Coumarin-metal complexes and uses thereof

Abstract

Compounds of Formula (I) are described, in which: R1 to R6 are each, independently, selected from H, Z1-PEG and Z2-A-Mn+; Z1 and Z2 are each, independently, a linker; A is selected from the group consisting of a carboxylate group, a hydroxymate group, or a hydrazine group (C(O)NH-NH2); Mn+ is a metal ion selected from Zn2+, Sn2+, Cu2+, Cu+, Cd2+, Cr2+, Cr3+, Pt2+, Pt4+, Ni2+ Pb2+, Pd, Ru2+, Rd, Au+, Au3+ Ag+, Mn2+, Hg2+, Co+, Co2+, Co3+ Fe2+, or Fe3+ in which the metal ion is coordinated to one of more ligands to complete its coordination sphere; P+ designates the charge on the complex ion which may be positive, negative, or absent; and B is a counterion; in which one of R1 and R2 is one of Z1-PEG and Z2-A-Mn+ and one of R3, R4, R5, or R6 is another of Z1-PEG and Z2-A-Mn+.

Description

[0001] TITLE

[0002] Coumarin-metal complexes and uses thereof

[0003] Field of the Invention

[0004] The present disclosure relates to coumarin-metal complexes with improved physiochemical properties, methods of preparation of such coumarin-metal complexes and methods of use thereof.

[0005] Background of the Invention

[0006] A Lancet publication of 2022 attributed 1.2 million global deaths in 2019 to antimicrobial resistance (AMR). AMR is identified as one of the top-ten global human health threats in modem times. Now being dubbed as the silent pandemic, there is an urgent need for the development of novel antimicrobial therapies to combat this ever- growing threat to global human health. Coumarins are naturally occurring heterocyclic compounds representing a privileged chemical scaffold for the design and synthesis of pharmacologically active compounds and are ideal candidates for the development of novel antimicrobial therapies. However, their innate insolubility in aqueous solutions is a known limitation which hinders their development as much needed therapeutics.

[0007] It is an object of the invention to overcome at least one of the above-referenced problems.

[0008] Summary of the Invention

[0009] In a first aspect, the invention provides a compound of Formula (I):

[0010]

[0011] Formula (I) in which:

[0012] R1to R6are each, independently, selected from any substituent, H, Zi-PEG and Z2-A- Mn+;

[0013] Z1 and Z2 are each, independently, a linker;

[0014] A is selected from the group consisting of a carboxylate group, a hydroxamate group, or a hydrazine group (C(0)NH-NH2);

[0015] Mn+is a metal ion selected from Zn2+, Sn2+, Cu2+, Cu+, Cd2+, Cr2+, Cr3+, Pt2+, Pt4+, Ni2+Pb2+, Pd, Ru2+, Rd, Au+, Au3+Ag+, Mn2+, Hg2+, Co+, Co2+, Co3+Fe2+, or Fe3+in which the metal ion is coordinated to one of more ligands to complete its coordination sphere;

[0016] P+ designates the charge on the complex ion which may be positive, negative, or absent; and

[0017] B is a counterion; in which one of R1and R2is one of Zi-PEG and Z2-A-Mn+and one of R3R4, R5, or R6is another of Zi-PEG and Z2-A-Mn+.

[0018] In any embodiment, Z1 and Z2 are each independently selected from aryl, alkyl, 0, NH, CH2, thiol, alkyl, lower alkyl, alkoxy, lower alkoxy, O-alkyl, CH2O, CH2NH, CO, and COO. In any embodiment, Zi and Z2 are 0.

[0019] In any embodiment, M+is selected from the group Zn2+, Sn2+, Cu2+, Cu+, Cd2+, Cr2+, Cr3+, Pt2+, Pt4+, Ni2+, Pb2+, Pd, Ru2+, Rd, Au+, Au3+Ag+, Mn2+, Hg2+, Co+, Co2+, Co3+Fe2+, or Fe3+.

[0020] In any embodiment, Z2-A-M+is -O-CH2-C(O)-O-M+.

[0021] In any embodiment, Z1-PEG is -O-(PEG)n, in which n is 1 to 5.

[0022] In any embodiment, R1is Z1-PEG and one of R3R4R5or R6is Z2-A-M+.

[0023] In any embodiment, R1is Z1-PEG and R6is Z2-A-IVF

[0024] In any embodiment, R1is Z2-A-M+and one of R3R4R5or R6is Z1-PEG.

[0025] In any embodiment, R1is Z2-A-M+and R6is Z1-PEG.

[0026] In any embodiment, the compound has antimicrobial activity.

[0027] In any embodiment, the compound is selected from the group consisting of: In any embodiment, Mn+is selected from Ag+and Zn2+.

[0028] In any embodiment, Mn+is Ag+.

[0029] In another aspect, the invention provides a composition comprising a compound of the invention. In any embodiment, the composition is selected from an antimicrobial or biocidal composition.

[0030] In any embodiment, the composition is used to inhibit the growth of at least one pathogenic bacterium for example a clinically relevant strain of Escherichia coli (E. coli), Methicillin-resistant Staphylococcus aureus (MRSA), or Pseudomonas aeruginosa.

[0031] In another aspect, there is provided a use of the composition or compound of the invention as a medicament.

[0032] In another aspect, there is provided a use of the composition or compound of the invention to treat a surface to kill or inhibit the growth of bacteria on the surface.

[0033] In another aspect, there is provided a pharmaceutical composition comprising a compound of the present invention in combination with a suitable pharmaceutical excipient.

[0034] In another aspect, there is provided a method of preventing a bacterial infection in a subject comprising a step of administering a therapeutically effective amount of a compound or composition of the present invention to the subject.

[0035] In any embodiment, the method comprises co-administering an anti-bacterial compound / composition or antibiotic to the subject.

[0036] In any embodiment, the infection is selected from a urinary tract infection, a surgical site infection, a skin infection, a lung infection, foot infection, diabetic wound infection, a central catheter-related blood circulatory infection, probe-related urinary system infections, bacteremia, secondary meningitis, and ventilator-associated pneumonia in hospital intensive-care units.

[0037] Brief Description of Figures

[0038] Figure 1. Minimum inhibitory concentrations of Silver(l) Coumarin complexes against R aeruginosa (PA01 ).

[0039] Figure 2. Minimum inhibitory concentrations of silver(l) coumarin complexes MRSA ATCC43300.

[0040] Figure 3. Minimum inhibitory concentrations of silver(l) complexes against E.coli ATCC25922.

[0041] Figure 4. NMR spectrum of 4-(mPEG)2-Coumarin-7-oxyacetoAg_light (D2O).

[0042] Figure 5. NMR spectrum of 4-(mPEG)2-Coumarin-7-oxyacetoAg_light (DMSO).

[0043] Figure 6. NMR spectrum of 4-(mPEG)2-Coumarin-7-oxyacetoAgTPP2_light (DMSO)

[0044] Detailed Description of the Invention

[0045] The following description and examples illustrate various embodiments of the present disclosure in detail. Those of skill in the art will recognize that there are numerous variations and modifications of this disclosure that are encompassed by its scope. Accordingly, the description of the disclosed embodiments should not be deemed to limit the scope of the present disclosure.

[0046] Definitions

[0047] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art. All patents, applications, published applications and other publications referenced herein are incorporated by reference in their entirety unless stated otherwise. In the event that there is a plurality of definitions for a term herein, those in this section prevail unless stated otherwise.

[0048] Unless otherwise required by context, the use herein the singular is to be read to include the plural and vice versa. The term “a” or “an” used in relation to an entity is to be read to refer to one of more that entity. As such, the terms “a” (or “an”), “one or more”, and “at least one” are used interchangeably herein.

[0049] The term “comprise”, or variations thereof such as “comprises” or “comprising”, are to be read to indicate the inclusion of any recited integer (e.g. a feature, element, characteristic, property, method / process step or limitation) or group of integers (e.g. features, element, characteristics, properties, method / process steps or limitations) but not the exclusion of any other integer or group of integers. Thus, as used herein the term “comprising” is inclusive or open-ended and does not exclude additional, unrecited integers or method / process steps.

[0050] As used herein, the term “disease” is used to define any abnormal condition that impairs physiological function and is associated with specific symptoms. The term is used broadly to encompass any disorder, illness, abnormality, pathology, sickness, condition or syndrome in which physiological function is impaired irrespective of the nature of the aetiology (or indeed whether the aetiological basis for the disease is established). It therefore encompasses conditions arising from infection, trauma, injury, surgery, radiological ablation, poisoning or nutritional deficiencies.

