This research is part of a long-term project aimed at elucidating important structural features, of both ligands and metals, that are needed to produce effective anti-cancer agents. The specific goal is the synthesis of organotin polymers containing amino acids, in this case the diamino acid diglycine. The desired materials were synthesized with percent yields ranging from 32-99%. The products were synthesized employing the interfacial polymerization technique. The polymers were then characterized utilizing the following physical characterization techniques: light scattering photometry (LS), Infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), and matrix assisted laser desorption mass spectroscopy (MALDI). Physical characterization showed evidence of formation of desired adducts in addition to data that was consistent with the formation of materials containing multiple repeat units. The materials were then analyzed for biological activity. The synthesized materials displayed the ability to inhibit tested cancer cell lines. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

This thesis reports on the feasibility of the utilization of organotin hydrides as enaantioselective free radical reducing agents. The chiral organotin hydrides prepared contain the bulky chiral (1R,2S,5R)-menthyl substituent and in some cases also contain a stereogenic tin centre. Reaction of (1R,2S,5R)-menthylmagnesium chloride (MenMgC1) with triphenyltin chloride in THF proceeds with epimerization of the C-1 carbon of the menthyl group and results in a mixture of (1R,2S,5R)-menthyltriphenyltin and (1S,2S.5R)-menthyltriphenyltin. Addition of Lewis bases such as triphenylphosphine to the THF solution of triphenyltin chloride prior to the addition of the Grignard reagent suppresses epimerization and enables isolation of pure (1R,2S,5R)-menthyltriphenyltin. (1R,2S,5R)-Menthyltriphenyltin is the precursor for the synthesis of (1R,2S,5R)-menthyldiphenyltin hydride as well as (1R,2S,5R)-menthyl-containing organotin halide derivatives. A crystal structure of (1R,2S,5R)-menthylphenyltin dibromide and (1R,2S,5R)-menthylphenyltin dichloride confirmed the configuration of the menthyl substituent in these compounds. Reaction of MenMgC1 with diphenyltin dichloride in THF proceeds with no epimerization of the C-1 carbon of the menthyl group and bis((1R,2S,5R)-menthyl)diphenyltin is formed. A crystal structure of (1R,2S,5R)-menthyltriphenyltin confirmed the configuration of the menthyl substituent. Bis((1R,2S,5R)-menthyl)diphenyltin is used to form bis((1R,2S,5R)-menthyl)phenyltin hydride as well as other bis(1R,2S,5R)-menthyl derivatives. A series of chiral non-racemic triorganotin halides and triorganotin hydrides containing one or two (1R,2S,5R)-menthyl substituents as well as various potentially intramolecular coordination substituents were synthesized and characterized. The intramolecular substituents include the 8-(dimethylamino)naphthyl, 2-[(1S)-1-dimethylaminoethyl]phenyl, 2-(4,4-dimethyl-2-oxazoline)-5-methylphenyl and the 2-(4-(S)isopropyl-2-oxazoline)-5-methylphenyl substituents. Each compound containing a stereogenic tin centre was synthesized as diastereomeric mixtures. AM1 calculations of these compounds provide good qualitative predictability of the molecular geometries observed in the solid state as well as the diastereomeric ratios observed in solution. X-ray analysis of some of the organotin halides containing intramolecular coordination substituents revealed a tendency towards penta-coordination at the tin centre as a result of N-Sn interactions. The chiral organotin hydrides synthesized were found to be poor enantioselective free radical reducing agents. However, the addition of one molar equivalent of achiral or chiral Lewis acids to the free radical reduction reactions involving these organotin hydrides results in remarkable increases in enantioselectivity. There are numerous examples in which enantioselectivities exceed 80% and three examples of enantioselectivites which are equal and above 90% with one outstanding enantioselective outcome of ≥99%. These results appear to be the highest enantioselectivites for organotin hydride radical reductions reported to date. There is strong evidence to suggest that the chiral menthyl group of the organotin hydride directs the stereochemical outcome in the reduced product. The results also suggest that an increase in the number of menthyl substituents attached to tin or the introduction of intramolecular coordination substituents does not necessarily results in a greater increase in enantioselectivity. Preliminary studies into the synthesis of organotin hydrides containing Lewis acid functionalities are also reported. A zirconium chloride functionality was found to be incompatible with organotin hydride. However, an organotin hydride containing a trialkylboron Lewis acid functionality attached via an alkyl chain was successfully synthesized. Although this reagent was only stable in the preparative THF solution, it was still found to be effective at reducing benzaldehyde to benzyl alcohol.

