WO2016112243A1 - Urea derivatives of amphotericin b derived from secondary amines - Google Patents

Abstract

Provided are certain urea derivatives of amphotericin B (AmB) having improved therapeutic index compared to AmB. The compounds of the invention are less toxic than AmB and are useful to treat fungal infections. In certain embodiments the urea derivative of AmB is a compound represented by formula (I) or a pharmaceutically acceptable salt thereof: wherein, independently for each occurrence: R represents methyl, ethyl, propyl, or isopropyl; R' represents methyl, ethyl, propyl, or isopropyl; or R and R', taken together with the nitrogen atom to which they are attached, represent a radical of a cyclic secondary amine. Also provided are methods for making the urea derivatives of AmB.

Description

UREA DERIVATIVES OF AMPHOTERICIN B DERIVED FROM SECONDARY AMINES

RELATED APPLICATION

This application claims the benefit of priority to United States Provisional Patent Application Serial No. 62/101,126, filed January 8, 2015.

GOVERNMENT SUPPORT

This invention was made with Government support under Grant No. GM080436, awarded by the National Institutes of Health. The government has certain rights in the invention.

BACKGROUND OF THE INVENTION

For more than half a century amphotericin B (AmB) has served as the gold standard for treating systemic fungal infections. AmB has a broad spectrum of activity, is fungicidal, and is effective even against fungal strains that are resistant to multiple other agents. Surprisingly, clinically significant microbial resistance has remained exceptionally rare while resistance to next generation antifungals has appeared within just a few years of their clinical introduction. Unfortunately, AmB is also highly toxic. Thus, the effective treatment of systemic fungal infections with AmB is all too often precluded, not by a lack of efficacy, but by dose-limiting side effects. Some progress has been made using liposome delivery systems, but these treatments are prohibitively expensive and significant toxicities remain. Thus, a less toxic but equally effective AmB derivative stands to have a major impact on human health.

SUMMARY OF THE INVENTION

The invention provides certain urea derivatives of AmB having improved therapeutic index compared to AmB. The compounds of the invention are less toxic than AmB and are useful to treat fungal infections.

An aspect of the invention is a compound represented by formula (I) or a pharmaceutically acceptable salt thereof:

(I)

wherein, independently for each occurrence:

R represents methyl, ethyl, propyl, or isopropyl;

R' represents methyl, ethyl, propyl, or isopropyl; or

R and R', taken together with the nitrogen atom to which they are attached, represent a radical of a cyclic secondary amine.

An aspect of the invention is a compound represented by 2 or a pharmaceutically acce table salt thereof:

An aspect of the invention is a compound represented by 4 or a pharmaceutically acceptable salt thereof:

An aspect of the invention is a compound represented by 5 or a pharmaceutically acceptable salt thereof:

An aspect of the invention is a compound represented by 6 or a pharmaceutically acceptable salt thereof:

An aspect of the invention is a compound represented by 7 or a pharmaceutically acceptable salt hereof:

An aspect of the invention is a pharmaceutical composition, comprising a compound of the invention or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable carrier. An aspect of the invention is a method of making a compound represented by formula I) or a pharmaceutically acceptable salt thereof:

(Π)

and a secondary amine, thereby forming a methyl ketal; and

combining the methyl ketal with aqueous acid, thereby forming the compound of formula (I) or a pharmaceutically acceptable salt thereof;

wherein, independently for each occurrence:

R represents methyl, ethyl, propyl, or isopropyl;

R' represents methyl, ethyl, propyl, or isopropyl; or

R and R', taken together with the nitrogen atom to which they are attached, represent a radical of a cyclic secondary amine;

the secondary amine is represented by HN(R)R'; and

P represents a protecting group.

An aspect of the invention is a method of inhibiting growth of a fungus, comprising contacting a fungus with an effective amount of a compound of the invention or a pharmaceutically acceptable salt thereof. An aspect of the invention is a method of treating a fungal infection in a subject, comprising administering to a subject in need thereof a therapeutically effective amount of a compound of the invention or a pharmaceutically acceptable salt thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts synthesis of representative urea derivatives of AmB from oxazolidinone intermediate 1.

DETAILED DESCRIPTION OF THE INVENTION

Amphotericin B (AmB) is a naturally-occurring mycosamine-bearing polyene macrolide represented b

For purposes of this application, AmB can also be represented in a shorthand manner as:

It is used in the treatment of fungal infections, particularly systemic fungal infections, but dosing is frequently limited by systemic toxicity.

A lack of understanding of the mechanism(s) by which AmB is toxic to yeast and human cells has thus far hindered the rational development of a clinically successful derivative. The longstanding accepted mechanism of action of AmB has been ion channel formation within a cell' s membrane leading to electrochemical gradient disruption and eventually cell death. This model suggests that development of a less toxic derivative requires selective ion channel formation in yeast versus human cells. Contrary to this longstanding model, our group recently discovered that the primary mechanism of action of AmB is not ion channel formation, but simple ergosterol binding. Gray, KC et al., Proc Natl Acad Sci USA 109:2234 (2012). Yeast and human cells possess different sterols, ergosterol and cholesterol, respectively. Therefore, the new model suggests a simpler and more actionable roadmap to an improved therapeutic index; i.e., a less toxic AmB derivative would retain potent ergosterol binding capability, but lack the ability to bind cholesterol.

Recently our group reported that removal of the C2' hydroxyl group from the mycosamine sugar produced a derivative, C2'deOAmB, which surprisingly retains ergosterol-binding ability, but shows no binding to cholesterol. Wilcock, BC et al., J Am Chem Soc 135:8488 (2013). Consistent with the preferential sterol binding hypothesis, in vitro studies demonstrated that C2'deOAmB is toxic to yeast, but not human cells.

More recently, our group also developed alternative reduced toxicity AmB derivatives characterized by urea modifications at C16. PCT/US2014/059334, filed October 6, 2014, the contents of which are incorporated herein by reference.

Representative examples of C16 urea derivatives of AmB include AmB methylurea (AmBMU), AmB aminoethylurea (AmBAU), and AmB ethyl carboxylateurea (AmBCU).

AmBAU

OH NH₂

AmBCU

Table 1 summarizes certain in vitro biological activity of AmB and these C16 derivatives.

Table 1.

The amphotericin B (AmB) urea derivatives we have prepared thus far showed no detectable binding to cholesterol, and dramatic decreases in toxicity. Moreover, oxazolidinone 1 represents an easily accessible and highly versatile intermediate, and its surprising reactivity with nucleophiles provides access to many such derivatives using a wide range of commercially available amines. Remarkably, the paradigmatic oxazolidone, 2-oxazolidinone, is unreactive under conditions that lead to formation of AmBMU. Thus, there is substantial opportunity for extensive optimization of the pharmacological properties of this new famil of less toxic amphotericins.

For purposes of this application, oxazolidinone 1 can also be represented in a shorthand manner as:

1

Oxazolidinone 1 is easily synthesized in only three steps from AmB (Example 1). This versatile intermediate can be combined with a variety of secondary amine nucleophiles to open the oxazolidinone ring to form a urea while concomitantly cleaving the Fmoc protecting group. Upon HPLC purification and workup under acidic aqueous conditions, the methyl ketal is cleaved to a hemiketal, revealing the final AmB urea compounds. Using this strategy a number of secondary ureas have been synthesized including: AmB dimethylurea (2), AmB diethylurea (3), AmB diisopropylurea (4), AmB piperdinourea (5), AmB morpholinourea (6), and AmB N-methylpiperazinourea (7). Many of these urea derivatives maintain antifungal activity. Moreover, for example, compounds 6 and 7 are dramatically less toxic than AmB, not causing red blood cell hemolysis even at 500 μΜ.

Compounds

An aspect of the invention is a compound or a pharmaceutically acceptable salt thereof represented by formula (I)

R and R', taken together with the nitrogen atom to which they are attached, represent a radical of a cyclic secondary amine.

In certain embodiments, R and R' independently represent straight- or branched- chain (Ci-C₈)alkyl.

In certain embodiments, R and R' independently represent methyl, ethyl, propyl, or isopropyl.

In certain embodiments, R and R', taken together with the nitrogen atom to which they are attached, represent a radical of a cyclic secondary amine.

In certain embodiments, the cyclic amine is selected from the group consisting of substituted and unsubstituted 3-7-membered nitrogen-containing rings with 0 to 2 additional ring heteroatoms independently selected from the group consisting of N, O, and S.

In certain embodiments, the cyclic amine is selected from the group consisting of piperidine, piperazine, 1-methylpiperazine, and morpholine.

In certain embodiments, the cyclic amine is selected from the group consisting of piperidine, 1-methylpiperazine, and morpholine.

In certain embodiments, the compound is represented by 2 or a pharmaceutically acceptable salt thereof:

In certain embodiments, the compound is represented by 3 or a pharmaceutically acceptable salt thereof:

In certain embodiments, the compound is represented by 4 or a pharmaceutically acceptable salt thereof:

In certain embodiments, the compound is represented by 5 or a pharmaceutically acceptable salt thereof:

In certain embodiments, the compound is represented by 6 or a pharmaceutically acceptable salt thereof:

In certain embodiments, the compound is represented by 7 or a pharmaceutically acceptable salt thereof:

Definitions

The term "alkyl" is art-recognized, and includes saturated aliphatic groups, including straight-chain alkyl groups, branched-chain alkyl groups, cycloalkyl (alicyclic) groups, alkyl substituted cycloalkyl groups, and cycloalkyl substituted alkyl groups. In certain embodiments, a straight-chain or branched-chain alkyl has about 30 or fewer carbon atoms in its backbone (e.g., C1-C30 for straight chain, C3-C30 for branched chain), and alternatively, about 20 or fewer. Likewise, cycloalkyls have from about 3 to about 10 carbon atoms in their ring structure, and alternatively about 5, about 6, or about 7 carbons in the ring structure.