[0051] As used herein, the term "treatment" or "treating" refers to an intervention (e.g., the administration of an agent to a subject) which cures, ameliorates or lessens the symptoms of a disease or removes (or lessens the impact of) its cause(s). In this case, the term is used synonymously with the term “therapy”.

[0052] Additionally, the terms "treatment" or "treating" refers to an intervention (e.g., the administration of an agent to a subject) which prevents or delays the onset or progression of a disease or reduces (or eradicates) its incidence within a treated population. In this case, the term treatment is used synonymously with the term “prophylaxis”.

[0053] As used herein, an effective amount or a therapeutically effective amount of a compound of the invention defines an amount that can be administered to a subject without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit / risk ratio, but one that is sufficient to provide the desired effect, e.g. the treatment or prophylaxis manifested by a permanent or temporary improvement in the subject's condition. The amount will vary from subject to subject, depending on the age and general condition of the individual, mode of administration and other factors. Thus, while it is not possible to specify an exact effective amount, those skilled in the art will be able to determine an appropriate "effective" amount in any individual case using routine experimentation and background general knowledge. A therapeutic result in this context includes eradication or lessening of symptoms, reduced pain or discomfort, prolonged survival, improved mobility and other markers of clinical improvement. A therapeutic result need not be a complete cure.

[0054] In the context of treatment and effective amounts as defined above, the term subject (which is to be read to include "individual", "animal", "patient" or "mammal" where context permits) defines any subject, particularly a mammalian subject, for whom treatment is indicated. Mammalian subjects include, but are not limited to, humans, domestic animals, farm animals, zoo animals, sport animals, pet animals such as dogs, cats, guinea pigs, rabbits, rats, mice, horses, cattle, cows; primates such as apes, monkeys, orangutans, and chimpanzees; canids such as dogs and wolves; felids such as cats, lions, and tigers; equids such as horses, donkeys, and zebras; food animals such as cows, pigs, and sheep; ungulates such as deer and giraffes; and rodents such as mice, rats, hamsters and guinea pigs. In preferred embodiments, the subject is a human.

[0055] As used herein, the term “linker” refers to any linker group, including an aryl or alkyl group. Preferred linkers include 0, NH, CH2, S, alkyl, lower alkyl, alkoxy, lower alkoxy, O-alkyl, CH2O, CH2NH, CO, and COO. As used herein, the term “lower alkyl” refers to an alkyl group, but having from one to ten carbons, more preferably one to six carbon atoms in its backbone structure.

[0056] As used herein, the term “alkyl” refers to a group containing from 1 to 8 carbon atoms and may be straight chained or branched. An alkyl group is an optionally substituted straight, branched, cyclic saturated hydrocarbon group. When substituted, alkyl groups may be substituted with up to four substituents at any available point of attachment. When the alkyl group is said to be substituted with an alkyl group, this is used interchangeably with “branched alkyl group”. Exemplary unsubstituted such groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, isohexyl, 4, 4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl, dodecyl, and the like. Exemplary substituents may include but are not limited to one or more of the following groups: halo (such as F, Cl, Br, I), Haloalkyl 25 (such as CCh or CF3), alkoxy, alkylthio, hydroxyl, carboxy (-COOH), alkyloxycarbonyl (-C(O)R), alkylcarbonyloxy (- OCOR), amino (-NH2), carbamoyl (-NHCOOR-or-OCONHR), urea (-NHCONHR-) or thiol (-SH). Alkyl groups as defined may also comprise one or more carbon double bonds or one or more carbon to carbon triple bonds.

[0057] As used herein, the term “lower alkoxy” refers to O-alkyl groups, wherein alkyl is as defined hereinabove. The alkoxy group is bonded to the core compound through the oxygen bridge. The alkoxy group may be straight-chained or branched; although the straight-chain is preferred. Examples include methoxy, ethyloxy, propoxy, butyloxy, t- butyloxy, i-propoxy, and the like. Preferred alkoxy groups contain 1 -4 carbon atoms, especially preferred alkoxy groups contain 1-3 carbon atoms. The most preferred alkoxy group is methoxy.

[0058] As used herein, the term “halogen” means the non-metal elements of Group 17 of the periodic table, namely bromine, chlorine, fluorine, iodine and astatine. The terms “alkyl”, “cycloalkyl”, “heterocycloalkyl”, “cycloalkylalkyl”, “aryl”, “acyl”, “aromatic polycycle”, “heteroaryl”, “arylalkyl”, “heteroarylalkyl”, “amino acyl”, “non-aromatic polycycle”, “mixed aryl and non-aryl polycycle”, “polyheteroaryl”, “non-aromatic polyheterocyclic”, “mixed aryl and non-aryl polyheterocycles”, “amino”, and “sulphonyl” are defined in US6,552,065, Column 4, line 52 to Column 7, line 39. “Halogen” means the non-metal elements of Group 17 of the periodic table, namely 20 bromine, chlorine, fluorine, iodine and astatine.

[0059] As used herein, the term “PEG” refers to polyethylene glycol which is a polyether compound comprising an ethylene moiety derived from petroleum with many applications from industrial manufacturing to medicine. PEG has a structure in which n is usually 2, 3, 4, 5 or 6.

[0060] As used herein, the term “coumarin” refers to a group of compounds with a chemical scaffold comprising the chemical formula CgHxO2and comprising a fused benzene and a-pyrone rings. Coumarin and its derivatives are frequently found in the seeds, roots, and leaves of many plant species. The coumarin scaffold has been investigated for its pharmacological effects including anticancer, anticoagulant, antimicrobial, antiinflammatory, neuroprotective, antidiabetic, anticonvulsant, and antiproliferative. Together with their low toxicity and multifaceted biological activities have ensured their prominent role as lead compounds in drug research and development.

[0061] As used herein, the term “Carboxylate” refers to the conjugate base of a carboxylic acid. Carboxylates are sometimes referred to as carboxylic acid salts because a carboxylate is a salt formed by the direct deprotonation of the carboxylic acid with a base.

[0062] As used herein, the term “hydroxamates” refers to a class of organic compounds containing the functional group -C(O)-N(R)O-. They are the conjugate base of hydroxamic acids. Deprotonation occurs at OH of the hydroxamic acid which facilitates metal chelating through the vacant oxygen atoms on the ligand.

[0063] As used herein, the term “Counterion” refers to an ion having an opposite charge to that of the molecule it is associated with. Metal complexes usually carry a positive charge on the metal center resulting in the requirement of charge to be balanced. “Compositions”: The invention also relates to a composition comprising the compound of the invention. The compound may be modified or provided as a conjugate. The composition may be a food ingredient powder, food beverage, dietary supplement, pharmaceutical composition, topical composition, antiseptic composition, antibacterial composition, surface cleaning product. The composition may be in the form of a liquid, gel, cream, ointment, powder, granule. The composition may comprise other components for example selected from an anti-bacterial agent, detergent, fragrance, colouring agent, emulsifiers and stabilisers.

[0064] The composition may be a cosmetic or pharmaceutical composition. The compounds of the invention are used in the cosmetic (i.e. topical cosmetic) or pharmaceutical composition of this invention at cosmetically or pharmaceutically effective concentrations to achieve the desired effect; in a preferred form with regards to the total weight of the composition, between 0.00000001 % (in weight) and 20% (in weight); preferably between 0.000001 % (in weight) and 15% (in weight), more preferably between 0.0001 % (in weight) and 10% (in weight) and even more preferably between 0.0001 % (in weight) and 5% (in weight). Ideally, the compounds of the present invention are preferably used from about 0.00001 % w / w to about 0.5% w / w [0.1 to 5000 ppm], and more preferably from 0.00005 w / w to about 0.05 w / w [0.5 to 500 ppm], and most preferably from about 0.0001 w / w to about 0.01 w / w of the composition [1 to 100 ppm]. Ideally, the compounds of the present invention are preferably used from about 0.0001 % w / w to about 0.004% w / w of the composition.

[0065] “Topical compositions”: The invention also relates to a topical composition comprising a compound or composition of the invention. It will be appreciated that the topical composition may comprise a compound of the invention in combination with other agents. The topical composition of the invention may be presented in a formulation selected from the group comprising creams, multiple emulsions, anhydrous compositions, aqueous dispersions, oils, milks, balsams, foams, lotions, gels, cream gels, hydro-alcoholic solutions, hydro-glycolic solutions, cosmetic, personal care product, household cleaning product, hydrogels, liniments, sera, soaps, dusting powder, paste, semi solid formulations, liniments, serums, shampoo, conditioner, ointments, any rinse off formulation, talc, mousses, powders, sprays, aerosols, solutions, suspensions, emulsions, syrups, elixirs, polysaccharide films, patches, gel patches, bandages, an adhesive system, water-in-oil emulsions, oil-in-water emulsions, and silicone emulsions.

