نتایج جستجو برای: nmr and el_tofms
تعداد نتایج: 16839182 فیلتر نتایج به سال:
objective during the last three decades sesquiterpenoid lactones have emerged as one of the largest groups of plant products with over 3000 naturally occurring substances known. the genus artemisia characteristically contains this biologically active type of secondary metabolites. with respect to increasing interest in the cytotoxic, antibiotic, phototoxic and antineoplastic activities of sesqu...
The Dopamine has been studied theoretically at the B3LYP/6-31G* level were performed in gasphase. We calculated physical parameters like atomic charges, energy (=>), asymmetry parameter(?), chemical shift @iso, dipole moment and isotropic NMR determinant and in this work we usedGaussian 03 at NMR and calculation by using B3LYP methods with 6-31G* basis set.
phytochemical investigation of the dichloromethane extract of the dried roots of ferula badrakema resulted in the identification of one new and six known compounds. known compounds were sesquiterpene coumarins: mogoltacin, feselol, badrakemin acetate, ferocaulidin, conferone and conferol acetate. the new compound was a sesquiterpene, named badrakemonin. the structures of these compounds were el...
an efficient synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles by one-step condensation of an aldehyde, benzil, ammonium acetate and primary amine in the presence of nanocrystalline magnesium aluminate under microwave irradiation is described. the advantages of this catalyst are including simple work-up, low cost and reusability. compared with conventional methods, the ...
some oxime ether derivatives of α-ionone (4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one) have been synthesized. reaction of 4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-ketoxime with various chloro and fluoro aromatic and hetero aromatic compounds gave the corresponding oxime ether derivatives via aromatic nucleophilic substitution (snar). the structures of these compounds were elucida...
The 1H and natural-abundance 13C-NMR spectra of 1-thiacyclooctan-3-one (1) have been measured from 25 to -100°C. Coalescence is observed in the 1H-NMR spectra of (1) at about -80°C, and attributed to ring inversion in a boat-chair conformation, which is the predominant conformation of (1). The free energy of activation (DG¹</s...
conformational properties of n-aryl-1-azacyclooctan-5- ones with a p-methyl, m-methyl, and p-methoxy group as a substituent have been studied by 1h-nmr, 13c-nmr and ir spectroscopies. transannular interaction of the two functional groups have been examined from the ring inversion barriers and the carbonyl vibrational frequencies with reference to the corresponding data of the respective monofun...
Body's iterative force-field computer program has been used to calculate strain energies in cyclooctanone (I). 348 MHZ 1H NMR spectra of (I) have been investigated over the temperature range of 25° to -160°C. Two conformation processes affect the 1H NMR spectrum of (I). Iterative force-field calculations on the conformations and conformational interconversion paths of ...
Phytochemical investigation of the dichloromethane extract of the dried roots of Ferula badrakema resulted in the identification of one new and six known compounds. Known compounds were sesquiterpene coumarins: mogoltacin, feselol, badrakemin acetate, ferocaulidin, conferone and conferol acetate. The new compound was a sesquiterpene, named badrakemonin. The structures of these compounds were el...
An efficient synthesis of vinylphosphonates is described. This involves the reaction of alkyl cyanoformates and dialkyl acetylendicarboxylates in the presence of trialkyl phosphites. The 1H, 13C NMR, and 31P NMR spectra of vinylphosphonates having different substitution are consistent with the presence of two geometrical isomers.
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید