Methods for inhibiting the transmission of HIV using topically applied substituted 6-benzyl-4-oxopyrimidines

This application claims priority to provisional application serial No. 60/249,532, filed Nov. 17, 2000.

The present invention is compounds, methods, compositions, and devices for preventing infection by sexually transmitted HIV.

The 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. Since it emerged as a public health threat in the early 1980's, efforts to control or eradicate the disease have focused principally on options for treating the disease after an individual has already become infected.

The use of condoms provides a substantial degree of protection against transmission of HIV infections during sexual intercourse. However, the use of condoms is not 100% effective against the transmission of HIV. Moreover, couples often do not use condoms. A topical composition that could be inserted into the vagina or rectum by a foam, gel, sponge or other form, or which could be topically applied to the male genitalia, would in many cases be preferred over condoms. Moreover, the prophylactic effectiveness of condoms could be improved by including a suitable microbicide in the lubricant coated on the exterior of the condom. However, to date little progress has been made to develop an effective topical composition against the transmission of HIV.

Most work to develop topical HIV prophylactic compositions has focused on the use of surfactants and buffers, such as the over-the-counter product nonoxynol-9. Surfactants and detergents disrupt microbial and sperm membranes by lysis and emulsification. Surfactant-containing creams and gels have the advantage of being very broad in their killing ability, and thus can kill the HIV virus and viruses associated with other sexually transmitted diseases. The use of surfactants and buffers is, however, substantially limited by the damage they can cause to cell membranes. In the vagina, nonoxynol-9 has been shown to thin vaginal walls. In the rectum, nonoxynol-9 can cause rectum walls to slough off.

Other virusidal compositions being investigated for use as HIV virusides include carageenan and other large sulfated polysaccharides that stick to viral envelopes and possibly shield cell membranes. Philips D M, “Of Mice and Men—Assaying Vaginal Virusides,” Virusides 2000, Mar. 13-16, 2000, Alexandria Va., page 12, abstract A20. Monoclonal antibodies have also been proposed as HIV prophylactics, and some antibodies have shown a promising degree of protection. (Mascola J et al., “Role of IgG Antibody in Protection against Vaginal Transmission of an HIV-1/SIV Chimeric Virus,” Virusides 2000, Mar. 13-16, 2000, Alexandria Va., page 7, abstract A10; Watanabe, M., Boyson, J. E., Lord, C. I. and Letvin, N. L. “Chimpanzees Immunized with Recombinant Soluble CD4 Develop Anti-self CD4 Antibody Responses with Anti-human Immunodeficiency Virus Activity”, Proc. Natl. Acad. Sci. U.S.A., 89, 5103-5107 (1992); and Perno, C. -F., Baseler, M. W., Broder, S. and Yarchoan, R., “Infection of Monocytes by Human Immunodeficiency Virus Type 1 Blocked by Inhibitors of CD4-gp120 Binding, Even in the Presence of Enhancing Antibodies”, J. Exp. Med., 171, 1043-1056 (1990)).

International application published as WO 00/03998 to P. LaColla and M. Artico disclosed substituted 6-benzyl-4-oxopyrimidines useful in the treatment of HIV.

Elise A. Sudbeck, Chen Mao, Rakesh Vig, T. K. Venkatachalam, Lisa Tuel-Ahlgren, and Fatih M. Uckun disclose various dihydroalkoxybenzyloxopyrimidine derivatives shown to be effective against HIV, which were designed based on structure analysis of potent nonnucleoside inhibitors of the human immunodeficiency virus reverse transcriptase.

Scientists have recently reported several biological discoveries that improve our understanding of how HIV enters an organism following sexual contact, which could lead to prophylactic substances that interfere with HIV's interaction with its target cells. These discoveries revolve generally around T lymphocytes, monocytes/macrophages and dendritic cells, suggesting that CD4 cell receptors are engaged in the process of virus transmission (Parr, M. B. and Parr, E. L., “Langerhans Cells and T lymphocyte Subsets in the Murine Vagina and Cervix”, Biology of Reproduction, 44, 491-498 (1991); Pope, M. et al., “Conjugates of Dendritic Cells and Memory T Lymphocytes from Skin Facilitate Productive Infection With HIV-1”, Cell, 78, 389-398 (1994); and Wira, C. R. and Rossoll, R. M., “Antigen-presenting Cells in the Female Reproductive Tract: Influence of Sex Hormones on Antigen Presentation in the Vagina”, Immunology, 84, 505-508 (1995)). Geijtenbeek TBH et al., for example, recently reported that HIV tightly binds the DC—SIGN molecule on the surface of dendritic cells, through the gp120 HIV envelope protein. When the dendritic cells present microbial antigens to CD4+ T helper cells to stimulate an immune response, the dendritic cell inadvertently transfers the HIV to the CD4+ T cells, thereby advancing the progression of the infection.

Some have postulated, based upon these discoveries, that prophylactics can be designed that block the interaction between DC—SIGN and gp120. Similarly, DC4 and chemokine receptor blockers could be designed and administered to prevent the transfer of HIV from the dendritic cells to the CD4+ T cells. However, methods that rely on the specific interaction of HIV and human cells are limited, because the infection pathway has not been fully defined and may be diverse. (Miller, C. J. et al., “Genital Mucosal Transmission of Simian Immunodeficiency Virus: Animal Model for Heterosexual Transmission of Human Immunodeficiency Virus”, J. Virol., 63, 4277-4284 (1989); Phillips, D. M. and Bourinbaiar, A. S., “Mechanism of HIV Spread from Lymphocytes to Epithelia”, Virology, 186, 261-273 (1992); Phillips, D. M., Tan, X., Pearce-Pratt, R. and Zacharopoulos, V. R., “An Assay for HIV Infection of Cultured Human Cervix-derived Cells”, J. Virol. Methods, 52, 1-13 (1995); Ho, J. L. et al., “Neutrophils from Human Immunodeficiency Virus (HIV)-SeronegatiVe Donors Induce HIV Replication from HIV-infected Patients Mononuclear Cells and Cell lines”: An In Vitro Model of HIV Transmission Facilitated by Chlamydia Trachomatis., “J. Exp. Med., 181, 1493-1505 (1995); and Braathen, L. R. & Mork, C. in “HIV infection of Skin Langerhans Cells”, In: Skin Langerhans (dendritic) cells in virus infections and AIDS (ed. Becker, Y.) 131-139 (Kluwer Academic Publishers, Boston, (1991)).

