Heterotricyclodecane X. 2-Oxa-7-thia-isotwistan und 2-Oxa-7-thia-twistan sowie Derivate

The synthesis of 2-oxa-7-thia-isotwistane ( 11 ) and 2-oxa-7-thia-twistane ( 22 ) as well as of several of their derivatives is described starting from endo-2-hydroxy-9-thiabi cyclo[3.3.1]non-6-ene ( 4 ). The 10^O(2)-isotwistane bromide 13 , iodide 14 and tosylate 30 as well as the 10^S(7)-isotwistane iodide 15 , tosylate 20 , and the 10^S(7)-twistane tosylate 21 were treated under reaction conditions suitable for molecular rearrangements involving the epi-sulfonium ion i and the oxonium ion g . respectively, by neighbouring group participation.     

Two Energetic Ionic Salts of en·PA·H2O and en·TNR: Preparation,Structural Characterization,and Properties

Energetic salts of en · PA · H₂O and en · TNR were synthesized by using ethylenediamine and picric acid (PA) or 2,4,6‐trinitroresorcinol (TNR) as raw materials, and their structures were characterized by elemental analysis and FT‐IR spectroscopy. Single crystals of the title salts were obtained and their structures were determined by single‐crystal X‐ray diffraction. The thermal decomposition behaviors were investigated by DSC and TG‐DTG technologies, furthermore the non‐isothermal kinetic parameters and enthalpies of formation for the salts were calculated. Their combustion heats were measured by oxygen bomb calorimetry and their enthalpies of formation were also calculated based on the combustion heat data. In addition, the detonation pressure (P) and detonation velocities (D) of the salts were predicted by using the K‐J equations. The results indicated that the title salts have potential applications in the field of energetic materials.     

Heterotricyclodecane XI,Sulfoxide und Sulfone von 2-Oxa-7-thia-isotwistan und 2-Oxa-7-thia-twistan sowie Derivaten

The synthesis of sulfoxides and sulfones of 2-oxa-7-thia-isotwistane ( 24 ) and 2-oxa-7-thia-twistane ( 35 ) as well as of several of their derivatives is described. endo-2-Hydroxy-9-thiabicyclo[3.3.1]non-6-ene ( 5 ) was used as starting material. During the course of the reactions special attention was given to intramolecular hydroxy-mercuration and jododemercuration reactions, spectroscopic features, molecular rearrangements and stereospecificity of oxidations of sulfides to sulfoxides.     

Experimental Evidence of Intramolecular CAr–H···O=C Hydrogen Bonds in the Structure of (Diaryl)tetrahydrofuranones Using Spectroscopic Tools

The occurrence of bifurcate H‐bonds C_Ar–H···O=C in the structure of (diaryl)‐tetrahydrofuranones was experimentally demonstrated using different methods and techniques. The consistent increasing spin–spin coupling constants ¹J(C,H) of the ortho‐H‐atoms and low‐field shift of v_C=O in IR spectra of 2,2‐(diaryl)tetrahydrofuran‐3(2H)‐ones relative to their 5,5‐diaryl counterparts, as well as pronounced dependence of the ortho‐C–H H‐atoms chemical shifts on the temperature and solvent polarity along with X‐ray diffraction analysis data unambiguously point to the existence of weak C_Ar–H···O=C H‐bonds in these molecules.     

Partialsynthese der Grandidone A, 7-Epi-A,B, 7-Epi-B,C, D und 7-Epi-D aus 14-Hydroxytaxodion

Partial Synthesis of Grandidones A, 7-Epi-A, B, 7-Epi-B, C, D and 7-Epi-D, from 14-Hydroxytaxodione Oxydative addition of coleon U ( 6 ) to 14-hydroxytaxodione ( 5 ) in the presence of Fétizon's reagent mainly leads to grandidone A ( 1a ) and 7-epigrandidone A ( 1b ) (ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7-epigrandidone B ( 2b ) (ca. 3:1). Dimerization of 14-hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7-epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7-epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved. Oxydative addition of coleon U ( 6 ) to 14-hydroxytaxodione ( 5 ) in the presence of Fétizon's reagent mainly leads to grandidone A ( 1a ) and 7-epigrandidone A ( 1b ) (ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7-epigrandidone B ( 2b ) (ca. 3:1). Dimerization of 14-hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7-epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7-epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved. Oxydative addition of coleon U ( 6 ) to 14-hydroxytaxodione ( 5 ) in the presence of Fétizon's reagent mainly leads to grandidone A ( 1a ) and 7-epigrandidone A ( 1b ) (ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7-epigrandidone B ( 2b ) (ca. 3:1). Dimerization of 14-hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7-epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7-epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved. Oxydative addition of coleon U ( 6 ) to 14-hydroxytaxodione ( 5 ) in the presence of Fétizon's reagent mainly leads to grandidone A ( 1a ) and 7-epigrandidone A ( 1b ) (ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7-epigrandidone B ( 2b ) (ca. 3:1). Dimerization of 14-hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7-epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7-epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved.     

