A procedure based on multiple quantum two-dimensional nuclear magnetic resonance spectroscopy is described for generation of 1H--15N chemical shift correlation maps. The method is used to obtain 15N chemical shifts for the exchangeable imino protons in 1H--15N units of site-specifically labeled Escherichia coli tRNAMetf in water. The high sensitivity and excellent chemical shift dispersion of t...

The photolysis at 222 nm of 5-methyltetrazole isolated in a cryogenic argon matrix leads to formation of methyl nitrile imine as primary product. Subsequent irradiation at 328 nm induces transformation of the nitrile imine into 4π-electron three-membered-ring 3-methyl-1H-diazirine, which photorearranges to give methyl carbodiimide. These products were characterized by IR spectroscopy and theore...

The single enantiomer (1S,2S)-2-benzyl-2,3-dihydro-2-(1H-inden-2-yl)-1H-inden-1-ol (2), has recently been synthesized and isolated from its corresponding diastereoisomer (1). The molecular and crystal structures of this novel compound have been fully analyzed. The relative and absolute configurations have been determined by using a combination of analytical tools including X-ray crystallography...

Chemical examination of the Taiwanese soft coral Sinularia flexibilis led to the isolation of five cembrane-based diterpenoids 1-5, including two new metabolites, 11-acetylsinuflexolide (1) and 11-acetyldihydrosinuflexolide (2). The structures of the new metabolites were determined based on extensive spectroscopic analysis, particularly mass spectrometry and 2D NMR (1H-1H COSY, HMQC, HMBC, and...

Three new iridoid glucosides, 10-O-[(E)-cinnamoyl]-geniposidic acid, 10-O-[(E)-p-coumaroyl]-geniposidic acid, 10-O-[(E)-caffeoyl]-geniposidic acid and the known iridoid glucoside, 2'-O-[(E)-cinnamoyl]-mussaenosidic acid have been isolated from Avicennia marina. The structures were determined primarily by NMR spectroscopy. The assignment of NMR signals was performed by means of 1H-1H COSY, HMQC ...

Superhydrophobic surfaces were fabricated by the complex coating of silica nanoparticles with functional groups onto cotton textiles to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane or their combination. The wettability and morphology of the as-fabricated surfaces were investigated by contact angle measuremen...

Proton nuclear magnetic resonance (1H NMR) spectroscopy is a noninvasive technique that can provide information on a wide range of metabolites. Marked abnormalities of 1H NMR brain spectra have been reported in patients with neurological disorders, but their neurochemical implications may be difficult to appreciate because NMR data are obtained from heterogeneous tissue regions composed of seve...

Extremely accurate and precise quantitative NMR was demonstrated using the new qNMR tools in VnmrJ 3.1 software and calibration with an external standard. Periodic calibration can deliver accuracy as high as 99.9 % and precision as good as 0.59%, while performing calibration with each study can result in accuracy and precision as high as 100% and 0.35%, respectively.

A convenient, simple and green process for the synthesis of 2,4,5-triaryl-1H-imidazole and 1,2,4,5-tetraaryl-1H-imidazole derivatives using snail shell, which is abundant in Morocco, as a catalyst in ethanol at 40 °C has been developed. Additionally, short reaction times, excellent yields, simple procedure and relative non-toxicity of the catalyst are other noteworthy advantages and make this m...