peri-naphthylenediamines

meta-Substituted “proton sponges” were prepared for the first time by the direct nitration of 5,6-bis(dimethylamino)acenaphthene under strong acidic conditions and by the selective reduction of 1.3,8-tri- and 1,3,6,8-tetranitronaphthalenes and subsequent alkylation of the compounds obtained. 4,5-Bis(dimethylamino)-1,2,3,6,7,8-hexanitronaphthalene was synthesized starting from 1,3,6,8-tetranitronaphthalene. For Part 28, see Ref. 1. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 8, pp. 1405–1411, August, 2000.     

peri-naphthylenediamines

First indirect evidence for the formation of a radical cation of 1,8-bis(dimethylamino)naphthalene (“proton sponge”) in reactions with HNO₃, HNO₂, NO₂, and I₂ has been obtained. In all cases, the products of reaction of the radical cation with nucleophiles and/or its dimer, 4,5,4′,5′-tetrakis(dimethylamino)-1,1′-binaphthyl, have been isolated. 4-Chloro-1,8-bis(dimethylamino)naphthalene has been regioselectively synthesized in high yield. For Part 24, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 320–324, February, 1998.     

peri-Naphthylenediamines

4,5,4′,5′-Tetrakis(dimethylamino)-1,1′-binaphthalene, unknown previously, was obtained in ∼20% yield by the oxidation of 1,8-bis(dimethylamino)naphthalene with Tl(OAc)₃ or Pb(OAc)₄ at low temperatures. Treatment of the reaction product with excess Li and then with O₂ gave, depending on the reaction temperature, perylene or 4,4′-bis(dimethylamino)-1,1′-binaphthalene in good yields, instead of expected 3,4,9,10-tetrakis(dimethyl-amino)perylene. For Part 23, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 93–98, January, 1998.     

A method for determination of the structure of the intramolecular hydrogen bond in the cations of unsymmetrically substituted 1,8-bis(dimethylamino)naphthalenes in solution

Alkylation of 8-dimethylamino-1-methylamino-4-nitronaphthalene in the CD₃I/KOH/DMSO system afforded a 4-nitro derivative containing the N(CD₃)Me group in position 1. Direct proof of the structure of the intramolecular hydrogen bond in solutions of monoprotonated 4-R-1,8-bis(dimethylamino)naphthalenes was obtained for the first time. ¹H NMR study revealed that the chelated NH proton is shifted to the N(8) atom for R = NO₂ and NH₃ ⁺ and to the N(1) atom for R = NH₂. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 159–162, January, 2006.     

Proton sponges-based (2-naphthyl)pyridylmethanol

The action of 2-, 3-, and 4-pyridinecarboxaldehydes on 1,8-bis(dimethylamino)-2-lithium-and 1,8-bis(dimethylamino)-2,7-dilithiumnaphthalenes gave secondary mono-and dicarbinols containing pyridylcarbinol groups at C-2 and C-7 of the proton sponge. Spectral and X-ray diffraction structural data were used to study the molecular structure of these products. Dedicated to Academician B. A. Trofimov, an outstanding organic chemist, who has made a major contribution to the chemistry of acetylenes and nitrogen heterocycles on the occasion of his seventieth jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1409–1417, September, 2008.     

Synthesis of 1,2,4-triazolium 4N-nitroimides by the nitration of 1-substituted 4-amino-1,2,4-triazolium nitrates

A general method for the synthesis of 1,2,4-triazolium 4N-nitroimides with functionalized substituents in position 1 of the heterocycle was developed. The method is based on the nitration of the corresponding 1-R-4-amino-1,2,4-triazolium nitrates.     

peri-Naphthylenediamines

Tertiary alcohols containing the 4,5-bis(dimethylamino)-1-naphthyl group were synthesized. The carbocations that formed from α-methyl-containing alcohols in an acidic medium underwent smooth El elimination to give the corresponding unsaturated derivatives of the “proton sponge” in good yields. At the same time, the carbocation generated from 4-(α-hydroxybenzhydryl)-1,8-bis(dimethylamino)naphthalene was converted into a benzo-[a]fluorene derivative as a result of a complex reaction which has been previously unknown in the chemistry of “proton sponges.” The structure of the latter derivative was established by X-ray diffraction analysis. For Part 26, see Ref. 1; this paper simultaneously presents Part 5 of the series “Resonance-stabilized α-naphthylmethyl carbocations and derived spiro compounds;” for Part 4, see Ref. 2. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1103–1108, June, 2000.     

