% by mole, relative to the total number of moles of the copolymer.

8. A process for preparing at least one polydithioacetal copolymer, preferably degradable or biodegradable, as defined in any one of the preceding claims, said process comprising at least one radical polymerization step of at least one cyclic monomer with at least one monomer having an ethylenic unsaturation, in the presence of a radical polymerization initiator, said process being characterized in that: (i) the cyclic monomer is chosen from the dithiolactones of the following formula (I): [Chem 51] W in which X, R 1 , R 2 , R 3 , and R 4 are as defined in any one of claims 1 to 5, with the exception of the cyclic dithioacetal radicals R 2 and R 4 which become cyclic dithioester radicals respectively: of the following formula: [Chem 52] in which the symbol (**) is the point of attachment of the cyclic dithioester radical to the carbon of formula (I) bearing the R group 1 if f = 0 and at the connecting arm Y if f = 1, and in which R 1 , R 3 and R 4 have the same meaning as that chosen for the R radicals 1 , R 3 and R 4 of formula (I), and of the following formula: [Chem 53] in which the symbol (**) is the point of attachment of the cyclic dithioester radical to the carbon bearing the R group 3 of formula (I) if m = 0 and to the connecting arm L if m = 1 and in which R 1 , R 2 and R 3 have the same meaning as that chosen for the R radicals 1 , R 2 and R 3 of formula (I), and in that: (ii) the monomer having an ethylenic unsaturation is chosen from the monomers of the following formula (II): [Chem 54] in which R 5 , R 6 , R 7 and R 8 are as defined in any one of claims 1 or 6.

9. A method according to claim 8, characterized in that the proportion of monomers of formula (I) is chosen such that the monomer(s) of formula (I) represent at most 100% by mole in relation to the total number of monomers of formulas (I) and (II).

10. A process according to claim 8 or 9, characterized in that the radical polymerization step of monomers of formulas (I) and (II) is carried out in bulk or in solution in at least one solvent.

11. A process according to any one of claims 8 to 10, characterized in that the polymerization step is carried out at a temperature ranging from 5 to 150°C.

12. Use of a copolymer as defined in any one of claims 1 to 7 or obtained according to a process as defined in any one of claims 8 to 11, in the medical field.

13. Use of at least one dithiolactone corresponding to formula (I) as defined in claim 8, as a precursor co-monomer in a radical polymerization.

14. Dithiolactone for the preparation of a copolymer as defined in any one of claims 1 to 7 or for the implementation of a process as defined in any one of claims 8 to 11, said dithiolactone corresponding to the following formula (I'): [Chem 55] (0 in which: - R 1 , R 2 , R 3 , and R 4 are as defined in any one of claims 1 to 4.

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