Synthesis of Analogues of GABA. XIV. Synthesis and Activity of Unsaturated Derivatives of 5-Aminopentanoic Acid (d-Aminovaleric Acid)

Allan, RD; Dickenson, Helena W.; Johnston, G. A. R.; Kazlauskas, Rymantas; Tran, H. W.

doi:10.1071/ch9851651

Cited by 25 publications

(6 citation statements)

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“…The thioesters 9 , 10 and 12 , based on the same δ‐amino acid 6 (corresponding to subunit A ), were selected as linear precursors to macrocycles 1 – 3 (Scheme ). Thus, trans ‐β‐hydromuconic acid 5 was transformed into the unsaturated δ‐amino‐acid 6 (49 %) and then into its corresponding Boc‐protected amine 7 (97 %) 50 . n‐ Butanethiol was coupled with 7 by means of EDCI, DMAP and HOBt at −17 °C to yield the thioester 8 (86 %).…”

Section: Resultsmentioning

confidence: 99%

Efficient Synthesis and Astonishing Supramolecular Architectures of Several Symmetric Macrolactams

Baillargeon

Bernard

Gauthier

et al. 2007

Chemistry A European J

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The synthesis of four C(n) symmetric macrocyclic lactams cyclo-[NH-CH(2)-CH=CH-CH(2)-CO](n) (1, n=2; 2, n=3; 3, n=4) and cyclo-[NH-CH(2)-CH(2)-CH=CH-CO](3) (4) has been achieved by two approaches. A linear route leads to precursors that are subsequently macrocyclized in a separate step. The second, convergent approach relies on the symmetry of the targets: it includes suitably activated subunits, which are subjected to macrocyclization conditions. The subunits first oligomerize, then cyclize to form either pure macrolactams or mixtures. The macrolactam units 1, 2 and 4 stack on top each other through weak interactions (hydrogen bond and van der Waals), to form endless square, rectangular and triangular prisms, respectively. These stacks are further packed side by side in crystals grown from isotropic media. The overall dipoles in the crystals from lactams 1 and 4, which result mostly from the alignment of amide groups, are zero and large, respectively. Macrolactam 2 displays an astonishing isomorphism when allowed to cool down in anisotropic liquid crystal solutions. Large hollow hexagonal tubes are then obtained through a fractal process. Contrary to the three previous rings, 3 yields crystals where prisms of any shape are absent.

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Section: Resultsmentioning

confidence: 99%

Efficient Synthesis and Astonishing Supramolecular Architectures of Several Symmetric Macrolactams

Baillargeon

Bernard

Gauthier

et al. 2007

Chemistry A European J

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“…The macrocycle 1 was prepared from the thioester 3 with a silver( I ) salt in 55 % yield 23. The thioester 3 was obtained from the Boc‐protected amino acid 2 in six straightforward steps (overall yield of 83 %) 24. The material was easily crystallized by diffusion (ethanol and diethyl ether) and X‐ray crystallography showed that 1 and cyclohexaglycine pack in a very similar way.…”

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confidence: 99%

Self-Assembly of Cyclic Peptides into Nanotubes and Then into Highly Anisotropic Crystalline Materials

et al. 2001

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Syntheses of supermolecules rely on the stabilization provided by noncovalent interactions between recognition sites in each unit. [1±3] The construction of new supramolecular architectures with well-defined shape and size by using tube building blocks is an important subject in organic materials chemistry because novel electronic and photonic properties can result from their three-dimensional (3D) organization (Figure 1 a). [2] These tubular structures have also attracted considerable interest because of their utility as models for biological channels. [4±9] It is also thought that in tubes built from stacked cyclic peptides, uniform alignment of amide groups could give rise to a macrodipole moment such as that of an a-helix. [10] Voltage gating and current rectification are important expected new properties for such channel structures. [11] To date, all attempts to grow crystals of a useful size were frustrated by the inherent insolubility of these materials. [12±15] compared to the barriers for the respective ammine proton transfer reactions results from the increased distortion of the core structures in the transition states and the lower acidity of the amide protons. Zero point vibration and entropic contributions lower the Gibbs free energy barrier difference between the two pathways to 54 ± 63 kJ mol À1 by destabilizing the highly ordered ammine proton transfer transition states 12, 18, and 24. This difference could well be overcome by steric congestion induced by bulky substituents of amines and unsaturated hydrocarbon substrates. For comparison, the steric destabilization for complexes with three 2,6-dimethylanilide ligands at a titanium center such as in 4 a and 5 a has been computed to be 67 ± 78 kJ mol À1 .In allene and ethyne hydroamination with the simplified [CpTiNH(NH 2 )] system, where proton transfer takes place after initial amine coordination, the transition state for the cycloaddition is the highest point in the catalytic pathway and thus is rate-determining. However, it remains unclear whether the zero-order dependence on the 2,6-dimethylaniline concentration derived from the kinetic data for allene hydroamination [4] results from a rate-determining [22] cycloaddition or a rate-determining proton transfer from an amide ligand. A first-order dependence on the amine concentration can occur if the Gibbs free activation energy for the amine coordination plus proton transfer pathway is higher than the barrier for the initial [22] cycloaddition, but lower than the barrier for a competing amide proton transfer. A ratedetermining amide ligand exchange with free amine could also result in such a rate law (see Supporting Information for computed ligand exchange pathways).For alkene hydroamination, our model calculations predict that both the ammine and the amide proton transfer to the TiÀC bond have Gibbs free activation energies that are more than 50 kJ mol À1 higher than the cycloaddition step ( Figure 4 and 5 c). This explains the relative ease of allene and alkyne hydroamination compared to...

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“…The glycine–glycine ( E )‐alkene dipeptide isostere (abbreviated as ψ [( E )‐CHCH]) was synthesised by a Schmidt rearrangement of ( E )‐3‐hexenedioic acid according to an instruction by Allan and co‐workers 10. The subsequent coupling of a Fmoc protecting group to the amine function under standard conditions led us to a building block (41 % yield over two steps), which could be incorporated into the backbone of the linear peptide precursor.…”

Section: Methodsmentioning

confidence: 99%

Enzymatic Cyclisation of Peptidomimetics with Incorporated (E)‐Alkene Dipeptide Isosteres

Garbe¹,

Sieber²,

Bandur³

et al. 2004

ChemBioChem

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Synthesis of Analogues of GABA. XIV. Synthesis and Activity of Unsaturated Derivatives of 5-Aminopentanoic Acid (d-Aminovaleric Acid)

Cited by 25 publications

References 0 publications

Efficient Synthesis and Astonishing Supramolecular Architectures of Several Symmetric Macrolactams

Efficient Synthesis and Astonishing Supramolecular Architectures of Several Symmetric Macrolactams

Self-Assembly of Cyclic Peptides into Nanotubes and Then into Highly Anisotropic Crystalline Materials

Enzymatic Cyclisation of Peptidomimetics with Incorporated (E)‐Alkene Dipeptide Isosteres

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