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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

Total synthesis of oxygenated lavendamycin analogs

Karki, Rajesh January 1998 (has links)
The synthesis of 7-acetyl-11'-benzyloxylavendamycin methyl ester (47), 7acetyl-11'-hydroxylavendamycin methyl ester (48), 11'-hydroxylavendamycin methyl ester (49), 11'-benzyloxylavendamycin methyl ester (50), are described. Pictet-Spengler condensation of 7-N-acetyl-2-formylquinoline-5,8-dione (26) with 5-benzyloxytrytophan methyl ester (45) or 5-hydroxytryptophan methyl ester (46) in dry xylene or anisole directly afforded lavendamycin analogs 47 or 48. Compound 49 was obtained by hydrolysis of 48 with 70% H2SO4 - H2Osolution. Compound 50 was obtained by hydrolysis of 47 with sodium carbonate solution.Aldehyde 26 was prepared according to the following general procedure. Nitration of 8-hydroxy-2-methylquinoline (28) yielded 8-hydroxy-2-methyl5,7-dinitroquinoline (29). Compound 29 was then hydrogenated and acylated with acetic anhydride to yield 5,7-bis(diacetamido)-8-hydroxy-2methylquinoline (31). Compound 31 was oxidized to give 5,8- dione 25 by using potassium dichromate. Treatment of compound 25 with selenium dioxide in refluxing 1,4-dioxane yielded compound 26.3 (Isopropylaminoethylidene)-6,7-dimethoxyindole (39) was prepared via the following procedure. Acylation of vanillin (32) with acetic anhydride yielded acetylvanillin (33). Compound 33 was nitrated and hydrolyzed to give 2nitrovanillin (35). Compound 35 was then methylated using dimethyl sulfate to produce 2-nitroveratric aldehyde (36). Condensation of compound 36 with nitromethane yielded 3,4-dimethoxy-2-f3-nitrostyrene (37). Ammonium formate reductive cyclization of compound 37 in refluxing methanol in the presence of a catalytic amount of 10% palladium on charcoal yielded 6,7dimethoxyindole (38). Electrophilic substitution reaction of compound 38 with ethylideneisopropylamine (41) in dry toluene yielded compound 39.Methyl (2RS, 3SR)-2-amino-3-[3-(5-benzyloxyindolyl)]butanoate (45) and methyl (2RS, 3SR)-2-amino-3-[3-(5-hydroxyindolyl)]butanoate (46) were obtained following the procedure described below. Electrophilic substitutionreaction of 5-bezyloxyindole (40) with ethylideneisopropylamine (41) in dry toluene yielded 3-(isopropylaminoethylidene)-5-benzyloxyindole (42). Condensation of compound 42 with methyl nitroacetate (43) in dry toluene gave methyl 3-[3-(5-benzyloxyindolyl)]3-nitrobutanoate (44). Hydrogenation of compound 44 in the presence of Raney nickel and trifluoroacetic acid in ethanol yielded methyl (2RS, 3SR)-2-amino-3-[3-(5-benzyloxyindolyl)] butanoate (45). Hydrogenation of compound 44 in the presence of 10% palladium on charcoal and trifluoroacetic acid in ethanol yielded methyl (2RS, 3SR)-2-amino-3-[3-(5-hydroxyindolyl)] butanoate (46).The structures of the novel compounds were confirmed by 1H NMR, IR, and HRMS or elemental analysis. / Department of Chemistry
2

