Search results

Items from 1 to 20 out of 622 results

article

A new 3,4-seco-oleanane-type triterpenoid with an unusual enedione moiety from Hypericum ascyron

Chunmei Chen, Guangzheng Wei, Hucheng Zhu, Yi Guo, more

Fitoterapia > 2015 > 103 > Complete > 227-230

A novel 3,4-seco-oleanane-type triterpenoid named 3,4-seco-olean-13(18)-ene-12,19-dione-3-oic acid (1), bearing an unusual enedione moiety, was isolated from the aerial parts of Hypericum ascyron, together with a known feiedelane-type triterpenoid friedelin (2). The structure of 1 with absolute configuration was elucidated on the basis of spectroscopic methods and a single-crystal X-ray diffraction...

article

Bis-spirolabdane diterpenoids from Leonurus japonicus and their anti-platelet aggregative activity

Liang Xiong, Qin-Mei Zhou, Cheng Peng, Xiao-Fang Xie, more

Fitoterapia > 2015 > 100 > Complete > 1-6

Six bis-spirolabdane diterpenoids along with four known analogues were isolated from the aerial parts of Leonurus japonicus. Their structures and absolute configurations were elucidated by spectroscopic analyses, single-crystal X-ray diffraction, and a modified Mosher's method. The inhibitory activity of the compounds against the abnormal increase in platelet aggregation induced by adenosine diphosphate...

article

Total synthesis of epicoccamides A and D via olefin cross-metathesis

Arata Yajima, Akihiro Kawajiri, Ayaka Mori, Ryo Katsuta, more

Tetrahedron Letters > 2014 > 55 > 31 > 4350-4354

Epicoccamides A and D were synthesized through a route that utilizes fragment coupling via olefin cross-metathesis as a key step. The right-hand segment of the epicoccamides was synthesized by a tandem O-acylation–migration reaction, and the left-hand segments were stereoselectively synthesized through a modified version of Crich’s β-selective mannosylation. The previously assigned absolute configuration...

article

Novel nardosinane type sesquiterpenoids from Nardostachys chinensis Batal

Jin-Bo Zhang, Ming-Li Liu, Ying-Hui Duan, Hai-Yan Tian, more

Tetrahedron > 2014 > 70 > 30 > 4507-4511

Five new sesquiterpenoids Nardosinanone A–E (1–5), were isolated from the extract of Nardostachys chinensis, and their structures were determined by extensive spectroscopic analysis. Compound 1 featured a nardosinane sesquiterpenoid with an unusual tricyclic skeleton. Compounds 2–4 were new nardosinane sesquiterpenoids bearing a rare 10,11-epoxy group. The absolute configurations were determined by...

article

Anti‐inflammatory Steroids from the South China Sea Sponge Spongia officinalis

Jiao Liu, Zi‐Yi Liu, Yan Fu, Yu‐Cheng Gu, more

Chemistry & Biodiversity > 21 > 6 > n/a - n/a

One new highly degraded steroid, namely 21‐nor‐4‐ene‐chaxine A (1) furnishing a 5/6/5‐tricyclic, along with one known related analogue (2), were isolated from the South China Sea sponge Spongia officinalis. Their structures including absolute configurations were established by extensive spectroscopic data analysis, TDDFT‐ECD calculation, and comparison with the spectral data previously reported in...

article

Circular Dichroism Sensing: Strategies and Applications

Jeffrey S. S. K. Formen, James R. Howard, Eric V. Anslyn, Christian Wolf

Angewandte Chemie International Edition > 63 > 19 > n/a - n/a

The analysis of the absolute configuration, enantiomeric composition, and concentration of chiral compounds are frequently encountered tasks across the chemical and health sciences. Chiroptical sensing methods can streamline this work and allow high‐throughput screening with remarkable reduction of operational time and cost. During the last few years, significant methodological advances with innovative...

article

Circular Dichroism Sensing: Strategies and Applications

Jeffrey S. S. K. Formen, James R. Howard, Eric V. Anslyn, Christian Wolf

Angewandte Chemie > 136 > 19 > n/a - n/a

article

An Artificial Intelligence Approach for Tackling Conformational Energy Uncertainties in Chiroptical Spectroscopies

Gabriel Marton, Mark A. J. Koenis, Hong‐Bing Liu, Carole A. Bewley, more

Angewandte Chemie International Edition > 62 > 38 > n/a - n/a

Determination of the absolute configuration of chiral molecules is a prerequisite for obtaining a fundamental understanding in any chirality‐related field. The interaction with polarised light has proven to be a powerful means to determine this absolute configuration, but its application rests on the comparison between experimental and computed spectra for which the inherent uncertainty in conformational...

article

Cover Picture: An Artificial Intelligence Approach for Tackling Conformational Energy Uncertainties in Chiroptical Spectroscopies (Angew. Chem. Int. Ed. 38/2023)

