| 1. |
- Alogheli, Hiba
(författare)
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Computational Studies of Macrocycles and Molecular Modeling of Hepatitis C Virus NS3 Protease Inhibitors
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Computational tools are utilized in the drug discovery process to discover, design, and optimize new therapeutics. One important approach is structure-based drug design which relies on knowledge about the 3D structure of the biological target. The first part of this work focuses on applying structure-based drug design for binding mode prediction of HCV NS3 protease inhibitors. The NS3 protease is a challenging target from a computational perspective as it contains an extended binding site. Binding mode predictions were performed for various classes of new acyclic and macrocyclic HCV NS3 protease inhibitors and was used in the design of new inhibitors. None of the synthetized inhibitors have been co-crystallized yet, which has made the evaluation of the suggested binding mode predictions challenging.Macrocycles are an interesting compound class in drug discovery due to their unique structural architecture, which can enable access to new chemical space. Macrocycles can successfully modulate difficult therapeutic targets, as exemplified in the development of protease inhibitors. Furthermore they can improve drug-like properties, such as cell permeability and bioavailability. The second part of this thesis focuses on macrocycles from a computational point of view. A data set of 47 clinically relevant macrocycles was compiled and used in these studies. First, two different docking protocols rigid docking of pre-generated conformers and flexible docking in Glide were evaluated and compared. The results showed that flexible docking in Glide was sufficient for docking of macrocycles with respect to accuracy and speed.The aim of the second study was to evaluate and compare the performance of the more general conformational analysis tools, MCMM and MTLMOD, with the recently developed macrocycle-specialized conformational sampling tools, Prime-MCS and MMBS. In most cases, the general conformational analysis tools (with enhanced parameter settings) performed equally well as compared to the macrocycle-specialized conformational sampling techniques. However, MMBS was superior at locating the global energy minimum conformation.Finally, calculation of the conformational energy penalty of protein-bound macrocycles was performed. The macrocycle data set was complemented with linear analogues that are similar either with respect to physicochemical properties or 2D fingerprints. The conformational energy penalties of these linear analogues were calculated and compared to the conformational energy penalties of the macrocycles. The complete data set of macrocycles and non-macrocycles in this study differ from previously published work addressing conformational energy penalties, since it covers a more extended area of chemical space. Furthermore, there was a weak correlation between the calculated conformational energy penalties and the flexibility of the structures.
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| 2. |
- Svensson, Fredrik, 1987-
(författare)
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Computational Methods in Medicinal Chemistry : Mechanistic Investigations and Virtual Screening Development
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Computational methods have become an integral part of drug development and can help bring new and better drugs to the market faster. The process of predicting the biological activity of large compound collections is known as virtual screening, and has been instrumental in the development of several drugs today in the market. Computational methods can also be used to elucidate the energies associated with chemical reactivity and predict how to improve a synthetic protocol. These two applications of computational medicinal chemistry is the focus of this thesis.In the first part of this work, quantum mechanics has been used to probe the energy surface of palladium(II)-catalyzed decarboxylative reactions in order to gain a better understating of these systems (paper I-III). These studies have mapped the reaction pathways and been able to make accurate predictions that were verified experimentally.The other focus of this work has been to develop virtual screening methodology. Our first study in the area (paper IV) investigated if the results from several virtual screening methods could be combined using data fusion techniques in order to get a more consistent result and better performance. The study showed that the results obtained from data fusion were more consistent than the results from any single method. The data fusion methods also for several target had a better performance than any of the included single methods.Next, we developed a dataset suitable for evaluating the performance of virtual screening methods when applied to large compound collection as a replacement or complement for high throughput screening (paper V). This is the first benchmark dataset of its kind.Finally, a method for using computationally derived reaction coordinates as basis for virtual screening was developed. The aim was to find inhibitors that resemble key steps in the mechanism (paper VI). This initial proof of concept study managed to locate several known and one previously not reported reaction mimetics against insulin regulated amino peptidase.
