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4-oxothiazolidine-2-alkylidene vinyl bromides and a,a-dibromo-2-methoxyacetophenone: precursors in synthetically useful transformations initiated by the rare halophilic attack of nucleophiles

dc.contributor.advisorBaranac-Stojanović, Marija
dc.contributor.otherPavlović, Vladimir
dc.contributor.otherOpsenica, Dejan
dc.creatorAleksić, Jovana
dc.date.accessioned2016-01-05T13:00:03Z
dc.date.available2016-01-05T13:00:03Z
dc.date.available2020-07-03T10:14:13Z
dc.date.issued2013-03-08
dc.identifier.urihttp://eteze.bg.ac.rs/application/showtheses?thesesId=1207
dc.identifier.urihttp://nardus.mpn.gov.rs/handle/123456789/3501
dc.identifier.urihttps://fedorabg.bg.ac.rs/fedora/get/o:8119/bdef:Content/download
dc.identifier.urihttp://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=45194511
dc.description.abstractHalofilne reakcije predstavljaju vrstu nukleofilnih supstitucionih reakcija do kojih dolazi kada nukleofil reaguje sa atomom halogena, nakon ega se oslobaa karbanjon kao odlazea grupa. To su relativno rijetke reakcije koje se dešavaju ukoliko je klasina nukleofilna supstitucija (karbofilna reakcija) iz nekog razloga otežana i/ili kada je karbanjon stabilizovan prisustvom elektron-privlanih supstituenata. Cilj ovog rada je bio da se ispitaju halofilne reakcije i njihova sintetika primena na dva sistema: 2-alkiliden-4-oksotiazolidin vinil-bromidima i ,-dibrom-2- metoksiacetofenonu. Znaaj ovih reakcija u sluaju ispitivanih N-nesupstituisanih tiazolidinskih jedinjenja je u dobijanju novih, potencijalno biološki aktivnih C-5 funkcionalizovanih derivata. Ovakvi derivati se ne mogu dobiti direktno reakcionom sekvencom C-5 bromovanje/nukleofilna supstitucija, jer je bromovanje Nnesupstituisanih 2-alkiliden-4-oksotiazolidina visoko regioselektivno i kao proizvodi se dobijaju iskljuivo vinil-bromidi. Znaaj prouavanja ovakvih reakcija u sluaju a,a- dibrom-2-metoksiacetofenona proistie iz injenice da se selektivno a- monobromovanje metil-ketona esto teško postiže, a praeno je stvaranjem a,a-dibromderivata kao sporednih, a ponekad i kao glavnih proizvoda. Mogua kaskadna halofilna/karbofilna reakcija bi omoguila korišenje dibrom-derivata kao sintetikih ekvivalenta monobromida, ime bi se izbegla dodatna faza selektivnog debromovanja radi dobijanja monobrom-derivata, kao znaajnih sintetikih intermedijera. Razliiti neutralni i anjonski nukleofili su uestvovali u halofilnoj reakciji sa tiazolidinskim vinilbromidima dajui tri vrste proizvoda: i) proizvod reduktivnog debromovanja, ii) proizvod supstitucije broma i iii) C-5 funkcionalizovan proizvod. Takoe je pokazano da se ,-dibrom-2-metoksiacetofenon može upotrebiti kao sintetiki ekvivalent a- monobromacetofenona. Pored navedenih halofilnih reakcija, u ovom radu ispitivana je i mogunost izvoenja Suzuki-Miyaura reakcije na vinil-bromidima, kao i mogua regioselektivnost ove reakcije na N-supstituisanom tribrompirazolu, a u cilju dobijanja novih, potencijalno biološki aktivnih jedinjenja. Suzuki-Miyaura reakcija sa derivatima arilbornih kiselina izvedena na vinil-bromidima nije dala oekivani rezultat, ali je uspešno izvedena sa N-supstituisanim tribrompirazolima uz visoku regioselektivnost, pri emu su sintetisani 5-supstituisani 3,4-dibrompirazoli sa 1,1 ekvivalentom arilbornih kiselina, 3,5-disupstituisani 4-brompirazoli sa 2,2 ekvivalenta arilbornih kiselina i 3,4,5- trisupstituisani derivati sa 3,5 ekvivalenata arilbornih kiselina. S obzirom da ispitivani tiazolidini spadaju u grupu push-pull alkena, kod kojih elektronska delokalizacija izmeu donorskih i akceptorskih grupa na dvostrukoj vezi ima znaajan uticaj na njihove osobine i hemijsku reaktivnost, uraena je i kvantifikacija push-pull efekta dvostruke veze.sr
