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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Antibiotic-conjugated polyacrylate nanoparticles: New opportunities for development of anti-MRSA agents

Wang, Yang 01 June 2006 (has links)
N-Thiolated B-lactams represent a novel family of antibacterial agents, whose in vitro activity is confined largely to Staphylococcus species, including multidrug-resistant forms of S. aureus. N-Thiolated B-lactams have recently been shown to possess intriguing biological activities which are addressed in Chapter II. Current development of nanoparticles as a new drug delivery vehicle is described in Chapter III. Chapter IV and V described the current research in our laboratories focusing on the synthesis and characterization of emulsified polyacrylate/polyacrylamide nanoparticle antibacterials for drug delivery of water-insoluble antibiotics. These nanoparticles can be prepared in aqueous media directly from acrylate/acrylamide monomers through free radical microemulsion polymerization. These emulsions contain antibiotic-conjugated polyacrylate nanospheres measuring 30-60 nm in diameter and have enhanced antibacterial activity against drug resistant S. aureus (MRSA) through what we believe is a novel mechanism.
2

ISOXAZOLIDINONE-CONTAINING COMPOUNDS AS NON-β-LACTAM ANTIBIOTICS: SYNTHESIS AND PRELIMINARY STUDY OF THEIR MODE OF ACTION

Cao, Xuefei 11 October 2001 (has links)
No description available.
3

Antibiotic Resistance in Wastewater : Methicillin-resistant Staphylococcus aureus (MRSA)and antibiotic resistance genes / Resistenta gula stafylokocker (MRSA) och antibiotikaresistensgener förekommer i svenskt kommunalt avloppsvatten

Börjesson, Stefan January 2009 (has links)
A large part of the antibiotics consumed ends up in wastewater, and in the wastewater the antibiotics may exert selective pressure for or maintain resistance among microorganisms. Antibiotic resistant bacteria and genes encoding antibiotic resistance are commonly detected in wastewater, often at higher rates and concentrations compared to surface water. Wastewater can also provide favourable conditions for the growth of a diverse bacterial community, which constitutes a basis for the selection and spread of antibiotic resistance. Therefore, wastewater treatment plants have been suggested to play a role in the dissemination and development of antibiotic resistant bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) is a large problem worldwide as a nosocomial pathogen, but knowledge is limited about occurrence in non-clinical environments, such as wastewater, and what role wastewater plays in dissemination and development of MRSA.   In this thesis we investigated the occurrence of MRSA in a full-scale wastewater treatment plant (WWTP). We also investigated the concentration of genes encoding resistance to aminoglycosides (aac(6’)-Ie+aph(2’’)), β-lactam antibiotics (mecA) and tetracyclines (tetA and tetB) in three wastewater-associated environments: (1) soil from an overland flow area treating landfill leachates, (2) biofilm from a municipal wastewater treatment plant, and (3) sludge from a hospital wastewater pipeline. In addition, concentrations of mecA, tetA and tetB were investigated over the treatment process in the WWTP. These investigations were performed to determine how the prevalence and concentration of MRSA and the antibiotic resistence genes are affected in wastewater and wastewater treatment processes over time. The occurrence of MRSA was investigated by cultivation and a commercially available real-time PCR assay. In order to determine concentrations of the genes aac(6’)-Ie+aph(2’’), mecA, tetA and tetB in wastewater we developed a LUXTM real-time PCR assay for each gene.   Using cultivation and real-time PCR we could for the first time describe the occurrence of MRSA in wastewater and show that it had a stable occurrence over time in a WWTP. MRSA could mainly be detected in the early treatment steps in the WWTP, and the wastewater treatment process reduced the number and diversity of cultivated MRSA. However, our results also indicate that the treatment process selects for strains with more extensive resistance and possibly higher virulence. The isolated wastewater MRSA strains were shown to have a close genetic relationship to clinical isolates, and no specific wastewater lineages could be detected, indicating that they are a reflection of carriage in the community. Taken together, these data indicate that wastewater may be a potential reservoir for MRSA and that MRSA are more prevalent in wastewater than was previously thought.   The real-time PCR assays, for aac(6’)-Ie+aph(2’’), mecA, tetA, and tetB that we developed, were shown to be sensitive, fast, and reproducible methods for detection and quantification of these genes in wastewater environments. The highest concentrations of all genes were observed in the hospital pipeline, and the lowest in the overland flow system, with tetA and aac(6´)-Ie+aph(2´´) detected in all three environments. In the full-scale WWTP, we continuously detected mecA, tetA and tetB over the treatment process and over time. In addition, it was shown that the treatment process reduces concentrations of all three genes. The data presented in this thesis also indicate that the reduction for all three genes may be connected to the removal of biomass, and in the reduction of tetA and tetB, sedimentation and precipitation appear to play an important role.
4