A reinvestigation of the collisional activation mass spectra of [C7H7]+ ion mixtures

The collisional activation (CA) mass spectra of the two isomeric [C₇H₇]⁺ ions, benzyl and tropyl, have been reassessed. The structure-characteristic feature of their CA mass spectra, the m/z 77:74 abundance ratio, has been confirmed as 3.15 ± 0.2 for benzyl cations and lowered to 035 ± 03 for tropyl ions. Benzyl–tropyl cation mixture analyses were made and were in general agreement with earlier CA results, but still disagree with the results of ion cyclotron resonance experiments. The behavior of toluene molecular ions close to their dissociation threshold to [C₇H₇]⁺ + H˙ was examined; for metastable [C₇H₈]⁺˙ ions an approximately 55:45 benzyl:tropyl ratio was found. Observations are discussed in relation to photoionization and photoelecrron-photoionization coincidence studies, both of which predict high tropyl ion contents at low energies. However, at the lowest energies attainable in this study the benzyl content failed to fall below 50% and it is concluded that toluene molecular ions do not generate tropyl cations at their dissociation limit.     

B7Be6B7: A Boron-Beryllium Sandwich Complex

Planar boron clusters have often been regarded as “π-analogous” to aromatic arenes because of their similar delocalized π-bonding. However, unlike arenes such as C₅H₅⁻ and C₆H₆, boron clusters have not previously shown the ability to form sandwich complexes. In this study, we present the first sandwich complex involving beryllium and boron, B₇Be₆B₇. The global minimum of this combination adopts a unique architecture having a D_6h geometry, featuring an unprecedented monocyclic Be₆ ring sandwiched between two quasi-planar B₇ motifs. The thermochemical and kinetic stability of B₇Be₆B₇ can be attributed to strong electrostatic and covalent interactions between the fragments. Chemical bonding analysis shows that B₇Be₆B₇ can be considered as a [B₇]³⁻[Be₆]⁶⁺[B₇]³⁻ complex. Moreover, there is a significant electron delocalization within this cluster, supported by the local diatropic contributions of the B₇ and Be₆ fragments.     

Structures and stability of N7+ and N7− clusters

Ab initio molecular orbital theory and density functional theory have been used to study nine isomers of N₇ ionic clusters with low spin at the HF/6-31G*, MP2/6-31G*, B3LYP/6-31G*, and B3LYP/6-311(+)G* levels of theory. All stationary points are examined with harmonic vibrational frequency analyses. Four N₇ ⁺ isomers and five N₇ ⁻ isomers are determined to be local minima or very close to the minima on their potential-energy hypersurfaces, respectively. For N₇ ⁺ and N₇ ⁻, the energetically low lying isomers are open-chain structures (C _{2 v} and C _{2 v} or C₂). The results are very similar to those of other known odd-number nitrogen ions, such as N₅ ⁺, N₉ ⁺, and N₉ ⁻, for which the open-chain structures are also the global minima. This research suggests that the N₇ ionic clusters are likely to be stable and to be potential high-energy-density materials if they could be synthesized. Received: 16 July 2001 / Accepted: 8 October 2001 / Published online: 21 January 2002     

Synthesis of 7-hydroxythioridazine and 7-hydroxysulforidazine

The thioridazine metabolites 7-hydroxythioridazine (2a) and 7-hydroxysulforidazine (2b) were synthesized. Commercial 4-chloro-3-nitrophenylmethylsulfone was converted to the corresponding 4-thiol through an intermediate xanthate ester. Subsequent zinc metal reduction provided the 3-amino thiolate. This salt was condensed with chloroquinone to yield 7-hydroxy-2-methylsulfonylphenothiazine which was then protected as the isopropyl ether. N-Alkylation with 2-(2-chloroethyl)-1-methylpiperidine using sodium hydroxide, then ether cleavage, afforded 2b . The N-alkylation followed by reduction with diisobutylaluminum hydride and deblocking yielded 2a . These reference standards will assist in an exploration of the potential role of meta-bolically formed 2a and 2b in the neuroleptic response to thioridazine.     