No description available.

Thesis (Ph. D.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

No description available.

This thesis describes the synthesis and chemistry of alkyl 2,3-bis(trimethylstannyl)-2-alkenoates ((78) and (83)). It was shown that these compounds could be readily transformed into useful intermediates for the synthesis of functionalized, stereochemically defined tetrasub-stituted alkenes (87) and tricyclic dienes of general structure (322A). The synthesis and chemistry of compounds (277) and (278) is also described. The palladium(O)-catalyzed addition of hexamethylditin to a variety of α,β-acetylenic esters (90), afforded in a stereoselective manner, the corresponding alkyl (Z)-2,3-bis(trimethylstannyl)-2-alkenoates (83). Subsequent thermolysis of these compounds afforded the corresponding alkyl (E)-2 , 3-bis(trimethylstannyl)-2-alkenoates (78). It was found that treatment of alkyl (E)- and (Z)-2,3-bis(tri-methylstannyl)-2-alkenoates with methyllithium at low temperature, followed by reaction of the resultant nucleophilic intermediate with a variety of alkylating agents, afforded the trisubstituted vinylstannanes (80). On the other hand, successive treatment of methyl w-halo-2,3-bis-(trimethylstannyl)-2-alkenoates (202) with methyllithium and HMPA provided a facile route to cyclic β-trimethylstannyl α,β-unsaturated esters (203). Compounds (80) were readily converted into vinyl iodides of general structure (219) in which W is a functionalized group derived from the CO₂R moiety. These latter compounds served as useful intermediates for the synthesis of functionalized, stereochemically defined tetrasubstituted alkenes (87). For example, treatment of compounds (219) with 1.1 or 2.2 equiv of n-butyllithium at -78°C afforded the corresponding vinyllithium species (86) , which could either be alkylated directly or further transposed into the organocopper(I) reagent (263A) and then alkylated, to afford in each case, the tetrasubstituted alkenes (87). The Pd(0)-catalyzed addition of tri-n-butylstannyltrimethylgermane (276) to a variety of α,β-acetylenic esters (90) afforded the corresponding compounds (277) and (278) in a ratio of approximately 3:1, respectively. Treatment of the (E) isomers (277) with n-butyllithium at -98°C, followed by alkylation of the resultant nucleophilic intermediate afforded the corresponding trisubstituted vinylgermanes (293). One of these latter compounds was readily converted into the iodo bromide (308), which is potentially synthetically equivalent to the d,a synthon (310). When the enolate anion of compounds (203) was successively treated with HMPA and compound (308) the esters (311) were obtained. The Pd(0) catalyzed intramolecular coupling of the vinylstannane-vinyl iodide moieties of (311) provided a facile route to the bicyclic triene esters (312). Similarly, alkylation of the enolate anion of compounds (203) with (325) (which was readily obtained from (203), in which n - 1), followed by the Pd(0)-catalyzed coupling of the resulting alkylated material afforded the tricyclic diene esters (322A). [Formula Omitted] / Science, Faculty of / Chemistry, Department of / Graduate

No description available.