1-Dimethylamino-2,7-dimethoxy-8-methylamino-3,5-dinitronaphthalene and 1,2,4-tribromo-6-dimethylamino-5-methylaminoacenaphthylene: first examples of N—H...N hydrogen bond contraction/expansion in neutral 1,8-diaminonaphthalenes

1-Dimethylamino-2,7-dimethoxy-8-methylamino-3,5-dinitronaphthalene and 1,2,4-tri-bromo-6-dimethylamino-5-methylaminoacenaphthylene containing the N,N,N′-trimethyl-1,8-diaminonaphthalene fragment with the substituted aromatic ring were studied by X-ray diffraction. Both systems are stabilized by an intramolecular hydrogen bond. The characteristics of the latter are determined by the influence of either the ortho substituents or the peri-annelated five-membered ring. In the former case, the intramolecular hydrogen bond is substantially shortened (N...N, 2.628(5) Å) due to the “buttressing effect” of the o-OMe groups, whereas the peri-dibromoethylene bridge and the Br substituent at position 4 cause a substantial elongation of the intramolecular hydrogen bond (N...N, 2.75(2) and 2.76(1) Å) in the latter case. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2414–2417, November, 2005.     

“<Emphasis Type="Italic">ortho</Emphasis>-Effect” in thermal curtius rearrangement of alkylbenzoyl azides into isocyanates: A quantitative interpretation

The reasons for abnormally high reactivity of ortho-alkylbenzoyl azides in thermal Curtius rearrangement were established by the density functional method (PBE/TZ2P approximation). The key factor responsible for the rearrangement rate is the destabilization of the conjugated structure of arylacyl azide through steric effects of the ortho-substituents. Additional intramolecular hydrogen bonding, as in o-hydroxybenzoyl azide molecule, stabilizes the conjugated structure and increases the energy barrier to the reaction. Quantitative interpretation of the “ortho-effect” is given based on the dependence of the reactivity of ortho-alkylbenzoyl azides on the dihedral angle, which characterizes the extent of coplanarity of the acyl azide group and benzene ring. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 7–13, January, 2007.     

The reaction of salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides with dihalomethanes

Methylene-bis[N′-oxydiazene-N-(β-hydroxyalkyl)N-oxides] were synthesized by the reaction of salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides with diahalomethanes. The effect of the nature of the starting reagents and the reaction condtions on the yields of the target compounds was studied. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2266–2269, November, 1998.     

The Sonogashira coupling of 2- and 4-ethynyl derivatives of proton sponge with 1,8-diiodonaphthalene: Novel cascade transformations into naphtho[1,2-k]fluoranthenes and acenaphtho[1,2-b]benzo[g]indoles

The Sonogashira coupling of 2-ethynyl, 4-ethynyl and 2,7-diethynyl derivatives of 1,8-bis(dimethylamino)naphthalene (proton sponge) with 1-iodo- and 1,8-diiodonaphthalenes has been studied. The reaction of the above alkynes with 1-iodonaphthalene gave the expected naphthylethynyl derivatives of proton sponge. At the same time, the coupling of 2-ethynyl- and 2,7-diethynyl-1,8-bis(dimethylamino)naphthalenes with 1,8-diiodonaphthalene resulted in the formation of N,N,7-trimethyl-7H-acenaphtho[1,2-b]benzo[g]indol-8-amines. The reaction of 1,8-diiodonaphthalene with 4-ethynyl-1,8-bis(dimethylamino)naphthalene produced 14-(4,5-bis(dimethylamino)naphthalen-1-yl)-N¹¹,N¹¹,N¹²,N¹²-tetramethylnaphtho[1,2-k]fluoranthene-11,12-diamine together with 4-((8-iodonaphthalen-1-yl)ethynyl)-N¹,N¹,N⁸,N⁸-tetramethylnaphthalene-1,8-diamine. It was suggested that the mechanisms of the two novel cascade transformations stem from the specific nature of the proton sponge substrates.     

