GB2511137A - Chelator Molecule - Google Patents

Abstract

A compound of formula (I): Preferably, the reducing sugar unit is a reducing monosaccharide such as D-glucose, D-galactose or D mannose. In another aspect, a copper complex of the chelator molecule. The chelator molecule may be prepared by reacting an optionally protected azide-functionalised reducing sugar with tripropargylamine. A source of copper (I) may also be present and/or a reducing agent such as ascorbate. The reaction preferably occurs in aqueous conditions and is preferably conducted at alkaline pH. In another aspect, a method for promoting a copper (I) catalysed azide-alkyne cycloaddition reaction (CuAAC) wherein a an azide, an alkyne and a source of copper (I) ions are contacted with the chelator molecul or copper complex thereof.

Description

CELXOR MOLECULE

FIELD OF TE INVENTION

The invention relates to riovelwatersoiuble cneacor molecuies The invention also relates to a method for producing chelator md conies and a kit for use in copper (I) -caraiysed azidealkyne click conjuqa t:Lon (C:utP.C) of bioxnoieoules comprIsing copper I ligand molecules. The invention also relates to a novel method for promoting copper: cataiysed azide alkyne cyci. caddition reactions

BACKGROUND OF TEE INVENTION

Chelators for copper 1) ions such as TETA (tris[ (l-henzyllE l,2.Altriazoi--4yl)methyl]amine) 1.5 (Figure IA) , used in copper (I) catalysed azidealkvne cycloaddition reaction (CuAAC:) also referrc-d to as click conjugation, have been described e.ginChan, T.R, et al. , 2004. Org. Lett. 6:28535. The central tris (tri.azolylmethyi) amine core structure of TETA is mainly responsible for copper (I) coordination (Rodionov, V.P., et al., 2007.J, TAm, Ohe.m. Soc. l29:i2705i2) , while the side groups modulate the soluhil.ity of the complex and the reactivity of the ion. Chelators described in prior art utilize various side groups; however, marty of them may not be optimar in terms of eg. aqueous soluhility, ability to soiu--bilize copper (II:: ions and protect them from oxidation, reacL1v1.y, reaction conditions regusren for conjuga non to h.iomoiecules and ability to protect hio molecules from copperinduced damage by actively bind ing f ee copper ic.ns in the sclutxcn S UNFfl The crielator molecule accordino to the pre sent invention is characterized by what is cresented in rj aim 1 The copper complex according to the present invention is characterized by what is presented in claim 19.

The kit according to the present invention is characterized by what is presented in claim 22.

The method for preparing the chelator mole- cule according to the present invention is character-ized by what is presented in claim 27.

The method for promoting a copper (I)- catalyzed azide-alkyne cycloaddition reaction accord-ing to the present invention is characterized by what is presented in claim 34.

The use of a chelator molecule or a copper complex according to the present invention is charac-terized by what is presented in claim Ii.

BRIEF DESCRIPTION OF Tat DRAWINGS

Figure 1 shows the structures of TBTA and TGTA (tris{ [1-(6-D-galactosyl)-1B-1,2,3-triazol-4- yllmethyl}amine). A. Structure of TETA and its pro-posed copper(I) chelating mode as described in Rodionov, V.0., et al., 2007. J. Am. Chem. Soc. 129:12705-12. L represents an external ligand coordi-nating to copper. B. Structure of TGTA. TGTA has the same tris(triazolylmethyl)amine core structure as TBTA but is water-soluble due to the intrinsic hydrophilic character of the sugar units.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a chelator molecule comprising a core structure that is capable of coordinating copper(I} and side groups comprising a reducing sugar unit.

The copperCl) coordinating core structure comprises a tris(triazolylmethyl)anzine group.

The present invention relates to a chelator molecule represented by formula I

N N h

Formula I wherein each of R1, R2 and R3 is independently selected from the group consisting of a reducing sugar unit, C1-C9 alkyl, C3-C8 carbocyclyl, aryl, Ci-Ce alkyl-aryl, C1-C, alkyl-tC3-C8 carbocyclyl), heterocyclyl, C-C8 alkyl-(C3-C heterocyclyl), and 13; with the proviso that at least one substitu-ent selected from R1, R2 and It3 is a reducing sugar unit.

In this context, the term "tris(triazolylmethyl)amine group" should be under- stood as referring to a 1-(1R-triazol-4-yl}-N,N- bis (1H-triazol-4-ylmethyi)methanamine group. Substitu-ents It1, It2 and a, are thus bonded via a bond to the tris(triazolylmethyl)amine group as shown in formula I. In this context, the term "reducing sugar unit" or "reducing sugar" should be understood as re- ferring to a simple sugar moiety or a reducing mono-saccharide or a derivative thereof, or a combination of two or more sugar moieties or monosaccharides cova- lently linked to form a disaccharide, an oligosaccha-ride, or a polysaccharide, wherein the combination comprises a reducing monosaccharide.

The term "oligosaccharide" should be under-stood as referring to a saccharide comprising 2 to S monosaccharide units.

The term "polysaccharide" should be under-S stood as referring to a saccharide comprising more than 8 monosaccharide units.

A reducing sugar unit may either comprise an aldehyde or ketone group or be capable of forming one in solution. Said aldehyde or ketone group allows the sugar to act as a reducing agent4 The term "reducing sugar unit" may, in this context, also refer to a sugar unit which may be con-sidered a relatively weak reducing agent but which still displays some reducing activity.

In one embodiment, the reducing sugar unit is a group that includes an open chain or cyclized mono-mer unit based upon an open chain form of compounds having the chemical structure H(CHOH)nC(=O}(CHOH)mH, wherein the sum of n4-m is an integer in the range of 2 to 8. Thus, a monomer unit of a reducing sugar may in- clude a triose, a tetrose, a pentose, a hexose, a hep-tose, an octose, a nonose, or any mixture thereof.

In one embodiment, a hydroxyl group in the chemical structure of the reducing sugar unit is re-placed with a group such as H, amino, amine, acylamido, acetylamido, halogen, mercapto, acyl, ace-tyl, phosphate or sulphate ester, and the like.

In one embodiment, the reducing sugar unit further comprises a functional group such as carboxyl, carbonyl, hemiacetal, acetal or thio group.

In one embodiment, a hydroxyl group or an other functional group of the reducing sugar unit is protected with a protecting group such as silyl, ben-zyl, benzoyl, or the like.

The tern "alkyl" should be understood as re-ferring to a straight or branched chain saturated or unsaturated hydrocarbon having the indicated number of carbon atoms (e.g., "C-C8 alkyl" refers to an alkyl group comprising from 1 to 8 carbon atoms). When the number of carbon atoms is not indicated, the alkyl group comprises from 1 to 8 carbon atoms. Representa-tive "C1-C3 alkyl" groups include (but are not limited to) methyl (Me, CR3), ethyl (Ct, CM2CR,), 1-propyl (n-Pr, n-pzopyl, CH2CR2CH3), 2-propyl (i-Pr, isopropyl, CH(CR3)2), 1-butyl (n-Eu, n-butyl, CR2CR2CR,CR3), 2-methyl-1-propy]. (i-Eu, isobutyl, CH2CH(C113}2), 2-buty].

(s-Eu, s-butyl, CR(CM,)CR2CH,), 2-methyl-2-propyl Ct-Eu, tert-butyl, C(CH,),), 1-pentyl (n-pentyl, CM2CR2CH2CR2CH,), 2 -pentyl (CR (UI3) CH2CH2CH9), 3-pentyl (CH(CH2CH3)2), 2-methyl-2-butyl (C(CR,)2CM2CR3), 3-methyl'-2-butyl (CR (CR,) CR (CR,)2), 3-methyl-1-butyl (CR2CR2CR(CH,)2), 2-methyl-1-butyl (CH2CH(CM,)CH2CR,), 1-hexyl (CR2CH2CR2CH2CM2CH3), 2-hexyl (CH (CM,) CH2CH2CH2CH,), 3-hexyl (CH(CR2C113) (CR2CH2CR,)), 2-methyl-2-pentyl (C(CH,)2CR2CH2C11,), 3-methyl-2--pentyl (CH(CH,)CH(CR,)C}i2CR,), 4-methyl-2-pentyl (CM(CR,)CR2CM(CR,)2), 3-methyl-3-penty].

(C (CM,) (CR2C}{,) 2), 2-methyl-3-pentyl (CH(CR2CH,) CR (CR,)2), 2, 3-dimethyl-2-butyl (C(CR,)2CR(CR,)2), and 3,3-dintethyl-2-butyl (CH(CH,)C(CE3)3). An alkyl group may be unsubstituted or substituted with one or more groups including, but not limited to, OR, O(C1-C8 alkyl), aryl, COR', OCOR', CONR2, CONRR', CONR'2, NHCOR', Ski, SO2R', SOR', OSO2OH, OPO(OM)2, halogen, N,, NH2, NRR', NR'2, NHCO(C1-C8 al-kyl) or CM, wherein each TV is independently either H, C1-C0 alkyl or aryl. The term "alkyl" should also be understood as referring to an alkylene, a saturated, branched or straight chain or cyclic hydrocarbon radi-cal of 1 to 18 carbon atoms, and having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkane. Typical such alkylenes include (but are not limited to) methylene (CR2) 1,2-ethyl (CR2CH2), 1, 3-propyl (CH2CH2CH2), 1,4-butyl (CH2CR2CH2CH2), and the like. The term "alkyl" should also be understood as referring to arylalkyl and heteroarylalkyl radicals as described below.

The term "alkenyl" should be understood as referring to a C2-C hydrocarbon containing normal, secondary, tertiary or cyclic carbon atoms with at least one site of unsaturation, i.e., a carbon-carbon, sp2 double bond. Examples include, but are not limited to ethylene or vinyl (CR-CR2), allyl (C112CH-CH2), cyclopentenyl (C5H,), and 5-hexenyl (CH2CB2CR2CH2CHCH2).

