Synthesis of amino-substituted 1,3-bis(tert-butyl-NNO-azoxy)benzenes 2.* 2-amino and 2,4-diamino derivatives

Oxidation of one of the amino groups of 2-bromo-4,6-dichloro-1,3-phenylenediamine to the nitroso group followed by its conversion into thetert-butyl-NNO-azoxy group afforded a derivative ofm-(tert-butyl-NNO-azoxy)aniline,viz., 2-bromo-3-(tert-butyl-NNO-azoxyl)-4,6-dichloroaniline. Analogously, the second amino group was converted into thetert-butyl-NNO-azoxy group to form a derivative of 1,3-bis(tert-butyl-NNO-azoxy)benzene,viz., 3-bromo-2,4-bis(tert-butyl-NNO-azoxyl)-1,5-dichlorobenzene The reaction of the latter with ammonia yielded 2-amino- and 2,4-diamino-substituted 1,3-bis-(tert-butyl-NNO-azoxyl)benzenes. For Part 1, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2126–2130, November, 1999.     

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).     

Synthesis and characterization of bis(glycosylamino)benzenes based on reducing disaccharides

Synthesis of bis(glycosylamino)benzenes, derived from disaccharides lactose, maltose, and cellobiose, by direct condensation and their characterization are described. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1235–1238, May, 2005.     

Exchange reactions of 1,3-bis(nitroarylthio)propanes with propane-1,3-dithiols

Base-catalyzed reactions of propane-1,3-dithiols with 2-chloronitrobenzene, 3,4-dichloronitrobenzene, and 2-chloro-3-nitropyridine afforded 1,3-bis(nitroarylthio)propanes, whose thiolate-thiolate exchange with propane-1,3-dithiols gave dihydrobenzodithiepines. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 163–166, January, 2006.     

1,3-bis(2,4,6-trinitrophenylaminooxy)propane and its 4-cyano-2,6-dinitrophenyl congener: Synthesis and properties

Starting from N-hydroxyphthalimide (5) and 1,3-dibromopropane (6) we obtained 1,3-bis(phthalimidooxy)propane (7) which led to 1,3-bis(aminooxy)propane dihydrochloride (8). From its reaction with picryl chloride or 4-cyano-2,6-dinitrochlorobenzene, the two title compounds (4b, 4a) were obtained. ¹H-NMR and ¹³C-NMR spectra are presented. For comparison with the analogous N-methoxy-2,6-dinitro-4-R-anilines 1a, 1b (R=CN or R=NO₂), wer report the hydrophobic characteristics (by RPTLC), electronic spectra for the neutral compounds and their anions, pK _a values, and the behavior towards oxidizers (DPPH, PbO₂, Pb(CH₃COO)₄, KMnO₄ and Ag₂O); DPPH converts compounds 1a, 1b and 4a, 4b into betainic structures 2a, 2b respectively.     

Functionalization of sterically hindered <Emphasis Type="Italic">o</Emphasis>-benzoquinones: amino-substituted 3,6-di(<Emphasis Type="Italic">tert</Emphasis>-butyl)-<Emphasis Type="Italic">o</Emphasis>-benzoquinones

New sterically hindered functionalized o-quinones were synthesized by the 1,4-nucleophilic addition of secondary cyclic amines to 3,6-di(tert-butyl)-o-benzoquinone. The ability of these o-quinones to form o-semiquinone complexes with transition and main-group metals was studied by ESR spectroscopy in solution. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1786–1793, September, 2007.     

Synthesis of 1,7-bis(carboxyalkylcarbamoyl)-m-carboranes as precursors of possible water-soluble preparations for boron-neutron-capture treatment of cancer

By the interaction of the corresponding amino acids with the dichloride ofm-carboranedicarboxylic acid, 1,7-bis-(carboxyalkylcarbamoyl)-m-carboranes were prepared are characterized for the first time. These compounds are of interest as intermediates for the synthesis of water-soluble preparations for the boron-neutron-capture therapy of cancer.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11 pp. 2803–2804, November 1996.     

The tert-butyl-NNO-azoxy group in the synthesis of 1,2,4-benzotriazin-3(4H)-one 1-oxides

Treatment of 2-(tert-butyl-NNO-azoxy)anilines with phosgene at 20 °C was proposed as a novel route to 1,2,4-benzotriazin-3(4H )-one 1-oxides. This method involves a new reaction, viz., an intramolecular interaction of the tert-butyl-NNO-azoxy group with a C-electrophile (leading to the formation of the N(2)—C(3) bond of the triazine ring) followed by elimination of the tert-butyl group. Complete assignment of the signals in the ¹H and ¹³C NMR spectra of the compounds obtained was performed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1507–1509, August, 2007.     

