Mearsine, a unique isoquinuclidine alkaloid: x-ray crystal structure of mearsine picrate

Robertson, G. B.; Tooptakong, U.; Lamberton, J. A.; Geewananda, Y. A.; Gunawardana, P.; Ralph, I.; Bick, C

doi:10.1016/s0040-4039(01)81265-x

Cited by 17 publications

(7 citation statements)

References 3 publications

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“…Thus (Fig. Further, a significant number of cases were located in which the ortho substituent was itself a strong hydrogen-bond acceptor and one such example (Robertson, Tooptakong, Lamberton & Geewanda, 1984) is depicted in Fig. The N---O 1 vector is at tp = 0 ° with O 1 at the origin.…”

Section: Monf Formation Monf Geometry and Directionality Of H Approamentioning

confidence: 99%

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Hydrogen-Bond Acceptor Properties of Nitro-O Atoms: A Combined Crystallographic Database and Ab Initio Molecular Orbital Study

Allen¹,

Baalham²,

Lommerse³

et al. 1997

Acta Crystallogr B Struct Sci

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Crystallographic data for 620 C--nitro-O...H--N,O hydrogen bonds, involving 560 unique H atoms, have been investigated to the van der Waals limit of 2.62 A. The overall mean nitro-O...H bond length is 2.30 (1) A, which is much longer (weaker) than comparable hydrogen bonds involving >C~O acceptors in ketones, carboxylic acids and amides. The donor hydrogen prefers to approach the nitro-O atoms in the C--NO2 plane and there is an approximate 3:2 preference for hydrogen approach between the two nitro-O atoms, rather than between the C and O substituents. However, hydrogen approach between the two O acceptors is usually strongly asymmetric, the H atom being more closely associated with one of the O atoms: only 60 H atoms have both O...H distances < 2.62 A. The approach of hydrogen along putative O-atom lone-pair directions is clearly observed. Ab-initio-based molecular orbital calculations (6-31G** basis set level), using intermolecular perturbation theory (IMPT) applied to the nitromethane-methanol model dimer, agree with the experimental observations. IMPT calculations yield an attractive hydrogen-bond energy of ca -15 kJ mol-1, about half as strong as the >C=O...H bonds noted above.

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Section: Monf Formation Monf Geometry and Directionality Of H Approamentioning

confidence: 99%

“…Steric and (here) electrostatic factors affect the geometry of mono-coordinate motif 0ID hydrogen bonding to nitro-O atoms (example from CSD reference code CIJXOI:Robertson, Tooptakong, Lamberton & Geewanda, 1984). (a) The nitro--O...H distances are consistently shorter in motifs (I) and (II).…”

mentioning

confidence: 99%

Hydrogen-Bond Acceptor Properties of Nitro-O Atoms: A Combined Crystallographic Database and Ab Initio Molecular Orbital Study

Allen¹,

Baalham²,

Lommerse³

et al. 1997

Acta Crystallogr B Struct Sci

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show abstract

“…The Chinese plant Lobeliu duvidii contains a new alkaloid lelobanonoline (24), formulated on spectral evidence.,, A synthesis of the two unnatural isomers, ( 25) and ( 26), of the alkaloid tecomanine (the isotecomanines) has been described, via a hydroboration-oxidation route, under stereochemical…”

Section: Piperidine Alkaloidsmentioning

confidence: 99%

Pyrrole, pyrrolidine, piperidine, pyridine, and azepine alkaloids

Pinder

1992

Nat. Prod. Rep.

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“…Although many indolizidine alkaloids have been isolated, isoquinuclidinone alkaloids are very rare indeed. In fact, mearsine 8 , , isolated from another member of the Elaeocarpaceae family, Peripentadenia mearsii , appears to be the only other published example. We recently reported a facile route to a range of isoquinuclidinones from 6-acyl-cyclohex-2-enones, employing aqueous ammonia in a one-pot tandem amination/imination procedure, and applied this methodology as part of an efficient synthesis of (−)-mearsine 8 .…”

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confidence: 99%

The Preparation of (−)-Grandisine B from (+)-Grandisine D; A Biomimetic Total Synthesis or Formation of an Isolation Artefact?

2011

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An efficient new alkyne-acetal cyclization procedure has been developed to prepare enantiopure indolizidine building blocks from l-proline and then applied to prepare the Elaeocarpus-derived alkaloids grandisine B and grandisine D in an efficient manner. However, evidence is presented which indicates that grandisine B does not occur naturally but is formed by reaction of grandisine D with ammonia during the extraction/purification process.

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Mearsine, a unique isoquinuclidine alkaloid: x-ray crystal structure of mearsine picrate

Cited by 17 publications

References 3 publications

Hydrogen-Bond Acceptor Properties of Nitro-O Atoms: A Combined Crystallographic Database and Ab Initio Molecular Orbital Study

Hydrogen-Bond Acceptor Properties of Nitro-O Atoms: A Combined Crystallographic Database and Ab Initio Molecular Orbital Study

Pyrrole, pyrrolidine, piperidine, pyridine, and azepine alkaloids

The Preparation of (−)-Grandisine B from (+)-Grandisine D; A Biomimetic Total Synthesis or Formation of an Isolation Artefact?

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