WO1994025465A1

WO1994025465A1 - SUBSTITUTED METHYLENEDIOXY[3',4':6,7]INDOLIZINO-[1,2-b]QUINOLINONES

Info

Publication number: WO1994025465A1
Application number: PCT/US1994/004866
Authority: WO
Inventors: William Dennis Kingsbury; Israil Pendrak
Original assignee: Smithkline Beecham Corporation
Priority date: 1993-05-03
Filing date: 1994-05-03
Publication date: 1994-11-10
Also published as: MX9403275A; NZ266094A; JPH08509742A; AU684777B2; CA2161980A1; EP0699201A1; AU6670494A; EP0699201A4

Abstract

Antiviral substituted methylenedioxyindolizino[1,2-b]quinolinones, compositions comprising such compounds, and a method of treating viral infection by using such compounds are disclosed herein.

Description

SUBSΗTUTΕD METHYLENEDIOXYtS'^'^ lINDOLIZINO- [ 1 ,2-b]QUINOLINONES

This patent application is a continuation-in-part of U.S. Serial No. 08/057,133, filed on May 3, 1993 by Pendrak et al.

SCOPE QF THE INVENTION This invention relates to antiviral compounds, pharmaceutical compositions thereof, and a method of treating viral infections. More specifically, this invention relates to certain indolizino[ l,2-b]-quinolinyl derivatives which have antiviral activity.

BACKGROUND OF THE TNVRNTTON

Certain lH-pyrano[3\4':6,7]indohzino[l,2-b]quinolinones are known to have cytotoxic and antiviral activity. Camptothecin is an example of one such compound. It is a water-insoluble, cytotoxic alkaloid produced by Camptotheca acuminata trees indigenous to China and Nothapodytes foetida trees indigenous to India. Camptothecin and its close congeners are known to inhibit eukaryotic topoisomerase I. The cytotoxic and antitumor activity of camptothecin and its close congeners is due to this inhibition of eukaryotic topoisomerase I (Cancer Res. 1988, 48, 1722; Molec. Pharmacol. 1988, 34, 755). Compounds that are related in structure to camptothecin but do not inhibit eukaryotic topoisomerase I are not cytotoxic to mammalian cells and have no antitumor activity (J. Med. Chem. 1988, 32, 715; Cancer Res. 1989, 49, 1465; Cancer Res. 1989, 49, 4358). Camptothecin has been shown to have an effect on viruses by a number of investigators in laboratory settings. Although camptothecin has demonstrated antiviral activity in in vitro tissue culture systems, camptothecin and its close analogs that have a hydroxylactone moiety cannot be considered as useful in vivo antiviral agents because they inhibit mammalian topoisomerase I, inhibit host cell DNA replication, and are cytotoxic to mammalian cells. Furthermore, camptothecin is not expected to be attractive for drug development as an antiviral agent because of unacceptable dose-limiting toxicity, unpredictable toxicity, poor aqueous solubility, and/or unacceptable shelf life stability.

There is a need for new antiviral agents. Some substituted 1H- pyrano[3',4':6,7]indolizino-[l ,2-b]quinolinones that lack the E-ring α-hydroxy lactone moiety of camptothecin have been shown to be non-cytotoxic to mammalian cells and to lack antitumor activity (Ann. Rev. Pharmcol. Toxicol. 1977, 17, 117; J. Med. Chem. 1989, 32, 715). This is because these compounds do not contain the essential structural features required to inhibit eukaryotic topoisomerase I. But it has been found that certain 7-ethyl-7-hydroxy-7,8,ll,13-tetrahydro-10H- dioxolo[4,5g]pyrano[3',4 ':6,7]indolizino[ 1 ,2-b]quinolinone-8, 11 -diones (hereinafter "methylenedioxyindolizino[l,2-b]quinolinones") lacking the hydroxylactone moiety do have antiviral activity without the undesirable features of camptothecin. As such they are useful for treating viral infections.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a method for treating viral infections, which method comprises administering to an infected host in need thereof an effective amount of a compound of Formula I, or a pharmaceutically acceptable salt thereof, alone or in combination with a carrier, diluent or excipient.

wherein:

R is =O, -OH, and OR¹;

Rl is -COR⁴, or -P(O)(OH)R⁵ wherein:

R3 is -H or lower alkyl;

R⁴ is -CR³R⁶R⁷;

-(CH₂)_nCH₂R⁷ (where n=0-3);

-(CH₂)nCH₂COOH (where n=0-3);

-NR9R10_; -NH(CH₂)_nCH₂R⁷ (where n = 1-3); and

-NH(CH₂)_nCH₂COOH (where n = 0-3);

R⁵ is OH or CH NH₂;

R6 is H or the side chain of any naturally occuring α-amino acid;

R7 is -NR9RlO

. . _ - v_ _whe__e X is any pharmaceutically acceptable anion;

R8 is lower alkyl;

R9 and R¹^ are independently selected from the group consisting of -H, -Cl-6 alkyl, and R^ and R¹^ taken together to form a 5-7 membered saturated heterocyclic ring containing the nitrogen on which R^ and R¹^ are substituted; and R¹¹ is -CH₂R¹², wherein:

/ \ / \

-N O, -N NCH₃, -OH

R¹² is -N(CH₃)₂ ^ ' ^ ^/ In another aspect, this invention relates to novel compounds of Formula I, and pharmaceutically acceptable salts thereof.

In yet another aspect, this invention relates to a composition comprising a novel compound of Formula I in combination with an acceptable carrier, excipient or diluent, particularly a pharmaceutically acceptable carrier, excipient or diluent

DETAILED DESCRIPTION OF THE INVENTION

Definitions

The terms below, defined as follows, are used in describing the present invention throughout this application.

"Aliphatic" is intended to include saturated and unsaturated radicals. This includes normal and branched chains, saturated or mono or poly unsaturated chains where both double and triple bonds may be present in any combination. The phrases "lower alkyl" and "C1-.5 alkyl" refer to and mean an alkyl group of 1 to 6 carbon atoms in any isomeric form, but particularly the normal or linear form. "Lower alkoxy" means the group lower alkyl-O-. "Halo" means fluoro, chloro, bromo or iodo. "Acyl" means the radical having a terminal carbonyl carbon.

The phrase "5-7 membered saturated heterocyclic ring containing the nitrogen" is intended to include saturated rings such as piperidine, pyrrolidine, morpholine, piperazine, and N-alkyl piperazine.