Efforts by researchers to develop an HIV vaccine have also not yet been successful. Siegel et al. reported that vaccination with inactivated SIV did not protect African Green monkeys against infection with the homologous virus notwithstanding a strong immune response to SIV. (Siegel, F., Kurth, R., and Norley, S., (1995), “Neither Whole Inactivated Virus Immunogen nor Passive Immunoglobulin Transfer Protects Against SIV Infection in the African Green Monkey Natural Host”, J. AIDS, 8, 217-226).

Therefore, there remains a need for an effective topical prophylactic against the sexual transmission of HIV. It is an object of the invention, therefore, to provide topical prophylactic compositions against the sexual transmission of HIV, methods for using such compositions, and devices that deliver such compositions.

It is another object of the invention to provide compounds that have extended activity against the HIV virus.

It is another object of this invention to provide a topical composition that can be applied to the areas of skin and mucus epithelia at highest risk for exchanging HIV pathogens. Formulations of such compositions can be based upon existing topical compositions used as lubricants and contraceptives, which are often present as lotions or gels, or coated to the exterior of condoms.

It is another object of this invention to create new, long-term prophylactic methods for women based upon existing contraceptive devices, including sustained release devices to be inserted in the vagina (intra-vaginal devices such as sponges and cervical caps).

It is still another object of this invention to provide suppositories and intra-vaginal or rectal pills that can be inserted into the vagina or rectum in order to release one or more anti-HIV agents at a predetermined rate.

Yet another object of the invention is to deliver, along with the anti-HIV agent, agents against other things from which the user desires protection, such as sperm, toxins, and/or STD pathogens.

The invention provides compounds, compositions and methods for prophylactically inhibiting the spread of AIDS. The compounds of the present invention display inhibition of HIV replication, and do so for a prolonged period of time, which renders them useful in prophylactic applications, wherein the frequency or duration of use are not always predictable. The compounds are also useful in prophylactic applications because they inhibit the HIV virus upon contact at very low concentrations, before the virus has infected its host and begun replication. Non-nucleoside reverse transcriptase inhibitors (“NNRTI”) have proven especially invaluable in this type of application.

Thus, in one embodiment, the invention provides a method for inhibiting sexual transmission of HIV comprising topically applying to the skin or epithelial tissue of a human a composition comprising a non-nucleoside reverse transcriptase inhibitor (“NNRTI”) that is able to inhibit viral replication for periods exceeding 12, 24 or even 36 days, at concentrations below even 10 μM.

In one embodiment the NNRTI is a dihydro-alkyloxy-benzyl-oxopyrimidine (DABO). This class of compounds is capable of inhibiting HIV multiplication targeting reverse transcriptase without bioactivation. Preferred DABOs include compounds of formula (A):

as herein defined.

In another embodiment the invention provides a topical composition in the form of a cream, lotion, gel, or foam, comprising a dihydro-alkyloxy-benzyl-oxopyrimidine.

In still another embodiment the invention provides a composition in the form of an intra-vaginal or intra-rectal pill or suppository comprising a dihydro-alkyloxy-benzyl-oxopyrimidine.

A still further embodiment provides a device for inhibiting the sexual transmission of HIV comprising: (a) a barrier structure for insertion into the vaginal cavity, and (b) a composition comprising a dihydro-alkyloxy-benzyl-oxopyrimidine.

Still a further embodiment provides dihydro-alkyloxy-benzyl-oxopyrimidines defined by the foregoing structure.

FIG. 1 is a three dimensional line graph showing the levels of viral p24 in cell culture supernatants treated with the specified concentrations of MC 1220.

FIG. 2 is a three dimensional line graph showing the levels of viral p24 in cell culture supernatants treated with the specified concentrations of Nevirapine.

FIG. 3 is a three dimensional line graph showing the levels of viral p24 in cell culture supernatants treated with the specified concentrations of MC-1047.

In one aspect the invention provides a composition and method for inhibiting sexual transmission of HIV comprising topically applying to the skin or epithelial tissue of a human a composition comprising a non-nucleoside reverse transcriptase inhibitor (“NNRTI”) that is able to inhibit viral replication for periods exceeding 12, 24, or even 36 days. In separate embodiments, the composition is able to inhibit viral replication for such prolonged periods at concentrations as low as 50, 35, 20, 10 or 5 μM. The ability of a compound to inhibit viral replication is preferably evaluated by the HIV-1 p24 antigen enzyme-linked immunosorbent assay. Suitable ELISA kits are available, for example, from Abbott Laboratories. Particular methods for their use are set forth in the examples herein. The ability of a non-nucleotide compound to inhibit reverse transcriptase can also be assessed by the methods set forth in the examples hereof.

The composition is preferably applied topically to any skin or epithelial tissue that comes in contact with bodily fluids of a sexual partner during sexual intercourse or foreplay, including the vaginal endothelium, the rectal endothelium or the male genitalia. As used herein, the term “topical application” refers to something that is applied to and spread across the surface of the skin or a mucous membrane (by contrast, “systemic” administration refers to a drug or other compound that is ingested orally or injected beneath the skin). A condom lubricant or other genital lubricant is a topical agent as that term is used herein.

