Synthesis,structure, and properties of tert-butyl perfluorobiphenyl nitroxide

Russian Chemical Bulletin - The reaction of perfluorobiphenyl with tert-butylamine in an autoclave affords the aminodefluorination product,...     

Crystal Structure of the Azoxy Compound Formed by Photochemical Transformation of Niphedipine

The crystal structure of 2,2'-bis[2,6-dimethyl-3,5-di(methoxycarbonyl)pyridinyl-4]azoxybenzene has been determined; the compound is formed as the major product of photodegradation of niphedipine subjected to prolonged exposure of its ethanolic solution to daylight and artificial illumination. It is established that in crystal, the above azoxy derivative has a trans configuration.     

Synthesis and analgesic activity of 1,3,5-trisubstituted pyrazoles containing a diterpenoid moiety

Conjugates of terpenoids with 1,3,5-trisubstituted pyrazoles were synthesized by the cross-coupling of methyl 16-(2-chloro-2-oxoacetyl)labdatrienoate with terminal arylacetylenes via the Castro—Stephens reaction and heterocyclization of arylalkyne-1,2-diones with arylhydr-azines. The structure of one reaction product was established by X-ray diffraction. The conditions for the formation of furanolabdanoid arylalkyne-1,2-diones were found. The newly synthesized pyrazoles exhibit analgesic activity in a model of chemical irritation.

     

Stable vinylnitroxyl radicals, pyrroline derivatives

The first representatives of stable vinyl nitroxides,viz., radicals of the pyrroline series, were synthesized. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 103–111, January, 2000.     

Molecular and crystal structure of polycyclic nitramines

An X-ray structural investigation has been carried out for four polycyclic nitramines with an isowurtzitane structure. These compounds are high-density, high-energy materials: 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diaza-tetracyclo(5.5.0.0^3,11.0^5,9)dodecane (4), 4,8,10,12-tetranitro-2,6-dioxa-4,8,10,12-tetrazatetracyclo (5.5.0.0^3,11.0^5,9)dodecane (5), and 4,6,10,12-tetranitro-2,8-dioxa-4,6,10,12-tetrazatetracyclo(5.5.0.0^3,11.0^5,9)-dodecane (6). Nitramine 5 crystallizes as triclinic (form α, d_calc = 1.966 g/cm³) and trigonal (form β, d_calc = 2.014 g/cm³) modifications. All amine nitrogen atoms have a nonplanar structure; the mean sum of bond angles of the six-membered cycles is 345.2°, and the corresponding mean value for the five-membered cycles is 337.6°. Other features of their intramolecular structure are also discussed.     

Crystal Structure of 6-Chloro-4-nitro-2-phenylpyrimidine

The crystal structures of 6-chloro-4-nitro-2-phenylpyrimidine and 6-chloro-2-phenylpyrimidine have been determined using X-ray diffraction. The effect of the nitro group and the endocyclic nitrogen atoms on the geometric parameters of the 2- and 4-nitropyrimidine molecules, and also related -nitroazines are compared.     

Reactions of N,N-(dialkyl)arylthioacetamides with dialkyl acetylenedicarboxylates

2-(Alkoxycarbonylmethylidene)-4-aryl-5-(dialkylamino)thiophen-3(2H)-ones were synthesized by condensation of N,N-(dialkyl)arylthioacetamides with dialkyl acetylenedicarboxylates. Intermediate substituted vinylic sulfides were isolated. When heated or in the presence of an acid or a base, they undergo cyclization into thiophenes.     

Reaction of 2-Alkoxypropenals with α-Hydroxyamino Oximes and 1,2-Bis(hydroxyamino)cyclohexane

Reactions of 2-alkoxypropenals with α-hydroxyamino oximes in neutral medium involve the aldehyde group of the former to afford both acyclic and cyclic azomethine oxides: N-(2-hydroxyiminoalkyl)-N-(2-alkoxy-2-propenylidene)amine oxides and 1-hydroxy-2,5-dihydroimidazole 3-oxides. The state of tautomeric equilibrium between the cyclic and acyclic products depends on the solvent nature and temperature. The reaction in acidic aqueous medium is accompanied by hydrolysis of the vinyl ether moiety in 2-alkoxy-propenals with formation of 2-oxopropionaldehyde which reacts with α-hydroxyamino oxime at the hydroxy-amino group to give substituted pyrazine 1,4-dioxides. The reaction of 2-alkoxypropenals with 1,2-bis-(hydroxyamino)cyclohexane leads to formation of 2-(1-alkoxyvinyl)-1,3-dihydroxyperhydrobenzimidazoles. The structure of the products was proved by IR, UV, and ¹H and ¹³C NMR spectroscopy and X-ray analysis.