Salts of any sort may be made from these compounds, provided there is an acidic group present or a sufficiently basic nitrogen. Particularly preferred are the pharmaceutically acceptable salts of the instant compounds. These latter salts are those which are acceptable in their application to a pharmaceutical use. By that it is meant that the salt will retain the biological activity of the parent compound and the salt will not have untoward or deleterious effects in its application and use in treating diseases. .

Pharmaceutically acceptable salts are prepared in a standard manner. The parent compound in a suitable solvent is reacted with an excess of an organic or inorganic acid, in the case of acid addition salts of a base moiety, or an excess of organic or inorganic base in the case where there is an acid group. Representative acids are hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, acetic acid, maleic acid, succinic acid or methanesulfonic acid. Cationic salts are readily prepared from metal bases such as sodium, potassium, calcium, magnesium, zinc, copper or the like and ammonia. Organic bases include the mono or disubstituted amines, ethylenediamine, piperazine, amino acids, caffeine, and the like. Here and throughout this application, the ring system of the compounds of the present invention are numbered according to Formula II.

If a chiral center or another form of an isomeric center is created by some combination of substituents, in a compound of the present invention, all forms of such isomer(s) are intended to be covered herein. Inventive compounds containing a chiral center may be used as a racemic mixture or the mixture may be separated and an individual enantiomer may be used alone.

The present invention provides a method for the treatment of viral infections caused by certain DNA viruses comprising administering to an infected animal, preferably a mammal, most preferably a human, in need thereof an effective amount of a compound of Formula I as described hereinabove, or a pharmaceutically acceptable salt thereof, alone or in combination with a carrier, excipient or diluent

The present invention also provides compounds, and pharmaceutically acceptable salts thereof, which exhibit antiviral activity, said compounds having the structure represented by Formula I hereinabove. More specifically, these compounds and the present method are especially useful in treating the following pathogens in humans:

Herpes Simplex virus types 1 and 2 (HSV-1 and HSV-2);

Cytomegalovirus (CMV);

Varicella Zoster Virus (VZV); No unacceptable toxicological effects are expected when compounds of the present invention are administered in accordance with the present invention.

A preferred method for treating viral infections according to the present invention uses the following compounds of Formula I:

7-Acetyl-8-methyldioxolo[4,5-^]indolizino[l,2-b]quinolin-9(llH)-one; (±)-7-( 1 -Hydroxyethyl)-8-methyldioxolo[4,5-g]indolizino[ 1 ,2-b]quinolin-

9(ll )-one;

(±)-7-[ 1 ( Aminoacetyl)oxy]ethyl]-8-methyldioxolo[4,5-^]indolizino[ 1 ,2- b]quinolin-9(l l )-one hydrotrifluoroacetate; 7-Acetyl-12-dimethylaminomethyl-8-methyldioxolo [4,5-g] indolizino [l,2-b]quinolin-9(HH)-one; and

7-Acetyl-12-hydroxymethyl-8-methyldioxolo [4,5-g] indolizino [1,2-b] quinolin-9(l lH)-one. Preferred compounds of the present invention include:

7- Acetyl-8-methyldioxolo[4,5-g]indolizino[ 1 ,2-b]quinolin-9( 1 l )-one;

(±)-7-( 1 -Hydroxyethyl)-8-medιyldioxolo[4,5-g]indolizino[ 1 ,2-b]quinolin- 9(ll//)-one;

(±)-7-[l(Ammoacetyl)oxy]ethyl]-8-methyldioxolo[4,5-g]indolizino[l,2- b]quinolin-9(llH)-one hydrotrifluoroacetate;

7-Acetyl-12-dimethylaminomethyl-8-methyldioxolo [4,5-g] indolizino [ 1 ,2-b]quinolin-9( 1 lΗ)-one; and

7-Acetyl-12-hydroxymethyl-8-methyldioxolo [4,5-g] indolizino [1,2-b] quinolin-9(l lH)-one. The compounds of the present invention can be prepared by the following methods.

There are several methods for preparing these compounds. One generic process comprises preparing a 1-keto indolizine adduct and then condensing this fragment with the appropriate substituted aminobenzaldehyde or aminoactophenone. Starting materials are commercially available or can be made by published methods. The reaction sequences are illustrated by Schemes I-iπ. Commerically available 2-pyrrolidone 1 can be alkylated with dimethyl sulfate to give ether 2 which can be condensed with acetonedicarboxylate to give indolizine 3. Methylation of 3 with methyl iodide at ambient temperature in the inert solvent produced 4, which can be hydrolyzed with an aqueous base to give 5 followed by decarboxylation to produce 6. Triflation of 6 with N-phenyltriflimide in DMF in the presence of base, like triethylamine, can give 7, which can be reacted via Heck reaction with n- butylvinylether in the presence of palladium catalyst and base to give 8. Hydrolysis of 8 with acid, like 3N HC1, can give 9 which can be protected as a ketal using ethyleneglycol and hydrochloride gas to give 10. Compound 10 can be oxidized using Davis reagent and base to give alcohol 11 which can be further oxidized with pyridiniumchlorochromate in methylene chloride to give ketone-ketal 12. Friedlander condensation of compound 12 with aminopiperinal 13 in the presence of p-tolunesulfonic acid in toluene and subsequent hydrolysis with acid, like 3N HC1, can give the title compound 14 (Scheme II). Aminoacetophenone 20 can be prepared in four steps by first nitrating methylenedioxyacetophenone 15 with nitric acid to give compouond 16 which can be brominated with bromine in dioxane to produce compound 17. Reaction of 17 with hydrazine 18 in acetonitrile can give compound 19 which can be reduced with nickel boride to give amine 20. Condensation of compound 12 and 20 as described previously can give the title compound 21 (Scheme II). Reaction of 17 with with sodium acetate in dimethylformamide produced compound 22 (Scheme HI). Reduction of 22 with nickel boride can give compound 23 which can be condensed with compound 12 and hydrolysed as described previously to produce the title compound 24.

SCHEME

3

SCHEME II

SCHEME II

The assay used to test the compounds of the present invention for antiviral activity is well-known. A generalized description of the assay follows.