Organotin compounds (OTs), in particular tributyltin (TBT) and triphenyltin (TPT), have caused widespread adverse effects on marine organisms ever since their wide application as biocides in 1960s. For instance, TBT can induce the abnormal development of imposex in marine gastropods, and inhibit development and growth in oysters. A mandatory global ban on the use of OT-based antifouling systems, therefore, has been enacted by the International Maritime Organization to minimize their environmental impacts since September 2008. As a result, it is anticipated to see a reduction of OT contamination in the marine environment around the world. This study, therefore, primarily aims to test the hypothesis that there is a reduction of both OT contamination and its associated adverse impact to a common biomonitor, the rock shell Reishia clavigera along the coast in Hong Kong and Shenzhen, China through a series of field-based investigations. Before the field study, a method was successfully developed to simultaneously quantify the concentrations of six common OTs (i.e., mono-BT, di-BT and TBT; mono-PT, di-PT and TPT) in molluscan tissues using gas chromatography-mass spectrometry. These six compounds coexist in marine environments. They are highly toxic to marine organisms and are able to induce imposex in gastropods like R. clavigera. First, a territory-wide survey on tissue concentrations of the OTs and imposex status in R. clavigera collected from 28 coastal sites of Hong Kong was conducted in 2010. The results indicated that all female R. clavigera suffered from imposex, and all rock shells contained high TPT concentrations. A probabilistic ecological risk assessment revealed that 17.6% of R. clavigera across all sites were at risk due to exposure to TPT, whereas the risk associated with TBT was relatively low. The same species collected from Dapeng Bay and Daya Bay, Shenzhen also exhibited high tissue concentrations of TPT. Second, R. clavigera transplanted from relatively clean sites to polluted sites for six months showed increases in both imposex status and tissue concentration of OTs, confirming the association between OT contamination and imposex development. Third, a 25-month population dynamics study of R. clavigera showed a limited recruitment of the species in the polluted sites. To verify if the observed OT contamination was widespread to other marine species in Hong Kong waters, a survey on the tissue concentrations of OTs in 11 local seafood species was conducted. Among them, the tongue sole Paraplagusia blochii had the highest tissue concentration of total OTs, with TPT as the most abundant residue. Potential health risk for consuming this benthic fish species was identified as both hazard quotient of TPT and hazard index exceeded unity. The overall results demonstrate that the coastal marine environments in this region are still heavily contaminated with OTs especially TPT, and there is no obvious sign of recovery of R. clavigera populations. Hopefully, with further scientific investigations, both Hong Kong and China governments will take appropriate management actions to control the use and release of these priority pollutants with a view to safeguarding the marine ecosystem and human health in this region. / HKU 3 Minute Thesis Award, 2nd Runner-up (2013) / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

In Part 1, the Diels-Alder adducts of trimethyl cyclopentadienylstannane (I.3) with maleic anhydride and fumaronitrile are prepared in 61% yield. The molecular structure of the adduct with maleic anhydride (1.6) is unequivocally established as 7-syn-trimethy1stannyl-endo- bicyclo[2.2.1]hept-5-enyl-2,3-dicarboxy1ic anhydride by single crystal X-ray structure analysis. In Part II, the high yield preparation of some new S-a1ky1-Saryl- N-p-toluenesu1fonylsu1foximines, by ruthenium tetroxide oxidation of the corresponding su1filimine, is described. Dehydrochlorination of S-chloroethy1-N-p-toluenesu1fonyl-S-p-toly1su1foximine and its S-phenyl analog with triethylamine gives the previously unknown N-p-to1uenesu1fony1- S-p-to1y1-S-viny1sulfoximine (II.17) and its S-phenyl analog. The Diels-Alder reaction of II.17 with a variety of 1,3-dienes and the known N-phtha1imido-S-p-tolyl-vinylsu1foximine (11.14) and the previously unreported S-p-nitropheny1-N-phtha1imido-viny1su1foximine (11.39) with cyclopentadiene are described. All of the reactions give mixtures of the possible adducts. The configuration of the major diastereomer (II.19d) of the adducts of II.14 with cyclopentadiene is known from a single crystal X-ray structure analysis. The structures of the other adducts are determined by ¹H NMR spectroscopic analysis. Chemical correlation of II.19d with the adducts of II.17 with cyclopentadiene confirm the assignment made by ¹H NMR. A competition Die1s-Alder reaction between II.17 and p-toly1-viny1sulfone shows that the vinylsulfoximine is more reactive. Sodium amalgam reduction of the cyclohexadienyl adducts of II.17 gives bicyclo[2.2.2Joctene and hydrazine in allyl alcohol reduction of adduct II.19d gives the corresponding sulfoxide II.20d.