[0066] “Pharmaceutical compositions”: A further aspect of the invention relates to a pharmaceutical composition comprising a compound of the invention or a composition of compounds of the invention, admixed with one or more pharmaceutically acceptable diluents, excipients or carriers. Even though the compounds and compositions of the present invention can be administered alone, they will generally be administered in admixture with a pharmaceutical carrier, excipient or diluent, particularly for human therapy. The pharmaceutical compositions may be for human or animal usage in human and veterinary medicine. Examples of such suitable excipients for the various different forms of pharmaceutical compositions described herein may be found in the “Handbook of Pharmaceutical Excipients, 2nd Edition, (1994), Edited by A Wade and PJ Weller. In particular, formulations for topical delivery are described in Topical drug delivery formulations edited by David Osborne and Antonio Aman, Taylor & Francis, the complete contents of which are incorporated herein by reference. Acceptable carriers or diluents for therapeutic use are well known in the pharmaceutical art, and are described, for example, in Remington's Pharmaceutical Sciences, Mack Publishing Co. (A. R. Gennaro edit. 1985). Examples of suitable carriers include lactose, starch, glucose, methyl cellulose, magnesium stearate, mannitol, sorbitol and the like. Examples of suitable diluents include ethanol, glycerol and water. The choice of pharmaceutical carrier, excipient or diluent can be selected with regard to the intended route of administration and standard pharmaceutical practice. The pharmaceutical compositions may comprise as, or in addition to, the carrier, excipient or diluent any suitable binder(s), lubricant(s), suspending agent(s), coating agent(s), solubilising agent(s). Examples of suitable binders include starch, gelatin, natural sugars such as glucose, anhydrous lactose, free-flow lactose, beta-lactose, corn sweeteners, natural and synthetic gums, such as acacia, tragacanth or sodium alginate, carboxymethyl cellulose and polyethylene glycol. Examples of suitable lubricants include sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. Preservatives, stabilizers, dyes and even flavouring agents may be provided in the pharmaceutical composition. Examples of preservatives include sodium benzoate, sorbic acid and esters of p hydroxybenzoic acid. Antioxidants and suspending agents may be also used. The compound or composition of the invention may be adapted for topical, oral, rectal, parenteral, intramuscular, intraperitoneal, intra-arterial, intrabronchial, subcutaneous, intradermal, intravenous, nasal, vaginal, buccal or sublingual routes of administration. For oral administration, particular use is made of compressed tablets, pills, tablets, gellules, drops, and capsules. Preferably, these compositions contain from 1 to 250 mg and more preferably from 10-100 mg of active ingredient per dose. Other forms of administration comprise solutions or emulsions which may be injected intravenously, intra-arterial, subcutaneously, intradermally, intraperitoneally or intramuscularly, and which are prepared from sterile or sterilisable solutions. The pharmaceutical compositions of the present invention may also be in form of suppositories, vaginal rings, pessaries, suspensions, emulsions, lotions, ointments, creams, gels, sprays, solutions or dusting powders. The composition of the invention may be formulated for topical delivery. Topical delivery generally means delivery to the skin, but can also mean delivery to a body lumen lined with epithelial cells, for example the lungs or airways, the gastrointestinal tract, the buccal cavity. In particular, formulations for topical delivery are described in Topical drug delivery formulations edited by David Osborne and Antonio Aman, Taylor & Francis, the complete contents of which are incorporated herein by reference. Compositions or formulations for delivery to the airways are described in O’Riordan et al (Respir Care, 2002, Nov. 47), EP2050437, W02005023290, US2010098660, and US20070053845. Composition and formulations for delivering active agents to the iluem, especially the proximal iluem, include microparticles and microencapsulates where the active agent is encapsulated within a protecting matrix formed of polymer or dairy protein that is acid resistant but prone to dissolution in the more alkaline environment of the ileum. Examples of such delivery systems are described in EP1072600.2 and EP13171757.1 . An alternative means of transdermal administration is by use of a skin patch. For example, the active ingredient can be incorporated into a cream consisting of an aqueous emulsion of polyethylene glycols or liquid paraffin. The active ingredient can also be incorporated, at a concentration of between 1 and 10% by weight, into an ointment consisting of a white wax or white soft paraffin base together with such stabilisers and preservatives as may be required.

[0067] Injectable forms may contain between 10-1000 mg, preferably between 10-250 mg, of active ingredient per dose. Compositions may be formulated in unit dosage form, i.e., in the form of discrete portions containing a unit dose, or a multiple or sub-unit of a unit dose.

[0068] A person of ordinary skill in the art can easily determine an appropriate dose of one of the instant compositions to administer to a subject without undue experimentation. Typically, a physician will determine the actual dosage which will be most suitable for an individual patient and it will depend on a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the individual undergoing therapy. The dosages disclosed herein are exemplary of the average case. There can of course be individual instances where higher or lower dosage ranges are merited, and such are within the scope of this invention. Depending upon the need, the agent may be administered at a dose of from 0.01 to 30 mg / kg body weight, such as from 0.1 to 10 mg / kg, more preferably from 0.1 to 1 mg / kg body weight. In an exemplary embodiment, one or more doses of 10 to 300 mg / day or more preferably, 10 to 150 mg / day, will be administered to the patient for the treatment of an inflammatory disorder.

[0069] In a particularly preferred embodiment, the methods and uses of the invention involve administration of a compound or composition of the invention in combination with one or more other active agents, for example, existing antibacterial drugs or pharmacological enhancers available on the market. In such cases, the compounds of the invention may be administered consecutively, simultaneously or sequentially with the one or more other active agents.

[0070] Exemplification

[0071] The invention will now be described with reference to specific Examples. These are merely exemplary and for illustrative purposes only: they are not intended to be limiting in any way to the scope of the monopoly claimed or to the invention described. These examples constitute the best mode currently contemplated for practicing the invention.

[0072] c eme

[0073] Experimental

[0074] Compound 2

[0075] To a suspension of anhydrous potassium carbonate (1 .48 g, 10.70 mmol) in anhydrous acetonitrile was added 2,4-dihydroxyacetophenone (1.52 g, 10.00 mmol). The resulting salmon coloured solution was stirred for 20 min at reflux temperature. After this time, benzyl bromide (1.44 g, 1.17 mL, 9.87 mmol) was added in one portion. The resulting reaction mixture was stirred at reflux temperature under nitrogen. Monitoring the reaction progress using TLC, the reaction was complete after 4 h. Upon cooling excess potassium carbonate was removed via vacuum filtration, the filtrate was collected, and acetonitrile removed under reduced pressure to obtain a yellow coloured oil. This was triturated with hexane to achieve a white coloured crystalline powder. Molecular formula: C15H14O3; Yield: 2.10 g (88%); M.P. (°C): 102.7-104.1 Rf: 0.40 (90:10 hexane:ethyl acetate);1H NMR (500 MHz)(DMSO-d6)(ppm): 7.83 (d, 1 H, J = 8.9 Hz), 7.45 (m, 5H, H), 6.58 (dd, 1 H, J = 2.5, 8.9 Hz), 6.55 (d, 1 H, J = 2.5 Hz), 5.18 (s, 2H), 2.56 (s, 3H);13C NMR (DMSO-d6)(ppm): 203.2, 164.7, 163.9, 136.3, 133.3, 128.5 , 128.0, 127.8, 113.9, 107.8, 101.7, 69.6, 26.6; I.R. (KBr)(crrr1): 3084, 3031 , 3002, 2940, 2879, 1624, 1570, 1495, 1388, 1365, 1325, 1248, 1184, 1134, 1066, 1006, 956, 913, 840, 815, 763, 741 , 714, 697, 623, 561 , 483.

