Synthesis of 8,11-dihydroxy-pentacyclo[5.4.0.02,6.03,10.05,9]Undecane-8,11-lactam

Martins, Charles Ferreira; Viljoen, A. M.; Kruger, Hendrik G.; Joubert, Johan A.

doi:10.1016/s0040-4020(01)80226-x

Cited by 28 publications

(24 citation statements)

References 5 publications

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“…0 3,10 .0 5,9 ] undecane (trishomocubane) was first reported by Eaton et al [1]. As part of a project to synthesise pentacycloundecane derived cage amino acids [2][3][4][5], the synthesis of racemic trishomocubane hydantoin 2 [6] and the corresponding amino acid 3 was undertaken (see Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

“…Although NMR elucidation of the pentacyclo-undecane cage system is well studied 1 School of Chemistry, University of KwaZulu-Natal, Durban 4001, South Africa. 2 To whom all corespondence should be addressed; e-mail: kruger@ ukzn.ac.za [2,3,5,[13][14][15][16][17], similar studies on the intrinsically chiral [8] trishomocubane systems [6,7,[18][19][20] are somehow neglected. Various authors [16,[21][22][23] have commented on the difficulty of NMR elucidation of these cage compounds.…”

Section: Introductionmentioning

confidence: 99%

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Complete NMR Elucidation of Two N-Protected Trishomocubane Hydantoins and the Ethyl Ester of the Corresponding Amino Acid

2005

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In an attempt to resolve a racemic mixture of a trishomocubane hydantoin, the synthesis of a pair of novel diastereomers was obtained by protecting the racemic hydantoin with chlorocarbonic acid-(−)(R)-sec-butyl ester. An achiral i-propyl ester was first used to establish the procedure. The NMR elucidation of both the chiral and achiral N-protected hydantoins is described. Some proton and carbon NMR shifts on the cage are reversed when relative small changes on the protection group are introduced. The chiral centre on the protective group induced splitting of some carbon signals in the 13 C spectrum on the cage skeleton, but effective separation of the diastereomers could not be obtained. In a further attempt to demonstrate the potential use of the trishomocubane amino acid in peptide synthesis, the ethyl ester of the cage amino acid was synthesised. The structures of the amino acid derivatives were elucidated with 2D NMR techniques and the assignment of the NMR data is presented.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Complete NMR Elucidation of Two N-Protected Trishomocubane Hydantoins and the Ethyl Ester of the Corresponding Amino Acid

2005

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“…Although NMR elucidation of the pentacyclo-undecane cage system is well studied [9,[22][23][24][25][26][27][28], the elucidation of these cage systems remains very complex due to major overlap of proton signals and some carbon signals of the cage skeleton. The previous reported [9] NMR elucidation of the PCU hydantoin (5) was useful and the same numbering system was also adopted.…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

Regioselective protection of hydantoins – essential for hydantoin based anti-epileptic drugs

Kruger

Mdluli

2006

Struct Chem

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The synthesis and NMR elucidation of six novel mono-and bis-Boc protected hydantoins are reported. The hydantoins 5-methylhydantoin, 5,5-dimethylhydantoin and a pentacycloundecane hydantoin exhibit an increase in substitution and steric hindrance at C-5. Kinetic and reagent controlled monoprotection of the smaller hydantoins achieve regioselective protection at N-1 while the bulky cage hydantoin is protected at N-3 . Hydantoin based anti-epileptic drugs such as 5,5-diphenylhydantoin require regioselective substitution at N-3 for enhanced pharmaceutical activity. The study enhances our understanding of the activity of the nitrogen atoms on hydantoin rings.

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“…As part of an ongoing programme to utilize NMR spectroscopy for the structure elucidation of pentacyclo-undecane (PCU) derivatives, the NMR assignments of eight PCU diamine derivatives (1)(2)(3)(4)(5)(6)(7)(8) was attempted (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

“…[1,[5][6][7][8][9][10][11] Geminal/vicinal proton-proton coupling and long-range proton-proton interactions result in broad unresolved resonances. However, the emergence of a range of standard 2D NMR techniques has helped a great deal in overcoming these problems.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and NMR elucidation of novel pentacyclo-undecane diamine ligands

et al. 2009

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The synthesis and NMR elucidation of eight novel pentacyclo-undecane (PCU) diamine compounds are reported. These ligands are potential anti-inflammatory agents to be used against rheumatoid arthritis (RA). Onedimensional NMR techniques ( 1 H and 13 C spectra) show major overlapping of methine resonances of the ''cage'' (PCU) thereby making it extremely difficult to assign all NMR signals. This overlapping occurs as a result of the substitutions made at the quaternary carbons (C-8/C-11) of the cage. Two-dimensional NMR techniques proved to be a useful tool in overcoming this problem.

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Synthesis of 8,11-dihydroxy-pentacyclo[5.4.0.02,6.03,10.05,9]Undecane-8,11-lactam

Cited by 28 publications

References 5 publications

Complete NMR Elucidation of Two N-Protected Trishomocubane Hydantoins and the Ethyl Ester of the Corresponding Amino Acid

Complete NMR Elucidation of Two N-Protected Trishomocubane Hydantoins and the Ethyl Ester of the Corresponding Amino Acid

Regioselective protection of hydantoins – essential for hydantoin based anti-epileptic drugs

Synthesis and NMR elucidation of novel pentacyclo-undecane diamine ligands

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