Gabriel Marton, Mark A. J. Koenis, Hong‐Bing Liu, Carole A. Bewley, more

Angewandte Chemie International Edition > 62 > 38 > n/a - n/a

The assignment of the absolute configuration of chiral compounds critically depends on the comparison with predictions of chiroptical spectra with intrinsically inaccurate quantum chemical calculations. Wybren Jan Buma, Valentin Paul Nicu et al. report in their Research Article (e202307053) a novel protocol based on genetic algorithm analyses and hierarchical clustering that overcomes these inaccuracies...

article

Titelbild: An Artificial Intelligence Approach for Tackling Conformational Energy Uncertainties in Chiroptical Spectroscopies (Angew. Chem. 38/2023)

Gabriel Marton, Mark A. J. Koenis, Hong‐Bing Liu, Carole A. Bewley, more

Angewandte Chemie > 135 > 38 > n/a - n/a

article

An Artificial Intelligence Approach for Tackling Conformational Energy Uncertainties in Chiroptical Spectroscopies

Gabriel Marton, Mark A. J. Koenis, Hong‐Bing Liu, Carole A. Bewley, more

Angewandte Chemie > 135 > 38 > n/a - n/a

article

Absolute Configuration Determination of Chiral API Molecules by MicroED Analysis of Cocrystal Powders Formed Based on Cocrystal Propensity Prediction Calculations**

Harsh S. Shah, Jiuchuang Yuan, Tian Xie, Zhuocen Yang, more

Chemistry – A European Journal > 29 > 14 > n/a - n/a

Establishing the absolute configuration of chiral active pharmaceutical ingredients (APIs) is of great importance. Single crystal X‐ray diffraction (scXRD) has traditionally been the method of choice for such analysis, but scXRD requires the growth of large crystals, which can be challenging. Here, we present a method for determining absolute configuration that does not rely on the growth of large...

article

Structures and absolute configurations of excoecoumarins A and B studied by experimental and theoretical NMR and circular dichroism spectra

Mu‐Fong Chang, Jia‐Lin Chang, Chih‐Yang Cheng, Ho‐Cheng Wu, more

Journal of Physical Organic Chemistry > 36 > 3 > n/a - n/a

The structures and absolute configurations of two organic compounds, excoecoumarin A and excoecoumarin B, were studied by recording their electronic circular dichroism (ECD) spectra and performing quantum‐chemistry computations. The optical rotations and the nuclear magnetic resonance (NMR), ECD, vibrational circular dichroism (VCD), and ultraviolet (UV) spectra of candidate structures were computed...

article

Total Synthesis, Absolute Configuration, and Phytotoxic Activity of Foeniculoxin

Akane Yamagishi, Yuki Egoshi, Makoto T. Fujiwara, Noriyuki Suzuki, more

Chemistry – A European Journal > 29 > 8 > n/a - n/a

Foeniculoxin is a major phytotoxin produced by Italian strains of Phomopsis foeniculi. The first total synthesis is described utilizing the ene reaction and Sonogashira cross‐coupling reaction as key steps. The absolute configuration of the C6’ was determined using chiral separation and an advanced Mosher's method. The phytotoxicity of the synthesized compound was demonstrated via syringe‐based infiltration...

article

Propeller, Linear, Cruciform and Stellate Spiro‐bicarbazolium Salts

Mengsi Lu, Jun Xu, Kim K. Baldridge, Jay S. Siegel

Chemistry – A European Journal > 29 > 6 > n/a - n/a

A general synthetic approach to halogenated tetraaryl‐ammonium salts has been developed and illustrated crystallographically. Bromide ammonium salts used as common synthetic intermediates together with Suzuki coupling of these bromides to a family of boronic acids provided a simplified strategy for arylation. Resolution of the C₂ subset of spiro‐bicarbazolium derivatives led to the first examples...

article

Otrzymywanie i właściwości biologiczne racemicznych i optycznie czynnych laktonów z pierścieniem aromatycznym w pozycji β

Witold Gładkowski

Wiadomości Chemiczne > 2023 > [Z] 77, 5-6 > 509--531

Natural and synthetic lactones containing an aromatic ring exhibit a number of biological properties, e.g. antiproliferative, antifeedant or antimicrobial activity. This review deals with the synthesis and biological properties of lactones containing an aromatic substituent in the β-position of the lactone ring. The described group of compounds includes halolactones, hydroxylactones, unsaturated lactones...

article

Chiroptical spectroscopic studies for the absolute configuration determination of hexahydrocurcumin and octahydrocurcumin

Andrew R. Puente, Kalyanam Nagabhushanam, Savita Ganjihal, Muhammed Majeed, more

Chirality > 34 > 12 > 1515 - 1525

Hexahydrocurcumin (HHC) and octahydrocurcumin (OHC) were synthesized, and their enantiomers were separated using supercritical fluid chromatography. The absolute configurations (ACs) of HHC and OHC were independently determined using experimental measurements and quantum theoretical predictions of vibrational circular dichroism, electronic circular dichroism, and optical rotatory dispersion. These...

