The Crystal Structures of <scp>l</scp>-Tryptophan Hydrochloride and Hydrobromide

Takigawa, Takaji; Ashida, Tamaichi; Sasada, Yoshio; Kakudo, Masao

doi:10.1246/bcsj.39.2369

Cited by 103 publications

(81 citation statements)

References 10 publications

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“…The 'solid' CT π/2 pulse used for amino acid hydrochlorides was therefore 2.2 µs. Chemical shifts were 40 This is the model used for quantum chemical calculations in the present work, consisting of one chloride ion and four tryptophan moieties. The chloride ion forms hydrogen bonds with three NH 3 + groups and with one OH group.…”

Section: Methodsmentioning

confidence: 99%

Chlorine-35/37 NMR Spectroscopy of Solid Amino Acid Hydrochlorides: Refinement of Hydrogen-Bonded Proton Positions Using Experiment and Theory

2006

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Trends in the chlorine chemical shift (CS) tensors of amino acid hydrochlorides are investigated in the context of new data obtained at 21.1 T and extensive quantum chemical calculations. The analysis of chlorine-35/37 NMR spectra of solid L-tryptophan hydrochloride obtained at two magnetic field strengths yields the chlorine electric field gradient (EFG) and CS tensors, and their relative orientations. The chlorine CS tensor is also determined for the first time for DL-arginine hydrochloride monohydrate. The drastic influence of 1 H decoupling at 21.1 T on the spectral features of salts with particularly small 35 Cl quadrupolar coupling constants (C Q ) is demonstrated. The chlorine CS tensor spans (Ω) of hydrochloride salts of hydrophobic amino acids are found to be larger than those for salts of hydrophilic amino acids. A new combined experimental-theoretical procedure is described in which quantum chemical geometry optimizations of hydrogen-bonded proton positions around the chloride ions in a series of amino acid hydrochlorides are cross-validated against the experimental chlorine EFG and CS tensor data. The conclusion is reached that the relatively computationally inexpensive B3LYP/ 3-21G* method provides proton positions which are suitable for subsequent higher-level calculations of the chlorine EFG tensors. The computed value of Ω is less sensitive to the proton positions. Following this cross-validation procedure, |C Q ( 35 Cl)| is generally predicted within 15% of the experimental value for a range of HCl salts. The results suggest the applicability of chlorine NMR interaction tensors in the refinement of proton positions in structurally similar compounds, e.g., chloride ion channels, for which neutron diffraction data are unavailable. IntroductionThe availability of high-field solid-state nuclear magnetic resonance (NMR) spectrometers, e.g., those with 1 H resonance frequencies of 800 MHz, 900 MHz, and above, has created new opportunities for the study of quadrupolar nuclei (I > 1/ 2) with low resonance frequencies or large quadrupole moments, and for nuclei with both of these properties. For example, Stebbins et al. have described applications of 18.8 and 21.1 T solid-state 27 Al, 17 O, 39 K, and 35 Cl NMR spectroscopy to study oxide materials. 1-3 Gan et al. used magnetic fields as high as 40 T to achieve chemical shift resolution between four different aluminum environments in aluminoborate. 4 Ellis and colleagues have applied high-field 67 Zn NMR at low temperature to study zinc binding environments of biological relevance. 5,6,7,8 Magicangle-spinning (MAS) NMR in a magnetic field of 19.6 T has been applied by Wu and co-workers to detect potassium cations in guanine-quadruplex structures 9 as well as to explore cation-π interactions in alkali metal tetraphenylborates. 10 Cross and coworkers have demonstrated the utility of 17 O solid-state NMR at 21.1 T for characterizing the ion channel gramicidin. 11,12 The major reason that higher fields are so beneficial for the study of quadrupolar nuclei in ...