The terms "alkenyl" and "alkynyl" are art-recognized and refer to unsaturated aliphatic groups analogous in length and possible substitution to the alkyls described above, but that contain at least one double or triple bond respectively.

Unless the number of carbons is otherwise specified, "lower alkyl" refers to an alkyl group, as defined above, but having from one to about ten carbons, alternatively from one to about six carbon atoms in its backbone structure. Likewise, "lower alkenyl" and "lower alkynyl" have similar chain lengths.

The term "aralkyl" is art-recognized and refers to an alkyl group substituted with an aryl group (i.e., an aromatic or heteroaromatic group).

The term "aryl" is art-recognized and refers to 5-, 6- and 7-membered single-ring aromatic groups that may include from zero to four heteroatoms, for example, benzene, naphthalene, anthracene, pyrene, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine, pyridazine and pyrimidine, and the like. Those aryl groups having heteroatoms in the ring structure may also be referred to as "aryl

heterocycles" or "heteroaromatics." The aromatic ring may be substituted at one or more ring positions with such substituents as, for example, halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino, nitro, sulfhydryl, imino, amido,

phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, sulfonamido, ketone, aldehyde, ester, heterocyclyl, aromatic or heteroaromatic moieties, -CF₃, -CN, or the like. The term "aryl" also includes polycyclic ring systems having two or more cyclic rings in which two or more carbons are common to two adjoining rings (the rings are "fused rings") wherein at least one of the rings is aromatic, e.g., the other cyclic rings may be cycloalkyls, cycloalkenyls, cycloalkynyls, aryls and/or heterocyclyls.

The term "heteroatom" is art-recognized and refers to an atom of any element other than carbon or hydrogen. Illustrative heteroatoms include boron, nitrogen, oxygen, phosphorus, sulfur and selenium.

The term "nitro" is art-recognized and refers to -N0₂.

The term "halogen" is art-recognized and refers to -F, -CI, -Br or -I.

The term "sulfhydryl" is art-recognized and refers to -SH.

The term "hydroxyl" is art-recognized and refers -OH.

The term "sulfonyl" is art-recognized and refers to -S0₂ ^".

The terms "amine" and "amino" are art-recognized and refer to both unsubstituted and substituted amines, e.g., a moiety that may be represented by the general formulas:

R50

R50

/

N N R53

\ I

^{R5 1} R52

wherein R50, R51 and R52 each independently represent a hydrogen, an alkyl, an alkenyl, -(CH₂)_m-R61, or R50 and R51, taken together with the N atom to which they are attached complete a heterocycle having from 4 to 8 atoms in the ring structure; R61 represents an aryl, a cycloalkyl, a cycloalkenyl, a heterocycle or a polycycle; and m is zero or an integer in the range of 1 to 8. In other embodiments, R50 and R51 (and optionally R52) each independently represent a hydrogen, an alkyl, an alkenyl, or -(CH₂)_m-R61. Thus, the term "alkylamine" includes an amine group, as defined above, having a substituted or unsubstituted alkyl attached thereto, i.e., at least one of R50 and R51 is an alkyl group.

Examples of amines include, without limitation, 1-(1-Naphthyl)ethylamine; l-(2- Naphthyl)ethylamine; l-(4-Bromophenyl)ethylamine; l, l-Diphenyl-2-aminopropane; 1,2,2- Triphenylethylamine; 1 ,2,3 ,4-Tetrahydro- 1 -naphthylamine; 1 ,2-Bis(2- hydroxyphenyl)ethylenediamine; l-Amino-2-benzyloxycyclopentane; 1-Aminoindane; 1- Benzyl-2,2-diphenylethylamine; 1-Cyclopropylethylamine; 1-Phenylbutylamine; 2-(3- Chloro-2,2-dimethyl-propionylamino)-3-methylbutanol; 2-

(Dibenzylamino)propionaldehyde; 2,2-Dimethyl-5-methylamino-4-phenyl-l,3-dioxane; 2- Amino- 1 -fluoro-4-methyl- 1 , 1 -diphenylpentane; 2-Amino-3 ,3 -dimethyl- 1 , 1 -diphenylbutane; 2- Amino-3 -methyl- 1 , 1 -diphenylbutane; 2- Amino-3 -methylbutane; 2- Amino-4-methyl- 1,1- diphenylpentane; 2-Aminoheptane; 2-Aminohexane; 2-Aminononane; 2-Aminooctane; 2- Chloro-6-fluorobenzylamine; 2-Methoxy-a-methylbenzylamine; 2-Methyl-l-butylamine; 2- Methylbutylamine; 3,3-Dimethyl-2-butylamine; 3,4-Dimethoxy-a-methylbenzylamine; 3- Amino-2-(hydroxymethyl)propionic acid; 3-Bromo-a-methylbenzylamine; 3-Chloro-a- methylbenzylamine; 4-Chloro-a-methylbenzylamine; 4-Cyclohexene-l,2-diamine; 4- Fluoro-a-methylbenzylamine; 4-Methoxy-a-methylbenzylamine; 7-Amino-5, 6,7,8- tetrahydro-2-naphthol; Bis[l-phenylethyl]amine; Bornylamine; cis-2-Aminocyclopentanol hydrochloride; cis-Myrtanylamine; cis-N-Boc-2-aminocyclopentanol;

Isopinocampheylamine; L-Allysine ethylene acetal; Methyl 3-aminobutyrate p- toluenesulfonate salt; N,N'-Dimethyl-l,l '-binaphthyldiamine; N,N-Dimethyl-1-(1- naphthyl)ethylamine; N,N-Dimethyl-l-phenylethylamine; Ν,α-Dimethylbenzylamine; N- allyl-a-methylbenzylamine; N-Benzyl-a-methylbenzylamine; sec-Butylamine; trans-2- (Aminomethyl)cyclohexanol; trans-2- Amino- 1,2-dihydro-l-naphthol hydrochloride; trans- 2-Benzyloxycyclohexylamine; a,4-Dimethylbenzylamine; a-Ethylbenzylamine; a- Methylbenzylamine; and β-Methylphenethylamine.

Secondary amines include, without limitation, a-(methylaminomethyl)benzyl alcohol, 1-methylpiperazine, 1,2,3,4-tetrahydrocarbazole, 1,2,3,4-tetrahydroisoquinoline, 1,2,3,4-tetrahydroquinoline, 1,2,3, 6-tetrahydropyridine, 1,2-dianilinoethane, 1,3,3- trimethyl-6-azabicyclo[3.2.1]octane, l,3-bis[tris(hydroxymethyl)methylamino]propane, l,4,10, 13-tetraoxa-7, 16-diazacyclooctadecane, 1,4,7-triazacyclononane, 1,4,8, 11- tetraazacyclotetradecane, 1,4,8, 12-tetraazacyclopentadecane, l,4-dioxa-8- azaspiro[4.5]decane, 1,5,9-triazacyclododecane, 2,2,6,6-tetramethylpiperidine, 2,2,6,6- trimethyl-4-piperidinol, 2,2'-dithiobis(l-naphthalene), 2,3-dimethylindoline, 2,3- dimethylpiperazine, 2,4,6-tri-tert-butyl-N-methylaniline, 2,5-dimethyl-3-pyrroline, 2,5- dimethylpiperazine, 2,5-dimethylpyrrolidine, 2,6-dimethylmorpholine, 2,6- dimethylpiperazine, 2,6-dimethylpiperidine, 2-anilinoethanol, 2-benzylaniline, 2- methylaziridine, 2-methylindoline, 2-methylpiperazine, 2-methylpiperidine, 2- methylpyrrolidine, 2-piperidine ethanol, 2-piperidinemethanol, 2-pyrrolidinemethanol, 3,3- dimethylpiperidine, 3,4-dimethoxypyrrolidine, 3,5-dimethylpiperidine, 3-hydroxy piped dine, 3-methylpiperidine, 3 -piped dine methanol, 3-pyrrolidinol, 3-pyrroline, 4,4'- bipiperidine, 4,4-difluoropiperidine, 4,4-dimethyloxazolidine, 4-chloro-N-methylaniline, 4- ethyl-2-methyl-2-(3-methylbutyl)oxazolidine, 4-hydroxy piped dine, 4-methylpiperidine, 4- phenyl-l,2,3,6-tetrahydropyridine, 5,6, 1 l,12-tetrahydrodibenz[B,F]azocine, 6- (dimethylamino)fulvene, 6,7-dimethoxy-l,2,3,4-tetrahydroisoquinoline, 7,7,9,9- tetramethyl-l,4-dioxa-8-azaspiro[4.5]decane-2-methanol, azetidine, benzimidazoles, bipyridines, bis(2-ethylhexyl)amine, bis(2-methoxyethyl)amine, bis(trimethylsilyl)amine, carbazoles, [duplicate]di(3-ethoxypropyl)amine, diallylamine, diamylamine,

