Synthesis of nitro- and aminoindoles

Optimal conditions are proposed for the direct nitration of 2,3-dimethylindoles containing methyl and methoxy groups in the benzene ring. In contrast to 5- and 6-methylindoles and 5- and 6-methoxyindoles, nitration of 7-methyl-and 7-methoxy-2,3-dimethylindoles proceeds differently under the same conditions. A series of previously unreported aminoindoles was obtained by reduction of the nitroindoles.Mordova State Pedagogical Institute, 430007 Saransk, Russia; e-mail:mgpi@si.moris.ru and M. V. Lomonosov State University, 119899 Moscow, Russia, e-mail:yumar@org.chem.msu.su. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1630–1636, December, 1999.     

Synthesis and properties of nitro-1,2,3-triazoles (Review)

Published data on methods for the synthesis of substituted 4(5)-nitro-1,2,3-triazoles and their properties are reviewed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 3–25, January, 2008.     

Synthesis and crystal structures of two isomeric nitro-α-resorcylic acids

Nitration of α-resorcylic acid (3,5-dihydroxybenzoic acid) to 3,5-dihydroxy-2-nitrobenzoic acid (1) and 3,5-dihydroxy-4-nitrobenzoic acid (2), their separation, and crystallization is described. Crystal structures of 1, 1 · 3H₂O, and 2 were determined by X-ray single-crystal diffraction analysis and compared with DFT-calculated structures. An intramolecular hydrogen bond between the nitro group and o-hydroxyl group(s) occurs in all investigated structures. Intermolecular hydrogen bonds and π···π stacking interactions determine the molecular packing. Additionally, N···O interactions have a crucial role in arrangement of the molecules in the crystal structures of 1 and 2. DFT calculations in the gas phase and in the solution reveal that minor product 2 is a more stable regioisomer than 1, the major product in the nitration reaction.     

Synthesis of polyformals from nitro- and fluordiols. Substituent and chainlength effects

A series of primary and secondary diols carrying nitroalkyl, nitro, and fluoro substituents was reacted with formaldehyde under conditions of acid catalysis. Short-chain primary diols gave cyclic formals while predominantly linear polymers were obtained beginning with pentane-1,5-diols and hexane-1,6-diols, depending upon the nature of the substituents. No polymers were formed from secondary diols with 1-nitroalkyl substituents. The effect of monomer structure on polymer formation is discussed. The polymers obtained were characterized by GPC and end group analysis.     

Intramolecular catalysis in the hydrolysis of aminoalkylphosphonates

Conclusions The kinetics of a reaction with water was investigated for diethyl esters of-,-, and-aminoalkylphosphonic acids. The reactivity of the neutral forms of the esters in the studied reaction was elevated because of intramolecular catalysis by the amino group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2220–2223, October, 1982.     

Acetylenic derivatives of nitro- and aminonaphthalenes

Conclusions We synthesized a number of acetylenic and diacetylenic alcohols, which are derivatives of nitro- and aminonaphthalenes by the condensation of substituted halonaphthalenes with acetylenic alcohols.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 407–409, February, 1984.     

Synthesis and reactions of halo-, nitro-, and arylazo-substituted 3-acetyltropolones. Formation of heterocycle-fused troponoid compounds

3-Acetyltropolone ( 1 ) reacted with bromine, iodine, and nitric acid to afford respectively 3-acetyl-5,7-di-bromotropolone ( 2 ), 3-acetyl-7-iodotropolone ( 3 ), and 3-acetyl-5-nitro- ( 4 ) and 3-acetyl-5,7-dinitrotropolone ( 5 ). Azo-coupling reactions of 1 gave 3-acetyl-5-arylazotropolones 7a-f. The Schmidt reactions of 2 and 3 gave respectively 5,7-dibromo- ( 9 ) and 7-iodo-2-methyl-8H-cyclohept[d]oxazol-8-one ( 10 ), while 4 gave 3-acetamido-5-nitrotropolone ( 11 ). Compounds 2 and 4 reacted with hydroxylamine to give 3-methyl-8H-cyclohept[d]isoxazol-8-ones 12 and 13. The reactions of 2 , 3 , and 4 with hydrazine gave 3-methyl-1,8-dihydrocycloheptapyrazol-8-ones 15 , 16 , and 17.     

Synthesis and reactions of halo-, nitro-, and arylazo-substituted 3-cinnamoyltropolones. Formation of styryl-substituted heterocycle-fused troponoid compounds

3-Cinnamoyltropolone ( 1 ) reacted with bromine to afford 7-bromo- ( 2 ), 5,7-dibromo-3-cinnamoyltropolone ( 3 ), and 6,8-dibromo-4,9-dihydrocyclohepta[b]pyrane-4,9-dione ( 4 ) according to amount of the reagent. Iodination and nitration of 1 gave respectively 7-iodo- ( 5 ) and 5-nitro-3-cinnamoyltropolone ( 6 ). Azo-coupling reactions gave 5-arylazo-3-cinnamoyltropolones 7a-f . Compounds 1, 2, 3 and 5 reacted with hydroxylamine to give 3-styryl-8H-cyclohept[d]isoxazol-8-ones 10-13 , while 6 and 7a gave 5-nitro-3-styryl-8H-cyclohept[d]-isoxazol-8-one oxime ( 14 ) and 2-cinnamoyl-7-methoxy-4-phenylazotropone ( 15 ), respectively. The reactions of 1,3 , and 5 with phenylhydrazine gave 3-styryl-1,8-dihydrocycloheptapyrazol-8-ones 16-19 .     

