National Repository of Grey Literature 10 records found  Search took 0.01 seconds. 
Design and Synthesis of Prodrugs of 6-Diazo-5-oxo-L-norleucine; Potential Treatment for Glioblastoma
Novotná, Kateřina ; Majer, Pavel (advisor) ; Rýček, Lukáš (referee)
6-Diazo-5-oxo-L-norleucine (DON, 1) is a non-standard amino acid with proven antitumor activity found in soil bacteria of the genus Streptomyces. However, due to the considerable systemic toxicity manifested mainly in the gastrointestinal tract, DON alone is not a suitable clinical candidate for the treatment of cancer. One of the ways to solve the problem of its toxicity is the reversible structural modification of this molecule by protecting both its amino group and carboxyl functional group, by preparing the so-called prodrug of DON. The prepared prodrug may suitably alter the distribution of DON in the body and at the same time increase its permeability to brain tissue. Due to this structural modification, its side effects can be eliminated and a substance for the treatment of brain tumors, such as glioblastoma multiforme (GBM), can potentially be formed. In my dissertation, five strategies for the specific delivery of DON to the brain using different types of its prodrugs are discussed. The new prodrugs are designed to be either capable of spontaneous penetration across the blood-brain barrier or of being a substrate for one of its influx transporters. At the same time, these prodrugs should be stable in other metabolically active organs and blood plasma in order to sufficiently reduce the...
Design and synthesis of novel type of prodrugs of acyclic nucleoside phosphonates based on ProTides
Markušová, Katarína ; Janeba, Zlatko (advisor) ; Kundrát, Ondřej (referee)
This diploma thesis focuses on the synthesis of novel prodrugs of tenofovir, one of the main components of medications against human immunodeficiency virus (HIV) infection. The design of the compounds is based on the concept of ProTides and takes inspiration from the previous work of Filip Kalčic. In this work, the aromatic ester on the phosphonate moiety, typical for the ProTides, is replaced by an aliphatic ester. This aliphatic moiety is represented by a derivative of the amino acid L-serine. All of the target compounds were synthesized in a one-pot manner from three key components (L-serine, L-alanine, and tenofovir), except for one, the synthesis of which remains unsuccessful. The prepared compounds exhibit single-digit micromolar to low nanomolar potency against HIV-1. The most active compound (as a mixture of epimers) exhibited similar anti-HIV-1 activity to the reference ProTide prodrug, tenofovir alafenamide. Most importantly, none of the synthesized ProTides showed cytotoxicity. This was one of the key properties of the compounds from Kalčic's project that we wanted to improve. The results of this thesis represent a stepping stone to a new category of ProTide prodrugs of phosphonates. Key words: prodrugs, acyclic nucleoside phosphonates, ProTides, tenofovir, serine, TAF
Synthesis of novel types of acyclic nucleoside phosphonates and preparation of prodrugs and drug delivery systems
Kalčic, Filip ; Janeba, Zlatko (advisor) ; Míšek, Jiří (referee) ; Krečmerová, Marcela (referee)
First part of this thesis was focused on the previously overlooked field of C1'-branched acyclic nucleoside phosphonates (ANPs). Five diverse synthetic approaches were developed/optimized affording key 6-chloropurine intermediates bearing N9 -phosphonomethoxyethyl (PME) branched at C1' position in 2-4 steps. It was demonstrated that these intermediates can be further vastly diversified into ANPs bearing both natural and unnatural nucleobases. Single enantiomers as well as racemates of final C1'-branched ANPs (overall 48 final compounds) were prepared and selected compounds were evaluated with respect to their biological properties. The aforementioned ANPs showed no antiviral potency against studied viruses and only weak to moderate cytostatic activity. Adenine C1'-branched ANPs proved to be the most potent currently known inhibitors of Trypanosoma brucei adenine phosphoribosyl transferase (TbrAPRT), an enzyme involved in purine salvage pathway (PSP) of T. brucei. Further biological evaluation of prepared compounds is in progress. Second part of this thesis was focused on development of novel prodrug moieties with higher selectivity index (i.e. toxicity/potency ratio - SI) based on so-called ProTide prodrugs where phenol (present in ProTides) was replaced by tyrosine derivatives. Tenofovir was...
