Integrase inhibitors

Abstract

Tricyclic compounds of formulae I-III, protected intermediates thereof, and methods for inhibition of HIV-integrase are disclosed.

Description

FIELD OF THE INVENTION[0001]The invention relates generally to compounds having antiviral activity, and more specifically, compounds having HIV-integrase inhibitory properties.BACKGROUND OF THE INVENTION[0002]Human immunodeficiency virus (HIV) infection and related diseases are a major public health problem worldwide. A virally encoded integrase protein mediates specific incorporation and integration of viral DNA into the host genome. Integration is necessary for viral replication. Accordingly, inhibition of HIV integrase is an important therapeutic pursuit for treatment of HIV infection of the related diseases.[0003]Human immunodeficiency virus type 1 (HIV-1) encodes three enzymes which are required for viral replication: reverse transcriptase, protease, and integrase. Although drugs targeting reverse transcriptase and protease are in wide use and have shown effectiveness, particularly when employed in combination, toxicity and development of resistant strains have limited their us...

AI Technical Summary

Benefits of technology

[0102]This invention also includes a method of increasing cellular accumulation, bioavailability or retention of drug compounds, thus improving their therapeutic and diagnostic value, by administering a phosphonate prodrug form of a compound of the invention.

[0109]“Prodrug moiety” means a labile functional group which separates from the active inhibitory compound during metabolism, systemically, inside a cell, by hydrolysis, enzymatic cleavage, or by some other process (Bundgaard, H., “Design and Application of Prodrugs” in Textbook of Drug Design and Development (1991), P. Krogsgaard-Larsen and H. Bundgaard, Eds. Harwood Academic Publishers, pp. 113-191). Enzymes which are capable of an enzymatic activation mechanism with the prodrug compounds of the invention include, but are not limited to, amidases, esterases, microbial enzymes, phospholipases, cholinesterases, and phosphases. Prodrug moieties can serve to enhance solubility, absorption and lipophilicity to optimize drug delivery, bioavailability and efficacy. A “prodrug” is thus a covalently modified analog of a therapeutically-active compound.

[0110]Exemplary prodrug moieties include the hydrolytically sensitive or labile acyloxymethyl esters —CH2C(═O)R20 and acyloxymethyl carbonates —CH2OC(═O)OR20 where R20 is C1-C6 alkyl, C1-C6 substituted alkyl, C6-C20 aryl or C6-C20 substituted aryl. The acyloxyalkyl ester was first used as a prodrug strategy for carboxylic acids and then applied to phosphates and phosphonates by Farquhar et al., (1983) J. Pharm. Sci. 72: 324; also U.S. Pat. Nos. 4,816,570, 4,968,788, 5,663,159 and 5,792,756, which are all incorporated by reference. In certain compounds of the invention, a prodrug moiety is part of a phosphonate group. Subsequently, the acyloxyalkyl ester was used to deliver phosphonic acids across cell membranes and to enhance oral bioavailability. A close variant of the acyloxyalkyl ester, the alkoxycarbonyloxyalkyl ester (carbonate), may also enhance oral bioavailability as a prodrug moiety in the compounds of the invention. An exemplary acyloxymethyl ester is pivaloyloxymethoxy, (POM)-CH2C(═O)C(CH3)3. An exemplary acyloxymethyl carbonate prodrug moiety is pivaloyloxymethylcarbonate (POC) —CH2C(═O)OC(CH3)3.

[0112]Aryl esters of phosphorus groups, especially phenyl esters, are reported to enhance oral bioavailability (DeLambert et al (1994) J. Med. Chem. 37: 498). Phenyl esters containing a carboxylic ester ortho to the phosphate have also been described (Khamnei and Torrence, (1996) J. Med. Chem. 39:4109-4115). Benzyl esters are reported to generate the parent phosphonic acid. In some cases, substituents at the ortho-orpara-position may accelerate the hydrolysis. Benzyl analogs with an acylated phenol or an alkylated phenol may generate the phenolic compound through the action of enzymes, e.g. esterases, oxidases, etc., which in turn undergoes cleavage at the benzylic C—O bond to generate the phosphoric acid and the quinone methide intermediate. Examples of this class of prodrugs are described by Mitchell et al., (1992) J. Chem. Soc. Perkin Trans. 12345; Brook et al., WO 91 / 19721. Still other benzylic prodrugs have been described containing a carboxylic ester-containing group attached to the benzylic methylene (Glazier et al., WO 91 / 19721). Thio-containing prodrugs are reported to be useful for the intracellular delivery of phosphonate drugs. These proesters contain an ethylthio group in which the thiol group is either esterified with an acyl group or combined with another thiol group to form a disulfide. Deesterification or reduction of the disulfide generates the free thio intermediate which subsequently breaks down to the phosphoric acid and episulfide (Puech et al., (1993) Antiviral Res., 22: 155-174; Benzaria et al., (1996) J. Med. Chem. 39: 4958). Cyclic phosphonate esters have also been described as prodrugs of phosphorus-containing compounds (Erion et al., U.S. Pat. No. 6,312,662).

Problems solved by technology

Human immunodeficiency virus (HIV) infection and related diseases are a major public health problem worldwide.

Although drugs targeting reverse transcriptase and protease are in wide use and have shown effectiveness, particularly when employed in combination, toxicity and development of resistant strains have limited their usefulness (Palella, et al N. Engl. J. Med.

Although numerous agents potently inhibit 3′-P and ST in extracellular assays that employ recombinant integrase and viral long-terminal-repeat oligonucleotide sequences, often such inhibitors lack inhibitory potency when assayed using fully assembled preintegration complexes or fail to show antiviral effects against HIV-infected cells (Pommier, et al Adv.

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