Synthesis of new arylidene derivatives of 3-aminorhodanine

The synthesis of new arylidene derivatives of 3 -aminorhodanine has been effected. It has been established that the condensation of 3-aminorhodanine with aldehydes in an alcoholic medium gives 3′-arylidene derivatives. Similar reactions in an ammoniacal medium lead to 5-derivatives of 3-aminorhodanine. 3′, 5-Diarylidene derivatives can be obtained by condensing 3′-aminorhodanine with an excess of an aldehyde in glacial acetic acid, except for the salicylidene and 9-anthrylidene derivatives, the synthesis of which can be carried out only in two stages.     

UV absorption spectra of 3-aminorhodanine derivatives

3-Aminorhodanine condenses readily with isothiocyanates to form unsymmetrical thioureas of the rhodanine series. The UV spectra of arylidene derivatives of 3-aminorhodanine consist of four bands: a short-wave band with a maximum up to 242 nm, a “thioamide” band with a maximum at 264–290 nm, a “dithiocarbonate” band with maxima at 290–370 nm, and a long-wavelength K band with maxima at 310–520 nm. The K absorption band is the most characteristic band for the arylidene derivatives of 3-aminorhodanine, and the maxima for 3′,5-diarylidene derivatives are generally shifted to the short-wave region, while the maxima for the 5-monoarylidene derivatives are usually shifted to the long-wave region.     

Synthesis of new arylidene derivatives of 3-aminorhodanine

The synthesis of new arylidene derivatives of 3 -aminorhodanine has been effected. It has been established that the condensation of 3-aminorhodanine with aldehydes in an alcoholic medium gives 3-arylidene derivatives. Similar reactions in an ammoniacal medium lead to 5-derivatives of 3-aminorhodanine. 3, 5-Diarylidene derivatives can be obtained by condensing 3-aminorhodanine with an excess of an aldehyde in glacial acetic acid, except for the salicylidene and 9-anthrylidene derivatives, the synthesis of which can be carried out only in two stages.     

Derivatives of 2-benzazepine-1,3-dione

The reactions of the di(acid chloride) of 2-carboxy-3,4-dimethoxyphenylthiopyruvic acid with 1-aminoadamantane and with thiosemicarbazide take place with the closure of a seven-membered ring and the formation of 1,2-dihydro-(3H)-2-benzazepine-1,3-dione. On reaction with monochloroacetic acid, 4-mercapto-8, 9-dimethoxy-2-(N-thioureido)-1, 2-dihydro-(3H)-2-benzazepine-3-dione is converted into a derivative of thiazolidine-2,4-dione 2-hydrazone, which readily takes part in condensation reactions with oxo compounds forming 5-ylidene derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 29–32, January, 1984.     

Mn site substitution of La0.67Ca0.33MnO3 with closed shell ions: Effect on magnetic transition temperature

Mn site is substituted with closed shell ions (Al, Ga, Ti, Zr and a certain combination of Zr and Al) and also with Fe and Ru ions carrying the magnetic moment (S=5/2 and 2 respectively) at a fixed concentration of 5 at %. Substitution did not change either the crystal symmetry or the oxygen stoichiometry. All substituents were found to suppress both the metal-insulator and ferromagnetic transition temperatures (T _p(ρ) and T _C, respectively) to varied extents. Two main contributions identified for the suppression are the lattice disorder arising due to difference in the ionic radii between the substituent (r _M) and the Mn³⁺ ion (r _Mn ³⁺) and in the case of the substituents carrying a magnetic moment, the type of magnetic coupling between the substituent and that of the neighboring Mn ion.     

The synthesis of rhodanines with possible antimetabolic activity

Eighteen new derivatives of rhodanine were obtained by the reaction of 3--carboxyethylrhodanine with various oxo-compounds. The condensation proceeded fairly readily in glacial acetic acid with enanthaldehyde, acetal, diacetyl, pyruvic acid, furfural, anthraquinone, -chloroanthraquinone, isatin, 5-bromoisatin, acenaphthenequinone, isobutyraldehyde, cyclopentanone, and cyclohexanone. The condensations with acetone, ethyl methyl ketone, acetoacetic ester, acetophenone, and 2-acetylnaphthalene were carried out by heating in ammoniacal solution.For part II see [1].