WO2023018326A1

WO2023018326A1 - Synthesis of alkyl triazole glycoside (atg) for oil in water application

Info

Publication number: WO2023018326A1
Application number: PCT/MY2022/050071
Authority: WO
Inventors: Navin Sharma KARAM CHAND; Jofry OTHMAN; Normawati SAMSODIN; Thorsten Heidelberg; Su-Han NG
Original assignee: Petroliam Nasional Bhd Petronas
Current assignee: Petroliam Nasional Bhd Petronas
Priority date: 2021-08-13
Filing date: 2022-08-12
Publication date: 2023-02-16
Anticipated expiration: 2024-02-13
Also published as: MY199508A

Abstract

Provided are compounds of formula (I) and (II), which are useful as surfactants. Also provided are methods of preparing compounds of formula (I) and (II).

Description

SYNTHESIS OF ALKYL TRIAZOLE GLYCOSIDE (ATG) FOR OIL IN WATER APPLICATION FIELD OF THE INVENTION The invention relates to compounds of formula (I) and (II), compositions comprising the compounds, uses of these compounds as surfactants, and to methods for their production. BACKGROUND Carbohydrate based surfactants are an important class of surfactant and are useful in a diverse range of industrial applications, such as: enhanced oil recovery; pharmaceutical products; personal care compositions; and household or industrial cleaning. Carbohydrate based surfactants are bio-sourced, inexpensive, green, nontoxic and may be tailored to a specific use by modifying their morphology. However, the conversion of carbohydrates to surfactants generally results in surfactants that are dominated by the hydrophobic domain. This is due to the constraints of the Fischer glycosylation. While alternative glycosylation reactions exist, they are typically not economic and so are not used on an industrial scale. For example, they typically require acidic reaction conditions and an excess of alcohol, resulting in cleavage of glycosidic bonds in oligosaccharide precursors. The high viscosity of carbohydrate precursors discourages the use of a molar excess of the carbohydrate. These constraints on industrial glycosylation processes result in surfactants that have limited hydrophilicity. The most common class of carbohydrate based surfactants are the alkyl polyglucosides (APGs), which typically have a degree of polymerisation of about 1.5, with a maximum of about 1.8. As a result, the number of sugar units in an APG never reaches 2. However, a higher sugar content would enhance the interaction between the surfactant and water, which would help overcome the dominating hydrophobic behaviour of APGs, which would be favourable for applications such as personal care products and household cleaning products. As such, there is a need for a new class of carbohydrate based surfactants that can be tailored to have dominant hydrophilic or hydrophobic behaviour, especially carbohydrate based surfactants that have increased hydrophilicity as compared to alkyl polyglucosides. There is also a need for carbohydrate based surfactants that may be synthesised easily with high yields without solubility or miscibility issues. SUMMARY OF THE INVENTION The inventors have surprisingly discovered that carbohydrate based surfactants may be quickly and easily prepared from readily available starting materials using an azide-alkyne click chemistry approach. Moreover, a surfactant comprising two sugar moieties arranged in a side-by-side (Y-shaped) configuration (Fig.1(b)) advantageously increases the sugar-water interaction as compared to a surfactant comprising a disaccharide arranged in a linear (series) configuration (Fig. 1(a)). Furthermore, and without being bound by theory, the higher sugar content is believed to be associated with lower skin irritation, which is beneficial in personal care products, pharmaceuticals and domestic cleaning products. The surfactants of the invention (i.e. compounds of formula (I) or (II)) comprise a hydrophobic tail connected to the rest of the molecule (e.g. via an ether linkage). This linkage advantageously allows compounds of formula (I) or (II) to be prepared more quickly, efficiently and economically from simple starting materials obtained from renewable resources, and under more environmentally friendly reaction conditions, as compared to similar molecules that do not comprise an ether linkage in this position. For example, the current invention provides compounds that may be synthesised with fewer chemical steps and without using complex and expensive hydride reductions (e.g of malonic esters to alcohols). The invention provides the following numbered clauses. 1. A compound of formula (I) or (II):

wherein R is selected from the group consisting of a linear or branched C_6-20 alkyl chain, and a linear or branched C_6-20 alkenyl chain that may be mono-, di- or tri-unsaturated; X¹ represents H or –CH₂-Y; X² represents H or –CH₂-Y; provided that for each triazole moiety, one of X¹ and X² is H and the other is -CH₂-Y; each Y is independently selected from the group consisting of a hexose sugar, a pentose sugar, a hexuronic acid, a 2-amino hexose sugar, a disaccharide and an oligosaccharide, where each Y is bonded to the rest of the molecule via an O- glycosidic bond. 2. A compound according to Clause 1, wherein each Y is independently selected from the group consisting of a hexose sugar and a pentose sugar, optionally wherein each Y is a hexose sugar. 3. A compound according to Clause 1 or 2, wherein each Y is independently selected from the group consisting of glucose, mannose, galactose, and xylose, optionally wherein each Y is independently selected from the group consisting of glucose, mannose, and galactose. 4. A compound according to any one of the preceding clauses, wherein each Y is the same. 5. A compound according to any one of the preceding clauses, wherein each Y represents glucose. 6. A compound according to any one of the preceding clauses, wherein R is selected from the group consisting of a linear or branched C_8-16 alkyl chain, and a linear or branched C_8-16 alkenyl chain that may be mono- or di-unsaturated. 7. A compound according to any one of the preceding clauses, wherein R is selected from the group consisting of a linear or branched C_10-14 alkyl chain, and a linear or branched C_10-14 alkenyl chain that may be mono- or di-unsaturated, optionally wherein R represents a C_10-12 linear alkyl chain. 8 A compound according to any one of the preceding clauses, wherein R represents a linear or branched alkyl chain, optionally wherein R represents a linear alkyl chain. 9. A compound according to any one of Clauses 1 to 7, wherein R represents: (a) a moiety formed by removing a hydrogen atom from an acyclic monoterpene; or (b) a moiety formed by removing a hydroxyl group from an acyclic monoterpene alcohol. 10. A compound according to any one of the preceding clauses, wherein each X¹ is the same and each X² is the same. 11. A compound according to any one of the preceding clauses, wherein each X¹ is -CH₂-Y and each X² is H. 12. A compound according to any one of the preceding clauses, which is of formula (I). 13. A compound according to any one of Clauses 1 to 11, which is of formula (II). 14. A compound according to any one of Clauses 1 to 12, which is a compound of formula (I) having the formula (Ia) or (Ib):

