Reaction of thieno[2,3-d]pyrimidines with mercury salts

The reaction of mercury salts with thieno[2,3-d]pyrimidine derivatives was studied. It was shown that even in nucleophilic solvents the solvatomercuration of thienopyrimidines is accompanied by intramolecular ring closure involving the sulfur atom of the thioureide group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1141–1143, August, 1987.     

Cyclization of some substituted 2-(n-acylthioureido)-3-carbethoxythiophenes

The intramolecular cyclization of 2-(N-acylthioureido)-3-carbethoxy-4,5-R,R'-thiophenes with the formation of potassium salts of 2-thio-4-oxo-5,6-R,R'-3,4-dihydrothieno[2,3-d] pyrimidine was studied, and some of their S-derivatives were obtained.     

Acylation and iodination of 5-(p-R-phenyl)-1,2,4-triazole-3-thiones

The acylation of 5-(p-R-phenyl)-1,2,4-triazole-3-thiones was studied. It was shown that the reaction depends on the nature of the group in the para position of the 5-phenyl substituent. Iodination of the sodium salts of 1,2,4-triazole-3-thiones is accompanied by the formation of disulfides, whereas 1,2,4-triazole-3-thiones that contain an unsaturated substituent with an allylic bond in the 4 position of the ring are iodinated to give condensed thiazolotriazole systems.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 843–846, June, 1984.     

Heterocyclization Reactions of 2-(2-Propynylthio)-4(1H)-quinazolinone Derivatives when Treated with Electrophilic and Nucleophilic Reagents

Reaction of the potassium salt of 2-thioquinazolin-4-one with propargyl halides leads to formation of 2-propargylthioquinazolin-4-one derivatives, which undergo heterocyclization when they are treated with electrophilic or nucleophilic reagents and, depending on the nature of the cyclization agent, leads to formation of tricyclic systems with angular or linear structure.     

Synthesis of 2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]selenophene and some transformations based on it

A new method for the synthesis of 2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]selenophene was developed. The reaction of the latter with allyl isothiocyanate gave 2-(N-allylthioureido)-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]selenophene, which is cyclized to the potassium salt of 3-allyl-4-oxo-2-thio-3,4,5,6,7,8-hexahydrobenzo[b]selenopheno[2,3-d]pyrimidine on treatment with potassium hydroxide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 326–328, March, 1973.     

Synthesis of 2-selenothieno[2,3-d]pyrimidine derivatives

Intramolecular cyclization of 2-(N-acylselenoureido)-3-carbethoxy-4,5,6,7-tetrahydrobenzo[b]thiophenes in alkaline media leads to the formation of the potassium salt (I) of 2-seleno-4-oxo-3,4,5,6,7,8-hexahydrobenzo[b]thieno[2,3-d]pyrimidine, acidification of which yielded the corresponding base in free form. Some pyrimidine compounds containing a selenium atom in the side chain were obtained by reaction of potassium salt I with halo derivatives (ClCH₂CH₂COOCH₃ and ClCH₂CH₂OH).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 753–754, June, 1977.     

Thermal stability of the amorphous system As-Se-I

The effect of adding iodine to the binary systems As-Se on the thermal stability of the ternary glasses thus formed was investigated by DTA and DDTA. The investigated glasses corresponded to different regions of the phase diagram, i.e. they had different contents of As and I and, consequently, contained different types of structural units.In the investigated ternary systems with iodine, the crystallization effect appears at a lower temperature than in the binary glass As₄₀Se₆₀, and the same holds for the temperatures of softening and melting.For both binary and ternary systems, the activation energies of crystallization were determined. The glass As₄₀Se₆₀ exhibited a somewhat higher activation energy, i.e. a somewhat lower tendency to crystallize than the ternary system.The critical cooling rates of the melts for minimum degree of crystallinity were estimated. The obtained values are approximately equal for the binary (As₂Se₃) and ternary (AsSeI) systems.

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Zusammenfassung Mittels DTA und DDTA wurde untersucht, wie die Zugabe von Jod zu dem binären System As-Se die thermische Stabilität der so gebildeten ternären Gläser beeinflußt. Die untersuchten Gläser entsprechen verschiedenen Regionen des Phasendiagrammes, d.h. sie besitzen einen unterschiedlichen As- bzw. I-Gehalt und enthielten unterschiedlich geartete Struktureinheiten.Bei den untersuchten jodhaltigen ternären Systemen tritt der Kristallisationseffekt bei niedrigeren Temperaturen auf als bei den binären Gläsern As₄₀Se₆₀, das gleiche gilt für die Schmelz- als auch für die Erweichungstemperatur.Sowohl bei den binären als auch bei den ternären Systemen wurde die Aktivierungs energie für den Kristallisationsprozeß ermittelt. Das Glas As₄₀Se₆₀ zeigte eine etwas höhere Aktivierungsenergie, d.h. eine etwas geringere Neigung zur Kristallisation als das ternäre System.Für die kritische Abkühlgeschwindigkeit der Schmelzen zum Erreichen eines minimalen Kristallinitätsgrades wurden bei den binären (As₂Se₃) und ternären (AsSeI) Systemen annähernd gleiche Werte bestimmt.

     

Magnetic circular dichroism calculations using the irreducible tensor method

The irreducible tensor method is used to derive simple expressions for the magnetic circular dichroism (Faraday Effect) parameters A/D and C/D for electric dipole allowed and vibronic transitions.