Chapter 1 describes the reactivities of bisgermavinylidene [(Me 3SiN=RPh2)2C=Ge→Ge=C(PPh2=NSiMe 3)2] (25). With the use of CpMnCO2(THF), Mn2(CO)10 and group 11 metal halides, manganese-germavinylidene complexes and germavinylidyl group 11 metal complexes were prepared respectively. Radical reaction of 25 with 2,2,6,6-tetramethylpiperidine N-oxide affords [(Me3SiN=RPh2)2C=Ge(ONCMe2C 3H6CMe2)2] (40). Cycloadditon reactions of 25 were studied. The reaction of 25 with benzil, azobenzene or 3,5-di-tert-butyl-o-benzoquinone affords [(Me3SiN=PPh2)2C=Ge{O(Ph)C=C(Ph)O}] (41), [(Me3SiN=PPh2)2C=Ge( o-C6H4NHNPh)](42) and [(Me 3SiN=PPh2)2C=Ge=C-(PPh2=NSiMe 3)2] (44), respectively. The C=Ge bond of 25 can undergo cycloaddition reactions with Me3SiN 3, Me3SiCHN2 or AdNCO (Ad = adamantly) to give [(Me3SiN=PPh2)2CGeN(SiMe3)N=N] (46), [(Me3SiN=PPh2)2C-GeN=NCH-SiMe 3] (48) and [(Me3SiN=PPh2)2 CGeN(Ad)C-O] (47), respectively. Furthermore, 1,2-addition products of rhodium(I) and tin(IV) complexes were prepared from the reaction of 25 with (cod)RhCl and (nBu) 3SnN3, respectively. The syntheses of bimetallic chlorides [(Me3SiN=PPh2)2(GcCl)CMn(mu-Cl)]2 (51) and [(Me3SiN=PPh2)2(GeCl)CFeCl] (52) are also reported. / Chapter 2 concerns the reactivities of bis(iminophosphorano)methanide tin(II) chloride [HC(PPh2=NSiMe3)2SnCl] ( 79). The reactivity of the lone pair in 79 was studied. The reaction of 79 with benzil or 3,5-di-tert-butyl- o-benzoquinone gives the corresponding cycloaddition products. Treatment of 79 with NaN3 or AgOSO2CF3 affords the corresponding substituted heteroleptic stannylenes. The reaction of 79 with W(CO)5THF gives an adduct [HC(PPh 2=NSiMe3)2(Cl)Sn→W(CO)5] ( 81). Compound 79 reacts with Fe{N(SiMe3) 2}2 to afford [HC(PPh2=NSiMe3) 2Fe(mu-Cl)]2 (86). Moreover, treatment of 79 with LiC≡CPh gives [HC(PPh2=NSiMe3) 2C(Sn)=C(Ph)Sn(C≡CPh)2]2 (87). / Chapter 3 deals with the preparation and characterization of group 14 bis(thiophosphinoyl) metal complexes. The newly developed ligand [(S=PPr i2CH2)2-C5H 3N-2,6] (126) undergoes metalation with nBuLi or (nBu)2Mg to afford the lithium complex [Li{(S=PPri 2CH)(S=PPi2CH2)C 5H3N-2,6}(Et2O)] (127) and magnesium complex [Mg(S=PPri2CH)2C 5H3N-2,6] (128), respectively. 1,3-Distannylcyclobutane and 1,3-diplumbacyclobutane were prepared from treatment of 126 with M{N(SiMe3)2}2 (M Sn, Pb) by the amine-elimination reaction. Furthermore, compound 127 reacts with GeCl2.dioxane or SnCl2 to afford digermylgermylene Ge[GeCl2{(S=PPr i2CH)(S=PPri 2CH2)C5H3N-2,6}]2 ( 131) and ionic tin(II) complex [{C5H3N-2,6-(CH 2PPri2=S)(CHPPr i2=S)}SN+][SnCl3 -] (134), respectively. / Chapter 4 describes the conclusion of the first three chapters. The future works of the first three chapters were also reported. / This thesis is focused on four areas: (i) the reactivities of bisgermavinylidene; (ii) the reactivities of bis(iminophosphorano)methanide tin(II) chloride; (iii) the synthesis of group 14 bis(thiophosphinoyl) metal complexes and (iv) conclusions and future works. / Kan, Kwok Wai. / "Aug 2007." / Adviser: Kevin W. P. Leung. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1007. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.