6,6′-Bis(1,5-diazabicyclo[3.1.0]hexane)

The interaction of 1,3-diaminopropane with glyoxal and NaOCl in water at pH 9.5–10.5 afforded the previously unknown 6,6′-bis(1,5-diazabicyclo[3.1.0]hexane). According to X-ray diffraction data, both bicyclic fragments of the title compound adopt a boat conformation. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 623–625, March, 1999.     

Synthesis of unsubstituted 1,3,5-triazabicyclo[3.1.0]hexane

Unsubstituted 1,3,5-triazabicyclo[3.1.0]hexane has been syntesized for the first time by treating a Henry solution with NaOCl.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1665–1666, September, 1993.     

1,5-Diazabicyclo[3.1.0]hexanes and 1,6-diazabicyclo[4.1.0]heptanes: a new method for the synthesis,quantum-chemical calculations,and X-ray diffraction study

A new method was developed for the synthesis of 6-substituted 1,5-diazabicyclo[3.1.0]hexanes and 7-substituted 1,6-diazabicyclo[4.1.0]heptanes by condensation of N-monohalotrimethylene- and N-monohalotetramethylenediamines with carbonyl compounds in the presence of bases. X-ray diffraction studies and quantum-chemical B3LYP/6-31G* calculations demonstrated that the conformations of the resulting bicyclic systems are stabilized by stereoelectronic interactions. As a result, a boat conformation prevails in 1,5-diazabicyclo[3.1.0]hexanes, whereas the energies of chair, half-chair, and boat conformations of 1,6-diazabicyclo[4.1.0]heptanes are equalized.     

Molecular structure of 1,2,3-triethyldiaziridine: Gas-phase electron diffraction and theoretical calculations

For the first time, the equilibrium molecular structure and conformational composition (6 to 8 conformers) of 1,2,3-triethyl-diaziridine in the gas phase were determined by gas-phase electron diffraction. Using 1D and 2D ¹H and ¹³C NMR spectro-scopy, it was shown that in a CDCl₃ solution under normal conditions on the NMR time scale, the molecule exists only as one conformer. The enthalpy of formation Δ_fH ⁰₂₉₈ of the studied molecule in the gas phase was calculated by the method of atomization reactions and is equal to 92.2 ± 1.7 kJ mol⁻¹.     

Assembling of 3,6-diazabicyclo[3.1.0]hexane framework in oxidative triflamidation of substituted buta-1,3-dienes

Reaction of trifluoromethanesulfonamide (triflamide) CF₃SO₂NH₂ with 2,3-dimethylbuta-1,3-diene (2) and 2,5-dimethylhexa-2,4-diene (3) in the oxidative system (t-BuOCl+NaI) results in the formation of 2,4-dimethyl- or 2,2,4,4-tetramethyl-3,6-bis(triflyl)diazabicyclo[3.1.0]hexane through two successive heterocyclizations. Reaction of diene (3) with arenesulfonamides ArSO₂NH₂ (Ar=Ph, Tol), stops at the formation of the product of oxidative 1,4-addition, N,N′-(2,3-dimethylbut-2-ene-1,4-diyl)diarenesulfonamides, providing evidence of the essential difference between the reactivity of triflamide and arenesulfonamides.     

Molecular structure of 1,5-diazabicyclo[3.1.0]hexane as determined by gas electron diffraction and quantum-chemical calculations

The equilibrium molecular structure and conformation of 1,5-diazabicyclo[3.1.0]hexane (DABH) has been studied by the gas-phase electron-diffraction method at 20 degrees C and quantum-chemical calculations. Three possible conformations of DABH were considered: boat, chair, and twist. According to the experimental and theoretical results, DABH exists exclusively as a boat conformation of C s symmetry at the temperature of the experiment. The MP2 calculations predict the stable chair and twist conformations to be 3.8 and 49.5 kcal mol(-1) above the boat form, respectively. The most important semi-experimental geometrical parameters of DABH (r(e), A and angle)e), deg) are (N1-N5) = 1.506(13), (N1-C6) = 1.442(2), (N1-C2) = 1.469(4), (C2-C3) = 1.524(7), (C6-N1-C2) = 114.8(8), (N5-N1-C2) = 107.7(4), (N1-C2-C3) = 106.5(9), and (C2-C3-C4) = 104.0(10). The natural bond orbital (NBO) analysis has shown that the most important stabilization factor in the boat conformation is the n(N) --> sigma*(C-C) anomeric effect. The geometry calculations and NBO analysis have been performed also for the bicyclohexane molecule.     