Van Der Waals heterogeneous layer‐layer carbon nanostructures involving π···H‐C‐C‐H···π···H‐C‐C‐H stacking based on graphene and graphane sheets

Noncovalent interactions involving aromatic rings, such as π···π stacking, CH···π are very essential for supramolecular carbon nanostructures. Graphite is a typical homogenous carbon matter based on π···π stacking of graphene sheets. Even in systems not involving aromatic groups, the stability of diamondoid dimer and layer‐layer graphane dimer originates from C − H···H − C noncovalent interaction. In this article, the structures and properties of novel heterogeneous layer‐layer carbon‐nanostructures involving π···H‐C‐C‐H···π···H‐C‐C‐H stacking based on [n ]‐graphane and [n ]‐graphene and their derivatives are theoretically investigated for n = 16–54 using dispersion corrected density functional theory B3LYP‐D3 method. Energy decomposition analysis shows that dispersion interaction is the most important for the stabilization of both double‐ and multi‐layer‐layer [n ]‐graphane@graphene. Binding energy between graphane and graphene sheets shows that there is a distinct additive nature of CH···π interaction. For comparison and simplicity, the concept of H‐H bond energy equivalent number of carbon atoms (noted as NHEQ), is used to describe the strength of these noncovalent interactions. The NHEQ of the graphene dimers, graphane dimers, and double‐layered graphane@graphene are 103, 143, and 110, indicating that the strength of C‐H···π interaction is close to that of π···π and much stronger than that of C‐H···H‐C in large size systems. Additionally, frontier molecular orbital, electron density difference and visualized noncovalent interaction regions are discussed for deeply understanding the nature of the C‐H···π stacking interaction in construction of heterogeneous layer‐layer graphane@graphene structures. We hope that the present study would be helpful for creations of new functional supramolecular materials based on graphane and graphene carbon nano‐structures. © 2017 Wiley Periodicals, Inc.     

Heterotricyclodecane IX. 2, 7-Dioxa-isotwistan, 2, 7-Dioxatwistan und 2, 8-Dioxa-homotwistbrendan sowie Derivate

The synthesis of 2, 7-dioxa-isotwistane ( 10 ), 2, 7-dioxa-twistane ( 17 ), and 2, 8-dioxa-homotwistbrendane ( 36 ) and several of their derivatives is described starting from endo-2-hydroxy-9-oxabicyclo[3.3.1]non-6-ene ( 1 ). The 10^O(7)-isotwistane iodide 7 and the corresponding tosylate 15 as well as the 10^O(2)-iodide 9 were treated under reaction conditions suitable for molecular rearrangements involving oxonium ions g and i , respectively, by neighbouring group participation leading to 2, 7-dioxa-twistanes and 2, 8-dioxa-homotwistbrendanes, respectively.     

Solvent Extraction Studies of Two Isomeric 5, 7, 7, 12, 12, 14-Hexamethy-1, 4, 8, 11-Tetraazacyclotetradecanes

The distribution ratios of two isomeric 5, 7, 7, 12, 12, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradecane, tet c and tet d, in several solvent systems at 25.0°C as functions of hydrogen ion concentration were determined. The protonation constants and the distribution constants of these macrocyclic ligands and their protonated species were obtained from the variations of the distribution ratios in the range of 6<–log [H⁺]<14.     

Aspergillus Protease-Catalyzed Esterification at pH > 7

Diverse N-substituted amino acids were converted to their corresponding esters by crude sucrose-immobilized Aspergillus oryzae protease in organic solvents at pH 7.5. The front part of captopril S-(-)-acetylthio-2-methylpropionic acid and the aspartame precursor Cbz-L-Asp-L-Phe-OH also underwent esterification under such conditions.     

Duplex Stability of 7-Deazapurine DNA: Oligonucleotides containing 7-bromo- or 7-iodo-7-deazaguanine

The oligonucleotide building blocks, the phosphonates 1a, b and the phosphoramidites 2a, b derived from 7-iodo- and 7-bromo-7-deaza-2′-deoxyguanosines 3a, b were prepared. They were employed in solid-phase oligonucleotide synthesis of the alternating octamers d(Br⁷c⁷G-C)₄ ( 8 ) and d(I⁷c⁷G-C)₄ ( 9 ) as well as the homo-oligonucleotides d[(Br⁷c⁷G)₅-G] ( 11 ) and d[(I⁷c⁷G)₅-G] ( 12 ). The melting profiles and CD spectra of oligonucleotide duplexes were measured. The T_m values as well as the thermodynamic data were determined and correlated to the major-groove modification of this DNA. The self-complementary octamers 8 and 9 form more stable duplexes compared to the parent oligomer d(G-C)₄. The heteroduplex of d[(I⁷c⁷G)₅-G] ( 12 ) with d(C₆) is slightly destabilized (ΔT_m = ?12°) over that of d[(c⁷G)₅-G] with d(C₆). However, the complex of 12 with poly(C) is more stable than that of d[(c⁷G₅-G)] with poly(C).     

