CA2280518A1 - Hiv integrase inhibitors - Google Patents

Abstract

Natural products such as certain chaetochromins are described. These compounds are useful in the inhibition of HIV integrase, the prevention or treatment of infection by HIV and the treatment of AIDS, either as compounds, pharmaceutically acceptable salts, pharmaceutical composition ingredients, whether or not in combination with other antivirals, immunomodulators, antibiotics or vaccines. Methods of treating AIDS and methods of preventing or treating infection by HIV are also described.

Description

TITLE OF THE INVENTION
HIV INTEGRASE INHIBITORS
BACKGROUND OF THE INVENTION
A retrovirus designated human immunodeficiency virus (HIV) is the etiological agent of the complex disease that includes progressive destruction of the immune system (acquired immune deficiency syndrome; AIDS) and degeneration of the central and peripheral nervous system. This virus was previously known as LAV, HTLV-III, or ARV. A common feature of retrovirus replication is the insertion by virally-encoded integrase of proviral DNA into the host cell genome, a required step in HIV replication in human T-lymphoid cells.
Integration is believed to occur in three stages: cleavage of two nucleotides from the 3' termini of the linear proviral DNA; covalent joining of the recessed 3' OH termini of the proviral DNA at a staggered cut made at the host target site; repair synthesis by host enzymes.
Nucleotide sequencing of HIV shows the presence of a pol gene in one open reading frame [Ratner, L. et al., Nature, s~13, 227 (1985)]. Amino acid sequence homology provides evidence that the gol sequence encodes reverse transcriptase, an integrase and an HIV
protease [Toh, H. et al., EMBO J. 4 1267 (1985). Power, M. D. et al., Science, 231, 1567 (1986); Pearl, L.H. et al., Nature 329, 351 (1987)].
It is known that some antiviral compounds act as inhibitors of HIV and are effective agents in the treatment of HIV and similar diseases, e.g., azidothymidine or AZT. Applicants demonstrate that the compounds of this invention are inhibitors of HIV integrase, probably by inhibiting strand transfer and cleavage activity. The particular advantage of the present invention is specific inhibition of HIV
integrase.
Applicants have discovered that certain chaetochromins are potent inhibitors of HIV integrase. These compounds are useful for the treatment of AIDS or HIV infections.
BRIEF DESCRIPTION OF THE INVENTION

Compounds of formula I, as herein defined, are disclosed.
These compounds are useful in the inhibition of HIV integrase, the prevention of infection by HIV, the treatment of infection by HIV and in the treatment of AIDS and/or ARC, either as compounds, pharmaceutically acceptable salts or hydrates (when appropriate), pharmaceutical composition ingredients, whether or not in combination with other antivirals, anti-infectives, immunomodulators, antibiotics or vaccines. Methods of treating AIDS, methods of preventing infection by HIV, and methods of treating infection by HIV are also disclosed.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED
EMBODIMENTS
This invention is concerned with compounds of formula I, combinations thereof, or pharmaceutically acceptable salts thereof, in the inhibition of HIV integrase, the prevention or treatment of infection by HIV and in the treatment of the resulting acquired immune deficiency syndrome (AIDS). Compounds of formula I are defined as follows:

\ \ X CH3 a~
Ry0 / / O ~ CHs R O ~ ~ OwCH3 (I) wherein:
R1 is independently selected from:
(a) hydrogen, (b) C1_6 alkyl, and (c) C1-g alkylcarbonyl-at each occurrence;

-X- is selected from:
(a) a carbon-carbon single bond, and (b) an oxygen atom bound to adjacent carbon atoms; and the dotted line, a, is represents a single bond or a double bond;
or a pharmaceutically acceptable salt thereof.
In one embodiment of compounds of the present invention are compounds of structural formula (I) wherein:
R1 is independently selected from:
(a) hydrogen, (b) methyl, and (c) methylcarbonyl-at each occurrence, or a pharmaceutically acceptable salt thereof.
Compounds representing this embodiment include:
OC(O)C H3 OC(O)CH3 O
O I \ \ CH3 H3CC0 ~ ~ O~CH3 HsC~O \ \ O CH3 I O
OC(O)CH3 OC(O)CH3 Me0 C H3 Me0 CH3 OH OMe O , and Me OMe \ \ CH3 Me0 ~ ~ O~CH3 Me0 \ \ O C H3 OMe OMe O
In one subclass of compounds of the present invention are ocmpounds of structural formula (I) wherein R1 is hydrogen at each occurrence, or a pharmaceutically acceptable salt thereof.
Compounds illustrating this subclass are:

OH OH O

CHs HO CHs HO CHs CHs OH OH O
O
\ \
I , / tran CHs HO
HO O CHHs , and CHs OH OH O

HO CHs HO CHs ;is CHs OH OH O
or pharmaceutically acceptable salts thereof.
Also covered by the present invention are pharmaceutical compositions useful for inhibiting HIV integrase, comprising an effective amount of a compound of this invention. Pharmaceutical compositions useful for treating infection by HIV, or for treating AIDS
or ARC, are also encompassed by the present invention, as well as a method of inhibiting HIV integrase, and a method of treating infection by HIV, or of treating AIDS or ARC. This invention also discloses the fungal culture MF6252 (ATCC 74396), Fusa~rium sp.
_5_ OH OH O

The present invention relates to the preparation of compounds of structural formula I comprising:
(a) fermenting a culture of MF6252 (ATCC 74396), Fusarium sp. or a mutant thereof to produce a fermentation broth, (b) extracting the fermentation broth with an organic solvent, (c) isolating the compounds of structural formula I.
The compounds of structural formula I are preferably isolated by partitioning the fermentation extract between the organic solvent and water, followed by size exclusion chromatography and normal or reverse-phase chromatography.
When any variable (e.g., X, Y, etc.) occurs more than one time in any constituent or in formula I, its definition on each occurrence is independent of its definition at every other occurrence. Also, combinations of substituents and/or variables are permissible only if such combinations result in stable compounds.
The compounds of the present inventions are useful in the inhibition of HIV integrase, the prevention or treatment of infection by human immunodeficiency virus (HIV) and the treatment of consequent pathological conditions such as AIDS. Treating AIDS or preventing or treating infection by HIV is defined as including, but not limited to, treating a wide range of states of HIV infection: AIDS, ARC (AIDS
related complex), both symptomatic and asymptomatic, and actual or potential exposure to HIV. For example, the compounds of this invention are useful in treating infection by HIV after suspected past exposure to HIV by e.g., blood transfusion, exchange of body fluids, bites, accidental needle stick, or exposure to patient blood during surgery.
The compounds of this invention are useful in the preparation and execution of screening assays for antiviral compounds.
For example, the compounds of this invention are useful for isolating enzyme mutants, which are excellent screening tools for more powerful antiviral compounds. Furthermore, the compounds of this invention are useful in establishing or determining the binding site of other antivirals to HIV integrase, e.g., by competitive inhibition. Thus, the compounds of this invention are commercial products to be sold for these purposes.