In one particular embodiment the NNRTI is a dihydro-alkyloxy-benzyl-oxo-pyrimidine, as defined further herein.

Preferred compositions can take several forms. Thus, in one embodiment the composition is in the form of a cream, lotion, gel, or foam that is applied to the affected skin or epithelial cavity, and preferably spread over the entire skin or epithelial surface which is at risk of contact with bodily fluids. Such formulations, which are suitable for vaginal or rectal administration, may be present as aqueous or oily suspensions, solutions or emulsions (liquid formulations) containing in addition to the active ingredient, such carriers as are known in the art to be appropriate. For “stand-alone” lubricants (i.e., lubricants that are not pre-packaged with condoms), gels and similar aqueous formulations are generally preferred, for various reasons (both scientific and economic) known to those skilled in the art. These formulations are useful to protect not only against sexual transmission of HIV, but also to prevent infection of a baby during passage through the birth canal. Thus the vaginal administration can take place prior to sexual intercourse, during sexual intercourse, and immediately prior to childbirth.

One method of applying an anti-viral lubricant to the genitals, for the purposes disclosed herein, involves removing a small quantity (such as a teaspoon, or several milliliters) of a gel, cream, ointment, emulsion, or similar formulation from a plastic or metallic tube, jar, or similar container, or from a sealed plastic, metallic or other packet containing a single dose of such composition, and spreading the composition across the surface of the penis immediately before intercourse. Alternate methods of emplacement include: (1) spreading the composition upon accessible surfaces inside the vagina or rectum shortly before intercourse; and (2) emplacing a condom, diaphragm, or similar device, which has already been coated or otherwise contacted with an anti-viral lubricant, upon the penis or inside the vagina. In a preferred embodiment, any of these methods of spreading an anti-viral lubricant across the surfaces of the genitals causes the lubricant to coat and remain in contact with the genital and epithelial surfaces throughout intercourse.

In one embodiment the compositions are used in conjunction with condoms, to enhance the risk-reducing effectiveness of condoms and provide maximum protection for users. The composition can either be coated onto condoms during manufacture, and enclosed within conventional watertight plastic or foil packages that contain one condom per package, or it can be manually applied by a user to either the inside or the outside of a condom, immediately before use.

As used herein, “condom” refers to a barrier device which is used to provide a watertight physical barrier between male and female genitalia during sexual intercourse, and which is removed after intercourse. This term includes conventional condoms that cover the penis; it also includes so-called “female condoms” which are inserted into the vaginal cavity prior to intercourse. The term “condom” does not include diaphragms, cervical caps or other barrier devices that cover only a portion of the epithelial membranes inside the vaginal cavity. Preferably, condoms should be made of latex or a synthetic plastic material such as polyurethane, since these provide a high degree of protection against viruses.

In another embodiment the composition is in the form of an intra-vaginal pill, an intra-rectal pill, or a suppository. The suppository or pill should be inserted into the vaginal or rectal cavity in a manner that permits the suppository or pill, as it dissolves or erodes, to coat the vaginal or rectal walls with a prophylactic layer of the anti-HIV agent.

In still another embodiment the composition is topically applied by release from an intravaginal device. Devices such as vaginal rings, vaginal sponges, diaphrams, cervical caps, female condoms, and the like can be readily adapted to release the composition into the vaginal cavity after insertion.

Compositions used in the methods of this invention may also comprise other active agents, such as another agent to prevent HIV infection, and agents that protect individuals from conception and other sexually transmitted diseases. Thus, in another embodiment the compositions used in this invention further comprise a second anti-HIV agent, a virucide effective against viral infections other than HIV, and/or a spermicide.

In one particular embodiment, the composition contains nonoxynol, a widely-used spermicidal surfactant. The resulting composition could be regarded as a “bi-functional” composition, since it would have two active agents that provide two different desired functions, in a relatively inert carrier liquid; the nonoxynol would provide a spermicidal contraceptive agent, and the DABO would provide anti-viral properties. The nonoxynol is likely to cause some level of irritation, in at least some users; this is a regrettable but is a well-known side effect of spermicidal surfactants such as nonoxynol and octoxynol, which attack and destroy the lipid bilayer membranes that surround sperm cells and other mammalian cells.

The compositions used in this invention may also contain a lubricant that facilitates application of the composition to the desired areas of skin and epithelial tissue, and reduces friction during sexual intercourse. In the case of a pill or suppository, the lubricant can be applied to the exterior of the dosage form to facilitate insertion.

In still another embodiment the invention provides a device for inhibiting the sexual transmission of HIV comprising (a) a barrier structure for insertion into the vaginal cavity, and (b) a composition comprising a dihydro-alkyloxy-benzyl-oxopyrimidine. As mentioned above, preferred devices which act as barrier structures, and which can be adapted to apply anti-HIV agent, include the vaginal sponge, diaphram, cervical cap, or condom (male or female).

The methods, compositions and devices of this invention can be adapted generally to release active agent in a time sensitive manner that best corresponds to the timing of sexual activity. When topically applied as a lotion or gel, the compositions are preferably applied immediately prior to sexual activity. Other modes of application, such as devices and suppositories, can be designed to release active agent over a prolonged period of time, at a predetermined rate, depending upon the needs of the consumer.