dibenzylamine, dibutylamine, dicyclohexylamine, didecylamine, diethanolamine, diethylamine, diheptylamine, dihexylamine, diisobutylamine, diisopropanolamine, diisopropylamine, dimethylamine, dioctylamine, dipentylamine, diphenylamine, dipropylamine, di-sec-butanolamine, di-sec-butylamine, di-tert-butylamine,

ethylbutylamine, ethylmethylamine, ethylpropylamine, heptamethyleneimine,

hexamethyleneimine, homopiperazine, imidazole, imidazolines, iminodibenzyl, indole, indoline, indoline-2-carboxylic acid, methyl aminoacetal dehyde dimethylacetal, morpholine, Ν,α-dimethylbenzylamine, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N'-bis(3,3- dimethylbutyl)- 1 ,2-cyclohexanediamine, N,N-di-(n-nonyl)amine, N,N-di-(sec-butyl)amine, Ν,Ν'-dibenzylethylenediamine, N,N'-diethyl-l,3-propanediamine, N,N'-diethyl-2-butylene- 1,4-diamine, N,N'-diisopropyl-l,3-propanediamine, N,N'-diisopropylethylenediamine, Ν,Ν'-dimethyl- 1 ,3 -propanediamine, Ν,Ν' -dimethyl- 1 ,6-hexanediamine, Ν,Ν'-diphenyl- 1 ,4- phenylenediamine, N,N'-diphenylbenzidine, N-alkylmo holines, N-alkylpiperazine, N- allylaniline, N-allylcyclopentylamine, N-benzyl-a-methylbenzylamine, N-benzyl-2- phenethylamine, N-benzylaniline, N-benzylethanolamine, N-benzylmethylamine, N- benzyl-tert-butylamine, N-butylaniline, (N-butyl)methylamine, N-ethyl-2,3-xylidine, N- ethyl-3,4-(methylenedioxy)aniline, N-ethylaniline, N-ethylbenzylmethylamine, N- ethylbutylamine, N-ethylcyclohexylamine, N-ethylisopropylamine, N-ethyl-m-toluidine, N- ethyl-o-toluidine, N-ethyl-p-toluidine, N-isopropylbenzylmethylamine, N- isopropylcyclohexylamine, N-isopropyl-N-isobutylamine, N-methyl-2-methylallylamine, N-methylallylamine, N-methylaniline, N-methylcyclohexylamine, N-methylglucamine, N- methylhexylamine, N-methylisopropylamine, N-methyloctadecylamine, N-methyl-p- anisidine, N-methylphenethylamine, N-methylpropylamine, N-phenylbenzylamine, N- propylcyclopropanemethylamine, N-tert-butylcyclohexylamine, N-tert- butylisopropylamine, phenothiazine, piperazine, piperidine, propylbutylamine, pyrazoles, pyrazolines, pyrroles, pyrrolidine, pyrrolidinones, tert-amyl-tert-butylamine, tert-amyl-tert- octylamine, tert-butyl-ethylamine, tert-butylmethylamine, tetrazoles, thiazolidine, thiomorpholine, and triazoles.

The term "amido" is art recognized as an amino-substituted carbonyl and includes a moiety that may be represented by the general formula: 1

wherein R50 and R51 are as defined above. Certain embodiments of the amide in the present invention will not include imides which may be unstable.

The terms "alkoxyl" or "alkoxy" are art-recognized and refer to an alkyl group, as defined above, having an oxygen radical attached thereto. Representative alkoxyl groups include methoxy, ethoxy, propyloxy, tert-butoxy and the like.

Pharmaceutical Compositions

Also provided are pharmaceutical compositions, comprising a compound of the invention or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable carrier. Also provided is a method for making such pharmaceutical compositions. The method comprises combining a compound of the invention or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

In certain embodiments, the pharmaceutical composition is a parenteral or oral dosage form.

In certain embodiments, the pharmaceutical composition is a parenteral dosage form.

In certain embodiments, the pharmaceutical composition is an intravenous dosage form.

In certain embodiments, the pharmaceutical composition is an oral dosage form.

Compounds of the invention and pharmaceutical compositions of the invention are useful for inhibiting the growth of a fungus. In one embodiment, an effective amount of a compound of the invention is contacted with a fungus, thereby inhibiting growth of the fungus. In one embodiment, a compound of the invention, or a pharmaceutically acceptable salt thereof, is added to or included in tissue culture medium. Methods of Making

An aspect of the invention is a method of making a compound represented by formula I) or a pharmaceutically acceptable salt thereof:

(Π)

and a secondary amine, thereby forming a methyl ketal; and

combining the methyl ketal with aqueous acid, thereby forming the compound of formula (I) or a pharmaceutically acceptable salt thereof;

wherein, independently for each occurrence:

R and R' independently represent straight- or branched-chain alkyl, cycloalkyl, cycloalkylalkyl, heterocyclyl, aryl, heteroaryl, aralkyl, or heteroaralkyl; or

R and R', taken together with the nitrogen atom to which they are attached, represent a radical of a cyclic secondary amine;

the secondary amine is represented by HN(R)R' ; and

P represents a protecting group.

In certain embodiments, the secondary amine is selected from the group consisting of dimethylamine, diethylamine, and diisopropylamine. In certain embodiments, R and R' independently represent straight- or branched- chain (Ci-C8)alkyl.

In certain embodiments, R and R' independently represent methyl, ethyl, propyl, or isopropyl.

In certain embodiments, the secondary amine is a cyclic secondary amine.

In certain embodiments, the cyclic secondary amine is selected from the group consisting of substituted and unsubstituted 3-7-membered nitrogen-containing rings with 0 to 2 additional ring heteroatoms independently selected from the group consisting of N, O, and S.

In certain embodiments, the cyclic secondary amine is selected from the group consisting of piped dine, piperazine, 1-methylpiperazine, and morpholine.

In certain embodiments, the cyclic secondary amine is selected from the group consisting of piped dine, 1-methylpiperazine, and morpholine.

In certain embodiments, the cyclic secondary amine is piperidine.

In certain embodiments, the cyclic secondary amine is 1-methylpiperazine.

In certain embodiments, the cyclic secondary amine is morpholine.

In certain embodiments, protecting group P is selected from the group consisting of 9-fluorenylmethyloxycarbonyl (Fmoc), t-butyloxycarbonyl (t-Boc or oc), p- methoxybenzylcarbonyl, carbobenzyloxy (Cbz), acetyl, triflouroacetyl, phthalyl, benzoyl, benzyl, /?-methoxybenzyl, 3,4-dimethoxybenzyl, benzylidenyl, and^-toluenesulfonyl (Tosyl).

In certain embodiments, protecting group P is Fmoc. Methods of Use

Compounds of the invention are useful for inhibiting growth of fungi. An aspect of the invention is a method of inhibiting growth of a fungus, comprising contacting a fungus with an effective amount of a compound of the invention.

Compounds of the invention and pharmaceutical compositions of the invention are useful for the treatment of fungal infections in a subject. In one embodiment, a

therapeutically effective amount of a compound of the invention, or a pharmaceutically acceptable salt thereof, is administered to a subject in need thereof, thereby treating the fungal infection.

In certain embodiments, the compound is administered parenterally or orally. In certain embodiments, the compound is administered parenterally.

In certain embodiments, the compound is administered intravenously.

In certain embodiments, the compound is administered orally.

A fungus is a eukaryotic organism classified in the kingdom Fungi. Fungi include yeasts, molds, and larger organisms including mushrooms. Yeasts and molds are of clinical relevance as infectious agents.

Yeasts are eukaryotic organisms classified in the kingdom Fungi. Yeasts are typically described as budding forms of fungi. Of particular importance in connection with the invention are species of yeast that can cause infections in mammalian hosts. Such infections most commonly occur in immunocompromised hosts, including hosts with compromised barriers to infection (e.g., burn victims) and hosts with compromised immune systems (e.g., hosts receiving chemotherapy or immune suppressive therapy, and hosts infected with HIV). Pathogenic yeasts include, without limitation, various species of the genus Candida, as well as of Cryptococcus . Of particular note among pathogenic yeasts of the genus Candida are C albicans, C tropicalis, C stellatoidea, C. glabrata, C. krusei, C. parapsilosis, C. guilliermondii, C. viswanathii, and C. lusitaniae. The genus

Cryptococcus specifically includes Cryptococcus neoformans. Yeast can cause infections of mucosal membranes, for example oral, esophageal, and vaginal infections in humans, as well as infections of bone, blood, urogenital tract, and central nervous system. This list is exemplary and is not limiting in any way.

A number of fungi (apart from yeast) can cause infections in mammalian hosts. Such infections most commonly occur in immunocompromised hosts, including hosts with compromised barriers to infection (e.g., burn victims) and hosts with compromised immune systems (e.g., hosts receiving chemotherapy or immune suppressive therapy, and hosts infected with HIV). Pathogenic fungi (apart from yeast) include, without limitation, species of Aspergillus, Rhizopus, Mucor, Histoplasma, Coccidioides, Blastomyces, Trichophyton, Microsporum, and Epidermophyton. Of particular note among the foregoing are A.

fumigatus, A. flavus, A. niger, H. capsulatum, C immitis, and B. dermatitidis. Fungi can cause systemic and deep tissue infections in lung, bone, blood, urogenital tract, and central nervous system, to name a few. Some fungi are responsible for infections of the skin and nails.

