Ph. D. THESIS 2009

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Stereoisomerism of the oximes is a consequence of the spatial arrangement, relative to the rigid C=N bond, of the OH group belonging to the oxime moiety and of a substituent located at the carbon atom. Isomers cis and trans terms are replaced by isomers syn and anti in the molecules containing two oxime groups. They are denoted syn and anti relative to the orientation of the OH groups belonging to the oxime moieties to the same side or across of the axis that go through the C=N bonds. Dioximes represent an interesting class of organic compounds which exhibit both acidic and basic character within the same function [28]. In this respect, the oxime moiety might be pass for a supramolecular connector that can generate supramolecular structures through complementary hydrogen bonds involving dimeric or trimeric motif [30] or due to the lone electron pair of the nitrogen atom, which gave it a significant transition metals complexing capacity [29]. 2.2. Synthesis of syn and anti isomers The synthesis of bicyclo[3.3.1]nonane-3,7- dioxime 5 starting from dione 2 was an important route to create a synthon bearing two functionalized sites, critically required in macrocyclization reaction. The dioxime 5 of bicyclo[3.3.1]nonane-3,7-dione 2 has been already synthesized [7abc] but the reactions underwent with the obtaining of the mixture of syn and anti isomers of dioxime 5. In our case the synthesis of 5 was performed using an improved procedure of a method already described in the literature [33] (Scheme 7). CH3-COONa, H2O O O + 2H2N OH OH N MeOH, rt 2 5-syn 5-anti 27 N OH Scheme 7. Synthesis of bicyclo[3.3.1]nonane-3,7-dione dioxime 5 starting from dione 2 and hydroxylamine hydrochloride Bicyclo[3.3.1]nonane-3,7-dione 2 was treated with a large excess of hydroxylamine hydrochloride in the presence of sodium acetate at room temperature to give its dioxime 5 in good yields. It is worth mentioning that several attempts of synthesis following the literature data [33] failed, the yields being very low. In this light, the protocol was changed by adding the solution of hydroxylamine hydrochloride and sodium acetate in water to the
icyclo[3.3.1]nonane-3,7-dione solution in water/ethanol instead of being the other way around [33]due to the poor solubility of dione 2 in ethanol. As novelty, syn and anti isomers of 5 have been isolated for the first time by column chromatography. The static and dynamic stereochemistry of the isolated isomers and the possibilities to build up supramolecular architectures for each isomer by stereospecific H bonds interactions have been investigated. Stereochemistry of the dioximes Th e st er eo ch em ist r y o f t h ese d io xim e s is d iscu ssed a cco r d in g t o t h e p ecu lia r a xia l ch ir a lit y o f a lk y ly d en e cy clo a lca n es [3 4 ] wh ich is sim ila r t o t h a t o f cy clo h exa n o n e o xim e ( 5 , Sch e m e 8 ). N N HO HO HO N HO N 8 28 a OH N N N HO OH OH N aS aR N N HO OH aSaR aSaS aRaR (5-syn; unlike) 5-anti; like) b Sch e m e 8 Dioxime of bicyclo[3.3.1]nonane-3,7-dione (2) exhibits two chiral axis (the C=N bonds) and the syn isomer is an unlike form (aRaS), while the anti isomer is chiral (like isomer: aSaS and aRaR). Due to the rigid structure of the bicyclo[3.3.1]nonane skeleton these three stereoisomers are separable. The formation in the case of the anti isomer of homochiral dimers by enantiospecific recognition could have many applications in chiral
Page 1 and 2: “BABES-BOLYAI” UNIVERSITY CLUJ-
Page 3 and 4: General Introduction OUTLINE Part A
Page 5 and 6: 3.6.1. Dots 188 3.6.2. 3D structure
Page 7 and 8: Part A: Synthesis and Structural An
Page 9 and 10: H 3C H 3C O O O C C O O 1a O O C C
Page 11 and 12: The two forms are in equilibrium an
Page 13 and 14: Figu re 4 . Th e 13 C-NMR APT (CDCl
Page 15 and 16: set used , the anarmonicities that
Page 17 and 18: Figure 9. ORTEP diagram for the bic
Page 19 and 20: 1.5.1. Tetramethyl 3,7-dihydroxybic
Page 21 and 22: Table 7. The selected molecular par
Page 23 and 24: a b Figure 14. 1 H NMR spectrum (CD
Page 25 and 26: Figure 16. 13 C NMR spectrum APT (C
Page 27: Absorbance (a. u.) Absorbance (a.u.
Page 31 and 32: m u lt ip let a t a t δ ==1 .7 6 p
Page 33 and 34: Figure 22. 13 C NMR APT spectrum of
Page 35 and 36: Figure 24. NMR investigation of the
Page 37 and 38: (mol·l -1 ) syn 8.8 x10 -3 1.4373
Page 39 and 40: a b Figure 29. 3D FTIR spectra in s
Page 41 and 42: Figure 32. ORTEP diagram for the cy
Page 43 and 44: H2 … N3 = 1.839 Å H5 … N6 = 1.
Page 45 and 46: 2. Conclusions of the part A Differ
Page 47: 20. L. J. Bellamy, “Advanced in I
Page 50 and 51: 2. Experimental part: fabrication a
Page 52 and 53: 3 m 30 m a b Figure 4. Optical imag
Page 54 and 55: (NA 1.25) in phase-contrast (a) and
Page 56 and 57: was chosen instead of an aqueous on
Page 58 and 59: Our goal is to develope a lasser as
Page 60 and 61: Figure 15. a Optical image of gold
Page 62 and 63: the power as parameter exhibits a m
Page 64 and 65: a b Figure 21 a) Optical image of g
Page 66: 4.5.3. 3D structures The 3D structu
Page 69 and 70: Selected References 1. E. S. Wu, J.
Page 71: VIII. J. Bosson-Ehoomann, A. Mihut,

Ph. D. THESIS 2009

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