15. A compound according to any one of Clauses 1 to 11 or 13, which is a compound of formula (II) having the formula (IIa) or (IIb):

(IIa),

(IIb). 16. A surfactant composition comprising: (i) a compound of formula (I); and/or (ii) a compound of formula (II), wherein the compound of formula (I) and compound of formula (II) are each as defined in any one of the preceding clauses. 17. Use of a compound according to any one of Clauses 1 to 15, or a composition according to Clause 14, as a surfactant. 18. A method of stabilising an oil-in-water emulsion comprising the steps: (a) providing an oil-in-water emulsion; and (b) contacting the oil-in-water emulsion with an effective amount of a compound according to any one of Clauses 1 to 15, or a composition according to Clause 16, so as to stabilise the emulsion. 19. A method of making a compound of formula (I) or (II) according to any one of Clauses 1 to 15, comprising the steps: (i) providing a compound of formula (Ip) or (IIp)

(Ip) (IIp); (ii) reacting the compound of formula (Ip) or (IIp) with a compound of formula (III) in the presence of a metal catalyst

(III) wherein in formula (III), Z represents a sugar moiety as defined for moiety Y in Clause 1, or a protected version thereof (e.g. an acetylated sugar moiety), where said sugar moiety or protected version thereof is bonded to the rest of the molecule via an O-glycosidic bond; and (iii) when Z represents a protected sugar moiety, performing a deprotecting step to provide a compound of formula (I) or (II) in which Y is not a protected sugar, optionally wherein in step (ii), Z represents an unprotected sugar moiety as defined for moiety Y in Clause 1. 20. The method according to Clause 19, wherein the metal catalyst is selected from the group consisting of a Cu(I) catalyst, a Ru(II) catalyst and a Ag(I) catalyst, optionally wherein the metal catalyst is selected from the group consisting of a Cu(I) catalyst, and a Ru(II) catalyst, more optionally wherein the metal catalyst is a Cu(I) catalyst. 21. The method according to Clause 19 or 20, further comprising forming the compound of formula (Ip) by the steps: (a) reacting a compound of formula (IV) with NaN3 to form a compound of formula (Ipp)

(IV) (Ipp); and (b) reacting the compound of formula (Ipp) with a with a compound of formula R-X, where X is a leaving group (such as a halide, e.g. Br), to form a compound of formula (Ip). 22. The method according to Clause 19 or 20, further comprising forming the compound of formula (IIp) by the steps: (a) reacting a compound of formula (V) with a compound of formula R-OH to form a compound of formula (VI)

(V) (VI); (b) reacting the compound of formula (VI) with Cl2 to form a compound of formula (IIpp)

(IIpp); and (c) reacting the compound of formula (IIpp) with NaN3 to form the compound of formula (IIp). BRIEF DESCRIPTION OF THE FIGURES Fig.1 shows two possible configurations for a surfactant comprising two sugar moieties and a hydrophobic tail. (a) shows two sugar moieties in series, while (b) shows two sugar moieties in parallel (Y-shaped surfactant). Fig.2 shows a synthetic route for formation of a compound of formula (Ia). Fig.3 shows a synthetic route for formation of a compound of formula (IIa). Fig. 4 shows the general structure of alkyl polyglucoside (APG) and alkyl triazole glycoside (ATG). DETAILED DESCRIPTION As explained above, the carbohydrate based surfactants of the invention may be quickly and easily prepared from readily available starting materials using an azide-alkyne click chemistry approach. The surfactants of the invention comprise two sugar moieties arranged in a side- by-side (Y-shaped) configuration as shown in Fig.1(b), which advantageously increases the sugar-water interaction, and may be associated with lower skin irritation. The surfactants of the invention (i.e. compounds of formula (I) or (II)) also comprise a hydrophobic tail connected to the rest of the molecule (e.g. via an ether linkage). This linkage advantageously allows compounds of formula (I) or (II) to be prepared by more quickly, efficiently and economically from simple starting materials obtained from renewable resources, and under more environmentally friendly reaction conditions, as compared to similar molecules that do not comprise an ether linkage in this position. Thus, in an aspect of the invention, there is provided a compound of formula (I) or (II):

(I)