As used herein, "inhibit" or "inhibiting" means reduce by an objectively

measureable amount or degree compared to control. In one embodiment, inhibit or inhibiting means reduce by at least a statistically significant amount compared to control.

In one embodiment, inhibit or inhibiting means reduce by at least 5 percent compared to control. In various individual embodiments, inhibit or inhibiting means reduce by at least

10, 15, 20, 25, 30, 33, 40, 50, 60, 67, 70, 75, 80, 90, or 95 percent (%) compared to control.

As used herein, the terms "treat" and "treating" refer to performing an intervention that results in (a) preventing a condition or disease from occurring in a subject that may be at risk of developing or predisposed to having the condition or disease but has not yet been diagnosed as having it; (b) inhibiting a condition or disease, e.g., slowing or arresting its development; or (c) relieving or ameliorating a condition or disease, e.g., causing regression of the condition or disease. In one embodiment the terms "treating" and "treat" refer to performing an intervention that results in (a) inhibiting a condition or disease, e.g., slowing or arresting its development; or (b) relieving or ameliorating a condition or disease, e.g., causing regression of the condition or disease.

A "fungal infection" as used herein refers to an infection in or of a subject with a fungus as defined herein. In one embodiment the term "fungal infection" includes a yeast infection. A "yeast infection" as used herein refers to an infection in or of a subject with a yeast as defined herein.

As used herein, a "subject" refers to a living mammal. In various embodiments a subject is a non-human mammal, including, without limitation, a mouse, rat, hamster, guinea pig, rabbit, sheep, goat, cat, dog, pig, horse, cow, or non-human primate. In one embodiment a subject is a human.

As used herein, a "subject having a yeast or fungal infection" refers to a subject that exhibits at least one objective manifestation of a yeast or fungal infection. In one embodiment a subject having a yeast or fungal infection is a subject that has been diagnosed as having a yeast or fungal infection and is in need of treatment thereof.

Methods of diagnosing a yeast or fungal infection are well known and need not be described here in any detail.

As used herein, "administering" has its usual meaning and encompasses

administering by any suitable route of administration, including, without limitation, intravenous, intramuscular, intraperitoneal, intrathecal, intraocular (e.g., intravitreal), subcutaneous, direct injection (for example, into a tumor), mucosal, inhalation, oral, and topical.

In one embodiment, the administration is intravenous. In one embodiment, the administration is oral.

As used herein, the phrase "effective amount" refers to any amount that is sufficient to achieve a desired biological effect.

As used herein, the phrase "therapeutically effective amount" refers to an amount that is sufficient to achieve a desired therapeutic effect, e.g., to treat a yeast or fungal infection.

Compounds of the invention can be combined with other therapeutic agents. The compound of the invention and other therapeutic agent may be administered simultaneously or sequentially. When the other therapeutic agents are administered simultaneously, they can be administered in the same or separate formulations, but they are administered substantially at the same time. The other therapeutic agents are administered sequentially with one another and with compound of the invention, when the administration of the other therapeutic agents and the compound of the invention is temporally separated. The separation in time between the administration of these compounds may be a matter of minutes or it may be longer.

Examples of other therapeutic agents include other antifungal agents, including AmB, as well as other antibiotics, anti-viral agents, anti-inflammatory agents,

immunosuppressive agents, and anti-cancer agents.

As stated above, an "effective amount" refers to any amount that is sufficient to achieve a desired biological effect. Combined with the teachings provided herein, by choosing among the various active compounds and weighing factors such as potency, relative bioavailability, patient body weight, severity of adverse side-effects and preferred mode of administration, an effective prophylactic or therapeutic treatment regimen can be planned which does not cause substantial unwanted toxicity and yet is effective to treat the particular subject. The effective amount for any particular application can vary depending on such factors as the disease or condition being treated, the particular compound of the invention being administered, the size of the subject, or the severity of the disease or condition. One of ordinary skill in the art can empirically determine the effective amount of a particular compound of the invention and/or other therapeutic agent without necessitating undue experimentation. It is preferred generally that a maximum dose be used, that is, the highest safe dose according to some medical judgment. Multiple doses per day may be contemplated to achieve appropriate systemic levels of compounds.

Appropriate systemic levels can be determined by, for example, measurement of the patient's peak or sustained plasma level of the drug. "Dose" and "dosage" are used interchangeably herein.

Generally, daily oral doses of active compounds will be, for human subjects, from about 0.01 milligrams/kg per day to 1000 milligrams/kg per day. It is expected that oral doses in the range of 0.5 to 50 milligrams/kg, in one or several administrations per day, will yield the desired results. Dosage may be adjusted appropriately to achieve desired drug levels, local or systemic, depending upon the mode of administration. For example, it is expected that intravenous administration would be from one order to several orders of magnitude lower dose per day. In the event that the response in a subject is insufficient at such doses, even higher doses (or effective higher doses by a different, more localized delivery route) may be employed to the extent that patient tolerance permits. Multiple doses per day are contemplated to achieve appropriate systemic levels of compounds.

In one embodiment, intravenous administration of a compound of the invention may typically be from 0.1 mg/kg/day to 20 mg/kg/day. Intravenous dosing thus may be similar to, or advantageously, may exceed maximal tolerated doses of AmB.

For any compound described herein the therapeutically effective amount can be initially determined from animal models. A therapeutically effective dose can also be determined from human data for compounds of the invention which have been tested in humans and for compounds which are known to exhibit similar pharmacological activities, such as other related active agents. Higher doses may be required for parenteral administration. The applied dose can be adjusted based on the relative bioavailability and potency of the administered compound. Adjusting the dose to achieve maximal efficacy based on the methods described above and other methods as are well-known in the art is well within the capabilities of the ordinarily skilled artisan.

The formulations of the invention are administered in pharmaceutically acceptable solutions, which may routinely contain pharmaceutically acceptable concentrations of salt, buffering agents, preservatives, compatible carriers, adjuvants, and optionally other therapeutic ingredients.

Amphotericin B is commercially available in a number of formulations, including deoxycholate-based formulations and lipid-based (including liposomal) formulations.

Amphotericin B derivative compounds of the invention similarly may be formulated, for example, and without limitation, as deoxycholate-based formulations and lipid-based (including liposomal) formulations. For use in therapy, an effective amount of the compound of the invention can be administered to a subject by any mode that delivers the compound of the invention to the desired surface. Administering the pharmaceutical composition of the present invention may be accomplished by any means known to the skilled artisan. Routes of administration include but are not limited to oral, intravenous, intramuscular, intraperitoneal,

subcutaneous, direct injection (for example, into a tumor or abscess), mucosal, inhalation, and topical.

For oral administration, the compounds (i.e., compounds of the invention, and other therapeutic agents) can be formulated readily by combining the active compound(s) with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a subject to be treated. Pharmaceutical preparations for oral use can be obtained as solid excipient, optionally grinding a resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets or dragee cores. Suitable excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol; cellulose preparations such as, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone (PVP). If desired, disintegrating agents may be added, such as the cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof such as sodium alginate. Optionally the oral formulations may also be formulated in saline or buffers, e.g., EDTA for neutralizing internal acid conditions or may be administered without any carriers.

Also specifically contemplated are oral dosage forms of the above component or components. The component or components may be chemically modified so that oral delivery of the derivative is efficacious. Generally, the chemical modification

contemplated is the attachment of at least one moiety to the component molecule itself, where said moiety permits (a) inhibition of acid hydrolysis; and (b) uptake into the blood stream from the stomach or intestine. Also desired is the increase in overall stability of the component or components and increase in circulation time in the body. Examples of such moieties include: polyethylene glycol, copolymers of ethylene glycol and propylene glycol, carboxymethyl cellulose, dextran, polyvinyl alcohol, polyvinyl pyrrolidone and polyproline. Abuchowski and Davis, "Soluble Polymer-Enzyme Adducts", In: Enzymes as Drugs, Hocenberg and Roberts, eds., Wiley-Interscience, New York, N.Y., pp. 367-383 (1981);

Newmark et al., J Appl Biochem 4: 185-9 (1982). Other polymers that could be used are poly-l,3-dioxolane and poly-l,3,6-tioxocane. Preferred for pharmaceutical usage, as indicated above, are polyethylene glycol moieties.

For the component (or derivative) the location of release may be the stomach, the small intestine (the duodenum, the jejunum, or the ileum), or the large intestine. One skilled in the art has available formulations which will not dissolve in the stomach, yet will release the material in the duodenum or elsewhere in the intestine. Preferably, the release will avoid the deleterious effects of the stomach environment, either by protection of the compound of the invention (or derivative) or by release of the biologically active material beyond the stomach environment, such as in the intestine.

To ensure full gastric resistance a coating impermeable to at least pH 5.0 is essential. Examples of the more common inert ingredients that are used as enteric coatings are cellulose acetate trimellitate (CAT), hydroxypropylmethylcellulose phthalate (HPMCP), HPMCP 50, HPMCP 55, polyvinyl acetate phthalate (PVAP), Eudragit L30D, Aquateric, cellulose acetate phthalate (CAP), Eudragit L, Eudragit S, and shellac. These coatings may be used as mixed films.

A coating or mixture of coatings can also be used on tablets, which are not intended for protection against the stomach. This can include sugar coatings, or coatings which make the tablet easier to swallow. Capsules may consist of a hard shell (such as gelatin) for delivery of dry therapeutic (e.g., powder); for liquid forms, a soft gelatin shell may be used.

