First example of the formation of bipolar spiro σ-complexes from 6-bromo-5,7-dinitrobenzo[e]-1,2,3,4-tetrazine 1,3-di-N-oxide

The reactions of 3,5,7-trimethyltropolone and 2-(N-benzylamino)tropone with 6-bromo-5,7-dinitrobenzo[e]-1,2,3,4-tetrazine 1,3-di-N-oxide afforded novel bipolar spiro -complexes. The kinetic and activation parameters of the R,S-enantiotopomerization of a chiral spiro -complex of 2-(N-benzylamino)tropone were determined using dynamic ¹H NMR spectroscopy.     

Nucleophilic substitution in benzo-1,2,3,4-tetrazine 1,3-dioxides

Nucleophilic substitution in nitro- and bromobenzo-1,2,3,4-tetrazine 1,3-dioxides (BTDOs) was studied. In most cases, the bromo and nitro groups are replaced by methylamino, dimethylamino, azido, and methoxy groups without opening of the tetrazine ring. It was illustrated with the reactions of dibromo-BTDOs with sodium methoxide that the reactivity of positions 5 to 8 in their benzene ring as regards nucleophilic substitution changes in the following order: 6 > 8 > 7 > 5. The structures of the BTDOs obtained were confirmed by ¹H, ¹³C, and ¹⁴N NMR data.     

Novel reaction of 1-aryl-2-bromodiazene 1-oxides with olefins. Synthesis of 1-aryl-2-(2-bromoalkyl)diazene 1-oxides

The addition of 1-aryl-2-bromodiazene 1-oxides to olefins yields 1-aryl-2-(2-bromoalkyl)diazene 1-oxides (4). A radical mechanism of the reaction has been suggested. Compounds4 decompose to give bromohydrazones of formaldehyde and aldehydes. The structural factors that affect the rate of this process are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 917–923, May, 1995.The work was carried out in the Scientific Educational Center of the Institute of Organic Chemistry of the RAS with financial support of the Russian Foundation for Basic Research (Project No. 93-03-18461).     

Synthesis of first nonannulated 1,2,3,4-tetrazine 1,3-dioxides

Thermolysis of o-diazidobenzotetrazine 1,3-dioxides was accompanied by cleavage of the C-C bond of the benzene ring to give nonannulated 1,2,3,4-tetrazine 1,3-dioxides. The structures of these first representatives of nonfused 1,2,3,4-tetrazines were confirmed by ¹³C and ¹⁴N NMR spectroscopy. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1589–1594, September, 2006.     

Synthesis of new titanatranes containing organic substituents in the atrane fragment

Titanatrane CpTi(OCH(CH₃)CH₂)₃N (3) was prepared by the reaction of CpTiCl₃ with N(CH₂CH(CH₃)OH)₃ in the presence of triethylamine. The reaction of CpTi(OMe)₃ (8) with N(CH₂CH₂OH)₂(CH₂CHPhOH), erythro-N(CH₂CH₂OH)₂(CHPhCHPhOH), and N(CH₂CH₂OH)₂(CH₂CPh₂OH) gave cyclopentadienyltitanatranes 12–14. Compound 8 reacts with threo-N(CH₂CH₂OH)₂(CHPhCHPhOH) to give a mixture of threo-CpTi(OCH₂CH₂)₂(OCHPhCHPh)N and threo-MeOTi(OCH₂CH₂)₂(OCHPhCHPh)N. Slow hydrolysis of the latter product gave threo-[Ti₃O(OMe){(OCH₂CH₂)₂₋ (OCHPhCHPh)N} ₃]₂, which was studied by X-ray diffraction analysis. The crystal structures of 3 and 12 were also determined by X-ray diffraction analysis. The titanium coordination polyhedron in these complexes is a distorted trigonal bipyramid in which the equatorial positions are occupied by three oxygen atoms and the axial positions contain the N atom and the Cp group. The titanium—nitrogen distances (2.313(2), 2.291(2) Å in two independent molecules of 3 and 2.271(2) Å in compound 12) confirm the presence of Ti←N transannular interaction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2736–2744, December, 2005.     

Reactions of 1-aryl-2-bromodiazene 1-oxides with acids and bases

The reactions of 1-aryl-2-bromodiazene 1-oxides with HCl in nonaqueous media give aryldiazonium chlorides, while 1,3,3-substituted triazenes-1 are formed in the reactions with secondary amines. Using 2-{¹⁵N} label, it was shown that the aryl group does not migrate in these reactions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 613–615, March, 1997.     

Synthesis of brominated 2-(tert-butyl-NNO-azoxy)anilmes

2-(tert-Butyl-NNO-azoxy)aniline was prepared by selective reduction of 2-(tert-butyl-NNO-azoxy)nitrobenzene. Its bromination yielded the correspondingpara-bromo- andortho, para-dibromoanilines (3a,b).meta-Bromoanilines (6a,b) were synthesized by selective replacement of theortho-bromine atoms in ortho,para-bromo(tert-butylazoxy)benzenes (5a,b) by ammonia in toluene under pressure.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1620–1623, September, 1994.This work was carried out with the financial support of the Russian Foundation for Basic Research (Project No. 93-03-18461).