Dihydro-alkyloxy-benzyl-oxopyrimidines

The dihydro-alkyloxy-benzyl-oxopyrimidines of this invention are preferably defined by formula A described below, combinations thereof, or pharmaceutically acceptable salts thereof:

A principle embodiment is defined wherein:

X is —O, —CH 2 , —CHK 1 (wherein K 1 is —H, —C 1-4 alkyl, —C 3-6 Cycloalkyl), —S, —NK 2 (wherein K 2 is —H, —C 1-4 alkyl, —C 3-6 cycloalkyl, or a bond when X—R is nitro), -aryl, or -arylalkyl;

R is —H, —C 1-4 alkyl (optionally containing one or more of heteroatoms selected from O, S, and N), —C 3-6 cycloalkyl (optionally containing one or more of heteroatoms selected from O, S, N), -aryl, -arylakl, heterocycle, oxo, thio, or a primary amine;

Y is —H, —C 1-4 alkyl or —C 3-6 cycloalkyl;

Z is —H, —C 1-4 alkyl or —C 3-6 cycloalkyl;

R 1 is —H, —C 1-4 alkyl, -halogen, —NO 2 , ΔOW (wherein W is —H, —CH 3 , aryl), or —SW (wherein W is —H, —CH 3 , -aryl);

R 2 is —H, —C 1-4 alkyl, -halogen, —NO 2 , —OW (wherein W is —H, —CH 3 , -aryl); or —SW (wherein W is —H, —CH 3 , -aryl);

R 3 is —H, —C 1-4 alkyl, -halogen, —NO 2 , —OW (wherein W is —H, —CH 3 , -aryl); or —SW (wherein W is —H, —CH 3 , -aryl);

R 4 is —H, —C 1-4 alkyl, -halogen, —NO 2 , —OW (wherein W is —H, —CH 3 , -aryl); or —SW (wherein W is —H, —CH 3 ,-aryl); and

R 5 is —H, —C 1-4 alkyl, -halogen, —NO 2 , —OW (wherein W is —H, —CH 3 , -aryl), or —SW (wherein W is —H, —CH 3 , -aryl).

A first principal class of 13 subembodiments are defined when:

1. Y is —C 1-4 alkyl, Z is —C 1-4 alkyl, and X, R, R 1 , R 2 , R 3 , R 4 and R 5 are as defined above in the principal embodiment;

2. Y is methyl, Z is methyl, and X, R, R 1 , R 2 , R 3 , R 4 and R 5 are as defined above in the principal embodiment;

3. R 1 and R 5 are halogen, and Y, Z, X, R, R 2 , R 3 and R 4 are as defined above in the principal embodiment;

4. R 1 and R 5 are fluorine, and Y, Z, X, R, R 2 , R 3 and R 4 are as defined above in the principal embodiment;

5. R 2 , R 3 and R 4 are hydrogen, and Y, Z, X, R, R 1 and R 5 are as defined above in the principal embodiment;

6. Y is —C 1-4 alkyl, Z is —C 1-4 alkyl, R 1 and R 5 are halogen, and X, R, R 2 , R 3 and R 4 are as defined above in the principal embodiment;

7. Y is methyl, Z is methyl, R 1 and R 5 are fluorine, and X, R, R 2 , R 3 and R 4 are as defined above in the principal embodiment;

8. Y is —C 1-4 alkyl, Z is —C 1-4 alkyl, R 2 , R 3 and R 4 are hydrogen, and X, R, R 1 and R 5 are as defined above in the principal embodiment;

9. Y is methyl, Z is methyl, R 2 , R 3 and R 4 are hydrogen, and X, R, R 1 and R 5 are as defined above in the principal embodiment;

10. R 1 and R 5 are halogen, R 2 , R 3 and R 4 are hydrogen, and X, R, Y and Z are as defined above in the principal embodiment;

11. R 1 and R 5 are fluorine, R 2 , R 3 and R 4 are hydrogen, and X, R, Y and Z are as defined above in the principal embodiment;

12. Y is —C 1-4 alkyl, Z is —C 14 alkyl, R 1 and R 5 are halogen, R 2 , R 3 and R 4 are hydrogen, and X and R are as defined above in the principal embodiment; and

13. Y is methyl, Z is methyl, R 1 and R 5 are fluorine, R 2 , R 3 and R 4 are hydrogen, and X and R are as defined above in the principal embodiment.

A second principal class of subembodiments are defined when:

1. —X is NK, and Y, Z, R, R 1 , R 2 , R 3 , R 4 and R 5 are as defined in any one of the first class of thirteen subembodiments;

2. —X is NK, R is H, and Y, Z, X, R 1 , R 2 , R 3 , R 4 and R 5 are as defined in any one of the first class of thirteen subembodiments;

3. —X—R is —N-Me 2 , and Y, Z, X, R 1 , R 2 , R 3 , R 4 and R 5 are as defined in any one of the first class of thirteen subembodiments;

4. —X—R is —NH-cPe (cyclic pentane), and Y, Z, X, R 1 , R 2 , R 3 , R 4 and R 5 are as defined in any one of the first class of thirteen subembodiments;

5. —X—R is —N═O, and Y, Z, X, R, R 1 , R 2 , R 3 , R 4 and R 5 are as defined in any one of the first class of thirteen subembodiments;

6. —X is S, and Y, Z, X, R, R 1 , R 2 , R 3 , R 4 and R 5 are as defined in any one of the first class of thirteen subembodiments;

7. —X—R is —S-Me, and Y, Z, X, R 1 , R 2 , R 3 , R 4 and R 5 are as defined in any one of the first class of thirteen subembodiments;

8. —X—R is —S-MeSMe, and Y, Z, X, R 1 , R 2 , R 3 , R 4 and R 5 are as defined in any one of the first class of thirteen subembodiments; and

9. —X—R is —S-cPe, and Y, Z, X, R 1 , R 2 , R 3 , R 4 and R 5 are as defined in any one of the first class of thirteen subembodiments.