Synthesis of nucleoside analogs based on derivatives of 2-deoxy-2-fluoro- and 3-deoxy-3-fluoro-D-ribose and pyrazines
Smolka, Ondřej ; Jindřich, Jindřich (advisor) ; Smrček, Stanislav (referee)
This thesis deals with the synthesis of prodrugs based on analogs of nucleoside phosphonates derived from 6-fluoro-3-hydroxypyrazine-2-carboxamide (T-705) and 3- hydroxypyrazine-2-carboxamide (T-1105). T-705 and T-1105 act as inhibitors of an influenza RNA polymerase. Both compounds mimic naturally occurring nucleobases, so their fluorinated nucleoside phosphonates could also be biologically active. Derivatives of 2-deoxy-2-fluoro-D-ribose (2-FdR) were prepared in this work. Because of complications during the syntthesis of 3-deoxy-3-fluoro-D-ribose (3-FdR) derivatives, 5- deoxy-5-fluoro-D-xylose (5-FdX) derivatives were prepared instead. Deoxyfluorination was done after incorporation of suitable protecting groups followed by selective deprotection and phosphonate binding. Furthermore nucleosides were synthetised using silyl-Hilbert-Johnson method and their bis-POM derivattives were also prepared. Key words: favipiravir (T-705), T-1105, prodrugs, phosphonates, fluorinated nucleosides
Design and Synthesis of Prodrugs of 6-Diazo-5-oxo-L-norleucine; Potential Treatment for Glioblastoma
Novotná, Kateřina ; Majer, Pavel (advisor) ; Rýček, Lukáš (referee)
6-Diazo-5-oxo-L-norleucine (DON, 1) is a non-standard amino acid with proven antitumor activity found in soil bacteria of the genus Streptomyces. However, due to the considerable systemic toxicity manifested mainly in the gastrointestinal tract, DON alone is not a suitable clinical candidate for the treatment of cancer. One of the ways to solve the problem of its toxicity is the reversible structural modification of this molecule by protecting both its amino group and carboxyl functional group, by preparing the so-called prodrug of DON. The prepared prodrug may suitably alter the distribution of DON in the body and at the same time increase its permeability to brain tissue. Due to this structural modification, its side effects can be eliminated and a substance for the treatment of brain tumors, such as glioblastoma multiforme (GBM), can potentially be formed. In my dissertation, five strategies for the specific delivery of DON to the brain using different types of its prodrugs are discussed. The new prodrugs are designed to be either capable of spontaneous penetration across the blood-brain barrier or of being a substrate for one of its influx transporters. At the same time, these prodrugs should be stable in other metabolically active organs and blood plasma in order to sufficiently reduce the...
Synthesis of prodrugs of glutamine antimetabolite 6-diazo-5-oxo-L-norleucine
Novotná, Kateřina ; Majer, Pavel (advisor) ; Machara, Aleš (referee)
The 6-diazo-5-oxo-L-norleucine (DON) is a glutamine antimetabolite, which has shown promissing antitumor activity in preclinical and several clinical studies. However, its high toxicity leading to gastrointestinal side effects prevented its further development. The aim of this Bachelor thesis was to prepare DON prodrugs with similar anticancer activity but less side effects. Biochemical and biological tests of synthesized prodrugs were performed at Johns Hopkins University in Baltimore (USA). Key words: 6-diazo-5-oxo-L-norleucine (DON), prodrugs, antimetabolite, ProTide
Synthesis of novel prodrugs for antiviral therapy
Štefek, Milan ; Nencka, Radim (advisor) ; Janeba, Zlatko (referee)
This bachelor thesis is dedicated to preparation of prodrugs derived from 2'-C- methyladenosine, which is a potent inhibitor of the RNA dependent RNA polymerase of flaviviruses. Prodrugs modifying 3' and 5' hydroxy groups able to deliver the drug to brain and were prepared. As targeting moieties tropine and the redox system trigonelline/1,4- dihydrotrigonelline were used. In the case of tropine a suitable method for the preparation of prodrugs was developed. Reliable procedure for performing the last step of synthesis of compounds utilizing the trigonelline redox system is yet to be discovered.
Synthesis of novel cytostatic deazapurine nucleosides and pronucleotides
Perlíková, Pavla ; Hocek, Michal (advisor) ; Jindřich, Jindřich (referee) ; Hlaváč, Jan (referee)
The synthetic routes to three types of phosphate prodrugs of 6-hetaryl-7-deazapurine ribonucleosides based on palladium-catalyzed cross-coupling reactions have been developed. CycloSal- and phosphoramidate pronucleotides and octadecyl phosphates derived from 6- hetaryl-7-deazapurine ribonucleosides were screened for their in vitro cytostatic activity. It was shown that cytostatic activity of cycloSal phosphates was similar or slightly lower compared to the parent nucleosides. Significant drop of cytostatic activity was observed in phosphoramidate pronucleotides. Octadecyl phosphates were devoid of any cytostatic activity. 6-Hetaryl-7-deazapurine ribonucleosides with bulky groups in position 6 showed very strong and selective inhibition of adenosine kinase from Mycobacterium tuberculosis. 2'-Modified 6-hetaryl-7-deazapurine nucleosides: 2'-O-methylribonucleosides, arabinonucleosides and 2'- deoxy-2'-fluororibonucleosides, were prepared by multistep functional group transformations from a ribonucleoside. The synthesis of 2'-deoxy-2',2'-difluoro-erythro-pentofuranosyl nucleosides was based on a glycosylation of 6-chloro-7-deazapurine with a sugar synthon followed by palladium-catalyzed cross-coupling reaction and deprotection. Despite the low yields and laborious separation of the anomers,...
New amphiphilic prodrugs of adefovir and cidofovir
Tichý, Tomáš ; Andrei, G. ; Dračínský, Martin ; Holý, Antonín ; Balzarini, J. ; Snoeck, R. ; Krečmerová, Marcela
New adefovir (PMEA) prodrugs with a pro-moiety consisting of decyl(oxyethyl) chain bearing hydroxyl function(s), hexaethyleneglycol or a (5-methyl-2-oxo-1,3-dioxolen-4-yl)methyl unit were prepared from the tetrabutylammonium salt of the phosphonate drug and an appropriate alkyl bromide or tosylate. Analogously, two esters of Cidofovir [(S)-HPMPC] bearing a hexaethyleneglycol moiety were prepared. The antiviral activity of the prodrugs was evaluated in vitro. A loss in the antiviral activities of the hydroxylated decyl(oxyethyl) esters and hexaethyleneglycol esters of PMEA against HIV and herpesviruses. (S)-HPMPC prodrugs exhibited anticytomegalovirus activities in the same range as the parent drug, whereas the anti-HSV and anti-VZV activities were one- to seven-fold lower than that of Cidofovir.