Well plates are seeded with the appropriate cells at a concentration of lxl 0^ cells per well suspended in 0.5 mL of Earle's Minimum Essential Medium (EMEM) containing 10% fetal bovine serum (FBS) and antibiotic and antimycotic solution. After the cells are 80-90% confluent (24 hours), old medium is removed and washed with Hank's buffered saline solution (HBSS). Cells are then infected for 1 hour at 37°C with 100-200 plaque forming units per well of a herpes simplex virus suspended in 250 mL HBSS. Following adsorption, the following are added: A) 250 mlVwell 2 x EMEM containing Human IgG (Sigma Chemical Co., St Louis, Mo.) (ca. 0.1 mg/mL);

B) 250 mL well EMEM containing 10% FBS and antibiotic/antimycotic solution; and

C) 250 mlJwell HBSS containing appropriately diluted compound. After 24-48 hours (best time determined by observation of plaques under a microscope), old medium is aspirated off. Each well is stained with a selected stain solution (0.5% crystal violet in MeOH:H₂O 7:3) and then rinsed with water, air dried, and the plaques are counted. Compound effectiveness is evaluated in terms of percent plaque reduction as compared to untreated, infected controls. This assay can be used to test compound activity against many other viruses besides herpes simplex by simply modifying the cell type used in the first step to match the virus being tested, and otherwise following the procedure outlined above. Other cell types which can be used in this assay include mouse mammary tumor cells, human lung fibroblasts, sheep chorioplexus cells, and green monkey kidney cells. Alternatively, other assays can be used to determine the antiviral activity of the present compounds. Such assays include the following types: cell count clonogenic, cytopathic effect dish-colony formation, microtiter-growth inhibition, thymidine incorporation and yield reduction. Each of these assays is well-known and is available either from the literature or from a commercial testing lab. The present invention provides pharmaceutical compositions prepared from the compounds of Formula I. These compositions have both a human and veterinary utility, and comprise an excipient or carrier which is acceptable for the intended pharmaceutical end use and at least one inventive compound. For example, if a veterinary use is intended, the carrier may be a liquid, or spray, or may be formulated in a solid, non-degradeable or degradeable form for insertion in the rumen. Selected excipients and carriers may be employed to prepare compositions acceptable or adaptable for humans use. An effective amount of the pharmaceutical compositions of the present invention may be contained in one embodiment, such as in a single pill, capsule, or pre-measured intravenous dose or pre-filled syringe for injection. Alternatively, as is frequently the case, the composition will be prepared in individual dose forms where one unit such as a pill, will contain a sub-optimal dose but the user will be instructed to take two or more unit doses per treatment. When the composition is presented as a cream, it will contain a discrete amount of drug and the user will apply some amount of the cream one or more times until the disease is in remission or has been effectively treated. Concentrates for later dilution by the end user may also be prepared, for instance for intravenous (IV) formulations and multi-dose injectable formulations.

Carriers or diluents contemplated for use in these compositions are generally known in the pharmaceutical formulary arts. Reference to useful materials can be found in well known compilations such as Remington's Pharmaceutical Sciences. Mack Publishing Co., Easton, Pa.

The nature of the composition and the pharmaceutical carrier or diluent will, of course, depend upon the intended route of administration, for example whether by intravenous and intramuscular injection, parenterally, topically, orally, or by inhalation. For parenteral administration the pharmaceutical composition will be in the form of a sterile injectable liquid such as an ampule or an aqueous or nonaqueous liquid suspension.

For topical administration the pharmaceutical composition will be in the form of a cream, ointment, liniment, lotion, paste, spray or drops suitable for administration to the skin, eye, ear, nose or genitalia.

For oral administration the pharmaceutical composition will be in the form of a tablet capsule, powder, pellet, atroche, lozenge, syrup, liquid, or emulsion.

The pharmaceutical carrier employed may be, for example, either a solid or liquid. When the pharmaceutical composition is employed in the form of a solution or suspension, examples of appropriate pharmaceutical carriers or diluents include: for aqueous systems, water; for non-aqueous systems: ethanol, glycerin, propylene glycol, olive oil, com oil, cottonseed oil, peanut oil, sesame oil, liquid paraffins, and mixtures thereof with water, for solid systems: lactose, terra alba, sucrose, talc, gelatin, agar, pectin, acacia, magnesium stearate, stearic acid, kaolin and mannitol; and for aerosol systems: dichlorodifluoromethane, chlorotrifluoroethane and compressed carbon dioxide. Also, in addition to the pharmaceutical carrier or diluent the instant compositions may include other ingredients such as stabilizers, antioxidants, preservatives, lubricants, suspending agents, viscosity modifiers and the like, provided that the additional ingredients do not have a detrimental effect on the therapeutic action of the instant compositions. Similarly, the carrier or diluent may include time delay material well known to the art, such as glyceryl monostearate or glyceryl distearate alone or with a wax, ethylcellulose, hydroxypropylmethylcellulose, mediylmethacrylate and the like.

A wide variety of pharmaceutical forms can be employed. Thus, if a solid carrier is used, the preparation can be tableted, placed in a hard gelatin capsule in powder or pellet form or in the form of a troche or lozenge. The amount of solid carrier will vary widely but preferably will be from about 25 mg to about 1 gram. If a Uquid carrier is used, the preparation will be in the form of a syrup, emulsion, soft gelatin capsule, sterile injectable solution or suspension in an ampule or vial or nonaqueous liquid suspension. To obtain a stable water soluble dose form, a pharmaceutically acceptable salt of the compound of Formula I is dissolved in an aqueous solution of an organic or inorganic acid or base. If a soluble salt form is not available, the compound of Formula I may be dissolved in a suitable co-solvent or combinations thereof. Examples of such suitable cosolvents include, but are not limited to, alcohol, propylene glycol, polyethylene glycol 300, polysorbate 80, glycerin and the like in concentrations ranging from 0-60% of the total volume. It will be appreciated that the actual preferred dosages of the compounds used in the compositions of this invention will vary according to the particular complex being used, the particular composition formulated, the mode of administration and the particular site, host and disease being treated. It is expected that these compounds will be active in the concentration ranges of two commercial antiviral drugs, Cytovene (ganciclovir) and Zovirax (acyclovir). The latter is manufactured in 200 mg capsules with instructions for treating herpes simplex viral infections by taking one capsule every 4 hours, but not to exceed 5 capsules per day.

EXAMPLES

In the following synthetic examples, temperature is in degrees Centigrade

(°C). Unless otherwise indicated, all of the starting materials were obtained from commercial sources. Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. These Examples are given to illustrate the invention, not to limit its scope. Reference is made to the claims for what is reserved to the inventors hereunder. EXAMPLE 1 Preparation of 7-Acetvl-8-methvldioxolo T4.5-f> 1 indolizino π.2-fr 1 quinolin-9fl lH>

1A) 2-Metøp y-pyrroling

2-Pyrrolidone (850 g, 760 mL, 10 mol; Aldrich) was added dropwise, over a period of two hours, to a stirred solution of dimethyl sulfate (1260 g, 945 mL, 10 mol; Aldrich) under an argon atmosphere, causing the temperature to rise to 45 °C. When addition was complete the clear mixture was stirred for 16h at 60°C. It was then poured onto ice and saturated K CO3, and extracted with ether (2 X IL). The combined organic phase was washed with brine , dried (Na₂SO4), and solvent removed on the rotary evaporator, keeping the heating bath at 20°C. The residual liquid was distilled under vacuum into a chilled receiver to yield, after a small forerun 635 g (64%) of colorless liquid, b.p. 35°C / 15 Torn 1 NMR (400 MHz, CDCI3) δ 3.8 (s, 3H, OCH3), 3.65 (t, 2H, CH₂-N), 2.45 (t, 2H, CH2-N), 2.1 (m, 2H, -CH₂-).

