Synthesis of 3-cyano-5-ethoxycarbonyl-4-isobutyl-6-methyl-3,4-dihydropyridine-2(1H)-thione by three-component condensation

Condensation of isovaleraldehyde with cyanothioacetamide and ethyl acetoacetate (or its enamine) gives 3-cyano-5-ethoxycarbonyl-4-isobutyl-6-methyl-3,4-dihydropyridine-2(1H)-thione. This compound was used in the synthesis of substituted 1,4-dihydropyridin-2-yl sulfides. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 166–168, January, 1999.     

Instantaneous Speckle-Modulated Interference Images and Coherent Effects in Optical Microscopy of Thin Layers

Optics and Spectroscopy - We consider the formation of instantaneous speckle-modulated interference images of thin transparent layers in an optical microscope under their illumination of either...     

Synthesis of 4-aryl-6-phenyl-2-thioxo-1,2-dihydropyridine-3-carbonitriles by three-component condensation of aromatic aldehydes with cyanothioacetamide and 4,4,4-trifluoro-1-phenylbutane-1,3-dione

4-Aryl-6-phenyl-2-thioxo-1,2-dihydropyridine-3-carbonitriles were synthesized by three-component condensation of aromatic aldehydes with cyanothioacetamide and 4,4,4-trifluoro-1-phenylbutane-1,3-dione. The reaction involved initial formation of Michael adducts which underwent acyl cleavage.     

Co-Fe/Al2O3 Nanocomposite Catalysts of the Process of CO2 Hydrogenation

Theoretical and Experimental Chemistry - Effective catalysts of CO2 hydrogenation towards methane were obtained by impregnation of aluminum oxide with cobalt and iron nitrates. The catalysts have...     

Vibronic Structures of the Ground and Excited Singlet Electronic States of Dimethylnaphthalenes Cooled in a Supersonic Jet

Abstract

Fluorescence excitation and dispersed fluorescence spectra of jet-cooled naphthalene and 2,6-, 2,7-dimethylnaphthalenes have been measured. The frequencies of optical active vibrations in the ground and first excited singlet states have been determined. The new technique for calculation of planar vibration frequencies of polycyclic benzenoid hydrocarbons in the excited electronic states has been developed. The vibration frequencies in the ground and first excited singlet states of these molecules were calculated using the developed technique and the Ohno's model. The interpretation of vibronic spectral lines based on the comparison of the calculated and experimental data was made. The calculation rms errors for the vibration frequencies in the ground electronic states of the investigated molecules do not exceed 20 cm^?1 and are approximately 1.5 times higher for excited states without additional adjustment of parameters for individual molecules.     

Naphthalene proton sponges as hydride donors: diverse appearances of the tert-amino-effect

It has been shown that the 1-NMe(2) group in the 2-substituted 1,8-bis(dimethylamino)naphthalenes (proton sponges) can intramolecularly donate a hydride ion to an appropriate electron-accepting ortho-substituent such as diarylcarbenium ion, β,β'-dicyanovinyl or methyleneiminium group. This produces the 1-N(+)(Me)=CH(2) functionality and triggers a number of further transformations (tert-amino effect) including peri-cyclization, ortho-cyclization or hydrolytic demethylation. In each particular case, the course of the reaction is determined by the nature of the ortho-substituent and the most potent nucleophile presenting in the reaction mixture. For 2,7-disubstituted 1,8-bis(dimethylamino)naphthalenes, two types of tandem tert-amino effect with the involvement of both peri-NMe(2) groups have been registered. The conclusion was made that proton sponges are generally more active in the tert-amino reactions than the corresponding monodimethylaminoarenes. This is ascribed both to higher electron donor ability of proton sponges and markedly shortened distance between electrophilic C(α)-atom in the ortho-substituent and hydrogen atoms of the nearest NMe(2) group. Most conversions observed proceed in good to high yields and are useful for the preparation of derivatives of benzo[h]quinoline, quino[7,8:7',8']quinoline, 2,3-dihydroperimidine, N,N,N'-trimethyl-1,8-diaminonaphthalene and proton sponge itself.     

Synthesis of new 2-thioxo-1,2,3,4-tetrahydropyridine-3-carboxanilides and their alkylation

2-Thioxo-1,2,3,4-tetrahydropyridine-3-carboxanilides were obtained by the reaction of α,β-unsubstituted ketones with 2-thioxocarbamoylacetanilide and their alkylation was studied. Structure of 3-allyl-4,6-diphenyl-2-thioxo-1,2,3,4-tetrahydropyridine-3-carboxanilide was proved by the X-ray diffraction method.     

Synthesis and Structural Characterization of the First Europium(III) Pyridylphosphine Complex, [Eu(N,N’,N”-2-Py3P)(NO3)3]

The first europium(iii) pyridylphosphine complex, [Eu(N,N’,N”-2-Py₃P)(NO₃)₃] was prepared by the reaction between Eu(NO₃)₃.6H₂O and tris(2-pyridyl)phosphine; its structure was characterized by single-crystal X-ray diffraction.