Diastereoselective synthesis of substituted 1,3,6-triazabicyclo[3.1.0]hexanes

A general method was developed for the synthesis of substituted 1,3,6-triazabicyclo[3.1.0]hexanes via intramolecular aminomethylation of the NH group of the diaziridine ring by the reactions of 3-aminomethyl-1,3-dimethyldiaziridine with aliphatic, aromatic, and heteroaromatic carbonyl compounds. These reactions with aldehydes proceeded diastereoselectively to form mixtures of two racemates, viz., 1R*,2R*,5R*,6R* and 1R*,2S*,5R*,6R*, in a ratio of (3—20) : 1, the predominant diastereomer being isolated in all cases. The reactions with symmetrical ketones gave rise exclusively to the (1R*,5R*,6R*) racemate. The predominant diastereomer 1R*,2R*,5R*,6R*-2-(2-bromothien-5-yl)-1,3,6-triazabicyclo[3.1.0]hexane crystallized as a conglomerate. The structure of one of its enantiomers was established by X-ray diffraction analysis.     

Electron Diffraction Study of the Molecular Structure of 6,6'-Bis(1,5-diazabicyclo[3.1.0]hexane)

Gas-phase electron diffraction using quantum-chemical calculations was employed to study the molecular structure for 6,6'-bis(1,5-diazabicyclo[3.1.0]hexane). The conformation of the bicyclic fragment is boat or anti relative to the exocyclic bond.     

Synthesis and transformations of 1,3,5-triazabicyclo[3.1.0]hexanes

The conditions for the condensation of 1,2-nonsubstituted diaziridines with CH₂O and NH₃ (or AlkNH₂) to the corresponding 1,3,5-triazabicyclo[3.1.0]hexanes have been found and 3-phenylsulfonyl, 3-trimethylsilyl, 3-nitroso, and 3-nitro derivatives of the latter have been obtained.For the previous communication, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2091–2095, December, 1993.     

One-pot assembly of 4-methylene-3-oxa-1-azabicyclo[3.1.0]hexanes from alkyl aryl(hetaryl) ketoximes, acetylene, and aliphatic ketones: a new three-component reaction

A new three-component reaction between alkyl aryl(hetaryl)ketoximes, acetylene, and aliphatic ketones in the superbasic systems KOH/DMSO and LiOH/CsF/DMSO (70-90 °C, initial acetylene pressure 13-15 atm, 5-60 min) affords novel 4-methylene-3-oxa-1-azabicyclo[3.1.0]hexanes in yields of up to 75%. Using KOH/DMSO, the side products of the reaction are O-vinylketoximes and 2-aryl(hetaryl)pyrroles, while with LiOH/CsF/DMSO, the reaction proves to be selective, only minor amounts of the corresponding alkyl aryl(hetaryl) ketones being detectable.     

Synthesis and Photochromic Properties of New Heterocyclic Derivatives of 1,3‐Diazabicyclo[3.1.0]Hex‐3‐Ene

The facile synthesis of several 1,3‐diazabicyclo[3.1.0]hex‐3‐ene derivatives with varying substitutions such as 2‐methyl‐6‐(4‐nitrophenyl)‐2,4‐diphenyl‐( 1 ), 2‐methyl‐6‐(4‐nitrophenyl)‐4‐phenyl‐2‐(pyridin‐3‐yl)‐( 2 ), 2‐(furan‐2‐yl)‐6‐(4‐nitrophenyl)‐4‐phenyl‐( 3 ), 2‐(furan‐2‐yl)‐6‐(3‐nitrophenyl)‐4‐phenyl‐( 4 ), 6‐(3‐nitrophenyl)‐2,4‐diphenyl‐( 5 ) and 6‐(4‐chlorophenyl)‐4‐(3‐nitrophenyl)‐2‐phenyl‐( 6 ) that all behave as “intelligent materials” are reported.     