The term "alkenyl" should also be understood as refer-ring to an alkenylene, an unsaturated, branched or straight chain or cyclic hydrocarbon radical of 2-18 carbon atoms, and having two monovalent radical cen-ters derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent al-kene. Typical alkenylene radicals include, but are not limited to, 1,2-ethylene (CH=CH).

The term "alkynyl" should be understood as referring to a C2-C hydrocarbon containing normal, secondary, tertiary or cyclic carbon atoms with at least one site of unsaturation, i.e., a carbon-carbon, sp triple bond. Examples include, but are not limited to acetylenic (CCH) and propargyl (CH2CCR). The term "alkynyl" should also be understood as referring to an alkynylene, an unsaturated, branched or straight chain or cyclic hydrocarbon radical of 2-18 carbon atoms, and having two monovalent radical centers derived by the removal of two hydrogen atoms from carbon atoms of a parent alkyne. Typical alkynylene radicals include (but are not limited to) acetylene (n:.C), propargyl (CH2CaC), and 4-pentynyl (CH2CH2CH2CEC).

The term "aryl" should be understood as re-ferring to a monovalent aromatic hydrocarbon radical of 6-20 carbon atoms derived by the removal of one hy- drogen atom from a single carbon atom of a parent aro--matic ring system. An aryl group may be unsubstituted or substituted. Typical ary.L groups include (but are not]. imited to) radicals derived trout benrene, suhsti tuted bensene, pnenyl, napht.hale:ne anthracer-e phenyl, and the like. Anaryl nay he substituted with one or more groups including, but not limited to, OH, o (CC aikyl) aryl, COP: * COOP. , CCNH, , CONHR COUP.'2, NhCOR', PH, sC:2, SOP.', OSO,OH, CPU (OH) 2' halo-gen, N, NH7, NHR' , NP.', NHCO (OrCa aikyl) or ON, SO WktQteifl each P.' is independently either H, c:1o alkyl or aryl. The term "aryl" should also be u.nde.rsroou as referi..ing to an arylene group which is an aryl group having two covalent bonds and can he in the pare, me ta or ortho configurations, in which the phenyl group can be unsubstituted. or substituted with up to four grouns anciuding hut riot. limited to OH 0 (OC alky]. ) ary]. , COP. * DOOR, COUP.2 CONHR COUP. 2 NECOR, PH, SO,R 3CR, 05020H, CPU (OH) 2' halogen, N, NH,, NHR' Na,, NHCO(C.,CR alkyl) or ON, wherein each R isinde--pendent.ly either Ii, G1C ai.kyl or sty].

The term hi.rylaikyl" should he unders tood. as referring to an acyclic a.lkyl radical in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp' carbon atom, is replaced with an ar 2.5 yl radical. Typical arylal.kyl groups include (hut are not limited to) henzyl, 2-henylethan].yl, 2 pneny1etrten1-yi, napnrr1vlmethyt, 2-naphthytethan-l yl, 2-naphthylethenl-yl, naphthobenzyi, naphthophenylethan-i--yl, and the like. The a.rylal.ky.l group may comprise 6 to 20 carbon atoms, e.g., the al-kyl moiety, includinq alkanyl, aikenyi or aikynyl groups, of the arylalkyl group:s 1 to 6 carbon atoms and the aryl moiety is 5 to 14 carbon atoms Tite term "heteroarylalkyl" should be under--stood as referring to anacyclicalky].radic in which one of the hydrocen atoms bonded to a carbon at- om, typical 117 a terminal or sp carbon atom, is re-placed with a heteroaryl radical. Typical heteroarylalky]. groups include (but are not limited to) 2-benzimidazolylmethyl, 2-furylethyl, and the like. The heteroarylalkyl group comprises 6 to 20 car-bon atoms, e.g., the alkyl moiety, including alkanyl, alkenyl or alkynyl groups, of the heteroarylalkyl group is 1 to 6 carbon atoms and the heteroaryl moiety is 5 to 14 ring atoms, typically 1 to 3 heteroatoms selected from N, 0, P, and 5, with the remainder being carbon atoms4 The heteroary]. moiety of the heteroarylalkyl group may be a monocyclyl having 3 to 7 ring members t2 to 6 carbon atoms) or a bicyclyl having 7 to 10 ring members (4 to 9 carbon atoms) and 1 to 3 heteroatoms selected from N, 0, B, and 8, for example a bicyclo [4,5], (5,5], (5,6], or (6,6] sys-tem.

The terms "substituted alkyl", "substituted aryl" and "substituted arylalkyl" should be understood as referring to alkyl, aryl, and arylalkyl, respec-tively, in which one or more hydrogen atoms are each independently replaced with a substituent. Typical substituents include but are not limited to X, K, -0-, OR, SR, 2, NR2, N1, NR, CX1, CN, OCN, SCN, N.C0, NCS, NO, NO2, =1429 143, NRCOR, COlt, CONK2, SO3, SO3H, 502R, OSO2OR, 30214R, 50K, OPO(OR)2, P0(0K)2, -P03-, P03H2, COlt, COX, C(=S)R, CO2R, -C02-, C(=S)0R, COSK, C(S)5R, CONK2, C(-S)NR2, and C(=NR)NR2, where each X is independently a halogen: F, Cl, Br, or I; and each P is independently H, C2-C13 alkyl, C6-C20 aryl, C3-C4 heterocyclyl or protecting group. Alkylene, alkenylene, and alkynylene groups as described above The terms "heteroaryl" and "heterocyclyl" should be understood as referring to a ring system in which one or more ring atoms is a heteroatom, e.g., nitrogen, oxygen, phosphate and sulfur. The heterocyclyl radical comprises 1 to 20 carbon atoms and 1 to 3 heteroatoms selected from N, 0, Pt and S. A heterocyclyl may be a monocyclyl having 3 to 7 ring members (2 to 6 carbon atoms and 1 to 3 heteroatom.s selected from N, 0, 2, and S} or a bicyclyl having 7 to 10 ring members (4 to 9 carbon atoms and 1 to 3 heteroatoms selected from N, 0, 2, and 5), fox exam-ple: a bicyclo (4,5), (5,5], (5,6], or (6,61 system.

Reterocycles are described in Paquette, "Principles of Modern Heterocyclic Chemistry" (il. A. Benjamin, New York, 1968), particularly Chapters 1, 3, 4, 6, 7, and 9; "The Chemistry of Heterocyclic Compounds, A series of Monographs" (John Wiley & Sons, New York, 1950 to present), in particular Volumes 13, 14, 16, 19, and 28; and J. Am. Chem. Soc. 82:5566 (1960).

Examples of heterocyclyls include, by way of example and not limitation, pyridyl, clihydroypyridyl, tetrahydropyridyl (piperidyl), thiazolyl, tetrahydrothiophenyl, sulfur oxidized tetrahydrothiophenyl, pyrimidinyl, furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, tetrazolyl, benzofuranyl, thianaphthalenyl, indolyl, indolenyl, quinolinyl, isoqui.nolinyl, benaimidazolyl, piperidinyl, 4-piperidonyl, pyrrolidinyl, 2- pyrrolidonyl, pyrrolinyl, tetrahydrofuranyl, bis- tetrahydrofuranyl, tetrahydropyranyl, bis-tetrahydropyranyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl, octahydroisoquinolinyl, azocinyl, triazinyl, 611-i, 2,5--thiadiazinyl, 2ff, 6H-1,5,2-dithiazinyl, thienyl, thianthrenyl, pyranyl, isobenzofuranyl, chromenyl, xanthenyl, phenoxathinyl, 2H-pyrrolyl, isothiazolyl, isoxazolyl, pyrazinyl, pyridazinyl, indolizinyl, isoindolyl, 311-indolyl, 1H-indazolyl, purinyl, 4H-quinolizinyl, plithalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, 4a11-carbazolyl, carbazolyl, f3-carbolinyl, phenanthridinyl, acridinyl, pyrimidinyl, phenanthrolinyl, phenazinyl, phenothiazinyl, furazanyl, phenoxazinyl, isothromanyl, chromanyl, imidazolidinyl, imidazolinyl, pyrazolidthyl, pyrazolinyl, piperazinyl, indolinyl, isoindolinyl, quinuclidinyl, morpholinyl, oxazolidinyl, benzotriazolyl, benz isoxazolyl, oxindolyl, benzoxazolinyl, and isatinoyl.

By way of example and not limitation, carbon- bonded heterocycles may be bonded at the following po- lo sitions: position 2, 3, 4, 5, or 6 of a pyridine; po-sition 3, 4, 5, or 6 of a pyridazine; position 2, 4, 5, or 6 of a pyrimidine; position 2, 3, 5, or 6 of a pyrazine; position 2, 3, 4, or 5 of a furan, tetrahydrofuran, thiofuran, thiophene, pyrrole or tetrahydropyrrole; position 2, 4, or 5 of an oxazole, imidazole or thiazole; position 3, 4, or 5 of an isoxazole, pyrazole, or isothiazole; position 2 or 3 of an aziridiie; position 2, 3, or 4 of an azetidine; position 2, 3, 4, 5, 6, 7, or 8 of a quinoline; or po- sition 1, 3, 4, 5, 6, 7, or 8 of an isoquinoline. Car- bon bonded heterocyclyls may include 2-pyridyl, 3- pyridyl, 4-pyridyl, 5-pyridyl, 6-pyridyl, 3- pyridazinyl, 4-pyridazinyl, 5-pyridazinyl, 6-- pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 6-pyrimidinyl, 2-pyrazinyl, 3-pyrazinyl, 5-pyrazinyl, 6-pyrazinyl, 2-thiazolyl, 4-thiazolyl and 5-thiazolyl.