[0076] Compound 3

[0077] To a suspension of sodium hydride (60% mineral oil)(1 .28 g, 32 mmol) in anhydrous toluene (10 mL) was added a solution of 2-hydroxy-4-benzyloxyacetophenone (0.969 g, 4.00 mmol) in anhydrous toluene (5 mL). Upon addition the reaction suspension changed colour to a pale green and fizzing was observed. When the fizzing subsided, the reaction suspension was heated to 120 °C and stirred under nitrogen for 20 min. After this time, diethyl carbonate (1.936 mL, 16.00 mmol) was added in one portion and the reaction temperature increased to 140 °C. The reaction mixture was stirred for 24 h. After this time, the reaction mixture was cooled to room temperature and cold deionised water (30 mL) was added. The aqueous solution was extracted with ethyl acetate (2 x 30 mL) and the aqueous phase collected. The aqueous solution was acidified to pH 1 with 2 M hydrochloric acid to precipitate the product. The product was collected via vacuum filtration and washed with deionised water (2 x 10 mL). The white solid was collected and dried in a vacuum oven at 50 °C.

[0078] Molecular formula: CI6HI2O4; Yield: (1.06 g, 98%); M.P. (°C) 278.1 -280; Rf: 0.18 (95:5, dichloromethane:methanol);1H NMR (500 MHz)(DMSO-d6)(ppm): 12.36 (s, 1 H), 7.72 (d, 1 H, J = 8.8 Hz,), 7.48-7.33 (m, 5H), 7.04 (d, 1 H, J = 2.4 Hz), 6.99 (dd, 1 H, J = 2.4, 8.8 Hz), 5.44 (s, 1 H), 5.21 (s, 2H);13C NMR (DMSO-d6)(ppm): 166.4, 162.7, 162.4, 155.8, 136.7, 129.0, 128.6, 128.4, 124.8, 112.9, 109.5, 101.9, 89.0, 70.3; I.R. (KBr, cm’1): 3035, 2737, 2586, 1690, 1653, 1629, 1616, 1453, 1382, 1359, 1307, 1273, 1246, 1226, 1167, 1098, 1009, 988, 907, 845, 825, 695, 594, 542, 458.

[0079] General method for PEGylation of hydroxycoumarins To a solution of anhydrous dimethylformamide (4 mL) containing anhydrous potassium carbonate (5 equiv.) was added the hydroxycoumarin (1.1 equiv.). A yellow-coloured suspension was produced immediately upon its addition. After stirring for 20 min at room temperature a solution of anhydrous dimethylformamide containing (mPEG)-OTs (1 equiv.) was added in one portion and the suspension stirred for a further 5 min. The pale yellow coloured suspension was then stirred under microwave irradiation at 140 °C for 25 min. Upon reaction completion, the suspension was added to water (20 mL) to dissolve the excess potassium carbonate. This aqueous solution was then extracted with ethyl acetate (3 x 15 mL). The ethyl acetate layers were collected and then washed several times with brine solution to remove dimethylformamide. The ethyl acetate layer was collected, dried over sodium sulfate and the filtrate collected. The ethyl acetate was removed under reduced pressure to obtain a red coloured oil.

[0080] Compound 4 - (mPEGh

[0081] Using the general method for PEGylation of hydroxycoumarins, this compound was synthesised using the following reagents: 4-hydroxy-7-benzyloxycoumarin (0.402 g, 1.50 mmol), 2-(2-m ethoxyethoxy) ethyl 4-methylbenzene sulfonate (0.242 g, 1.00 mmol) and anhydrous potassium carbonate (0.691 g, 5.00 mmol). Reaction completion was indicated by TLC using an 80:20, ethyl acetate: hexane mobile phase. Following extraction with ethyl acetate and water, the organic layers were collected, dried over sodium sulfate and the filtrate collected. The solvent was removed under reduced pressure to obtain a red coloured oily solid. This was dissolved in ethyl acetate (5 mL) and the product precipitated from solution using ice-cold PET ether (30 mL). The product was recovered via vacuum filtration. The beige coloured solid was washed with ice-cold petroleum ether, collected and dried under vacuum at 35 °C for several hours.

[0082] Molecular formula: C21H22O6; Yield: 0.224 g (60%); M.P. (°C): 70.1-73.8; Rf: 0.42 (80:20, hexane: ethyl acetate);1H NMR (DMSO-d6)(ppm): 7.70 (d, 1 H, J = 8.8 Hz), 7.50-7.33 (m, 5H), 7.08 (d, 1 H, J = 2.4 Hz), 7.04 (dd, 1 H, J = 8.8, 2.4 Hz), 5.77 (s, 1 H), 5.22 (s, 2H), 4.31 (m, 2H), 3.83 (m, 2H), 3.63 (m, 2H), 3.47 (m, 2H), 3.24 (s, 3H);13C NMR (DMSO-d6)(ppm): 165.7, 162.5, 162.4, 155.0, 136.7, 129.0, 128.6, 128.4, 124.5, 113.3, 108.9, 101.9, 88.7, 71.7, 70.4, 70.3, 69.5, 68.6, 58.6; I.R. (KBr, cm’1): 3090, 306, 3030, 2889, 2821 , 1721 , 1616, 1443, 1432, 1405, 1393, 1382, 1370, 1350, 1285, 1245, 1160, 1141 , 1131 , 1115, 1106, 1083, 1044, 1029, 999, 984, 950, 907, 854, 822, 807, 731 , 694; CHN (%): theory: C = 68.10, H = 5.59 ; found: C = 64.77, H = 5.53; M / Z [M+H]+: theory: 371.1489, found: 371.1506.

[0083] Compound 4 - (mPEGh

[0084] Using the same method as described for compound 4 - (mPEGk, this compound was synthesised using the following reagents: 4-hydroxy-7-benzyloxycoumarin (0.4101 g, 1.53 mmol), mPEG4-OTs (0.369 g, 1.02 mmol), anhydrous potassium carbonate (0.705 g, 5.10 mmol). A burgundy-coloured oil was obtained.

[0085] Molecular formula: C25H30O8; Yield: 0.326 g (81 %); Rf: 0.32 (95:5, dichloromethane:methanol);1H NMR (DMSO-d6)(ppm): 7.70 (d, 1 H, J = 8.8 Hz), 7.49- 7.33 (m, 5H), 7.07 (d, 1 H, J = 2.4 Hz), 7.03 (dd, 1 H, J = 8.8, 2.5 Hz), 5.76 (s, 1 H), 5.21 (s, 2H), 4.34-4.29 (m, 2H), 3.86-3.83 (m, 2H), 3.65-3.61 (m, 2H), 3.57-3.46 (m, 9H), 3.41 -3.38 (m, 2H), 3.21 (s, 3H);13C NMR (DMSO-d6)(ppm): 165.3, 162.0, 161.9, 154.6, 136.2, 128.5, 128.1 , 127.9, 124.0, 112.8, 108.5, 101.5, 88.2, 71.3, 70.0, 69.9, 69.8, 69.8, 69.8, 69.6, 69.0, 68.1 , 58.0; I.R. (NaCI plate): 3531 , 3090, 3033, 2877, 1716, 1617, 1560, 1512, 1454, 1427, 1401 , 1388, 1356, 1281 , 1241 , 1152, 1105, 1025, 948, 903, 844, 810, 739, 699, 654, 584; M / Z [M+H]+: theory: 459.1990, found: 459.2013.

[0086] Compound 5 - (mPEGh

[0087] Compound 4 - (mPEGk (0.555 g, 1.50 mmol) was solubilised in a 50:50 mixture of DMF: dioxane and was then catalytically debenzylated over Pd / C (10%) using hydrogen gas. Following reaction completion as indicated by TLC, the catalyst was removed via vacuum filtration over a pad of Celite The filtrate was collected, and water added. This mixture was then extracted with ethyl acetate (3 x 15 mL). The ethyl acetate layer was collected, dried over sodium sulfate and the solvent removed under reduced pressure to obtain a light-red coloured solid. This was dissolved in ethyl acetate and ice-cold petroleum ether added to precipitate the product. The precipitate was collected via vacuum filtration and washed first with water (10 mL) and then with ice-cold petroleum ether (10 mL). The peach-coloured powder was collected and dried in a vacuum oven at 35 °C for several hours.

[0088] Molecular formula: CI4HI6O6; Yield: 0.288 g (69%); M.P. (°C): 152.2-155.6 Rf: 0.32 (80:20, hexane: ethyl acetate);1H NMR (DMSO-d6)(ppm): 10.59 (s, 1 H), 7.61 (d, 1 H, J = 8.8 Hz), 6.80 (dd, 1 H, J = 8.8, 2.4 Hz), 6.70 (d, 1 H, J = 2.4 Hz), 5.69 (s, 1 H), 4.32- 4.27 (m, 2H), 3.84-3.80 (m, 2H), 3.65-3.59 (m, 2H), 3.48-3.44 (m, 2H), 3.24 (s, 3H);13C NMR (DMSO-d6)(ppm): 165.4, 162.1 , 161.6, 154.5, 124.1 , 112.7, 106.9, 101.9, 87.3, 71.2, 69.7, 68.8, 68.1 , 57.9; I.R. (KBr)(crrr1): 3021 , 3080, 2092, 2876, 2813, 1702, 1598, 1568, 1414, 1390, 1539, 1287, 1246, 1144, 1105, 1031 , 1011 , 1003, 922, 867, 837, 807; CHN (%): theory: C = 60.00, H = 5.75; found: C = 60.69, H = 5.62, M / Z [M+H]+: theory: 281.1010, found: 281.1018.