Molecular structure and conformation of diethylmethylamine determined by gas electron diffraction and vibrational spectroscopy combined with theoretical calculations

We have investigated the molecular structure and conformation of diethylmethylamine, C(4)H₃C(2)H₂N(1)[CH₃]C(3)H₂C(5)H₃, by gas electron diffraction and vibrational spectroscopy with the aid of theoretical calculations. Diffraction data are consistent with a conformational mixture of 35(14)% tt + 27(14)% g⁺t + 20(17)% g⁻t + 18(23)% g⁺g⁺ where the numbers in parentheses denote three times the standard errors (3σ). Normal-coordinate analysis based on B3LYP/6-311+G^** calculations supports the existence of the four conformers. The dihedral angle ₁(C4C2N1C3) (= −₂(C5C3N1C2)) of the tt conformer was 170(4)° whereas the ₁ and ₂ values of the other conformers were fixed at the B3LYP/6-311++G(2df,p) values: 72.4° and −163.3° for the g⁺t, −66.0° and −158.2° for the g⁻t, and 60.3° and 63.5° for the g⁺g⁺. Average values of the structural parameters (r_g/Å and _α/°) with 3σ are: r(N–C) = 1.462(2), r(C–C) = 1.523(3), r(C–H) = 1.113(2), CNC = 111.6(5), NCC = 114.5(5), NCH/CCH_Me = 110.6(5).     

Molecular structure of phenylsilane: a study by gas-phase electron diffraction and ab initio molecular orbital calculations

The molecular structure of phenylsilane has been determined accurately by gas-phase electron diffraction and ab initio MO calculations at the MP2(f.c.)/6-31G* level. The calculations indicate that the perpendicular conformation of the molecule, with a Si–H bond in a plane orthogonal to the plane of the benzene ring, is the potential energy minimum. The coplanar conformation, with a Si–H bond in the plane of the ring, corresponds to a rotational transition state. However, the difference in energy is very small, 0.13 kJ mol⁻¹, implying free rotation of the substituent at the temperature of the electron diffraction experiment (301 K). Important bond lengths from electron diffraction are: <r_g(C–C)>=1.403±0.003 Å, r_g(Si–C)=1.870±0.004 Å, and r_g(Si–H)=1.497±0.007 Å. The calculations indicate that the C_ipso–C_ortho bonds are 0.010 Å longer than the other C–C bonds. The internal ring angle at the ipso position is 118.1±0.2° from electron diffraction and 118.0° from calculations. This confirms the more than 40-year old suggestion of a possible angular deformation of the ring in phenylsilane, in an early electron diffraction study by F.A. Keidel, S.H. Bauer, J. Chem. Phys. 25 (1956) 1218.     

Reaction and sensing of octafluorocyclopentene with 1,5-diazabicyclo[4,3,0]non-5-ene

Reactions of octafluorocyclopentene (C₅F₈) with 1,5-diazabicyclo[4,3,0]non-5-ene (DBN) are studied by analyses of an isolated product and optical spectra from the viewpoint of applications to gas-sensors. Obtained results suggest that nucleophilic reactions of DBN proceed toward the double bond of C₅F₈ molecule accompanied with hydroxide anion attack on carbon-fluoride bonds of C₅F₈ moiety under ambients, forming unique C₅F₈-modified adducts. The present reaction is conducive to a new type of technologies for quick and selective sensing that can be used to develop alarm systems in the field of the environment and etching processing factories.     

10-氯-5-二乙氧基甲基-1,3-二甲基色烯并[4,3-d]吡唑并[3,4-b]吡啶-6(3H)-酮的合成和晶体结构

利用L-脯氨酸催化的5-氯水杨醛(1)与6-甲基-4-羟基吡喃酮(2)的缩合反应及硫酸铜催化下与1,3-二甲基-5-氨基吡唑(3)的串联反应,合成得到了10-氯-1,3-二甲基-5-(2-氧代丙基)色烯并[4,3-d]吡唑并[3,4-b]吡啶-6(3H)-酮(4)和10-氯-5-二乙氧基甲基-1,3-二甲基色烯并[4,3-d]吡唑并[3,4-b]吡啶-6(3H)-酮(5).化合物5的结构通过单晶X射线衍射法确定:晶体属于三斜晶系,空间群P-1;相对分子质量Mr=803.68;晶胞参数a=1.03160(10)nm,b=1.42900(13)nm,c=1.44268(15)nm;V=1.9448(3)nm~3;Z=2;晶胞密度Dc=1.372g/cm~3;吸收系数μ=0.228mm-1;单胞中电子的数目F(000)=840.晶体结构用直接法解出,经全矩阵最小二乘法对原子参数进行修正,最终的偏离因子为R=0.0681,w R=0.2051.在晶体结构中色烯环与吡啶环及吡唑环近似于共平面.     

