Synthesis and structure of substituted 2-amino-3-arylindoles

The corresponding 2-amino-3-arylindole hydrochlorides were obtained by the reaction of substituted arylacetic acid arylhydrazides with phosphorus oxychloride (the Kost reaction). The effect of substituents in the aryl rings on the rearrangement was examined qualitatively. The IR, PMR, and UV spectra of the compounds obtained are discussed in relationship with the peculiarities of their structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1075–1080, August, 1985.     

Synthesis of Nonracemic Tetrazole GABA Analogs

Russian Journal of Organic Chemistry - Nonracemic 3-substituted 4-(1H-tetrazol-1-yl)butanoic acids, analogs of the neurotropic drugs phenibut, tolibut, and baclofen, were synthesized by a...     

Transformations of 5-(2-arylethynyl)-2-methyl-2H-tetrazoles under superelectrophilic activation

Reaction of 5-arylethynyl-2-methyl-2H-tetrazoles (acetylene tetrazoles) with arenes under the action of Brønsted superacid CF₃SO₃H or acidic zeolite HUSY CBV-720 gives rise to E-/Z-5-(2,2-diarylethenyl)-2-methyl-2H-tetrazoles, as products of hydroarylation of acetylene bond, in yields up to 98% with predominant formation of E-isomers. Cationic intermediates of these reactions have been studied theoretically by DFT calculations. Addition of CF₃SO₃H to the triple bond of acetylene tetrazoles leads to the corresponding E-/Z-vinyl triflates in high yields. Hydration of triple bond in these tetrazoles in H₂SO₄ results in the formation of 5-(2-aryl-2-oxoethyl)-2-methyl-2H-tetrazoles. Tandem hydroarylation-ionic hydrogenation of acetylene tetrazoles in the systems acid(CF₃SO₃H or AlCl₃)-arene-cyclohexane affords 5-(2,2-diarylethyl)-2-methyl-2H-tetrazoles.     

A Molecular Dynamics Study of Nickel Crystallization at Strong Supercoolings

The homogeneous crystallization of liquid nickel models containing 2048 particles in the basic cube was studied by molecular dynamics. The potential of the embedded atom method was used. The models were constructed under zero pressure or constant volume conditions. The state of the structure was evaluated from the number of atoms with the coordination number 12. The concentration of such atoms in the stable and metastable liquids increased as the temperature decreased. At the selected potential of the embedded atom model, the equilibrium crystallization temperature at zero pressure was 1415 K. The existence of the lower boundary of liquid nickel supercooling was established. The liquid crystallized under isothermal conditions by the cluster mechanism with the formation of a predominantly closely packed structure below 850 K at zero pressure and below 1075 K at a constant volume (6.588 cm³/mol). The mechanism of nucleation was different from that accepted in classic nucleation theory. Nucleation was accompanied by an increase in the number of atoms with the coordination number 12, the formation of bound groups (12-clusters) from these atoms, and the growth of these groups, as with the crystallization of rubidium under strong supercooling conditions and coagulation of impurities from supersaturated solutions. At the initial stage, bound groups had a very loose structure and contained a large number of atoms with coordination numbers other than 12; the linear size of the largest group rapidly approximated the basic cube size. These atoms played a leading role in crystallization and activated the transfer of atoms in bound groups having different coordination numbers into the coordination state corresponding to a closely packed lattice. An important role in the formation of 12-clusters of the threshold (critical) size played cluster size fluctuations, which were especially strong close to the lower boundary of liquid supercooling.