Applicants have discovered that certain chaetochromins, recovered from a fungal culture of MF6252 (ATCC 74396), identified as Fusarium sp. (Ascomycotina, Hypocreales), are useful for inhibiting HIV integrase. The compounds of formula (I) are prepared by an aerobic fermentation procedure employing a novel fungal culture MF6252 (ATCC 74396), identified as Fusccrium sp., or a mutant thereof.
A mutant refers to an organism in which some gene on the genome is modified, leaving the gene or genes responsible for the organism's ability to produce the compounds of formula (I) in recoverable amounts functional and heritable.
ATCC Deuosit of MF6252 (ATCC 74396) identified as Fusarium sn.
Before the U.S. filing date of the present application, a sample of MF6252 (ATCC 74396), Fusczrium sp., had been deposited at the American Type Culture Collection (ATCC), 12301 Parklawn Drive, Rockville, MD 20852. The culture access designation is 74396. This deposit will be maintained in the ATCC for at least 30 years and will be made available to the public upon the grant of a patent disclosing it. It should be understood that the availability of a deposit does not constitute a license to practice the subject invention in derogation of patent rights granted by government action.
Characteristics of MF6252 (ATCC 74396) Fusarium sn.
Isolated from forest leaf litter, Te Anau, South Island of New Zealand.
In agar culture MF6252 = ATCC 74396 exhibits the following characteristics. Observations of micromorphology were made on 1 week-old colonies grown on SNA unless stated otherwise.
Colonies on SNA (Synthetischer Nahrstoffarmer agar;
Gerlach, W. and Nirenberg, H. 1982. The genus Fusarium - a pictorial atlas. Milleilungen aus der Biologische Bundesanstalt fiir Land- and Forstwirtschaft, Berlin-Dahlem 209: 1-406) at 25°C, 12 hr photoperiod attaining 25-26 mm after 7 days, translucent, faintly zonate, mycelium most appressed or submerged, with some scant moist conidial pustules surrounding inoculation point _7_ Colonies on oatmeal agar (Difco Laboratories) at 25°C, 12 hr photoperiod attaining 24-25 mm after 7 days, developing pronounced moist radial hyphal strands, floccose to plumose, with margin even, submerged, with aerial mycelium white to pale peach-colored, Pale Ochraceous-Buff, Light Buff (capitalized color names from Ridgway, R.
1912. Color Standards and Nomenclature, Washington, D.C.),basal mycelium yellowish green, Primrose Yellow to near Olive-Yellow. After one month, strongly radially piumose, zone, white to yellowish green.
No growth on oatmeal agar at 37°C.
Colonies on potato dextrose agar (Difco Laboratories) at 25°C, 12 hr photoperiod, attaining 19-20 mm after 7 days, with wide, submerged or moist margin, quickly developing strong radial, semi-erect hyphal strands, dull peach colored to yellowish green, Light Buff, Napthalene Yellow, buff to dull olive, Cream-Buff to near Yellowish Olive, in reverse.
Conidiophores, conidiogenous cells and conidia are of two different states; an Acremonium-like microconidial state which is the dominant form on SNA; and a macroconidial state which on SNA is restricted to pinnotes in the area immediately surrounding the inoculation point, on other media, e.g. potato-dextrose agar, the macroconidial form is produced throughout the colony.
Microconidial state: Microconidiophores 25-70 ~m long x 2.5-4 N,m wide at the base, septate at the base, rarely 2- or 3-septate, mostly unbranched, tapered upward, straight to slightly geniculate, scattered to densely clustered on both the surface and aerial hyphae, terminating in a cylidrical to flared collarette, with slight periclinal thickening evident on some conidiogenesis cells, enteroblastic, phialidic.
Microcondia for the most part distinct from macroconidia, 3.5-6 x 2-3 Vim, narrowly ellipsoidal to allantoid.
Macroconidial state: Macroconidiophores aggregated in pinnotes, consisting of penicillately branched fascicles of conidiogenous cells. Conidiogenous cells cylindrical or tapered apically, without collarettes, sometimes with slight periclinal thickenings at conidiogenous loci, with individual conidiogenous cells up to 35 ~tm long.
_g_ Macroconidia 10-50 N,m x 3.5-5 ~,m 1-6 septate, predominantly 3-septate, fusiform curved, with apical cell rounded, with slightly pedicellate foot cell, often the apical or subapical cells more curved than the more proximal cells.
Chlamydospores and sclerotia not in observed in PDA or OA
cultures incubated up to 5 weeks.
This fungus is assigned the anamorph genus Fusarium because it produces moist, fusoid, curved, septate conidia with a pedicellate foot cell from phialidic conidiogenous cells. This isolate possibly belongs in the Section Mcxrtiella of Fusarium (as defined by C.
Booth. 1971. The genus Fusarium. Commonwealth Mycological Institute, Kew, U.K., pg. 44), due to its abundant Acremonium-like conidial state, penicillate macrocroconidial state, macroconidia with blunt rounded apices, pale to yellow or greenish yellow pigments, and moderate growth rate. The absence of chlamydospores has been noted in some species of the section Martiella e.g. F. illuduns and the Fusarium state of Nectrio borneensis (Samuels, G. J., Y. Doi, and C. T. Rogerson.
1990. Memoirs of the New York Botanical Garden 59: 47-48).
In general, MF6252 (ATCC 74396), identified as Fusarium sp. is cultured on a solid medium, or in an aqueous nutrient medium containing sources of assimilable carbon and nitrogen. For example, the cultures can be grown under submerged aerobic conditions (e.g., shaking culture, submerged culture, etc. ) The aqueous medium is preferably maintained at a pH of about 6-8 at the initiation and termination (harvest) of the fermentation process. The desired pH may be maintained by the use of a buffer such as morpholinoethane-sulfonic acid (MES), morpholinopropanesulfonic acid (MOPS), and the like, or by choice of nutrient materials which inherently possess buffering properties.
The preferred source of carbon in the nutrient medium are carbohydrates such as glucose, xylose, galactose, glycerin, starch, sucrose, dextrin, and the like. Other cources which may be included are maltose, rhamnose, raffinose, arabinose, mannose, sodium succinate, and the like.
-g_ The preferred sources of nitrogen are yeast extract, meat extract, peptone, gluten meal, cottonseed meal, soybean meal and other vegetable meals (partially or totally defatted), casein hydrolysates, soybean hydrolysates, and yeast hydrolysates, corn steep liquor, dried yeast, wheat germ, feather meal, peanut powder, distiller's solubles, etc., as well as inorganic and organic nitrogen compounds such as ammonium salts (e.g., ammonium nitrate, ammonium sulfate, ammonium phosphate, etc.), urea, amino acids, and the like.
The carbon and nitrogen sources, though advantageously employed in combination, need not be used in their pure form, because less pure materials which contain traces of growth factors and considerable quantities of mineral nutrients, are also suitable for use.
When desired, there may be added to the medium mineral salts such as sodium or calcium carbonate, sodium or potassium phosphate, sodium or potassium chloride, sodium or potassium iodide, magnesium salts, copper salts, cobalt salts, and the like. If necessary, especially when the culture medium foams seriously, a defoaming agent, such as liquid paraffin, fatty oil, plant oil, mineral oil or silicone may be added.
As to the conditions for the production of cells in massive amounts, submerged aerobic cultural conditions is one method of culturing the cells. For the production in small amounts, a shaking or surface culture in a flask or bottle is employed. Furthermore, when the growth is carried out in large tanks, it is preferable to use the vegetative forms of the organism for inoculation in the production tanks in order to avoid growth lag in the process of production. Accordingly, it is desirable first to produce a vegetative inoculum of the organism by inoculating a relatively small quantity of culture medium with spores or mycelia of the organism produced in a "slant" and culturing said inoculated medium, also called the "seed medium", and then to transfer the cultured vegetative inoculum aseptically to large tanks. The fermentation medium, in which the inoculum is produced, is generally autoclaved to sterilize the medium prior to inoculation. The pH of the medium is generally adjusted to about 6-7 to the autoclaving step.
Agitation and aeration of the culture mixture may be accomplished in a variety of ways. Agitation may be provided by a propeller or similar mechanical agitation equipment, by revolving or shaking the fermentor, by various pumping equipment, or by the passage of sterile air through the medium. Aeration may be effected by passing sterile air through the fermentation mixture.
The fermentation is usually conducted at a temperature between about 20°C and 30°C, preferably 22-25°C, for a period of about 14-21 days, which may be varied according to fermentation conditions and scales.
Preferred culturing/production media for carrying out the fermentation include the media as set forth in the Examples.
After growth is completed, the cells are harvested by conventional methods, e.g., centrifugation and filtration, and then extracted with the appropriate solvent, e.g., methylethylketone.
The product of the present invention can be recovered from the culture medium by conventional means which are commonly used for the recovery of other known substances. The substances produced may be found in either or both the cultured mycelium and broth filtrate, and accordingly can be isolated and purified from the mycelium and the filtrate, which are obtained by filtering or centrifuging the cultured broth, by a conventional method such as concentration under reduced pressure, lyophilization, extraction with a conventional solvent, such as methylene chloride or methanol and the like, pH adjustment, treatment with a conventional resin (e.g., anion or cation exchange resin, non-ionic adsorption resin, etc.), treatment with a conventional adsorbent (e.g., activated charcoal, silicic acid, silica gel, cellulose, alumina, etc.), crystallization, recrystallization, and the like. A preferred method is extraction of cultured whole broth with methylethylketone, followed by filtration of the extract through filtering aid such as diatomaceous earth. The methylethylketone layer of the filtrate was separated and concentrated to dryness initially by evaporating under reduced pressure followed by lyophilization. The compounds were finally isolated either by solvent partitioning and crystallization or by preparative HPLC on reversed phase systems.
Compounds of formula (I) may be isolated from the aerobic fermentation of a culture of MF6252 (ATCC 74396), F'usaraum sp.. A

