No description available.

No description available.

No description available.

No description available.

Many naturally occurring and synthetically made azapolycyclic aromatic ring systems display important biological activities. One class of naturally occurring azapolycyclic aromatic ring systems is the dibenzopyrrocoline alkaloids, made from an indole nucleus fused to an isoquinoline system sharing the same nitrogen, i.e. the indolo[2,1-a]isoquinoline nucleus. The indolo[2,1-a]isoquinoline and its analogues have been reported to possess antileukemic, tubulin polymerization inhibitory and antitumor activity. A variety of indolo[2,1-a]isoquinolines have been synthesized in our labs. This includes, the 5,12-dimethyl-6-phenylindolo[2,1-a]isoquinoline, using the Suzuki- Miyaura cross-coupling reaction and reaction conditions for the formation of aromatic rings (KOBut in DMF) developed in our laboratories. In this dissertation, we outline the syntheses of (±)-5,6-dihydro-6-phenylindolo[2,1-a]isoquinolin-5-ol and 2-(1-benzyl-1H-benzo[d]imidazol-2-yl)benzaldehyde. We also discuss the synthesis and the modelling studies, (docked in silico) of the 3-substituted oxindoles in the X-ray crystal structure of the PfPK5 cyclin dependent kinase (CDK). The synthesis of indolo[2,1-a]isoquinolines started with N-protection of isatin and benzimidazole with a benzyl group to afford 1-benzylindoline-2,3-dione and 1- benzyl-1H-benzo[d]imidazole, respectively. The next step was the synthesis of the brominated compound, 1-benzyl-2-bromo-1H-indole, and the iodated compound, 1-benzyl-2-iodo-1H-benzo[d]imidazole. 1-Benzyl-2-bromo-1H-indole was synthesized by means of a functional group interconversion of the oxygen in the 3-position of isatin to two chlorine atoms initially, followed by removal of those chlorine atoms with activated zinc, followed by the conversion of the carbonyl of the oxindole to give a 2-bromoindole using POBr3. 1-Benzyl-2-iodo-1Hbenzo[ d]imidazole was synthesized in two ways. Firstly, 1-benzyl-1Hbenzo[ d]imidazole was exposed to LDA followed by iodinating the 2-position by 5 exposure of the intermediate to diiodoethane. The second method uses a halogenating method developed in our labs. 1-Benzyl-1H-benzo[d]imidazole was exposed to isopropylmagnesium chloride lithium chloride followed by I2. Having obtained the halogenated products, both sets of halogenated precursors were coupled with 2-formylphenylboronic acid using the Suzuki-Miyaura crosscoupling reaction to obtain the products, 2-(1-benzyl-1H-indol-2-yl)benzaldehyde and 2-(1-benzyl-1H-benzo[d]imidazol-2-yl)benzaldehyde in 98 and 67% yield, respectively. Aromatization of 2-(1-benzyl-1H-indol-2-yl)benzaldehyde occurred easily using tBuOK in DMF at room temperature to afford (±)-5,6-dihydro-6- phenylindolo[2,1-a]isoquinolin-5-ol in 75% yield (7:3 ratio of anti-: syn-) but exposing 2-(1-benzyl-1H-benzo[d]imidazol-2-yl)benzaldehyde to the same reaction conditions did not afford the desired product. Dehydrating (±)-5,6- dihydro-6-phenylindolo[2,1-a]isoquinolin-5-ol using methanesulfonyl chloride in CH2Cl2 was unsuccessful. Further attempts at dehydrating (±)-5,6-dihydro-6- phenylindolo[2,1-a]isoquinolin-5-ol were prevented due to time constraints. In the last part of the project, a library of 3-substituted oxindoles (13 molecules) was synthesized successfully and the compounds were docked in silico in the active site of an X-ray crystal structure of PfPK5, a cyclin dependent kinase of the Plasmodium falciparum, the agent causing the most severe form of human malaria. Eleven of the thirteen compounds were synthesized by condensation of oxindole and a suitable aldehyde in the presence of piperidine. The other two, 3- (propan-2-ylidene)indolin-2-one and 5,6-dimethoxy-3-(methylthio)indolin-2-one, were synthesized differently. 3-(Propan-2-ylidene)indolin-2-one was synthesized by reacting the oxindole with acetone in the presence of HCl and 5,6-dimethoxy- 3-(methylthio)indolin-2-one was synthesized following Gassman’s methodology. Two molecules scored well in the molecular modelling studies using the X-ray crystal structure of PfPK5, namely, (E/Z)-3-(3,4-dimethoxybenzylidene)indolin-2- one and (Z)-3-(4-hydroxybenzylidene)indolin-2-one. 6 In conclusion, we managed to synthesize (±)-5,6-dihydro-6-phenylindolo[2,1- a]isoquinolin-5-ol using the Suzuki Miyaura cross-coupling reaction and reaction conditions that lead to aromatization (tBuOK in DMF at room temperature) as key steps and 2-(1-benzyl-1H-benzo[d]imidazol-2-yl)benzaldehyde using the Suzuki- Miyaura cross-coupling reaction. A library of 3-substituted oxindoles was made and using molecular modelling were docked in silico into the crystal structure of the active site of PfPK5 with 2 compounds showing promise, for further studies.

