<p>Since 1981, HIV/AIDS has affected over 70 million individuals worldwide. Due to the incorporation of Combination Antiretroviral Therapy (cART), this deadly virus has now become a manageable chronic illness with a reduction in mortality and morbidity rates. Combination therapy targets multiple stages of the HIV replication cycle including fusion, entry, reverse transcription, integration, and maturation. The HIV-1 protease enzyme is responsible for cleavage and processing of viral polyproteins into mature enzymes and is a common therapeutic target for inhibition of HIV. To date, there have been many protease inhibitors approved by the FDA and introduced into the market. However, mutations within the protease enzyme has rendered some of these inhibitors ineffective. This has led to an ever-growing need to develop novel protease inhibitors to combat drug resistance through mutations. Described herein is the design, synthesis, and biological evaluation of HIV-1 protease inhibitors featuring a novel hexahydropyrrolofuran (HPF) bicyclic scaffold as a P₂ ligand to target binding interactions with Asp29 and Asp30. The HPF ligand provides a molecular handle that allows for further structure-activity discoveries within the enzyme. The HIV-1 protease inhibitors discussed feature carbamate, carboxamide, and sulfonamide derivatives which displayed good to excellent activity.</p>

<p>HIV-1 protease inhibitors are important in the most frequently used regimen for the treatment of HIV/AIDS, the highly active antiretroviral therapy (HAART). For patients with access to this treatment, an HIV infection is no longer lethal, but rather a manageable, chronic infection. However, the HIV-1 protease inhibitors are generally associated with serious shortcomings such as adverse events, development of drug resistance and poor pharmacokinetic properties. Most of the approved inhibitors suffer from high protein binding, rapid metabolism and/or low membrane permeability. </p><p>In this project, novel HIV-1 protease inhibitors comprising a rarely used tertiary alcohol in the transition-state mimic were designed, synthesized and evaluated. The rationale behind the design was to achieve ‘masking’ of the tertiary alcohol by for example, intramolecular hydrogen bonding, which was believed could enhance transcellular transport. </p><p>A reliable synthetic protocol was developed and a series of highly potent inhibitors was obtained exhibiting excellent membrane permeation properties in a Caco-2 cell assay. However, the cellular antiviral potencies of these compounds were low. In an attempt to improve the anti-HIV activity, microwave-accelerated, palladium-catalyzed cross-coupling reactions and aminocarbonylation of aryl bromide precursors were employed to produce P1'-extended test compounds. Inhibitors demonstrating up to six times higher antiviral effect were obtained, the best derivatives having para 3- or 4-pyridyl elongations in P1'.</p><p>Fast metabolic degradation was observed in liver microsome homogenate, which is believed, at least partly, to be attributable to benzylic oxidation of the indanol P2 group of the inhibitors. To enable facile variation of the P2 side chain a new synthetic route was developed using an enantiomerically pure, benzyl-substituted epoxy carboxylic acid as the key intermediate. Cyclic and amino-acid-residue-derived P2 groups were evaluated, and inhibitors equipotent to the series containing an indanol moiety were produced.</p>

HIV-1 protease inhibitors are important in the most frequently used regimen for the treatment of HIV/AIDS, the highly active antiretroviral therapy (HAART). For patients with access to this treatment, an HIV infection is no longer lethal, but rather a manageable, chronic infection. However, the HIV-1 protease inhibitors are generally associated with serious shortcomings such as adverse events, development of drug resistance and poor pharmacokinetic properties. Most of the approved inhibitors suffer from high protein binding, rapid metabolism and/or low membrane permeability. In this project, novel HIV-1 protease inhibitors comprising a rarely used tertiary alcohol in the transition-state mimic were designed, synthesized and evaluated. The rationale behind the design was to achieve ‘masking’ of the tertiary alcohol by for example, intramolecular hydrogen bonding, which was believed could enhance transcellular transport. A reliable synthetic protocol was developed and a series of highly potent inhibitors was obtained exhibiting excellent membrane permeation properties in a Caco-2 cell assay. However, the cellular antiviral potencies of these compounds were low. In an attempt to improve the anti-HIV activity, microwave-accelerated, palladium-catalyzed cross-coupling reactions and aminocarbonylation of aryl bromide precursors were employed to produce P1'-extended test compounds. Inhibitors demonstrating up to six times higher antiviral effect were obtained, the best derivatives having para 3- or 4-pyridyl elongations in P1'. Fast metabolic degradation was observed in liver microsome homogenate, which is believed, at least partly, to be attributable to benzylic oxidation of the indanol P2 group of the inhibitors. To enable facile variation of the P2 side chain a new synthetic route was developed using an enantiomerically pure, benzyl-substituted epoxy carboxylic acid as the key intermediate. Cyclic and amino-acid-residue-derived P2 groups were evaluated, and inhibitors equipotent to the series containing an indanol moiety were produced.

