Yes / Tetrahydroisoquinoline (THIQ) is a key structural component in many biologically active molecules including natural products and synthetic pharmaceuticals. Here, we report on the use of transition-metal mediated [2 + 2 + 2] cyclotrimerisation of alkynes to generate tricyclic THIQs with potential to selectively inhibit AKR1C3. / Fundação para a Ciência, a Tecnologia (PhD studentship ARNS SFRH/BD/46871/2008), EPSRC (RCUK Academic Fellowship HMS), UniTO grant Ricerca Locale 2015 (grant number LOLM_RILO_17_01) and Fondazione Cassa di Risparmio di Torino (grant BOSD_CRT_17_2).

The thesis is composed of three chapters. The aim of this thesis is to apply the novel dirhodium perfluorobutyrate-catalyzed intramolecular aromatic C-H insertion methodology to the enantioselective total synthesis of praziquantel and synthetic model studies on ecteinascidin 743, which belongs to the important tetrahydroisoquinoline family. The first introductory chapter deals with the biological significance and previous synthetic methodologies. Our novel methodology is based on dirhodium perfluorobutyrate-catalyzed intromolecular aromatic C-H insertion reaction, which is crucial in the pivotal carbon-carbon bond formation when constructing isoquinolone moiety, which is ubiquitous in numerous natural products of significant biological and pharmacological activities. The second chapter takes on the first enantioselective total synthesis of praziquantel, an antihelmintic drug. Praziquantel is used worldwide to treat schistosomiasis, which has tremendous impact on the global fight on this disease affecting 150 million people. We believe this is the first asymmetric total synthesis to date, which is distinct from previous racemic syntheses reported. We also shed light on the mechanistic aspect of this key reaction to rationalize the superb regioselectivity and stereoselectivity achieved. The third chapter explores the synthetic model studies on ecteinascidin 743, a tetrahydroisoquinolone family natural product with significant antitumor and antimicrobial activities. Several different synthetic routes were attempted, including the N-Methyl and the N-Boc routes, and the results achieved contributed significantly to our final synthetic plan of the target molecule.

No description available.

Tetrahydroisoquinoline alkaloids are a class of structurally complex natural products and a huge number of its natural product widely exist in nature which, from the discovery has been more than a century, it compounds with high anti-tumor activity, antibacterial and other physical activity, but also because of its special structure, with low oncentration of biological activity, but these alkaloids are not sold in the market mainly due to a less natural extraction, chemical synthesis method and multi-step, low yield. Therefore, we constructed a combination of tetrahydroisoquinoline alkaloids and the pyrazino [2,1-b] quinazoline-3,6-diones structure of the new compounds, which have the quinazolinone compounds which is the drug synthesis and drug activity on the bond, is also a kind of unique and widely used drug structure, and causes a lot of scientists and drug research interest and discussion, as we develop the motivation.

The tetrahydroisoquinoline alkaloids have been studied thoroughly about their biological and chemical significance over the past 30 years. These natural products show great biological activity, especially ET-743 and saframycin A, makes them promising therapeutics, while their structural complexity and particularity provide challenging synthetic targets. These alkaloids or derivatives show interesting biological activity, but the most important drawback as potential market therapeutics is the minute amount of them available from nature, and the synthetic methods published are inconvenient, difficult, and hard to handle. Herein is described our researches about the tetrahydroisoquinoline alkaloids. Chapter 1 describes relevant background related to the biological significance of these alkaloids, and the currently synthetic studies toward these natural products. Chapter 2 describes our design and synthesis of the analogues based on the anticancer mechanism of the tetrahydroisoquinoline alkaloids, and the biological activities of these analogues. Chapter 3 describes a rapid synthetic route for the common structure of the bis-tetrahydroisoquinoline alkaloids via a controlled mono-Pictet-Spengler cyclization.