Preferred species of dihydro-alkyloxy-benzyl-oxopyrimidines are defined when:

1. —X—R is —N-Me 2 , Y is methyl, Z is methyl, R 1 and R 1 are fluorine, and R 2 , R 3 and R 4 are hydrogen (MC 1220);

2. —X—R is —NH-cPe (cyclic pentane), Y is methyl, Z is methyl, R 1 and R 5 are fluorine, and R 2 , R 3 and R 4 are hydrogen (MC 1129);

3. —X—R is —N=O, Y is methyl, Z is methyl, R 1 and R 1 are fluorine, and R 2 , R 3 and R 4 are hydrogen (MC 1237);

4. —X—R is —S-Me, Y is methyl, Z is methyl, R and R 1 are fluorine, and R 2 , R 3 , and R 4 are hydrogen (MC 1060);

5. —X—R is —S-MeSMe, Y is methyl, Z is methyl, R 1 and R 5 are fluorine, and R 2 , R 3 and R 4 are hydrogen (MC 1214); and

6. —X—R is —S-cPe, Y is methyl, Z is methyl, R 1 and R 5 are fluorine, and R 2 , R 3 , and R 4 are hydrogen (MC 1047).

Other preferred species of dihydro-alkyloxy-benzyl-oxopyrimidines are those listed in table 1 and table 2.

In another embodiment the invention provides compounds defined by the foregoing species, embodiments, and subembodiments.

Stereoisomerism and Polymorphism

The compounds of the present invention may have asymmetric centers and occur as racemates, racemic mixtures, individual diastereomers or enantiomers, with all isomeric forms being included in the present invention. Compounds of the present invention having a chiral center may exist in and be isolated in optically active and racemic forms. Some compounds may exhibit polymorphism. The present invention encompasses racemic, optically-active, polymorphic, or stereoisomeric form, or mixtures thereof, of a compound of the invention, which possess the useful properties described herein. The optically active forms can be prepared by, for example, resolution of the racemic form by recrystallization techniques, by synthesis from optically-active starting materials, by chiral synthesis, or by chromatographic separation using a chiral stationary phase or by enzymatic resolution.

Opitically active forms of the compounds can be prepared using any method known in the art, including by resolution of the racemic form by recrystallization techniques, by synthesis from optically-active starting materials, by chiral synthesis, or by chromatographic separation using a chiral stationary phase.

Examples of methods to obtain optically active materials include at least the following.

i) physical separation of crystals—a technique whereby macroscopic crystals of the individual enantiomers are manually separated. This technique can be used if crystals of the separate enantiomers exist, i.e., the material is a conglomerate, and the crystals are visually distinct;

ii) simultaneous crystallization—a technique whereby the individual enantiomers are separately crystallized from a solution of the racemate, possible only if the latter is a conglomerate in the solid state;

iii) enzymatic resolutions—a technique whereby partial or complete separation of a racemate by virtue of differing rates of reaction for the enantiomers with an enzyme;

iv) enzymatic asymmetric synthesis—a synthetic technique whereby at least one step of the synthesis uses an enzymatic reaction to obtain an enantiomerically pure or enriched synthetic precursor of the desired enantiomer;

v) chemical asymmetric synthesis—a synthetic technique whereby the desired enantiomer is synthesized from an achiral precursor under conditions that produce asymmetry (i.e., chirality) in the product, which may be achieved using chiral catalysts or chiral auxiliaries;

vi) diastereomer separations—a technique whereby a racemic compound is reacted with an enantiomerically pure reagent (the chiral auxiliary) that converts the individual enantiomers to diastereomers. The resulting diastereomers are then separated by chromatography or crystallization by virtue of their now more distinct structural differences and the chiral auxiliary later removed to obtain the desired enantiomer;

vii) first- and second-order asymmetric transformations—a technique whereby diastereomers from the racemate equilibrate to yield a preponderance in solution of the diastereomer from the desired enantiomer or where preferential crystallization of the diastereomer from the desired enantiomer perturbs the equilibrium such that eventually in principle all the material is converted to the crystalline diastereomer from the desired enantiomer. The desired enantiomer is then released from the diastereomer;

viii) kinetic resolutions—this technique refers to the achievement of partial or complete resolution of a racemate (or of a further resolution of a partially resolved compound) by virtue of unequal reaction rates of the enantiomers with a chiral, non-racemic reagent or catalyst under kinetic conditions;

ix) enantiospecific synthesis from non-racemic precursors—a synthetic technique whereby the desired enantiomer is obtained from non-chiral starting materials and where the stereochemical integrity is not or is only minimally compromised over the course of the synthesis;

x) chiral liquid chromatography—a technique whereby the enantiomers of a racemate are separated in a liquid mobile phase by virtue of their differing interactions with a stationary phase (including via chiral HPLC). The stationary phase can be made of chiral material or the mobile phase can contain an additional chiral material to provoke the differing interactions;

xi) chiral gas chromatography—a technique whereby the racemate is volatilized and enantiomers are separated by virtue of their differing interactions in the gaseous mobile phase with a column containing a fixed non-racemic chiral adsorbent phase;

xii) extraction with chiral solvents—a technique whereby the enantiomers are separated by virtue of preferential dissolution of one enantiomer into a particular chiral solvent;

xiii) transport across chiral membranes—a technique whereby a racemate is placed in contact with a thin membrane barrier. The barrier typically separates two miscible fluids, one containing the racemate, and a driving force such as concentration or pressure differential causes preferential transport across the membrane barrier. Separation occurs as a result of the non-racemic chiral nature of the membrane that allows only one enantiomer of the racemate to pass through.

Chiral chromatography, including simulated moving bed chromatography, is used in one embodiment. A wide variety of chiral stationary phases are commercially available.

When any variable occurs more than one time in any constituent or in formula A of this invention, 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.

As used herein except where noted, “alkyl” is intended to include both branched- and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms; “Halogen” or “Hal” as used herein, means fluoro, chloro, bromo and iodo.