By way of example and not limitation, nitro-gen bonded heterocyclyls may be bonded at position 1.

of an aziridine, azetidine, pyrrole, pyrrolidine, 2- pyrroline, 3-pyrroline, imidazole, imidazolidine, 2- imidazoline, 3-imidazoline, pyrazole, pyrazoline, 2-pyrazoline, 3--pyrazoline, piperidine, piperazine, indole, indoline, or la-indazole; position 2 of a isoindole or isoindoline; position 4 of a morpholine; and position 9 of a carbazole or 3-carboline. Still more typically, nitrogen bonded heterocyclyls include 1-aziridyl, 1-azetedyl, 1-pyrrolyl, 1-imidazolyl, 1-pyrazolyl and 1-piperidinyl.

The term "carbocyclyl" should be understood as referring to a saturated or unsaturated ring having 3 to 7 carbon atoms as a monocycle or 7 to 12 carbon atoms as a bicycle. Monocyclic carbocyclyls have 3 to 6 ring atoms, still more typically 5 or 6 ring atoms.

Sicyclic carbocyclyls have 7 to 12 ring atoms, e.g., arranged as a bicyclo [4,5], (5,5], [5,6] or [6,6) system, or 9 or 10 ring atoms arranged as a bicyclo 5,6) or [6,6] system. Examples of monocyclic carbocyclyls include cyclopropyl, cyclobutyl, cyclopentyl, 1-cyclopent-1-enyl, 1-cyclopent-2-enyl, 1-cyclopent-3-enyl, cyclohexyl, 1-cyclohex-1-enyl, 1-cyclohex-2-enyl, 1-cyclohex-3-enyl, cycloheptyl and cyclooctyl.

In one embodiment, at least two substituents selected from R1, R2 and R3 are reducing sugar units.

In one embodiment, each substituent selected from R, R2 and a3 is a reducing sugar unit.

In one embodiment, the reducing sugar unit comprises a reducing monosaccharide, a reducing disac-charide, a reducing oligosaccharide, or a reducing polysaccharide.

In one embodiment, the reducing sugar unit is a reducing monosaccharide, a reducing disaccharide, a reducing oI.igosaccharide, or a reducing polysaccha-ride.

In one embodiment, the reducing oligosaccha-ride comprises 2, 3, 4, 5, 6, 7 or B monosaccharides.

In one embodiment, the reducing sugar unit comprises a reducing monosaccharide.

In one embodiment, the reducing sugar unit is a reducing monosaccharide.

In one embodiment, the reducing monosaccha-ride comprises, but is not limited to, a simple aldose such as glyceraldehyde, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, galactose, talose or mannoheptulose; a simple ketose such as dihydroxyacetone, erythrulose, ribulose, xylulose, psicose, fructose, sorbose, tagatose or sedoheptulose; a deoxysugar such as fucose, 2-deoxyglucose, 2-deoxyribose or rhamnose; a sialic acid such as ketodeoxynonulosonic acid, N-acetylneuraminic acid or 9-O-acetyl-N--acetylneuraminic acid; a uronic acid such as glucuronic acid, galacturonic acid or iduronic ac-id; an amino sugar such as 2-amino-2-deoxygalactose or 2-arrtino-2-deoxyglucose; an acylamido sugar such as 2-acetamido-2-deoxygalactose, 2-acetamido-2-deoxyglucose or N-glycolylneuraminic acid; a phosphorylated sugar such as 6-phosphomannose; a sulphated sugar such as 6-sulpho-N-acetylglucosamine or 3-suiphogalactose; or any derivative or modification thereof.

The reducing monosaccharide may be a reducing monosaccharide in open-chain, pyranose or furanose form, or as the a-or -anoxner; or in any combination thereof.

Carbohydrate nomenclature in this context is essentially according to recommendations by the IUPAC- tUB Commission on Biochemical Nomenclature (e.g. Car-bohydrate Res. 1998, 312, 167; Carbohydrate Res. 1997, 297, 1; Eur. J. Biochem. 1998, 257, 293) In one embodiment, at least one substituent selected from R1, H2 and R3 comprises a reducing mono-saccharide.

In one embodiment, at least one substituent selected from R, H2 and H3 is a reducing monosaccha--ride.

In one embodiment, at least two substituents selected from K1, K2 and R3 comprise a reducing mono-saccharide.

In one embodiment, at least two substituents selected from R1, R2 and R3 are reducing monosaccha-rides.

In one embodiment, each substituent selected from R, R2 and It3 comprises a reducing monosaccharide.

In one embodiment, each substituent selected from R1, R3 and Ra is a reducing monosaccharide.

In one embodiment, the reducing monosaccha-ride is in the D-or L-configuration.

In one embodiment, the reducing monosaccha-ride is represented by formula II x5 1 >X Formula II wherein X' is either OH, H, hydroxymethyl, methyl, carboxyl, substituted carboxyl, C1-C6 alkyl or ? is either absent or CH(X4); X2, X, X4 and X5 are each independently either OH, H, amino, C1-C6 alkylamine, C1-C6 alkylether, C1-C6 alkylester, halogen, mercapto, C2-C5 acylamide, carbox-yl, substituted carboxyl, C-C6 alkyl, substituted C1-C6 alkyl, phosphate ester, sulphate ester, or a bond to the tris(triazolylrnethyl)amine group; with the proviso that one substituent se'-lected from X2, X3, X4 and X5 is a bond to the tris(triazolylmethyl)amine group, or x2, x3, x4 or x5 is bonded via a bond to the tris(triazolylmethyl)amine group.

In one embodiment, one substituent selected from X2, X3, X4 and X5 is a bond to the tris(triazolylmethyl)amine group.

in one embod.imertt X1, X, X or X is OH;, H, amino, C[CE alkvlamine C-O-. alkylether, C1C alkylester, halogen, mercapto, C2C5 acylamide, carbox yl, suhsrtuted carboxyl, OrC alk.yl, substituted CC S a.ikyl, phosphate ester, or sulphate ester; and is bonded via a bond to i.-.he tras ( tria.zolylmetnyi. ) amine group in one embodiment, Y is 011(X4) ; and X2, X and K' are each independently either OH or H, in one embodiment, Yls absent; and x2 and X3 are each independently either OH or H, in one embodi:menc., X2, H3 and K' are each:Ln.' deoendent.1. y either OH or H in one embodiment, XL, X and r are each in dependently either OH or H; X isa 01C alkyl; and X is bonded via a bond to the tris (triazolyimethyl) amine group.

in one embodiment, X is the bond to the tris (triazoly.imethvl)axrine group.

in one embodiment, the reducing monosaccha ride is an aldobexose represented. by formula Iii OH2

-OH HO)H

Eorniula 11.1 wherein OH, a bonded via a bond to the trrs (triazolyimethyl) amine group.

The wavy single bond at X' of formula II or at the OH orcup in forriul a 1i1 tndi cafes unsoecired stereochemistry of the bond due to the tact that the structure mai be an c' anomer, a 3"anomer,anopen---chain form, a pyranose or a furanose or a mixture thereof due to niutarotation. However, other carbons in formulas II and III may also be chiral and have dif-ferent relative configurations.

In one embodiment, the aldohexose is selected from the group consisting of 0-and fr-forms of allose, altrose, glucose, mannose, gulose, ictose, galactose and talose.

In one embodiment, the aldohexose is selected from the group consisting of D-glucose, D-galactose and D-mannose.

In one embodiment, the reducing monosaccha-ride is sialic acid.

In one embodiment, the sialic acid is select-ed from the group consisting of ketodeoxynonulosonic acid, N-acetylneuraminic acid and 9-O-acetyl-N-acetylneuraminic acid.

In one embodiment, the sialic acid is N-acetylneuraminic acid.

In one embodiment, K1 K2 a K3 In one embodiment, the chelator molecule is selected from the group consisting of tris(fl-(6-D-galactosyl) -lB-i, 2, 3-triazol--4-yl]methyl} amine, tris{(1-(6-D-glucosyl)-1H-1,2,3-triazol--4- yl]methyljamine and trisi [1-(6-D-mannosyl)-1H-1,2,3-triazol-4-yl]methyl) amine.

In one embodiment, the chelator molecule is selected from the group consisting of tris{(l-(6-L-galactosyl) -lB-i, 2, 3-triazol-4-yl I methyl} amine, trisj (1-(6-L-glucosyl)-1H-1,2, 3-triazol-4- yl]methyl}amine and tris{(1-(6-L-mannosyl)-tH-1,2,3-triazol-4-yljmethyl}amine.

The chelator molecule according to the inven-tion is useful as a chelating or a complexing agent for a variety of metal ions, including but not limited to copper, regardless of their efficacy for promoting a CuAAC reaction.

Copper(I} is required in a catalytic amount to catalyse a CuAAC reaction.

The present invention also relates to a cop-per complex comprising a chelator molecule according to the invention complexed with a copper ion.

In one embodiment, the copper ion is a cop-perU) ion.

In one embodiment, the copper ion is a cop-perCh) ion.

The present invention also relates to a kit comprising a chelabor molecule according to the invert-tion or a copper complex according to the invention.

In one embodiment, the kit is suitable for promoting a copper (1)-catalysed azide-alkyne cycloaddition reaction.

In one embodiment, the kit further comprises a source of copper(I). The source of copper(I) may be provided in the form of a copper (I) salt such as for example Cul, CuBr, CuOTf*C6H6 or [Cu(NCCH3)4J. The source of copper (I) may also be provided together with a co-solvent or the kit may further comprise a cc-solvent such as acetonitrile, or further agents such as a nitrogen base or amine, e.g. 2,6-lutidirie, tn-ethylamine, N, N, N-trimethylethylenediamine, diisopropylethylazuine, pyridine, proline or other au-phatic amine. Such co-solvents or further agents may assist in making the copper(I) salt soluble or prevent oxidation of copper (I) to copper (Ii). This embodiment has the added utility that copper is provided directly in the active form that is capable of catalysing a CuAAC reaction. Further reducing or oxidising agents or steps for preparing copper(I} may not be necessary.

