Novel Reactions of Tropylium Salts with Heterocyclic Diamines

Russian Journal of General Chemistry - The reactions of tropylium salts with 2,5-diamino-1,3,4-thiadiazol, 3,5-diamino-1,2,4-thiadiazol, and 2,6-diaminopyridine have given novel products of...     

Heat capacities and thermodynamic functions of new nanosized ferro-chromo-manganites LaM<Subscript>0.5</Subscript><Superscript>II</Superscript>FeCrMnO<Subscript>6.5</Subscript> (M<Superscript>II</Superscript>–Mg,Ca, Sr,Ba)

The heat capacities of nanosized ferro-chromo-manganites LaM_0.5 ^IIFeCrMnO_6.5 (M^II–Mg, Ca, Sr, Ba) are measured via dynamic calorimetry in the temperature range of 298.15–673 K using an IT-S-400 instrument. It is established that the C°_p~f(T) function of LaM_0.5 ^IIFeCrMnO_6.5 (M^II–Mg, Ca, Sr, Ba) has λ-type effects, due probably to phase transitions of the second order. Considering the temperatures of the phase transitions, equations of the heat capacity of ferro-chromo-manganites LaM_0.5 ^IIFeCrMnO_6.5 (M^II–Mg, Ca, Sr, Ba) as a function of temperature are derived on the basis of experimental data. Thermodynamic functions Н°(Т)–Н°(298.15), S°(Т), and Ф ^хх(Т) are calculated in the temperature range of 298.15–675 K.     

Carbenium Ions in Substitution Reactions at the Amino Nitrogen Atom

Tropylium, xanthylium, and tritylium salts characterized by different stabilities differently reacted with biologically active amines. The reactions of tropylium perchlorate and tetrafluoroborate with 4-(cyclohepta-2,4,6-trien-1-yl)aniline was accompanied by hydrolysis of the N-(cyclohepta-2,4,6-trien-1-yl) derivative, the N-xanthenyl derivative underwent dehydrogenation, whereas tritylium perchlorate failed to react with 4-(cyclohepta-2,4,6-trien-1-yl)aniline. The reactions of pyrimidin-2-amine with tropylium, xanthylium, and tritylium salts afforded products of substitution of one hydrogen atom in the amino group with high yields. The N-substituted pyrimidin-2-amine derivatives were stable, and neither their dehydrogenation nor hydrolysis was observed.     

Modification of Monocarboxylic Acid Hydrazides with Tropylium Salts

Russian Journal of Organic Chemistry - Nicotinic, isonicotinic, and furan-2-carboxylic acid hydrazides reacted with 2 equiv of tropylium perchlorate or tetrafluoroborate to give the corresponding...     

Reaction of Thioxanthylium Cation with Pharmacophoric Heterocyclic Amines

Russian Journal of Organic Chemistry - Reactions of thioxanthylium tetrafluoroborate with pharmacophoric heterocyclic amines, pyrimidin-2-amine, 4,6-dimethylpyrimidin-2-amine,...