Modelagem farmacocinética-farmacodinâmica da piperacilina em ratos imunodeprimidos infectados com Escherichia coli

Araújo, Bibiana Verlindo de January 2002 (has links)
Objetivos: Avaliar a adequabilidade do modelo farmacocinético-farmacodinâmico (PK-PD) (NOLTING et al., 1996b) para modelar o efeito bactericida da piperacilina (PIP) em ratos Wistar infectados experimentalmente com Escherichia coli ATCC 25922. Metodologia: Experimentos de Farmacocinética: Determinou-se as concentrações plasmáticas totais e livres teciduais de PIP, através de microdiálise (MD), após administração de 240 mg/kg i.v. bolus a ratos Wistar granulocitopênicos (ciclofosfamida) infectados no músculo esquelético (105 UFC/mL) com E. coli. As amostras de plasma e de MD foram analisadas por CLAE. As sondas de MD foram calibradas por retrodiálise. Experimentos de Farmacodinâmica: Os animais imunodeprimidos e infectados foram tratados com PIP nas doses de 120 ou 240 mg/kg, em intervalos de 4/4, 6/6 e 8/8 horas por 24 h. Em tempos pré-determinados, os animais foram sacrificados (n = 3/tempo), o músculo infectado foi retirado, homogeneizado e o número de UFC/mL foi determinado em placas de ágar-sangue, após diluições sucessivas. Um grupo não tratado foi utilizado como controle. Modelagem PK-PD: A partir dos dados farmacocinéticos e farmacodinâmicos obtidos, avaliou-se efeito de morte bacteriana em função do tempo com o auxílio do programa de regressão não-linear SCIENTIST® v.2.0. Resultados e Discussão: Os parâmetros farmacocinéticos após a administração de PIP (240 mg/kg) foram t½ de 40 ± 8 min; CL de 0,46 ± 0,021 (L/h/kg) e um Vdss de 0,30 ± 0,06 L/kg. O perfil de PIP livre tecidual foi previsto a partir dos parâmetros plasmáticos utilizando ajuste simultâneo dos dados de plasma e tecido e um fator de proporcionalidade de 0,342 ± 0,101. Os parâmetros do modelo PK-PD obtidos foram: EC50 de 1,31 ± 0,27 μg/mL e kmax 1,39 ± 0,20 h-1. Os valores dos parâmetros da modelagem PK-PD obtidos in vivo diferiram dos descritos na literatura para o mesmo antibiótico e bactéria quando simulados in vitro. Conclusões: O modelo Emax-modificado descreveu os perfis de crescimento e morte bacteriana em função do tempo obtidos nas diferentes posologias testadas sendo adequado para modelagem PK-PD da piperacilina nas condições experimentais investigadas. / Purpose: The objective of this study was to model the killing effect of a β-lactam antibiotic, piperacillin (PIP), in neutropenic and E. coli ATCC 25922 infected rats after different dosing regimens using a modified Emax PK-PD model. Methodology: Pharmacokinetic studies: Total plasma and free tissue concentrations of PIP, determined by microdialysis, were investigated after i.v. bolus of 240 mg/kg of the drug to immunecompromised (cyclophosphamide) and E. coli infected (107 CFU) Wistar rats. Microdialysis probes recoveries were determined by retrodialysis. Plasma and tissue samples were analyzed by HPLC. Pharmacodynamic studies: The infected rats were treated with iv bolus PIP 120 mg/kg or 240 mg/kg q8h, q6h, q4h. Three animals were sacrificed at predetermined times up to 24 hours. The infected muscle was removed, homogenized and the number of CFU/mL was determined by plate counting after 24 hours of incubation at 37ºC. A control group without treatment was used. PK-PD modeling: PIP killing effect as a function of time was fitted using the Emax-modified model with the aid of a non-linear regression computer program SCIENTIST® v.2.0. Results and Discussion: The pharmacokinetic parameters determined for PIP 240 mg/kg iv bolus were: t½ of 40 ± 8 min; CL of 0.46 ± 0.021 (L/h/kg) and Vdss of 0.30 ± 0.06 L/kg. Piperacillin free tissue levels were predicted using plasma data ina a simultaneous fitting with a proportionality factor of 0.342 ± 0.101. The parameters derived from PK-PD modeling were: bacterial killing rate (kmax) of 1.39 ± 0.20 h-1 concentration to produce 50% of de maximum effect (EC50) of 1.31 ± 0.27 μg/mL. The PK-PD parameters determined in vivo were different from those reported for the same bacteria and drug in vitro. Conclusions: The Emax model adequately described PIP antibacterial effect in animals for the different dosing regimens investigated.
5