PART I. The preparation of (-)-ibogamine (1) in fourteen steps from benzoquinone and in 10% overall yield is a powerful illustration of the value of the asymmetric Diels-Alder reaction as a starting point in a multistep synthesis. All four cycloadducts, 70, 77, 84 and 96, obtained with the (S)-BINOL-TiCl��� complex were found to have the same absolute configuration. Furthermore, they are in the same enantiomeric series that Mikami observed with 1,4-naphthoquinone using the same catalyst, lending confidence to future stereochemical predictions that may be made with this system. PART II. Three different routes for the synthesis of the hexahydroisoquinoline 98 met obstacles which defeated our approach to koumine. The Diels-Alder reaction of cyclic 1-azadienes 102 and 108 was abandoned due to the lack of reactivity of the dienes. An anionic oxy-Cope rearrangement of the azabicyclo[2.2.2]octane system caused mainly decomposition of the starting materials. Finally, an intramolecular [2+2] photocycloaddition generated "crossed", "straight" and hydroisoquinoline products in varying ratios, depending on the substituent pattern of the substrate, but this approach was not synthetically useful. The results from this last study may be valuable for predicting the regiochemical outcome of certain intramolecular photocycloadditions. / Graduation date: 2003

There is plenty of evidence from epidemiology studies supporting a link between certain components in the human diet and cancer incidence. It is estimated that 3-4 million annual cases of cancer could be prevented worldwide just by changing dietary habits. In parts of the world where vegetables and fruits constitute a large part of the diet, certain cancer incidences are markedly lower compared to Western countries. In particular, consumption of cruciferous vegetables is negatively associated with occurrence of certain cancers. One of the compounds from crucifers that is implicated in chemoprevention, is indole-3-carbinol(I3C), documented to inhibit tumor formation in several tissues in rodents, including the mammary tissue. I3C and is currently being evaluated in several clinical trials as a chemopreventive agent against breast cancer in humans. There are, however, some legitimate concerns regarding the use of Pure I3C since, depending upon conditions of administration, I3C can act as a promoter of hepatocarcinogenesis. Evidence is presented here that dietary I3C can promote and/or enhance liver tumor formation in rainbow trout (supporting earlier reports in literature) and the C57BL/6J mouse (enhancement in short-term pre-initiation exposure through lactational transfer, inhibition in a long-term post-initiation feeding study). I3C is also reported to promote in the rat liver model. A major concern associated with dietary I3C supplementation relates to its estrogenic effects as seen in trout and also its ability to induce certain cytochrome P-450s involved in procarcinogen activation. Biological effects of I3C are attributed to its acid condensation products. It was observed in this study that I3C acts through different mechanisms, including the Ah receptor-mediated and estrogenic pathways. Understanding of the role of I3C derivatives in beneficial and/or hazardous effects resulting from dietary exposure will be crucial in evaluating the promise of I3C as a chemoprevention agent. Questions pertaining to the risk/benefit of the use of dietary I3C supplementation for preventing estrogen-related diseases, without increasing the risk of promotion of hepatocarcinogenesis in humans, may depend on whether the mechanism(s) of action of I3C derivatives in humans is more like the adult mouse or the neonatal mouse, rat and trout. / Graduation date: 1998

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thèse doctorat : Pharmacie. Chimie thérapeutique : Université de Nantes : 2003. / Bibliogr. f. 188-195.

Thèse de doctorat : Synthèse organique : Metz : 2006. / Thèse soutenue sur ensemble de travaux. Bibliogr. p. 98 -108.