Synthesis and some transformations of functionally-substituted coumarins and 2-thioxo-2H-chromenes

A synthesis has been developed for substituted coumarins and 2-thioxo-2H-chromenes and some of the chemical transformations of these compounds were studied.Yerevan State University, 375049 Yerevan, Armenia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 909–912, July, 1996. Original article submitted December 30, 1995; revision submitted April 16, 1996.     

Synthesis and modification of 4-hydroxy-2-methyl-3-(2-chloro-2-propenyl)quinoline

4-Hydroxy-2-methyl-3-(2-chloro-2-propenyl)quinoline was prepared by O-allylation of 4-hydroxy-2-methylquinoline followed by the Claisen rearrangement of the 2-methyl-4-(2-chloro-2-propenyloxy)quinoline obtained. Chemical modifications of 4-hydroxy-2-methyl-3-(2-chloro-2-propenyl)quinoline resulted in the synthesis of 4-amino-2-methyl-3-(2-methyl-3-indolyl)quinoline.     

Phosphorylthioacetamides in the synthesis of annulated quinoxalines

Diethoxyphosphorylthioacetamide in the reaction with 2,3-dichloroquinoxaline acted as a thionating reagent, giving diethoxyphosphorylacetonitrile and 2-chloro-3-[(3-chloro-2-quinoxalinyl)thio]quinoxaline. Reactions of phosphorylthioacetamides with N-methylquinoxalinium iodide in alcohol media in the presence of a base proceeded stereoselectively to afford cis-3-phosphoryl-1,3,3a,4,9,9a-hexahydro-2H-pyrrolo[2,3-b]quinoxaline-2-thiones. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1010–1013, May, 2007.     

The vibrational spectra of complexes of norbornadiene with some group VIII metals

The infrared and Raman spectra of norbornadiene complexes of Pd, Pt, Rh and Fe have been studied. An assignment of the normal modes is given and the ligand vibrations in the complex are compared with those for “free” norbornadiene. The ν(CC) stretching frequency of coordinated norbornadiene is from 1575 cm^?1 to over 1400 cm^?1.The strength of the metal—ligand bond increases in the series Pd < Pt < Rh and for halogen complexes in the series chloride < bromide < iodide. ESCA spectroscopy data obtained are in agreement with these conclusions.     

Synthesis of Substituted 2-Methyl-4-quinolyl Isothiocyanates and 4-Mercaptoquinolines

Synthesis was performed of substituted 2-methyl-4-quinoline thiouronium salts by reaction of 2-methyl-4-chloroquinolines with thiourea. The alkaline hydrolysis of these salts afforded the corresponding 2-methyl-4-quinolyl- isothiocyanates and 2-methyl-4-mercaptoquinolines.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 5, 2005, pp. 783–785.Original Russian Text Copyright © 2005 by Avetisyan, Aleksanyan, Ambartsumyan.     

Synthesis and certain conversions of 3-(3,3-dichloroallyl)-4-hydroxycoumarin

A method has been developed for the synthesis of 3-(3,3-dichloroallyl)-4-hydroxycoumarin and 2-thioxo-3-(3,3-dichloroallyl)-4-hydroxy-2H-chromene, and certain conversions of these compounds have been studied. They undergo acid hydrolysis readily, forming (respectively) 3-(4-hydroxy-3-coumarin)- and 3-(2-thioxo-4-hydroxy-2H-chromene-3)propionic acids; these compounds are converted to the corresponding lactones by the action of acetic anhydride.Erevan State University, Erevan 375049. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 48–51, January, 1997.     

The vibrational spectra of molecular crystals of ferrocene,ruthenocene, osmocene and nickelocene

Studies are presented of the infrared spectra (3200–400 cm^?1) of monocrystal films of Fe (C₅H₅)₂ Ru(C₅H₅)₂, Os(C₅H₅)₂ using polarized radiation, and of the laser-Raman spectra of solid samples of these compounds in the temperature range +20° to ?190°C. The samples were prepared by slow cooling of the melts. The infrared spectra of solid films of Ni(C₅H₅)₂ made by deposition on a cold window, were also recorded. Assignments of the fundamental vibrational frequencies of these molecules are given. The fundamental modes of vibrations which are forbidden by symmetry appear in the spectra of the solid state. The vibrations of species E_1u and E_2u showed definite site group splitting. At the point of phase transition in the IR spectrum of Fe(C₅H₅)₂ factor-group splitting to give 3–4 components for bands of species A_1u and A_2u and 6–8 components for bands of species e_1u and E_2u was observed. Factor-group analysis is more consistent with C₁ site symmetry of the low-temperature phase of the crystal of ferrocene than C_i, as was proposed earlier.     

Synthesis and Complexing Properties of Phosphorus-Substituted Pyridine-2-Carboxylic Acid Anilides

Abstract

Novel phosphorus-containing ligands have been synthesized by the condensation of 2-(thio)phosphorylated anilines with 2,6-dichloro- and 4-chloropyridine-2-carbonyl chlorides in the presence of Et₃N and unsubstituted pyridine-2-carboxylic acid using P(OPh)₃ as a coupling agent. The compounds derived readily form complexes with a range of transition metals (M=Re(I), Pd(II), and Cu(II)), serving as bi- or tridentate monoanionic ligands. The composition and structure of the resulting metallocycles depend both on the presence/amount of the Cl atoms in the pyridine ring and on the nature of the donor atom X in the P=X moiety. The novel compounds were characterized by multinuclear NMR and IR spectroscopy as well as X-ray crystallography.     

Specifics of the formation of alloys and their hydrides in Ti-Zr-H system

Studies of the combustion processes in the Ti-H, Zr-H, and Ti-Zr-H systems made it possible to develop a principally new method for producing refractory metal alloys through the compaction of a titanium hydride-zirconium hydride powder mixture followed by dehydrogenation. The procedure is briefly described. Experimental data on the formation of titanium-zirconium alloys with different structures, including an ω-phase alloy obtained at atmospheric pressure, are discussed. The experimental results clearly show that the structure of the alloy depends on the composition of the initial charge and the hydrogen content in the hydrides used. The interaction of the alloys obtained with hydrogen under conditions of self-propagating high-temperature synthesis yielded Ti_0.9Zr_0.1H_1.87 (Ti₉ZrH_18.7), Ti_0.67Zr_0.33H_1.81 (Ti₂ZrH_5.42), Ti_0.5Zr_0.5H_1.37 (TiZrH_2.74), and Ti_0.3Zr_0.7H_1.96 (TiZr_2.3H_6.53) hydrides with face-centered cubic (fcc) and body-centered tetragonal (bct) structures. The removal of hydrogen from these hydrides (by annealing in vacuum at 700–1050°C) results in the recovery of the initial α and ω phases.