culture of MF6252 (ATCC 74396) is defined as substantially free of its natural soil contaminants and capable of forming compounds of structural formula (I) in recoverable amounts. The culture employed in the present invention should be free from viable contaminating microorganisms deleterious to the production of the compound of structural formula (I). A biologically pure culture of MF6252 (ATCC 74396) may also be employed.
The pharmaceutically acceptable salts of the compounds of this invention include those formed from cations such as sodium, potassium, aluminum, calcium, lithium, magnesium, zinc, and from bases such as ammonia, ethylenediamine, N-methyl-glutamine, lysine, arginine, ornithine, choline, N,N'-dibenzylethylenediamine, chloroprocaine, diethanolamine, procaine, N-benzylphenethylamine, diethylamine, piperazine, tris(hydroxymethyl)aminomethane, and tetramethylammonium hydroxide. These salts may be prepared by standard procedures, e.g. by reacting the free acid with a suitable organic or inorganic base.
For these purposes, the compounds of the present invention may be administered orally, parenterally (including subcutaneous injections, intravenous, intramuscular, intrasternal injection or infusion techniques), by inhalation spray, or rectaliy, in dosage unit formulations containing conventional non-toxic pharmaceutically-acceptable carriers, adjuvants and vehicles.
The terms "administration of and or "administering a"
compound should be understood to mean providing a compound of the invention or a prodrug of a compound of the invention to the individual in need of treatment.
Thus, in accordance with the present invention there is further provided a method of treating and a pharmaceutical composition for treating HIV infection and AIDS. The treatment involves administering to a patient in need of such treatment a pharmaceutical composition comprising a pharmaceutical carrier and a therapeutically-effective amount of a compound of the present invention.
As used herein, the term "composition" is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results directly, or indirectly, from combination of the specified ingredients in the specified amounts.
These pharmaceutical compositions may be in the form of orally-administrable suspensions or tablets, nasal sprays, sterile injectible preparations, for example, as sterile injectible aqueous or oleagenous suspensions or suppositories.
When administered orally as a suspension, these compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may contain microcrystalline cellulose for imparting bulk, alginic acid or sodium alginate as a suspending agent, methylcellulose as a viscosity enhancer, and sweeteners/flavoring agents known in the art. As immediate release tablets, these compositions may contain microcrystalline cellulose, dicalcium phosphate, starch, magnesium stearate and lactose and/or other excipients, binders, extenders, disintegrants, diluents and lubricants known in the art.
When administered by nasal aerosol or inhalation, these compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other solubilizing or dispersing agents known in the art.
The injectible solutions or suspensions may be formulated according to known art, using suitable non-toxic, parenterally-acceptable diluents or solvents, such as mannitol, 1,3-butanediol, water, Ringer's solution or isotonic sodium chloride solution, or suitable dispersing or wetting and suspending agents, such as sterile, bland, fixed oils, including synthetic mono- or diglycerides, and fatty acids, including oleic acid.
When rectally administered in the form of suppositories, these compositions may be prepared by mixing the drug with a suitable non-initiating excipient, such as cocoa butter, synthetic glyceride esters of polyethylene glycols, which are solid at ordinary temperatures, but liquefy and/or dissolve in the rectal cavity to release the drug.