The shell material of cachets could be thick starch or other edible paper. For pills, lozenges, molded tablets or tablet triturates, moist massing techniques can be used.

The therapeutic can be included in the formulation as fine multi-particulates in the form of granules or pellets of particle size about 1 mm. The formulation of the material for capsule administration could also be as a powder, lightly compressed plugs or even as tablets. The therapeutic could be prepared by compression.

Colorants and flavoring agents may all be included. For example, the compound of the invention (or derivative) may be formulated (such as by liposome or microsphere encapsulation) and then further contained within an edible product, such as a refrigerated beverage containing colorants and flavoring agents.

One may dilute or increase the volume of the therapeutic with an inert material.

These diluents could include carbohydrates, especially mannitol, a-lactose, anhydrous lactose, cellulose, sucrose, modified dextrans and starch. Certain inorganic salts may be also be used as fillers including calcium triphosphate, magnesium carbonate and sodium chloride. Some commercially available diluents are Fast-Flo, Emdex, STA-Rx 1500, Emcompress and Avicell.

Disintegrants may be included in the formulation of the therapeutic into a solid dosage form. Materials used as disintegrates include but are not limited to starch, including the commercial disintegrant based on starch, Explotab. Sodium starch glycolate,

Amberlite, sodium carboxymethylcellulose, ultramylopectin, sodium alginate, gelatin, orange peel, acid carboxymethyl cellulose, natural sponge and bentonite may all be used. Another form of the disintegrants are the insoluble cationic exchange resins. Powdered gums may be used as disintegrants and as binders and these can include powdered gums such as agar, Karaya or tragacanth. Alginic acid and its sodium salt are also useful as disintegrants.

Binders may be used to hold the therapeutic agent together to form a hard tablet and include materials from natural products such as acacia, tragacanth, starch and gelatin.

Others include methyl cellulose (MC), ethyl cellulose (EC) and carboxymethyl cellulose (CMC). Polyvinyl pyrrolidone (PVP) and hydroxypropylmethyl cellulose (FIPMC) could both be used in alcoholic solutions to granulate the therapeutic.

An anti-frictional agent may be included in the formulation of the therapeutic to prevent sticking during the formulation process. Lubricants may be used as a layer between the therapeutic and the die wall, and these can include but are not limited to; stearic acid including its magnesium and calcium salts, polytetrafluoroethylene (PTFE), liquid paraffin, vegetable oils and waxes. Soluble lubricants may also be used such as sodium lauryl sulfate, magnesium lauryl sulfate, polyethylene glycol of various molecular weights, Carbowax 4000 and 6000.

Glidants that might improve the flow properties of the drug during formulation and to aid rearrangement during compression might be added. The glidants may include starch, talc, pyrogenic silica and hydrated silicoaluminate.

To aid dissolution of the therapeutic into the aqueous environment a surfactant might be added as a wetting agent. Surfactants may include anionic detergents such as sodium lauryl sulfate, dioctyl sodium sulfosuccinate and dioctyl sodium sulfonate. Cationic detergents which can be used and can include benzalkonium chloride and benzethonium chloride. Potential non-ionic detergents that could be included in the formulation as surfactants include lauromacrogol 400, polyoxyl 40 stearate, polyoxyethylene hydrogenated castor oil 10, 50 and 60, glycerol monostearate, polysorbate 40, 60, 65 and 80, sucrose fatty acid ester, methyl cellulose and carboxymethyl cellulose. These surfactants could be present in the formulation of the compound of the invention or derivative either alone or as a mixture in different ratios.

Pharmaceutical preparations which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with filler such as lactose, binders such as starches, and/or lubricants such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. In addition, stabilizers may be added. Microspheres formulated for oral administration may also be used. Such microspheres have been well defined in the art. All formulations for oral administration should be in dosages suitable for such

administration.

For buccal administration, the compositions may take the form of tablets or lozenges formulated in conventional manner.

For administration by inhalation, the compounds for use according to the present invention may be conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebulizer, with the use of a suitable propellant, e.g.,

dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges of e.g., gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.

Also contemplated herein is pulmonary delivery of the compounds of the invention (or derivatives thereof). The compound of the invention (or derivative) is delivered to the lungs of a mammal while inhaling and traverses across the lung epithelial lining to the blood stream. Other reports of inhaled molecules include Adjei et al., Pharm Res 7:565- 569 (1990); Adjei et al., Int J Pharmaceutics 63 : 135-144 (1990) (leuprolide acetate);

Braquet et al., J Cardiovasc Pharmacol 13(suppl. 5): 143-146 (1989) (endothelin-1);

Hubbard et al., Annal Int Med 3 :206-212 (1989) (a 1 -antitrypsin); Smith et al., 1989, J Clin Invest 84: 1145-1146 (a- 1 -proteinase); Oswein et al., 1990, "Aerosolization of Proteins", Proceedings of Symposium on Respiratory Drug Delivery II, Keystone, Colorado, March, (recombinant human growth hormone); Debs et al., 1988, J Immunol 140:3482-3488 (interferon-gamma and tumor necrosis factor alpha) and Platz et al., U.S. Pat. No.

5,284,656 (granulocyte colony stimulating factor). A method and composition for pulmonary delivery of drugs for systemic effect is described in U.S. Pat. No. 5,451,569, issued Sep. 19, 1995 to Wong et al.

Contemplated for use in the practice of this invention are a wide range of mechanical devices designed for pulmonary delivery of therapeutic products, including but not limited to nebulizers, metered dose inhalers, and powder inhalers, all of which are familiar to those skilled in the art.

Some specific examples of commercially available devices suitable for the practice of this invention are the Ultravent nebulizer, manufactured by Mallinckrodt, Inc., St. Louis, Mo.; the Acorn II nebulizer, manufactured by Marquest Medical Products, Englewood, Colo.; the Ventolin metered dose inhaler, manufactured by Glaxo Inc., Research Triangle Park, North Carolina; and the Spinhaler powder inhaler, manufactured by Fisons Corp., Bedford, Mass.

All such devices require the use of formulations suitable for the dispensing of compound of the invention (or derivative). Typically, each formulation is specific to the type of device employed and may involve the use of an appropriate propellant material, in addition to the usual diluents, adjuvants and/or carriers useful in therapy. Also, the use of liposomes, microcapsules or microspheres, inclusion complexes, or other types of carriers is contemplated. Chemically modified compound of the invention may also be prepared in different formulations depending on the type of chemical modification or the type of device employed.

Formulations suitable for use with a nebulizer, either jet or ultrasonic, will typically comprise compound of the invention (or derivative) dissolved in water at a concentration of about 0.1 to 25 mg of biologically active compound of the invention per mL of solution. The formulation may also include a buffer and a simple sugar (e.g., for compound of the invention stabilization and regulation of osmotic pressure). The nebulizer formulation may also contain a surfactant, to reduce or prevent surface induced aggregation of the compound of the invention caused by atomization of the solution in forming the aerosol.

Formulations for use with a metered-dose inhaler device will generally comprise a finely divided powder containing the compound of the invention (or derivative) suspended in a propellant with the aid of a surfactant. The propellant may be any conventional material employed for this purpose, such as a chlorofluorocarbon, a

hydrochlorofluorocarbon, a hydrofluorocarbon, or a hydrocarbon, including

trichlorofluoromethane, dichlorodifluoromethane, dichlorotetrafluoroethanol, and 1, 1,1,2- tetrafluoroethane, or combinations thereof. Suitable surfactants include sorbitan trioleate and soya lecithin. Oleic acid may also be useful as a surfactant.

Formulations for dispensing from a powder inhaler device will comprise a finely divided dry powder containing compound of the invention (or derivative) and may also include a bulking agent, such as lactose, sorbitol, sucrose, or mannitol in amounts which facilitate dispersal of the powder from the device, e.g., 50 to 90% by weight of the formulation. The compound of the invention (or derivative) should advantageously be prepared in particulate form with an average particle size of less than 10 micrometers (μπι), most preferably 0.5 to 5 μπι, for most effective delivery to the deep lung.

Nasal delivery of a pharmaceutical composition of the present invention is also contemplated. Nasal delivery allows the passage of a pharmaceutical composition of the present invention to the blood stream directly after administering the therapeutic product to the nose, without the necessity for deposition of the product in the lung. Formulations for nasal delivery include those with dextran or cyclodextran.

For nasal administration, a useful device is a small, hard bottle to which a metered dose sprayer is attached. In one embodiment, the metered dose is delivered by drawing the pharmaceutical composition of the present invention solution into a chamber of defined volume, which chamber has an aperture dimensioned to aerosolize and aerosol formulation by forming a spray when a liquid in the chamber is compressed. The chamber is compressed to administer the pharmaceutical composition of the present invention. In a specific embodiment, the chamber is a piston arrangement. Such devices are commercially available.

Alternatively, a plastic squeeze bottle with an aperture or opening dimensioned to aerosolize an aerosol formulation by forming a spray when squeezed is used. The opening is usually found in the top of the bottle, and the top is generally tapered to partially fit in the nasal passages for efficient administration of the aerosol formulation. Preferably, the nasal inhaler will provide a metered amount of the aerosol formulation, for administration of a measured dose of the drug. The compounds, when it is desirable to deliver them systemically, may be formulated for parenteral administration by injection, e.g., by bolus injection or continuous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents.