Synthesis of 1,5-(2,6-dimethylpyridyl)-calix[8]arene: solid-state structure of its dicesium complex

Reaction of p-tert-butylcalix[8]arene 1 with 2,6-bis(chloromethyl)pyridine results in the regioselective introduction of the nitrogen-containing heterocycle to the 1 and 5 phenolic positions. The deprotonated form of the 1,5-bridged compound 2 acts as a dianionic ligand toward Cs⁺. The dicesium complex [2·Cs₂O(H₂O)], which has water molecules as additional ligands for the cesium cations, was characterized by X-ray crystallography.     

Perhydroxylcucurbit[6]uril as a highly selective gas chromatographic stationary phase for analytes of wide‐ranging polarity

This work describes the separation performance of a perhydroxylcucurbit[6]uril stationary phase for capillary gas chromatography. The perhydroxylcucurbit[6]uril stationary phase exhibits higher resolving capabilities for critical analytes with better peak shapes than cucurbit[6]uril and conventional stationary phases. The advantageous separation feature of the perhydroxylcucurbit[6]uril stationary phase may originate from its unique structure and favorably balanced interactions with the analytes. Also, the perhydroxylcucurbit[6]uril column shows good separation repeatability with relative standard deviations in the range of 0.01–0.13% for intraday, 0.37–0.82% for interday, and 1.0–4.7% for column‐to‐column repeatability.     

Geometrical and electronic structure of LaI3 molecule from the gas electron diffraction data and quantum chemical calculations

The saturated vapor over LaI₃ has been studied using the electron diffraction method with mass-spectral monitoring. It was determined that at a temperature 1142(10) K, along with monomer molecules, dimers are present in the vapor in the quantity of 0.7 mol.%. Effective configuration parameters of LaI₃ molecule were obtained: r _g(La-I) 2.961(6) Å, ∠_g(I-La-I) 116.5(9)°, l(La-I) 0.106(1) Å and l(I…I) 0.412(7) Å. A small deviation of the valence angle ∠_g(I-L-I) from 120° can be totally caused by a contraction effect of the distance r _g(I…I) of LaI₃ molecule with planar equilibrium configuration. The electronic structure of LaI₃ molecule was examined by the B3LYP/SDD method. In terms of the NBO-analysis, the participation of lanthanum 4f-AO in bonding orbitals La-I is noted. It is shown that the NBO-analysis describes the bond La-I in LaI₃ molecule as predominantly ionic one with a noticeable covalence component. The energy of the heterolytic bond breakage E(La-I)_het = 1216 kJ/mole was calculated.     

Electron diffraction study of molecular structure of mebicar

The structure of the mebicar molecule has been studied by gas-phase electron-diffractometry using quantum chemical calculations. An eclipsed conformation along the C-C bond (torsion angle ?(H-C-C-H) = 10°) and flattened semi-chair conformations of cyclic fragments have been found. The bond lengths (r _g ) and angles (∠α) show the following average values: r(C-C) 1.576(3) Å, r(C-N) 1.460(3) Å, r(C(O)-N) 1.390(4) Å, r(C=O) 1.211(5) Å, r(C-H) 1.090(5) Å, ∠CCN 103.0(5)°, ∠CNC(O) 112.2(1)°, ∠CNC 122.4(1)°. The dihedral angle between the cyclic fragments is 116.6°.     

Molecular structure of bismuth trichloride from combined electron diffraction and vibrational spectroscopic study

The results of an electron diffraction reanalysis, augmented with a combined electron diffraction and vibrational spectroscopic elucidation, of the molecular structure of BiCl₃ are reported. The principal parameters arer _g (Bi-Cl)=2.424±0.005 å (r =2.417±0.005 å) and <Cl-Bi-Cl=97.5±0.2. They are in excellent agreement with previous electron diffraction analysis [1], utilizing a more limited data range from the same experiment. They are also fully consistent with the expected trends of geometrical variation in the Group V trihalide series. The force fields of BiCl₃, determined by normal coordinate analysis and by combined analysis, agree within experimental error.