IB) 7-Hvdroxv-8-ethoxvcarbonvl-2.3-dihvdro-lH-indolizin-5-one

The mixture of compound of Example 1(A) (100 g, 100 mL, 1 mol) and 1,3- diethyl acetonedicarboxylate (202 g, 182 mL, 1.5 mol, Aldrich) alone with triethylamine (10 mL) was kept at room temperature for 1.5 weeks. The crystals formed were separated by filtration and washed with petroleum ether and ethyl ether to give off white solid 94 g (41%), m.p. 131°C: NMR (400 MHz, CDCI3) δ 5.8 (s, 1H, olefin), 4.4 (m, 3H, ethyl ester), 4.15 (t, 2H, CH₂-NCO), 3.5 (t, 2H, CH - olefin), 2.25 (m, 2H, -CH2-), 1.4 (t, 3H, ethyl ester).

1C) 7-Hvdroxv-8-ethoxvcarbonvl-6-meth vl-2.3-dihvdro- 1 H-indolizin-5-one

To a solution of compound of Example 1(B) (10 g, 45 mmol) in dry THF (500 mL) under an argon atmosphere was added NaH (2 g, 49 mmol, 60% dispersion). The resulting mixture was stirred at room temperature for 10 min. Methyl iodide (2.8 mL, 45 mmol) was added and mixture stirred at room temperature for 96h. Solvent was evaporated and residue purified by flash column chromatography (silica, 0-2% methanol: CH₂α₂) to give white solid 5.7 g (54%): NMR (400 MHz, CDCI3) δ 11.4 (s, 1H, OH), 4.4 (m, 3H, ethyl ester), 4.15 (t, 2H, CH₂-NCO), 3.5 (t, 2H, CH₂-olefin), 2.25 (m, 2H, -CH₂-), 2.01 (s, 3H, CH3), 1.4 (t, 3H, ethyl ester)

ID) 7-Hydroxy-8-carboxy-6-methyl-2.3-dihydro-lH-indolizin-5-one To a solution of compound of Example 1(C) (1.2 g, 5 mmol) in methanol (30 mL), THF (20 mL) and H₂O (20 mL) was added LiOH (lg, 25 mmol) and mixture stirred at room temperature for 56h. Solvent was removed in vacuum. The resulting mixture was diluted with H₂O and acidified to (PH~5) with 3N HCI. The precipitated solid was filtered and washed with H₂O and dried in vacuum to give tan solid 0.8 g (76%): ¹ NMR (400 MHz, CD3OD) δ 4.23 (m, 2H, CH₂-NCO), 3.5 (t, 2H, CH -olefin), 2.35 (m, 2H, -CH₂-), 1.95 (s, 3H, CH3).

IE) 7-hvdroxv-6-methvl-2.3-dihvdro-indolizin-5-one The compound of Example 1(D) (0.8 g, 3.75 mmol) and 2,4,6- trichlorophenol (6 g) were heated at 220°C until evolution of carbon dioxide stopped.

The resulting mixture was cooled to room temperature and diluted with ethyl ether.

The precipitated solid was filtered and dried to give solid 0.62 g (98%): * NMR (400

MHz, CD3OD) δ 6.1 (s, IH, pyridyl), 4.23 (m, 2H, CH₂-NCO), 3.5 (t, 2H, CH2- olefin), 2.35 (m, 2H, -CH₂-), 1.95 (s, 3H, CH3).

IF) Trifluorometanesulfonic acid-6-methvl-5-oxo- 1.2.3.5-tetrahvdro-indolizin-7-vl-ester To the solution of compound of Example 1(E) (5 g, 30 mmol) in DMF (100 mL) was added triethylamine (12.6 mL, 90 mmol) alone with N-phenyltrifluorometanesulfonimide (16 g, 45 mmol). The resulting mixture was stirred at room temperature for lh. Solvent was removed in vacuum and residue purified by flash column chromatography (silica, 50-100% EtOAc: hexanes) to give tan solid 6.15 g (68%): 1 NMR (400 MHz, CDCI3) δ 6.15 (s, IH, pyridyl), 4.16 (t, 2H, -CH₂), 3.13 (t, 2H, -CH₂-), 2.24 (m, 2H, -CH₂), 2.13 (s, 3H, CH3).

1G) 7-π-Butoxv-vinvlV6-methyl-2.3-dihvdro-lH-indolizin-5-one

To the solution of compound of Example 1(F) (6.15 g, 20 mmol) in DMF (100 mL) was added triethylamine (5.5 mL, 40 mmol) alone with n-butyl vinylether (10.3 mL, 80 mmol). To the resulting mixture was added Pd(OAc)2 (0.27 g, 1.2 mmol) alone with l,3-bis(diphenylphosphino)propane (0.49 g, 1.2 mmol). The resulting mixture was stirreed at 60°C for 5h. Solvent was removed in vacuum and residue purified by flash column chromatography (silica, 30-60% EtOAc: hexane) to give oil 5 g (89%): I NMR (400 MHz, CDCI3) δ 6.15 (s, IH, pyridyl), 4.35 (d, IH, olefin), 4.16 (m, 3H, -CH₂; olefine), 3.79 (t, 2H, CH₂-O), 3.1 (T, 2H, -CH₂-), 2.2 (m, 5H, -CH3; -CH₂-), 1.72 (m, 2H, alkyl), 1.48 (m, 2H, alkyl), 0.95 (t, 3H, alkyl).

IH) 7-Acetvl-6-methvl-2.3-dihvdro-lH-indolizin-5-one

To the solution of compound of Example 1(G) (5 g, 20 mmol) in glacial acetic acid (10 mL) was added 3N HCI (3 mL) and the reaction mixture was stirred at room temperature for lh. Solvent was removed in vacuum and residue resuspended in EtOAc, washed with 5% NaHCO3, NaCl, dried (Na₂SO4). Solvent was removed in vacuum and residue purified by flash column chromatography (silica, 40-100% EtOAc: hexane and 0-5% methanol: CH₂C1₂) to give solid 2.3 g (52%). m.p. 101-102°C.

