The constitution and stereochemistry of obtusafuran

Gregson, Matthew; Ollis, W. D.; Redman, B. T.; Sutherland, I. O.; Dietrichs, H. H.

doi:10.1039/c19680001394

Cited by 15 publications

(18 citation statements)

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“…As porosinas apresentam os grupos arílico e metílico em cis e a metila absorve em ca. 0,5 d no espectro de RMN de 1 H. As canelinas e as armeninas possuem grupos arílico e metílico em trans e as metilas absorvem em RMN de 1 H entre 1,0 a 1,2 d. A relação cis dos grupos metílico e alílico nas canelinas e a relação destes grupos em trans nas armeninas mostram diferenças na absorção da metila no espectro de RMN de 13 C devido ao efeito g de proteção diamagnética. Assim, na relação cis, C9 da canelina absorve em 11,7 d e na relação trans da armenina C9 absorve em 17,5 d nos respectivos de espectros de RMN de 13 C.…”

Section: Figura 2 Estruturas De Modelos Dos Cromóforos Da Porosinaunclassified

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Aspectos estruturais de algumas neolignanas hidrobenzofurânicas

Yoshida¹

2012

Quím. Nova

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. Gov. Danilo de Matos Areosa, 690, Brasil Recebido em 3/5/12; aceito em 2/7/12; publicado na web em 5/10/12 STRUCTURAL ASPECTS OF SOME HYDROBENZOFURAN NEOLIGNANS. The neolignans are defined as dimers of allylphenol and propenylphenol between itself or crossed, whose bond does not occur by the 8-8' carbons like lignans. This review centered on stereochemical aspects of the hydrobenzofuran type, a widespread skeleton among neolignans. The chemical structures established based on spectrometric data are registered in the literature. The absolute configurations reported previously were determined by chiroptical techniques. Some chemical transformations with neolignans, performed in previous studies, afforded products which are accumulated in other vegetal species and contributed to assign the unknown stereochemistry of these natural compounds. Possible biosynthetic pathways are also proposed.

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Section: Figura 2 Estruturas De Modelos Dos Cromóforos Da Porosinaunclassified

“…13 A melanoxina e o obtusafurano (Figura 8) serviram de modelos para a configuração absoluta de neolignanas.…”

Section: Determinação Da Configuração Absolutaunclassified

Aspectos estruturais de algumas neolignanas hidrobenzofurânicas

Yoshida¹

2012

Quím. Nova

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“…It is known that the methyl signal in a cis-2-aryl-3-methyl-2,3-dihydrobenzofuran shifts to higher field (more than 0.6 ppm) compared with that of the trans-isomer. 5) However no such a shift was observed with the C-9 methylene signal (b 4.25) oflappaol B diacetate likewise with that of dehydrodiconiferyl triacetate (b 4.35), which has trans-configuration, and the stereostructure of lappaol B was confirmed as 1.…”

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confidence: 98%

Enzymatic Synthesis of Lappaol B

Ichihara

Kawagishi

Sasagawa

et al. 1981

Agricultural and Biological Chemistry

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“…After the mixture had been filtered and concentrated, the residue was recrystallized from EtOAc-n-hexane, yielding dihydropiperenone (II) 6.37 (lH, brs, H on C-4), 6.8 ~ 6.9 (3H, overlap, aromatic protons).…”

Section: Catalytic Hydrogenation Of Piperenone (I)mentioning

confidence: 99%

“…'~13 cm-1 ; no hydroxy absorption, 1687 (conjugated ketone), 1642 and 920 (terminal vinyl), 1607, 1596 and 1515 (phenyl), UV A!~~H nm (e); 232 (16,600), 280 (3640), 285 (3240, shoulder). The NMR spectrum of I in deuteriochloroform exhibited two doublets at 0 0.98 (3H, J 7Hz) and 4.12 (lH, J-llHz) and a double quartet at 0 2.90 (1 H, J = 11, 7Hz), the typical AMX 3 -type signal of a CH~ yH-yH-(O)-unit; a pair of doublets at 13 2.63 and 3.29 (each IH, J 17Hz) and two sharp singlets at () 3.40 (3H) and 3.53 (3H) indicating the presence of an isolated methylene and two aliphatic methoxy groups; and two sharp singlets at () 3.85 (3H) and 3.87 (3H) and an overlapped signal at () 6.8 ~ 6.9 (3H) which appeared as a well-defined ABC-type signal (OA 6.57, (}B 6.76 and (}c 6.93; J AB -8Hz and J BC = 1. 5Hz) in d 6 -benzene showed the presence of a dimethoxyphenyl function.…”

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confidence: 99%