article

Crystal structure, absolute configuration and characteristic temperatures of SmFe₃(BO₃)₄ in the temperature range 11–400 K

Ekaterina S. Smirnova, Olga A. Alekseeva, Alexander P. Dudka, Timofei A. Sorokin, more

Acta Crystallographica Section B > 78 > 3-2 > 546 - 556

The crystal structure of samarium iron borate was analyzed with regard to growth conditions and temperature. The inclusion of about 7% Bi atoms in the crystals grown using the Bi₂Mo₃O₁₂‐based flux was discovered and there were no impurities in the crystals grown using the Li₂WO₄‐based flux. No pronounced structural features associated with Bi inclusion were observed. The different absolute configurations...

article

Enantioselective HPLC analysis of escitalopram oxalate and its impurities using a cellulose‐based chiral stationary phase under normal‐ and green reversed‐phase conditions

Chiara Cantatore, Paola Bertocchi, Daniela De Orsi, Alessia Panusa, more

Journal of Separation Science > 45 > 5 > 1059 - 1066

Normal‐phase and reversed‐phase high‐performance liquid chromatography methods for the separation of the active pharmaceutical ingredient escitalopram from its (R)‐enantiomer impurity have been developed on the cellulose‐based Chiralcel OJ‐H chiral stationary phase. Both methods share two features: they use ethanol as a cosolvent and are able to give a complete enantioseparation without interference...

article

ECD exciton chirality method today: a modern tool for determining absolute configurations

Gennaro Pescitelli

Chirality > 34 > 2 > 333 - 363

The application of the exciton chirality method (ECM) to interpret electronic circular dichroism (ECD) spectra is a well‐established and still popular approach to assign the absolute configuration (AC) of natural products, chiral organic compounds, and organometallic species. The method applies to compounds containing at least two chromophores with electric dipole allowed transitions (e.g., π–π* transitions)...

Publication date

Last year (3)
Last 3 years (24)

Close

Date range setting

Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.

From:

To:
Set your own date range

Content availability

Available (590)
None (32)

Publication type

article (614)
book (8)

INFONA - science communication portal

Search results

A new 3,4-seco-oleanane-type triterpenoid with an unusual enedione moiety from Hypericum ascyron

Bis-spirolabdane diterpenoids from Leonurus japonicus and their anti-platelet aggregative activity

Total synthesis of epicoccamides A and D via olefin cross-metathesis

Novel nardosinane type sesquiterpenoids from Nardostachys chinensis Batal

Anti‐inflammatory Steroids from the South China Sea Sponge Spongia officinalis

Circular Dichroism Sensing: Strategies and Applications

Circular Dichroism Sensing: Strategies and Applications

An Artificial Intelligence Approach for Tackling Conformational Energy Uncertainties in Chiroptical Spectroscopies

Cover Picture: An Artificial Intelligence Approach for Tackling Conformational Energy Uncertainties in Chiroptical Spectroscopies (Angew. Chem. Int. Ed. 38/2023)

Titelbild: An Artificial Intelligence Approach for Tackling Conformational Energy Uncertainties in Chiroptical Spectroscopies (Angew. Chem. 38/2023)

An Artificial Intelligence Approach for Tackling Conformational Energy Uncertainties in Chiroptical Spectroscopies

Absolute Configuration Determination of Chiral API Molecules by MicroED Analysis of Cocrystal Powders Formed Based on Cocrystal Propensity Prediction Calculations**

Structures and absolute configurations of excoecoumarins A and B studied by experimental and theoretical NMR and circular dichroism spectra

Total Synthesis, Absolute Configuration, and Phytotoxic Activity of Foeniculoxin

Propeller, Linear, Cruciform and Stellate Spiro‐bicarbazolium Salts

Otrzymywanie i właściwości biologiczne racemicznych i optycznie czynnych laktonów z pierścieniem aromatycznym w pozycji β

Chiroptical spectroscopic studies for the absolute configuration determination of hexahydrocurcumin and octahydrocurcumin

Crystal structure, absolute configuration and characteristic temperatures of SmFe₃(BO₃)₄ in the temperature range 11–400 K

Enantioselective HPLC analysis of escitalopram oxalate and its impurities using a cellulose‐based chiral stationary phase under normal‐ and green reversed‐phase conditions

ECD exciton chirality method today: a modern tool for determining absolute configurations

Filter options

Publication date

Content availability

Publication type

Publication language

Keywords

Data set

INFONA - science communication portal

Search results

Add recipient

Sending message cancelled

Are you sure you want to cancel sending this message?

Send message

Filter options

Publication date

Date range setting

Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.

Content availability

Publication type

Publication language

Keywords

Data set

Reporting an error / abuse

Sending the report failed

Accessibility options