Synthesis of a novel, conformationally restricted analog of tryptophan

Franceschetti, L.; Garzon-Aburbeh, A.; Mahmoud, Mahmoud R.; Natalini, Benedetto; Pellicciari, Roberto

doi:10.1016/s0040-4039(00)93413-0

Cited by 16 publications

(3 citation statements)

References 10 publications

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“…Synthetic routes to cyclopent[ b ]indol-2(1 H )-ones and cyclopent[ b ]indol-1,2(3 H ,4 H )-diones on the other hand are rare. The tricyclic ketones have been obtained in low to good yield by the Fischer indole synthesis and by different ring-closing strategies for the formation of the five-membered ring annulated to the indole system. ,− …”

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confidence: 99%

Total Synthesis of Nostodione A, a Cyanobacterial Metabolite

2012

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The first total synthesis of the mitotic spindle poison nostodione A is described. The inherent oxidative sensitivity of indoles is utilized for a late introduction of a second carbonyl to the cyclopent[b]indole-2-one system. The tricyclic system is prepared from indole-3-acetic acid and O-silylated 4-ethynylphenol, using a stereoselective intramolecular reductive Heck cyclization as the key transformation.

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confidence: 99%

Total Synthesis of Nostodione A, a Cyanobacterial Metabolite

2012

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“…[22,23] In this way, the imidoyl tryptophanate 9 participates as an activated carboxylic acid, and we note that there are several examples in the literature where the carboxylic acid carbonyl group of N b -acyltryptophan derivatives have undergone ring-closure to give cyclopenta[b]indolones, [24] although these have normally required the use of FriedelϪCrafts acylation conditions. We note that in comparison to other N b -acyltryptophan derivatives undergoing the BischlerϪNapieralski reaction, the iminium ion generated from -tryptophan present here has restricted mobility, being locked in an otherwise planar oxazolone ring, itself tethered by a single methylene bridge to the indole moiety to which the iminium ion reacts, and containing a bulky trichloromethyl substituent at C-2.…”

Section: Methodsmentioning

confidence: 97%

Reactivity of β‐Carbolines and Cyclopenta[b]indolones Prepared from the Intramolecular Cyclization of 5(4H)‐Oxazolones Derived from L‐Tryptophan

Condie¹,

Bergman²

2004

Eur J Org Chem

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Keywords: 5(4H)-Oxazolone / β-Carboline / Cyclopenta [b]indolone / Cyclization / BischlerϪNapieralski reaction / Canthine / Synthesis design 4-(1H-Indol-3-ylmethyl)-2-trichloromethyl-1,3-oxazol-5(4H)-one (4) was shown to undergo an intramolecular reaction in the presence of TFA, to afford a β-carboline 5 and a cyclopenta[b]indolone 6 by nucleophilic addition at C-2 and C-5, respectively. The distribution of these two products was found to be dependent on the reaction temperature, with lower temperatures favouring the formation of the β-carboline 5. Subsequent reactions performed on the β-carboline 5 led to the formation of canthine and canthin-6-one derivatives.

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“…Solvent removal gave an off-white solid, mp 172 °C; lit. mp 170 °C . IR (KBr): 3405, 1675, 1438, 1202, 1139.…”

Section: Methodsmentioning

confidence: 99%

Conformer Interconversion in the Excited State of Constrained Tryptophan Derivatives

McMahon

Vela

et al. 1997

J. Phys. Chem. B

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The conformer model of tryptophan photophysics ascribes the multiple fluorescence lifetimes to ground-state heterogeneity. It is usually assumed that the different conformers do not interconvert in the excited state. Previous studies of two constrained tryptophan derivatives supported this assumption (Colucci, W. J.; Tilstra, L.; Sattler, M. C.; Fronczek, F. R.; Barkley, M. D. J. Am. Chem. Soc. 1990, 112, 9182−9190; Yu, H.-T.; Vela, M. A.; Fronczek, F. R.; McLaughlin, M. L.; Barkley, M. D. J. Am. Chem. Soc. 1995, 117, 348−357). Five constrained derivatives have been synthesized and shown to undergo conformer inversion during the lifetime of the excited state. All derivatives have two ground-state conformations as determined by X-ray crystallography, molecular mechanics calculations, and 1H-NMR. Fluorescence lifetime data were fit to single- and double-exponential models and to a reversible two-state excited-state reaction model. 2-Amino-1,2-dihydrocyclopenta[b]indole-2-carboxylic acid has a single-exponential decay consistent with conformer inversion much faster than fluorescence decay. 1,2,3,4-Tetrahydrocarbazole-3-carboxylic acid, ethyl 1,2,3,4-tetrahydrocarbazole-3-carboxylate, and their 9-methyl derivatives have double-exponential decays with a minor second component of small positive or negative amplitude. Conformer inversion rates of ∼107 s-1 were determined by analyzing the fluorescence decay data using the excited-state reaction model. Temperature dependence of the fluorescence lifetimes was measured in H2O and D2O, and solvent quenching rates were calculated from the Arrhenius parameters. The carboxylate and carbonyl functional groups appear to have little effect on solvent quenching of indole fluorescence. Model calculations examining the effect of conformer inversion rate on the decay parameters of a biexponential model indicate that the presence of a small amplitude, short lifetime component may be a good predictor of excited-state conformer interconversion of tryptophans in peptides and proteins.

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Synthesis of a novel, conformationally restricted analog of tryptophan

Cited by 16 publications

References 10 publications

Total Synthesis of Nostodione A, a Cyanobacterial Metabolite

Total Synthesis of Nostodione A, a Cyanobacterial Metabolite

Reactivity of β‐Carbolines and Cyclopenta[b]indolones Prepared from the Intramolecular Cyclization of 5(4H)‐Oxazolones Derived from L‐Tryptophan

Conformer Interconversion in the Excited State of Constrained Tryptophan Derivatives

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