dc.description.abstractHalophilic reactions are nucleophilic substitution reactions in which nucleophile attacks halogen atom with the carbanion acting as a leaving group. They are relatively rare and usually take place if the classic nucleophilic substitution (carbophilic reaction) is made difficult, and/or if the resulting carbanion is stabilized by electronwithdrawing substituents. The aim of the present work was to study halophilic reactions and their synthetic application on two systems: 2-alkylidene-4-oxothiazolidines vinyl bromides and ,-dibromo-2-methoxyacetophenone. The significance of the studied reactions in the case of N-unsubstituited thiazolidine compounds would be the synthesis of novel, potentially biologically active C-5 substituted derivatives. These derivatives are impossible to obtain directly by the C-5 bromination/SNC substitution reaction sequence, since bromination of N-unsubstituited 2-alkylidene-4-oxothiazolidines is highly regioselective, resulting in the formation of vinyl bromides as sole products. Significance of the studied reactions in the case of ,-dibromo-2- methoxyacetophenone arises from the fact that selective a-monobromination of methyl ketones of often difficult to achieve. ,-Dibromo derivatives can be formed as side products, or even as major ones. A possible cascade halophilic/carbophilic reaction would allow the use of dibromo derivatives as synthetic equivalents of monobromo compounds, thus avoiding the additional step, selective debromination, necessary to obtain synthetically useful monobromo derivatives. Various neutral and anionic nucleophiles underwent a halophilic reaction with thiazolidine vinyl bromides yielding three types of products: i) products of reductive debromination, ii) bromine susbtitution products and iii) C-5 functionalized products. It has also been shown that ,-dibromo- 2-methoxyacetophenone can be used as synthetic equivalent of a-monobromo acetophenone. Apart from the mentioned halophilic reactions, a possibility of Suzuki-Miyaura reaction to take place with the vinyl bromides was investigated, along with the possible regioselectivity of the same reaction applied to N-substituted tribromopyrazoles, all with the aim to obtaine new, potentially biologically active compounds. Suzuki-Miyaura reaction of vinyl bromides with aryl boronic acid did not give the expected tetrasubstituted alkenes. On the contrary, Suzuki-Miyaura reaction performed with the N-substituted tribromopyrazoles showed high regioselectivity yielding 5-substituted 3,4-dibromopyrazoles with 1.1 equivalent of aryl boronic acids, 3,5-disubstituted 4- bromo derivatives with 2.2 equivalents of aryl boronic acids and 3,4,5-trisubstituted derivatives with 3.5 equivalents of aryl boronic acids. Studied thiazolidine derivatives belong to the class of the so-called push-pull alkenes in which electronic delocalization beween donor and acceptor groups attached at the C=C double bond highly influences their properties and chemical reactivity. For this reason, one aim of the present work was also to quantify this push-pull effect of the studied compounds.en
dc.formatapplication/pdf
dc.languagesr
dc.publisherУниверзитет у Београду, Хемијски факултетsr
dc.rightsopenAccessen
dc.sourceУниверзитет у Београдуsr
dc.subjecthalofilne reakcijesr
dc.subjecthalophilic reactionsen
dc.subjectvinil-halogenidisr
dc.subject-dibromacetofenonisr
dc.subjectSuzuki- Miyaura reakcijasr
dc.subjectpush-pull efekatsr
dc.subjectNBO analizasr
dc.subjectvinyl halidesen
dc.subject-dibromoacetophenonesen
dc.subjectSuzuki- Miyaura reactionen
dc.subjectpush-pull effecten
dc.subjectNBO analysisen
dc.title4-oksotiazolidin-2-alkiliden vinil-bromidi i α, α-dibrom-2-metoksiacetofenon : prekursori u sintetički korisnim transformacijama iniciranim retkim halofilnim napadom nukleofilasr
dc.title4-oxothiazolidine-2-alkylidene vinyl bromides and a,a-dibromo-2-methoxyacetophenone: precursors in synthetically useful transformations initiated by the rare halophilic attack of nucleophilesen
dc.typedoctoralThesisen
dc.rights.licenseBY-NC-ND
dcterms.abstractБаранац-Стојановић, Марија; Опсеница, Дејан; Павловић, Владимир; Aлексић, Јована; 4-оксотиазолидин-2-алкилиден винил-бромиди и α, α-дибром-2-метоксиацетофенон : прекурсори у синтетички корисним трансформацијама иницираним ретким халофилним нападом нуклеофила; 4-оксотиазолидин-2-алкилиден винил-бромиди и α, α-дибром-2-метоксиацетофенон : прекурсори у синтетички корисним трансформацијама иницираним ретким халофилним нападом нуклеофила;
dc.identifier.fulltexthttp://nardus.mpn.gov.rs/bitstream/id/29714/Disertacija.pdf


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