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.     

Synthesis of 4-Hydroxy- and 4-Amino-2-Methyl-3-(2-Methylindol-3-Yl)methylquinolines and Their 6- and 8-Substituted Derivatives

A method has been developed for the synthesis of substituted 4-hydroxy- and 4-amino-2-methyl-3-(2-methylindol-3-yl)methylquinolines by treating the corresponding 4-hydroxy(chloro)-2-methyl-3-(3-oxobutyl)quinolines with phenylhydrazine hydrochloride. It was found that nucleophilic substitution occurred in the case of the 4-chloroquinolines together with subsequent rearrangement to give the 4-amino derivatives. The thiosemicarbazones of the corresponding 4-hydroxy-2-methyl-3-(3-oxobutyl)quinolines were also obtained.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 554–557, April, 2005.     

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.     

Design of pincer complexes based on (methylsulfanyl)acetic/propionic acid amides with ancillary S‐ and N‐donors as potential catalysts and cytotoxic agents

Pincer complexes featuring readily tunable tridentate ligand frameworks comprise one of the most actively studied classes of organometallic and metal–organic compounds and find extensive use in catalysis, organic synthesis, materials science, and other fields of chemistry and allied disciplines. Currently growing attention is devoted to non‐classical ligand scaffolds, such as functionalized carboxamides, which offer multiple options for directed structural modifications. In this study, the reactions of (methylsulfanyl)acetyl and propanoyl chlorides with 2‐(aminomethyl)pyridine, 2‐(2‐aminoethyl)pyridine, 8‐aminoquinoline and 2‐(diphenylthiophosphoryl)aniline afford a series of new pincer‐type ligands based on functionalized carboxamides. The ligands obtained readily undergo direct cyclopalladation under the action of PdCl₂(NCPh)₂ in dichloromethane at room temperature, resulting in Pd(II) pincer complexes with N,N,S‐ and S,N,S‐donor sets. Importantly, some of the cyclopalladated derivatives can also be produced efficiently under solvent‐free conditions according to the approach recently developed by our group. The complexes obtained have been tested for cytotoxicity against several human cancer cell lines and catalytic activity in the model Suzuki reaction. The results have been compared to those for the related Pd(II) pincer complexes to define the main structure–activity relationships and to outline the most promising structures for further investigations.