Definitive assignment of <sup>13</sup>C NMR signals in tryptophan and related molecules

Morales‐Ríos, Martha S.; Joseph‐Nathan, Pedro

doi:10.1002/jhet.5570230602

Cited by 12 publications

(3 citation statements)

References 26 publications

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“…The 1 H and 13 C chemical shift assignments of the compounds are straightforward from the multiplicity patterns and resonance intensities, and are consistent with the literature 12, 29, 30. The NH proton of the indole ring appears as a broad singlet in the range of δ 8.14–8.51 ppm.…”

Section: Resultssupporting

confidence: 86%

Synthesis, characterization and cytotoxic activity of new diorganotin(IV) complexes of N‐(3,5‐dibromosalicylidene)tryptophane

Tian

Liu

Zheng

et al. 2011

Applied Organom Chemis

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Four new diorganotin(IV) complexes of N-(3,5-dibromosalicylidene)tryptophane, R 2 Sn[3,5-Br 2 -2-OC 6 H 2 CH NCH(CH 2 Ind)COO] [Ind = 3-indolyl; R = Et (1); n-Bu (2); Cy (3); Ph (4)], were synthesized and characterized by elemental analysis and IR, NMR ( 1 H, 13 C and 119 Sn) spectra. The crystal structures of complexes 1-3 were determined by X-ray single crystal diffraction. The tin atom is five-coordinated and its coordination geometry is best described as an intermediate between trigonal bipyramidal and square pyramidal. Intermolecular weak interactions in the complexes 1-3 connect molecules into a one-dimensional helical chain and a two-dimensional array. The dibutyltin complex 2 has potent in vitro cytotoxic activity against two human tumor cell lines, CoLo205 and Bcap37, while the diethyltin complex 1 displays weak cytotoxic activity.

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Section: Resultssupporting

confidence: 86%

Synthesis, characterization and cytotoxic activity of new diorganotin(IV) complexes of N‐(3,5‐dibromosalicylidene)tryptophane

Tian

Liu

Zheng

et al. 2011

Applied Organom Chemis

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“…The 13 C-NMR assignments of the indole ring have been subject to some controversy, particular those of C-4, C-5 and C-6 that are often found very close to each other. 54,55 In d 6 -DMSO the chemical shifts for C-4 and C-5 in UTs are either the same or very close (Table 8), therefore their exact assignments were impossible. The corresponding assignments in CDCl 3 however, are possible as shown in Table S4.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

Analytical chemistry of synthetic routes to psychoactive tryptamines : Part II. Characterisation of the Speeter and Anthony synthetic route to N,N-dialkylated tryptamines using GC-EI-ITMS, ESI-TQ-MS-MS and NMR

Brandt¹,

Freeman

Fleet

et al. 2005

Analyst

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The degree of alkylation of the side chain nitrogen in tryptamines is one important factor that affects psychoactivity. The method of Speeter and Anthony is considered to be one of the most important synthetic preparative methods. The final step in this reaction is based on the reduction of a (substituted) indole-3-yl-glyoxalylamide to the desired tryptamine with metal hydride. Twelve symmetrically and 13 asymmetrically N,N-disubstituted glyoxalylamides and their corresponding tryptamine derivatives have been synthesised and characterised by gas chromatography EI-ion trap mass spectrometry, electrospray-triple quadrupole-tandem mass spectrometry and NMR spectroscopy. Mass spectral and NMR similarities and differences between the investigated compounds are discussed. A solvent dependency is observed that has to be taken into consideration for the unambiguous assignment of (1)H- and (13)C-NMR chemical shifts. The (1)H-NMR study demonstrated that one can evaluate the rotamer populations of the asymmetrical glyoxalylamides. In a forensic or clinical scenario where single or multiple reaction monitoring approaches are contemplated, the appropriate ion transitions of choice may then focus on the two main fragmentations, namely beta-cleavage ([M+H](+)-->CH(2)N(+)R(2)R(3)) and/or alpha-cleavage ([M+H](+)-->[3-vinylindole](+)), respectively. The synthesis, NMR and MS analytical data presented provide the forensic analyst and clinical biochemist with a detailed and self-consistent body of information and mechanisms for the spectral identification of the more likely psychoactive tryptamines that may be met.

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“…Thus, for 5 this allows the assignment of the lower field double doublet at 8. 11 The data show that C-4 absorbs at considerably higher field than C-6. The chemical shift difference between the c o n t r~v e r s i a l~-~ carbons 4 and 6 is large enough (ca 12.0 ppm) to provide unequivocal assignments, regardless of the substituent at the N-1, C-2 and/or C-3 positions of the indole skeleton.…”

Section: Resultsmentioning

confidence: 90%

NMR studies of indoles and their N‐carboalkoxy derivatives

Morales‐Ríos¹,

Joseph‐Nathan²

1987

Magnetic Reson in Chemistry

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The 13C NMR assignment of indoles and 5-methoxyindoles substituted at position 3, and some of their N-carboalkoxy derivatives, was achieved from one-and two-dimensional NMR experiments. Substituent chemical shifts and 'J(CH) values were evaluated. The dynamic processes of N-carboalkoxyindoles and N-carboalkoxyindoline observed by high-field 'H NMR show the existence of two preferred rotamers around the carbamate N-C(=O)OR bond, which was interpreted in terms of frequency/field strength-dependent phenomena.

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Definitive assignment of ¹³C NMR signals in tryptophan and related molecules

Abstract: Selective photodeuteration of carboxyltryptamines at C‐4 allowed to settle the controversy about the 13C nmr assignment of C‐4, C‐5 and C‐6, which for tryptophan are definitively assigned at 118.4, 118.2 and 120.6 ppm, respectively.

Cited by 12 publications

References 26 publications

Synthesis, characterization and cytotoxic activity of new diorganotin(IV) complexes of N‐(3,5‐dibromosalicylidene)tryptophane

Synthesis, characterization and cytotoxic activity of new diorganotin(IV) complexes of N‐(3,5‐dibromosalicylidene)tryptophane

Analytical chemistry of synthetic routes to psychoactive tryptamines : Part II. Characterisation of the Speeter and Anthony synthetic route to N,N-dialkylated tryptamines using GC-EI-ITMS, ESI-TQ-MS-MS and NMR

NMR studies of indoles and their N‐carboalkoxy derivatives

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Definitive assignment of 13C NMR signals in tryptophan and related molecules

Abstract: Selective photodeuteration of carboxyltryptamines at C‐4 allowed to settle the controversy about the 13C nmr assignment of C‐4, C‐5 and C‐6, which for tryptophan are definitively assigned at 118.4, 118.2 and 120.6 ppm, respectively.

Cited by 12 publications

References 26 publications

Synthesis, characterization and cytotoxic activity of new diorganotin(IV) complexes of N‐(3,5‐dibromosalicylidene)tryptophane

Synthesis, characterization and cytotoxic activity of new diorganotin(IV) complexes of N‐(3,5‐dibromosalicylidene)tryptophane

Analytical chemistry of synthetic routes to psychoactive tryptamines : Part II. Characterisation of the Speeter and Anthony synthetic route to N,N-dialkylated tryptamines using GC-EI-ITMS, ESI-TQ-MS-MS and NMR

NMR studies of indoles and their N‐carboalkoxy derivatives

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Definitive assignment of ¹³C NMR signals in tryptophan and related molecules