Synthesis of δ-lactams from pentacyclo[5.4.0.02,6.03,10.05,9]Undecane-8,11-dione

Martins, F. J. C.; Viljoen, A. M.; Kruger, Hendrik G.; Joubert, Johan A.; Wessels, Philippus L.

doi:10.1016/s0040-4020(01)89270-x

Cited by 27 publications

(19 citation statements)

References 5 publications

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“…Furthermore, the binding of the synthetic ["'I]Tyr LTX I to its receptor was completely lost after modification of Arg-6 and Arg-13 [16]. Arg-6 and Arg-7 of PO, might well be also located in a part of the molecule proposed to be an a-helix in LTX I (from Arg-6 to Gly-16) [17]. The substitution of the Arg-7 of PO, by Met in LTX I could explain the Highly conserved amino acid residues (Fig.…”

Section: Resultsmentioning

confidence: 99%

Characterization of a new leiurotoxin I‐like scorpion toxin

et al. 1993

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Three novel peptide inhibitors of the SK,,< channels were purdied to homogeneity from the venom of the scorpion Androctonus ntauretanicus muuretunzcus using one step of RP-HPLC and competrtton assays with ["SI]apamin to rat brain synaptosomes PO,, PO? and PO, have K,, of 100, 100 and 0.02 nM, respectively, for the apamm binding site. The sequence of PO3 was established and compared to that of other scorpion toxins active on K' channels: it contains 31 residues and has a free carboxyl end. It shares sequence srmilarny wnh apamin and leiurotoxm 1.

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Section: Resultsmentioning

confidence: 99%

Characterization of a new leiurotoxin I‐like scorpion toxin

et al. 1993

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“…Pentacyclo[6.3.0.0 2,6 .0 3,10 .0 5,9 ]undecane (trishomocubane) was first reported by Eaton et al in 1968, as a keto derivative. 1 Later, Underwood and Ramamoorthy were successful in synthesizing the underivatized C 11 H 14 polycyclic hydrocarbon, for which they proposed the trivial name trishomocubane (1) (Fig.…”

Section: Introductionmentioning

confidence: 99%

Complete NMR elucidation of a novel trishomocubane hydantoin and its mono‐ and bis‐t‐Boc protected derivatives

Fourie¹,

Govender²,

Hariprakasha³

et al. 2004

Magnetic Reson in Chemistry

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The syntheses of a novel trishomocubane hydantoin and its mono- and bis-protected t-Boc derivatives are described. The less nucleophilic N-3' nitrogen of the hydantoin ring is protected first when treated with di-tert-butyl dicarbonate (t-Boc anhydride), possibly owing to steric hindrance by the bulky trishomocubane cage skeleton. More basic conditions were required to form the bis-protected t-Boc hydantoin with the same reagent. The structures of these novel compounds were elucidated with 2D NMR techniques. The proton spectrum of the trishomocubane skeleton is complex owing to major overlap of proton signals. A high-level DFT calculation was used to determine some of the crucial interatomic positions, which assisted with the elucidation of the structures. The assignment of proton and carbon signals of the three structures is described and it differs significantly from each other and also from the trishomocubanol precursor. The bis-Boc hydantoin is required for a more facile hydrolysis to the corresponding trishomocubane amino acid at room temperature.

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“…In the case of the monoacetate 6 acetylation could occur at three different sites. However, an NMR investigation clearly revealed that treatment of 2 with acetic anhydride at room temperature produced a compound (6) and the methine carbon atoms resonating at υ C D 42.80 (C-1) and 50.76 (C-10). These observations unambiguously prove that acetylation occurred on the amino group of 2 and that the CH 3 -CO-NH-group is coupled to C-11.…”

Section: Resultsmentioning

confidence: 99%

“…We recently reported 6 that treatment of pentacyclo [5.4.0.0 2,6 .0 3,10 .0 5,9 ]undecane-8,11-dione (1) with an aqueous mixture of sodium cyanide, ammonium chloride and ammonia unexpectedly led to 11-amino-8-hydroxypentacyclo [5.4.0.0 2,6 .0 3,10 .0 5,9 ]undecane-8,11-lactam (2). Suitable crystals for x-ray crystallographic analysis could not be obtained, which left little choice of method for structural studies.…”

Section: Introductionmentioning

confidence: 99%

Structure elucidation of 11‐amino‐8‐hydroxypentacyclo[5.4.0.0^{2, 6}.0^{3, 10}.0^{5, 9}]undecane‐8,11‐lactam through selective acetylation and complete ¹H and ¹³C NMR spectral assignment of the mono‐, di‐ and triacetates

Martins

Viljoen

Kruger

et al. 2004

Magnetic Reson in Chemistry

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NMR techniques cannot unambiguously distinguish between 11-amino-8-hydroxypentacyclo[5.4.0.0(2, 6).0(3, 10).0(5, 9)]undecane-8,11-lactam and 8-amino-11-hydroxypentacyclo[5.4.0.0(2, 6).0(3, 10).0(5, 9)]undecane-8,11-lactam, both of which are possible products during the reaction of pentacyclo[5.4.0.0(2, 6).0(3, 10).0(5, 9)]undecane-8,11-dione with Strecker reagents. Treatment of 11-amino-8-hydroxy-pentacyclo[5.4.0.0(2, 6).0(3, 10).0(5, 9)]undecane-8,11-lactam with acetic anhydride at room temperature produced a monoacetate. With acetic anhydride containing sodium acetate, a triacetate was obtained at reflux temperature. Treatment with acetyl chloride and N,N-dimethylaniline produced a diacetate. High-field 1H and 13C NMR techniques were used in the structure elucidation and assignment of the different NMR resonances of these three acetylated compounds.

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Synthesis of δ-lactams from pentacyclo[5.4.0.02,6.03,10.05,9]Undecane-8,11-dione

Cited by 27 publications

References 5 publications

Characterization of a new leiurotoxin I‐like scorpion toxin

Characterization of a new leiurotoxin I‐like scorpion toxin

Complete NMR elucidation of a novel trishomocubane hydantoin and its mono‐ and bis‐t‐Boc protected derivatives

Structure elucidation of 11‐amino‐8‐hydroxypentacyclo[5.4.0.0^{2, 6}.0^{3, 10}.0^{5, 9}]undecane‐8,11‐lactam through selective acetylation and complete ¹H and ¹³C NMR spectral assignment of the mono‐, di‐ and triacetates

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Synthesis of δ-lactams from pentacyclo[5.4.0.02,6.03,10.05,9]Undecane-8,11-dione

Cited by 27 publications

References 5 publications

Characterization of a new leiurotoxin I‐like scorpion toxin

Characterization of a new leiurotoxin I‐like scorpion toxin

Complete NMR elucidation of a novel trishomocubane hydantoin and its mono‐ and bis‐t‐Boc protected derivatives

Structure elucidation of 11‐amino‐8‐hydroxypentacyclo[5.4.0.02, 6.03, 10.05, 9]undecane‐8,11‐lactam through selective acetylation and complete 1H and 13C NMR spectral assignment of the mono‐, di‐ and triacetates

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Structure elucidation of 11‐amino‐8‐hydroxypentacyclo[5.4.0.0^{2, 6}.0^{3, 10}.0^{5, 9}]undecane‐8,11‐lactam through selective acetylation and complete ¹H and ¹³C NMR spectral assignment of the mono‐, di‐ and triacetates