Pharmaceutical formulations for parenteral administration include aqueous solutions of the active compounds in water-soluble form. Additionally, suspensions of the active compounds may be prepared as appropriate oily injection suspensions. Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or synthetic fatty acid esters, such as ethyl oleate or triglycerides, or liposomes. Aqueous injection suspensions may contain substances which increase the viscosity of the suspension, such as sodium

carboxymethylcellulose, sorbitol, or dextran. Optionally, the suspension may also contain suitable stabilizers or agents which increase the solubility of the compounds to allow for the preparation of highly concentrated solutions.

Alternatively, the active compounds may be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use.

The compounds may also be formulated in rectal or vaginal compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides.

In addition to the formulations described above, the compounds may also be formulated as a depot preparation. Such long acting formulations may be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.

The pharmaceutical compositions also may comprise suitable solid or gel phase carriers or excipients. Examples of such carriers or excipients include but are not limited to calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin, and polymers such as polyethylene glycols.

Suitable liquid or solid pharmaceutical preparation forms are, for example, aqueous or saline solutions for inhalation, microencapsulated, encochleated, coated onto

microscopic gold particles, contained in liposomes, nebulized, aerosols, pellets for implantation into the skin, or dried onto a sharp object to be scratched into the skin. The pharmaceutical compositions also include granules, powders, tablets, coated tablets, (micro)capsules, suppositories, syrups, emulsions, suspensions, creams, drops or preparations with protracted release of active compounds, in whose preparation excipients and additives and/or auxiliaries such as disintegrants, binders, coating agents, swelling agents, lubricants, flavorings, sweeteners or solubilizers are customarily used as described above. The pharmaceutical compositions are suitable for use in a variety of drug delivery systems. For a brief review of methods for drug delivery, see Langer R, Science 249: 1527- 33 (1990), which is incorporated herein by reference.

The compounds of the invention and optionally other therapeutics may be administered per se (neat) or in the form of a pharmaceutically acceptable salt. When used in medicine the salts should be pharmaceutically acceptable, but non-pharmaceutically acceptable salts may conveniently be used to prepare pharmaceutically acceptable salts thereof. Such salts include, but are not limited to, those prepared from the following acids: hydrochloric, hydrobromic, sulphuric, nitric, phosphoric, maleic, acetic, salicylic, p-toluene sulphonic, tartaric, citric, methane sulphonic, formic, malonic, succinic, naphthalene-2- sulphonic, and benzene sulphonic. Also, such salts can be prepared as alkaline metal or alkaline earth salts, such as sodium, potassium or calcium salts of the carboxylic acid group.

Suitable buffering agents include: acetic acid and a salt (1-2% w/v); citric acid and a salt (1-3% w/v); boric acid and a salt (0.5-2.5%) w/v); and phosphoric acid and a salt (0.8- 2% w/v). Suitable preservatives include benzalkonium chloride (0.003-0.03%) w/v);

chlorobutanol (0.3-0.9% w/v); parabens (0.01-0.25% w/v) and thimerosal (0.004-0.02% w/v).

Pharmaceutical compositions of the invention contain an effective amount of a compound of the invention and optionally therapeutic agents included in a pharmaceutically acceptable carrier. The term "pharmaceutically acceptable carrier" means one or more compatible solid or liquid filler, diluents or encapsulating substances which are suitable for administration to a human or other vertebrate animal. The term "carrier" denotes an organic or inorganic ingredient, natural or synthetic, with which the active ingredient is combined to facilitate the application. The components of the pharmaceutical compositions also are capable of being commingled with the compounds of the present invention, and with each other, in a manner such that there is no interaction which would substantially impair the desired pharmaceutical efficiency. The therapeutic agent(s), including specifically but not limited to the compound of the invention, may be provided in particles. Particles as used herein means nanoparticles or microparticles (or in some instances larger particles) which can consist in whole or in part of the compound of the invention or the other therapeutic agent(s) as described herein. The particles may contain the therapeutic agent(s) in a core surrounded by a coating, including, but not limited to, an enteric coating. The therapeutic agent(s) also may be dispersed throughout the particles. The therapeutic agent(s) also may be adsorbed into the particles. The particles may be of any order release kinetics, including zero-order release, first-order release, second-order release, delayed release, sustained release, immediate release, and any combination thereof, etc. The particle may include, in addition to the therapeutic agent(s), any of those materials routinely used in the art of pharmacy and medicine, including, but not limited to, erodible, nonerodible, biodegradable, or nonbiodegradable material or combinations thereof. The particles may be microcapsules which contain the compound of the invention in a solution or in a semi-solid state. The particles may be of virtually any shape.

Both non-biodegradable and biodegradable polymeric materials can be used in the manufacture of particles for delivering the therapeutic agent(s). Such polymers may be natural or synthetic polymers. The polymer is selected based on the period of time over which release is desired. Bioadhesive polymers of particular interest include bioerodible hydrogels described in Sawhney H S et al. (1993) Macromolecules 26:581-7, the teachings of which are incorporated herein. These include polyhyaluronic acids, casein, gelatin, glutin, polyanhydrides, polyacrylic acid, alginate, chitosan, poly(methyl methacrylates), poly(ethyl methacrylates), poly(butylmethacrylate), poly(isobutyl methacrylate), poly(hexylmethacrylate), poly(isodecyl methacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate), poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutyl acrylate), and poly(octadecyl acrylate).

The therapeutic agent(s) may be contained in controlled release systems. The term "controlled release" is intended to refer to any drug-containing formulation in which the manner and profile of drug release from the formulation are controlled. This refers to immediate as well as non-immediate release formulations, with non-immediate release formulations including but not limited to sustained release and delayed release

formulations. The term "sustained release" (also referred to as "extended release") is used in its conventional sense to refer to a drug formulation that provides for gradual release of a drug over an extended period of time, and that preferably, although not necessarily, results in substantially constant blood levels of a drug over an extended time period. The term "delayed release" is used in its conventional sense to refer to a drug formulation in which there is a time delay between administration of the formulation and the release of the drug there from. "Delayed release" may or may not involve gradual release of drug over an extended period of time, and thus may or may not be "sustained release."

Use of a long-term sustained release implant may be particularly suitable for treatment of chronic conditions. "Long-term" release, as used herein, means that the implant is constructed and arranged to deliver therapeutic levels of the active ingredient for at least 7 days, and preferably 30-60 days. Long-term sustained release implants are well- known to those of ordinary skill in the art and include some of the release systems described above.

It will be understood by one of ordinary skill in the relevant arts that other suitable modifications and adaptations to the compositions and methods described herein are readily apparent from the description of the invention contained herein in view of information known to the ordinarily skilled artisan, and may be made without departing from the scope of the invention or any embodiment thereof.

EXAMPLES

Having now described the present invention in detail, the same will be more clearly understood by reference to the following examples, which are included herewith for purposes of illustration only and are not intended to be limiting of the invention.

Example 1

Oxazolidinone 1

A short three- step sequence of Fmoc protection, methyl ketal formation, and Curtius rearrangement, promoted by diphenyl phosphoryl azide, provides an intermediate isocyanate which is trapped intramolecularly to generate oxazolidinone 1 (Scheme 1). Scheme 1: Synthesis of oxazolidinone 1 and C16 AmB derivatives

AmBAU AmBMU AmBCU

This facile sequence quickly generates gram quantities of versatile intermediate 1 in a chemoselective manner from AmB. Interception of 1 with a variety of amine

nucleophiles efficiently opens the oxazolidinone while concomitantly cleaving the Fmoc protecting group. For example, exposure of 1 to ethylene diamine, followed by methyl ketal hydrolysis in acidic water generates aminoethylurea (AmBAU) 2 in 42% yield.

Similarly, utilizing methylamine accesses methyl urea (AmBMU) 3 in 36% yield from 1. Exposure of 1 to β-alanine allylester followed by allyl removal with Pd(PPh₃)₄ and thiosalicylic acid yields ethyl carboxylateurea (AmBCU) 4. This versatile synthetic strategy allows efficient access to a diverse array of AmB urea derivatives and is capable of generating large quantities of urea derivatives due to its synthetic efficiency.

Example 2

AmB Dimethyl

Oxazolidinone 1 (50.0 mg, 43.2 μιηοΐ) was dissolved in THF (2.16 mL, 0.02 M). To this solution was added dimethylamine (0.108 mL, .216 mmol, 5 equiv.). The reaction was heated to 40 °C and stirred for 12 hours, yielding a yellow precipitate. The reaction mixture was then poured into diethyl ether (30 mL), and the resulting yellow precipitate was isolated via pipetting off the diethyl ether to afford a yellow solid which was dissolved in DMSO (-66 mg/mL) and purified by prep-HPLC (Ci₈, 5-μπι, 50 x 250 mm, 25 mL/min, 95:5 to 5:95 0.3% HC0₂H (aq):MeCN over 15 minutes). After HPLC purification the desired fractions were collected in a round bottom flask. Residual formic acid was removed via azeotroping with milliQ water (10 mL) and toluene (150 mL). This process was repeated three times, yielding 2 as a yellow solid (12.7 mg, 13.2 μπιοΐ, 25% average yield per step).

