Steroidal tetraoxanes: synthesis and biologycal activity

U toku izrade ove doktorske disertacije sintetisani sutetraoksani derivata holne kiseline i ispitana je njihovaantimalarijska, citotoksična i antiproliferativna aktivnost. Utoku rada dobijeni su sledeći rezultati:1. Razvijena su dva postupka za sintezu bis-steroidnihtetraoksana: 1) direktna peroksiacetalizacijaodgovarajućih 3-keto derivata holne kiseline, 2)derivatizacija prethodno dobijenih bis-steroidnihtetraoksana. Primenom oba postupka sintetisano je 14bis-steroidnih tetraoksana derivata holne kiseline, 123-136. Prema prvom postupku sintetisani su bis-steroidnitetraoksani 123 - 128. Proizvodi 123 i 124 dobijeni sureakcijom ketona 119 sa 30% H2O2 / 50% H2SO4, uprinosu od 25% i 28%, a proizvodi 125 - 128 ureakcijama ketona 121 i 122 sa (Me3Si)2O2 / TMSOTf,na 0 oC u prinosu 28 – 50% (Shema 24). Utvrđeno je dau reakcijama ketona 119 sa (Me3Si)2O2 / TMSOTf i 121 i122 sa 30% H2O2 i 50% H2SO4 dominantno nastajuproizvodi Baeyer – Villiger-ove reakcije. Prema drugompostupku sintetisani su tetraoksani 127– 136124 na dva načina: a) hidrolizom 1,25 M rastvoromNaOH u smeši CH2Cl2 / MeOH na sobnoj temperaturi utoku 3 dana (72 – 79%); b) hidrolizom pomoću NaOH usmeši i-PrOH / H2O (3:1, v/v) na temperaturi ključanja utoku 15 min. (90 – 95%, Shema 24). Kiseline 129 i 130prevedene su preko mešovitog anhidrida u amide 131 –136 (54 – 81%) kao i prethodno sintetisane amide 127 i128 (Shema 25). Izolovana su oba predviđenadiastereomera a na osnovu spektralnih podataka ianalize monokristala derivata 123 X-zracima, pripisanaje struktura sintetisanim derivatima: cis-C(2)C(2a) serijipripadaju derivati 123, 125, 127, 129, 131, 133 i 135, atrans-C(2)C(2a) seriji pripadaju derivati 124, 126, 128,130, 132, 134 i 136.2. Razvijen je postupak za sintezu gem-dihidroperoksidaderivata holne kiseline (137, 145 i 146, Shema 29) kojiuspešno može da se primeni i za dobijanje gemdihidroperoksidajednostavnih cikličnih ketona (149, 150i 76, Shema 30). Gem-dihidroperoksidi su sintetisanireakcijom odgovarajućeg ketona i 30% H2O2 u smešiCH2Cl2 / CH3CN (1:3, v/v) u prisustvu katalitičkih količinakonc. HCl u visokom prinosu (> 90%). Postupak razvijenu toku ovog rada je jednostavniji, ekonomičniji i bitnopoboljšan u odnosu na postupke do sada opisane uliteraturi (ref. 45, 47, Shema 13).3. Sintetisana su 53 mešovita tetraoksana derivata holnekiseline, 138 – 144b. Metil-estri 138 dobijeni sukuplovanjem gem-dihidroperoksida 137 sajednostavnim, supstituisanim i nesusptituisanim,cikličnim ketonima (~ 30%, Shema 27). Reakcija se vršiu dihlormetanu, u prisustvu katalitičkih količina H2SO4.Reakcijom ciklopentanona, cikloheksanona iciklooktanona dobijen je i izolovan po jedan proizvod, asvaki od prohiralnih 4-metil-, 4-etil-, 4-t-butil- i 4-fenilcikloheksanonadaju oba očekivana diastereoizomera.Reakcijama 2,6-dimetil-, 2-metil-cikloheksanona i. mentona proizvodi su izolovani u obliku odgovarajućihsmeša. Reakcija gem-dihidroperoksida 137 saaromatičnim karbonilnim jedinjenjima - 2-furil-metilketon,4-nitroacetofenon, 6-metoksitetralon-1-on i pmetoksibenzaldehid- nije dala očekivane proizvode.Selektivnom hidrolizom C(24) metil-estarske grupetetraoksana 138 sa NaOH u smeši i-PrOH / H2O (3:1,v/v) na temperaturi ključanja dobijene su odgovarajućekarboksilne kiseline 139 (72 – 93%), koje su prekomešovitog anhidrida prevedene u odgovarajuće amide140 – 144b (~ 80%, Shema 28). Na osnovu spektralnihpodataka i analize monokristala kiseline 139g X-zracimaodređena je konfiguracija C(4”) atoma 4”-metil derivata.Utvrđeno je da derivati 138f, 139f i 140f – 143fpripadaju (4”R) seriji, a da derivati 138g, 139g i 140g –143g pripadaju (4”S) seriji...Within