Modelagem farmacocinética-farmacodinâmica da piperacilina em ratos imunodeprimidos infectados com Escherichia coli

Araújo, Bibiana Verlindo de January 2002 (has links)
Objetivos: Avaliar a adequabilidade do modelo farmacocinético-farmacodinâmico (PK-PD) (NOLTING et al., 1996b) para modelar o efeito bactericida da piperacilina (PIP) em ratos Wistar infectados experimentalmente com Escherichia coli ATCC 25922. Metodologia: Experimentos de Farmacocinética: Determinou-se as concentrações plasmáticas totais e livres teciduais de PIP, através de microdiálise (MD), após administração de 240 mg/kg i.v. bolus a ratos Wistar granulocitopênicos (ciclofosfamida) infectados no músculo esquelético (105 UFC/mL) com E. coli. As amostras de plasma e de MD foram analisadas por CLAE. As sondas de MD foram calibradas por retrodiálise. Experimentos de Farmacodinâmica: Os animais imunodeprimidos e infectados foram tratados com PIP nas doses de 120 ou 240 mg/kg, em intervalos de 4/4, 6/6 e 8/8 horas por 24 h. Em tempos pré-determinados, os animais foram sacrificados (n = 3/tempo), o músculo infectado foi retirado, homogeneizado e o número de UFC/mL foi determinado em placas de ágar-sangue, após diluições sucessivas. Um grupo não tratado foi utilizado como controle. Modelagem PK-PD: A partir dos dados farmacocinéticos e farmacodinâmicos obtidos, avaliou-se efeito de morte bacteriana em função do tempo com o auxílio do programa de regressão não-linear SCIENTIST® v.2.0. Resultados e Discussão: Os parâmetros farmacocinéticos após a administração de PIP (240 mg/kg) foram t½ de 40 ± 8 min; CL de 0,46 ± 0,021 (L/h/kg) e um Vdss de 0,30 ± 0,06 L/kg. O perfil de PIP livre tecidual foi previsto a partir dos parâmetros plasmáticos utilizando ajuste simultâneo dos dados de plasma e tecido e um fator de proporcionalidade de 0,342 ± 0,101. Os parâmetros do modelo PK-PD obtidos foram: EC50 de 1,31 ± 0,27 μg/mL e kmax 1,39 ± 0,20 h-1. Os valores dos parâmetros da modelagem PK-PD obtidos in vivo diferiram dos descritos na literatura para o mesmo antibiótico e bactéria quando simulados in vitro. Conclusões: O modelo Emax-modificado descreveu os perfis de crescimento e morte bacteriana em função do tempo obtidos nas diferentes posologias testadas sendo adequado para modelagem PK-PD da piperacilina nas condições experimentais investigadas. / Purpose: The objective of this study was to model the killing effect of a β-lactam antibiotic, piperacillin (PIP), in neutropenic and E. coli ATCC 25922 infected rats after different dosing regimens using a modified Emax PK-PD model. Methodology: Pharmacokinetic studies: Total plasma and free tissue concentrations of PIP, determined by microdialysis, were investigated after i.v. bolus of 240 mg/kg of the drug to immunecompromised (cyclophosphamide) and E. coli infected (107 CFU) Wistar rats. Microdialysis probes recoveries were determined by retrodialysis. Plasma and tissue samples were analyzed by HPLC. Pharmacodynamic studies: The infected rats were treated with iv bolus PIP 120 mg/kg or 240 mg/kg q8h, q6h, q4h. Three animals were sacrificed at predetermined times up to 24 hours. The infected muscle was removed, homogenized and the number of CFU/mL was determined by plate counting after 24 hours of incubation at 37ºC. A control group without treatment was used. PK-PD modeling: PIP killing effect as a function of time was fitted using the Emax-modified model with the aid of a non-linear regression computer program SCIENTIST® v.2.0. Results and Discussion: The pharmacokinetic parameters determined for PIP 240 mg/kg iv bolus were: t½ of 40 ± 8 min; CL of 0.46 ± 0.021 (L/h/kg) and Vdss of 0.30 ± 0.06 L/kg. Piperacillin free tissue levels were predicted using plasma data ina a simultaneous fitting with a proportionality factor of 0.342 ± 0.101. The parameters derived from PK-PD modeling were: bacterial killing rate (kmax) of 1.39 ± 0.20 h-1 concentration to produce 50% of de maximum effect (EC50) of 1.31 ± 0.27 μg/mL. The PK-PD parameters determined in vivo were different from those reported for the same bacteria and drug in vitro. Conclusions: The Emax model adequately described PIP antibacterial effect in animals for the different dosing regimens investigated.
6