[0089] Compound 5 - (mPEGh

[0090] Compound 4 - (mPEGk OBnC (0.373 g, 0.812 mmol) was solubilised in anhydrous methanol. This was then catalytically debenzylated over Pd / C (10%) using hydrogen gas. Upon reaction completion as indicated by TLC, the catalyst was removed via vacuum filtration over a pad of Celite. The filtrate was collected and methanol removed under reduced pressure to obtain an off-white coloured oily-solid. This was dissolved in ethyl acetate and petroleum ether added to precipitate the product. The product was collected via vacuum filtration. A white coloured powder was isolated and dried in a vacuum oven at 25 °C for several hours.

[0091] Molecular formula: Ci8H24O8; Yield: 0.175g (59%); M.P. (°C): 87.8-89.9; Rf: 0.23 (95:5, dichloromethane:methanol);1H NMR (DMSO-d6)(ppm): 10.59 (s, 1 H), 7.61 (d, 1 H, J = 8.6 Hz), 6.79 (dd, 1 H, J = 8.7, 2.3 Hz), 6.69 (d, 1 H, J = 2.3 Hz), 5.68 (s, 1 H), 4.31 -4.28 (m, 2H), 3.85-3.82 (m, 2H), 3.64-3.61 (m, 2H), 3.56-3.47 (m, 8H), 3.41-3.38 (m, 2H), 3.22 (s, 3H);13C NMR (DMSO-d6)(ppm): 165.5, 162.1 , 161.8, 154.7, 124.2, 112.8, 107.0, 102.0, 87.3, 71.2, 70.0, 69.8, 69.77, 69.74, 69.5, 68.8, 68.2, 58.0; I.R. (KBr)(cm-1): 3199, 3080, 2891 , 1705, 1597, 1570, 1416, 1377, 1359, 1288, 1247, 1156, 1111 , 1029, 1003, 955, 922, 867, 839; CHN (%): theory: C = 58.69, H = 6.57; found: C = 58.36, H = 6.33; M / Z [M+H]+: theory: 369.1554, found: 369.1556. General method for alkylation with ethyl bromoacetate

[0092] To a suspension of anhydrous potassium carbonate (1.0 mmol) in anhydrous acetonitrile (20 mL) was added the appropriately substituted hydroxycoumarin (1.0 mmol). The reaction mixture was heated to reflux and stirred for 20 min. Then, ethyl bromoacetate (1 .0 mmol) was added in a single portion and the reaction stirred under nitrogen for 4-6 h. Upon completion of the reaction as indicated by TLC using an 80:20 hexane: ethyl acetate mobile phase, the reaction mixture was cooled. Upon cooling, excess potassium carbonate was removed via vacuum filtration. The filtrate was collected, and acetonitrile removed under reduced pressure to obtain a pale-yellow solid. The crude product was triturated with hexane to obtain a white coloured crystalline solid which was then collected and dried in a vacuum oven at 50 °C for several hours.

[0093] Compound 6 - (mPEGh

[0094] Using the general method for alkylation with ethyl bromoacetate, this compound was synthesised using the following reagents: Compound 5 - (mPEGk (0.266 , 0.95 mmol), anhydrous potassium carbonate (0.131 g, 0.95 mmol), ethyl bromoacetate (0.159 g, 0.105 mL, 0.95 mmol). Following the work-up, a pale red coloured oil was obtained. This was dissolved in ethyl acetate (10 mL) and ice-cold petroleum ether (30 mL) added to precipitate the product. A pale pink amorphous solid was obtained. This was dried under vacuum at 35 °C for several hours.

[0095] Molecular formula: C18H22O8; Yield: 0.293 g (84%); M.P. (°C): Rf: 0.38 (80:20, ethyl acetate: hexane);1H NMR (DMSO-d6)(ppm): 7.70 (d, 1 H, J = 9.5 Hz), 7.02-6.97 (m, 2H), 5.79 (s, 1 H), 4.93 (s, 2H), 4.33-4.30 (m, 2H), 4.18 (q, 2H, J = 7.1 Hz), 3.85-3.81 (m, 2H), 3.64-3.61 (m, 2H), 3.48-3.45 (m, 2H), 3.24 (s, 3H) 1.22 (t, 3H, J = 7.2 Hz);13C NMR (DMSO-d6)(ppm): 168.0, 165.1 , 161.9, 161.0, 154.3, 123.9, 112.4, 108.7, 101.3, 88.3, 71.2, 69.7, 68.9, 68.0, 64.8, 60.7, 57.9, 13.9; I.R. (KBr)(crrr1): 3079, 2970, 2936, 2876, 2821 , 1753, 1718, 1617, 1560, 1445, 1432, 1383, 1370, 1350, 1292, 1246, 1225, 1203, 1156, 1129, 1117, 1070, 1044, 1024, 984, 949, 908, 868, 856, 805, 747; CHN (%): theory: C = 59.01 , H = 6.05; found: C = 56.24, H = 6.29 (C18H22O8. I H2O) ; M / z [M+H]+: theory: 367.1387, found: 367.1384. Compound 6 - (mPEGh

[0096] Using the general method for alkylation with ethyl bromoacetate, this compound was synthesised using the following reagents: Compound 5 - (mPEG (0.212 g, 0.58 mmol), anhydrous potassium carbonate (0.079 g, 0.58 mmol), ethyl bromoacetate (0.096 g, 0.0639 mL, 0.58 mmol). A pale yellow coloured oil was obtained.

[0097] Molecular formula: C22H30O10 Yield: 0.242 g (92%); Rf: 0.25 (95:5, dichloromethane:methanol);1H NMR (DMSO-d8)(ppm): 7.70 (d, 1 H J = x Hz), 7.01- 6.95 (m, 2H), 5.78 (s, 1 H), 4.93 (s, 2H), 4.35-4.30 (m, 2H), 4.18 (q, 2H, J = 7.1 Hz), 3.88-3.82 (m, 2H), 3.6-3.61 (m, 2H), 3.57-3.46 (m, 9H), 3.40 (m, 2H), 3.22 (s, 3H), 1.22 (t, 3H, J =7.1 Hz);13C NMR (DMSO-d6)(ppm): 168.1 , 165.2, 161.9, 161.2, 154.4, 124.0, 112.5, 108.9, 101.4, 88.4, 71.3, 70.0, 69.8, 69.8, 69.7, 69.6, 69.0, 68.1 , 64.9,

[0098] 60.8, 58.0, 14.0; I.R (NaCI plate): 3091 , 2876, 1755, 1719, 1617, 1562, 1512, 1451 , 1401 , 1288, 1243, 1219, 1199, 1154, 1107, 1071 , 1030, 983, 904, 852, 811 ; M / z [M+H]+: theory: 455.1912, found: 455.1899.

[0099] Compound 7 - (mPEGh

[0100] Compound 6 - (mPEGk (0.550 g, 1.63 mmol) was stirred in a 10% HCI (40:60, acetone:water) (20 mL) solution at 70 °C for 24 h. Upon cooling to room temperature, the reaction flask was cooled in an ice-bath to encourage the precipitation of the product from solution. The precipitate was collected via vacuum filtration and washed with ice-cold water (2 x 10 mL) then dried in a vacuum oven at 35 °C for several hours to obtain an off-white coloured needle-like solid.

[0101] Molecular formula: CI6HI8O8: Yield: 0.351 g, (53%); M.P. (°C): 134.2-137.8;1H NMR (DMSO-d6) (ppm): 13.16 (s, 1 H), 7.69 (d, 1 H, J = 9.0 Hz), 6.99-6.96 (m,2H), 5.78 (s, 1 H), 4.83 (s, 2H), 4.33-4.31 (m, 2H), 3.85-3.83 (m, 2H), 3.64-3.62 (m, 2H),3.48- 3.46 (m, 2H), 3.24 (s, 3H);13C NMR (DMSO-d6)(ppm): 168.9, 164.6, 161.4, 160.7,

[0102] 153.8, 123.4, 111.8, 108.1 , 100.7, 87.7, 70.7, 69.2, 68.4, 67.6, 64.2, 57.5; I.R. (KBr)(cm-1): 3369, 3084, 2915, 2873, 2767, 2716, 2561 , 1765, 1696, 1616, 1564, 1451 , 1426, 1416, 1407, 1394, 1285, 1245, 1224, 1171 , 1107, 1092, 1069, 1006, 932, 883, 845, 816, 748, 728, 653, 619; CHN (%): theory: C = 56.33, H = 6.15; found: C = 53.01 , H = 5.65 (if Ci6Hi8O8.H2O; C = 53.93, H = 5.66).