Example 3

AmB Diethyl

Oxazolidinone 1 (20.0 mg, 17.3 μιηοΐ) was dissolved in THF (.864 mL, 0.02 M). To this solution was added diethylamine (8.9 μL, 86.4 μπιοΐ, 5 equiv.). The reaction was heated to 40 °C and stirred for 12 hours, yielding a yellow precipitate. The reaction mixture was then poured into diethyl ether (30 mL), and the resulting yellow precipitate was isolated via pipetting off the diethyl ether to afford a yellow solid which was dissolved in DMSO (-66 mg/mL) and purified by prep-HPLC (C_i8, 5-μιη, 50 x 250 mm, 25 mL/min, 95:5 to 5:95 0.3% HC0₂H (aq):MeCN over 15 minutes). After HPLC purification the desired fractions were collected in a round bottom flask. Residual formic acid was removed via azeotroping with milliQ water (10 mL) and toluene (50 mL). This process was repeated three times, yielding 3 as a yellow solid (8.6 mg, 8.66 μπιοΐ, 43% average yield per step).

HRMS (ESI) Calculated (C5iH₈₃N₃0i6 + H)⁺: 994.5852 Observed: 994.5852 Example 4

AmB Diisopropylurea 4)

Oxazolidinone 1 (20.0 mg, 17.3 μιηοΐ) was dissolved in THF (.864 mL, 0.02 M). To this solution was added diisopropylamine (310 μΐ_^, .691 mmol, 160 equiv.). The reaction was heated to 60 °C and stirred for 12 hours, yielding a yellow precipitate. The reaction mixture was then poured into diethyl ether (30 mL), and the resulting yellow precipitate was isolated via pipetting off the diethyl ether to afford a yellow solid which was dissolved in DMSO (-66 mg/mL) and purified by prep-HPLC (C₁₈, 5-μτη, 50 x 250 mm, 25 mL/min, 95:5 to 5:95 0.3% HC0₂H (aq):MeCN over 15 minutes). After HPLC purification the desired fractions were collected in a round bottom flask. Residual formic acid was removed via azeotroping with milliQ water (10 mL) and toluene (50 mL). This process was repeated three times, yielding 4 as a yellow solid (5.6 mg, 5.48 μπιοΐ, 28% average yield per step).

HRMS (ESI) Calculated (C₅₃H₈₈N₃Oi₆ + H)⁺: 1022.6165 Observed: 1022.6172

Example 5

AmB Piperidinourea (5)

Oxazolidinone 1 (50.0 mg, 43.2 μιηοΐ) was dissolved in THF (2.16 mL, 0.02 M). To this solution was added piperidine (21.3 [iL, .216 mmol, 5 equiv.). The reaction was heated to 40 °C and stirred for 8 hours, yielding a yellow precipitate. The reaction mixture was then poured into diethyl ether (30 mL), and the resulting yellow precipitate was isolated via pipetting off the diethyl ether to afford a yellow solid which was dissolved in DMSO (-66 mg/mL) and purified by prep-HPLC (C_i8, 5-μιη, 50 x 250 mm, 25 mL/min, 95:5 to 5:95 0.3% HC0₂H (aq):MeCN over 15 minutes). After HPLC purification the desired fractions were collected in a round bottom flask. Residual formic acid was removed via azeotroping with milliQ water (10 mL) and toluene (150 mL). This process was repeated three times, yielding 5 as a yellow solid (18.0 mg, 16.3 μπιοΐ, 36% average yield per step).

Example 6

AmB Morpholinourea 6)

Oxazolidinone 1 (20.0 mg, 17.3 μιηοΐ) was dissolved in THF (.864 mL, 0.02 M). To this solution was added morpholine (30.2 μL, .346 mmol, 20 equiv.). The reaction was heated to 40 °C and stirred for 12 hours, yielding a yellow precipitate. The reaction mixture was then poured into diethyl ether (30 mL), and the resulting yellow precipitate was isolated via pipetting off the diethyl ether to afford a yellow solid which was dissolved in DMSO (-66 mg/mL) and purified by prep-HPLC (C_i8, 5-μιη, 50 x 250 mm, 25 mL/min, 95:5 to 5:95 0.3% HC0₂H (aq):MeCN over 15 minutes). After HPLC purification the desired fractions were collected in a round bottom flask. Residual formic acid was removed via azeotroping with milliQ water (10 mL) and toluene (50 mL). This process was repeated three times, yielding 6 as a yellow solid (9.5 mg, 9.43 μπιοΐ, 47.5% average yield per step).

HRMS (ESI) Calculated (C₅iH₈iN₃0i₇ + H)⁺: 1008.5644 Observed: 1008.5668 Example 7

AmB N-methylpiperazinourea 7)

7

Oxazolidinone 1 (20.0 mg, 17.3 μιηοΐ) was dissolved in THF (.864 mL, 0.02 M). To this solution was added N-methylpiperazine (9.58 μΐ., 86.4 μπιοΐ, 5 equiv.). The reaction was heated to 40 °C and stirred for 12 hours, yielding a yellow precipitate. The reaction mixture was then poured into diethyl ether (30 mL), and the resulting yellow precipitate was isolated via pipetting off the diethyl ether to afford a yellow solid which was dissolved in DMSO (-66 mg/mL) and purified by prep-HPLC (C_i8, 5-μπι, 50 x 250 mm, 25 mL/min, 95:5 to 5:95 0.3% HC0₂H (aq):MeCN over 15 minutes). After HPLC purification the desired fractions were collected in a round bottom flask. Residual formic acid was removed via azeotroping with milliQ water (10 mL) and toluene (50 mL). This process was repeated three times, yielding 7 as a yellow solid (4.4 mg, 4.31 μπιοΐ, 22% average yield per step).

HRMS (ESI) Calculated (C₅₂H₈4N₄Oi6 + H)⁺: 1021.5691 Observed: 1021.5942

Example 8

In Vitro Assessment of Biological Activity

Each derivative described herein was tested for biological activity against both yeast and human cells to determine its therapeutic index. A broth microdilution experiment was used to determine the MIC (minimum inhibitory concentration) of each derivative against S. cerevisiae, thereby establishing the antifungal activity of each novel derivative. To test for toxicity against human cells, each compound was used in a hemolysis assay against red blood cells which determines the concentration effective to cause 90% lysis of human red blood cells (EH₉₀). Additionally, each compound is exposed to human primary renal tubule cells to determine the toxicity of each compound against kidney cells. To determine the improvement in therapeutic index for each compound the assay results where compared against the known values for AmB against the same cell lines. Results are shown in Table 2.

Table 2. Biological activity of urea derivatives

AmB 2 3 4 5 6 7

MIC (μΜ)

0.5 1 2 4 2 2 1

S. cerevisiae

EH₉₀ (μΜ)

human red 10.73 >500 >500 >500 >500 >500 >500 blood cells

Antifungal Assay

Growth Conditions for S. cerevisiae

S. cerevisiae growth was maintained with yeast peptone dextrose (YPD) growth media. The media consists of 10 g/L yeast extract, 20 g/L peptone, 20 g/L dextrose, and 20 g/L agar for solid media. The media was sterilized by autoclaving at 250° F for 30 minutes. Dextrose was subsequently added as a sterile 40% w/v solution in water (dextrose solutions were filtered). Solid media was prepared by pouring sterile media containing agar onto Corning 100 x 20 mm polystyrene plates. Liquid cultures were incubated at 30° C on a rotary shaker at 200 rpm and solid cultures were maintained at 30° C in an incubator.

Broth Microdilution Minimum Inhibitory Concentration (MIC) Assay

50 mL of YPD media was inoculated and incubated at 30° C at 200 rpm in a shaker incubator overnight. The cell suspension was then diluted with YPD to an OD₆₀o of 0.10 (~5 x 10⁵ cells/mL) as measured by a Shimadzu PharmaSpec UV-1700 UV/Vis

spectrophotometer. The solution was then diluted 10-fold with YPD, and 195 iL aliquots of the dilute cell suspension were added to sterile Falcon Microtest 96-well plates in triplicate. Compounds were prepared as 400 μΜ stock solutions and serially diluted to the following concentrations with DMSO: 320, 240, 200, 160, 120, 80, 40, 20, 10, and 5 μΜ. 5 μΐ, aliquots of each solution were added to the 96-well plate in triplicate, with each column representing a different concentration of test compound. The overall 40-fold dilution gave the following final compound concentrations: 10, 8, 6, 4, 3, 2, 1, 0.5, 0.25, and 0.125 μΜ. DMSO was added to one column as a negative control. The plate was then covered and incubated in a rotary shaker incubator at 30° C for 24 hours. The plate was then analyzed using a BioTek Synergy HI Hybrid Reader to determine the OD₆oo in each well. The MIC was determined to be the lowest concentration of compound that resulted in no visible growth of yeast. The experiments were performed in duplicate and the reported MIC represents an average of two experiments.