(II) wherein R is selected from the group consisting of a linear or branched C_6-20 alkyl chain, and a linear or branched C_6-20 alkenyl chain that may be mono-, di- or tri-unsaturated; X¹ represents H or –CH₂-Y; X² represents H or –CH₂-Y; provided that for each triazole moiety, one of X¹ and X² is H and the other is -CH₂-Y; each Y is independently selected from the group consisting of a hexose sugar, a pentose sugar, a hexuronic acid, a 2-amino hexose sugar, a disaccharide and an oligosaccharide, where each Y is bonded to the rest of the molecule via an O-glycosidic bond. The word “comprising” refers herein may be interpreted as requiring the features mentioned, but not limiting the presence of other features. Alternatively, the word “comprising” may also relate to the situation where only the components/features listed are intended to be present (e.g. the word “comprising” may be replaced by the phrases “consists of” or “consists essentially of”). It is explicitly contemplated that both the broader and narrower interpretations can be applied to all aspects and embodiments of the present invention. In other words, the word “comprising” and synonyms thereof may be replaced by the phrase “consisting of” or the phrase “consists essentially of” or synonyms thereof and vice versa. The phrase, “consists essentially of” and its pseudonyms may be interpreted herein to refer to a material where minor impurities may be present. For example, the material may be greater than or equal to 90% pure, such as greater than 95% pure, such as greater than 97% pure, such as greater than 99% pure, such as greater than 99.9% pure, such as greater than 99.99% pure, such as greater than 99.999% pure, such as 100% pure. As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a composition” includes mixtures of two or more such compositions, reference to “an oxygen carrier” includes mixtures of two or more such oxygen carriers, reference to “the catalyst” includes mixtures of two or more such catalysts, and the like. R may be selected from the group consisting of a linear or branched C_6-20 alkyl chain, and a linear or branched C_6-20 alkenyl chain that may be mono-, di- or tri-unsaturated. Thus, in some embodiments of the invention that may be mentioned herein, R may be a linear or branched C_6-20 alkyl chain, and may optionally be a linear or branched C_8-16 alkyl chain, for example a linear or branched C_10-14 alkyl chain, such as a linear C_10-12 alkyl chain. In some embodiments of the invention that may be mentioned herein, R may be a linear alkyl chain, e.g. R may be a linear C_6-20 alkyl chain, a linear C_8-16 alkyl chain, a linear C_10-14 alkyl chain or a linear C_10-12 alkyl chain. In other embodiments of the invention that may be mentioned herein, R may be a linear or branched C_6-20 alkenyl chain that may be mono-, di- or tri-unsaturated. In such embodiments, R may be a linear or branched C_8-16 alkenyl chain that may be mono- or di-unsaturated, for example a linear or branched C_10-14 alkenyl chain that may be mono- or di-unsaturated. In some embodiments of the invention, R may be a moiety formed by removing a hydrogen atom from an acyclic monoterpene, or R may be a moiety formed by removing a hydroxyl group from an acyclic monoterpene alcohol. In some embodiments of the invention, R may be a moiety formed by removing a hydroxyl group from an acyclic monoterpene alcohol, such as a moiety formed by removing a hydroxyl group from nerol or geraniol.

Nerol Geraniol In some embodiments of the invention, R may be a branched alkyl chain that corresponds to a hydrogenated version of the alkenyl groups mentioned above. For example, in some embodiments of the invention R may be a chain formed by the hydrogenation of an acyclic monoterpene, for example a 3,7-dimeythyloctyl group formed by hydrogenating the carbon chain of nerol or geraniol. X¹ and X² each represent H or –CH₂-Y, provided that for each triazole moiety, one of X¹ and X² is H and the other is -CH₂-Y. For the avoidance of doubt, said “triazole moiety” refers to the two moieties having the formula:

within each of formulae (I) and (II). In some embodiments of the invention, each X¹ may be the same, and each X² may be the same. When compounds of formula (I) and (II) are prepared according to the methods disclosed herein, each X¹ will generally be the same, and each X² will generally be the same. This is the case because the reaction to form the triazole ring is, depending on the catalyst used, generally selective for either a 1,4-triazole or a 1,5-triazole. In other words, the formation of the triazole rings in the compounds of formula (I) and (II) will usually result in predominantly the 1,4-triazole or predominantly the 1,5-triazole. Thus, if the compounds of formula (I) or (II) are prepared from a single Azide-alkyne Huisgen cycloaddition, the product will typically have each X¹ being the same, and each X² being the same. Without being bound by theory, it is believed that the use of a Cu(I) or Ag(I) catalyst will provide predominantly the 1,4-triazole (i.e. where each X¹ is -CH₂-Y and each X² is H), while the use of a Ru(II) catalyst will provide predominantly the 1,5-triazole (i.e. where each X¹ is H and each X² is -CH₂-Y). Thus, in some embodiments of the invention, each X¹ may be -CH₂-Y and each X² may be H. In other embodiments of the invention, each X¹ may be H and each X² may be -CH₂-Y. Within X¹ and X², each Y may be independently selected from the group consisting of a hexose sugar, a pentose sugar, a hexuronic acid, a 2-amino hexose sugar, a disaccharide and an oligosaccharide, where each Y may be bonded to the rest of the molecule (i.e. the -CH₂- moiety within X¹ and X²) via an O-glycosidic bond. Examples of hexose sugars that may be mentioned herein include glucose, mannose, and galactose. An example of a pentose sugar that may be mentioned herein is xylose. Examples of hexuronic acids that may be mentioned herein include glucuronic acid, mannuronic acid and galacturonic acid. Examples of 2-amino hexose sugars that may be mentioned herein include 2-amino glucose, 2-amino mannose, and 2-amino galactose. Examples of oligosaccharides that may be mentioned herein include isomalto-oligomers and isomers based on mannose or galactose. In some embodiments of the invention that may be mentioned herein, each Y may be independently selected from the group consisting of a hexose sugar and a pentose sugar, optionally wherein each Y may be a hexose sugar. In other embodiments, each Y may be independently selected from the group consisting of glucose, mannose, galactose, and xylose, optionally wherein each Y may be independently selected from the group consisting of glucose, mannose, and galactose. In some embodiments of the invention that may be mentioned herein, each Y may be the same. For example, in some embodiments of the invention each Y represents glucose. The compound of formula (I) or (II) may be a compound of formula (I). The compound of formula (I) or (II) may be a compound of formula (II). Specific compounds according to the invention include compounds of formula (Ia), (Ib), (IIa) and (IIb) below.