Synthesis and structures of complexes ofN-2-nitroxyethylpicolinamide and 2-(2-pyridyl)-2-oxazoline with PdCl2

The reaction ofN,N′-bis(2-nitroxyethyl)pyridine-2,6-dicarboxamide with PdCl₂ afforded previously unknowncis-(N-2-nitroxyethylpicolinamide-N,N′)dichloropalladium(II) andcis-[2-(2-pyridyl)-2-oxazoline-N,N′]dichloropalladium(II), which were isolated as a cocrystallizate of the molecular compounds. Its structure was established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1604–1606, August, 1999.     

Synthesis of α,α′-bis(R-benzylidene)cycloalkanones catalyzed by potassium hydrogen sulfate under solvent-free conditions

Cyclopentanone or cyclohexanone were condensed with aromatic aldehydes to give corresponding α,α′-bis(R-benzylidene)cyclopentanones or α,α′-bis(R-benzylidene)cyclohexanones. The reaction was catalyzed by potassium hydrogen sulfate with a yield of 84–95% under solvent-free conditions.     

Pseudo-Polymorphs of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-Bis(4-nitrophenyl)-2,6-Pyridinedicarboxamide

Three pseudo-polymorphs of N, N′-bis(4-nitrophenyl)-2,6-pyridinedicarboxamide 1 were characterized by X-ray crystallography. The C–H ⋅s O hydrogen bond was found to contribute significantly to the assembly of this host. With the variation of the guest, the host changed the molecular conformation and the supramolecular synthons. In all three cases concerned, the solvent guests were bonded through direct host-guest interaction and accommodated in the voids formed by the assembly of the host.     

Solvation Structure and Complexation of the Manganese(II) Ion in N,N-Dimethylpropionamide and N,N,N′,N′-Tetramethylurea Studied by Means of Titration Calorimetry and Raman Spectroscopy

Aprotic N,N-dimethylpropionamide (DMPA) and N,N,N′,N′-tetramethylurea (TMU) are both strong donor solvents and coordinate to metal ions through the carbonyl oxygen atom. These solvents show a different conformational aspect in the bulk phase, i.e., DMPA exists as either a planar cis or a nonplanar staggered conformer, while TMU exists in a single planar cis conformer. It has been established that the manganese(II) ion is solvated by five molecules in both solvents. Interestingly, although the planar cis conformer of DMPA is more favorable than the nonplanar staggered one in the bulk phase, the reverse is the case in the coordination sphere of the metal ion, i.e., a conformational change occurs upon solvation. To reveal the thermodynamic aspect of this conformational change, the complexation of Mn(II) with bromide ions in DMPA and TMU has been studied by titration calorimetry at 298 K. It was found that the Mn(II) ion forms mono-, di- and tri-bromo complexes in both solvents, and their formation constants, enthalpies and entropies were obtained. The Δ H∘₁ value for MnBr⁺ strongly depends on the solvent, i.e., it is positive (19.4 kJ-mol⁻¹) in DMPA and negative (−8.7 kJ-mol⁻¹) in TMU, whereas the Δ H^∘₂ and Δ H∘₃ values for the stepwise formation of MnBr₂ and MnBr₃⁻ are both small and negative. The enthalpy of transfer Δ_tH^∘ from DMPA to TMU, which is evaluated on the basis of the extrathermodynamic TATB assumption, is 25.5 kJ-mol⁻¹ for Mn²⁺ and −3.6 kJ-mol⁻¹ for MnBr⁺. These values indicate that the difference between the formation enthalpy of MnBr⁺ in the two solvents, Δ H^∘₁ (DMPA) – Δ H∘₁ (TMU), is mainly ascribed to the value of Δ_tH^∘(Mn²⁺). It is found that the metal ion is also five-coordinated in the monobromo complex, MnBr(DMPA)₄⁺ . The enthalpy for the conformational change of DMPA from its planar cis to the nonplanar staggered form is evaluated to be −11 and −5.5 kJ-mol⁻¹ for Mn(DMPA)₅^{2 +} and MnBr(DMPA)₄⁺, respectively. Note that these values are significantly smaller than the corresponding value (5.0 kJ-mol⁻¹) in the bulk phase. We thus conclude that, although steric hindrance among solvent molecules is reduced by replacing one DMPA of Mn(DMPA)₅^{2 +} with the relatively small bromide ion, DMPA molecules are still sterically hindered in the MnBr(DMPA)₄⁺ complex.     