S. cerevisiae MIC Results

The MIC for an AmB control and each of the six derivatives was determined using a broth dilution assay in S. cerevisiae in order to test whether these derivatives retained the ability to kill fungal cells. The MIC (concentration at which no growth was observed) determined for the AmB control was 0.5 μΜ, consistent with the reported values for the MIC of AmB in S. cerevisiae. Compound 2 was found to have an MIC of 1 μΜ; 3 was found to have an MIC of 2 μΜ; 4 was found to have an MIC of 4 μΜ; 5 was found to have an MIC of 2 μΜ; 6 was found to have an MIC of 2 μΜ; and 7 was found to have an MIC of 1 μΜ (Table 2). Overall, 2 and 7 had MIC values that were the closest to the MIC of AmB (1 μΜ versus 0.5 μΜ). These two derivatives were the most effective at inhibiting growth of S. cerevisiae of all six derivatives tested. A trend in increasing MIC values could be seen with 2, 3, and 4, suggesting that steric bulk of the urea plays a role in the ability of these derivatives to effectively bind ergosterol. None of the six derivatives showed a significantly large loss in efficacy in killing yeast, demonstrating that the derivatives are still capable of binding and extracting ergosterol from yeast.

Hemolysis Assays

Erythrocyte Preparation

Whole human blood (containing sodium heparin) was purchased from

Bioreclamation LLC, stored at 4° C, and used within three days of receipt. To a 2.0 mL Eppendorf tube, 1.0 mL of whole human blood was added and centrifuged at 10,000 g for 2 minutes. The supernatant was removed and the erythrocyte pellet was washed with 1.0 mL of sterile saline and centrifuged at 10,000 g for 2 minutes. The saline wash procedure was repeated a total of three times. The erythrocyte pellet was then suspended in 1.0 mL of RBC buffer (10 mM NaH₂P0₄, 150 mM NaCl, 1 mM MgCl₂, pH 7.4) to form a stock erythrocyte suspension. Hemolysis Assay

Compounds were prepared as 12.8 mM stock solutions in DMSO and serially diluted to the following concentrations in DMSO: 7689, 5126, 2563, 2050, 1538, 1025, 769, 513, 384, 256, 205, 154, 103, 77, 51, and 26 μΜ. To a 0.2 mL PCR tube, 24 μΐ, of RBC buffer and 1 μΙ_, of compound stock solution were added, which gave final

concentrations of 500, 300, 200, 100, 80, 60, 40, 30, 20, 15, 10, 8, 6, 4, 3, 2, and 1 μΜ. The positive control used was 1 μΙ_, of DMSO in 24 μΙ_, milliQ water, and the negative control used was 1 μΐ, of DMSO in 24 μΐ, RBC buffer. To each PCR tube, 0.63 μΐ, of erythrocyte stock solution was added, and the tubes were mixed by inversion. The samples were then incubated at 37° C with an atmosphere of 95% air/5% C0₂ for 2 hours. The samples were then mixed again by inversion and centrifuged at 10,000 g for 2 minutes. 15 μΙ_, of the supernatant was removed from each sample and added to a 384-well plate. Absorbance values were determined at 540 nm using a BioTek Synergy HI Hybrid Reader. Experiments were performed in triplicate, and the reported MHC represents an average of three experiments.

Data Analysis

Percent hemolysis was determined according to the following equation:

Abs. sample— Abs. neq control \

% hemolysis = — - - — - ) X 100

\Abs. pos control— Abs. neg control/

If hemolysis occurred in the range of tested concentrations, concentration vs. percent hemolysis was plotted and fitted to 4-parameter logistic dose response fit using OriginPro 8.6. If no hemolysis occurred, concentration vs. percent hemolysis was plotted in Excel. EH₉₀ was defined as the concentration effective to cause 90% hemolysis of erythrocytes.

Hemolysis Assay Results

The EH₉₀ (concentration at which 90% of blood cells have lysed) determined for the AmB control in this assay was found to be 10.73 μΜ, which is within the percent error for the reported MHC₉₀ for AmB (8.55 μΜ). None of the six compounds tested ever reached an EH₉₀ for the range of concentrations tested, so their EH₉₀ values are shown as >500 μΜ (Table 2). Overall, all six of the secondary urea derivatives tested showed greatly reduced hemolytic capability compared to AmB, suggesting a reduction in toxicity to human cells. This reinforces the hypothesis that these urea derivatives are capable of selective sterol binding, and are not binding and extracting cholesterol from cell membranes in the way AmB does, resulting in the reduced cytotoxic phenotype observed in this assay. Example 9

In Vivo Assessment of Biological Activity

The antifungal efficacies of compounds are tested in a mouse model of disseminated candidiasis. In this experiment neutropenic mice are infected with C. albicans via the tail vein, and then 2 hours post infection the mice are treated with a single intraperitoneal injection of AmB or test agent. Then 2, 6, 12, and 24 hours post infection the mice are sacrificed, and the fungal burden present in their kidneys is quantified. INCORPORATION BY REFERENCE

All patents and published patent applications mentioned in the description above are incorporated by reference herein in their entirety.

EQUIVALENTS Having now fully described the present invention in some detail by way of illustration and example for purposes of clarity of understanding, it will be obvious to one of ordinary skill in the art that the same can be performed by modifying or changing the invention within a wide and equivalent range of conditions, formulations and other parameters without affecting the scope of the invention or any specific embodiment thereof, and that such modifications or changes are intended to be encompassed within the scope of the appended claims.

Claims

We claim:

1 A compound represented by formula (I) or a pharmaceutically acceptable salt

thereof:

(I)

wherein, independently for each occurrence:

R represents methyl, ethyl, propyl, or isopropyl;

R' represents methyl, ethyl, propyl, or isopropyl; or

R and R', taken together with the nitrogen atom to which they are attached, represent a radical of a cyclic secondary amine.

2. The compound of claim 1, wherein R and R', taken together with the nitrogen atom to which they are attached, represent a radical of a cyclic secondary amine.

3. The compound of claim 2, wherein the cyclic amine is selected from the group consisting of substituted and unsubstituted 3-7-membered nitrogen-containing rings with 0 to 2 additional ring heteroatoms independently selected from the group consisting of N, O, and S.

4. The compound of claim 2, wherein the cyclic amine is selected from the group consisting of piperidine, piperazine, 1-methylpiperazine, and morpholine.

5. The compound of claim 2, wherein the cyclic amine is selected from the group consisting of piperidine, 1-methylpiperazine, and morpholine.

6. The compound of claim 1, represented by 2:

The compound of claim 1, represented by 3:

8. The compound of claim 1, represented by 4:

The compound of claim 1, represented by 5:

The compound of claim 1, represented by 6:

12. A pharmaceutical composition, comprising a compound of any one of claims 1-11; and a pharmaceutically acceptable carrier.

13. The pharmaceutical composition of claim 12, wherein the pharmaceutical

composition is a parenteral or oral dosage form.

14. The pharmaceutical composition of claim 12, wherein the pharmaceutical

composition is a parenteral dosage form.

15. The pharmaceutical composition of claim 12, wherein the pharmaceutical

composition is an oral dosage form.

16. The pharmaceutical composition of claim 12, wherein the pharmaceutical

composition is an intravenous dosage form.

17. A method of making a compound represented by formula (I) or a pharmaceutically acceptable salt thereof:

OH NHP

(Π)

and a secondary amine, thereby forming a methyl ketal; and

combining the methyl ketal with aqueous acid, thereby forming the compound of formula (I);

wherein, independently for each occurrence:

R represents methyl, ethyl, propyl, or isopropyl;

R' represents methyl, ethyl, propyl, or isopropyl; or

R and R', taken together with the nitrogen atom to which they are attached, represent a radical of a cyclic secondary amine;

the secondary amine is represented by HN(R)R'; and

P represents a protecting group.

18. The method of claim 17, wherein the secondary amine is selected from the group consisting of dimethylamine, diethylamine, and diisopropylamine.

19. The method of claim 17, wherein the secondary amine is a cyclic secondary amine.

20. The method of claim 19, wherein the cyclic secondary amine is selected from the group consisting of substituted and unsubstituted 3-7-membered nitrogen-containing rings with 0 to 2 additional ring heteroatoms independently selected from the group consisting of N, O, and S.

21. The method of claim 19, wherein the cyclic secondary amine is selected from the group consisting of piped dine, piperazine, 1-methylpiperazine, and morpholine.

22. The method of claim 19, wherein the cyclic secondary amine is selected from the group consisting of piperidine, 1-methylpiperazine, and morpholine.

23. The method of claim 19, wherein the cyclic secondary amine is piped dine.

24. The method of claim 19, wherein the cyclic secondary amine is 1-methylpiperazine.

25. The method of claim 19, wherein the cyclic secondary amine is morpholine.

26. The method of any one of claims 17-25, wherein P is selected from the group

consisting of 9-fluorenylmethyloxycarbonyl (Fmoc), t-butyloxycarbonyl (t-Boc or Boc), /?-methoxybenzylcarbonyl, carbobenzyloxy (Cbz), acetyl, triflouroacetyl, phthalyl, benzoyl, benzyl, /?-methoxybenzyl, 3,4-dimethoxybenzyl, benzylidenyl, and ^-toluenesulfonyl (Tosyl).

27. The method of any one of claims 17-25, wherein P is Fmoc.

28. A method of inhibiting growth of a fungus, comprising contacting a fungus with an effective amount of a compound of any one of claims 1-11.

29. A method of treating a fungal infection, comprising administering to a subject in need thereof a therapeutically effective amount of a compound of any one of claims 1-11.

30. The method of claim 29, wherein the compound is administered parenterally or orally.

31. The method of claim 29, wherein the compound is administered parenterally.

32. The method of claim 29, wherein the compound is administered intravenously.

33. The method of claim 29, wherein the compound is administered orally.

34. The method of any one of claims 29-33, wherein the subject is a human.