tetrahydrobenzo[b]pyran derivatives 1 were utilized for the synthesis of several new pyrano[2,3-d]pyrimidine derivatives 2. compound 2 was obtained in the presence of ac2o/h2so4 (as a catalyst) and was confirmed by spectroscopic data such as ir, 1h nmr and 13c nmr. ab initio calculation was carried out to study geometric optimization, thermodynamic parameters, aromaticity and dynamic process of...

Nuclear magnetic resonance (NMR) has been recognized for well over 40 years. Although the first successful in vivo NMR experiments date back to 1946-1948, it was not until the 1970s that the first experiments involving NMR spectroscopyand imagingof living systems were reported in the literature. Since that time the clinical application of NMR has experienced exponential growth. Because of this ...

to determine the non-bonded interaction energies between naphthalene and b12n12 nano ring in different orientations and distances, geometry of molecules with b3lyp method and 6-31g* basis set optimized. also reactivity and stability of naphthalene alone and in the presence b12n12 nano ring checked. then calculated the nbo, nmr, freq, nics and muliken charge of naphthalene atoms alone and in the...

in this work, we have studied binding of clonidine drug (c9h9cl2n3) with zigzag single walled carbonnanotubes (swcnt) (5, 0) by theoretical methods of theory using gaussian 09 software package.binding energies, nmr parameters and homo- lumo gap energy were calculated. results frombinding energies indicate that it is possible thermodynamically to bind clonidine drug to swcnt.the calculated nmr p...

the coupling of tetrazotised 1,8-diaminonaphthalene with 1,3-dicarbonyl compounds [acetylacetone,methylacetoacetate and acetoacetanilide] yielded a new series of tetradentate ligand systems. analytical, ir,1h nmr and mass spectral data indicate that the compounds exist in the intramolecularly hydrogen bondeddihydrazone form. dibasic tetradentate n2o2 coordination of these compounds in their [ml...

the main objective in classification of the nmr spectra of cancerous and healthy tissue , with high number of features is the prerequisites of the minimum number of samples. therefore the use of conventional classifier on this type of the data is not recommended. in the current work, different structures of the artificial neural networks (ann) were tried on classification of different cancerous...

over the past decade, the chemical behavior of flavonoids as antioxidants has become the subject ofintense experimental research. plants represent a main source of natural antioxidants that might serveas leads for the development of novel drugs. malva sylvestris l. known to have various medicinalproperties since several decade ago, were evaluated for their antioxidant compounds ,most of thesebi...

As a complementary analysis tool to conventional high-field nuclear magnetic resonance (NMR), zero- ultralow-field (ZULF) NMR detects magnetization signals in the sub-microtesla regime. Spin-exchange relaxation-free (SERF) atomic magnetometers provide new generation of sensitive detectors for ZULF NMR. Owing features such as low cost, high resolution, and portability, has recently attracted con...