<p>In medicinal chemistry, there is a constant need for new preparative methods, both to make the synthesis process more effective, and to increase the accessibility to a wide variety of compounds. A number of different approaches can be used to attain these goals. Transition metal catalysis is generally performed under mild conditions, providing both regio- and chemoselective reactions. Thus, it offers an attractive means of preparation of complex drug candidates. Two additional methodologies used to increase the preparative efficiency are one-pot protocols and controlled microwave heating. One-pot and multi-component reactions are less time consuming than step-by-step reactions, and microwave heating has been used to considerably shorten the reaction times. </p><p>This thesis describes a new palladium-catalyzed, one-pot reaction producing racemic acetal-protected 3-hydroxy-1-indanones from ethylene glycol vinyl ether and triflates of salicylic aldehydes. The triflates were prepared using controlled microwave heating. The reaction sequence starts with a regioselective internal Heck coupling, followed by an annulation cascade. By including secondary amines in the reaction mixture, the reaction was further developed into a three-component reaction delivering racemic acetal-protected 3-amino-1-indanones. This new method was utilized for the synthesis of primary, secondary and tertiary aminoindanones. Finally, by using enantiopure t-butyl sulfinyl imines, derived from salicylic aldehyde triflates and ethylene glycol vinyl ether as starting materials in a closely related type of palladium coupling–annulation sequence, a stereoselective protocol providing enantiomerically pure 3-amino-1-indanones was developed. To demonstrate an application in medicinal chemistry, the enantiopure 3-amino-1-indanones were incorporated as P2 and/or P2´ substituents into active HIV-1 protease inhibitors.</p>

In medicinal chemistry, there is a constant need for new preparative methods, both to make the synthesis process more effective, and to increase the accessibility to a wide variety of compounds. A number of different approaches can be used to attain these goals. Transition metal catalysis is generally performed under mild conditions, providing both regio- and chemoselective reactions. Thus, it offers an attractive means of preparation of complex drug candidates. Two additional methodologies used to increase the preparative efficiency are one-pot protocols and controlled microwave heating. One-pot and multi-component reactions are less time consuming than step-by-step reactions, and microwave heating has been used to considerably shorten the reaction times. This thesis describes a new palladium-catalyzed, one-pot reaction producing racemic acetal-protected 3-hydroxy-1-indanones from ethylene glycol vinyl ether and triflates of salicylic aldehydes. The triflates were prepared using controlled microwave heating. The reaction sequence starts with a regioselective internal Heck coupling, followed by an annulation cascade. By including secondary amines in the reaction mixture, the reaction was further developed into a three-component reaction delivering racemic acetal-protected 3-amino-1-indanones. This new method was utilized for the synthesis of primary, secondary and tertiary aminoindanones. Finally, by using enantiopure t-butyl sulfinyl imines, derived from salicylic aldehyde triflates and ethylene glycol vinyl ether as starting materials in a closely related type of palladium coupling–annulation sequence, a stereoselective protocol providing enantiomerically pure 3-amino-1-indanones was developed. To demonstrate an application in medicinal chemistry, the enantiopure 3-amino-1-indanones were incorporated as P2 and/or P2´ substituents into active HIV-1 protease inhibitors.