The compounds of this invention can be administered orally to humans in a dosage range of 1 to 1000 mg/kg body weight in divided doses. One preferred dosage range is 0.1 to 200 mg/kg body weight orally in divided doses. Another preferred dosage range is 0.5 to 100 mg/kg body weight orally in divided doses. For oral administration, the compositions are preferably provided in the form of tablets containing 1.0 to 1000 milligrams of the active ingredient, particularly 1.0, 5.0, 10.0, 15Ø 20.0, 25.0, 50.0, 75.0, 100.0, 150.0, 200.0, 250.0, 300.0, 400.0, 500.0, 600.0, 750.0, 800.0, 900.0, and 1000.0 milligrams of the active ingredient for the symptomatic adjustment of the dosage to the patient to be treated.
It will be understood, however, that the specific dose level and frequency of dosage for any particular patient may be varied and will depend upon 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 host undergoing therapy.
The present invention is also directed to combinations of the HIV integrase inhibitor compounds with one or more agents useful in the treatment of AIDS. For example, the compounds of this invention may be effectively administered, whether at periods of pre-exposure and/or post-exposure, in combination with effective amounts of the AIDS
antivirals, imunomodulators, antiinfectives, or vaccines, such as those in the following table.

ANTIVIRALS
Drug Name Manufacturer Indication AL-721 Ethigen ARC, PGL
{Los Angeles, CA) HIV positive, AIDS
Recombinant Human Triton Biosciences AIDS, Kaposi's Interferon Beta (Almeda, CA) sarcoma, ARC
Acemannan Carrington Labs ARC
(Irving, TX) (See also immunomodulators ) Cytovene Syntex sight Ganciclovir (Palo Alto, CA) threatening CMV
peripheral CMV
retinitis d4T Bristol-Myers AIDS, ARC

Didehydrodeoxy- (New York, NY) thymidine ddI Bristol-Myers AIDS, ARC

Dideoxyinosine (New York, NY) EL10 Elan Corp, PLC HIV infection (Gainesville, GA) (See also immunomodulators) Trisodium Astra Pharm. CMV retinitis, HIV

Phosphonoformate Products, Inc infection, other CMV

(Westborough, MA) infections Dideoxycytidine; Hoffman-La Roche AIDS, ARC
ddC (Nutley, NJ) Novapren Novaferon Labs, Inc. HIV inhibitor (Akron, OH) Diapren, Inc.
(Roseville, MN, marketer) Peptide T Peninsula Labs AIDS
Octapeptide (Belmont, CA) Sequence Zidovudine; AZT Burroughs Wellcome AIDS, adv, ARC
(Rsch. Triangle Park, pediatric AIDS, NC) Kaposi's sarcoma, asymptomatic HIV
infection, less severe HIV disease, neurological involvement, in combination with other therapies.
Ansamycin Adria Laboratories ARC
LM 427 (Dublin, OH) Erbamont (Stamford, CT) Dextran Sulfate Ueno Fine Chem. AIDS, ARC, HIV
Ind. Ltd. positive asymptomatic (Osaka, Japan) Virazole Viratek/ICN asymptomatic HIV
Ribavirin (Costa Mesa, CA) positive, LAS, ARC
Alpha Interferon Burroughs Wellcome Kaposi's sarcoma, (Rsch. Triangle HIV in combination Park, NC) w/Retrovir Acyclovir Burroughs Wellcome AIDS, ARC, asymptomatic HIV
positive, in combination with AZT.
Antibody which Advanced Biotherapy AIDS, ARC
neutralizes pH Concepts labile alpha aberrant (Rockville, MD) Interferon in an immuno-adsorption column Indinavir Merck (Rahway, NJ) AIDS, ARC, asymptomatic HIV
positive, also in combination with AZT.
Nevirapine Boeheringer AIDS, ARC
Ingleheim (protease inhibitor) Delaviridine Pharmacia-Upjohn AIDS, ARC
(protease inhibitor) Ritonavir Abbott AIDS, ARC
(protease inhibitor) Saquinavir Hoffmann- AIDS, ARC
LaRoche (protease inhibitor) Nelfinavir Agouron AIDS, ARC
Pharmaceuticals (protease inhibitor) 141 W94 Glaxo-Wellcome AIDS, ARC
(protease inhibitor) DMP-266 DuPont-Merck AIDS, ARC
Pharmaceuticals (non-nucleoside reverse transcriptase inhibitor) WO 98/34932 PCT/(TS98/02292 IMMUNO-MODULATORS
Drug Name Manufacturer Indi-ration AS-101 Wyeth-Ayerst Labs. AIDS
(Philadelphia, PA) Bropirimine Upjohn advanced AIDS
(Kalamazoo, MI) Acemannan Carrington Labs, Inc. AIDS, ARC (See also (Irving, TX) anti-virals) CL246,738 American Cyanamid AIDS, Kaposi's (Pearl River, NY) sarcoma Lederle Labs (Wayne, NJ) EL10 Elan Corp, PLC HIV infection (Gainesville, GA) (See also anti-virals) Gamma Interferon Genentech ARC, in combination (S. San Francisco, CA) w/TNF (tumor necrosis factor) Granulocyte Genetics Institute AIDS
Macrophage Colony (Cambridge, MA) Stimulating Sandoz Factor (East Hanover, NJ) Granulocyte Hoeschst-Roussel AIDS
Macrophage Colony (Sommerville, NJ) Stimulating Immunex Factor (Seattle, WA) _ 19_ Granulocyte Schering-Plough AIDS

Macrophage Colony (Madison, NJ) AIDS, in combination Stimulating Factor w/AZT

HIV Core Particle Rorer seropositive HIV

Immunostimulant (Ft. Washington, PA) IL-2 Cetus AIDS, in combination Interleukin-2 (Emeryville, CA) w/AZT

IL-2 Hoffman-La Roche AIDS, ARC, HIV, in Interleukin-2 (Nutley, NJ) combination w/AZT

Immunex Immune Globulin Cutter Biological pediatric AIDS, in Intravenous (Berkeley, CA) combination w/AZT