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-07-10T13:59:53Z No. of bitstreams: 1 arquivototal.pdf: 4398305 bytes, checksum: c95cf82f72f9c0e04311709786123245 (MD5) / Made available in DSpace on 2017-07-10T13:59:53Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4398305 bytes, checksum: c95cf82f72f9c0e04311709786123245 (MD5) Previous issue date: 2016-05-27 / Alkaloids are secondary metabolites of great medical importance, covering a diverse group of nitrogen containing molecules in its structure, the number of alkaloid containing the tetrahidroisoquinolínico skeleton 1-substituted is extensive and impressive pharmacological versatility of this class arouses interest in experimental pharmacologists, the importance. This work has as objective, the synthesis of tetrahydroisoquinolines and provide material for future pharmacological studies both in-vivo and in-vitro. For the synthesis of phenyltetrahydroisoquinolinics alkaloids, benzyltetrahydroisoquinilinic and phenyltetrahydro-β-carboline the Pictet-Spengler reaction was aplicated. With the aim of expanding the pharmacological studies of the alkaloid (1-(3-dimethoxy-4-hydroxyphenyl)-7-methoxy-1,2,3,4,-tetrahydroisoquinoline (MTHP) your synthesis was repeated. 4 alkaloids were obtained, 2 phenyltetrahydroisoquinolinic (1-(3,5-dimethoxy-4-hydroxyphenyl)-7-methoxy-1,2,3,4-tetrahydroisoquinoline (73%) and 1-(2-hydroxyphenyl)-7-methoxy-1,2,3,4-tetrahydroisoquinoline (54%)), 1 phenyltetrahydro-β-carboline (1-(3,5-dimethoxy-4-hydroxyphenyl)-1,2,3,4,-tetrahydro-β-carboline (38%)) and 1 benzyltetrhydroisoquinilínic (1-(1-ethyl-3,4-metilenodioxidofenil)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (87%)). From the material available for the pharmacological MTHP tests showed low toxicity without genotoxicity, its immunomodulatory mechanism in asthma is related to regulation of TH2 profile. / Alcaloides são metabólitos secundários de grande importância medicinal, abrangendo um grupo diverso de moléculas contendo nitrogênio na sua estrutura. O número de alcaloides que contém o esqueleto tetrahidroisoquinolínico 1-substituído é extenso e a impressionante versatilidade farmacológica desta classe desperta o interesse nos farmacologistas experimentais. Visto a importância dos alcaloides isoquinolínicos, o nosso trabalho tem como objetivo a síntese de derivados tetrahidroisoquinolínicos e fornecer material para futuros estudos farmacológicos tanto in-vivo como in-vitro. Para a síntese dos alcaloides feniltetrahidroisoquinolínicos, benziltratrahidroisoquinilínicos e feniltetrahidro-β-carbolínicos foi utilizado a reação de Pictet-Spengler. Com o objetivo de ampliar os estudos farmacológicos a respeito do alcaloide (1-(3-dimetoxi-4-hidroxifenil)-7-metoxi-1,2,3,4,-tetrahidro isoquinolina (MTHP) refizemos a sua síntese como descrito na literatura. Obtivemos 4 alcaloides, sendo 2 deles feniltetrahidroisoquinolínicos (1-(3,5-dimetoxi-4-hidroxifenil)-7-metoxi-1,2,3,4,-tetrahidro isoquinolina (73%) e 1-(2-hidroxifenil)-7-metoxi-1,2,3,4,-tetrahidro isoquinolina (54%)), 1 feniltetrahidro-β-carbolínicos (1-(3,5-dimetoxi-4-hidroxifenil)-1,2,3,4,-tetrahidro-β-carbolina (38%)) e 1 benziltratrahidroisoquinilínicos (1-(1-etil-3,4-metilenodioxidofenil)-6,7-dimetoxi-1,2,3,4,-tetrahidro isoquinolina(87%)). A partir da disponibilização de material para os testes farmacológicos do MTHP, apresentou baixa toxicidade sem genotoxicidade, seu mecanismo imunomodulador na asma está relacionado a regulação do perfil TH2.

