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Total synthesis of lavendamycin analogs

The synthesis of 7-N -furoyllavendamycin methyl ester (35), 7-N -furoyl demethyllavendamycin methyl ester (36), 7-N -furoyldemethyllavendamycin ethyl ester (37), 7-N -furoyldemethyllavendamycin propyl ester (38), 7-N -furoyl demethyl lavendamycin butyl ester (39), 7-N -furoyldemethyllavendamycin isoamyl ester (40),7-N -furoyldemethyllavendamycin cyclohexyl ester (41), 7-N -furoyldemethyl lavendamycin octyl ester (42), 7-N -furoyldecarboxydemethyllavendamycin (43), and demethyl lavendamycin isoamyl ester (44) are described. Pictet-Spengler condensation of 7-furoylamino-2-formylquinoline-5, 8-dione (55) with (3-methyltryptophan methyl ester (4), Ltryptophan methyl ester (56), L-tryptophan ethyl ester (57), L-tryptophan propyl ester (58), L-tryptophan butyl ester (59), L-tryptophan isoamyl ester (60), L-tryptophan cyclohexyl ester (61), L-tryptophan octyl ester (62), L-tryptamine (63), in xylene, or anisole afforded ten lavendamycin analogs.Aldehyde 55 was prepared according to the following general procedure.Nitration of 8-hydroxy-2-methylquinoline (30) gave 8-hydroxy-2-methyl-5,7dinitroquinoline (31). Compound 31 was then hydrogenated and acylated with 2-furoyl chloride (or acetic anhydride ) to yield 5,7-difuroylamino-8-hydroxy-2-methylquinoline (53) or 5,7-diacetamino-8-acetoxy-2-methyl- quinoline (33). Compounds 53 and 33 were oxidized by potassium dichromate to give the corresponding 5,8-diones 54, and 27. Treatment of 53, and 27 with selenium dioxide in refluxing wet dioxane afforded compounds 55 and 28.Compound 4 was previously prepared by other members of our group, compounds 56, 57, 59, and 62 were obtained through the neutralization of the corresponding Ltryptophan ester hydrochlorides with a 14% ammonium hydroxide solution followed by extraction. Compounds 58, 60, 61 were synthesized via a Fischer esterification of Ltryptophan with : propyl alcohol, isoamyl alcohol, and cyclohexyl alcohol saturated with hydrogen chloride.The structures of compounds 53, 54, 55, 35, 36, 37, 38, 39, 40, 41, 42, 43, and 44 were confirmed through 1H NMR, IR, EIMS, and HRMS. Elemental analyses of 53, 54, and 55 are also included.The structures of esters 56, 57, 58, 59, 60, 61, 62, and 63 were confirmed by 1H NMR. / Department of Chemistry

Identiferoai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/185241
Date January 1995
CreatorsOlang, Fatemeh
ContributorsBall State University. Dept. of Chemistry., Behforouz, Mohammad
Source SetsBall State University
Detected LanguageEnglish
Formatxii, 94 leaves : ill. ; 28 cm.
SourceVirtual Press

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