(human) IMREG-1 Imreg AIDS, Kaposi's (New Orleans, LA) sarcoma, ARC, PGL

IMREG-2 Imreg AIDS, Kaposi's (New Orleans, LA) sarcoma, ARC, PGL

Imuthiol Diethyl Merieux Institute AIDS, ARC

Dithio Carbamate (Miami, FL) Alpha-2 Schering Plough Kaposi's sarcoma Interferon (Madison, NJ) w/AZT: AIDS

Methionine- TNI Pharmaceutical AIDS, ARC

Enkephalin (Chicago, IL) MTP-PE Ciba-Geigy Corp. Kaposi's sarcoma Muramyl-Tripeptide (Summit, NJ) Granulocyte Amgen AIDS, in combination Colony Stimulating (Thousand Oaks, CA) w/AZT
Factor rCD4 Genentech AIDS, ARC
Recombinant (S. San Francisco,CA) Soluble Human CD4 rCD4-IgG AIDS, ARC
hybrids Recombinant Biogen AIDS, ARC
Soluble Human CD4 (Cambridge, MA) Interferon Hoffman-La Roche Kaposi's sarcoma Alfa 2a (Nutley, NJ) AIDS, ARC, in combination w/AZT
SK&F106528 Smith, Kline & French HIV infection Soluble T4 Laboratories (Philadelphia, PA) Thymopentin Immunobiology HIV infection Research Institute (Annandale, NJ) Tumor Necrosis Genentech ARC, in combination Factor; TNF (S. San Francisco, CA) w/gamma Interferon ANTI-INFECTIVF

Drug Name Manufacturer Indication Clindamycin with Upjohn pCp Primaquine (Kalamazoo, MI) Fluconazole Pfizer cryptococcal (New York, NY) meningitis, candidiasis Pastille Squibb Corp. prevention of Nystatin Pastille {Princeton, NJ) oral candidiasis Ornidyl Merrell Dow PCP

Eflornithine (Cincinnati, OH) Pentamidine LyphoMed PCP treatment Isethionate (IM {Rosemont, IL) & 1V) Trimethoprim antibacterial Trimethoprim/sulfa antibacterial Piritrexim Burroughs Wellcome PCP treatment (Rsch. Triangle Park, NC) Pentamidine Fisons Corporation PCP prophylaxis isethionate for (Bedford, MA) inhalation Spiramycin Rhone-Poulenc cryptosporidial Pharmaceuticals diarrhea (Princeton, NJ) Intraconazole- Janssen Pharm. histoplasmosis;
851211 (Piscataway, NJ) cryptococcal meningitis Trimetrexate Warner-Lambert PCP
OTHER
Drug Name Manufacturer Indication Recombinant Human Ortho Pharm. Corp. severe anemia Erythropoietin (Raritan, NJ) assoc. with AZT

therapy Megestrol Acetate Bristol-Myers treatment of (New York, NY) anorexia assoc.

wlAIDS

Total Enteral Norwich Eaton diarrhea and Nutrition Pharmaceuticals malabsorption (Norwich, NY) related to AIDS

It will be understood that the scope of combinations of the compounds of this invention with AIDS antivirals, immunomodulators, anti-infectives or vaccines is not limited to the list in the above Table, but includes in principle any combination with any pharmaceutical composition useful for the treatment of AIDS.

Indinavir is an inhibitor of HIV protease and is the sulfate salt of N-(2(R)-hydroxy-1(S)-indanyl)-2(R)-phenylmethyl-4-(S)-hydroxy-5-( 1-(4-(3-pyridyl-methyl)-2(S)-N'-(t-butylcarboxamido)-piperazinyl))-pentaneamide ethanolate, and is synthesized according to U.S. 5,413,999.
Indinavir is generally administered at a dosage of 800 mg, three times a day.

Fermentation A . Media:
Seed medium contained the following in g/L: corn steep liquor, 5 g; tomato paste, 40; oat flour, 10; glucose, 10; agar, 4;
FeS04 ~ 7H20, 0.01; MnS04 ~ 4H20, 0.01; CuCl2 ~ 2H20, 0.00025; CaCl2, 0.001; H3B03, 0.00056; (NH4)gMo7024 ~ 4H20, 0.00019; ZnS04 ~ 7H20, 0.002. The pH was adjusted to 6.8.
Production media contained the following in grams per liter: sucrose, 80; yellow corn meal, 50; yeast extract, 1.
B. Inoculum Preparation:
Frozen vegetative mycelia (FVM) were prepared by inoculating 50 mL of seed medium in a 250 mL flask and incubating at 25C°, 85% relative humidity and at 200 rpm for 3-5 days. Aliquots of the culture were frozen and used as a source of inoculum for future experiments.
C . Seed Culture:
To 50 mL of seed media in a 250 mL flask, 2.0 mL of FVM
was added as inoculum and the flasks were incubated at 25°C, 8%
relative humidity and at 200 rpm for 2-3 days.
D. Production Culture and Extraction:
To 50 mL of production media in a 250 mL flask, 1 mL of seed culture was added as inoculum and the flasks were incubated at 25°C, 85% relative humidity and at 200 rpm for 21 days. Each flask was then extracted with 50 mL of methyl ethyl ketone and the solids were discarded.
F~~AMPLE 2 Isolation and Characterizat»n~ f ompounds A and B
I First Isolation HO CH3 HO Hs HO CH3 HO Hs Compound A Compound B
Five mL of fermentation broth of culture MF6252 (ATCC
74396) was extracted with 50 mL of methyl ethyl ketone to give yellowish green extract. The extract was concentrated under reduced pressure to remove most of the methyl ethyl ketone followed by lyophilization to give 40 mg of viscous greenish gum. This gummy material was chromatographed over a SEPHADEX LH-20 column (200 mL). The material was charged in methanol-methylene chloride (5 mL, 1:1 ) and the column was eluted with methanol. The HIV-integrase activity eluted in a broad zone and the fractions that showed activity against HIV-integrase were combined and chromatographed on a ZORBAX RX C-8 (22 x 250 mm) reverse phase column. The compounds were eluted from the column with a 60 minutes linear gradient of 50 to 90% aqueous acetonitrile containing 0.1°~o trifluoroacetic acid at a flow rate of 10 mL
per minute. The elution of the column was monitored by a in-line ultraviolet detection at 250 nm. Fractions eluting at 27 and 28 minutes were concentrated and subsequently lyophilized to give compound A and compound B, respectively, as yellow powders.
The purity of these compounds was evaluated by an analytical HPLC using ZORBAX RX C-8 (4.6 x 250 mm) column eluting at a flow rate of 1 mL per minute with 65% aqueous acetonitrile (+0.1°l0 TFA). compound A eluted at a retention time of 8.1 minute and compound B eluted at a retention time of 9.0 minutes. These compounds are members of chaetochromin/ ustilaginoidin family. One set of the methyl groups in each of these compounds is cis and the other set is trczns. Atropisomers were assigned based on the comparison of the optical rotation values. Chaetochromin B ([a]D +524, ref. Koyama &
Natori Chem. Pharm. Bull. vol 35, pp 578-584, 1987) has same gross structure as A ([a]D +827) and B ([a]D -188) except for stereo-chemistry.
Both of these compounds are nonsymmetrical dimers.
II. Second Isolation OH OH O
\ \
/ / CHs Hs HO ~ ~ O
HO \ ~ O CH3 H Hs Hs ~~ ~s C D
A 1.2 L regrowth of MF6252 (ATCC 74396) was extracted with methyl ethyl ketone to give an 850 mL extract that was concentrated as described above in part I, First Isolation. The dark semi solid thus obtained was dissolved in methanol-acetone (4:1, 250 mL) and was filtered. The filtrate was similarly chromatographed over a SEPHADEX
LH-20 column and column was eluted with methanol. The fractions OH OH O