Modelagem farmacocinética-farmacodinâmica da piperacilina em ratos imunodeprimidos infectados com Escherichia coli

Araújo, Bibiana Verlindo de January 2002 (has links)
Objetivos: Avaliar a adequabilidade do modelo farmacocinético-farmacodinâmico (PK-PD) (NOLTING et al., 1996b) para modelar o efeito bactericida da piperacilina (PIP) em ratos Wistar infectados experimentalmente com Escherichia coli ATCC 25922. Metodologia: Experimentos de Farmacocinética: Determinou-se as concentrações plasmáticas totais e livres teciduais de PIP, através de microdiálise (MD), após administração de 240 mg/kg i.v. bolus a ratos Wistar granulocitopênicos (ciclofosfamida) infectados no músculo esquelético (105 UFC/mL) com E. coli. As amostras de plasma e de MD foram analisadas por CLAE. As sondas de MD foram calibradas por retrodiálise. Experimentos de Farmacodinâmica: Os animais imunodeprimidos e infectados foram tratados com PIP nas doses de 120 ou 240 mg/kg, em intervalos de 4/4, 6/6 e 8/8 horas por 24 h. Em tempos pré-determinados, os animais foram sacrificados (n = 3/tempo), o músculo infectado foi retirado, homogeneizado e o número de UFC/mL foi determinado em placas de ágar-sangue, após diluições sucessivas. Um grupo não tratado foi utilizado como controle. Modelagem PK-PD: A partir dos dados farmacocinéticos e farmacodinâmicos obtidos, avaliou-se efeito de morte bacteriana em função do tempo com o auxílio do programa de regressão não-linear SCIENTIST® v.2.0. Resultados e Discussão: Os parâmetros farmacocinéticos após a administração de PIP (240 mg/kg) foram t½ de 40 ± 8 min; CL de 0,46 ± 0,021 (L/h/kg) e um Vdss de 0,30 ± 0,06 L/kg. O perfil de PIP livre tecidual foi previsto a partir dos parâmetros plasmáticos utilizando ajuste simultâneo dos dados de plasma e tecido e um fator de proporcionalidade de 0,342 ± 0,101. Os parâmetros do modelo PK-PD obtidos foram: EC50 de 1,31 ± 0,27 μg/mL e kmax 1,39 ± 0,20 h-1. Os valores dos parâmetros da modelagem PK-PD obtidos in vivo diferiram dos descritos na literatura para o mesmo antibiótico e bactéria quando simulados in vitro. Conclusões: O modelo Emax-modificado descreveu os perfis de crescimento e morte bacteriana em função do tempo obtidos nas diferentes posologias testadas sendo adequado para modelagem PK-PD da piperacilina nas condições experimentais investigadas. / Purpose: The objective of this study was to model the killing effect of a β-lactam antibiotic, piperacillin (PIP), in neutropenic and E. coli ATCC 25922 infected rats after different dosing regimens using a modified Emax PK-PD model. Methodology: Pharmacokinetic studies: Total plasma and free tissue concentrations of PIP, determined by microdialysis, were investigated after i.v. bolus of 240 mg/kg of the drug to immunecompromised (cyclophosphamide) and E. coli infected (107 CFU) Wistar rats. Microdialysis probes recoveries were determined by retrodialysis. Plasma and tissue samples were analyzed by HPLC. Pharmacodynamic studies: The infected rats were treated with iv bolus PIP 120 mg/kg or 240 mg/kg q8h, q6h, q4h. Three animals were sacrificed at predetermined times up to 24 hours. The infected muscle was removed, homogenized and the number of CFU/mL was determined by plate counting after 24 hours of incubation at 37ºC. A control group without treatment was used. PK-PD modeling: PIP killing effect as a function of time was fitted using the Emax-modified model with the aid of a non-linear regression computer program SCIENTIST® v.2.0. Results and Discussion: The pharmacokinetic parameters determined for PIP 240 mg/kg iv bolus were: t½ of 40 ± 8 min; CL of 0.46 ± 0.021 (L/h/kg) and Vdss of 0.30 ± 0.06 L/kg. Piperacillin free tissue levels were predicted using plasma data ina a simultaneous fitting with a proportionality factor of 0.342 ± 0.101. The parameters derived from PK-PD modeling were: bacterial killing rate (kmax) of 1.39 ± 0.20 h-1 concentration to produce 50% of de maximum effect (EC50) of 1.31 ± 0.27 μg/mL. The PK-PD parameters determined in vivo were different from those reported for the same bacteria and drug in vitro. Conclusions: The Emax model adequately described PIP antibacterial effect in animals for the different dosing regimens investigated.
7

