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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

Cromenos de origem policetídica em Peperomia villipetiola / Chromenes of polyketide origin in Peperomia villipetiola

Malquichagua Salazar, Karina Josefina 15 August 2003 (has links)
Estudo fitoquímico dos extratos de folhas e galhos de Peperomia villipefiola (\"hierba de la plata\"), coletada no Peru, resultou no isolamento e caracterização da miristicina (3-metoxi-4,5-metilenedioxi-alil-benzene) e sete novos cromenos. Os cromenos tiveram suas estruturas elucidadas através de análises espectroscópicas como sendo: 5-hidroxi-7-metil-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL1), 7-metil-5-metoxi-2,2-dimetil-2H-1-cromeno-8-carboxilato de metila (PVL2), 7-hydroxy-5-metil-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL3), 5-metil-7-metoxi-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL4), ácido 7-hidroxi-5-metanol-2,2-dimetil-2H-1-cromeno-6-carboxílico (PVL5), ácido 5-metanol-7-metoxi-2,2-dimetil-2H-1-cromeno-6-carboxílico (PVL6) e 5-acetoximetanol-7-hidroxi-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL7). Uma proposta biossintética foi sugerida, no qual o anel aromático seria formado pela via policetídica enquanto que a porção isoprênica poderia ser oriunda tanto da via do mevalonato quanto da via do fosfato de metileritriol. / The leaves and stems extracts from the Peperomia villipetiola (\"herb of the silver\"), collected in Peru, yielded myristicine (3-methoxy-4,5-methy/enedioxy-allylbenzene) and seven new chromenes. The chromenes, all new compounds, had their structures elucidated by means of spectroscopic analysis as: methyl 5-hydroxy-7-methyl-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL1), methyl 5-methoxy-7-methyl-2,2-dimethyl-2H-1-chromene-8-carboxylate (PVL2), methyl 7-hydroxy-5-methyl-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL3), methyl 7-methoxy-5-methyl-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL4), 5-methanol7-hydroxy-2 ,2-dimethyl-2H-1-chromene-6-carboxylic acid (PVL5), 5-methanol-7-methoxy-2,2-dimethyl-2H-1-chromene-6-carboxylic acid (PVL6), and methyl 5-acetoxymethanol-7-hydroxy-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL7). A biosynthetic scheme was suggested in which the aromatic ring should be formed by polyketide pathway while the isoprenyl moiety either from mevalonic acid or methylerythriol phosphate pathway.
2

Cromenos de origem policetídica em Peperomia villipetiola / Chromenes of polyketide origin in Peperomia villipetiola

Karina Josefina Malquichagua Salazar 15 August 2003 (has links)
Estudo fitoquímico dos extratos de folhas e galhos de Peperomia villipefiola (\"hierba de la plata\"), coletada no Peru, resultou no isolamento e caracterização da miristicina (3-metoxi-4,5-metilenedioxi-alil-benzene) e sete novos cromenos. Os cromenos tiveram suas estruturas elucidadas através de análises espectroscópicas como sendo: 5-hidroxi-7-metil-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL1), 7-metil-5-metoxi-2,2-dimetil-2H-1-cromeno-8-carboxilato de metila (PVL2), 7-hydroxy-5-metil-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL3), 5-metil-7-metoxi-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL4), ácido 7-hidroxi-5-metanol-2,2-dimetil-2H-1-cromeno-6-carboxílico (PVL5), ácido 5-metanol-7-metoxi-2,2-dimetil-2H-1-cromeno-6-carboxílico (PVL6) e 5-acetoximetanol-7-hidroxi-2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (PVL7). Uma proposta biossintética foi sugerida, no qual o anel aromático seria formado pela via policetídica enquanto que a porção isoprênica poderia ser oriunda tanto da via do mevalonato quanto da via do fosfato de metileritriol. / The leaves and stems extracts from the Peperomia villipetiola (\"herb of the silver\"), collected in Peru, yielded myristicine (3-methoxy-4,5-methy/enedioxy-allylbenzene) and seven new chromenes. The chromenes, all new compounds, had their structures elucidated by means of spectroscopic analysis as: methyl 5-hydroxy-7-methyl-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL1), methyl 5-methoxy-7-methyl-2,2-dimethyl-2H-1-chromene-8-carboxylate (PVL2), methyl 7-hydroxy-5-methyl-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL3), methyl 7-methoxy-5-methyl-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL4), 5-methanol7-hydroxy-2 ,2-dimethyl-2H-1-chromene-6-carboxylic acid (PVL5), 5-methanol-7-methoxy-2,2-dimethyl-2H-1-chromene-6-carboxylic acid (PVL6), and methyl 5-acetoxymethanol-7-hydroxy-2,2-dimethyl-2H-1-chromene-6-carboxylate (PVL7). A biosynthetic scheme was suggested in which the aromatic ring should be formed by polyketide pathway while the isoprenyl moiety either from mevalonic acid or methylerythriol phosphate pathway.

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