WO 98/34932 PCT/fJS98/02292 were evaluated by TLC (silica gel, Methylene chloride-Methanol, 92/8 +0.1 % AcOH). The fraction eluting from 2500 mL to 3000 mL of elution volume of methanol were combined and concentrated to give fraction A;
fractions from 3001 to 4100 mL elution volume of methanol gave fraction B and 4001 mL to 6000 mL gave fraction C.
A 75 mg portion of fraction A was dissolved in 0.5 mL
acetonitrile and was chromatographed over a ZORBAX RX C-8 (22 x 250 mm) reverse phase column and eluted with a 60 minutes gradient of 40 to 60% aqueous acetonitrile containing 0.1% TFA at a flow rate of 10 mL
per minute. The elution was detected by 210 nm in-line ultra violet light.
The fractions eluting between 34 to 38 minutes were combined, concentrated under reduced pressure, and lyophilized to give compound C as a yellow powder.
Fraction B ( 1.0 g) was chromatographed on a silica gel column (3 x 20 cm). The column was packed in and washed with methylene chloride and the material was loaded in a 1:1 mixture of methylene chloride - acetone. Elution of the column with 4% methanol in methylene chloride containing 0.1 °~o acetic acid and concentration of the fractions gave compound B as yellow powder.
Fraction C (50 mg) was dissolved in 0.5 mL acetonitrile and was chromatographed on a similar ZORBAX RX C-8 column. Elution of the column at 10 mL per minute with a 80 minute step gradient of aqueous acetonitrile containing 0.1% TFA. The gradient was as follows:
50% aqueous acetonitrile for 10 minute, 50 to 70% (10.01 to 70 minute) and 70 to 100% (70.01 to 80 minute). The fractions eluting between 46-47 minutes were combined, concentrated and lyophilized to give compound D as a yellow powder. Compound C has 2,3-trc~ns and 2',3'-cis stereochemistry. Compound D has a 2,3-Cis stereochemistry.

Physical and Spectral Properties:
I. Compound A:
Mass spectra: HREIMS (m/z): 546.1505 (M+, calcd. for C30H26410: 546.1525).
Specific rotation: [a]25D = +827 (c, 0.13, MeOH) NMR Spectra: See Tables 1 and 2.
II. Comtoound B:
Mass spectra: HREIMS (m/z): 546.1501 (M+, calcd. for C3pH26010:
546.1525).
Specific rotation: [a]25D = -188 (c, 0.13, MeOH) NMR Spectra : See Tables 1 and 2.
III. Compound C:
Mass spectra: HREIMS (mlz): 562.1458 (M+, calcd. for C30H26011: 562.1475).
NMR Spectra: See Table 3.
IV. Compound D:
Mass spectra: HREIMS (m/z): 544.1365 (M+, calcd. for C3pH24O10:
544.1369).
NMR Spectra : See Table 2.
~C NMR andlH NMR
All of the NMR spectra were recorded on a Varian Unity 400 or a Varian 300 MHz spectrometers operating at a field strength of 400 MHz and 300 MHz for proton NMR, 100 and 75 MHz for carbon NMR
respectively. The data are summarized in following Tables. The coupling constant, J, is expressed in Hz.
Table 1: 13C NMR Assignment of Compound A and Compound B in CDC13 at 75 MHz.

7 5a 4a HO ~ a CH3 O~ ~CH3 H; 0 Carbon # Compound A (8C) Compound B (8C) 2,2' 78.4, 75.6 78.4, 75.6 3,3' 46.1, 44.4 46.2, 44.4 4,4' 202.3, 200.7 202.3, 200.7 4a, 4a' 101.5, 101.4 101.5, 101.4 5, 5' 165.6, 164.7 165.6, 164.7 5a, 5a' 105.6, 105.1 105.6, 105.0 6, 6' 158.5, 158.3 158.6, 158.2 7, T 100.1, 99.8 100.1, 99.9 8, 8' 161.1, 159.5 161.1, 159.7 9, 9' 102.1, 102.0 102.4, 102.0 9a, 9a' 142.6, 141.3 142.6, 141.2 10, 10' 99.0, 99.0 99.1, 99.1 10a, l0a' 156.1, 155.5 156.2, 155.4 2-CH3, 2'-CH319.7, 16.6 19.7, 16.5 3-CH3, 3'-CH310.2, 9.7 10.0, 9.7 Table 2: 1H NMR Assignment of Compound A; Compound B and Compound D in CDC13 Proton Compound A Compound B Compound D
#

8H (J values 8H (J values in 8H (J values in Hz) Hz) in Hz) in CDC13 in CDC13 in CD3CN