As used herein, with exceptions as noted, “aryl” is intended to mean any stable monocyclic, bicyclic or tricyclic carbon ring of up to 7 members in each ring, wherein at least one ring is aromatic as defined by the Huckel 4n+2 rule. Examples of aryl ring systems include phenyl, naphthyl, tetrahydronaphthyl, biphenyl.

The term heterocycle or heterocyclic, as used herein except where noted represents a stable 5- to 7-membered monocyclic or stable 8- to 11-membered bicyclic heterocyclic ring which is either saturated or unsaturated, and which consists of carbon atoms and from one to three heteroatoms selected from the group consisting of N, O and S; and wherein the nitrogen and sulfur heteroatoms may optionally be oxidized, and the nitrogen heteroatom may optionally be quatemized, and including any bicyclic group in which any of the above-defined heterocyclic rings is fused to a benzene ring. The heterocyclic ring may be attached at any heteroatom or carbon atom which results in the creation of a stable structure.

The pharmaceutically-acceptable salts of the compounds of this invention that are capable of salt formation (in the form of water- or oil- soluble or dispersible products) include the conventional non-toxic salts or the quaternary ammonium salts of these compounds, which are formed, e.g., from inorganic or organic acids or bases.

Secondary Antiviral Constituents

The compositions of this invention may optionally contain a second anti-HIV agent. Exemplary agents include AZT, D4T, FTC (2′,3′-dideoxy-3′-thia-5-fluorocytidine); 3TC (Epivir, Glaxo Wellcome, Inc.), AZDU (3′-Azido-2′,3′-dideoxyuridine); 141W94 (amprenavir, GlaxoWellcome, Inc.); Viramune (nevirapine), Rescriptor (delavirdine); or DMP-266 (efavirenz). Other examples of anti-HIV agents include DDI, DDC, Delaviridine, β-LddA, β-L-3′-azido-d5FC, carbovir, acyclovir, interferon, stavudine, CS-92 (3′-azido-2′,3′-dideoxy-5-methyl-cytidine), 3′-azido nucleosides, and β-D-dioxolane nucleosides such as β-D-dioxolanylguanine (DXG), β-D-dioxolanyl-2,6-diarninopurine (DAPD), and β-D-dioxolanyl-6-chloropurine (ACP).

Preferred protease inhibitors include indinavir ({1(1,S,2R),5(S)}-2,3,5-trideoxy-N-(2,3-dihydro-2-hydroxy-1H-inden-1-yl)-5-{2-{{(1,1-dimethylethyl)amino}carbonyl}-4-(3-pyridinylmethyl)-1-piperazinyl}-2-(phenylmethyl)-D-erythro-pentoamide sulfate; Merck), nelfinavir (Agouron), ritonavir (Abbot), and saquinavir (Invirase; Roche).

Nonliniting examples of other compounds that can be administered in combination or alternation with the compounds of the present invention to augment the properties of the drug on administration include abacavir: (1S,4R)-4-{2-amino-6-cyclopropyl-amino)-9H-purin-9-yl}-2-cyclopentene-1-methanol succinate (1592U89, a carbovir analog; Glaxo Wellcome); zidovudine: AZT, 3′-azido-3′-deoxythymidine (Glaxo Wellcome); BILA 1906: N-{1S-{{{3-{2S-{(1,1-dimethylethyl)amino}carbonyl}-4R-}-3-pyridinylmethyl)-thio}-1-piperidinyl}-2R-hydroxy-1S-(phenyhnethyl)propyl}amino}carbonyl}-2-methylpropyl}-2-quinolinecarboxamide (Bio Mega/Boehringer-Ingelheim); BILA 2185: N-(1,1-dimethylethyl)-1-{2S-{{2-2,6-dimethylphenoxy)-1-oxoethyl}amino}-2R-hydroxy-4-phenylbutyl}4R-pyridinylthio)-2-piperidinecarboxamide (Bio Mega/Boehringer-Ingelheim); BM+51.0836:triazoloisoindolinone derivative; BMS 186,318: aminodiol derivative HIV-1 protease inhibitor (Bristol-Myers-Squibb); d4API: 9-{2,5-dihydro-5-(phosphonomethoxy)-2-furanel}adenine (Gilead); stavudine: d4T, 2′,3′-didehydro-3′-deoxythymidine (Bristol-Myers-Squibb); efavirenz: DMP-266, a 1,4-dihydro-2H-3,1-benzoxazin-2-one; HBY097: S-4-isopropoxycarbonyl-6-methoxy-3-(methylthiomethyl)-3,4-dihydroquinoxalin-2(1H)-thione; HEPT: 1-{(2-hydroxyethoxy)methyl}6-(phenylthio)-thymine; KNI-272: (2S,3S)-3-amino-2-hydroxy-4-phenylbutyric acid-containing tripeptide; L-697,593; 5-ethyl-6-methyl-3-(2-phthalimido-ethyl)pyridin-2(1H)-one; L-735,524: hydroxy-aminopentane amide HIV-1 protease inhibitor (Merck); L-697,661: 3-{ {(−4,7-dichloro-1,3-benzoxazol-2-yl)methyl}amino}-5-ethyl-6-methylpyridin-2(1H)-one; L-FDDC: (−)-β-L-5-fluoro-2′,3′-dideoxycytidine; L-FDOC: (−)-β-L-5-fluoro-dioxolane cytosine; 6-benzyl-1-ethoxymethyl-5-isopropyluracil (I-EBU; Triangle/Mitsubishi); nevirapine: 11-cyclopropyl-5,11-dihydro-4-methyl-6H-dipyridol{3,2-b:2′,3′-e}diazepin-6-one (Boehringer-Ingelheim); PFA: phosphonoformate (foscarnet; Astra); PMEA: 9-(2-phosphonylmethoxyethyl) adenine (Gilead); PMPA: (R)-9-(2-phosphonyl-methoxypropyl)adenine (Gilead); Ro 31-8959: hydroxythethylamine derivative HIV-1 protease inhibitor (Roche); RPI-3121: peptidyl protease inhibitor, 1-{(3s)-3-(n-alpha-benzyloxycarbonyl)-1-asparginyl)-amino-2-hydroxy-4-phenylbutyryl}-n-tert-butyl-1-proline amide; 2720: 6-chloro-3,3-dimethyl-4-(isopropenyloxycarbonyl)-3,4-dihydro-quinoxalin-2(1H)thione; SC-52151: hydroxyethylurea isostere protease inhibitor (Searle); SC-55389A: hydroxyethyl-urea isostere protease inhibitor (Searle); TIBO R82150: (+)-(5S)-4,5,6,7-tetrahydro-5-methyl-6-(3-methyl-2-butenyl)imidazo {4,5,1jk}-{1,4}-benzodiazepin-2(1H)-thione (Janssen); TIBO 82913: (+)-(5S)-4,5,6,7,-tetrahydro-9-chloro-5-methyl-6-(3-methyl-2-butenyl)imidazo {4,5,1jk}-{1,4}benzodiazepin-2(1H)-thione (Janssen); TSAO-m3T: {2′,5 ′-bis-O-(tert-butyldimethylsilyl)-3 ′-spiro-5 ′-(4′-amino-1,′2′-oxathiole-2′,2′-dioxide)}-β-D-pentofuranosyl-N3-methylthymine; U90152: 1-{3-{(1-methylethyl)-amino}2-pyridinyl}-4-{{5-{(methylsulphonyl)-amino}-11H-indol-2yl}carbonyl}piperazine; UC: thiocarboxanilide derivatives (Uniroyal); UC-781 ═N-{4-chloro-3-(3-methyl-2-butenyloxy)phenyl}-2-methyl-3-furancarbothioamide; UC-82 ═N-{4-chloro-3-(3-methyl-2-butenyloxy)phenyl}-2-methyl-3-thiophenecarbothioamide; VB 11,328: hydroxyethylsulphonamide protease inhibitor (Vertex); VX-478: amprenavir, 141W94, hydroxyethylsulphonamide protease inhibitor (Vertex/Glaxo Wellcome); XM 323: cyclic urea protease inhibitor (Dupont Merck), delaviridine (Pharmacia Upjohn), famciclovir, gancyclovir, and penciclovir.

