The synthesis of an internal standard for bicalutamide
| dc.contributor.advisor | Van der Westhuizen, J. H. | |
| dc.contributor.advisor | Bezuidenhout, B. C. B | |
| dc.contributor.author | Jordaan, Maryam Amra | |
| dc.date.accessioned | 2016-12-01T10:17:57Z | |
| dc.date.available | 2016-12-01T10:17:57Z | |
| dc.date.issued | 2008-01 | |
| dc.description.abstract | English: (R,S)-Bicalutamide [N-(4-cyano-3-trifluoromethylphenyl)-α-methyl-α-hydroxy-β-(4- fluorophenylsulfonyl)propanamide], sold as Casodex®, is the leading antiandrogen currently used to treat prostate cancer. It binds to androgen receptors and blocks cancer growth.This work aims to develop internal standards for the bio-analytical component of clinical trials that are required to detect bicalutamide and derivatives. An internal standard is added to the body fluid sample (mostly blood) at the beginning of the sample work up at about the same concentration of the analyte to be quantified. An ideal internal standard has a similar extraction recovery and a similar retention time in HPLC. For quantification with mass spectrometry it should have a difference of at least 3 mass units from the analyte and a similar ionization response. The internal standard is used to calibrate the total ion current of the metabolite. We did not have access to deuterium labeled starting materials and investigated structural analogues as an alternative strategy to obtain internal standards. De novo synthesis of structural analogues failed because we could not deprotonate the methyl sulfone in the presence of aromatic amides. We ascribed this to incomplete disclosure in the patented methods.Treatment of bicalutamide with palladium on activated charcoal under the right conditions did not give the usually produced amide but gave smooth reduction of the C≡N group to a CH3 group. This unusual reduction gave ready access to a good internal standard in good yield.Elimination of the tertiary aliphatic hydroxy group of bicalutamide would give an alkene with similar polarity that could serve as an internal standard. Acid catalysisusing 1M HCl or p-toluene sulfonic acid failed, but treatment of bicalutamide with H2SO4 in benzene gave hydrolysis of the nitrile to an amide. This provides a second internal standard in good yield. Bicalutamide did not react with weak base. Strong base such as LDA led to fission of the aliphatic moiety and isolation of aromatic sulfone and amide fragments. Derivitization of the tertiary aliphatic hydroxy group of bicalutamide with 3- nitrobenzoyl chloride gave a benzoyl ester that allows facile thermal elimination of nitrobenzoic acid at 40 ºC to form an alkene. This represents a third potential internal standard. The NOESY experiment proves that the alkene has a Z-configuration. This indicates that the pro-R aliphatic hydrogen of bicalutamide was eliminated stereoselectively via a syn-periplanar cyclic transition state. Efforts to eliminate the hydroxy group of bicalutamide photolytically at 300 nm in ethanol yielded an unexpected replacement of the aromatic CF3 group with an ethoxy group. We could not find a similar transformation in the literature and believe it to be a novel reaction. We used 19F NMR to prove the absence or presence of fluorine and CF3 moieties in the products. We also used the magnitude of 13C-19F coupling constants in proton decoupled 13C spectra for accurate resonance assignment and structure elucidation.We will test these novel analogues of bicalutamide in cancer bioassays and use them as internal standards for the quantification of bicalutamide and analogues in body fluids. | en_ZA |