(300 MHz) (300 MHz) (400 MHz) 2,2' 4.17,dq, J = 4.14,dq, J = 11.1,4.65,dq, J =
10.8, 3.0, 6.3 6.3 6.4 4.64, dq, J = 4.62, dq, J =
3.0, 6.6 3.0, 6.6 3,3' 2.75, dq, J = 2.72, dq, J = 2.80, dq, J =
3.0, 7.0 3.0, 7.5 2.66, dq,J = 2.66,dq, J = 6.9,2.4,7.3 6.9, 10.8 10.8 7, 7' 6.55, s 6.56, s 6.54, s 6.57, s 6.56, s 6.48, s 10, 10' 6.15, s 6.13, s 6.42, s 6.75, s 6.72, s 6.68, s 2-CH3 1.44, d, J = 1.43, d, J = 6.3 1.37, d, J =
6.6 Hz 6.8 2'-CH3 1.44, d, J = 1.43, d, J = 6.3 2.29, s 6.6 Hz 3-CH3 1.26, d, J = 1.26, d, J = 7.2 1.26, d, J =
7.5 Hz 7.2 3'-CH3 1.25, d, J = 1.23, d, J = 6.9 1.96, s 7.2 Hz 5-OH, 5'-O15.53, s; 15.39,15.48, s; 15.36, 16.64, s; 15.64, s s s 6-OH, 6'-O9.93, s; 9.77, 9.93, s; 9.76, 9.94, s; 9.72, s s s 8-OH, 8'-O5.49, brs; 5.28,5.69, brs; 5.29, 5.69, brs; 5.29, brs brs brs Table 3: I3H and 13C NMR Assignment of Compound Cin a mixture of CDCl3 and CD3CN at 400 MHz at 25 °C.
OH OH
O O
4b 4 3 CHg t O CHa O~~CH3 ~H'' Carbon gC gH 8H

(1:1 CDC13/CD3CN) (4:1 CDC13/CD3CN) 2 82.6 4.33, m 4.15, dq, J = 10.4 ' 6.4 2 74.7 4.62, dq, J = 3.6, , 6.4 4.42, d , J = 3.6, 6.8 3 ~ 41.2 2.86, m 2.67, dq, J = 10.8 3 43.1 2.77, dq, J = 3.6, , 6.8 .
2.55, d , J = 3.26, 6.0 4 170.9 ____ -___ 4' 201.3 ____ ____ 4a 126.6* ---- ____ 4a' 100.2 ____ ____ 142.4 ____ ____ 5' 165.0 ____ ____ 5a 107.6 ---- _-__ 5a' 103.9 ____ -__-6 I54.5 _-__ ____ 6' 157.2 ____ ____ 7 100.4 6.53, s 6.37, s 7' 100.9 6.62, s 6.45, s 8 153.3 _-__ ____ 8' 159.4 ---- ____ 102.6 ---- -___ 9' 104.4 ____ ____ 9a 132.6* ____ ____ 9a' 141.3 ---- ___-108.6 6.40, s 6.24, s 10' 99.8 6.48, s 6.32, s 10a 142.9 ____ ____ l0a' 154.2 ---- -__-2-CH3 16.5 1.15, d, J = 6.0 0.99, d, J = 6.4 2'-CH3 15.3 1.36, d, J = 6.4 1.19, d, J = 6.8 3-CH3 12.1 1.06, d, J = 6.8 0.91, d, J = 6.4 3'-CH3 8.43 1.18, d, J = 7.2 1.02, d, J = 7.2 5-OH ____ 5'-OH ---- 15.6, s 15.5, s 6-OH ____ 6'-OH ---- 9.7, s 9.6, s 8-OH ____ g~_OH ____ Acetvlation of compound B:

HO CH3 ~ Ac0 CH3 HO CH3 Ac0 CH3 OH OH O OAc OAc O
Compound B Compound E
To a solution of compound B (20 mg) in pyridine (0.5 mL) was added 0.5 mL acetic anhydride. The solution was stirred at room temperature overnight. Methanol was added to the reaction mixture and was concentrated under reduced pressure to dryness. The product was purified by preparative silica gel TLC (hexane-EtOAc, 3:7) and the major yellow band was eluted with 2% methanol in EtOAc to give hexaacetate (compound E) of compound B as a pale powder. HREIMS
(m/z): 798 (15%, M+), 1NMR (b in CDC13 at 60 °C): 1.16 (3H, d, J = 6.8 Hz, CH3), 1.18 (3H, d, J = 6.8 Hz, CH3), 1.41 (3H, d, J = 6.8 Hz, CH3), 1.43 (3H, d, J = 6.8 Hz, CH3), 1.74 (3H, s, CH3), 1.85 (3H, s, CH3), 2.03 (3H, s, CH3), 2.39 (3H, s, CH3), 2.40 (3H, s, CH3), 2.50 (3H, s, CH3), 2.59 (1H, m, CH), 2.78 (1H, m, CH), 4.22 (1H, m, CH), 4.70 (1H, m, CH), 6.87 (1H, s, CH), 7.00 (1H, s, CH), 7.32 (1H, s, CH), 7.54 (1H, s, CH).

Meth~Tlation of Compound B to form Compounds F and G

OAc OAc O

WO 9$/34932 PCT/US98/02292 Me0 CH3 _ . _ Me0 CH3 HO CH3 OH OMe O
HO CH3 ~' Compound F
OMe OMe OH OH O CH3 \ \ CH3 I
v w w Compound B MeO~ O CH3 Me0 ~ ~ O~CH3 OMe OMe O
Compound G
To a cooled (0°C) solution of compound B (20 mg) in 1 mL
methylene chloride was added an excess of freshly prepared solution of diazomethane in methylene chloride. The solution was stirred at room temperature overnight. Additional diazomethane was added and the solution was allowed to stir another 24 hrs. HPLC analysis (ZORBAX RX
C-8, 4.6 x 250 mm, 70% aqueous acetonitrile +0.1%TFA, 1 mL per minute) indicated formation of two major compounds. Volatile materials were removed under a stream of nitrogen and the products were purified on a ZORBAX RX C-8 (22 x 250 mm) column. The compounds were eluted isocratically for 30 minutes with 60% aqueous acetonitrile containing 0.1% TFA followed by a gradient to 75% over 30 minutes. The flow rate was 10 mL per minute. Fractions eluting between 30 to 32, and 34 to 36 minutes were combined and lyophilized to give penta- (Compound F) and hexamethyl (Compound G) ethers, respectively, as yellow powders.