II) 6-Methvl-7-(2-methvl-ri.31-dioxolan-2vlV2.3-dihvdro-lH-indolizin-5-one HCI gas was bubled in to the solution of compound of Example 1(H) (2 g, 10.4 mmol) in ethelyneglycol (50 mL) at 0°C. The resulting solution was alowed to warm-up to room temperature and stired at room temperature for 14h. The resulting mixture was poored in to the solution NH4OH and ice. The mixture was extracted with CH₂Q₂, washed with H₂O, NaCl and dried (Na₂SO4). Solvent was removed in vacuum and residue purified by flash column chromatography (silica, 0-5% methanol: CH₂C1₂) to give solid 2.13 g (86%). ¹ NMR (400 MHz, CDCI3) δ 6.37 (s, IH, pyridyl), 4.14 (t, 2H, -CH₂-), 4.02 (m, 2H, ketal), 3.73 (m, 2H, ketal), 3.04 (t, 2H, -CH₂-), 2.27 (s, 3H, -CH3), 2.16 (m, 2H, -CH₂-), 1.61 (s, 3H, -CH3).

1J) l-Hvdroxv-6-methvl-7-f2-methvl-ri ■31-dioxolan-2vlV2.3-dihvdro- 1H- indolizin-g-ong To the solution of diisopropylamine (1.89 mL, 13.6 mmol) in THF (20 mL) at

-78°C was added n-butyllithium (5.4 mL, 13.6 mmol) and the resulting mixture was stirred at -78°C for 10 min. The solution of compound of Example 1(1) (2.13g, 9 mmol) in THF (100 mL) was added via addition funnel and the resulting mixture was stirred at -78°C for 10 min. Davis reagent (3.54 g, 18 mmol) in THF (20 mL) was added at once and the resulting mixture was stirred at -78°C for lh. Saturated solution of NH4CI (20 mL) was added at -78°C and the resulting mixture was extracted with CH₂Q₂. Aqueous layer was acidified with 3N HCI and extracted with with CH₂α₂. The combined organic fractions were washed with H₂O, brine and dried (Na₂SO4). Solvent was removed in vacuum and residue purified by flash column chromatography (silica, 0-7% methanol: CH₂C1₂) to give foam 1.16 g (51%). ! NMR (400 MHz, CDCI3) δ 6.66 (s, IH, pyridyl), 5.21 (br s, IH, -CH- OH), 4.14 (m, IH, -CH₂-), 4.04 (br s, IH, -OH), 3.99 (m, 3H, ketal, -CH₂-), 3.73 (m, 2H, ketal), 2.46 (m, IH, -CH₂-), 2.27 (s, 3H, -CH3), 2.16 (m, IH, -CH -), 1.61 (s, 3H, -CH3).

IK) 6-Methyl-7-f2-methyl-π.31-dioxolan-2ylV2.3-dihvdro-lH-indolizin-1.5-dione

To the solution of compound of Example 1(J) (l.lg, 4.3 mmol) in CH₂Q₂ (100 mL) was added pyridiniumchlorochromate (1.89 g, 8.7 mmol) and the resulting mixture was stirred at room temperature for 12h. The mixture was diluted with CH₂Q₂ and the resulting residue was filtered through the bed of celite. Solvent was removed in vacuum and residue purified by flash column chromatography (silica, 0- 3% methanol: CH₂α₂) to give foam 0.8 g (74%). ^lH NMR (400 MHz, CDCI3): δ 7.20 (s, IH, pyridyl), 4.28 (br s, 2H, -CH₂-), 4.07 (br s, 2H, ketal), 3.73 (br s, 2H, ketal), 2.89 (br s, 2H, -CH₂-), 2.42 (s, 3H, -CH3), 1.61 (s, 3H, -CH3).

IL) 7-Acetyl-8-methyldioxolo f4.5-g 1 indolizino fl.2-b 1 quinolin-9(l lHVone

To the solution of compound of Example 1(K) (O.lg, 0.4 mmol) in toluene (10 mL) was added aminopiperinal (73 mg, 0.44mmol) alone with p-toluenesulfonicacid (2mg, catalyst). The resulting mixture was refluxed uner Dean-Stark trap for 12h. The mixture was cooled and diluted with hexane and Et₂O. The precipitated tan solid was filtered and dried in vacuo to give ketal 65mg (43%). *H NMR (400 MHz, CDCI3): δ 8.1 (s, IH, 12- quinolyl), 7.57 (s, IH, 13-quinolyl), 7.48 (s, IH, 4-quinolyl), 7.14 (s, IH, 6-pyridyl), 6.18 (s, 2H, O-CH₂-O), 5.19 (s, 2H, 11-CH -), 4.09 (m, 2H, ketal), 3.84 (m, 2H, ketal), 2.45 (s, 3H, -CH3), 1.72 (s, 3H, -CH3).

To the ketal above (65 mg, 0.17 mmol) in glacial acetic acid (5 mL) was added 3N HCI (1 mL). The resulting mixture was heated at 70°C for lh. The mixture was diluted with H₂O and extracted with CH₂Q₂. The oragnic layer was washed with brine and dried (Na2SO4). Solvent was removed in vacuo to give yellow solid 28 mg (50%). *H NMR (400 MHz, CDCI3+ CD3OD): δ 8.23 (s, IH, 12-quinolyl), 7.49 (s, IH, 13-quinolyl), 7.35 (s, IH, 4-quinolyl), 7.19 (s, IH, 6- pyridyl), 6.20 (s, 2H, O-CH₂-O), 5.23 (s, 2H, 11-CH₂-), 2.64 (s, 3H, -CH3), 2.32 (s, 3H, -CH3); Anal. (Ci9Hi4N₂O4- 0.5 H₂O) calcd.: C, 66.47; H, 4.40; N, 8.16 found: C, 66.41; H 4.20; N, 8.14. m.p >300°C.

EXAMPLE 2 Preparation of 7-Acetyl-12-dimethylaminomethyl-R-methyldioxolo f4.5-g 1 indolizino π.2-b 1 quinolin-9O lHVone.

2A) 1 -(2-nitro-phenvnetanone

To the cooled 65% HNO3 (200 mL) was added 3,4-Methylenedioxyacetophenone (41 g, 0.25 mol; Aldrich) and the resulting mixture was stirred at 40°C for lh with the evolution of heat. When the evolution of the heat ceased the mixture was poured into the ice. The water was decanted and the resulting gum was triturated with methanol. The product soUdified and filtered to give solid 40g (76%). ^l NMR (400 MHz, CDCI3): δ 7.55 (s, IH, aromatic), 6.76 (s, IH, aromatic), 6.19 (s, 2H, O-CH₂-O), 2.56 (s, 3H, - CH3); m.p ll2°C.

