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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Obtenção de novos heterociclos derivados do ácido levulínico / Attainment of new heterocycles derived from levulinic acid

Frigo, Leandro Marcon 30 September 2013 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study describes the attainment of twenty three (23) bis-heterocycles derived from the Levulinic Acid: Bis-Pyrazoles (6a-k) by the reaction of cyclecondensation between the 3-(5-(trifluoromethyl)-4,5-dihydro-1H-pyrazol-3-il)propanohidrazidamand a series of replaced β-alcoxiviniltrifluorometilcetonas. 1,3,4-oxadiazole 2-5-disubstituted (8-11) by reactions like [4 + 1] [OCNN+C], through the reactions of cyclecondensation between the 3-(5-(trifluoromethyl)-4,5-dihydro-1H-pyrazol-3-yl)propanohidrazida with different orthoesters as well as with carbon disulfide. It was also produced hydrazides (16c-d, g-h e 17c-d, g-h) derived of synthesized pyrimidines, to be used as precursorsn in the synthesis of bis-heterocycles, derivatizated of the reaction of those with some β- Ketones alcoxiviniltrifluormetil. The bis-heterocycles were obtained by the ordinary methodology, with efficiency between 61-97%.It was also gotten other original compounds (3i-k, 5), used as precursors in this study. The structure of these synthesized compounds were confirmed by the data of RMN 1H, 13C, besides the data of mass spectrometry. / Este trabalho descreve a obtenção de 23 novos bis-heterociclos derivados do Ácido Levulínico: Bis-Pirazóis (6a-k) a partir da reação de ciclocondensação entre o 3-(5-(trifluorometil)-4,5-dihidro-1H-pirazol-3-il)propanohidrazida e uma série de β-alcoxiviniltrifluorometilcetonas substituídas; 1,3,4-oxadiazóis 2-5-dissubstituídos (8-11) via reações do tipo [4 + 1] [OCNN+C], através de reações de ciclocondensação entre a 3-(5-(trifluorometil)-4,5-dihidro-1H-pirazol-3-il)propanohidrazida com diferentes ortoésteres, bem como com dissulfeto de carbono. Foram produzidas ainda, hidrazidas( 16c-d, g-h e 17c-d, g-h) derivadas de pirimidinas sintetizadas, para serem utilizadas como precursores na síntese de bis-heterociclos, derivatizados da reação destas com algumas β-alcoxiviniltrifluormetil cetonas. Os bis-heterociclos foram obtidos por metodologia convencional, com rendimentos entre 61-97%. Foram obtidos ainda outros compostos inéditos (3i-k, 5) utilizados como precursores nesse trabalho. As estruturas dos compostos sintetizados foram confirmadas por dados de RMN 1H, 13C, além de dados de espectrometria de massas.
2

Synthesis of Polyaryl-substituted Bisquinazolinones with potential photophysical properties

Mmonwa, Mmakwena Modlicious 11 1900 (has links)
3,5-Dibromo-2-aminobenzamide was reacted with 1,3-cyclohexanedione derivatives in the presence of iodine as catalyst in toluene under reflux to afford novel 6,8-dibromo-2-[3-(2´-alkyl-1´,2´,3´,4´-tetrahydro-6´,8´-dibromo-4´-oxoquinazoline-2yl)propyl]quinazolin-4(3H)-ones in high yields. Suzuki-Miyaura cross-coupling of the latter with arylboronic acids in the presence of Pd(PPh3)2Cl2–Xphos catalyst complex and K2CO3 as a base in dioxane-water mixture (3:1, v/v) afforded the corresponding polyaryl-substituted bis-heterocycles in a single step operation. The resultant compounds were characterized using a combination of NMR (1H and 13C) and IR spectroscopic techniques, as well as mass spectrometry. The electronic absorption and emission properties of these polyaryl-substituted bis-heterocycles comprising 2,3-dihydroquinazolin-4(1H)-one and quinazolin-4(3H)-one moieties linked by a flexible carbon chain were measured in dimethylsulfoxide (DMSO) and acetic acid by means of UV-Vis and fluorescence spectroscopic techniques. The absorption spectra of the resultant polyaryl-substituted bis-heterocycles showed blue-shift in acetic acid and red-shift in DMSO, while their emission spectra are blue-shifted in DMSO and red-shifted in acetic acid. The 4-methoxy groups on aryl-substituents caused red shift on π‒π* transition of the aryl-substituents. Moreover, it was also observed that as the propyl linkage becomes more substituted, the absorption and emission intensities decrease. / Chemistry / M. Sc. (Chemistry)
3

Synthesis of Polyaryl-substituted Bisquinazolinones with potential photophysical properties

Mmonwa, Mmakwena Modlicious 11 1900 (has links)
3,5-Dibromo-2-aminobenzamide was reacted with 1,3-cyclohexanedione derivatives in the presence of iodine as catalyst in toluene under reflux to afford novel 6,8-dibromo-2-[3-(2´-alkyl-1´,2´,3´,4´-tetrahydro-6´,8´-dibromo-4´-oxoquinazoline-2yl)propyl]quinazolin-4(3H)-ones in high yields. Suzuki-Miyaura cross-coupling of the latter with arylboronic acids in the presence of Pd(PPh3)2Cl2–Xphos catalyst complex and K2CO3 as a base in dioxane-water mixture (3:1, v/v) afforded the corresponding polyaryl-substituted bis-heterocycles in a single step operation. The resultant compounds were characterized using a combination of NMR (1H and 13C) and IR spectroscopic techniques, as well as mass spectrometry. The electronic absorption and emission properties of these polyaryl-substituted bis-heterocycles comprising 2,3-dihydroquinazolin-4(1H)-one and quinazolin-4(3H)-one moieties linked by a flexible carbon chain were measured in dimethylsulfoxide (DMSO) and acetic acid by means of UV-Vis and fluorescence spectroscopic techniques. The absorption spectra of the resultant polyaryl-substituted bis-heterocycles showed blue-shift in acetic acid and red-shift in DMSO, while their emission spectra are blue-shifted in DMSO and red-shifted in acetic acid. The 4-methoxy groups on aryl-substituents caused red shift on π‒π* transition of the aryl-substituents. Moreover, it was also observed that as the propyl linkage becomes more substituted, the absorption and emission intensities decrease. / Chemistry / M. Sc. (Chemistry)

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