Planar and out-of-plane normal vibrations of nitro- and aminobenzenes

The normal vibrations of halogenobenzenes with a polyatomic para substituent (NO₂, NH₂ ) are reported.The specific vibrations of NO₂ and NH₂ groups and of the CN and CX bonds (X is F, Cl, Br, I) have been assigned using the G.F. method of Wilson. The potential energy distribution shows that the inplane and outofplane vibrations of CN bonds exhibit different behaviour in nitro and aminobenzenes. Indeed, the CN stretching and planar bending are vibrational modes coupled respectively with the symmetric deformation and rocking of NO₂ whereas in the case of the amino molecules they are coupled with the skeletal modes only. Consequently the CN planar bending vibrations have frequencies lower than the CX ones in the nitro compounds. In contrast, the CN bending frequencies are higher in the amino molecules. For the outofplane bending of amino and nitro molecules the γ(CN) frequencies are always higher than γ(CX) frequencies because there is no coupling with the wagging of the polyatomic substituent. Our experimental results by Raman spectroscopy are in good agreement with the theoretical calculations we have performed. They also agree with the spectra published by other authors. We have recorded the splitting of some NO₂ bands in pdinitrobenzene, which is probably due to isomeric positions of the two NO₂ groups relative to the plane of the skeleton.     

Synthesis, structures and electrochemical properties of nitro- and amino-functionalized diiron azadithiolates as active site models of Fe-only hydrogenases

Complex [[(mu-SCH2)2N(4-NO2C6H4)]Fe2(CO)6] (4) was prepared by the reaction of the dianionic intermediate [(mu-S)2Fe2(CO)6](2-) and N,N-bis(chloromethyl)-4-nitroaniline as a biomimetic model of the active site of Fe-only hydrogenase. The reduction of 4 by Pd-C/H2 under a neutral condition afforded complex [[(mu-SCH2)2N(4-NH2C6H4)]Fe2(CO)6] (5) in 67 % yield. Both complexes were characterized by IR, 1H and 13C NMR spectroscopy and MS spectrometry. The molecular structure of 4, as determined by X-ray analysis, has a butterfly 2Fe2S core and the aryl group on the bridged-N atom slants to the Fe(2) site. Cyclic voltammograms of 4 and 5 were studied to evaluate their redox properties. It was found that complex 4 catalyzed electrochemical proton reduction in the presence of acetic acid. A plausible mechanism of the electrocatalytic proton reduction is discussed.     

Synthesis and X-ray crystallographic studies of novel proton-ionizable nitro- and halogen-substituted acridono-18-crown-6 chromo- and fluorogenic ionophores

Starting from acridono-18-crown-6 ligand 1 (Fig. 1) seven new proton-ionizable chromogenic and fluorogenic ionophores 2-8 (Fig. 1) containing NO₂ group(s) and/or Br or Cl atom(s) in the aromatic rings were prepared by electrophilic substitution. The precursor macrocycle 1 was obtained by a modification of the reported procedure which made chromatography unnecessary in purification and gave higher yield. X-ray crystallographic studies of the complexes of acridono-18-crown-6 type ligands 1, 2, 3, 6 and 8 show that the proton-ionizable units are in the acridone tautomeric form and that the ligands invariably bind a water molecule in their cavities by multipodal hydrogen bonding. In two cases (6 and 8) an additional DMF solvent molecule is also bound at the crown perimeter in the solid state.     

Mass-spectrometric behavior of isomeric nitro- and nitroaminoindolizines and indoles

Peaks of [M — NO]⁺ and [M — NO₂]⁺ ions are characteristic for the mass spectra of nitroindolizines, whereas peaks of ions of the indole type, viz., [M — HCN]⁺ and [M- H,- HCN]⁺ (for alkylindoles), are not characteristic. In the mass spectra of nitroindoles the latter ions give more intense peaks, while the loss of a nitro group or its rearrangement is a considerably less significant process. When a dialkylamino group is introduced in the nitroindolizine molecule, the primary processes in the fragmentation of such compounds are due to fragmentation of the alkylamino group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 765–768, June, 1982.     

Benzindoles. 24. Reduction of nitro-2,3-dimethyl[4,5]- and nitro-2,3-dimethyl[6,7]benzindoles

The reduction of nitro-2,3-dimethyl[4,5]- and -[6,7]benzindoles was studied; Benzindoles were obtained with an amino group in the benzene ring. Individual isomers can be separated as the acyl derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1481–1484, November, 1986.     

Microgram detection of phenols and determination of nitro- and nitroso-phenols

The microgram detection of phenols and determination of nitro- and nitroso-phenols is based on their treatment in alkaline solution with a chlorinated hypochlorite solution, resulting in characteristic colours. Ion-exchange resin beads are used to make the test sensitive and selective. A few nitro and nitroso compounds have been determined spectrophotometrically.     

Synthesis of a High-Energy-Capacity Compound,Tetrammine-cis-bis(nitro-2H-tetrazolato-N2)cobalt(III) Perchlorate

The conditions for preparing tetrammine-cis-bis(nitro-2H-tetrazolato-N ²)cobalt(III) perchlorate and the nature of impurities affecting the yield and purity of the target product were studied. The compound can be efficiently prepared using microwave heating.     

Enthalpies of formation of nitro-, nitroxy-, and nitrosoadamantanes

The enthalpies of formation of nitro-, nitroso-, and nitroxyadamantanes were calculated using semiempirical quantum-chemical PM3, MINDO, AM1, and MNDO methods incorporated into MOPAC software package. The best correlation with the experimental data was obtained with the results of PM3 calculations. Using the corresponding linear regression equation, the enthalpies of formation of 22 adamantane derivatives having nitro-, nitroso-, and nitroxy groups were calculated.