2B) 2-Bromo- 1 -(2-nitro-phenvnethanone To the solution of compound of Example 2(A) (10 g, 47.8 mmol) in dioxane

(30 mL) was added dropwise the solution of bromine (2.5 mL, 48.3 mmol) in dioxane (100 mL) via the addition funnel. The resulting mixture was stirred at room temperature for 4h. Solvent was removed in vacuum and mixture was diluted with Et2θ, washed with 5% NaHCO3, H₂O, brine and dried (Na₂SO4). Solvent was removed in vacuum and residue purified by flash column chromatography (siUca, 0- 60% Et₂O: hexane) to give lacrymatory solid 8g (58%). *H NMR (400 MHz, CDCI3): δ 7.62 (s, IH, aromatic), 6.84 (s, IH, aromatic), 6.22 (s, 2H, O-CH₂-O), 4.23 (s, 2H, CH₂Br).

2C) N'-benzvlidine-N.N-dimethvl-hvdrazine

To the solution of benzaldehyde (5 g, 47 mmol; Aldrich) in ethanol (250 mL) at 10°C was added dropwise N,N-dimethylhydrazine (5.37 mL, 70.6 mmol; Aldrich) in ethanol (50 mL). The resulting mixture was allowed to warm up to room temperature and was stirred at room temperature for 30 min, and then refluxed for 20h. Solvent was removed in vacuum and resulting mixture was diluted with H₂O, extracted with Et₂O. Organic layer was washed with brine and dried (Na₂SO4). Solvent was removed in vacuum to give light yellow oil 5.2 g (74%). *H NMR (400 MHz, CDCI3): δ 7.6 (m, 2H, aromatic), 7.3 (m, 2H, aromatic), 7.2 (m, 3H, aromatic; CH=N), 2.95 (s, 6H, dimethylamino). 2D) 2-Dimethvlamino- 1 -f 2-nitro-phen vlV ethanone

To the solution of compound of Example 2(B) (0.5 g, 1.73 mmol) in CH3CN (5 mL) was added compound of Example 2(C) (0.26 g, 1.73 mmol) and the resulting mixture was allowed to stand at room temperature for 24h. The product precipitated and filtered to give soUd 126 mg (25%). H NMR (400 MHz, CDCI3+CD3OD): δ 7.65 (s, IH, aromatic), 7.19 (s, IH, aromatic), 6.27 (s, 2H, O-CH₂-O), 4.67 (s, 2H, CH2N⁺(CH3)2), 3.09 (s, 6H, dimethylamino⁺).

2E) l-(2-Amino-phenyl')-2-dimethylamino-ethanone To the solution of compound of Example 2(D) (0.126 g, 0.38 mmol) in methanol (5 mL) was added IN HCI (3 mL) alone with Ni₂B (200 mg) and the resulting mixture was heated at 60°C for lh. The mixture was diluted with H₂O and extracted with EtOAc. The oraganic layer was washed with brine and dried (Na₂SO4). Solvent was removed in vacuum to give solid 76 mg (90%). *H NMR (400 MHz, CDCI3): δ 7.28 (s, IH, aromatic), 6.45 (br s, 2H, -NH2), 6.13 (s, IH, aromatic), 5.9 (s, 2H, O-CH₂-O), 3.52 (s, 2H, CH₂N(CH3)₂), 2.34 (s, 6H, dimethylamino).

2F) 7-Acetvl-12-dimethvlaminomethvl-8-methvldioxolo T4.5-p 1 indolizino T1.2- b 1 qvιinolin-9f llHVons Compound of Example 1(K) (71 mg, 0.28 mmol) and compound of Example

2(E) (71 mg; 0.31 mmol) were reacted following the procedure of Example 1(L). Solvent was evaporated and residue purified by flash column chromatography (silica, 0-10% methanol: CH₂Q₂) to give ketal as yellow solid 25 mg (25%). *H NMR (400 MHz, CDCI3): δ 7.61 (s, IH, quinolyl), 7.49 (s, IH, quinolyl), 7.45 (s, IH pyridyl), 6.15 (s, 2H, O-CH₂-O), 5.23 (s, 2H, 11-CH₂), 4.07 (m, 2H, ketal), 3.82 (m, 2H, ketal), 3.80 (s, 2H, CH₂N(CH3)₂), 2.45 (s, 3H, -CH3), 2.29 (s, 6H, dimethylamino), 1.71 (s, 3H, -CH3).

The ketal above was hydrolyzed following the procedure of Example 1(L). The resulting residue was lyophilized to give solid 12 mg (65%). *H NMR (400 MHz, D O): δ 7.4 (s, IH, quinolyl), 7.2 (s, IH, quinolyl), 7.01 (s, IH pyridyl), 6.3 (s, 2H, O-CH₂-O), 5.18 (s, 2H, 11-CH₂), 3.65 (s, 2H, CH₂N(CH3)₂), 2.98 (s, 6H, dimethylamino⁺)2.66 (s, 3H, -CH3), , 2.17 (s, 3H, -CH3). EXAMPLE Preparation of 7-Acetvl-12-hvdroxvmethvl-R-methvldioxolo T4.5-p 1 indolizino H.2-b 1 quiτ-olin-9d lHVone.

3A) Acetic acid-2-f2-nitro-phenvlV2-oxo-ethvl ester To the solution of compound of Example 2(B) (0.5 g, 1.73 mmol) in DMF

(10 mL) was added sodium acetate (0.43 g, 5.19 mmol) and the resulting mixture was heated at 67°C for lh. The resulting mixture was diluted with H O and extracted with EtOAc, washed with brine and dried (Na SO4). The solution was triturated with hexane and precipitated solid was filterd to give 0.32 g (74%). *H NMR (400 MHz, CDCI3): δ 7.58 (s, IH, aromatic), 7.84 (s, IH, aromatic), 6.2 (s, 2H, O-CH₂-O), 4.92 (s, 2H, CH₂-OAc), 2.06 (s, 3H, -CH3).

3B) Acetic acid-2-f2-amino-phenvlV2-oxo-ethvl ester

Compound of Example 3(A) (0.3 g, 1.2 mmol) was reduced following the procedure of Example 2(E) to give foam 0.24 g (92%). *H NMR (400 MHz, CDCI3): δ 6.89 (s, IH, aromatic), 6.43 (br s, 2H, -NH₂), 6.17 (s, IH, aromatic), 5.91 (s, 2H, O-CH₂-O), 5.17 (s, 2H, CH₂-OAc), 2.23 (s, 3H, -CH3).

