(+)-9-Aza-1-methylbicyclo[3,3 ,1]nonan-3-one, a new alkaloid from Euphorbia atoto Forst

Hart, NK; Johns, SR; Lamberton, JA

doi:10.1071/ch9670561

Cited by 41 publications

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“…All the synthesized compounds were characterized by elemental analysis, IR, 1 H NMR, 13 Tables 1 and 3, respectively. The 2D 1 H and 13 C correlations of compound 12 are shown in Tables 2 and 4.…”

Section: Resultsmentioning

confidence: 99%

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¹H and ¹³C NMR spectral assignments of some novel 2,4,6,8‐tetraaryl‐3,7‐diazabicyclo[3.3.1]nonan‐9‐one derivatives

Parthiban

Ramachandran

Aridoss

et al. 2008

Magnetic Reson in Chemistry

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The (1)H and (13)C NMR spectra of 2,4,6,8-tetraaryl-3,7-diazabicyclo[3.3.1]nonan-9-ones (1-2), oximes (3-8) and O-benzyl oximes (9-12) were recorded. The chemical shifts were unambiguously assigned using 1D and 2D NMR spectral data. The results clearly indicate that the compounds exist in chair-boat conformation with equatorial and axial orientation of the aryl groups in the chair and boat forms, respectively. Since the molecules are flexible and dynamic in solution, the chair and boat forms are mutually interconvertible. In 3-12, because of the effect of oximation/oximination, all the protons in the heterobicyclic systems gave distinct signals except the benzylic protons of the boat form. In all synthesized compounds, the aryl group protons at C-6,8 are shielded by the aryl groups at C-2,4 and therefore appear in the lower frequency region than the aryl groups at C-2,4.

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Section: Resultsmentioning

confidence: 99%

“…All other carbon signals of the synthesized oximes/oxime ethers (except compound 8, 13 C NMR for this compound could not be recorded owing to poor solubility) are assigned by comparison with those of compound 12 and summarized in Table 3. The observed HSQC and HMBC correlations of 12 are listed in Table 4.…”

Section: Carbon Chemical Shiftsmentioning

confidence: 99%

¹H and ¹³C NMR spectral assignments of some novel 2,4,6,8‐tetraaryl‐3,7‐diazabicyclo[3.3.1]nonan‐9‐one derivatives

Parthiban

Ramachandran

Aridoss

et al. 2008

Magnetic Reson in Chemistry

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“…The specific rotation [α] D of +5.7 was also compatible with that found in the literature {lit. [α] D +6 (c 2.0, MeOH),[19]}. Finally, the synthetic sample obtained by the authors when treated with (S)-Mosher's acid chloride was converted entirely to a Mosher amide, confirming to be a sample with a high level of enantiomeric purity.…”

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confidence: 79%

“…A methyl analog, (+)-euphococcinine (2), has been found in vegetable and animal kingdoms. The compound was first isolated from the Australian coastal plant Euphorbia atoto [19], and it is also present in the defense secretion of ladybirds Cryptolaemus montrouzieri [18] and Epilachna varivestis [16]. Also, (+)-N-methyleuphococcinine (3) has been identified as a trace homotropane alkaloid isolated from the spruce tree Picea pungens [20] (Figure 2).…”

Section: Introductionmentioning

confidence: 99%

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

Lima¹,

Santana²,

Birkett³

et al. 2021

Beilstein J. Org. Chem.

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The 9-azabicyclo[3.3.1]nonane ring system is present in several insect- and plant-derived alkaloids. (−)-Adaline (1) and (+)-euphococcinine (2), found in secretions of Coccinelid beetles, and (+)-N-methyleuphococcinine (3), isolated from the Colorado blue spruce Picea pungens, are members of this alkaloid family. Their unique bicyclic system with a quaternary stereocenter, and the potent biological activity exerted by these homotropane alkaloids, make them attractive synthetic targets. This work aims briefly to review the chemical ecology of Adalia bipunctata and the recent methodologies to obtain adaline (1), euphococcinine (2), and N-methyleuphococcinine (3).

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“…The concept is highlighted via a synthesis of the azabicyclo[3.3.1]nonane natural product, (-)-adaline 6. Adaline possesses the 9-azabicyclo[3.3.1]nonane skeleton common to several insect- and plant-derived alkaloids, including pseudopelletierine,7 (+)-euphococcinine,8 and porantherine 9. This structure is a higher homolog of the medicinally-important tropane skeleton.…”