[0103] Compound 7 - (mPEGh

[0104] Using the same method as described for compound 7 - (mPEGk, Compound 6 - (mPEG)4 (0.568 g, 1.25 mmol) and 10% HCI (40:60, acetone:water)(20 mL) solution were reacted. Following extraction of acidic aqueous phase with ethyl acetate, the ethyl acetate layers were collected, dried and the solvent removed under reduced pressure. The resulting white solid was triturated with hexane, recovered via vacuum filtration and dried in a vacuum oven at 25 °C for several hours.

[0105] Molecular formula: C20H26O10: Yield: 0.367 g, (69%); M.P. (°C): 98.5-102.0;1H NMR (DMSO-d6) (ppm): 13.13 (s, 1 H), 7.70 (d, 1 H, J = 9.3 Hz), 6.99-6.95 (m,2H), 5.78 (s, 1 H), 4.83 (s, 2H), 4.35-4.30 (m, 2H), 3.87-3.82 (m, 2H), 3.57-3.47 (m, 8H), 3.42-3.38 (m, 2H), 3.22 (s, 3H);13C NMR (DMSO-d6)(ppm): 170.0, 165.7, 162.4, 161.8, 154.9, 124.5, 112.9, 109.2, 101.8, 88.8, 71.7, 70.5, 70.29, 70.27, 70.24, 70.0, 69.5, 68.6, 65.3, 58.5; I.R. (KBr)(crrr1): 3801 , 2890, 1744, 1689, 1619, 1560, 1448, 1428,1298, 1199, 1162, 1099, 1071 , 1026, 992, 954, 879, 842, 662, 560, 495, 474; CHN (%): theory: C = 56.33, H = 6.15; found: C = 57.37 , H = 6.14.

[0106] General method for synthesis of coumarin carboxylate silver (I) complexes

[0107] The silver(l) complexes were synthesised by dissolving the appropriate ligand (1.00 mmol) in deionised water (10 mL) which contained sodium hydrogen carbonate (1.00 mmol). Once fully dissolved, a solution of silver(l) nitrate (1.00 mmol) in deionised water (10 mL) was added and upon addition a white coloured precipitate formed immediately. The resulting suspension was stirred at room temperature in the absence of light for 1 h. After this time the product was collect via vacuum filtration and washed with cold deionised water (2 x 10 mL), collected and dried in a vacuum oven at 50 °C in the absence of light for several days.

[0108] Compound 8 - (mPEGh Aq(l) complex This compound was synthesised using the general method for silver (I) complex formation, using the following reagents: Compound 7 - (mPEGk (0.200 g, 0.592 mmol), sodium hydrogen carbonate (0.0496 g, 0.592 mmol) and silver nitrate (0.1004 g, 0.592 mmol). Following a 3 h reaction time, the precipitate was isolated via vacuum filtration, washed with water (2 x 10 mL) collected and dried under vacuum at 35 °C for several hours.

[0109] Molecular formula: Ci6Hi7O8Ag; Yield: 0.0741 g (28%); M.P. (°C): 241.9-244.7;1H NMR (DMSO-d6) (ppm): 7.65 (d, 1 H, J = 8.8 Hz), 6.89 (dd, 1 HJ = 8.9, 2.4 Hz), 6.76 (d, 1 H J = 2.5 Hz), 5.73 (s, 1 H), 4.49 (s, 2H), 4.33 - 4.30 (m, 2H), 3.84 - 3.82 (m, 2H),

[0110] 3.64 - 3.62 (m, 2H), 3.48 - 3.46 (m, 2H), 3.24 (s, 3H);13C NMR (DMSO-d6)(ppm): 170.5, 165.4, 162.6, 162.1 , 154.4, 123.6, 112.7, 107.8, 101.1 , 87.8, 71.3, 69.9, 68.9, 68.2, 67.7, 58.1 ; I.R. (KBr, cm’1): 3067, 2929, 2556, 1695, 1630, 1405, 1351 , 1299, 1271 , 1251 , 1161 , 1124, 1111 , 1045, 936, 882, 866, 813, 747, 718, 684, 540; CHN (%): theory: (Ci6Hi7O8Ag.H2O): C = 41.49, H = 4.13; found: C = 41.99, H = 3.75; M / Z [M+H]+: theory: 445.0053, found: 445.0050; Solubility: DMSO, water.

[0111] Compound 8 - (mPEGh Aq(l) complex

[0112] To a suspension of silver oxide (13.5 mg, 0.058 mmol) in anhydrous acetonitrile (3.5 mL) was added a yellow-coloured solution of Compound 7 - (mPEG (50 mg, 0.117 mmol) in anhydrous acetonitrile (3.5 mL). The resulting colourless suspension was stirred for 4 h at 40 °C under nitrogen. After this time, the suspension was cooled, and the silver oxide removed via filtration through a pad of Celite. The colourless filtrate was collected, and the solvent removed under reduced pressure in a water bath heated to 30 °C. A colourless oil was obtained.

[0113] Molecular formula: C2oH250ioAg; Yield: 25.6 mg (82%);1H NMR (DMSO-d6) (ppm):

[0114] 7.64 (d, 1 H, J = 8.8 Hz), 6.87 (dd, 1 HJ = 8.8, 2.4 Hz), 6.74 (d, 1 H J = 2.4 Hz), 5.72 (s, 1 H), 4.37 (s, 2H), 4.32 - 4.30 (m, 2H), 3.85 - 3.83 (m, 2H), 3.65 - 3.62 (m, 2H), 3.56 - 3.48 (m, 10H), 3.41-3.39 (m, 3H), 3.22 (s, 3H); I.R. (NaCI plate, cm’1): 3088; 2917, 2875, 1717, 1615, 1590, 1559, 1512, 1450, 1440, 1433, 1427, 1408, 1352, 1295, 1283, 1242, 1203, 1156, 1112, 1057, 981 , 905; M / Z [M+H]+: theory: 533.0499, found: 533.0571. Solubility: methanol, DMSO, water, acetonitrile, chloroform, dichloromethane. Compound 9 - (mPEGh Aq(l) (PPh3)2 complex

[0115] Compound 8 - (mPEGk Ag(l) complex (69.8 mg, 0.157 mmol) and triphenylphosphine (82.3 mg, 0.314 mmol) were stirred in ethanol (5 mL) at reflux temperature for 2 h in the absent of light. An off-white coloured crystalline powder was obtained following precipitation from ethyl acetate, which was filtered and dried at 50 °C for 48 h.

[0116] Molecular formula: C52H47O8P2Ag; Yield: 0.114 g (92%); M.P. (°C): 140.8-141.2;1H NMR (DMSO-d6)(ppm): 7.54 (d, 1 H, J = 8.8 Hz), 7.53-7.32 (m, 32H), 6.80 (dd, 1 H, J = 8.8, 2.4 Hz), 6.73 (d, 1 H, J = 2.4 Hz), 5.72, (s, 1 H), 4.42 (s, 2H), 4.31-4.30 (m, 2H), 3.86-3.80 (m, 2H); 3.68-3.58 (m, 2H), 3.51-3.41 (m, 2H), 3.23 (s, 3H);13C NMR

[0117] (DMSO-d6)(ppm): 170.4, 165.4, 162.6, 162.1 , 154.4, 133.5-133.4 (d), 132.1 -131 .9 (d), 130.5, 129.1 -129.0 (QC), 123.6, 112.5, 107.7, 101.2, 87.8, 71.3, 69.9, 68.9, 68.2, 67.8, 58.1 ; I.R. (KBr, cm’1): 3051 , 1722, 1608, 1581 , 1505, 1479, 1435, 1404, 1329, 1278, 1227, 1194, 1121 , 1095, 1041 , 843, 749, 693, 515, 503; CHN (%): theory: C = 64.40, H = 4.88; found: C = 64.85, H = 4.65.