A source of copper(I) may also comprise means for providing copperCl). Such means may comprise e.g. a source of copper(II) and a reducing agent capable of reducing copper(II) to copper(I); or copper(0) metal and an agent capable of oxidising copper (0) metal to copper(I). Such means may allow the preparation of copper(I) prior to adding the copper CI) to the chelator molecule according to the invention or to a CuAAC reaction.

In one embodiment, the kit further comprises a source of copperClt). The source of copperCil) may be e.g. a salt such as the readily available sulphate salt such as CuSO45H2O. This embodiment has the added utility that copper(II) salts may be more readily sol-uble, less costly or often purer than copper(I) salts.

The source of copper (II) may also be consid-ered to comprise means for providing copper(II).

In one embodiment, the kit comprises a source of copper(1) and a source of copper(II).

In one embodiment, the kit further comprises means for providing copper (I) and means for providing copper(II).

In one embodiment, the kit further comprises a reducing agent capable of reducing copper(II) to copper(I). A reducing agent capable of reducing cop-per(I1) to copperCl) may be e.g. ascorbate, quinone, hydroquinone, vitamin Ki, glutathione, cysteine, Fe2, or an applied electric potential. Said reducing agent may also be a metal selected from the group con-sisting of Cu, Al, Be, Co, Cr, Fe, Mg, Mn, Ni, and Zn.

The kit may optionally comprise a further component, such as a buffer, a solvent, instructions for using the kit or an agent suitable for sequester-ing or chelating copper ions to quench the reaction.

In one embodiment, the kit further comprises means for conducting the reaction in alkaline pH.

In one embodiment, the kit further comprises a buffer with alkaline pH.

The invention further relates to a method for preparing the chelator molecule according to the in-vention, which method comprises the step of reacting an azide-functionalised reducing sugar unit with tripropargylamine (N,N-di(2-propyn-1-yl)-2-propyn-1-amine).

In one embodiment, an azide-functionalised reducing sugar unit is reacted with tripropargylamine (N,N-di (2-propyn-1-yli -2-propyn-1-anine) in the pres-ence of a source of copper (I).

S The term "azide-functionalised reducing sugar unit" should be understood as referring to a reducing sugar unit which comprises an azide group.

In one embodiment, the azide-functionalised reducing sugar unit is protected by a protecting group. One or more groups in the azide-functionalised reducing sugar may be protected. Said groups may be the same or different. For instance, hydroxyl groups of a reducing sugar unit such as an aldohexose may be protected. The protecting group may be, but is not limited to, e.g. any suitable hydroxyl or diol pro-tecting group such as isopropylidene acetal, ethylidene acetal, cyclopentylidene ketal, cyclohexylidene ketal, benzylidene acetal, substituted benzylidene acetal, cyclic carbonate, an ester, ether or the like. Various protecting groups and steps of deprotecting are known in the art.

In one embodiment, the method further com- prises the step of deprotecting the azide-functionalised reducing sugar unit. The step of deprotecting the azide-functionalised reducing sugar unit may be carried out depending on the protecting group and other features of the system and may com-prise e.g. cleavage in the presence of acid.

In one embodiment, the azide-functionalised reducing sugar unit is an azide-functionalised reduc-ing monosaccharide.

In one embodiment, an azide-functionalised reducing sugar unit is reacted with tripropargylamine (N,N-di (2-propyn-1-yl) -2-propyn-1-amine) in the pres-ence of a catalytic amount of copperCl) ions.

In one embodiment, art azide-functionalised reducing sugar unit is reacted with tripropargylamine J_ 9 (N,N-di (2-propyn-l--yl)-2--prc:-pyn---l ---amine) in the pres---ence of a source of copper(1I) In one embodiment., an azide-functionaliseci reducing sugar unit: is reacted with traproparqyamne S in the presence of a source of copper (II) ions and a reducing agent capable of reducing copper (II) to cop--per(I) ]:n one emhodiment an azide-functionalised reducing sugar unit is reacted with tr ipropargylarnine (N, N-di (2-nr opyn-1 --yl --2-propyn-1-amine) in the pres--- ence of a reduc:nu agent canable of-reducing cop-per(T.l) to copner(I) In one embodiment, the reducing agent capable of reducing cop-per (II) to copper (I) is selected from the grout) cons isting of ascorbate, quinone, hydroqu i-none, vitamin Ki * glutai:hione, cyst:eine, Fe, co:*, and an applied electric potential; or is a metal selected from the group consisting of Cu, 1\l, Be, Co, Cr, Fe, Mg, Mn, Ni, and Zn The reducing agent capable of reducing cop-per ( :[I) to copper I) may ne present in order to reduce copper (11) to copper (.1) , regardless of whether a source c-f cc-poe.r (I) or a source ci: copper (II) is pre-sent. The presence of a reducing agent has the added utility that it reduces the oxidising effect of any oxygen present in the reaction system, which may cth---erwise oxidise copper 1) to copper (I I The nresent invention also relates to a math--od for promoting a copper (Ti -cata:tysed a.zide-alkyne cycloaddition reaction, wherein the methd camprises contactinc-a a aside and an alkyne with a source of copper ions in the presence of a chelatcr moiecule ac-cording to the invention or with a copper complex ac cording to the invent ion -The method shoulo'he understood as-a general method for prc-moting any copper' I) --catalysed aide-alkyne cycloaddition reaction and is therefore not limited to any particular organic azide or alkyne.

In one embodiment, the alkyne is a terminal alkyne.

The method is useful, for example, for bio-conjugation reaction conditions that may be used for preparing e.g. antibody-drug conjugates.

In one embodiment, the azide or the alkyne comprises a biomolecule.

In one embodiment, the biomolecule comprises a protein.

In one embodiment, the protein comprises an antibody.

In one embodiment, the antibody is a recombi-nant antibody.

In one embodiment, the antibody is a mono-clonal antibody4 In one embodiment, the azide or the alkyne comprises a payload molecule.

Tn this context, the term "payload molecule" should be understood as referring to any moiety that may be modified to comprise an azide or alkyne moiety.

In one embodiment of the present invention, the payload molecule is selected from the group con-sisting of a cytotoxic agent and a labelling molecule, such as a fluorescent label or a radioactive label.

In one embodiment of the present invention, the payload molecule is a cytotoxic agent.

In this context, the term "cytotoxic agent" should be understood as referring to a molecule that has the capability to affect the function or viability of a cell. The cytotoxic agent may be any compound that results in the death of a cell, or induces cell death, or in some manner decteases cell viability.

In one embodiment, an azide and an alkyne are contacted with a source of copper ions in the presence of a chelator molecule according to the invention or with a copper complex according to the invention in aqueous solution.

In this context, the term "aqueous solution" should be understood as a solution in which water is S the primary solvent. An aqueous solution may further comprise a secondary solvent.

In this context, the term "a source of copper ions" should be understood as referring to a source of copper(I) and/or a source of copper(Ir).

In one embodiment, copper(I) ions are present in a catalytic amount.

In one embodiment, an azide and an alkyne are contacted with a source of copper ions in the presence of a chelator molecule according to the invention or with a copper complex according to the invention and in the presence of a reducing agent capable of reduc-ing copper(II) to copper(I}.

The reducing agent capable of reducing cop-per (II) to copper(I) may be present in order to reduce copper(II) to copper (I), regardless of whether a source of copperCi) or a source of copper(II) is pre-sent. The presence of a reducing agent has the added utility that it reduces the oxidising effect of any oxygen present in the reaction system, which may 0th-erwise oxidise copper(t) to copperCil).

In one embodiment, an azide and an alkyne are contacted with a source of copperCil) ions in the presence of a chelator molecule according to the in- vention or with a copper complex according to the in- vention and in the presence of a reducing agent capa-ble of reducing copper(I1) to copper(I).

In one embodiment, the reducing agent capable of reducing copperClt) to copper(I) is selected from the group consisting of ascorbate, quinone, hydroqui-none, vitamin Ki, glut.athione, cysteine, Fe2, Ca24, and an applied electric potential; or is a metal selected from the group consisting of Cu, Al, Be, Co, Cr, Fe, Mg, Mn, Ni, and Zn.

However, in some embodiments of the tnven---tion, a reducing agent (other than the chelator mole cole according to the invention or the copper complex according to the invention) may not he necessary. The reducing sugar unit present in the chelator molecule or the copper complex according to the invention may function as a reducing agent. apable of reducing cop-per (II) to conper (I) or prevent oxidation of copper(I) to copper (Jfl In one embodiment the reducing sugar unit.

functions as a reducing agent in alkaline ph In one embodiment, an az:Lcie and an alkyne aie contacted with a source of coppei. ions in the presence of a chelator molecule according to the invention or with a copoer complex accordnc to the invention In alkaline p This embodiment has the added utility that reducing suqar unir..s are most effective in reducing copper in alkaline ph.

In one embodiment, the alkaline p1-i is at least 7, ox at.. least 8, or at. least 9, or a.t least 1.0, or at least 11, In one embodiment, the alkaline pH is 7 1 1, 7--lU. 7-9, 7--B, 8--il, 8'l0, 8-9, 9-ll, 9-l.0, or about 8, about 8 5, about 9, or about 95 In ccc cmbc:diment, sucn alkaline ph is se-- lec,ted that. it does not promote damage to the the as---ide and the a kyne during their contacting with a source of copper I I ions.

In one embodiment, the alkaline ph. is a slightly a±kaline nfL In one embodiment, the aikal inc ph is the highest ph that doe.s not promote damage to the the as--ide and the alkyne during their contacting with a source of copper (I) ions.

In one embodiment, an azide and an alkyne are contacted with a source of copper(I) ions in the pres-ence of a chelator molecule according to the invention or with a copper complex according to the invention.