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confidence: 99%

Organometallic Enantiomeric Scaffolding. Sequential Semipinacol/1,5-“Michael-like” Reactions as a Strategic Approach to Bridgehead-Quaternary Center Aza[3.3.1]Bicyclics: Application to the Total Synthesis of (−)-Adaline

et al. 2009

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TpMo(CO) 2 (5-oxo-η 3 -pyranyl) and TpMo(CO) 2 (5-oxo-η 3 -pyridinyl) complexes 1 and 2 (Scheme 1, Tp = hydridotrispyrazolylborate) and their progeny have been developed as organometallic enantiomeric scaffolds for the asymmetric construction of a wide variety of heterocyclic systems. 1 Readily available and easily synthesized, 2 single enantiomers of these simple air-stable organometallic π-complexes function as scaffolds from which widely differing families of complex organic structures can be elaborated in an enantiospecific fashion. The organometallic nature of these enantiomeric scaffolds provides opportunities to implement conceptually unique synthetic design strategies. Herein is described one such strategy: a new molybdenum-mediated semipinacol rearrangement delivering α-quaternary pyranyl and pyridinyl systems that, when coupled sequentially with a molybdenum-mediated intramolecular 1,5-"Michael-like" reaction of 5-oxopyridinyl molybdenum complexes, 1m can provide a novel enantiocontrolled entry to heteroatom-bridged [3.3.1]bicyclic systems bearing quaternary centers 3,4,5 adjacent to the ring heteroatom (Scheme 1). The concept is highlighted via a synthesis of the azabicyclo[3.3.1]nonane natural product, (-)-adaline. 6 Adaline possesses the 9-azabicyclo[3.3.1]nonane skeleton common to several insect-and plant-derived alkaloids, including pseudopelletierine, 7 (+)-euphococcinine, 8 and porantherine. 9 This structure is a higher homolog of the medicinally-important tropane skeleton. A number of racemic 10 and enantiospecific syntheses 11 of adaline have been reported. The molybdenum scaffold-based synthesis of heteroatom-bridged [3.3.1]bicyclics bearing ring junction quaternary centers suggested in Scheme 1 first requires the stereocontrolled construction of α-quaternary 5-oxopyranyl and 5-oxopyridinyl molybdenum complexes. This was accomplished through the agency of the molybdenum-mediated semipinacol reaction shown in Table 1. The requisite semipinacol precursors 5-12 were prepared from 5-oxopyranyl scaffold 1 and 5-oxopyridinyl scaffold 2 (both readily available in racemic and high enantiopurity forms on multigram scale in 2-3 isolation steps from furfuryl alcohol and furfuryl amine, respectively 2 ) by conversion of 1 and 2 into the corresponding 6-alkylidene-5-oxo complexes 3 and 4 via a Mukaiyama aldol-dehydration reaction sequence. 12 Specific data points for both the pyranyl and pyridinyl series scaffolds are provided in Table 1 Selective 1,2-addition of Grignard reagents to the enones 3 and 4 took place anti to the TpMo (CO) 2 moiety in good to excellent yields, except with the more hindered i-Pr and t-Bu reagents. Treatment of adducts 5-12 with HCl in dioxane induced a rapid and stereospecific semipinacol reaction for those R 2 substituents with good migratory aptitudes such as allyl, phenyl, vinyl, and t-Bu, but not for R 2 = Me or i-Pr. The geometry of the alkylidene residue influenced the outcome of the semipinacol reaction for the pyridinyl series scaffolds, but not for the pyranyl scaffold...

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(+)-9-Aza-1-methylbicyclo[3,3 ,1]nonan-3-one, a new alkaloid from Euphorbia atoto Forst

Abstract: A new alkaloid isolated from Euphorbia atoto Forst. has been shown to be (+)-9-aza-1 -methylbicyclo[3,3,1]nonan-3-one.

Cited by 41 publications

References 0 publications

¹H and ¹³C NMR spectral assignments of some novel 2,4,6,8‐tetraaryl‐3,7‐diazabicyclo[3.3.1]nonan‐9‐one derivatives

¹H and ¹³C NMR spectral assignments of some novel 2,4,6,8‐tetraaryl‐3,7‐diazabicyclo[3.3.1]nonan‐9‐one derivatives

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

Organometallic Enantiomeric Scaffolding. Sequential Semipinacol/1,5-“Michael-like” Reactions as a Strategic Approach to Bridgehead-Quaternary Center Aza[3.3.1]Bicyclics: Application to the Total Synthesis of (−)-Adaline

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(+)-9-Aza-1-methylbicyclo[3,3 ,1]nonan-3-one, a new alkaloid from Euphorbia atoto Forst

Abstract: A new alkaloid isolated from Euphorbia atoto Forst. has been shown to be (+)-9-aza-1 -methylbicyclo[3,3,1]nonan-3-one.

Cited by 41 publications

References 0 publications

1H and 13C NMR spectral assignments of some novel 2,4,6,8‐tetraaryl‐3,7‐diazabicyclo[3.3.1]nonan‐9‐one derivatives

1H and 13C NMR spectral assignments of some novel 2,4,6,8‐tetraaryl‐3,7‐diazabicyclo[3.3.1]nonan‐9‐one derivatives

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

Organometallic Enantiomeric Scaffolding. Sequential Semipinacol/1,5-“Michael-like” Reactions as a Strategic Approach to Bridgehead-Quaternary Center Aza[3.3.1]Bicyclics: Application to the Total Synthesis of (−)-Adaline

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¹H and ¹³C NMR spectral assignments of some novel 2,4,6,8‐tetraaryl‐3,7‐diazabicyclo[3.3.1]nonan‐9‐one derivatives

¹H and ¹³C NMR spectral assignments of some novel 2,4,6,8‐tetraaryl‐3,7‐diazabicyclo[3.3.1]nonan‐9‐one derivatives