(IIa)

(IIb) References to compounds of formula (I) and/or (II) herein include, where permitted by context, references to compounds of formula (Ia), (Ib), (IIa) and (IIb). The invention provides a surfactant composition comprising a compound of formula (I) and/or a compound of formula (II), as described herein. The compounds of formula (I) and/or (II) disclosed herein, and compositions comprising them, may be used as surfactants. As such, the invention also provides the use of a compound of formula (I) and/or (II) disclosed herein, or the use of compositions comprising a compound of formula (I) and/or (II) disclosed herein, as a surfactant. The invention provides a method of stabilising an oil-in-water emulsion comprising the steps: (a) providing an oil-in-water emulsion; and (b) contacting the oil-in-water emulsion with an effective amount of a compound of formula (I) and/or (II), or a composition comprising a compound of formula (I) and/or (II), so as to stabilise the emulsion. The invention also provides methods for making a compound of formula (I) and/or (II). Thus, the invention provides a method of making a compound of formula (I) or (II), comprising the steps: (i) providing a compound of formula (Ip) or (IIp)

(III) wherein in formula (III), Z represents a sugar moiety as defined for moiety Y above, or a protected version thereof (e.g. an acetylated sugar moiety), where said sugar moiety or protected version thereof is bonded to the rest of the molecule via an O-glycosidic bond; and (iii) when Z represents a protected sugar moiety, performing a deprotecting step to provide a compound of formula (I) or (II) in which Y is not a protected sugar. In some embodiments of the invention, Z represents an unprotected sugar moiety as defined for moiety Y above. As mentioned hereinabove, the metal catalyst in this reaction may be selected from the group consisting of a Cu(I) catalyst, a Ru(II) catalyst and a Ag(I) catalyst. In some embodiments of the invention, the metal catalyst may be selected from the group consisting of a Cu(I) catalyst, and a Ru(II) catalyst. In particular embodiments of the invention, the metal catalyst may be a Cu(I) catalyst. The method of making a compound of formula (I) and/or (II) may further comprise steps of making the precursor compounds. Thus, in some embodiments the method further comprises forming the compound of formula (Ip) by the steps: (a) reacting a compound of formula (IV) with NaN₃ to form a compound of formula (Ipp)

(IV) (Ipp); and (b) reacting the compound of formula (Ipp) with a with a compound of formula R-X, where X is a leaving group (such as a halide, e.g. Br), to form a compound of formula (Ip). This synthetic route to form a compound of formula (I) is shown in Fig.2. In some embodiments, the method may further comprise forming the compound of formula (IIp) by the steps: (a) reacting a compound of formula (V) with a compound of formula R-OH to form a compound of formula (VI)

(V) (VI); (b) reacting the compound of formula (VI) with Cl₂ to form a compound of formula (IIpp)

(IIpp); and (c) reacting the compound of formula (IIpp) with NaN3 to form the compound of formula (IIp). This synthetic route to form a compound of formula (II) is shown in Fig.3. Also disclosed herein are compounds of Formula (X) and (XI).

(X)

(XI) In formula (X) and (XI), X₁ and X₂ are the same as in embodiments disclosed herein, and R⁰ represents a linear or branched C5-20 alkyl chain. Compounds of formula (X) and (XI) may be made by analogous methods to compounds of formula (I) and (II), from precursors of formula (Xp) and (XIp), respectively:

(Xp) (XIp) Compounds of formula (Xp) and (XIp) may be prepared from compounds of the formula:

where X represents a leaving group, such as a halogen (e.g. chlorine). In some embodiments, the invention provides a compound of formula (X). In some embodiments, the invention provides a compound of formula (XI). In some embodiments, the invention provides a method of preparing a compound of formula (X), as disclosed above. In some embodiments, the invention provides a method of preparing a compound of formula (XI), as disclosed above. The invention is illustrated by the below Examples, which are not to be construed as limitative. EXAMPLES Example 1: Preparation of the surfactant compounds Compounds of formula (I) and (II) may be made by different synthetic routes. Formula (I)

Formula (II)

These synthetic routes involve the same general procedures for the click coupling and deprotection, which general procedures are described below. As would be understood by a person skilled in the art, the compounds of the invention may be prepared from sugar moieties that do not comprise protecting groups (i.e when R in the above schemes represents H), such as from sugar moieties prepared using the Fischer glycosidation. A skilled person would appreciate that avoiding the use of protecting groups may provide a more economical production method, since fewer steps are involved. General Procedure 1: Click Coupling A solution of the glycoside precursor (~6 mmol) and the complementary diazido – alkane (~1.2 eq.) in MeOH (30ml) was treated with Cu(OAc)₂ (~0.2 eq.) followed by the addition of sodium ascorbate (~0.5 mmol). The reaction was stirred at room temperature overnight, then filtered and the solvent was evaporated. The crude product was taken up in CH₂Cl₂ and extracted with aqueous EDTA (0.4 M) to remove the copper catalyst. The organic solvent was dried over MgSO₄, followed by solvent evaporation. The resulting crude product was purified by flash chromatography on a 15 cm high column using hexane and ethyl acetate (1:1) as eluent to remove remaining impurities to collect the practically pure surfactant precursor. General procedure 2: Surfactant Deprotection The acetylated surfactant precursor was dissolved in methanol (30 ml), treated with a catalytic amount of NaOMe and then stirred at room temperature overnight. The solution was subsequently neutralized with ion exchange resin (Amberlite IR-120). Filtration of the resin followed by evaporation of the solvent afforded the pure compound which was then dried under vacuum over P₂O₅. Preparation of the specific precursor compounds for each synthetic route is described below. Synthesis of specific precursor compounds Synthetic route for formula (I)