Quinonimines and aminoquinones, the reaction products of 3,6-di(tert-butyl)-o-benzoquinone with primary and secondary amines

Reactions of 3,6-di(tert-butyl)-o-benzoquinone with primary amines occur by the nucleophilic 1,4-addition mechanism and lead to the corresponding 2-hydroxy-p-quinonimines, which exist in solutions in equilibrium with tautomeric 4-amino-o-quinones. The thermodynamic parameters of this prototropic isomerism were determined by NMR spectroscopy. In the case of a secondary amine (piperidine), a derivative of 4-amino-o-quinone was obtained; the corresponding o-semiquinone complexes were studied in solution by ESR spectroscopy. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1151–1155, July, 2006.     

Synthesis of 3-cyano-4,6-dinitrobenzo[d]isoxazole and its reactions with anionic nucleophiles

The action of various anionic O-, N-, and S-nucleophiles on 3-cyano-4,6-dinitro-benzo[d]isoxazole mostly resulted in regiospecific nucleophilic substitution for the nitro group in position 4. With an excess of an nucleophilic reagent, the nitro group in position 6 was also replaced. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 523–528, March, 2006.     

Trisubstituted 1,3,5-Triazines. 5. Reaction of 2,4,6-Tris[di(tert-butoxycarbonyl)nitromethyl]-1,3,5-triazine with Nucleophiles

The reaction of 2,4,6-tris[di(tert-butoxycarbonyl)nitromethyl]-1,3,5-triazine with ammonia, amines, and hydrazine has been studied. It was possible to substitute one of the di(tert-butoxycarbonyl)nitromethyl groups in this compound in the presence of ammonia, primary aliphatic amines, dimethylamine, and morpholine. The reaction with hydrazine leads to both mono- and disubstituted products. A double dealkoxylation occurs in the presence of diethylamine to give the bis(dimethylammonium) salt of 2,4-bis(tert-butoxycarbonylnitromethyl)-6-[di(tert-butoxycarbonyl)nitromethyl]-1,3,5-triazine.     

Paradigms and Paradoxes: Resonance Stabilization in Diazophenoxides (Quinone Diazides)

Diazophenoxides (quinone diazides) constitute an interesting class of compounds that are seemingly high-energy species on the nonaromatic/aromatic interface. With appropriate substitution and/or annelation, they have found use in the fields of explosives, medicine, and photolithography. Thermochemical information about them is sparse. To aid further understanding of these important chemical species, the current paper discusses a few extant enthalpies of formation from which we tentatively derive a resonance energy of ca. 15 kJ-mol^–1 for the parent, p-species, 4-diazo-2,5-cyclohexadiene-1-one. Interestingly, this value is nearly identical to that recently found for the likewise conjugated diazo compound, ethyl diazoacetate.     

Direct Amination of Nitroquinoline Derivatives via Nucleophilic Displacement of Aromatic Hydrogen

The vicarious nucleophilic substitution of hydrogen (VNS) reaction in electron-deficient nitroquinolines was studied. Properties of all new products have been characterized by several techniques: MS, HRMS, FTIR, GC-MS, electronic absorption spectroscopy, and multinuclear NMR. The structures of 4-chloro-8-nitroquinoline, 8-(tert-butyl)-2-methyl-5-nitroquinoline, 9-(8-nitroquinolin-7-yl)-9H-carbazole and (Z)-7-(9H-carbazol-9-yl)-8-(hydroxyimino)quinolin-5(8H)-one were determined by single-crystal X-ray diffraction measurements. The 9-(8-nitroquinolin-7-yl)-9H-carbazole and (Z)-7-(9H-carbazol-9-yl)-8-(hydroxyimino)quinolin-5(8H)-one illustrate the nitro/nitroso conversion within VNS reaction. Additionally, 9-(8-isopropyl-2-((8-isopropyl-2-methyl-5-nitroquinolin-6-yl)methyl)-5-nitrosoquinolin-6-yl)-9H-carbazole is presented as a double VNS product. It is postulated that the potassium counterion interacts with the oxygen on the nitro group, which could influence nucleophile attack in that way.     

Regiospecificity of nucleophilic substitution in 4,6-dinitro-1-phenyl-1H-indazole

The reactions of 4,6-dinitro-1-phenyl-1H-indazole with anionic nucleophiles RS^– and N₃ ^– lead to the regiospecific replacement of the nitro group at position 4. The reaction with N₂H₄·H₂O + FeCl₃ also results in reduction of only the 4-NO₂ group. Based on this fact, a procedure was developed for the preparation of previously unknown 3-unsubstituted 4-X-6-nitro-1-phenyl-1H-indazoles (X is a residue of a nucleophile or NH₂). Comparison of the data on the selective nucleophilic substitution (4-NO₂ group) in 3-Z-1-aryl-4,6-dinitro-1H-indazoles shows that in the case of Z = H, the regiospecificity of substitution is determined by the electronic effect of the annelated pyrazole ring.     

