Concerning the conformations of highly substituted cyclohexanones and derivatives

Shapiro, Boris; Gattuso, Mario; Hepfinger, Norbert F.; Shone, Robert L.; White, William L.

doi:10.1016/s0040-4039(01)96402-0

Cited by 21 publications

(10 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Der Versuch, das cis-Isomere 4 in Kalium-tert-butylat-Losung zu isomerisieren, fuhrte zu dem a-Hydroxy-keton 7 . Dieses Hydroxyketon wurde bei der Cyanethylierung der cis-trans-isomeren 2,6-Dimethyl-2-aryl-cyclohexanone 3 und 4 ale Nebenprodukt isoliert [4]. -& @, 6 a-Dirnethyl-2a-(4-rnethoxy-phenyl) - …”

unclassified

Versuche zur Epimerisierung der cis‐trans‐isomeren 2,6‐Dimethyl‐2‐(4‐methoxy‐phenyl)‐cyclohexanone

Palitzsch

Huneck

Fischer

1982

Zeitschrift fuer Chemie

View full text Add to dashboard Cite

unclassified

Versuche zur Epimerisierung der cis‐trans‐isomeren 2,6‐Dimethyl‐2‐(4‐methoxy‐phenyl)‐cyclohexanone

Palitzsch

Huneck

Fischer

1982

Zeitschrift fuer Chemie

View full text Add to dashboard Cite

“…The axial positioning of the benzene ring has literature precedent, and explains the anomalous high-field chemical shift (δ H 0.42) of H 3 -18, which lies in the anisotropic shielding zone of the aromatic ring. 218,221,222 This resonance is a distinctive signature of these types of 1-aryl-1,3,3-trimethylcyclohexane moieties.…”

Section: Structure Elucidation Of Oxeatamide Amentioning

confidence: 98%

“…4. Proposed biogenesis of the aplysulphurane skeleton, adapted from Karuso et al 221 The first aplysulphurane to be isolated was aplysulphurin (222) by Karuso et al from a Dendroceratid sponge identified as Aplysilla sulphurea collected in eastern Australian waters. 221 Its structure was determined by NMR spectroscopy and confirmed by X-ray crystallography.…”

Section: The Aplysulphuranesmentioning

confidence: 99%

“…Molinski and Faulkner had previously examined D. membranosa, isolating the mildly antibacterial membranolide (236) whose aromatic ring harks back to aplysulphurin (222). 217 Subsequently, Ankisetty and co-workers report the isolation of further aromatized aplysulphuranes, the membranolides B-D (237-239) from another collection of D. membranosa.…”

Section: The Aplysulphuranesmentioning

confidence: 99%

See 1 more Smart Citation

Isolation of New Secondary Metabolites from New Zealand Marine Invertebrates

Wojnar¹

View full text Add to dashboard Cite

This study describes the isolation and structure elucidation of several known and 13 new compounds from New Zealand marine organisms. Furthermore, it describes the development of a digital mask program for the analysis of HSQC spectra of crude sponge extracts. This was used as a screening tool to identify secondary metabolite producers that warranted further analysis. As reports of metabolites from New Zealand nudibranchs are poorly represented in the literature, a study of five New Zealand nudibranch species was undertaken. These coloured and seemingly undefended nudibranchs are known to concentrate or sequester toxic metabolites from their prey, facilitating rapid isolation and structure elucidation of these metabolites. This study resulted in the isolation of a variety of metabolite classes; two new compounds, 13alpha- acetoxypukalide diol (30) and lopholide diol (31) from the nudibranch Tritonia incerta, are described. Examination of the sponge Raspailia agminata resulted in the isolation of a novel family of partially acetylated glycolipids which contain up to six glucose residues. The chromatographic separation of these compounds was a challenge due to the similarity of the congeners and their lack of a chromophore. MSguided isolation eventually led to the purification of agminosides A-E (145-149). An unidentified sponge of the order Dictyoceratida was found to contain a new isomer (186) of the known sesterterpene variabilin. As variabilin-type compounds are predominantly found from sponges of the family Irciniidae, the unidentified sponge is most likely an irciniid. In addition, the sponge contained two prenylated quinones, one of which, 189, is a new isomer of a known sponge metabolite. The sponge Darwinella oxeata contained four new nitrogenous diterpenes of the aplysulphurane (rearranged spongian) skeleton, oxeatamide A (214), isooxeatamide A (215), oxeatamide A 23-methyl ester (216) and oxeatamide B (217).

show abstract

“…Este fenômeno, explica-se quando o ciclohexano é desenhado na conformação de cadeira e leva-se em conta que o substituinte axial do carbono quaternário C-4 será afetado pelo efeito de anisotropia magnética do substituinte benzeno em axial no carbono C-10. Este deslocamento é típico das metilas axiais em C-4 em sistemas (1',3',3'-trimetilciclohexil)-benzenos (WENKERT et al, 1965;IRELAND et al, 1970;SHAPIRO et al, 1971;MOLINSKI;FAULKNER, 1987 A análise da informação espectroscópica de 52 junto com a informação do composto 48, permitiu reconhecer que tanto os deslocamentos químicos dos carbonos e hidrogênios, quanto as correlações observadas entre os prótons (espectro de COSY) e entre os prótons e carbonos (espectro de HMBC) são muito semelhantes, embora, com uma pequena diferença na substituição do nitrogênio da lactama de cinco membros.…”

unclassified

Terpenos rearranjados da esponja Darwinella cf. oxeata com potencial leishmanicida

Ramirez¹

View full text Add to dashboard Cite

The sponge Darwinella sp. was collected in Rio de Janeiro's coast and its methanolic extract showed leishmanicidal activity. The crude extract was partitioned in three fractions: hexane, AcOEt and XAD fractions. This last one was obtained by resin adsorption (mixture of XAD-2, XAD-4 and XAD-7 resins) of organic constituents from the aqueous fraction and subsequent recovery by extraction from the resins mixture. All of three fractions were also tested in leishmanicidal bioassay. The AcOEt fraction promoted 100% of parasite death. This fraction was separated into less complex fractions by size exclusion chromatography (Sephadex ® LH-20) and solid phase extractions (SPE). The compounds were isolated and purified by high-performance liquid chromatography (HPLC) combined with on-line UV detector. Seven substances were isolated, which four of them were spectroscopically identified. The membranolide, the oxeatamide A methyl ester, the oxeatamide H and the oxeatin are spongian diterpenes with nitrogenous aplysulphurane skeleton, except for the membranolide. The oxeatamides are a series of nitrogenous aplysulphurane metabolites that includes the oxeatamide A methyl ester and the oxeatamide H. All of these compounds, except the oxeatamide H, were evaluated for antiprotozoal activity against Leishmania infantum. None of these compounds displayed leishmanicidal activity.

show abstract

Concerning the conformations of highly substituted cyclohexanones and derivatives

Cited by 21 publications

References 4 publications

Versuche zur Epimerisierung der cis‐trans‐isomeren 2,6‐Dimethyl‐2‐(4‐methoxy‐phenyl)‐cyclohexanone

Versuche zur Epimerisierung der cis‐trans‐isomeren 2,6‐Dimethyl‐2‐(4‐methoxy‐phenyl)‐cyclohexanone

Isolation of New Secondary Metabolites from New Zealand Marine Invertebrates

Terpenos rearranjados da esponja <i>Darwinella</i> cf. <i>oxeata</i> com potencial leishmanicida

Contact Info

Product

Resources

About