a a s b i l p ( b b onformation of solid proteins that utilizes selective and extensive C labeling in conjunction with two-dimensional magic-anglepinning NMR. The selective C labeling approach aims to reduce ine broadening and other multispin complications encountered in olid-state NMR of uniformly labeled proteins while still enhancng the sensitivity of NMR spectra. It is achieved by using spe...

ethanolic crude extract of i. imbricata lindl. (iridaceae) was subjected to column chromatography on silica gel with varying portions of meoh: chcl3. nigicin (irisolone) was isolated and its identification carried out by ir, uv, ms, 1-d and 2-d nmr spectroscopy.

Elucidation of high-resolution protein structures by NMR spectroscopy requires a large number of distance constraints that are derived from nuclear Overhauser effects between protons (NOEs). Due to the high level of spectral overlap encountered in 2D NMR spectra of proteins, the measurement of high quality distance constraints requires higher dimensional NMR experiments. Although four-dimension...

Amphiphilic calix[4]resorcinarenes are a class of macrocyclic compounds with broad potential utility including nanomedicine. Here the synthesis new carboxybetaine and ester calix[4]resorcinarene bearing 4-(dodecyloxy)phenyl groups on lower rim is presented. The were characterized by 1H-NMR, 13C-NMR, 2D NMR, IR, ESI elemental analysis. critical association concentration values 1.00 × 10−5 1.18 m...

Traditional nuclear magnetic resonance (NMR) spectroscopy relies on the versatile chemical information conveyed by spectra. To complement conventional NMR, Laplace NMR explores diffusion and relaxation phenomena to reveal details on molecular motions. Under a broad concept of ultrafast multidimensional Laplace NMR, here we introduce an ultrafast diffusion-relaxation correlation experiment enhan...

Most of polypeptides containing α,β-dehydroamino acids have important biological activity, so exploration of synthetic method has practical significance. In this paper, dipeptides were prepared from l-threonine by protecting of c-terminal allyl acetate, and condensing reaction with a series of N-Boc amino acid. Then, treatment of dipeptides obtained with DMAP, (Boc)2O and tetramethylguanidine i...

there are many efforts for identification of natural compounds from dietary or medicinal plants. young roots and aerial parts of a. persicus have been used as food additive or salad vegetable in some parts of iran. in this study, different fractions of the root extract of a. persicus were subjected for isolation and purification of secondary metabolites. the methanol extract of the roots was fr...

The stem bark of Phoebe grandis afforded one new oxoproaporphine; (-)-grandine A (1), along with six known isoquinoline alkaloids: (-)-8,9-dihydrolinearisine (2), boldine, norboldine, lauformine, scortechiniine A and scortechiniine B. In addition to that of the new compound, complete 1H- and 13C-NMR data of the tetrahydroproaporphine (-)-8,9-dihydrolinearisine (2) is also reported. The alkaloid...

An amino acid, 3S-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, was isolated for the first time from the leaves of Cichorium endivia. The complete assignment of its (1)H and (13)C NMR spectroscopic data was carried out also for the first time based on extensive 1D and 2D NMR experiments. Cytotoxicity of this isolated compound against HCT-8 and HepG2 human cancer cell lines was evaluated for...