3C) 7-Acetvl-12-hvdroxvmethvl-8-methvldioxolo T4.5-p 1 indolizino l.2-b 1 quinolin-9d lHVone

Compound of Example 1(K) (50 mg, 0.2 mmol) and compound of Example 3(B) (50 mg; 0.22 mmol) were reacted following die procedure of Example 1(L). The precipitated soUd was filtered to give ketal 45 mg (50%). *H NMR (400 MHz, CDCI3): δ 7.50 (s, IH, quinolyl), 7.30 (s, IH, quinolyl), 7.15 (s, IH pyridyl), 6.20 (s, 2H, O-CH₂-O), 5.5 (s, 2H, -CH₂Ac), 5.30 (s, 2H, 11-CH₂), 4.07 (m, 2H, ketal), 3.82 (m, 2H, ketal), 2.50 (s, 3H, -CH3), 2.20 (s, 3H, -CH3), 1.71 (s, 3H, -CH3).

The ketal above (40 mg, 0.1 mmol) was hydrolyzed following the procedure of Example 1(L) to give solid 30 mg (65%). H NMR (400 MHz, DMSOd6): δ 7.50 (s, IH, quinolyl), 7.40 (s, IH, quinolyl), 7.20 (s, IH pyridyl), 6.25 (s, 2H, O-CH₂-O), 5.4 (s, 2H, -CH₂Ac), 5.17 (s, 2H, 11-CH₂), 2.55 (s, 3H, -CH3), 2.20 (s, 3H, -CH3).

EXAMPLE 4 (±V7-π-HvdroxvethvlV8-methvldioxolo r4. -_P 1 indolizino H.2-b 1 quinolin-9f 11HV ong,

4A) (±V7-π-Hvdroxyethyl^'.-8-methyldioxolo 4.5-g 1 indolizino fl.2-b 1 quinolin- 9(llHVone. To the solution of 7-Acetyl-8-methyldioxolo [4,5-g ] indolizino [1,2-b ] quinolin-9(HH)-one (2 mg, 5μmol) in a mixture of MeOH (0.2 mL), CH₂Q₂ (0.6 mL) and THF (0.2 mL) was added a single portion of sodium borohydride (2 mg, 55 μmol). After stirring at room temperature for 1.5h, the solvent was removed in vacuum. The resulting residue was treated with 10% aqueous NH4CI (150 μL) and allowed to stand at 4^C overnight The solid which was formed was collected by filtration, washed sparingly with H₂O and dried to give yellow soUd 1.7 mg, (89%): *H NMR (400 MHz, CDCI3): δ 8.2 (s, IH, 12-quinolyl), 7.4 (s, IH, 13-quinolyl), 7.12 (s, IH, 4-quinolyl), 7.1 (s, IH, 6-pyridyl), 6.15 (s, 2H, O-CH₂-O), 5.2 (s, 2H, 11-CH₂-), 4.89 (m, IH, CHOH), 2.3 (s, 3H, Methyl) 1.5 (d, 3H, aliphatic).

EXAMPLE S' fJrV7-rifAminoacetvnoxv1ethvll-8-methvldioxolo T4.5-p 1 indolizino H.2-b 1 quinolin-9(l lHVone Hvdrotrifluroacetate.

5A) (±V7-r 1 -rrrrri.l -Dimetvlethoxv".carhonvnamino1acetvl1oxv1ethvn-8- methyldioxolo T4.5-g 1 indolizino [1.2-fr 1 quinolin-9(l lHVone. To a suspension of (t-butoxycarbonyl)glycine (2 mg, 10 μmol) in CH₂Q (2 mL) under an argon atmosphere was added 1,3-dicyclohexylcarbodiimide (2 mg, 10 μmol). After stirring at room temperature for 0.5 h, (±)-7-(l-Hydroxyethyl)-8- methyldioxolo [4,5-g ] indoUzino [1,2-b ] quinolin-9(l lH)-one.(2 mg, 5 μmol) was added, followed by 1 mg of 4-dimethylaminopyridine. The resulting mixture was stired at _oom temperature overnight, then was filtered. The filtrate was washed successively with 2.5% aqueous NaHCO3 (2 mL), 0.1 N HCI (2 mL) and H₂O (2 mL), dried (Na2SO4). The soUd residue was purified by flash column chromatography (sUica, 0-3% methanol: CH Q₂) to give the title compound 2.5 mg, (75%): *H NMR (400 MHz, CDCI3): δ 8.2 (s, IH, 12-quinolyl), 7.4 (s, IH, 13- quinolyl), 7.12 (s, IH, 4-quinolyl), 7.1 (s, IH, 6-pyridyl), 6.15 (s, 2H, O-CH₂-O), 5.89 (m, IH, CHOH), 5.2 (s, 2H, 11-CH₂-), 5.03 (br s, IH, NH),4.14-3.94 (m, 2H, CH -NCO), 2.3 (s, 3H, Methyl), 1.44 (s, 9H, t-Bu), 1.5 (d, 3H, aliphatic).

5B) f±V7-ri(Aminoacetvnoxv1ethvn-8-methvldioxolo f4.5-p 1 indolizino T1.2-b 1 quinolin-9(l lHVone Hvdrotrifluroacetate.

To a stirring suspension of (±)-7-[l-[[[[(l,l-Dimetylethoxy)carbonyl]amino] acetyl]oxy]ethyl]-8-methyldioxolo [4,5-g ] indolizino [1,2-b ] quinoUn-9(HH)-one (2.5mg, 4 μmol) in 1,3-dimethoxybenzene (2 mL) under an argon atmosphere was added trifluoroacetic acid (2 mL). After stirring for 1.5 h at room temperature, the mixture was concentrated under reduced pressure. The residue was dissolved in H₂O, extracted with Et₂O, filtered and lyophilized to afford the title compound as a pale yellow soUd 1.8 mg, (79%): *H NMR (400MHz, CD3OD) δ 8.12 (s, IH, 12- quinolyl), 7.45 (s, IH, 13-quinolyl), 7.13 (s, IH, 4-quinolyl), 7.16 (s, IH, 6-pyridyl), 6.15 (s, 2H, O-CH₂-O), 5.89 (m, IH, CHOH), 5.1 (s, 2H, 11-CH -), 4.02 (br s, 2H, CH2N), 2.25 (s, 3H, Methyl), 1.4 (d, 3H, aliphatic).

