The potential of tobacco waste as a viable source of medicinally important flavonoids like rutin has been investigated. Three flavonoids, apigenin, quercetin and rutin, have been isolated from waste tobacco leaves, and their identities have been confirmed by UV-visible, 1H-NMR and 13C-NMR spectroscopy. By using analytical HPLC, the amount of rutin present in the tobacco leaves, before and after...

An efficient protocol for the synthesis of 3,4-dihydropyrimidin-2-(1H)-one/thione derivatives via multi-component coupling reaction of aromatic aldehydes, β-ketoester and urea or thiourea under solvent-free conditions using Silica Supported Barium Chloride as a catalyst is described. All prepared compounds with melting points, IR,1H NMR and 13C NMR were identified. High yields, mild conditi...

A new series of N-[2-(1H-1,2,3-benzotriazol-1-yl)ethyl]-4-(substitutedphenyl)-3-chloro-2-oxo-1-iminoazetidine, compounds 4(a-j) were synthesized. The structures of all the synthesized compounds were confirmed by chemical and spectral analyses such as IR, 1H NMR, 13C NMR and FAB-Mass. The compounds 4(a-j) were screened for their antibacterial, antifungal and antitubercular activities and gave ac...

A detailed 13C NMR study of thiostrepton and two series of thiopeptin components is consistent with their proposed structures and allows many unequivocal assignments to be made.

We determine the decay rate constants of zero-, double- and single-quantum coherence for 13C spin pairs in magic-angle-spinning solid-state NMR. The double-quantum coherence is excited by a C7 pulse sequence and converted into zero-quantum coherence by a frequency-selective pair of pi/2 pulses. The zero-quantum coherence is reconverted into observable magnetization by a second pair of pi/2 puls...

A simple method for obtaining 1H–13C HETCOR solid-state NMR spectra reflecting only mediumand long-range 1H–13C correlation peaks is presented. By dephasing the magnetization of protons directly bonded to a 13C nucleus, the short-range correlation peaks, which contain limited structural information, can be cleanly suppressed without reducing the long-range cross peaks significantly. The resulti...

Silica is commonly modified with bifunctional phosphines like PPh2CH2CH2Si(OEt)3 prior to immobilization of catalysts. Here, besides PPh2(CH2)3Si(OEt)3, ligands that are more stable toward oxidation, namely PPh2(C6H4)Si(OEt)3, PPh2(C6H4)SiMe2(OEt), and PPh2(CH2)4OH, are applied. The diand tricarbonylnickel complexes of these ligands are synthesized, characterized by 61Ni, 31P, 13C, and 1H NMR a...

Several problems limit quantification of gluconeogenesis. We applied in vitro 2H-nuclear magnetic resonance (NMR) spectroscopy to simultaneously measure 2H in all glucose carbons for direct assessment of gluconeogenesis. This method was compared with 2H measurement in carbons 5 and 2 using gas chromatography-mass spectrometry (hexamethylenetetramine [HMT]) and with in vivo 13C magnetic resonanc...

The metabolic mechanism of hepatic glucose overproduction was investigated in 3,3'-5-triiodo-l-thyronine (T3)-treated rats and Zucker diabetic fatty (ZDF) rats (fa/fa) after a 24-h fast. 2H2O and [U-13C3]propionate were administered intraperitoneally, and [3,4-13C2]glucose was administered as a primed infusion for 90 min under ketamine-xylazine anesthesia. 13C NMR analysis of monoacetone glucos...

Recoverin, a recently discovered member of the EF-hand protein superfamily, serves as a Ca2+ sensor in vision. A myristoyl or related N-acyl group covalently attached to the amino terminus of recoverin enables it to translocate to retinal disc membranes when the Ca2+ level is elevated. Two-dimensional 1H-13C shift correlation NMR spectra of recoverin containing a 13C-labeled myristoyl group wer...