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Total synthesis of lavendamycin analogs

The syntheses of 7-N-chloroacetyllavendamycin methyl ester (55), 7-N-butyryllavendamycin methyl ester (56), 7-N-chloroacetyldemethyllavendamycin octyl ester (57), 7-N-butyryldemethyllavendamycin octyl ester (58), 7-N-chloroacetyldemethyllavendamycin isoamyl ester (59), and 7-N-butyryldemethyllavendamycin isoamyl ester (61) are described. Incorporation of the Pictet-Spengler condensation of 7-chloroacetamido-2-formylquinoline-5,8-dione (62) or 7butyramido-2-formylquinoline-5,8-dione (63) with B - methyltryptophan methyl ester (11), L-tryptophan octyl ester (64), or L-tryptophan isoamyl ester (65) in xylene directly afforded six lavendamycin analogs.The aldehydes 62 and 63 were prepared according to the following general procedure. Nitration of 8-hydroxy-2methylquinoline (66) yielded 8-hydroxy-2-methyl-5,772, and 73 are also included. 1H NMR and IR are provided compounds 67, and 71, and 1H NMR is provided for compound dinitroquinoline (67). Compound 67 was then hydrogenated and acylated with chloroacetic anhydride (or butyric anhydride) to yield 5,7-bis(chloroacet4mido)-8-hydroxy-2-methylquinoline (69) (or 5,7-dibutyramido-8-butyroxy-2 methylquinoline (71)).Compound 69 (and 71) was oxidized by potassium dichromate to give the corresponding 5,8-dione 70 (and 72). Treatment of 70 (and 72) with selenium dioxide in refluxing 1,4-dioxane afforded compound 62 (and 63). It was also noted that 71 would hydrolyze to its 8-hydroxy derivative 73 in hot methanol-water.Compound 64 was prepared through the neutralization of Ltryptophan octyl ester hydrochloride with a 14 % ammonium hydroxide solution followed by extraction. Compound 65 was synthesized via a Fischer esterification of L-tryptophan with isoamyl alcohol saturated with hydrogen chloride. The synthesis of H-methyltryptophan (44) was accomplished with the method of Snyder and Matteson.The structures of the novel compounds 55, 56, 57, 58, 59, 60, 62, 63, 69, 70, 72 and 73 were confirmed through 1H NMR, IR, EIMS, and HRMS. Elemental analyses of 62, 63, 69, 70,for 44. / Department of Chemistry
Date January 1992
CreatorsStocksdale, Mark G.
ContributorsBall State University. Dept. of Chemistry., Behforouz, Mohammad
Source SetsBall State University
Detected LanguageEnglish
Formatxii, 112 leaves : ill. ; 28 cm.
SourceVirtual Press

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