Cette thèse est fondée sur le développement de nouvelles méthodes de criblage et d’analyse appliquées aux extraits naturels. Le premier axe de ce travail a consisté à isoler une molécule très minoritaire dans un mélange réactionnel de synthèse biomimétique en utilisant entre autre la chromatographie de partage centrifuge (CPC) en mode pH-zone refining. Nous avons pu isoler la nitrarine avec un rendement de 0,04% en permettant de valider le mécanisme proposé pour sa synthèse biomimétique.Le deuxième axe de ce projet est consacré à l’identification par fractionnement bioguidé, dans les graines de Mucuna pruriens (une plante de la pharmacopée traditionnelle indienne), des molécules responsables de la synergie thérapeutique antiparkinsonienne mise en évidence dans la littérature par des essais in vivo et cliniques. L’extrait hydro-alcoolique de graines de Mucuna pruriens a été fractionné par chromatographie sur colonne de gel de silice, puis les fractions obtenues ont été évaluée in vitro sur plusieurs cibles biologiques : enzymes de dégradation de la dopamine (MAO, COMT), et une enzyme de sa synthèse endogène (DDC). Nous avons développé une méthodes de détection d’une activité d’inhibition de ces enzymes par spectrométrie de masse. À partir des fractions identifiées comme étant actives, nous avons isolé et identifié une vingtaine de molécules, parmi lesquelles une dizaine sont nouvellement décrites. Il a été nécessaire de synthétiser certaines d'entre elles en raison de la quantité nécessaire aux essais biologiques. Certaines de ces molécules ont montré une activité inhibitrice intéressante sur la COMT / This thesis is based on the development of new methods of screening and analysis applied to natural extracts.The first axis of this work consisted in isolating a minoritary molecule in a reaction mixture of a biomimetic synthesis using different techniques including centrifugal partition chromatography (CPC) in pH-zone refining mode. We were able to isolate the nitrarine with a yield of 0.04%, thus allowing to validate the proposed mechanism of its biomimetic synthesis.The second axis of this project is dedicated to the identification in the seeds of Mucuna pruriens (a plant of Indian traditional pharmacopoeia), by bioguided fractionation, the molecules responsible for the antiparkinsonian synergy demonstrated by in vivo studies and clinical trials. For this purpose, the hydroalcoholic extract of M. pruriens seeds was fractionated by chromatography on a silica gel column and the obtained fractions were evaluated in vitro on various biological targets: the dopamine-degrading enzymes (MAO, COMT) and an enzyme implicated in its endogenous synthesis (DDC). Moreover, we have developed a method to detect by mass spectrometry fractions or compounds having an inhibitory activity on these enzymes. From fractions identified as active, we isolated and identified about twenty molecules, from which a dozen are newly described. On the other hand, it was necessary to synthetize some of them due to the amount required by bioassays. Some of these molecules have shown an interesting inhibitory activity against the COMT enzyme