| dc.description.abstract | Afrikaans: (R,S)-Bicalutamide [N-(4-siano-3-trifluorometielfeniel)-α-metiel-α-hydroksi-β-(4- fluorofenielsulfoniel)propaanamied], wat verkoop word onder die handelsnaam Casodex®, word beskou as een van die belangrikste anti-androgene middels wat tans gebruik word om prostraatkanker te behandel. Dit bind met androgene reseptore en inhibeer kanker groei.Hierdie navorsing beoog om interne standaarde te ontwikkel vir die bio-analitiese komponent van kliniese studies wat vereis word om bikalutamied en derivate te registreer. ‘n Interne standard word aan die begin van die opwerk van die liggaamsvloeistofmonsters (meestal bloed) bygevoeg teen ongeveer dieselfde konsentrasie as die analiete wat gekwantifiseer moet word. Die ideale interne standaard ekstraëer teen ‘n soortgelyke konsentrasie en het ongeveer dieselfde retensietyd in HPLC as die analiet. Vir kwantifisering met massaspektrometrie moet daar ‘n verskil van ten minste 3 massa-eenhede en ‘n soortgelyke ionisasie reaksie in vergelyking met die analiet wees. Die interne standaard word gebruik om die totale ioon-vloei van die metaboliete te kalibreer.Ons het nie toegang gehad tot gedeutereerde uitgangstowwe nie en het strukturele analoë ondersoek as ‘n alternatiewe strategie om interne standaarde daar te stel. De novo sintese van strukturele analoë het gefaal aangesien ons nie die metielsulfone kon deprotoneer in die teenwoordigheid van aromatiese amiede nie. Ons het dit toegeskryf aan onvolledige inligting in die gepatenteerde metodes.Behandeling van bikalutamied met palladium op geaktiveerde koolstof onder die regte toestande het nie die gewone amied geproduseer nie, maar het geredelik die C≡N-groep na ‘n CH3-groep gereduseer. Hierdie ongewone reduksie gee in ‘n goeie opbrengs gerieflike en maklike toegang tot ‘n interne standaard. Eliminasie van die tersiêre alifatiese hidroksielgroep van bikalutamied behoort alkene met ‘n polariteit soortgelyk aan dié van die analiet te lewer wat as interne standaard kan dien. Suurkatalise (HCl (1 M) of p-tolueensulfoonsuur) het gefaal, maar behandeling van bikalutamied met H2SO4 in benseen het die nitriel na ‘n amied gehidroliseer, wat ‘n tweede interne standaard in ‘n goeie opbrengs lewer. Bikalutamied het nie met ‘n swak basis reageer nie, maar sterk basisse soos LDA het tot splyting van die alifatiese moeïeteit en isolasie van aromatiese sulfone en amiedfragmente gelei.Derivatisering van die tersiêre alifatiese hidroksielgroep van bikalutamied met 3- nitrobensoïelchloried het ‘n bensoïelester gelewer wat teen 40 oC fasiele termiese eliminasie van nitrobensoësuur toelaat om ‘n alkeen te vorm. Dit verteenwoordig ‘n derde potensiële interne standaard. NOESY eksperimente het bewys dat die alkeen ‘n Z-konfigurasie het, wat toon dat die pro-R alifatiese waterstof (en nie die pro-S alifatiese waterstof) van bikalutamied stereochemies geëlimineer is via ‘n synperiplanêre sikliese transisie toestand.Pogings om die hidroksielgroep van bikalutamied fotolities teen 300 nm in etanol te elimineer, het ‘n onverwagse vervanging van die aromatiese CF3-groep met ‘n etoksiegroep teweeggebring. Ons kon geen soortgelyke transformasie in die literatuur opspoor nie en glo dat dit ‘n unieke en nuwe reaksie is.Ons het van 19F KMR gebruik gemaak om die teenwoordigheid of afwesigheid van fluoriede en CF3- moeïeteite in ons produkte aan te dui. Die groottes van die 13C-19F koppelingskonstantes in ons proton-ontkoppelde 13C KMR spektra lei tot die akkurate toekenning van resonansies en struktuuropklaring.Ons sal hierdie nuwe analoë van bikalutamied in kanker bio-assesering toets en as interne standaarde gebruik vir die kwantifisering van bikalutamied en analoë in liggaamsvloeistowwe. | af |
| dc.identifier.uri | http://hdl.handle.net/11660/5141 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | University of the Free State | en_ZA |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | Dissertation (M.Sc. (Chemistry))--University of the Free State, 2008 | en_ZA |
| dc.subject | Antiandrogens | en_ZA |
| dc.subject | Drugs -- Analysis | en_ZA |
| dc.subject | Medicine -- Research | en_ZA |
| dc.title | The synthesis of an internal standard for bicalutamide | en_ZA |
| dc.type | Dissertation | en_ZA |