In one embodiment, a compound of the present invention is administered in combination with LG1350, which has the following structure.

Synthetic Methods

Preparation of compounds of formula (1) can be achieved by the general procedures listed below.

Anhydrous pyridine (400 mmoles, 32.5 ml) was added with stirring under nitrogen atmosphere into an ice-cooled solution of 2,2-dimethyl-1,3-dioxane-4,6-dione (Meldrurm's acid) (165 mmoles, 23.75 g) in anhydrous dichloromethane (50 ml). The resulting solution was treated, over a 2 h period at 0° C. under nitrogen atmosphere, with a solution of crude arylacetyl chloride in anhydrous dichloromethane (50 ml). Arylacetyl chloride was prepared before use by refluxing the proper arylacetic acid (43.2 mmoles) with thionyl chloride (21.3 ml) under nitrogen atmosphere for 2 h. Then, the mixture was stirred for 2 h at room temperature, poured into crushed ice and treated with 2N HCl (100 ml). The organic layer was separated and the aqueous solution was extracted twice with dichloromethane (25 ml). The organic phase and the extracts were combined, washed with brine, dried and evaporated. The solid residue was dissolved in anhydrous methanol (250 ml) and the solution was refluxed for 20 h. After cooling, metal sodium (0.16 g-atoms, 3.68 g) was carefully added and the mixture was stirred until dissolution was complete. Alkyl halide (160 mmoles) was dropped into the solution and the resulting mixture was heated at reflux for 4-12 h. After cooling, the solvent was removed and the residue treated with water (200 ml) and extracted with chloroform (3×100 ml). The organic layer was washed with brine (2×100 ml), dried and evaporated to give the desired compound (3), which was purified by passing through a silica gel column (chloroform as eluent).

In the above reaction, arylacetic acid (Scheme “A”) or arylacetyl chloride can be replaced with the corresponding 1-arylacetylimidazolide (Scheme “B”) or with arylacetylethoxycarbonylanhydride, whereas the Meldrum's acid can be replaced with ethyl acetylacetate, ethyl alkylmalonate or ethyl alkylmalonate potassium salt, to give the proper ethyl arylacetylalkylacetates in high yields.

Preparation Of Compounds (I) (in Scheme B) with X═O (See Scheme A).

The proper methyl arylacetylalkylacetate (2) (10 mmoles) in methanol (50 ml) was added to a well-stirred suspension of O-methylisourea hydrogen sulphate (15 mmoles, 2.58 g) and calcium hydroxide (16 mmoles, 1.18 g) in water (50 ml). The resulting mixture was stirred at room temperature for 72 h, then concentrated, made acid (pH 5) with 0.5N acetic acid and extracted with ethyl acetate (3×50 ml). The combined organic extracts were washed with brine (100 ml), dried and evaporated to dryness. The residue was purified by crystallization from the proper solvent yielding pure 5-alkyl-6-benzyl-3,4-dihydro-2-methoxypyrimidin-4-one (4). This compound was then refluxed with the proper potassium alkoxide (100 mmoles of potassium metal in 20-30 ml of alcohol freshly distilled on sodium metal) under nitrogen atmosphere until starting material disappeared at the TLC control. After cooling, the mixture was concentrated, made acid (pH 5) with 0.5N acetic acid and extracted with ethyl acetate (3×50 ml). The combined extracts were washed once with brine (100 ml), dried and evaporated to give the required 2-alkoxy-5-alkyl-6-benzyl-3,4-dihydropyrimidin-4-one derivative (A), which was recrystallized from a suitable solvent or purified by column chromatography (silica gel; ethyl acetate:chloroform 1:1). Physical and chemical data of representative compounds of the invention are reported in table 1; cytotoxicity and anti-HIV-1 activity data are reported in table 2.