(2) 1,3-diazidopropan-2-ol (2). Epichlorohydrin (1.0 g, 11.0 mmol) and sodium azide (1.51 g, 23.1 mmol) was stirred in sodium p-toluene sulfonate NaPTS (10.0 mL). The reaction was stirred at room temperature (RT) overnight and then the mixture was extracted with ethyl acetate (EtOAc) and dried over MgSO₄. The solvent was evaporated in vacuum.¹H NMR (400 MHz, CDCl₃) δ 3.92 (ddd, J = 11.0, 6.1, 4.6 Hz, 2H), 3.67 (s, 1H), 3.77 – 3.51 (m, 1H), 3.40 (td, J = 6.8, 6.0, 4.2 Hz, 10H), 2.25 (d, J = 7.3 Hz, 2H).

(3) 1-((1,3-Diazidopropan-2-yl)oxy)dodecane (3). A solution of 2 (1.0 g, 7.03 mmol), NaOH (50% concentration 20 mL) and TBAB (1.13 g, 3.51 mmol) was stirred in toluene (40 mL) in an ice bath for 20 minutes. After that 1-bromododecane (1.05 g, 7.42 mmol) was stirred in RT overnight and then the reaction was washed with water. The organic layer was dried over MgSO4 and the solvent was evaporated in vacuum.¹H NMR (400 MHz, CDCl₃) δ 3.61 – 3.48 (m, 2H), 3.34 – 3.25 (m, 3H), 1.65 – 1.53 (m, 2H), 1.44 – 1.12 (m, 18H), 0.86 (td, J = 6.9, 2.3 Hz, 3H).¹³C NMR (100 MHz, CDCl₃) δ 70.86, 51.75, 34.10, 33.90, 32.93, 32.00, 30.01, 29.74, 29.71, 29.67, 29.64, 29.50, 29.43, 28.85, 28.26, 26.03, 22.76. ^symGlc₂OC₁₂ protected(4). Precursor (3) (0.5 g, 1.61 mmol) and peracetylated propargyl glucose (0.92 g, 3.22 mmol) were coupled with copper (II) salt (Cu(OAc)2) (0.04 g, 0.24 mmol) and Na- ascorbate (0.14 g, 0.72 mmol) in MeOH (50 mL) according to the general procedure I. Chromatographic purification was applied using EtOAc – Hexane mixture at a ratio of 2:3 and final product of light yellow appearance was obtained with a yield of 73.21%.¹H NMR (400 MHz, CDCl₃) δ 7.63 (d, J = 5.9 Hz, 2H), 5.14 (td, J = 9.5, 1.4 Hz, 2H), 5.03 (td, J = 9.7, 1.5 Hz, 2H), 4.98 – 4.86 (m, 4H), 4.78 (dd, J = 12.6, 2.1 Hz, 2H), 4.64 (dd, J = 8.0, 1.1 Hz, 2H), 4.42 – 4.23 (m, 4H), 4.19 (dd, J = 12.4, 4.5 Hz, 2H), 4.11 (ddd, J = 12.3, 7.0, 3.4 Hz, 3H), 3.69 (ddt, J = 9.7, 4.8, 2.5 Hz, 2H), 3.39 (tt, J = 6.7, 3.3 Hz, 2H), 2.33 – 1.76 (m, 33H), 1.27 – 1.09 (m, 17H), 0.81 (t, J = 6.8 Hz, 3H).¹³C NMR (100 MHz, CDCl₃) δ 100.09, 100.05, 72.73, 71.98, 71.21, 68.28, 20.79, 20.70, 20.60, 14.13. ^symGlc₂OC₁₂ (5). Precursor surfactant 4 (1.11 g, 1.02 mmol) was dissolved in MeOH (50 mL) and the solution was reacted according to general procedure II.¹H NMR (400 MHz, CD₃OD) δ 8.01 (d, J = 1.0 Hz, 2H), 4.97 (d, J = 2.0 Hz, 1H), 4.93 (d, J = 2.0 Hz, 1H), 4.79 (s, 1H), 4.76 (s, 1H), 4.65 (d, J = 4.1 Hz, 1H), 4.62 (d, J = 4.0 Hz, 1H), 4.47 – 4.33 (m, 4H), 4.20 (td, J = 6.8, 3.3 Hz, 1H), 3.87 (dd, J = 11.9, 1.7 Hz, 2H), 3.71 – 3.60 (m, 2H), 3.38 – 3.14 (m, 23H), 1.40 – 1.06 (m, 21H), 0.91 – 0.84 (m, 3H).¹³C NMR (100 MHz, CD₃OD) δ 102.29, 102.26, 76.74, 76.65, 73.69, 70.29, 47.57, 47.34, 13.11. Synthetic route for formula (II) 1-(allyloxy)dodecane (7). 1 dodecanol (1.0g, 5.37mmol), NaOH (50% concentration 20mL) and TBAB (0.87g, 2.69mmol) was stirred in toluene (40mL) in an ice bath for 20 minutes. After that add 3-bromoprop-1-ene (0.97g, 8.06 mmol) was stirred at room temperature (RT) overnight. After that, the reaction washed with water. The organic layer was dried over MgSO₄ and the solvent was evaporated in vacuum.