this thesis a cholic acid-derived 1,2,4,5-tetraoxacyclohexanes (tetraoxanes) were synthesised andcharacterised, their in vitro antimalarial activity wasevaluated and cytotoxicity determined. In addition, thetetraoxanes reported in this thesis were evaluated aspotential antiproliferatives against various cancers cell lines.The results can be summarised as follows:1.Two procedures for preparation of bis steroidaltetraoxanes were developed: 1) directperoxyacetalisation of the corresponding 3-keto cholicacid derivatives, 2) transformation of the previouslyprepared tetraoxanes into its derivatives. 14 bis-Steroidal tetraoxanes, 123-136, were prepared utilisingboth procedures. Tetraoxanes 123-128 were obtainedaccording to the first procedure. Compounds 123 and124 were prepared by reacting of ketone 119 with 30%H2O2 / 50% H2SO4 in 25% and 28% yield, respectively,while the compounds 125-128 were obtained from theketones 121 and 122 using TMS2O2 / TMSOTf at 0 oC,in 28-50% yield (Scheme 24). Ketone 119 with TMS2O2 /TMSOTf, as well as ketones 121 and 122 with 30%H2O2 / 50% H2SO4, afforded as main products theBaeyer-Villiger products. Procedure 2) was utilised forpreparation of tetraoxanes 127-136. The carboxylicacids 129 and 130 were obtained by selective hydrolysisof C(24) methyl ester moiety of tetraoxanes 123 and124, respectively, utilising a) hydrolysis with 1.25 MNaOH/CH2Cl2-CH3OH at r.t. for 3 days (72-79%), and b)hydrolysis with NaOH / i-PrOH-H2O (3:1, v/v) at reflux for15 min (90-95%, Scheme 24). The acids 129 and 130were further transformed via their mixed anhydrides intocorresponding amides 131-136 (54-81%), as well as intopreviously synthesised amides 127 and 128 (Scheme25). Both predicted diastereomers were isolated andtheir structures was assigned from correspondingspectral data and confirmed by X-ray analysis oftetraoxane 123 monocrystal: compounds 123, 125, 127,129, 131, 133, and 135 belong to cis-C(2)C(2a) series,and to corresponding trans-C(2)C(2a) series belong thecompounds 124, 126, 128, 130, 132, 134, and 136.2. The procedure developed for the synthesis of cholicacid-derived gem-dihydroperoxides (137, 145, 146,Scheme 29) was also applied for synthesis gemdihydroperoxidesof simple cyclic systems (149, 150 and76, Scheme 30). It embodies the treatment of a ketonewith 30% H2O2 in CH2Cl2-CH3CN mixture (1:3, v/v) in thepresence of cat. HCl (> 90%). The procedure developedwithin this thesis represents a significant improvement interms of simplicity and economy as compared with theknown ones (ref. 45, 47, Scheme 13).3. 53 Mixed tetraoxanes derived from cholic acid wereprepared (138-144b). Mixed steroidal tetraoxane methylesters 138 were synthesised by coupling of gemdihydroperoxide137 to simple substituted and nonsubstitutedcycloalkanones (~30%, Scheme 27). Thecoupling reaction was performed in dichloromethane inthe presence of cat. H2SO4. The reaction ofcyclopentanone, cyclohexanone and cyclooctanoneafforded only one corresponding tetraoxane each, whilethe reaction of 4-methyl, 4-ethyl, 4-t-butyl, and 4-phenylcyclohexanone afforded both expecteddiastereomers each. Aromatic ketones failed to producea tetraoxane in a reaction with the samedihydroperoxide. Selective hydrolysis of tetraoxanes 138with NaOH / i-PrOH-H2O as above afforded thecorresponding acids 139 (72-93%), which were via theirmixed anhydrides transformed into correspondingamides 140-144b (~80%, Scheme 28). Theconfiguration at C(4") in 4"-methyl series wasdetermined by X-ray analysis of tetraoxane acid 139g. Itis found that tetraoxanes 138f, 139f, and 140f-143fbelong to (4"R)-series, while their respective (4"S)diastereoisomers are 138g, 139g, and 140g-143g..