EXAMPLE ft Paremgral ornposition

To prepare a parenteral pharmaceutical composition of this invention suitable for administration by injection, 100 mg of a water soluble salt of a compound of Formula I is mixed with 10 ml of 0.9% sterile saline, and the mixture is incorporated into a dosage unit form suitable for administration by injection.

EXAMPLE 7 Oral Composition To prepare an oral pharmaceutical composition of this invention, 100 mg of a compound of Formula I is mixed with 750 mg of lactose, and the mixture is incorporated into an oral dosage unit form, such as a hard gelatin capsule, which is suitable for oral administration.

Claims

We claim:

1. A method for treating viral infections comprising administering to an infected host in need thereof an effective amount of a compound of Formula I, or a pharmaceuticaUy acceptable salt thereof, alone or in combination with a carrier, diluent or excipient

wherein:

R is =O, -OH, and OR¹;

R¹ is OCOR⁴, or OP(O)(OH)R5 wherein:

R3 is -H or lower alkyl;

R⁴ is -CR³R⁶R⁷;

-(CH₂)_nCH₂R7 _{(where n=}o_₃).

-(CH₂)_nCH₂COOH (where n=0-3);

-NR9R10_;

-NH(CH₂)_nCH₂R7 (where n = 1-3); and

-NH(CH₂)_nCH₂COOH (where n = 0-3);

R5 is OH or CH₂NH₂;

R6 is H or the side chain of any naturally occuring α-amino acid; R⁷ is NR⁹R¹⁰»

' ' where

X is any pharmaceutically acceptable anion;

R8 is lower alkyl;

R⁹ and R*0 are independently selected from the group consisting of -H, -Ci-6 alkyl, and R⁹ and R O taken together to form a 5-7 membered saturated heterocycUc ring containing the nitrogen on which R⁹ and R 10 are substituted; and R¹ ! is -CH₂R¹², wherein:

-N 0, -N NCH_j. -OH R¹² is -N(CH₃)₂ ^ ' ^ ^/

2. The method of claim 1 wherein said compound is selected from the group consisting of:

7-Acetyl-8-meΛyldioxolo[4,5-g]indolizino[l,2-b]quinoUn-9(llH)-one; (±)-7-(l -Hydroxyethyl)-8-methyldioxolo[4,5-^]indolizino[ 1 ,2-b]quinolin- 9(ll//)-one;

(±)-7-[l(Aminoacetyl)oxy]ethyl]-8-methyldioxolo[4,5-g]indolizino[l,2- b]quinoUn-9(l lHVone hydrotrifluracetate;

7-Acetyl-12-dimethylaminomethyl-8-methyldioxolo [4,5-g] indoUzino [l,2-b]quinoUn-9(HΗ)-one; and

7-Acetyl-12-hydroxymethyl-8-methyldioxolo [4,5-g] indolizino [1,2-b] quinoUn-9(l lH)-one.

3. The method of claim 2 wherein said compound is 7-acetyl-8- methyldioxolo[4,5g]indolizino[ 1 ,2-b]quinoUn-9( 1 l )-one.

4. The method of claim 2 wherein said compound is 7-acetyl- 12- dimethylaminomethyl-8-methyldioxolo [4,5-g] indoUzino [ 1 ,2-b]quinolin-9( 11ΗV one.

5. A compound of formula I, or a pharmaceutically acceptable salt thereof,

wherein:

R is =O, -OH, and OR¹

R¹ is OCOR⁴, or OP(O)(OH)R⁵ wherein:

R3 is -H or lower alkyl;

R⁴ is -CR³R⁶R⁷;

-(CH₂)_nCH₂R⁷ (where n=0-3);

-(CH₂)_nCH₂COOH (where n=0-3);

-O(CH )_nCH₂COOH (where n = 0-3);

-NR9R10_;

-NH(CH₂)_nCH₂R7 (where n = 1-3); and

-NH(CH₂)_nCH₂COOH (where n = 0-3);

R5 is OH or CH₂NH₂;

R6 is H or the side chain of any naturally occuring α-amino acid;

where X is any pharmaceuticaUy acceptable anion;

, -0 N — ^f-0 N ' , where

X is any pharmaceuticaUy acceptable anion;

R8 is lower alkyl;

R⁹ and R*0 are independently selected from the group consisting of -H, -Ci-6 alkyl, and R⁹ and R¹^ taken together to form a 5-7 membered saturated heterocyclic ring containing the nitrogen on which R⁹ and R*0 are substituted; and

R¹¹ is -CH₂R¹², wherein:

/ \ / \

-N 0, -N NCH₃, -OH

R¹² is -N(CH3)₂ ^ ^

6. The compound of claim 5 wherein said compound is selected from the group consisting of: 7-Acetyl-8-methyldioxolo[4,5-g]indolizino[l,2-b]quinoUn-9(l l /)-one;

(±)-7-(l-Hydroxyethyl)-8-methyldioxolo[4,5-g]indolizino[l,2-b]quinolin- 9(llH)-one;

(±)-7-[l(Aminoacetyl)oxy]ethyl]-8-methyldioxolo[4,5-g]indolizino[l,2- b]quinoUn-9(HH)-one hydrotrifluracetate; 7-Acetyl-12-dimethylaminomethyl-8-methyldioxolo [4,5-g] indoUzino

[l,2-b]quinoUn-9(HH)-one; and

7-Acetyl-12-hydroxymethyl-8-methyldioxolo [4,5-g] indolizino [1,2-b] quinolin-9( 1 lH)-one.

7. The compound of claim 6 wherein said compound is 7-acetyl-8- methyldioxolo[4,5g]indolizino[l,2-b]quinoUn-9(llH)-one.

8. The compound of claim 6 wherein said compound is 7-acetyl- 12- dimethylaminomethyl-8-methyldioxolo [4,5-g] indoUzino [l,2-b]quinolin-9(HΗ)- one.

9. A formulation comprising a compound of claim 5 in admixture with a carrier or excipient

10. The formulation of claim 9 wherein said carrier or excipient is a pharmaceuticaUy acceptable carrier or excipient.

11. The method of claim 1 wherein the viral infection is caused by a herpesvirus.

12. The method of claim 11 wherein said virus is herpes simplex type 1 and said infected host is a mammal.

13. The method of claim 11 wherein said virus is herpes simplex type 2 and said infected host is a mammal.

14. The method of claim 1 wherein said viral infection is caused by cytomegalovirus and said infected host is a mammal.

15. The method of claim 1 wherein said viral infection is caused by variceUa zoster virus and said infected host is a mammal.