Efficient Route to (<i>S</i>)-Azetidine-2-carboxylic Acid

Futamura, Yasuhiko; Kurokawa, Masayuki; Obata, Rika; Nishiyama, Shigeru; Sugai, Takeshi

doi:10.1271/bbb.69.1892

Cited by 20 publications

(11 citation statements)

References 19 publications

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“…S-azetidine-2-carboxylic acid is a non-natural amino acid that has chemical and biochemical applications [41][42][43][44][45][46] ͓see Fig. 2͑a͔͒.…”

Section: S-azetidine-2-carboxylic Acidmentioning

confidence: 99%

Using the ONIOM hybrid method to apply equation of motion CCSD to larger systems: Benchmarking and comparison with time-dependent density functional theory, configuration interaction singles, and time-dependent Hartree–Fock

Caricato

Vreven

Trucks

et al. 2009

The Journal of Chemical Physics

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Assessment of time-dependent density functional schemes for computing the oscillator strengths of benzene, phenol, aniline, and fluorobenzene J. Chem. Phys. 127, 084103 (2007) Equation of motion coupled-cluster singles and doubles ͑EOM-CCSD͒ is one of the most accurate computational methods for the description of one-electron vertical transitions. However, its O͑N 6 ͒ scaling, where N is the number of basis functions, often makes the study of molecules larger than 10-15 heavy atoms prohibitive. In this work we investigate how accurately less expensive methods can approximate the EOM-CCSD results. We focus on our own N-layer integrated molecular orbital molecular mechanics ͑ONIOM͒ hybrid scheme, where the system is partitioned into regions which are treated with different levels of theory. For our set of benchmark calculations, the comparison of conventional configuration interaction singles ͑CIS͒, time-dependent Hartree-Fock ͑TDHF͒, and time-dependent density functional theory ͑TDDFT͒ methods and ONIOM ͑with different low level methods͒ showed that the best accuracy-computational time combination is obtained with ONIOM͑EOM:TDDFT͒, which has a rms of the error with respect to the conventional EOM-CCSD of 0.06 eV, compared with 0.47 eV of the conventional TDDFT.

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“…S-azetidine-2-carboxylic acid is a non-natural amino acid that has chemical and biochemical applications [41][42][43][44][45][46] ͓see Fig. 2͑a͔͒.…”

Section: S-azetidine-2-carboxylic Acidmentioning

confidence: 99%

Using the ONIOM hybrid method to apply equation of motion CCSD to larger systems: Benchmarking and comparison with time-dependent density functional theory, configuration interaction singles, and time-dependent Hartree–Fock

Caricato

Vreven

Trucks

et al. 2009

The Journal of Chemical Physics

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“…The above compounds were not traced in the literature for the genus Delonix. Compound 9 was identified as L-azeditine-2carboxylic acid, its structure was confirmed by comparing its chromatographic data (IR, 1 H-NMR and 13 C-NMR) with that reported in the literature [30] . Compound 9 was isolated before from the legumes of the same plant [31] .…”

Section: Discussionmentioning

confidence: 69%

Hepatoprotective and cytotoxic activities of Delonix regia flower extracts

El-Sayed

Ezzat

Salama

et al. 2011

Pharmacognosy Journal

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A B S T R A C TFractionation of the ethanolic extract of the flowers of Delonix regia led to the isolation of three sterols, namely, stigmasterol (1.54 %), β-sitosterol and its 3-O-glucoside (6.93 %), a triterpene, namely, ursolic acid (3.61 %) and four flavonoids: quercetin (2.92 %), quercitrin (0.59 %), isoquercitrin (3.87 %) and rutin (5.12 %) in addition to the amino acid L-azeditine-2-carboxylic acid. The structures of the isolated compounds were established on the basis of physicochemical properties and spectral analysis (IR, UV, EI/MS, 1 H-NMR and 13 C-NMR). The concentration of the isolated compounds was determined by HPLC technique. The ethanolic extract and its non-polar and flavonoid rich fraction as well as the isolated compounds evidenced cytotoxic activities against human liver cancer cell line (HEPG2) which were potent for ursolic acid (IC 50 0.55 µg/ml) and L-azeditine-2-carboxylic acid (IC 50 2.51 µg/ml). Meanwhile, rutin and isoquercitrin were inactive. Moreover, the ethanolic extract and its two fractions were tested for hepatoprotective activity against CCl 4 induced hepatic cell damage in rats at two dose levels (50 and 100 mg/kg), and the flavonoid rich fraction showed statistically significant hepatoprotection at 100 mg/kg. The presence of the aforementioned flavonoids with their efficient free radical scavenging properties may explain this liver protection ability. This could suggest the use of the ethanolic extract of the flowers of D. regia as a chemopreventive agent against the two main causes of liver damage; liver toxicity by chlorinated agents and liver cancer.

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“…Final hydrogenolysis and recrystallization allowed the isolation of (S)-127 in enantiomerically pure form. 101 Proline derivatives constitute probably the most employed family of organocatalysts in asymmetric synthesis but also present remarkable applications in medicinal chemistry or as building blocks for more complex structures. The research group of Kazlauskas studied the hydrolysis of protonated proline methyl ester (()-128 (Scheme 45) using different preparations of lipase from Aspergillus niger (ANL).…”

Section: Modifications At the Carboxylic Groupmentioning

confidence: 99%