Compound F: EIMS (m/z): 6I6 (100%, M+),1NMR (8 in CDCl3 at 25 °C): 1.17 (3H, d, J = 6.8 Hz, CH3), 1.21 (3H, d, J =
7.2 Hz, CH3), 1.40 (3H, d, J = 6.0 Hz, CH3), 1.44 (3H, d, J = 6.4 Hz, CH3), 2.52 (1H, m, CH), 2.70 (1H, m, CH), 3.77 (3H, s, CH3), 3.86 (3H, s, CH3), 3.97 (3H, s, CH3), 4.04 (3H, s, CH3),4.07 (3H, s, CH3), 4.12 (1H, m, CH), 4.66 (1H, m, CH), 6.56 (1H, s, CH), 6.62 (1H, s, CH), 6.63 (1H, s, CH), 7.02 (1H, s, CH), 10.08 (1H, s, OH).
Compound G: EIMS (m/z): 630 (100%, M+), 1NMR (S in CDCl3 at 25 °C): 1.17 (3H, d, J = 6.8 Hz, CH3), 1.22 (3H, d, J =
7.2 Hz, CH3), 1.38 (3H, d, J = 6.4 Hz, CH3), 1.42 (3H, d, J = 6.4 Hz, CH3), 2.52 (1H, m, CH), 2.77 (1H, m, CH), 3.50 (3H, s, CH3), 3.75 (3H, s, CH3), 3.84 (3H, s, CH3), 3.94 (3H, s, CH3), 3.98 (3H, s, CH3),4.06 (3H, s, CH3), 4.12 (1H, m, CH), 4.66 ( 1H, m, CH), 6.49 ( 1H, s, CH), 6.61 ( 1H, s, CH), 6.84 ( 1H, s, CH), 7.06 (1H, s, CH).

HIV Integrase Substrate Cleavage An assay for trimming of the 3' and of HIV long terminal repeat terminus by HIV-1 integrase was conducted according to LaFemina, R.L. et ail., J. Virol 10, 5624 (1991), herein incorporated by reference for these purposes. To assay inhibition of HIV integrase substrate cleavage, the reaction was conducted with inhibitor having various concentrations in the range of 0.75 to 100 ~M. Results follow:
Compound I r 2 ~.M
2 ~M
C 3 ~.M
D 1 ~.M
E 50 ~.M
F 40 ~,M
60 ~.M

strand Transfer A sav for HIV Inte~ra~P
A microtiter assay for ligation of processed donor (HIV) DNA to unspecific, nicked host DNA was conducted according to Hazuda, D.J. et ul., Nucl. Acids, Res. 22, 1121 (1994), herein incorporated by reference for these purposes. To assay inhibition of such strand transfer by HIV integrase, the reaction was conducted with inhibition having various concentrations in the range of 0.75 to 100 ~M.
Representative results follow.
Com op and I r A 12 ~,M
12 ~,M
C 9 ~.M
D 4 ~.M

Oral Composition As a specific embodiment of an oral composition of a compound of this invention, 50 mg of a compound of the present invention is formatted with sufficient finely divided lactose to provide a total amount of 580 to 590 mg to fill a size 0 hard gelatin capsule.
While the foregoing specification teaches the principles of the present invention, with examples provided for the purpose of illustration, it will be understood that the practice of the invention encompasses ail of the usual variations, adaptations, or modifications, as come within the scope of the following claims and its equivalents.

,. . ~ , ~ ,y.. . s A..

Claims (19)

WHAT IS CLAIMED:

1. The compound selected from:

or a pharmaceutically acceptable salt thereof.

2. The compound according to Claim 1 selected from:

,and or pharmaceutically acceptable salts thereof.

3. The compound according to Claim 1 selected from:

4. A pharmaceutical composition useful for inhibiting HIV integrase, comprising an effective amount of a compound according to Claim 1.

5. The pharmaceutical composition of Claim 4, useful for treating infection by HIV, or for treating AIDS or ARC.

6. A pharmaceutical composition comprising a therapeutically effective amount of a compound of Claim 1 in combination with a therapeutically effective amount of an AIDS
treatment agent selected from:
(a) an AIDS antiviral agent, (b) an immunomodulator, and (c) an anti-infective agent.

7. The pharmaceutical composition according to Claim 6 wherein the AIDS antiviral agent is:
N-(2(R)-hydroxy-1(S)-indanyl)-2(R)-phenylmethyl-4(S)-hydroxy-5-(1-(4-(3-pyridylmethyl)-2(S)-N'-(t-butylcarboxamido)-piperazinyl))-pentaneamide, or a pharmaceutically acceptable salt thereof.

8. A pharmaceutical composition made by combining the compound of Claim 1 and a pharmaceutically acceptable carrier.

9. A process for making a pharmaceutical composition comprising combining a compound of Claim 1 and a pharmaceutically acceptable carrier.

10. A method of inhibiting HIV integrase, comprising the administration to a mammal in need of such treatment a therapeutically effective amount of a compound of structural formula I:
wherein:
R1 is independently selected from:
(a) hydrogen, (b) C1-6 alkyl, and (c) C1-6 alkylcarbonyl-at each occurrence;

-X- is selected from:

(a) a carbon-carbon single bond, and (b) an oxygen atom bound to adjacent carbon atoms; and the dotted line, a, is represents a single bond or a double bond;
or a pharmaceutically acceptable salt thereof.

11. A method of treating infection by HIV, or of treating AIDS or ARC, comprising the administration to a mammal in need of such treatment a therapeutically effective amount of a compound of structural formula I:
wherein:
R1 is independently selected from:
(a) hydrogen, (b) C1-6 alkyl, and (c) C1-6 alkylcarbonyl-at each occurrence;
-X- is selected from:
(a) a carbon-carbon single bond, and (b) an oxygen atom bound to adjacent carbon atoms; and the dotted line, a, is represents a single bond or a double bond;

or a pharmaceutically acceptable salt thereof.

12. The method according to Claim 11 additionally comprising the administration of a therapeutically effective amount of another AIDS treatment agent selected from:
(a) an AIDS antiviral agent, (b) an immunomodulator, and (c) an anti-infective agent.

13. The method according to Claim 12 wherein the AIDS
antiviral agent is:
N-(2(R)-hydroxy-1(S)-indanyl)-2(R)-phenylmethyl-4(S)-hydroxy-5-(1-(4-(3-pyridylmethyl)-2(S)-N'-(t-butylcarboxamido)-piperazinyl))-pentaneamide.

14. A biologically pure culture of MF6252 (ATCC 74396).

15. A culture of MF6252 (ATCC 74396).

16. A biologically pure culture of MF6252 (ATCC 74396) or a mutant thereof capable of producing a compound according to Claim 2 in recoverable amounts.

17. A culture of MF6252 (ATCC 74396) or a mutant thereof capable of producing a compound according to Claim 2 in recoverable amounts.

18. A process for making a compound of Claim 2, comprising cultivating MF6252 (ATCC 74396) or a mutant thereof, under conditions suitable for the formation of the compound and recovering the compound.

19. A process for making a compound of Claim 2 which comprises:

(a) fermenting a culture of MF6252 (ATCC 74396), Fusarium sp. or a mutant thereof to produce a fermentation broth, (b) extracting the fermentation broth with an organic solvent, (c) isolating the compounds of Claim 2.