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Section: Methodsmentioning

confidence: 99%

Chlorine-35/37 NMR Spectroscopy of Solid Amino Acid Hydrochlorides: Refinement of Hydrogen-Bonded Proton Positions Using Experiment and Theory

2006

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“…This kind of molecular arrangement is characteristic for structures containing both polar and non-polar groups together. L-Tryptophane hydrochloride (Takigawa, Ashida, Sasada & Kakudo, 1966;Andrews, Farkas, Frey, Lehmann & Koetzle, 1974) and glycine hydrochloride (AI-Karaghouli, Cole, Lehmann, Miskell, Verbist & Koetzle, 1975) Baur (1972). Thus H 3 cannot be envisaged to form a 'bifurcated' hydrogen bond as suggested by Gurskaya (1965) on the basis of the X-ray O-N distances.…”

Section: Ca--c V -C ¢Tmentioning

confidence: 99%

Neutron diffraction study of L-phenylalanine hydrochloride

Al-Karaghouli¹,

Koetzle²

1975

Acta Crystallogr Sect B

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“…Copies may be obtained through the Executive Secretary, International Union of Crystallography, 13 White Friars, Chester CHI 1NZ, England. PICRATE AND D,L-TRYPTOPHAN PICRATE-METHANOL structure of L-tryptophan hydrochloride (Takigawa, Ashida, Sasada & Kakudo, 1966). The carboxyl group and atom C(11) [Ca] are coplanar and the torsion angle N(11)-C(11)-C(12)-O'(12), which is a measure of the deviation of the amino nitrogen atom from the carboxyl plane, is -28°.…”

Section: Table 5 Selected Torsion Angles For the Tryptamine And Trypmentioning

confidence: 99%

Crystal structures of tryptamine picrate and D,L-tryptophan picrate–methanol, two indole donor–acceptor complexes

Gartland¹,

Freeman²,

Bugg³

1974

Acta Crystallogr Sect B

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The crystal structures of the red picric acid salts of tryptamine and of D,L-tryptophan-methanol were determined by X-ray diffraction methods. Crystals of tryptamine picrate (C10HIaN2.C6H2N307) are monoclinic, space group P21/c, with a= 15.927 (2), b=6.913 (1), c=21.841 (2) A, fl= 133.88 (1) ° and Z= 4. Crystals of O,L-tryptophan picrate-methanol (C11HI3N202. C6H2N307. CH40) are triclinic, space group P1, with a= 11-733 (1), b= 11-547 (1), c=7.971 (1) ,~, a= 100.34 (3), fl=81.31 (1), y=97.98 (2) °, and Z--2. Three-dimensional X-ray intensity data (2882 reflections for the tryptamine complex and 3458 reflections for the tryptophan complex) were measured with an automated diffractometer by use of nickel-filtered copper radiation. Trial structures, obtained by direct methods, were refined by leastsquares calculations to R indices of 0.056 and 0.088 for the tryptamine and tryptophan complexes, respectively. Both crystal structures contain distinct indole-picrate pairs. The indole and picrate planes are stacked, with interplanar spacings of 3.3-3.5 A. The stacking interaction appears to be of the donoracceptor (charge-transfer) type. However, contrary to the continous columns of stacked rings usually found in crystal structures of aromatic donor-acceptor complexes, the stacked indole-picrate pairs are relatively isolated and without re-re interactions between adjacent pairs. The stacking patterns are similar in the tryptamine and tryptophan complexes. The tryptamine and tryptophan cations assume the same conformation found for serotonin in the crystal structure of the serotonin picrate monohydrate donor-acceptor complex.

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The Crystal Structures of l-Tryptophan Hydrochloride and Hydrobromide

Cited by 103 publications

References 10 publications

Chlorine-35/37 NMR Spectroscopy of Solid Amino Acid Hydrochlorides: Refinement of Hydrogen-Bonded Proton Positions Using Experiment and Theory

Chlorine-35/37 NMR Spectroscopy of Solid Amino Acid Hydrochlorides: Refinement of Hydrogen-Bonded Proton Positions Using Experiment and Theory

Neutron diffraction study of L-phenylalanine hydrochloride

Crystal structures of tryptamine picrate and D,L-tryptophan picrate–methanol, two indole donor–acceptor complexes

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