¹H NMR (400 MHz, CDCl₃) δ 5.95 – 5.81 (m, 1H), 5.23 (dq, J = 17.2, 1.6 Hz, 1H), 5.13 (dt, J = 10.3, 1.5 Hz, 1H), 3.93 (dt, J = 5.6, 1.4 Hz, 2H), 3.59 (t, J = 6.6 Hz, 1H), 3.42 – 3.29 (m, 3H), 1.72 – 1.61 (m, 1H), 1.60 – 1.49 (m, 3H), 1.53 – 1.36 (m, 1H), 1.30 (d, J = 17.1 Hz, 5H), 1.23 (d, J = 7.5 Hz, 21H), 0.98 (t, J = 7.3 Hz, 1H), 0.85 (t, J = 6.8 Hz, 4H).¹³C NMR (100 MHz, CDCl₃) δ 116.72, 71.85, 70.59, 63.00, 59.14, 32.88, 31.99, 29.83, 29.74, 29.71, 29.68, 29.58, 29.53, 29.43, 26.25, 25.85, 24.27, 22.75, 19.85. 1-(2,3-dibromopropoxy) dodecane (8). Precursor 7 (1.0g, 4.4mmol) mix with DCM and add diluted Br₂ (1.06g, 6.6mmol) in DCM dropwise in an ice bath until the reaction colour maintains dark red. The reactant was stirred for 3 hours at RT. After 3 hours of stirring, TLC was tested to determine all the double have been reacted. Then reactant was washed with sodium thiosulphate before adding MgSO4 to the organic layer before the reactant was evaporated in vacuum.¹H NMR (400 MHz, CDCl₃) δ 4.25 (dq, J = 8.0, 5.0 Hz, 1H), 3.90 – 3.74 (m, 3H), 3.63 (t, J = 6.7 Hz, 1H), 3.57 – 3.44 (m, 1H), 1.58 (ddd, J = 11.3, 7.3, 5.5 Hz, 2H), 1.28 (d, J = 9.5 Hz, 18H), 0.89 (t, J = 6.7 Hz, 3H).¹³C NMR (100 MHz, CDCl₃) δ 71.5, 62.8, 49.32, 29.63, 29.54, 29.43, 29.39, 14.12, 13.70. 1-(2,3-diazidopropoxy)dodecane (9). Add precursor 8 (1.0g, 2.6mmol) and sodium azide (0.67g, 10.4mmol) in DMSO (40mL). The reaction was stirred for 3 hours at 80°C. Then the reactant was washed with water and hexane. The product was dried over MgSO₄ before evaporating the solvent under vacuum.¹H NMR (400 MHz, CDCl₃) δ 4.25 (dq, J = 8.0, 5.0 Hz, 1H), 3.88 – 3.73 (m, 3H), 3.58 – 3.43 (m, 1H), 1.58 (ddd, J = 11.3, 7.3, 5.5 Hz, 2H), 1.39 – 1.27 (m, 9H), 1.27 (s, 9H), 0.89 (t, J = 6.7 Hz, 3H).¹³C NMR (100 MHz, CDCl₃) δ 71.5, 62.8, 60.52, 51.8, 29.65, 29.62, 29.59, 29.56, 29.52, 29.50, 29.48, 14.12. Glc₂T₂OC_12protected (10) . Precursor (9) (1.0g, 3.37mmol) and peracetylated propargyl glucose (6) (2.6g, 6.75mmol) were coupled with copper (II) salt (Cu(OAc)₂) (0.09g, 0.51mmol) and Na- ascorbate (0.3g, 1.52mmol) in MeOH (50mL) according to general procedure 1. Chromatographic purification was applied using EtOAc – Hexane mixture at a ratio 1:1 and the final product of light yellow appearance was obtained.¹H NMR (400 MHz, CDCl₃) δ 7.60 (d, J = 6.8 Hz, 1H), 7.31 (s, 1H), 5.33 – 5.16 (m, 4H), 5.15 – 5.06 (m, 3H), 5.06 – 4.83 (m, 7H), 4.65 (ddd, J = 12.7, 8.0, 4.2 Hz, 2H), 4.39 (d, J = 2.4 Hz, 2H), 4.28 (ddt, J = 10.4, 9.0, 4.6 Hz, 3H), 4.17 (ddd, J = 12.2, 6.2, 2.9 Hz, 3H), 3.48 (qq, J = 9.4, 5.8, 4.5 Hz, 2H), 2.49 (t, J = 2.4 Hz, 1H), 2.17 – 1.94 (m, 35H), 1.84 – 1.70 (m, 5H), 1.66 – 1.49 (m, 3H), 1.44 – 1.10 (m, 24H), 0.89 (td, J = 6.6, 3.5 Hz, 6H).¹³C NMR (100 MHz, CDCl₃) δ 171, 170.2, 169.4, 100.12 – 99.33 (m), 98.11, 72.74 (d, J = 1.7 Hz), 71.90 (d, J = 2.5 Hz), 71.16, 70.94, 68.28, 60.78, 20.89 – 20.46 (m), 14.12. Glc₂T₂OC₁₂. Precursor surfactant (10) (1.0g, 0.92 mmol) was dissolved in MeOH (50mL) and the solution was reacted according to general procedure II.