S In one embodiment, an azide and an alkyne are contacted with a source of coppertll) in the presence of a chelator molecule according to the invention or with a copper complex according to the invention in the absence of a further reducing agent capable of re-ducing copperCil) to copper(I) In one embodiment, an azide and an alkyne are contacted with a source of coppertli) in the presence of a chelator molecule according to the invention or with a copper complex according to the invention in the absence of a reducing agent capable of reducing copper(II) to copper(I) in alkaline pH.

In one embodiments an azide and an a].kyne are contacted with a source of copper(I) in the presence of a chelator molecule according to the invention or with a copper complex according to the invention in the absence of a further reducing agent capable of re-ducing copper(II) to copper (I).

In one embodiment, an azide and an alkyne are contacted with a source of copper(I) in the presence of a che.Lator molecule according to the invention or with a copper complex according to the invention in the absence of a further reducing agent capable of re-ducing copper(tI) to copperCl) in alkaline pH.

In one embodiment, the method comprises the steps of step a) preparing a source of copperCl); and step b) contacting an azide and an alkyne with the source of copper(I) obtainable from step a) in the presence of a chelator molecule according to the invention.

Itt one embodiment, the method comprises the steps of step a) preparing a source of copper(I); step h) contacting the source of copper(I) obtainable from step a) with a chelator molecule ac-cording to the invention to prepare a copper complex; S and step c) contacting an azide and an alkyne with the copper complex obtainable from step b).

The present invention further relates to the use of a chelator molecule according to the invention or the copper complex according to the invention for promoting a copper(I)-catalysed azide-alkyne cycloaddition reaction.

The presence of reducing sugar units in the chelator molecule may provide several advantages. The chelator molecule or the copper complex according to the invention has the ability to accelerate a CuAAC reaction. The chelator molecule may modulate the reac- tivity of copper (I), and reducing sugar units may pro- vide optimal hydrophilic, steric and electronic prop-erties for chelating copper(I). Reducing sugar units also improve aqueous solubility of the chelator mole- cule and the copper complex, thus allowing CuAAC reac-tions in aqueous solutions and in conditions that ate suitable for sensitive biomolecules such as proteins.

The chelator molecule is able to effectively bind cop-per ions and remove them from the solution e.g. after CuAAC reaction in aqueous solution.

The present inventions have also surprisingly found that the chelator molecule and copper complex according to the invention have the ability to protect biomolecules from copper-induced damage in a CuAAC re-action performed in aqueous solution. The chelator molecule and copper complex according to the invention are thus well suitable for a CuAAC reaction, wherein the azide or the alkyne present in the reaction com-prises a protein or other biomolecule. Furthermore, the chelator molecule and copper complex according to the invention have the ability to reduce copper(II) ions into the catalytically active copper(I) ions and sustain reducing conditions in the solution: thereby they may be able to remove the need to use an external reducing agent such as ascorbic acid. Furthermore, re-ducing sugar units are inexpensive, non-toxic and readily available for chelator molecule synthesis.

The embodiments of the invention described hereinbefore may be used in any combination with each other. Several of the embodiments may be combined to-gether to form a further embodiment of the invention.

A product, or a use, or a method to which the inven- tion is related, may comprise at least one of the em-bodiments of the invention described hereinbefore.

Efl1WLES In the followings the present invention will be described in more detail. Reference will now be made in detail to the embodiments of the present in- vention, examples of which are illustrated in the ac-companying drawings. The description below discloses some embodiments of the invention in such detail that a person skilled in the art is able to utilize the in-vention based on the disclosure. Not all steps of the embodiments are discussed in detail, as many of the steps will be obvious for the person skilled in the

art based on this specification.

EXAMPLE 1. Synthesis of TGTA.

General experimental details: Reagents and solvents were purchased from commercial sources. Reac-tion solvents were dried and distilled prior to use when necessary. All reactions containing moisture-or air-sensitive reagents were carried out under an argon atmosphere. The preparation of 1. has been described previously and similar routes were employed in the current synthesis (see for example Yanq, 3, , et. al. 20:03. 3, 3, Orq. let:.52223--6) the NMR spectra were recorded with a Bruker hvance spectrometer operating at 600 Mi-lz(H 600 MHz, C; 150 MHz) . PulsE: secjuc.ces provided by the manufac--turer were utilized. The or abe temperature riurna the exe rinrrs was kept at 22 C unless otherwi se. inen-tioned. Chemi.ca.1 shifts are expressed on the 6 scale.

(in ppm) using TMS (tetramethyisilane) residual chio roform, acetone., 1-1,0 or methanol as internal stan---dards. Coupling constants are aiven i.n Hz and provided only once when first encountered. Coupling patterns are given as s sinolet, d, doublet, t, triplet etc. Mass spectra were obtained with a Eruker Ultraf..lex III.

MAL0.tlOF mass spectrometer operated in posi---tive/negat:i xe mode. TLC was performed on aluminium sheets precoated with silica gel $0 E254 (Merck) -Flash chromatography was carried out on silica gel 50 (0.040-0. 060:wm Aldrich) -Spot:s were visualized by [N followed by charrino with 1 5.HS0/Me0Fi and heating.

HO

N,. -N / N F 9_OH N o 4o /=\ HO'J,'° NN of r-N' HO HO " N9 2:3 Schn 1. U Tripropargylamine, 0u304, sodium L-ascorbate, DP4F:H,0-3:1, Rr, 40h, quantitative; ii) 60% TFA (in H20) $0C, 25h, quantitative.

Protected TGTA (2): To a solution containing 43mg of 1 (0.lSmmol, 5 equiv..) and 4..Bpl tripropargylamine (O.O3mmol, 1 equiv.) in 2nd of DMF:H20 (3:1) was added 2.4mg CuSO4 (O.Oi5mmol, 0.5 equiv.) and 6.4mg sodium L-ascorbate (0.O3mmol, 1 equiv.). The resulting mixture was stirred at RT for 40h (during this time a white solid precipitated from the reaction mixture). After 40h, the reaction mixture was diluted with 20m1 EtOAc transferred to a separa- tory funnel and washed with Sm! NH4C1-solution (pre-pared by dissolving a saturated NH4CI-solution with equal amount of water 1:1 v/v) and lSml brine. The or- ganic phase was dried with Na2S04, filtered and concen-trated to give the crude product. The crude product was purified by column chromatography (EtOAc-.BtOAc:MeOH 3:1) to give 2 as a colorless oil (30mg, quantitative). TLC: R, = 0.22 (EtOAc). H NMR (600MHz, COd3, 25°C): 6 8.56 Cs, 3 H, triazole-H), 5.48 (d, 3 H, J),2 = 5.0Hz, H1), 4.67 (dd, 3 H, Ga,S 3.1, Ge.Gb = 14.1Hz, H-6a), 4.65 (dd, 3 H, J31 2.5, 8.1, H-3), 4.58 (dd, 3 H, J55 = 9.0Hz, H-6b), 4.41 and 4.33 (each d, each 3 H. wcu2a,ucH2b 14.1Hz, N(C112)3), 4.32 (dd, 3 H, 13-2), 4.25 (dcl, 3 H, J4,5 1.4Hz, 13-4), 4.17 (ddd, 3 11, H-S), 1.50, 1.39, 1.37 and 1.25 (each s, each 9 13, 02C(CH,)2) ppm. HRMS: ca].cd. for C45H66N10O1Na (M+Na] 1009,46; found 1009.40.

TGTA (3): 33mg of 2 (0.O34mmol) was dissolved in 3m]. 60% TFA (in 1120) and stirred at 50°C for 1.5 hours. The reaction mixture was then diluted with Wa-ter, concentrated and dried under vacuum to give 3 as a white solid (25mg, quantitative, a: 2:3). selected NMR-data; 211 NMR (600MHz, D20, 25°C): 5 8.32 (s, 6 H (a and 13, 3 H each), triazole-if), 5.21 Cd, 3 H, J1,2= 3.9Hz, 11-la), 4.59 (a, 12 H ta and, 6 11 each), N(C112)3), 4.50 Cd, 3 H, J,,2 8.1Hz, H-1). HRt4S; ca].cd. for C27H42N10015Na (M+Na) 769.27; found 769.23.

EXAME'LE 2. Synthesis of copper chelators.

Preparation of various azide- functionalized reducing sugar units in either pro- tected or unprotected form have been described previ-ously and similar routes are employed in the synthesis of copper chelators from different reducing sugars (see e.g. 2-, 3-, 4-and 6-azidoaldohexoses: 1,3,4,6-tetra-O-acetyl-2-azido-2-deoxy-a--D-mannopyranoside, 1,2,4, 6-tetra-O-acetyl-3-azido-3-deoxy-a-D- mannopyranoside, 1,2,3, 6-tetra-O-acetyl-4-azido-4-deoxy-a-D-manno-pyranoside, 6-azido-6-deoxy-D-mannose and 1,2,3, 4-tetra-O-acetyl-6-azido-6-deoxy-a-D-mannopyranoside in Marchesan, S. and Macmillan, D., 2008. Chem. Commun. 36:4321-4323; 5-azicloaldopentoses: 5-azido-5-deoxy-D-arabinose and 1,2, 3-tri-O-acetyl-5-azido-S-deoxy-D-arabinose in Smellie, l.A., et al,., 2007. Org. Biomol. Chem. 5:2257-66; 9-azidosialic ac- ids: e.g. 5-acetamido-9--azido-3, 5, 9-trideoxy-D-glycero-D-galacto-2-nonulosonic acid in Han, S., et al., 2005. Nat. them. Biol. 1:93-7; and 6-azicloketohexoses: e.g. 6-azido-6-deoxy-D-tagatose in Jenkinson, S.F., et al., 2011. Org. Lett. 13:4064-7), Also, azido sugars such as t,3,4,6-tetra-0-acetyl-2- (2-azido) acetamido-2-deoxy-a-D-glucopyranoside and 1,3,4, 6-tetra-O-acetyl-2-(2-azido)acetamido-2-deoscy-u-D-galactopyranoside are available from e.g. Thermo Fischer Scientific (Pierce) When using a protected azide-functionalized reducing sugar unit, copper chelator is prepared ac-cording to Scheme 2:

N SA

I-

--N. N.

