Design of fused systems based on σH-adducts of 6-nitro-1,2,4-triazolo[1,5-a]pyrimidine with π-excessive heteroaromatic compounds

Russian Chemical Bulletin - A new method was developed for the construction of tetra- and pentacyclic fused systems based on σH-adducts of 6-nitro-1,2,4-triazolo[1,5-a]pyrimidine with...     

Fluorine-containing heterocycles: XIX. Synthesis of fluorine-containing quinazolin-4-ones from 3,1-benzoxazin-4-ones

Reactions of fluorine-containing 3,1-benzoxazin-4-ones with ammonium acetate, hydrazine, and heteroaromatic amines gave new 3H-, 3-amino-, and 3-hetarylquinazolin-4-ones, respectively. Differences in the conditions of formation of benzoxazinones from anthranilic acids with different fluorination patterns and in the reactions of fluorinated 3,1-benzoxazinones with nitrogen-centered nucleophiles were revealed.     

Fluorine-containing heterocycles: XVIII. Monofluoro derivatives of quinazolines and 1,3-benzothiazin-4-ones

5- and 7-Fluoro-substituted quinazolines and 1,3-benzothiazin-4-ones were synthesized starting from 2-amino-6-fluorobenzonitrile and mono- and difluoro-substituted benzoic acid derivatives. The reactivities of di- and tetrafluoro-substituted benzoyl chlorides and benzoyl isothiocyanates in cyclocondensations leading to fluorinated quinazolines and 1,3-benzothiazines were compared.     

Unusual magnetic behavior of the new supramolecular ensemble [Ni2L4]2·[NiCl2(LH)2(MeCN)2]·4MeCN (LH is 2-mercaptobenzimidazole)

The diamagnetic dinuclear complex Ni₂L₄ was synthesized by the reaction of NiCl₂·6H₂O with 2-mercaptobenzimidazole (LH) in ethanol in the presence of Et₃N. The solid-state reaction (reagent ratio Ni: LH = 1: 2) followed by recrystallization of the reaction product from a MeCN-THF mixture afforded crystals of the associate [Ni₂L₄]₂·[NiCl₂(LH)₂(MeCN)₂] containing four acetonitrile solvate molecules. Crystals of 2·4MeCN exhibit ferromagnetic properties at helium temperatures. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2101–2105, December, 2006.     

Fluorocontaining Heterocycles: IX. Derivatives of Imidazo[2,1-b][1,3]benzothiazine

The heating of derivatives of benzimidazole-2-thione and imidazolidine-2-thione with tetra(penta)fluorobenzoyl chlorides in toluene or pyridine gave rise to fluorocontaining derivatives of imidazo[2,1-b][1,3]benzothiazine. The latter were studied in reactions of nucleophilic substitution of fluorine for amino groups.     

Mechanism of nucleophilic substitution of hydrogen in azines IV. Role of one-electron transfer in reactions with arylamines

A satisfactory correlation between the polarographic reduction potentials and the calculated energies of the lower vacant molecular orbitals was found for a number of N-methylazinium cations. The result of the aza effect and the benzoannelation effect is a shift of the reduction potentials to the positive region by 0.2–0.5 and 0.2–0.7 V, respectively. Electron transfer from N,N,N,N-tetramethyl-p-phenylenediamine to the most electrophilic cations was recorded. The possibility of the occurrence of reactions involving aminoarylation of the acridinium cation via a one-electron mechanism was demonstrated electrochemically and by model reactions.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 690–694, May, 1977.     

Reactions of N-alkylazinium cations. 3. Quaternary pteridinium salts. Synthesis,structure, and reactions with simple nucleophiles

4-Morpholinopteridine reacts with triethyloxonium tetra-fluoroborate to give two types of isomeric quaternary salts, viz., 1-ethyl- and 8-ethyl-4-morpholinopteridinium tetrafluoroborates. The structures of the pteridinium cations were proved by the ¹H and ¹³C NMR spectra and also by chemical transformations in reactions with simple nucleophiles.See [1] for communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1257–1264, September, 1985.     

Oxidative Cyclization of Lithium 4-Ethoxy-1,1,1-trifluoro-4-oxobut-2-en-2-olate

Russian Journal of Organic Chemistry - Diethyl 2,5-dihydroxy-2,5-bis(trifluoromethyl)tetrahydrofuran-3,4-dicarboxylate has been synthesized for the first time by reaction of lithium...