[0118]

[0119] Experimental

[0120] Compound 11

[0121] To a suspension of silver oxide (2.55 g, 11 mmol) in diethyl ether (25 mL) was added methyl-2-glycolate (1.0 g, 0.85 mL, 11 mmol) in one portion. The suspension was stirred under nitrogen for 30 min in the absence of light. After this time, benzyl bromide (1 .88 g, 1 .30 mL, 11 mmol) was added in one portion and the resulting reaction mixture stirred for at 35 °C, until reaction completion was indicated by TLC (90: 10 hexane:ethyl acetate mobile phase). Upon cooling, the suspension was filtered through a pad of Celite to remove excess silver oxide. The filtrate was collected, and the volatiles removed under reduced pressure to obtain a colourless oil. The product (compound 10) was purified by flash chromatography using a 10% ethyl acetate: petroleum ether mobile phase.

[0122] Molecular formula: C10H12O3; Yield: 1.56 g (78%), Rf: 0.18 (90:10, hexane:ethyl acetate);1H NMR: (DMSO-d6) (ppm): 7.38-7.29 (m, 5H), 4.56 (s, 2H), 4.18 (s, 2H), 3.67 (s, 3H);13C NMR (DMSO-d6) (ppm): 170.5, 137.7, 128.2, 127.7, 127.6, 72.2, 66.9, 51.3; I.R. (NaCI plate, cm’1): 3089, 3065, 3007, 2954, 2867, 1755, 1497, 1455, 1438, 1394, 1282, 1211 , 1130, 1029, 1002, 651 , 889, 846, 742, 699, 607, 578.

[0123] Compound 10 (0.901 g, 5.00 mmol) and tert-butoxy bis(dimethylamino) methane (1 .09 g, 1 .29 mL, 6.25 mmol) were stirred under nitrogen for 24 h at 100 °C. Upon reaction completion as indicated by TLC (90:10 hexane:ethyl acetate mobile phase), the resulting dark red coloured oil was cooled and the t-butanol by-product removed under reduced pressure. The viscous red oil was suspended in glacial acetic acid (3 mL) and heated while stirring to 130 °C. To this, a solution of resorcinol (0.495 g, 4.50 mmol) in glacial acetic acid was added in one portion and the resulting bright red coloured solution stirred under nitrogen at 130 °C until reaction completion was again indicated by TLC (approximately 4 h). Upon cooling, the reaction mixture was extracted with ethyl acetate and water and the extraction repeated. The yellow-coloured ethyl acetate layers were collected, pooled together and dried over sodium sulfate. After filtration, the solvent removed under reduced pressure to yield a viscous solid which was recrystallised from ethyl acetate. The product was collected via vacuum filtration and washed with cold ethyl acetate (1 x 10 mL) and dried in a vacuum oven at 50 °C for several hours. A light brown powder was obtained.

[0124] Molecular formula: CI6HI2O4; Yield: 0.28 g (11 %); M.P. (°C): 233.7-234.8; Rf: 0.36 (60:40, hexane:ethyl acetate);1H NMR: (DMSO-d6) (ppm): 10.13 (s, 1 H), 7.48-7.35 (m, 7H), 6.77 (dd, 1 H, J = 2.3, 8.5 Hz), 6.71 (d, 1 H, J = 2.3 Hz), 5.08 (s, 2H);13C NMR (DMSO-d6): 158.4, 156.9, 150.6, 139.4, 135.8, 128.4, 128.1 , 127.9, 127.8, 116.4, 113.2, 111.3, 101.8, 70.2; I.R. (KBr, cm’1): 3265, 1685, 1627, 1603, 1508, 1453, 1369, 1281 , 1253, 1221 , 1163, 1145, 1113, 991 , 922, 877, 835, 762, 699, 595; CHN (%): Theory: C = 71 .64, H = 4.51 ; Found: C = 71 .73, H = 4.54.

[0125] Compound 12 Using the general method for alkylation with ethyl bromoacetate, this compound was synthesised using the following reagents: Compound 11 (0.269 g, 1.01 mmol), anhydrous potassium carbonate (0.139 g, 1.01 mmol) and ethyl bromoacetate (0.168 g, 0.112 mL, 1.01 mmol). A white coloured powder was isolated.

[0126] Molecular formula: C2OHI806; Yield: 0.274 g, (73%); M.P. (°C): 174.2-176.3; Rf: 0.53 (60:40, hexane:ethyl acetate);1H NMR (DMSO-d6) (ppm): 7.53-7.37 (m, 7H), 6.99 (d, 1 H, J = 2.5 Hz), 6.96 (dd, 1 H, J = 2.5, 8.6 Hz), 5.11 (s, 2H), 4.88 (s, 2H), 4.18 (q, 2H, J = 7.1 Hz), 1.22 (t, 3H, J = 7.1 Hz);13C NMR (DMSO_d6)(ppm): 168.2, 158.0, 156.7, 150.2, 140.8, 135.6, 128.4, 128.1 , 127.9, 127.7, 115.5, 113.2, 112.7, 101.2, 70.2, 64.8, 60.6, 13.9; I.R. (KBr, cm’1): 3077, 2990, 2907, 2881 , 1760, 1723, 1634, 1614, 1509, 1573, 1509, 1431 , 1401 , 1383, 1290, 1273, 1216, 1203, 1170, 1135, 1119, 1074, 1030, 991 , 970, 896, 831 , 814, 76, 755, 725, 700, 595; CHN (%): Theory: C = 67.79, H = 5.12; Found: C = 64.67, H = 4.78 (C2OHI806 + H2O).

[0127] Compound 14

[0128] Compound 13 (0.30 g, 0.85 mmol) was solubilised in anhydrous DMF:1 ,4-dioxane (1 :1 , 5 mL). The compound was catalytically debenzylated using 10% Pd / C on a hydrogenator at 3 atm. The reaction progress was monitored using TLC and was finished after 6 h. The reaction suspension was filtered through a pad of Celite to remove excess catalyst. The filtrate was collected, and water added. This mixture was then extracted with ethyl acetate (3 x 15 mL). The ethyl acetate layer was collected, dried over sodium sulfate and the solvent removed under reduced pressure to obtain a white powder. This was recrystallised from hot ethanol to obtain a colourless crystalline solid.

[0129] Molecular formula: C13H12O6; Yield: 0.141 g (63%); M.P. (°C): 157.2-157; Rf: 0.29 (60:40, hexane:ethyl acetate);1H NMR (DMSO-d6) (ppm): 10.04 (s, 1 H), 7.46 (d, 1 H, J = 8.7 Hz), 7.09 (s, 1 H), 6.96 (d, 1 H, J = 2.7 Hz), 6.92 (dd, 1 H, J = 2.5, 8.7 Hz), 4.86 (s, 2H), 4.17 (q, 2H, J = 7.1 Hz), 1.22 (t, 3H, J = 7.1 Hz);13C NMR (DMSO_d6)(ppm): 168.4, 158.5, 157.5, 150.2, 139.5, 127.2, 115.5, 114.2, 112.6, 101.3, 64.9, 60.7, 14.0; I.R. (KBr, cm’1): 3363, 2990, 2941 , 1748, 1694, 1643, 1610, 1509, 1411 , 1383, 1297, 1282, 1264, 1206, 1190, 1170, 1123, 1074, 1020, 903, 844, 772, 594, 463; CHN (%): Theory: C = 59.09, H = 4.58; Found: C = 61.33, H = 4.67. Compound 15 - (mPEGh

[0130] To a solution of anhydrous dimethylformamide (4 mL) containing anhydrous potassium carbonate (0.207 g, 1.50 mmol) was added compound 14 (0.0871 g, 0.33 mmol). A yellow-coloured suspension was produced immediately upon its addition. After stirring for 20 min at room temperature a solution of anhydrous dimethylformamide containing (mPEG)4-OTs (0.1087 g, 0.30 mmol) was added in one portion and the suspension stirred for a further s min. The pale-yellow coloured suspension was then stirred under microwave irradiation at 140 °C for 25 min. Upon reaction completion, the suspension was added to water (20 mL) to dissolve the excess potassium carbonate. This aqueous solution was then extracted with ethyl acetate (3 x 15 mL). The ethyl acetate layers were collected and then washed several times with brine solution to remove dimethylformamide. The ethyl acetate layer was collected, dried over sodium sulfate and the filtrate collected. The ethyl acetate was removed under reduced pressure to obtain a red coloured oil.