Synthesis of polystyrene with high melting temperature through BDE/CuCl catalyzed polymerization

No matter what the polymerization manner was, polystyrene with unique highT _m (T _m = 170–285°C) was obtained through polymerization of styrene if the amount of BDE/CuCl catalyst was highly increased (mol ratio: St:CuCl = 25:1-2.5:1). Partial crystallinity of the PSt was observed by characterizations of X-ray diffraction and DSC. Spectra of¹H-NMR and¹³C-NMR showed that syndiotactic structure contained in the obtained PSt was 5% more than that in aPSt (atactic polystyrene). According to the proposed “coordinated radical cage” mechanism, the coordinated state between radical and catalyst center metal Cu should be more closely packed with increasing the BDE/CuCl catalyst amount, which was induced to partial stereospecific polymerization in the coordinated radical polymerization of St.     

A new nortriterpenoid from the deep-sea spongeSarcotragus spinulosus

A new nortriterpenoid from the deep-sea spongeSarcotragus spinulosus was isolated and characterized. The structure of geranylfarnesylacetone was assigned to the new compound on the basis of analysis of its chemical transformations and spectral data. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2072–2074. October, 1998.     

Synthesis of 1-(N-alkylnitraminomethyl)-3-nitroureas usingN-alkylsulfamates

1-(N-alkylnitraminomethyl)-3-nitroureas were prepared by nitration of condensation products of urea with formaldehyde andN-alkylsulfamate.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2041–2042, November, 1994.     

The chemistry ofN,N-bis (trialkylsilyloxy) enamines

The reactions of primary amines withN,N-bis(trimethylsilyloxy) enamines can give products of both mono-and bis-α-oximinoalkylation of primary amines. The steric restrictions in both reactants substantially retard bis-α-oximinoalkylation. A general method for the synthesis of α-amino-substituted oximes from primary amines and bis-silyl derivatives of aliphatic nitro compounds was developed. For Part 1, see Ref. 1. Published inIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1265–1272, July, 2000.     

Determination of DNA by Use of the Molecular “Light Switch” Complex of Ru(bipy)2(dppz)2+

 A novel fluorimetric method has been developed for selective determination of DNA with the molecular “Light Switch” complex of Ru(bipy)₂(dppz)²⁺. The maximum fluorescence intensity was produced in the pH range of 9.3–11.5, with the maximum excitation and emission wavelength of 471.8 nm and 599.8 nm, respectively. Under the optimum conditions, the fluorescence intensity was in proportion to the concentration of DNA. The linear range for calf thymus DNA salmon sperm DNA and herring sperm DNA reaches from the limit of determination to 1.5 μg/mL. The limits of determination for calf thymus DNA salmon sperm DNA and herring sperm DNA are 3.3 ng/mL, 2.8 ng/mL and 4.4 ng/mL, respectively. When the proposed method was used to determine DNA in the presence of some coexisting substances, a satisfactory result was obtained. Received December 29, 1998. Revision June 28, 1999.