¹H NMR (400 MHz, CD₃OD) δ 8.06 – 8.00 (m, 1H), 7.78 – 7.71 (m, 1H), 5.32 (dt, J = 9.1, 4.7 Hz, 1H), 5.02 (dq, J = 5.8, 3.1 Hz, 2H), 4.87 (d, J = 1.5 Hz, 34H), 4.79 – 4.65 (m, 2H), 4.36 – 4.23 (m, 2H), 3.95 – 3.81 (m, 3H), 3.71 – 3.59 (m, 2H), 3.52 – 3.41 (m, 2H), 3.39 – 3.09 (m, 13H), 2.08 – 1.91 (m, 1H), 1.61 – 1.48 (m, 2H), 1.38 – 1.15 (m, 16H), 0.92 – 0.81 (m, 3H).¹³C NMR (100 MHz, CD₃OD) δ 102.06, 76.71, 76.59, 73.66, 70.29, 60.68, 48.30 – 47.03, 31.8, 29.44, 29.17, 25.9, 22.4, 13.03. Preparation of a technical grade surfactant GlcOC₃ (6). D-glucose (10.0 g, 55.51 mmol) was reacted with 25.0 ml of propargyl alcohol and 2.50 g of Amberlite IR 120 (H+) resin at 70^oC for 5h to obtain a clear, amber liquid. After cooling down to room temperature, the reaction mixture was filtered to remove the used resin and concentrated in vacuo to remove unreacted propargyl alcohol. The residue was co- evaporated with water to remove traces of propargyl alcohol. After that, the residue was dissolved in methanol, to which 2.0 g charcoal powder was added and placed in a sonication bath briefly to remove dark coloured impurities. The mixture was filtered and concentrated in vacuo to dryness. Drying over P2O5 in a vacuum desiccator furnished 10.16 g (46.56 mmol, 83.9%) of a clear amber gel. Glc₂T₂OC₁₂ (7).4.20g (1.0 eq, 19.25 mmol) of technical grade propargyl glycoside and 3.19g (0.53 eq, 10.28 mmol) of (CH₂N3)2OC12 was dissolved in 100 ml of MeOH.0.35g (0.10 eq, 1.93 mmol) of Cu(OAc)2 and 0.66g (0.17 eq, 3.33 mmol) of sodium ascorbate was added to the solution and stirred at room temperature overnight. The reaction mixture was evaporated to dryness in vacuo to remove MeOH. The residue was dissolved in 1-BuOH and washed with 0.4M aqueous EDTA solution (6 x 50 ml) until the bluish green aqueous layer appears colourless. The 1-BuOH layer was concentrated in vacuo to obtain a brownish yellow gel. Overnight drying over P2O5 in a vacuum dessicator furnished 5.50g (7.36 mmol, 71.6% yield) of the product.¹H NMR (400 MHz, CD₃OD): δ = 8.01 (s, 2 H, triazole), 4.95 (2 d, 2 H,O CH₂- A), 4.78 (d, 2 H, O CH₂-B), 4.64 (dd, 2 H, NCH₂-A), 4.45-4.37 (m, 2 H, NCH₂-B), 4.36(2 d, 2 H, H-1), 4.20 (mc, CH), 3.87 (dd, 2 H, H-6A), 3.65 (dd, 2 H, H-6B), 3.36-3.23 (m, 6 H,H-3, H- 4 & H-5), 3.20 (dd, H-2), 1.40-1.07 (m, 20 H, bulk- CH₂), 0.88 (t, 3 H, CH3); 3J1,2 = 8.0,3J2, 3 = 9.0, 3J5,6A = 2.0, 3J5,6B = 5.0, 2J6 = 12.0, 2JO CH₂ = 12.5, 2JN CH₂ = 14.0, 3JN CH₂A,CH = 4.0 Hz.¹³C NMR (100 MHz, CD₃OD) δ = 145.9 (triazole-C), 126.9 (triazole-CH), 103.8 (C-1), 78.2, 78.1 (C-3 & C-5), 75.2 (C-2), 72.0 (α), 71.8 (C-4), 63.1, 63.0 (C-6 & OCH2), 52.4 (CH₂N), 32.3 (ω-2), 31.1-30.8 (bulk- CH₂), 27.2 (β), 23.0 (ω-1), 14.7 (ω). HRMS (ESI) Calc. for C33H58N6O13 [M+Na+] 769.3960 (12C33, ref/100%), 770.3993 (13C12C32, 37%); Found 769.3912 (100%), 770.3955 (37%). Example 2: Comparison of surfactant properties Surfactant properties for various surfactants are shown in Table 1 below. General structures of APG and ATG are shown in Fig.4, where the circle represents a sugar moiety and pentagon represents a triazole moiety. These differ from compounds of formula (I) and (II) at least in that they comprise only a single sugar moiety. NP-9 and NP-10 are commercially available surfactant compositions based on nonylphenol ethoxylate.