[0131] Molecular formula: C22H27O10; Yield: 76.6 mg, (57%); Rf: (95:5, dichloromethane:methanol);1H NMR (DMSO-d6) (ppm): 7.50 (d, 1 H, J = 8.5 Hz), 7.35 (s, 1 H), 6.98 (dd, 1 H, J = 8.5, 2.5 Hz), 4.87 (s, 2H), 4.10 (m, 2H), 3.77 (m, 2H), 3.62- 3.47 (m, 10H), 3.43-3.39 (m, 2H), 3.22 (s, 3H);13C NMR (DMSO_d6)(ppm): 168.8, 158.5, 157.2, 150.8, 141.6, 128.2, 115.5, 113.9, 113.3, 101.7, 71.7, 70.4, 70.3, 70.25, 70.22, 70.0, 68.9, 68.8, 65.4, 61.2, 58.5, 14.5; I.R. (NaCI plate, cm’1): 3066, 2927, 2876, 1735, 1627, 1617, 1550, 1507, 1446, 1384, 1327, 1278, 1247, 1208, 1167, 1137, 1116, 1029, 948, 852.

[0132] Compound 16

[0133] Compound 15 (0.115 g, 0.252 mmol) was stirred in a 10% HCI (40:60, acetone:water) (20 mL) solution at 50 °C for 24 h. Upon reaction completion as indicated by TLC, the acidic aqueous solution was cooled and extracted with ethyl acetate (3 x 15 mL). The ethyl acetate layers were pooled, dried over sodium sulfate and the filtrate collected. Ethyl acetate was removed under reduced pressure to give the product as an orangecoloured oil.

[0134] Molecular formula: C20H26O10: Yield: 0.106 g, (98%);1H NMR (DMSO-d6) (ppm): 13.08 (s, 1 H), 7.50 (d, 1 H, J = 9.0 Hz), 7.35 (s, 1 H), 6.97-6.91 (m, 2H), 4.77 (s, 2H), 4.14-4.08 (m, 2H), 3.80-3.75 (m, 2H), 3.62-3.47 (m, 10H), 3.44-3.39 (m, 2H), 3.22 (s, 3H);13C NMR (DMSO-d6) (ppm): 170.3, 158.7, 157.2, 150.8, 141.6, 128.2, 115.5, 113.7, 113.2, 101.7, 71.7, 70.4, 70.4, 70.3, 70.26, 70.2, 70.0, 68.9, 68.8, 65.3, 58.5; I.R. (NaCI plate, cm’1): 3074, 2917, 2883, 2852, 1732, 1619, 1508, 1433, 1383, 1350, 1328, 1273, 1246, 1201 , 1138, 1118, 831.

[0135] Ag(l) Complex 17

[0136] Compound 16 (0.1057 g, 0.257 mmol), sodium hydrogen carbonate (0.0208g, 0.247 mmol) and silver nitrate (0.0419 g, 0.247 mmol). Upon addition of the aqueous silver nitrate solution there was no precipitate formation. Following a 3 h reaction time a colour change from light orange to brown was observed. The water was removed under reduced pressure in a 40 °C water bath to obtain a light brown coloured solid. This was stirred in ethyl acetate and the solid collected via vacuum filtration. A dark red-brown crystalline powder was obtained and washed with cold ethyl acetate. This was collected and dried in a vacuum oven at 25 °C in the absence of light for several days.

[0137] Molecular formula: C2oH250ioAg; Yield: 70 mg (51 %); M.P. (°C): 182.0-186.0;1H NMR (500 MHz) (DMSO-d6) (ppm): 7.44 (d, 1 H, J = 8.8 Hz), 7.33 (s, 1 H), 6.85 (dd, 1 H, J = 8.7, 2.4 Hz), 6.76 (d, 1 H, J = 2.5 Hz), 4.38 (s, 2H), 4.11 (m, 2H), 3.77 (m, 2H), 3.62 - 3.48 (m, 11 H), 3.43 - 3.38 (m, 2H), 3.22 (s, 3H);13C NMR (DMSO-d6)(ppm): I.R. (KBr, cm’1): 3450, 2892, 1716, 1622, 1510,1383, 1271 , 1248, 1170, 1248, 1170, 1114, 947, 834, 668. Solubility: chloroform, dichloromethane, acetonitrile, DMSO, water. Stability of Compounds

[0138] The NMR spectra of the pegylated derivatives 8 and 9 in both DMSO and D2O (Figures 4 to 6), demonstrate both the solubility of the pegylated derivatives in aqueous systems and the photostability of the compounds over 96 h. The non-pegylated analogous compounds are neither soluble in D2O, nor stable in ambient light in DMSO.

[0139] Solubility Studies

[0140] Table 1. Solubility studies of coumarin derivatives

[0141] XX - insoluble at room temp, and when heated y - soluble at room temp.

[0142] X - soluble only when heated y* - partially soluble at room temp.

Claims

CLAIMS:1 . A compound of Formula (I):Formula (I) in which:R1to R6are each, independently, selected from H, Zi-PEG and Z2-A-Mn+;Zi and Z2 are each, independently, a linker; A is a carboxylate group or a hydroxamate group;Mn+is a metal ion selected from Zn2+, Sn2+, Cu2+, Cu+, Cd2+, Cr2+, Cr3+, Pt2+, Pt4+, Ni2+Pb2+, Pd, Ru2+, Rd, Au+, Au3+Ag+, Mn2+, Hg2+, Co+, Co2+, Co3+Fe2+, or Fe3+in which the metal ion is coordinated to one of more ligands to complete its coordination sphere;P+ designates the charge on the complex ion which may be positive, negative, or absent; andB is a counterion; in which one of R1and R2is one of Zi-PEG and Z2-A-Mn+and one of R3R4, R5, or R6is the other of Zi-PEG and Z2-A-Mn+.

2. A compound of Claim 1 , in which one of R1and R2is Zi-PEG and one of R3R4, R5, or R6is Z2-A-M+.

3. A compound of Claim 1 or 2, in which Zi and Z2 are each independently selected from aryl, alkyl, 0, S, NH, CH2, alkyl, lower alkyl, alkoxy, lower alkoxy, O-alkyl, CH2O, CH2NH, CO, and COO.

4. A compound of any preceding Claim, in which M+is selected from the group Zn2+, Sn2+, Cu2+, Cu1 +, Cd2+, Cr2+, Cr3+, Pt2+, Pt4+, Ni2+Pb2+, Pd, Ru2+, Rd, Au+, Au3+Ag+, Mn2+, Hg2+, Co1 +, Co2+, Co3+Fe2+, or Fe3+.

5. A compound of any preceding Claim, in which Z2-A-M+is -0-CH2-C(0)-0-M+.

6. A compound of any preceding Claim, in which Zi-PEG is -O-(PEG)n, in which n is 1 to 5.

7. A compound of any preceding Claim, in which R1is Zi-PEG and one of R3R4R5or R6is Z2-A-M+.

8. A compound of Claims 1 to 5 in which R1is Zi-PEG and one of R3R4R5or R6is Z2-A-M+.

9. A compound of Claims 1 to 5 in which R1is Zi-PEG and R6is Z2-A-M+10. A compound of Claims 1 to 5 in which R1is Z2-A-M+and one of R3R4R5or R6is Zi-PEG.11 . A compound of Claims 1 and 5, which R2is Z2-A-M+and one of R3R4R5or R6is Zi-PEG.

12. A compound of any preceding Claim, in which the compound has antimicrobial activity.

13. A compound of any preceding Claim, selected from the group of:

14. A composition comprising a compound of any preceding claim.

15. Use of compound of any of Claims 1 to 13 or a composition of Claim 14 to treat a surface to kill or inhibit the growth of bacteria on the surface.

16. A pharmaceutical composition comprising a compound of any of Claims 1 to 13 in combination with a suitable pharmaceutical excipient.

17. A compound of any of Claims 1 to 13, for use in a method of treating or preventing a bacterial infection in a subject, in which the method comprises a step of administering a therapeutically effective amount of compound of the compound to the subject.

18. A compound of any of Claims 1 to 13, for use of Claim 17, in which the bacterial infection is a hospital acquired infection.

19. A compound of any of Claims 1 to 13, for use of Claim 17, in which the bacterial infection is selected from an E.coli, MRSA or P. aeruginosa infection.

20. A compound of any of Claims 1 to 13, for use of any of Claims 17 to 19, in which the infection is selected from a urinary tract infection, a surgical site infection, a skin infection, a lung infection, foot infection, diabetic wound infection, a central catheter- related blood circulatory infection, probe-related urinary system infections, bacteraemia, sepsis, severe sepsis, septic shock, secondary meningitis, and ventilator-associated pneumonia in hospital intensive-care units.

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