Z

Schete 2. 1) Couplina of protected sugar (Z SuqN3) to tr.propargylam1ne: Triproparqyiami.ne, LuSO sodium I--ascorbata, OME:.EUO 3:1, RT, 0/n; 1.1) Depro- tect±on of sugar unit: in case of acid labile protec-tire groups the following c' onditions are utilized; TEA:H,O g:.., 0°C-RT:, l-4h; :n case of base labile pro-tec tire groups the following conditions are utilized: NeOMe, MeCH, H10, PT, 4h-o/n; Sug sugar unit; 1 protected functioral groums of Sug; x unorotected runctjorAal groups of Sue.

When an unorot:ecLed azicie-functionali red re--ducing sugar unit is used, copper chelator is prepared accord.ng to Scheme 3: N.... ,Su N" K'

N

N >-)t--N Schete 3 l)T riproargy.lamine, CuSO, sodium lrasccrbate, tEuOH:H2C):OCM 3:3:1, PT, 0/n; Sug sugar unit; functional croupsof Sug.

EXAMPLE 3. Synthesis of TSTA, tris ( (1 (9 (N acetylneuraminyl) ) iHi, 2, :3triazoi---4-y:L) methyl) amine.

The preparation of 5 (Scheme 1) has been de-scribed pr:eviouslv and similar routes were employed in tecrrentsynthesJ..s (see rot example Han, S. , et al Nat. Chew, Sic!. 2005, 1, 93-97

HO

HO\ WHAc HO'K,

N -N

HO OH

H CO?H t-OH CO2H / 4 NHAt' N N JyoHJH AcHN c,. . HCi CO2H c Lb 00 H

OH

Scheme 4. ± ) 1) MeC)EU AG 50wX13 (}F form) 45C c/n, quantitative; 2) TsCI, pyridine, 0°C+RT, o/n, 67%; 3) NaN,, Acetone: H,?C 3:1, 75°C, a/n, 52%; ii) tripropa.rqv1Lar:Lne, Cu.504 * sodLum:u.ascorhate tBuC)(lcL)CM 3 3:1, RT 0/n.

5'acetamido9az.ido"3, 5, 9-trideox0-'glycer D-qa.iacto--2.--ncn.ulosoni c acid (5) : To a so1ui on corn-taming 63mg of 4 (0. 2runol) in Sm! dry MeOb (under ar gon) was added 127mg AC SOWX3 (2 weight equivalents) and the resulting m:L.xt:ure was stirred at 45°C c/n, The mixture was then filtered and concentrated to give.me--thy! I&acetyl neuraminate as a whites did (65mg, quantitatIve). TIC: Rf= 0.43 (DCM:MeOH 31) 157mg of methyl Nacetyl neuraminate (0. 49rmnoi) was dissolved in Sm! of dry pyridine (under argon) end the reaction mixture was cooled to 0°C, ISSmo Tad (0, 7mmo.1, 1.4 eauivaients) was added and the reaction mixture was slowly warmed to RT and left to stir o/nAf tar 23 nours 134mg TSC1 (0. 7zrmol, 1.4 equivalents) was added to the reaction mixture and it was stirred for an additional 2 hours at IC. The mix-ture was then cooled to 0°C and the reaction quenched with t4eOH. The mixture was concentrated and the crude product was purified by column chromatography (MeOH:DCM 1:9) to give methyl 9-O-tosyl-N-acetyl-neuraminate as a yellowish oil (159mg, 67%). TLC: R1 0.29 (DCM:MeOH 9:1). H NMR (600MHz, CD3OD, 22°C): 8 Selected NMR-data; 7.80-7.43 Cm, 4 H, CH3C6H4S02),4.28 (dd, 1 H, J = 2.2, 10.1 Hz),4.06-3.99 Un, 2 H), 3.93 (dd, 1 H, J 1.5, 10.6 Hz),3.85 (ddd, 1 H, J 2.0, 5.7, 8.5 Hz),3.77 (a, 3 H, C02C113),3.43 (dd, 1 H, J 1.5, 9.0 Hz), 2.46 Cs, 3 H, CH3C6H4SO2), 2.19 (dd, 1 H, J = 49, 12.9 Hz, H-3eq), 2.00 (a, 3 H, NHCOCE3), 1.86 (dd, 1 H, J 11.5, 12.9 Hz, H-3ax). }3RMS: calcd. for C19H27O13NNaS (M+Na]' 500.12; found 500.20.

110mg of methyl 9-O-tosyl-N-acetyl- neuraxainate (0.23cnmol) was dissolved in 2m1 ace-tone:H20 3:1 and 70mg NaN3 (1.lmmol, 4.3 equva1ents) was added. The resulting mixture was heated to 75°C and stirred o/n. The reaction mixture was then concen- trated and the crude product purified by gel filtra-tion chromatography to give 5 as a yellowish foam (40mg, 52%). Selected NMR-data; H NMR (600MHz, D20, 22°C): 5 4.03 (ddd, 1 H, J= 5.1, 10.1, 10.3 Hz), 3.99 (dd, 1 H, J = 0.9, 10.6 Hz), 3.94-3.89 Cm, 2 H), 3.61 (dd, 1 H, .J 2.8, 13.1 Hz), 3.53 Cap ci, 1 H, J = 9.4 Hz),3.49 (dd, 1 H, J' 6.0, 13.1 Hz), 2.22 (dci, 1 H, J 4.9, 12.9 Hz, H-3eq), 2.07 (a, 3 H, NHCOCK3), 1.83 (dd, 1 H, J = 11.7, 12.9 Hz, H-3ax). HRMS: calcd. for CiHxqOeN4Na [M+Nar 357.10; found 357.12; calcd. for C11H17O0N4Na2 (M+2Na-H J 379.0$; found 379.10.

TSTh (6): 18.5mg of 5 (0.O55mmol, 4 equiva-lents) was dissolved in 3m1 tBuOH:H20:DCM 3:3:1. To the mixture was next added 2jal tripropargylamine (0.Ol4mmol, 1 equivalents), 1mg Cu504 (0.OO7mmol, 0.5 equivalents) and 3mg sodium L-ascorbate (0.Ol5xvunol, 2:, I. 1 equivalents) The reaction mixture was stirred f-or n/ri at PT and concentrated to dye the or ude product.

The crude product was purlf.Led byqei. gilti-ation ch:rc matogranhy to give 6 as a yellowish oil 4.6 mc, 29%) S Selected NMR-data; H NMR (600MHz, 0,0, 22'C) 5 8.00 (s, 3d, triazol i-f),4,79 (4, 3 Hf 3 14.1 Hz),4.51 (dd, 3 H, 7.8, 14.1 hz),4.12 (Odd, 3 H, J 2.6, 8.0, 8.3Hz), 4.02 (dOd, 3 H, Jr.: 4,9, 10.2, 11,1 Hz), 3.98 (0, 3 H, 3 10.9 Hz), 3.92 (4, 3 H, J 10.2 Hzh3,Bl (hr s, 6 H), 3.40 (d, 3 H, J 9.1 Hz), 2.22 (dd, 3 H, Cr = 4.9, 13.0 Hz, H3eg), 1.99 us, 9 1-1, NHC:0C:lh), 1.134 (dO, 3 Hf J 11.1, 15.0Hz, &h-3ax).

HRMS calcd. for 0FL202,N:i [M---H] 1:1:32.40; found 3. :i. 32.47 1.5 EXAMPLE 4, Svnthes± s of: f:itroblast: growth factor con-I ustes SOpg ( Snmol) of recombinant human basic fi--nroriLast growtH rector ( eproLec:h; Eur) in 5mM sodium 2.0 phosphate buffer pH 7,3 (SOul) was incubated wit.h 1.

molar excess (l2nmoi) of NF1SPEGrN:. (Life Technolo-gies; delivered in 3h1 dimethylsulphoxide (DM30) for 3 hours at: room i:emne:rat:ure. No reacted NHS'PEGgN was separated by Amicon centrifugal filter unit (Mil-lipore; 101< cut-off) . According to MALDI-TOF mass soectr omet c an.alys.i, on average 3-4 NH.S-PEG4-N molecules were attached to one FGF molecule (average molecular weight 184000a) qalactose conjugates were made by azide-- alkyne cycloaddition reaction. Three parallel reac-Lions were per formed to comoare the performance of two copper (1) ion chelators, TGTA andi T.BTh, and 1(2055 a control 10Th (A) , TBTA (B) and H70 (C) (A) To the solution of 0. 59naiol or in 25mM sodium. phosphate buffer pH 7,3 (22.gll and 15 molar excess of EHproparayl-D-galactose in F1O (0, Spi.) , 3 molar excess of CuS0 in lUG (0,-SpI) 15 mc---- lar excess of sodium ascorbate in 1320 (0,Sul), 7,5 mo*- lar excess of TGTA in H20 (0,Spl) and ipi of 0,514 so-dium phosphate buffer pH 7.3 were added. Total volume of the reaction was 25p1.

(B) To the solution of 0.S9nmol of EGF-PEG4-N3 in 25mM sodium phosphate buffer pH 7.3 (22pl) and 15 molar excess of 6-propargyl-D-galactose in H20 (O,Sul), 3 molar excess of CuSO4 in 1320 (0,Spl), 15 no- lar excess of sodium ascorbate in (O,5p1), 7,5 no- lar excess of TBTA in DM50 (0,54) and 1.zl of 0,5t4 so-dium phosphate buffer p13 7.3 were added. Total volume of the reaction was 25111.

(C) To the solution of 0.S9nmol of FGF-PEG4-N3 in 25mM sodium phosphate buffer pH 7.3 (22il) and 15 molar excess of 6-propargyl-D-galactose in H2° (O,5il), 3 molar excess of CuSO4 in 1320 (0,54), 15 mo-lar excess of sodium ascorbate in 2° (0,Siil), 0,54 of 1320 and lii]. of 0,5M sodium phosphate buffer pH 7.3 were added. Total volume of the reaction was 254.