Novel synthesis of quinoline-5,8-dione analogues

Teitgen, Alicen M. 21 July 2012 (has links)
The chemistry of quinonline-5,8-dione as a functional group is a developing field because of its various biological aspects. Lavendamycin and streptonigrin are known antibiotic, antitumor agents containing the quinolone-5,8-dione functional group believed to provide their antitumor properties. Most cancer cells show an elevated level of NQO1 enzyme which activates lavendamycin to act as an antitumor agent. The research goal is to explore different synthetic methods and reactions to produce novel quinolone-5,8-dione analogues with unique structural features while keeping the selective cytotoxicity. Lavendamycin contains a β-carboline and streptonigrin has a substituted pyridine connected to the 2-position of the quinolone-5,8-dione. The overall goal of this project will develop synthetic methods to create 1,2,3-triazoles and 1,2-diazoles attached to the quinoline moiety from azides and diazonium salts, respectively. In order to accomplish this, 8-hydroxyquinoline undergoes through a four step synthesis to install an azide at the two position of the quinoline ring. 8-Hydroxyquinoline was oxidized to produce 8-hydroxyquinoline-N-oxide, converted into 8-acetoxy-2-hydroxyquinoline with acetic anhydride, reacted with POCl3 to produce 2-chloro-8-hydroxyquinoline, and treated with sodium azide to form 2-azido-8-hydroxyquinoline. However it was found that the product cyclized to yield 8-hydroxy-tetrazole[1,5-a]quinoline. In the quinoline-5,8-dione synthesis, 7-amidoquinoline-5,8-dione is prepared through a three step synthesis. 8-Hydroxquinoline was nitrated to form 8-hydroxy-5,7-dinitroquinoline, hydrogenated/acylated to give 5,7-diacetamido-8-acetoxyquinoline, and oxidized to yield 7-acetamidoquinoline-5,8-dione. In order to reach the end of this project, the four step tetrazole and the three step quinoline-5,8-dione syntheses required merging. Further research will focus on the optimization of these syntheses. / Synthesis of 8-hydroxy-tetrazole [1,5-a] quinoline -- Synthesis of 7-amino-quinoline-5,8-dione -- Novel synthesis of quinoline-5,8-dione analogues. / Department of Chemistry
3

Total synthesis of lavendamycin amides

Lineswala, Jayana P. January 1996 (has links)
The synthesis of 7-N-acetyldemethyllavendamycin butyl amide (47), 7-Nacetyldemethyllavendamycin isopropyl amide (48), 7-N-acetyldemethyllavendamycin amide of piperidine (49), 7-N-acetyldemethyllavendamycin amide of pyrrolidine (50), 7N-acetyldemethyllavendamycin amide of morpholine (51), demethyllavendamycin butyl amide (52), demethyllavendamycin amide of pyrrolidine (53), and demethyllavendamycin amide of morpholine (54) are described. Pictet Spengler condesation of 7-acetamido-2formylquinoline-5,8-dione (28) with tryptophan butyl amide (66), tryptophan isopropyl amide (67), tryptophan amide of piperidine (68), tryptophan amide of pyrrolidine (69), and tryptophan amide of morpholine (70) in an anisole - pyridine solution directly afforded the five lavendamycin amides 47-51. Compounds 52, 53, and 54 were obtained by hydrolysis of 47, 50, and 51 with 70% H2SO4-H20 solution.Aldehyde 28 was prepared according to the following general procedure.Nitration of 8-hydroxy-2-methylquinoline (30) yielded 8-hydroxy-2-methyl-5,7 dinitroquinoline (31). Compound 31 was then hydrogenated and acylated with acetic anhydride to yield 5,7-diacetamido-2-methyl-8-acetoxyquinoline (33). Compound 33 was oxidized by potassium dichromate to give 7-acetamido-2-methylquinoline-5,8-dione (27). Treatment of 27 with selenium dioxide in refluxing 1,4-dioxane afforded compound 28.Compounds 66, 67, 68, 69, and 70 were synthesized from compounds 61,62, 63, 64, and 65. These compounds were deprotected with ammonium formate in the presence of 10% Palladium on charcoal in methanol under an argon balloon at atmospheric pressure.Compounds 61, 62, 63, 64, and 65 were obtained from 58 with butylamine, isopropylamine, piperidine, pyrrolidine, and morpholine respectively in the presence of triethylamine under an argon balloon at atmospheric pressure.Compound 58 was synthesized by the reaction of N-carbobenzyloxytryptophan, with N-hydroxy succinimide, in the presence of N-dicyclohexylcarbodimide in dried and distilled dioxane under an argon balloon at atmospheric pressure.The structures of the novel compounds 58, 47, 48, 49, 50, 51, 52, 53, and 54 were confirmed by 1H NMR, IR, EIMS, and HRMS.The structures of protected and deprotected amides 61, 62, 63, 64, 65, 66, 67, 68, 69, and 70 were also confirmed by 1 H NMR and IR spectroscopy. / Department of Chemistry

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