Μελέτες με σκοπό την ολική σύνθεση της Ecteinascidin 743 : νέες συνθετικές μεθοδολογίες στη φαρμακευτική χημεία

Ψαρρά, Βασιλική 19 April 2010 (has links)
Η Ecteinascidin 743 είναι ένα σπουδαίο αντικαρκινικό φάρμακο, που καταστρέφει μέσω αλκυλίωσης τα καρκινικά κυττάρα και είναι εμπορικά διαθέσιμο με το όνομα Yondelis. Χρησιμοποιείται στην Ευρώπη, τη Ρωσία και τη Νότια Κορέα για τη θεραπεία του σαρκώματος του μαλακού ιστού, δηλαδή καρκίνου των ιστών που υποστηρίζουν το σώμα, όπως οι μύες, τα αιμοφόρα αγγεία και άλλα είδη ιστών που υποστηρίζουν και προστατεύουν τα όργανα του σώματος. Η Ecteinascidin 743 βρίσκεται υπό κλινικές δοκιμές για τη θεραπεία και άλλων μορφών καρκίνου, όπως του καρκίνου του μαστού, του προστάτη, των ωοθηκών, των νεφρών, των πνευμόνων και του μελανώματος. Απομονώθηκε από το μικρό θαλάσσιο οργανισμό, Ecteinascidia turbinate, που ζει στις θάλασσες της Καραϊβικής και ανακαλύφθηκε ότι έχει αντικαρκινική δράση το 1969. Αυτό το φυσικό προϊόν αποτέλεσε πηγή έμπνευσης για την παρούσα ερευνητική εργασία, όπου στην ρετροσυνθετική του πορεία (Εικόνα 3) περιλαμβάνεται η σύνθεση ενός μορίου πιπεραζίνης, καθώς και ενός β-λακταμικού δακτυλίου. Οι β-λακτάμες χρησιμοποιούνται σήμερα ως βακτηριοκτόνα, αντιβιοτικά, αναστολείς των πρωτεασών σερίνης και αναστολείς της ακυλομεταφεράσης της χοληστερολης (acyl-CoA: cholesterol acyltransferase, ACAT), η οποία είναι υπεύθυνη κυρίως για την αθηροσκληρωτική στεφανιαία καρδιακή νόσο. Η ασθένεια αυτή αποτελεί ήδη την πιο κοινή μορφή ασθένειας που προσβάλλει την καρδιά και μία σημαντική αιτία πρόωρου θανάτου στην Ευρώπη, σε κράτη της Βαλτικής, τη Ρωσία, τη Βόρεια και Νότια Αμερική, την Αυστραλία και τη Νέα Ζηλανδία. Η αθηροσκλήρωση σχετίζεται με την στεφανιαία καρδιακή νόσο, η οποία αποδίδεται στην ανικανότητα της στεφανιαίας κυκλοφορίας να τροφοδοτεί με επαρκές αίμα το μυ της καρδιάς και τους περιβάλλοντες ιστούς. Οι παράγοντες που οδηγούν στην αθηροσκλήρωση είναι τα υψηλά επίπεδα χοληστερόλης, η υπέρταση, ο διαβήτης, το κάπνισμα, οι κακές διατροφικές συνήθειες, η παχυσαρκία και η έλλειψη σωματικής άσκησης. Οι παραπάνω δράσεις των β-λακταμών έχουν καταστήσει πολύ ενδιαφέρουσα τη στερεοεκλεκτική και εναντιοεκλεκτική σύνθεση αυτών. Ένας β-λακταμικός δακτύλιος είναι μία λακτάμη με δομή ετεροατομικού τετραμελούς δακτυλίου, που αποτελείται από τρία άτομα άνθρακα και ένα άτομο αζώτου. Ο β-λακταμικός δακτύλιος είναι μέρος της δομής μερικών κατηγοριών β- λακταμικών αντιβιοτικών, όπως οι πενικιλίνες, οι κεφαλοσπορίνες, οι κεφαμυκίνες, οι καρβαπενέμες, οι μονοβακτάμες, και οι τρινέμες. Οι ενώσεις των β-λακταμών παρασκευάστηκαν σύμφωνα με την Mannich αντίδραση μέσω σουλφινιμινών. Οι πιπεραζίνες χρησιμοποιούνται σήμερα ως μυκητοκτόνα, αγχολυτικά, αντιικά, και ανταγωνιστές του υποδοχέα της σεροτονίνης (5-HT). Η τελευταία θεραπευτική ικανότητα των πιπεραζινών