It can be seen that the surfactants of the invention have an advantageously low surface tension. The molecular surface area is also advantageously low, which is believed to be advantageous for applications such as templating (e.g. cavities in porous materials or 2-phase synthesis of nanoparticles). Example 3: Stability test Oil-in-water emulsions were prepared using a 19:1 ratio of water and oil containing 0.5% (wt/vol) of a surfactant. Three types of oil were used for the emulsion stability test: ethyl laurate, methyl laurate and paraffin oil. The formulation was mixed with a homogenizer for 2 mins at room temperature at a speed of 14,450 rpm. The emulsion samples were stored at room temperature and monitored for phase separation over a few weeks. Table 2: Emulsion stability (O/W)

NA = not tested The structures of formula (Ia), and reference compounds 17, 25, 26 and 27 are provided below (in reference compounds 17 and 25, R = H).

Formula (la)

Reference compound 17:

Reference compound 25:

Reference compound 26:

Reference compound 27:

The results show the surfactant of formula (Ia) provided stable emulsions that required several days to phase separate. This emulsion stability substantially exceeded that for the single head C12-ATG surfactant (compound 27). This confirms the improved emulsion performance obtained by introducing a second sugar head group to the surfactant. In addition, the surfactants of the invention have comparable activity to reference compound 25, whilst being much cheaper and easier to synthesise.

Claims

CLAIMS 1. A compound of formula (I) or (II):

(I)

(II) wherein R is selected from the group consisting of a linear or branched C_6-20 alkyl chain, and a linear or branched C_6-20 alkenyl chain that may be mono-, di- or tri-unsaturated; X¹ represents H or –CH₂-Y; X² represents H or –CH₂-Y; provided that for each triazole moiety, one of X¹ and X² is H and the other is -CH₂-Y; each Y is independently selected from the group consisting of a hexose sugar, a pentose sugar, a hexuronic acid, a 2-amino hexose sugar, a disaccharide and an oligosaccharide, where each Y is bonded to the rest of the molecule via an O- glycosidic bond.

2. A compound according to Claim 1, wherein each Y is independently selected from the group consisting of a hexose sugar and a pentose sugar, optionally wherein each Y is a hexose sugar.

3. A compound according to Claim 1, wherein each Y is independently selected from the group consisting of glucose, mannose, galactose, and xylose, optionally wherein each Y is independently selected from the group consisting of glucose, mannose, and galactose.

4. A compound according to Claim 1, wherein each Y is the same.

5. A compound according to Claim 1, wherein each Y represents glucose.

6. A compound according to Claim 1, wherein R is selected from the group consisting of a linear or branched C_8-16 alkyl chain, and a linear or branched C_8-16 alkenyl chain that may be mono- or di-unsaturated.

7. A compound according to Claim 1, wherein R is selected from the group consisting of a linear or branched C_10-14 alkyl chain, and a linear or branched C_10-14 alkenyl chain that may be mono- or di-unsaturated, optionally wherein R represents a C_10-12 linear alkyl chain.

8 A compound according to Claim 1, wherein R represents a linear or branched alkyl chain, optionally wherein R represents a linear alkyl chain.

9. A compound according to Claim 1, wherein R represents: (a) a moiety formed by removing a hydrogen atom from an acyclic monoterpene; or (b) a moiety formed by removing a hydroxyl group from an acyclic monoterpene alcohol.

10. A compound according to Claim 1, wherein each X¹ is the same and each X² is the same.

11. A compound according to Claim 1, wherein each X¹ is -CH₂-Y and each X² is H.

12. A compound according to Claim 1, which is of formula (I).

13. A compound according to Claim 1, which is of formula (II).

14. A compound according to Claim 1, which is a compound of formula (I) having the formula (Ia) or (Ib):

(Ia),

(Ib).

15. A compound according to Claim 1, which is a compound of formula (II) having the formula (IIa) or (IIb):

(IIa),

(IIb).

16. A surfactant composition comprising: (i) a compound of formula (I); and/or (ii) a compound of formula (II), wherein the compound of formula (I) and compound of formula (II) are each as defined in Claim 1.

17. Use of a compound according to Claim 1as a surfactant.

18. A method of stabilising an oil-in-water emulsion comprising the steps: (a) providing an oil-in-water emulsion; and (b) contacting the oil-in-water emulsion with an effective amount of a compound according to Claim 1, so as to stabilise the emulsion.

19. A method of making a compound of formula (I) or (II) according to Claim 1, comprising the steps: (i) providing a compound of formula (Ip) or (IIp)

(III) wherein in formula (III), Z represents a sugar moiety as defined for moiety Y in Claim 1, or a protected version thereof (e.g. an acetylated sugar moiety), where said sugar moiety or protected version thereof is bonded to the rest of the molecule via an O-glycosidic bond; and (iii) when Z represents a protected sugar moiety, performing a deprotecting step to provide a compound of formula (I) or (II) in which Y is not a protected sugar, optionally wherein in step (ii), Z represents an unprotected sugar moiety as defined for moiety Y in Claim 1.

20. The method according to Claim 19, wherein the metal catalyst is selected from the group consisting of a Cu(I) catalyst, a Ru(II) catalyst and a Ag(I) catalyst, optionally wherein the metal catalyst is selected from the group consisting of a Cu(I) catalyst, and a Ru(II) catalyst, more optionally wherein the metal catalyst is a Cu(I) catalyst.

21. The method according to Claim 19, further comprising forming the compound of formula (Ip) by the steps: (a) reacting a compound of formula (IV) with NaN₃ to form a compound of formula (Ipp)

(IV) (Ipp); and (b) reacting the compound of formula (Ipp) with a with a compound of formula R-X, where X is a leaving group (such as a halide, e.g. Br), to form a compound of formula (Ip).

22. The method according to Claim 19, further comprising forming the compound of formula (IIp) by the steps: (a) reacting a compound of formula (V) with a compound of formula R-OH to form a compound of formula (VI)

(IIpp); and (c) reacting the compound of formula (IIpp) with NaN3 to form the compound of formula (IIp).