Reactions A, B and C were incubated at room temperature for 20 hours. In the reactions A (with TGTA) and C (20) the solutions were clear (without any visible precipitates) after 20 hour incubation, but in reaction B (with TBTA) a precipitate was de-t.ected already after 0.5 hour incubation, The reactions were stopped and the FGF-galactose conjugates purified by Amicon centrifugal filter units (101<).

Characterization of the reaction products was performed as follows: lOp! of Sx Laemmli sample buffer was added to all three 1micon-purified reactions (A, B and C, 404 each) and the samples were boiled for S win. A FGF-PEG4-N3 sample (pg) was prepared similarly.

The samples were run on 4-15% gradient SOS-PAGE gel (tliniProtean TGX gels, BioRad) using Spectra Broad Range Protein Ladder (Fermentas) as a molecular weight standard. The gel was stained with Imperial Protein Stain (Thermo Scientific) according to manufacturer's instructions. Ira the stained SOS-PAGE gel the FGF- PEG4-N3 appeared as 18.4kDa size band. The FGF-galactose conjugate from Sample A appeared as 19.1 kDa size band, showing that the reaction had proceeded as expected. No smaller size bands were detected in these two samples, showing that no degradation products were detectable in Sample A. No protein bands were detected in sample C, showing that the protein was degraded in a CuAAC reaction performed without a chelator mole- cule. These results show that the conjugation of ga- lactose to FGF-PEG4-N, was successftzl only in the pres- ence of TGTA and propargyl-modified galactose was ef-ficiently conjugated to azide-modified FGF in these conditions.

As is clear for a person skilled in the art, the invention is not limited to the examples and em-bodiments described above, but the embodiments can freely vaxy within the scope of the claims.

Claims (38)

1. CLAIMS1. A chelator molecule represented by formulaIFormula I wherein each of R1, R2 and R3 is independently selected from the group consisting of a reducing sugar unit, C-C alkyl, C3C9 carbocyclyl, aryl, C-0 alkyl-aryl, alkyl-(03-08 carbocyclyl), C3C heterocyclyl, 01-08 alkyl-(03-08 heterocyclyl), and H; with the proviso that at least one substitu-ent selected from R1, R2 and R3 is a reducing sugar unit.
2. 2. The chelator molecule according to claim 1, wherein at least two substituents selected from R1, R2 and R3 are reducing sugar units.
3. 3. The chelator molecule according to claim 1 or 2, wherein each substituent selected from R1, R2 and R3 is a reducing sugar unit.
4. 4. The chelator molecule according to any one of claims 1 -3, wherein the reducing sugar unit com- prises a reducing monosaccharide, a reducing disaccha- ride, a reducing oligosaccharide, or a reducing poly-saccharide.
5. 5. The chelator molecule according to any one of claims 1 -4, wherein at least one substituent se-lected from R1, R2 and R3 is a reducing monosaccharide.
6. 6. The chelator molecule according to any one of claims 1 -5, wherein at least two substituents se-lected from R1, R2 and R3 are reducing monosaccharides.
7. 7. The chelator molecule according to any one of claims 1 -6, wherein each substituent selected from R1, R2 and R3 is a reducing monosaccharide.
8. 8. The chelator molecule according to any one of claims 4 -7, wherein the reducing monosaccharide is in the D-or L-configuration.
9. 9. The chelator molecule according to any one of claims I -8, wherein the reducing monosaccharide is represented by formula II x5 Formula II wherein X' is either OH, H, hydroxymethyl, methyl, carboxyl, substituted carboxyl, 01-06 alkyl or 1 is either absent or CH(X4); X2, X3, X4 and X5 are each independently either OH, H, amino, C1C6 alkylamine, 0106 alkylether, C1C6 alkylester, halogen, mercapto, C2C6 acylamide, carbox-yl, substituted carboxyl, C1C6 alkyl, substituted Cl-CE alkyl, phosphate ester, sulphate ester, or a bond to the tris (triazolylmethyl) amine group; with the proviso that one substituent se-lected from X2, X3, X4 and X5 is a bond to the tris(triazolylmethyl)amine group, or X2, X3, X4 or X5 is bonded via a bond to the tris(triazolylmethyl)amine group.
10. 10. The chelator molecule according to claim 9, wherein X5 is OH, H, amino, Cl-CE alkylamine, 01-06 alkylether, C1C6 alkylester, halogen, mercapto, 02-CE acylamide, carboxyl, substituted carboxyl, C1C6 alkyl, substituted C1O6 alkyl, phosphate ester, or sulphate ester; and is bonded via a bond to the tris (triazolylmethyl)amine group.
11. 11. The chelator molecule according to claim 9 or 10, wherein Y is CH(X4); and X2, X3 and X4 are each independently either OH or H.
12. 12. The chelator molecule according to claim 9 or 10, wherein Y is absent; and X2 and X3 are each independently either OH or H.
13. 13. The chelator molecule according to any one of claims 4 -11, wherein the reducing monosaccha-ride is an aldohexose represented by formula III CH2HO OH