Pentacoordination of boron, carbon, aluminum, and silicon atoms in organic compounds: Anab initio study

Pentacoordination of boron, carbon, aluminum, and silicon atoms in bicyclic organic compounds of the pentalene type was studied using theab initio RHF/6-31G^** and MP2(full)/6-31G^** methods. It was shown that the ability of the atom to form pentacoordinate structures increases on going from B to Al and from C to Si atom,i.e. as the number of the element of Groups IIIA and IVA of the periodic system increases. At the same time, the reverse tendencies are observed in the 2nd and 3rd periods of the periodic system,viz., the ability of the atom to form pentacoordinate structures increases on going from C to B and from Al to Si atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1238–1245, July, 1999.     

Reaction of 4,6-bis(tert-butyl)-2,2,2-trichlorobenzo[d]-1,3,2-dioxaphosphole with phenylacetylene. ipso-Substitution of the tert-butyl group

The reaction of 4,6-bis(tert-butyl)-2,2,2-trichlorobenzo[d]-1,3,2-dioxaphosphole with phenylacetylene follows the mechanism of ipso-substitution of the tert-butyl group that is in para-position relative to the endocyclic O atom of the heterocycle, predominantly yielding 8-(tert-butyl)-2,6-dichloro-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinine (NMR data). The structure of its hydrolysis product, 8-(tert-butyl)-6-chloro-2-hydroxy-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinine, was proved by X-ray diffraction analysis.     

Synthesis of substituted 2-amino-4,6-bis(nonafluoro-tert-butyl)-1,3,5-triazines

A procedure was developed for the synthesis of substituted 2-amino-4,6-bis(nonafluoro-tert-butyl)-1,3,5-triazines from 2-chloro-4,6-bis(nonafluoro-tert-butyl)-1,3,5-triazine and aliphatic and aromatic amines. The data of¹⁹F NMR spectroscopy are indicative of the presence of a barrier to internal rotation. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1568–1572, August, 1999.     

5,7-Dichloro-1,3-dithiolo[4,5-d]pyrimidine-2-thione and -2-Selone: Synthesis, Crystal Structure, Solvatochromism, and Reactions with Nucleophiles

We have obtained for the first time the halo derivatives of a novel heterocyclic system, 1,3-dithiolo[4,5-d]pyrimidine-2-thione and -2-selone, by reaction of 5,7-dioxo(4H,6H)-1,3-dithiolo[4,5-d]pyrimidine-2-thione and -2-selone with POCl₃. The crystal structure of thione confirms that we had obtained the desired compound. The electronic absorption spectra reveal an interesting solvatochromism connected with the appearance of low-intensity n transitions from selenium and sulfur atoms in the visible region of the spectrum. The chlorine atoms in the studied compounds have significant mobility in reactions with nucleophiles (amines, thiourea, azidione), which ensures that new derivatives of 1,3-dithiolo[4,5-d]pyrimidine-2-selone are obtained, and specifically 7-N,N-dialkylamino, 7-N-alkyl-N-arylamino derivatives and 7-isothiuronium salts. The 2-selones obtained can be used in synthesis of new tetrathiafulvalenes.     

Modelling tyrosinase monooxygenase activity. Activation of dioxygen by dicopper(I) complexes and characterisation of dicopper(II) complexes

Activation of dioxygen on dicopper(I) centres was systematically investigated using a group of open-chain and a macrocyclicm-xylyl-based dinucleating ligand from a bioinorganic viewpoint. Even though intermediate peroxodicopper(II) species was not detected (even at −80°C for the open-chain system), the putative intermediate reacted with C–H groups in ligands giving oxygenated products (C–OH groups). Absorption, spectroscopic and magnetic properties of the final dicopper(II) complexes have been investigated.     

A reaction of 3,6-di(tert-butyl)-4-chloro-1,2-benzoquinone with potassium ethyl xanthate. New sulfur-containing o-quinones

In a reaction of 3,6-di(tert-butyl)-4-chloro-1,2-benzoquinone with potassium ethyl xanthate, the halogen atom was replaced by the ethyl xanthate group. Acid hydrolysis of the product gave 4,7-di(tert-butyl)-5,6-dihydroxy-1,3-benzodithiol-2-one containing a pyrocatechol fragment, which was oxidized into the corresponding quinone. When irradiated in solution with visible light, this quinone quantitatively eliminated a CO molecule with contraction of the ring to a five-membered one. The quinones obtained were studied as ligands in coordination spheres of metals by ESR spectroscopy. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 683–686, April, 2006.