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| 3. |
- Lindh, Martin, 1981-
(författare)
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Computational Modelling in Drug Discovery : Application of Structure-Based Drug Design, Conformal Prediction and Evaluation of Virtual Screening
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Structure-based drug design and virtual screening are areas of computational medicinal chemistry that use 3D models of target proteins. It is important to develop better methods in this field with the aim of increasing the speed and quality of early stage drug discovery.The first part of this thesis focuses on the application of structure-based drug design in the search for inhibitors for the protein 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR), one of the enzymes in the DOXP/MEP synthetic pathway. This pathway is found in many bacteria (such as Mycobacterium tuberculosis) and in the parasite Plasmodium falciparum.In order to evaluate and improve current virtual screening methods, a benchmarking data set was constructed using publically available high-throughput screening data. The exercise highlighted a number of problems with current data sets as well as with the use of publically available high-throughput screening data. We hope this work will help guide further development of well designed benchmarking data sets for virtual screening methods.Conformal prediction is a new method in the computer-aided drug design toolbox that gives the prediction range at a specified level of confidence for each compound. To demonstrate the versatility and applicability of this method we derived models of skin permeability using two different machine learning methods; random forest and support vector machines.
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| 4. |
- Åkerbladh, Linda
(författare)
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Palladium(0)-Catalysed Carbonylative Multicomponent Reactions : Synthesis of Heterocycles and the Application of Quinolinyl Pyrimidines as Enzyme Inhibitors
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Palladium-catalysed carbonylative multicomponent reactions have proven useful for the synthesis of structurally diverse compounds. Carbon monoxide serves as an atom-efficient, one-carbon building block, which allows for further structural elaboration of the carbonyl compound. By varying the components of the carbonylative multicomponent reaction, considerable product diversity can readily be attained. However, due to the reluctance to use toxic CO gas, considerable efforts have been directed at exploring non-gaseous approaches. The work described in this thesis has mainly focused on the development of palladium(0)-catalysed, carbonylative multicomponent synthetic methodology, using the non-gaseous CO source molybdenum hexacarbonyl, in the synthesis of heterocycles and other biologically relevant functional groups.The first part of this work describes the development of a non-gaseous carbonylative Sonogashira cross-coupling of bifunctional ortho-iodoanilines and terminal alkynes. Where 4-quinolones were synthesised via a carbonylation/cyclisation sequence. Using a similar synthetic strategy, three different N-cyanobenzamide intermediates were prepared by palladium-catalysed carbonylative couplings of various aryl halides and bromides and cyanamide. The formed intermediates provided a basis for further chemical transformations. First, ortho-iodoanilines were carbonylatively coupled with cyanamide and subsequently cyclised to yield heterocyclic 2-aminoquinazolinones. Next, building on those findings, the same synthetic strategy was applied to ortho-halophenols to provide a highly convenient domino carbonylation/cyclisation method for the preparation of benzoxazinones. The developed method was used to evaluate the efficiency of various non-gaseous CO sources. Third, the palladium-catalysed carbonylative synthesis of N-cyanobenzamides, was used to produce biologically relevant N-acylguanidines with considerable product diversity. Finally, one of the developed carbonylative methodologies was used in the preparation of potential NDH-2 inhibitors based on a quinolinyl pyrimidine scaffold. The prepared compounds were biologically evaluated in terms of inhibition of oxidoreductase NDH-2 and antibacterial activity on Gram-negative bacteria, S. aureus and Mtb. The biological evaluation revealed that some of the quinolinyl pyrimidines exerted inhibitory activity on the NDH-2 enzyme and possessed antibacterial properties.The work described in this thesis has been devoted to the development of non-gaseous one-pot, multicomponent carbonylation/cyclisation and carbonylation/amination reactions. The described methods offer highly attractive synthetic strategies that can be of great value to synthetic and medicinal chemists.
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