The tetrahydroisoquinoline (THIQ) core structure is explored as a steroidomimetic nucleus with attractive pharmaceutical properties. A library was synthesised employing Pomeranz-Fritsch, Pictet-Spengler, Bischler-Napieralski strategies yielding 77 final targets, substituted at every position, for biological evaluation. Complementary strategies overcame synthetic difficulties, sometimes yielding two products in a single cyclisation. Three compounds were initially tested against a panel of 19 nuclear receptors (NRs) and exhibited broad substitution-dependent activity. 2-(4-Chlorophenyl)-1-isopropyl-1,2,3,4-tetrahydroisoquinolin-6-ol fully inhibited every NR at 100 µM, confirming the THIQ as a lead for optimisation. Compounds were evaluated for cytotoxicity against 60 cell lines by the NCI (USA), exhibiting moderate to insignificant cytotoxicity. Three compounds showed ca. 30-90% of average growth inhibition and were selected for a five dose test. Off-target evaluation highlighted compounds with activity against glucagon-like peptide 1 secretion, calcitonin gene-related peptide receptor antagonism and with >100% inhibition against the metabotropic glutamate receptor 2. Estrogen receptor-related receptor α (ERRα), a constitutively active orphan NR, is a hormone-dependent cancer target and diethylstilboestrol (DES), a known inverse agonist, possesses similarities to THIQs. THIQs tested against ERRα revealed no general SAR rules, but showed a lower degree of efficacy in a commercial TR-FRET assay, with 1-benzyl-2-(4-chlorophenyl)-4-methyl-1,2,3,4-tetrahydroisoquinolin-6-ol showing 79% efficacy at 100 µM as an inverse agonist, being more active than DES (64% at 100 µM). Inhibition of steroidogenic enzymes like 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) is an emerging approach for the treatment of HDBC, compared to other current clinical strategies. THIQs evaluated against 17β-HSD1 showed good activity in both whole cell and cell lysate assays, with the best inhibitor, 2-(4-chlorophenyl)-4-isopropyl-1,2,3,4-tetrahydroisoquinolin-6-ol, possessing an IC50 value of 336 nM. The value of THIQ as a drug-like steroidomimetic scaffold is thus established and this work reveals straightforward strategies to optimise potency and selectivity for a range of potential targets by structural and stereochemical iteration.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Anticoagulants are the basis for treatment and prevention of thrombotic diseases. The currently available medicines are associated with a wide range of adverse reactions that mandates developing new anticoagulants. Several lines of evidence support the superiority of factor Xa (FXa) as a promising target to develop novel anticoagulants. This work focuses on the design of direct and indirect FXa inhibitors using an interdisciplinary approach. As indirect FXa inhibitors, a focused library of tetrasulfated N–arylacyl tetrahydroisoquinoline (THIQ) nonsaccharide allosteric antithrombin activators was designed, synthesized, and biochemically evaluated to establish their structure–activity relationship (SAR). An N–arylacyl THIQ analog having carboxylate at position–3, two sulfate groups at positions–5 and –8 of THIQ moiety, butanoyl linker, and two sulfate groups at positions–2 and –5 of the phenolic monocyclic moiety was identified as the most promising nonsaccharide antithrombin activator with KD of 1322 ± 237 μM and acceleration potential of 80–fold. Its biochemical profile indicates a strong possibility that it activates antithrombin by the pre–equilibrium pathway rather than the induced–fit mechanism utilized by heparin analogs. A similar interdisciplinary approach was exploited to design direct FXa inhibitors that possess high selectivity and are potentially orally bioavailable. Structurally, the designed direct FXa inhibitors are neutral THIQ dicarboxamides. THIQ dicarboxamide is a privileged structure with a semi–rigid character, a structural feature that potentially offers high selectivity for targeting FXa over other coagulation and digestive proteases. It can also be thought of as an amino acid–like structure, which affords accessibility to a large number of compounds using well established peptide chemistry. Mechanistically, the designed inhibitors were expected to bind to FXa in the active site and function as orthosteric inhibitors. These direct FXa active site inhibitors are also likely to inhibit clot–bound enzyme. Nearly 60 THIQ dicarboxamides were synthesized and biochemically evaluated. Through detailed SAR analysis, the most potent analog was designed and found to exhibit an IC50 of 270 nM (Ki = 135 nM), an improvement of more than 207–fold over the first inhibitor synthesized in the study. The most potent inhibitor displayed at least 1887–fold selectivity for FXa over other coagulation enzymes and a selectivity index of at least 279–fold over the digestive serine proteases. This analog doubled plasma clotting times at 17–20 μM, which are comparable to those of agents being currently studied in clinical trials. Overall, allosteric and orthosteric approaches led to the design of indirect and direct small molecule inhibitors of FXa based on the THIQ scaffold. This work introduces two promising molecules, a tetrasulfated N–arylacyl THIQ analog as a heparin mimetic and a neutral THIQ dicarboxamide as a potent, selective, and potentially bioavailable peptidomimetic, for further advanced medicinal chemistry studies.