The proper ethyl arylacetylalkylacetate (31.5 mmoles) was successively added to a stirred solution of sodium metal (0.063 g-atoms) in 50 mL of absolute ethanol (50 ml) and thiourea (43 mmoles). The mixture was heated while stirring at reflux for 5 h. After cooling, the solvent was distilled in vacuo at 40-50° C. until dryness and the residue was dissolved in water (200 mL) and made acid (pH 5) with 0.5N acetic acid. The resulting precipitate (the crude 2-thiouracil derivative) was filtered under reduced pressure, washed with diethyl ether, vacuum dried at 80° C. for 12 h and then crystallized from the proper solvent (I).

Then, according to method A, iodomethane (8 mmoles, 1.13 g) was added to a suspension containing the proper 2-thiouracil derivative (4 mmoles) in anhydrous N,N-dimethylformamide (2 ml), and the resulting mixture was stirred at room temperature until the starting material disappeared at the TLC control (silica gel; n-hexane: ethyl acetate: methanol 12:3:1). Then the reaction content was poured on cold water (100 mL) and extracted with ethyl acetate (3×50 ml). The organic layers were collected, washed with a sodium thiosulfate solution (100 ml), brine (3×50 ml), dried and evaporated to furnish the crude 5-alkyl-6-benzyl-3,4-dihydro-2-methylthiopyrimidin-4-one (5) as a solid purified by crystallization.

Alternatively, according to methods B and C, potassium carbonate (4.2 mmoles) and the proper alkyl halide (4.4 mmoles) were added to a suspension containing 2-thiouracil derivative (4 mmoles) in anhydrous N,N-dimethylformamide (2 ml). The resulting mixture was stirred at room temperature (method B) or at 80° C. (method C) until starting material disappeared at the TLC control (silica gel; n-hexane:ethyl acetate:methanol 12:3:1). Then the reaction content was poured on cold water (200 mL), made acid (pH 5) with 0.5N acetic acid and extracted with ethyl acetate (3×50 ml). The organic layers were collected, washed with a sodium thiosulfate solution (100 ml), brine (100 ml), dried and evaporated to furnish 5-alkyl-6-benzyl-3,4-dihydro-2-methylthiopyrimidin-4-ones (6) and (7) as crude material which was then purified by column chromatography on silica gel (eluent: n-hexane:ethyl acetate:methanol 12:3:1) followed by crystallization. Physical and chemical data of representative compounds of the invention are reported in table 1. Cytotoxicity and anti-HIV-1 activity in vitro are reported in table 2.

Title derivatives were prepared according to the procedure described for the synthesis of compounds with X═S (I), using ethyl arylacetylalkylacetates and guanidine {2-amino-6-benzylpyrimidin-4-ones (8)} as starting materials. 2-Alkylaminoderivatives (9) were synthesized by heating the previously reported 5-alkyl-6-benzyl-3,4-dihydro-2-methylthio pyrimidin-4-ones with 20-30 ml of proper amine in a sealed tube at 170° C. for 24 h. Physical and chemical data of some compounds (9) are reported in table 1. Cytotoxicity and anti-HIV-1 activity in vitro are reported in table 2.

Assay Procedures for Results Reported in Tables 1 and 2

Compounds. Compounds were solubilized in DMSO at 200 mM and then diluted into culture medium.

Cells and viruses. MT-4, C8166,H9/IIIB and CEM cells were grown at 37° C. in a 5% CO 2 atmosphere in RPMI 1640 medium, supplemented with 10% fetal calf serum (FCS), 100 IU/mL penicillin and 100 μg/mL streptomycin. Cell cultures were checked periodically for the absence of mycoplasma contamination with a MycoTect Kit (Gibco). Human immunodeficiency virus type-I (HIV-1, III B strain) was obtained from supernatants of persistently infected H9/III B cells. HIV-1 stock solution had a titres of 4.5×10 6 50% cell culture infectious dose (CCID 50 )/ml.

HIV Titration. Titration of HIV was performed in C8166 cells by the standard limiting dilution method (dilution 1:2, four replica wells per dilution) in 96-well plates. The infectious virus titre was determined by light microscope scoring of cytopathicity after 4 days of incubation and the virus titres were expressed as CCID 50 /mL.

Anti-HIV Assays. Activity of the compounds against HIV-1 and HIV-2 multiplication in acutely infected cells was based on the inhibition of virus-induced cytopathicity in MT-4 and C8166 cells, respectively. Briefly, 50 μL of culture medium containing 1×10 4 cells were added to each well of flat-bottom microtiter trays containing 50 μl of culture medium with or without various concentrations of the test compounds. Then 20 μL of an HIV suspension containing 100 CCID 50 were added. After a 4-day incubation at 37° C., the number of viable cells was determined by the 3-(4,5-dimethylthiazol-1-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Cytotoxicity of the compounds was evaluated in parallel with their antiviral activity. It was based on the viability of mock-infected cells, as monitored by the MTT method.

RT Assays. Assays were performed as follows. Briefly, purified rRT was assayed for its RNA-dependent polymerase-associated activity in a 50 μL volume containing: 50 mM TrisHCl (pH 7.8), 80 mM KCI1, 6 mM MgCl2, 1 mM DTT, 0.1 mg/mL BSA, 0.3 OD 260 unit/mL template:primer {poly(rC)-oligo(dG)12-18} and 10 μM { 3 H}dGTP (1 Ci/mmol). After incubation for 30 min at 37° C., the samples were spotted on glass fiber filters (Whatman GF/A), and the acid-insoluble radioactivity was determined.