    HO OH

    Formula III wherein OH2 is bonded via a bond to the tris (triazolylmethyl) amine group.
14. 14. The chelator molecule according to claim 13, wherein the aldohexose is selected from the group consisting of 0-and L-forms of allose, altrose, glu-cose, mannose, gulose, idose, galactose and talose.
15. 15. The chelator molecule according to claim 13 or 14, wherein the aldohexose is selected from the group consisting of 0-glucose, 0-galactose and 0-mannose.
16. 16. The chelator molecule according to any one of claims 1 -15, wherein the chelator molecule is selected from the group consisting of tris{[l-(6-D-galactosyl) -lB-i, 2, 3-triazol-4-yl]methyl}amine, tris{ [1-(6-D-glucosyl)-1H-1,2,3-triazol-4- yl]methyl}amine and tris{[1-(6-D-mannosyl)-1H-1,2,3-triazol-4-yl] methyl} amine.
17. 17. The chelator molecule according to any one of claims 4 -8, wherein the reducing monosaccha-ride is sialic acid.
18. 18. The chelator molecule according to any one of claims 1 -17, wherein R1 = R2 = 19. A copper complex comprising a chelator molecule according to any one of claims 1 -18 complexed with a copper ion.20. The copper complex according to claim 19, wherein the copper ion is a copper(I) ion.21. The copper complex according to claim 19, wherein the copper ion is a copper(II) ion.22. A kit comprising a chelator molecule ac- cording to any one of claims 1 -18 or a copper com-plex according to any one of claims 19 -21.23. The kit according to claim 22, wherein the kit further comprises a source of copper(I) 24. The kit according to claim 22 or 23, wherein the kit further comprises a source of cop-per (II) 25. The kit according to any one of claims 22 -24, wherein the kit further comprises a reducing agent capable of reducing copper(II) to copper(I) 26. The kit according to claim 25, wherein the reducing agent capable of reducing copper(II) to copper(I) is selected from the group consisting of ascorbate, quinone, hydroquinone, vitamin 1<1, gluta-thione, cysteine, Fe2, Co2, and an applied electric potential; or is a metal selected from the group con-sisting of Cu, Al, Be, Co, Cr, Fe, Mg, Mn, Ni, and Zn.27. A method for preparing the chelator mole-cule according to any one of claims 1 -18, which method comprises the step of reacting an azide-functionalised reducing sugar unit with tripropargylamine.28. The method according to claim 27, wherein an azide-functionalised reducing sugar unit is reacted with tripropargylamine in the presence of a source of copper(I) 29. The method according to claim 27 or 28, wherein the azide-functionalised reducing sugar unit is protected by a protecting group.30. The method according to claim 29, wherein the method further comprises the step of deprotecting the azide-functionalised reducing sugar unit.31. The method according to any one of claims 27 -30, wherein the azide-functionalised reducing sugar unit is an azide-functionalised reducing mono-saccharide.32. The method according to any one of claims 27 -31, wherein an azide-functionalised reducing sug- ar unit is reacted with tripropargylamine in the pres-ence of a source of copper(II) ions and a reducing agent capable of reducing copper (II) to copper(I) 33. The method according to claim 32, wherein the reducing agent capable of reducing copper(II) to copperCi) is selected from the group consisting of ascorbate, quinone, hydroquinone, vitamin Ri, gluta-thione, cysteine, Fe2, Co2, and an applied electric potential; or is a metal selected from the group con-sisting of Cu, Al, Be, Co, Cr, Fe, Mg, Mn, Ni, and Zn.34. A method for promoting a copper(I)-catalysed azide-alkyne cycloaddition reaction, wherein the method comprises contacting an azide and an alkyne with a source of copper ions in the presence of a chelator molecule according to any one of claims 1 - 18 or with a copper complex according to any one of claims 19 -21.35. The method according to claim 34, wherein an azide and an alkyne are contacted with a source of copper ions in the presence of a chelator molecule ac-cording to any one of claims 1 -18 or with a copper complex according to any one of claims 19 -21 in aqueous solution.36. The method according to claim 34 or 35, wherein an azide and an alkyne are contacted with a source of copper ions in the presence of a chelator molecule according to any one of claims 1 -18 or with a copper complex according to any one of claims 19 - 21 in alkaline pH.37. The method according to any one of claims 34 -36, wherein an azide and an alkyne are contacted with a source of copper(II) ions in the presence of a chelator molecule according to any one of claims 1 - 18 or with a copper complex according to any one of claims 19 -21 and in the presence of a reducing agent capable of reducing copper(II) to copper (I) 38. The method according to claim 37, wherein the reducing agent capable of reducing copper(II) to copper(I) is selected from the group consisting of ascorbate, quinone, hydroquinone, vitamin Kl, gluta-thione, cysteine, Fe2, Co2, and an applied electric potential; or is a metal selected from the group con-sisting of Cu, Al, Be, Co, Cr, Fe, Mg, Mn, Ni, and Zn.39. The method according to any one of claims 34 -38, wherein an azide and an alkyne are contacted with a source of copper(I) ions in the presence of a chelator molecule according to any one of claims 1 - 18 or with a copper complex according to any one of claims 19 -21.40. The method according to any one of claims 34 -36 or 39, wherein an azide and an alkyne are con-tacted with a source of copper(I) or copper(II) in the presence of a chelator molecule according to any one of claims 1 -18 or with a copper complex according to any one of clams 19 -21 in the absence of a further reducing agent capable of reducing copper(II) to cop-per(I) 41. The use of a chelator molecule according to any one of claims 1 -18 or a copper complex ac-cording to any one of claims 19 -21 for promoting a copper (I) -catalysed azide-alkyne cycloaddition reac-tion.Amendments to the claims have been filed as followsCLAIMS1. A chelator molecule represented by formula E'ormula I wherein each of R, R2 and 1k3 is independently selected from the group consisting of a reducing sugar 0) 10 unit, C1*-C8 alkyl, C3-C8 carbocyclyl, aryl, Cj-C8 alkyl- aryl, Cl-Ca alkyl-(C3-C8 carbocyclyl), C3-C9 heterocy-clyl, C1-C8 alkyl-(C3-Ca heterocyclyl), and B; B with the proviso that at least one substitu-ent selected from P1, R2 and R3 is a reducing sugar unit; 0 2. The chelator molecule according to claim 1, wherein at least two substituents selected from Ri, 1k2 and R3 are reducing sugar units.3. The chelator molecule according to claim 1 or 2, wherein each substituent selected from R1, R2 and R3 is a reducing sugar unit.4. The chelator molecule according to any one of claims 1 3, wherein the reducing sugar unit com- prises a reducing monosaccharide, a reducing disaccha- ride, a reducing oligosaccharide, or a reducing poiy-saccharide.5. The chelator molecule according to any one of claims 1 -4, wherein at least one substituent se-lected from Rj, R2 and R3 is a reducing monosaccharide4 6. The chelator molecule according to any one of claims 1 -5, wherein at least two substituents se-lected from R, R and 1k3 are reducing monosaccharides.7. The chelator molecule according to any one of claims 1 -6, wherein each substituent selected from R1, R2 and R3 is a reducing monosaccharide.8. The chelator molecule according to any one of claims 4 -7, wherein the reducing monosaccharide is in the D-or L-configuration.9. The chelator molecule according to any one of claims 4 -8, wherein the reducing monosaccharide is represented by formula II xs Formula II wherein X1 is either OH, H, hydroxymethyl, O methyl, carboxyl, substituted carboxyl, C1-C6 alkyl or Y is either absent or CH(X4); X2, X3, X4 and x5 are each independently ei-ther OH, H, amino, C1-C6 alkylamine, C1-C5 alkylether, Ct-C6 alkylester, halogen, mercapto, C-C6 acylamide, carboxyl, substituted carboxyl, C1-C5 alkyl, substitut-ed C1-C6 alkyl, phosphate ester, sulphate ester, or a bond to the tris(triazolylmethyl)amine group; with the proviso that one substituent select-ed from X2, X3, X4 and X5 is a bond to the tris(triazolylmethyl)amine group, or X2, X3, X4 or is bonded via a bond to the tris(triazolylmethyl)amine group.10. The chelator molecule according to claim 9, wherein X is OH, H, amino, C1-C5 alkylamine, C1-C6 11. alkylether, CrC6 aikylester, halogen, mercapto, C2-C6 acylamide, carboxyl, substituted car-boxyl, Cs-Ce alkyl, substituted C1-C6 alkyl, phosphate ester, or sulphate ester; and is bonded via a bond to S the tris(triazolylmethyl)amine group.12. The chelator molecule according to claim 9 or 10, wherein 1 is CH(X'}; and X2, X3 and X4 are each independently either OH or H. 13. The chelator molecule according to claim 9 or 10, wherein Y is absent; and X2 and X3 are each independently either OH or H. 14. The chelator molecule according to any one of claims 4 -11, wherein the reducing monosaccha--ride is an aldohexose represented by formula III OH2COi--HO OHN-HOOM° Formula III O wherein C)!2 is bonded via a bond to the tris (triazolylmethyl) amine group.15. The chelator molecule according to claim 13, wherein the aldohexose is selected from the group consisting of D-and fr-forms of allose, altrose, glu-cose, mannose, gulose, idose, galactose and talose.16. The chelator molecule according to claim 13 or 14, wherein the aldohexose is selected from the group consisting of D-glucose, D-galactose and D-mannose.17. The chelator molecule according to any one of claims 1 -15, wherein the chelator molecule is selected from the group consisting of tris{(l-(6--D--galactosyi)-1H-1,2, 3-triazol-4-yl]methyl}amine, tris{ (l-(6-D-giucosyl)-1H-l,2,3-triazol-4- y1]methy1,amine and tris{(1-(6-D-mannosyl)-1H-1,2,3-triazol-4-yl]methyl} amine.18. The chelator molecule according to any one of claims 4 -8, wherein the reducing monosaccha-ride is sialic acid.
19. 19. The chelator molecule according to any one of claims 1 -17, wherein R1 = =
20. 20. A copper complex comprising a chelator molecule according to any one of claims 1 -18 corn-plexed with a copper ion.
21. 21. The copper complex according to claim 19, wherein the copper ion is a copper(I) ion.
22. 22. The copper complex according to claim 19, wherein the copper ion is a copper(IX) ion.
23. 23. A kit comprising a chelator molecule ac- cording to any one of claims 1 -18 or a copper com- ___ plex according to any one of claims 19 -21, wherein the kit comprises a source of copper(I), wherein the kit comprises a source of copper(IT), and wherein the kit comprises a reducing agent capable of reducing copperill) to copper(t).0
24. 24. The kit according to claim 22, wherein the reducing agent capable of reducing copper(tI) to copper(I) is selected from the group consisting of ascorbate, quinone, hydroquinone, vitamin Ml, gluta-thione, cysteine, Fe2, Co2, and an applied electric potential; or is a metal selected from the group con-sisting of Cu, Al, Be, Co, Cr, Fe, Mg, Mn, Ni, and Zn.
25. 25. A method for preparing the chelator mole-cule according to any one of claims 1 -18, which method comprises the step of reacting an azide- functionalised reducing sugar unit with tripropargyla-mine.
26. 26. The method according to claim 24, wherein an azide-functionalised reducing sugar unit is reacted with tripropargylamine in the presence of a source of copper(I).
27. 27. The method according to claim 24 or 25, wherein the azide-functionalised reducing sugar unit is protected by a protecting group.
28. 28. The method according to claim 26, wherein the method further comprises the step of deprotecting the azide-functionalised reducing sugar unit.
29. 29. The method according to any one of claims 24 -27, wherein the azide-functionalised reducing sugar unit is an azide-functionalised reducing mono-saccharide.
30. 30. The method according to any one of claims 24 -28, wherein an azide-functionalised reducing sug- ___ ar unit is reacted with tripropargylamine in the pres-C ence of a source of copper(II) ions and a reducing agent capable of reducing copper(II) to copper(t).O 20
31. 31. The method according to claim 29, wherein the reducing agent capable of reducing copper(II) to O copper(I) is selected from the group consisting of ascorbate, quinone, hydroquinone, vitamin Ki, gluta-thione, cysteine, Fe2, Co2, and an applied electric potential; or is a metal selected from the group con-sisting of Cu, Al, Be, Co. Cr, Fe, Mg, Mn, Ni, and Zn.
32. 32. A method for promoting a copper(I)-catalysed azide-alkyne cycloaddition reaction, wherein the method comprises contacting an azide and an alkyne with a source of copper ions in the presence of a che-lator molecule according to any one of claims 1 -18 or with a copper complex according to any one of claims 19 -21.
33. 33. The method according to claim 31, wherein an azide and an alkyne are contacted with a source of copper ions in the presence of a chelator molecule ac-cording to any one of claims 1 -18 or with a copper complex according to any one of claims 19 -21 In aqueous solution.
34. 34. The method according to claim 31 or 32, wherein an azide and an alkyne are contacted with a source of copper ions in the presence of a chelator molecule according to any one of claims 1 -18 or with a copper complex according to any one of claims 19 - 21 in alkaline pH.
35. 35. The method according to any one of claims 31 -33, wherein an azide and an alkyne are contacted with a source of copper(II) Ions in the presence of a chelator molecule according to any one of claims 1 -CO 18 or with a copper complex according to any one of claims 19 -2]. and in the presence of a reducing agent N-capable of reducing copperClt) to copper(I).O 20
36. 36. The method according to claim 34, wherein the reducing agent capable of reducing copper(II) to O copper (I) is selected from the group consisting of ascorbate, quinone, hydroquinone, vitamin Ki, gluta-thione, cysteine, Fe23, Co2, and an applied electric potential; or is a metal selected from the group con-sisting of Cu, Al, Be, Co, Cr, Fe, Mg, Mn, Ni, and Zn.
37. 37. The method according to any one of claims 31 -35, wherein an azide and an alkyne are contacted with a source of copper(I) ions in the presence of a chelator molecule according to any one of claims 1 - 18 or with a copper complex according to any one of claims 19 -21.
38. 38. The method according to any one of claims 31 -33 or 36, wherein an azide and an alkyne are con-tacted with a source of copper(I) or :39. copper(lI) in the presence of a chelator molecule according to any one of claims 1 -18 or with a copper complex according to any one of claims 19 - 21 in the absence of a further reducing agent capable of reducing copper(II) to copperCl).40. The use of a chelator molecule according to any one of claims 1 -lB or a copper complex ac-cording to any one of claims 19 -21 for promoting a copper(I)-catalysed azide-alkyne cycloaddition reac-tion.CON