είναι πλέον ένα θέμα εκτενούς επιστημονικής έρευνας και περιλαμβάνει υποδοχείς-στόχους που ανήκουν στην κατηγορία των υποδοχέων συζευγμένων με G-πρωτεΐνη (G-ptotein-coupled receptors, GPCRs). Η εκλεκτικότητα των πιπεραζινών για τις GPCRs εμφανίζεται εξαιτίας της βασικότητας. Αυξάνοντας το μέγεθος του όρθο υποκαταστάτη σε Ν-άρυλο πιπεραζίνες, αυξάνεται η ικανότητα πρόσδεσής τους και η λειτουργική τους δραστικότητα. Οι πιπεραζίνες είναι οργανικές ενώσεις, που αποτελούνται από έναν εξαμελή δακτύλιο, ο οποίος περιέχει δύο άτομα αζώτου, που βρίσκονται στις θέσεις 1 και 4 του δακτυλίου. Οι ενώσεις των πιπεραζινών παρασκευάστηκαν σύμφωνα με την Diels-Alder αντίδραση μέσω σουλφινιμινών. Οι σουλφινιμίνες αποτέλεσαν το μόριο-κλειδί για την σύνθεση όλων των τελικών επιθυμητών προϊόντων και είναι γνωστές ως πολύ καλοί πρόδρομοι αμινών, όταν αντιδράσουν με οργανομεταλλικές ενώσεις [RLi, RMgX (αντιδραστήρια οργανολιθίου, αντιδραστήρια Grignard)]. Οι οπτικώς καθαρές σουλφινιμίνες είναι σημαντικές δομικές μονάδες (building blocks) στην ασύμμετρη σύνθεση άμινο παραγώγων, και παρασκευάζονται σε πολύ καλές αποδόσεις μέσω ενός σταδίου από αρωματικές, ετεροαρωματικές και αλιφατικές αλδεΰδες. Στην παρούσα ερευνητική μελέτη συντέθηκαν νέες β-λακταμικές ενώσεις και υποκατεστημένες ενώσεις πιπεραζίνης, συμπληρώνοντας έτσι και ενισχύοντας τα ήδη υπάρχοντα δεδομένα για τις συγκεκριμένες κατηγορίες ενώσεων αφενός και, αφετέρου, παρέχοντας νέα δεδομένα για την ολική σύνθεση του φυσικού προϊόντος, Ecteinascidin 743 (σύνθεση των εξαμελών αζόξυ προϊόντων 18, 19 και 20). Η ρετροσυνθετική ανάλυση της Ecteinascidin 743, που περιγράφηκε αρχικά, δύναται να εφαρμοστεί, σύμφωνα με τα αποτελέσματα της παρούσας ερευνητικής εργασίας. / Ecteinascidin 743 is an important antitumor drug that can service a novel way of killing cancer cells, and it is sold under the brand name Yondelis. It has been approved for use in Europe, Russia and South Korea for the treatment of advanced soft tissue sarcoma, cancers of the supporting tissues of the body, such as muscles, fat, blood vessels or in any other tissues that support, surround and protect the organs of the body. Ecteinascidin 743 is undergoing clinical trials for the treatment of breast, prostate, ovarian, renal, lung, and melanoma cancers. It is isolated from the Caribbean tunicate Ecteinascidia turbinate, and was found to have anticancer activity in 1969. We were inpired by this natural product and as we can observe from its retrosynthetic analysis (Scheme 3), the synthesis of a piperazine molecule and a β-lactam ring are involved. The extreme importance of β-lactams serving not only as bactericidal and as key structural units of several important antibiotics, but also as mechanism-based inhibitors of serine proteases and as inhibitors of acyl-CoA cholesterol acyltransferase (ACAT), which is mainly responsible for atherosclerotic coronary heart disease. Coronary heart disease is already the most common form of disease affecting the heart and is an important cause of premature death in Europe, the Baltic states, Russia, North and South America, Australia and New Zealand. Atherosclerosis is most commonly equated with atherosclerotic coronary artery disease, which is rendered in the failure of the artery circulation to supply with sufficient blood the heart muscle and the surrounding tissues. Risk factors for the coronary heart disease include high levels of cholesterol, hypertension, diabetes, smoking, bad diet habbits, obesity, and lack of excercise. The above activities of β-lactams have propelled strong resurgent interest toward their stereoselective and enantioselective synthesis. A β-lactam ring is a lactam with a heteroatomic four-membered ring structure, consisting of three carbon atoms and one nitrogen atom. Penicillins, cephalosporins, cephamycins, carbapenems, monobactams, and trinems are classified as b-lactam antibiotics. β-Lactams were prepared by the Mannich reaction using sulfinimines. Piperazines are used now-a-days as antifungals,antidepressants, antiviral, and serotonin receptor antagonists (5-HT). The latter therapeutic area of piperazines has been the subject of intense research and includes targets belonging to the G-Protein- Coupled Receptor (GPCR) superfamily. The selectivity of piperazines towards GPCRs has deen attributed to their basicity. Increasing the size of the ortho substituent in N-aryl piperazines resulted in an increase in binding affinity and functional potency. Piperazines are organic compounds that consists of a six-membered ring containing two opposing nitrogen atoms, at the 1 and 4 positions of the ring. Piperazines were prepared by the Diels-Alder reaction using sulfinimines. Sulfinimines are the key-compounds for the synthesis of the final desirable products described herein and excellent precursors of amines, when they react with organometallic compounds [RLi, RMgX (organolithium reagents, Grignard reagents)]. Enantiomerically pure sulfinimines representing, important building blocks in the asymmetric synthesis of amine derivatives, are prepared in high yields in one step from aromatic, heteroaromatic, and aliphatic aldehydes. In this project, novel β-lactam compounds and substituted piperazine compounds were synthesized, in order to complete and highlight the already existing data for these specific compounds classes and provide new data about the total synthesis of the natural product, Ecteinascidin 743 (synthesis of six-membered azoxy products 18, 19 and 20). The retrosynthetic analysis of Ecteinascidin 743 could be viable given the result described in Scheme 44.

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