Laser Raman studies on compounds 7.O4O.7 and 7.O5O.7

Laser Raman studies on two compounds of the α,ω-bis(4-alkylanilinebenzylidene -4′-oxy)alkane series were carried out in the spectral regions 1140–1220 and 1550–1650 cm^-1 as a function of temperature. Compounds 7.O4O.7 and 7.O5O.7, exhibit SmA and SmF phases. The structural differences between these liquid crystal dimers, having either an odd or an even number of carbon atoms in the spacer, are remarkably existent in the room temperature Raman spectra. The results are rationalized on the basis of the tendency of these compounds to exhibit bent shapes, and how this manifests in the odd-even effect at the molecular level assuming a semi-rigid core region of the dimeric molecule. It is found that the behaviour of the odd spacer dimer (7.O5O.7) agrees with the molecular model, whereas the even spacer dimer (7.O4O.7) behaves in a similar fashion to monomeric compounds such as the nO.m. compounds. In both cases, dynamic changes around the C=N bond have a profound effect both on the molecular shape in the different phases and on phase behaviour.     

Transition Metal Complexes with cyclo-Triphosphorus (η3-P3) and tetrahedro-Tetraphosphorus (η1-P4) Ligands

Salts of 3d, 4d, and 5d metals in the presence of the ligands 1,1,1,-tris(diphenylphosphinomethyl)ethane (triphos) or tris (2-diphenylphosphinoethyl) amine (np₃) react with white phosphorus P₄ (or yellow As₄) to produce several mononuclear sandwich and dinuclear triple-decker sandwich complexes, which contain the unprecedented cyclo-triphosphorus (or cyclo-triarsenic) unit acting as a trihapto-ligand. In these complexes the metal atoms are bonded to the there phosphorus atoms of the phosphane ligand and to the three atoms of the cyclo-P₃ or cyclo-As₃ unit. The complexes are diamagnetic or have μ_eff-values corresponding to one or two unpaired electrons. The cyclo-P₃ ligand is coordinatively unsaturated as proved by the fact that the mononuclear sandwich compounds may form Lewis-base adducts with electron-acceptor fragments. Reaction of the complexes (np)₃M (M = Ni, Pd) with white P₄ leads to formation of diamagnetic compounds [(np₃)M(η¹-P₄)], in which the metal atom is bonded to the three phosphorus atoms of the np₃-ligand and in addition to one P atom of the intact P₄ molecule, which behaves as a monohapto-ligand. This article contains a review of the syntheses and structures of these complexes as well as a unified, albeit qualitative, approach to their bonding and properties.     

Acylhydrazone Subunits as a Proton Cargo Delivery System in 7-Hydroxyquinoline

The reimagined concept of long-range tautomeric proton transfer using crane subunits is shown by designing and synthesising two new acylhydrazones containing a 7-hydroxyquinoline (7-OHQ) platform. The acylhydrazone subunits attached to the 7-OHQ at the 8th position act as crane arms for delivering proton cargo to the quinoline nitrogen. Light-induced tautomerization to their keto forms leads to Z/E isomerization of the C=C axle bond, followed by proton delivery to the quinoline nitrogen by the formation of covalent or hydrogen bonds. The axle‘s being either an imine or ketimine bond is the structural difference between the studied compounds. The −CH₃ group in the latter provides steric strain, resulting in different proton transport pathways. Both compounds show long thermal stability in the switched state, which creates a tuneable action of bidirectional proton cargo transport by using different wavelengths of irradiation. Upon the addition of acid, the quinoline nitrogen is protonated; this results in E/Z configuration switching of the acylhydrazone subunits. This was proven by single-crystal X-ray structure analysis and NMR spectroscopy.     

Indo-Mo Model with s·p Separation

A newly developed self-consistent-field molecular orbital theory is described and tested. The intermediate neglect of differential overlap (INDO) approximation is used, and all interaction integrals are differentiated according to their dependence upon 2s and 2p AO's. The bonding parameter β_l is reformulated so that the model is calibrated to only one specific molecular property, namely, the ionization energy of Hi. We expect that this model will not be biased toward any special families of molecules.     

Reactions of 2-Pyrones with 7-Aminoindazole: The First Synthesis of N-(1H-7-Indazolyl)-pyridinones

New N-(1H-7-indazolyl)-pyridinones have been prepared by the condensation of 2-pyrone derivatives with 7-aminoindazole in the presence of acid medium. They have been characterized by means of ¹H and ¹³C NMR, IR, and mass spectroscopy. The structure of the compounds and the mechanism of their formation are reported.     

Synthesis and structure determination of isomeric 7- and 8-chloro-1,5-benzodiazepine derivatives

Reaction of 4-chloro-1,2-benzenediamine with 3,3-dimercapto-1-phenyl-2-propen-1-one afforded, as expected, a mixture of 7-chloro and 8-chloro-1,3-dihydro-4-phenyl-2H-1,5-benzodiazepine-2-thione. After separation of the two components and further reaction, their structure was established by chemical degradation of 7-chloro-2-(2-diethylaminoethylthio)-4-phenyl-3H-1,5-benzodiazepine to 5-chloro-1,3-dihydro-1-methyl-2H-benzimidazol-2-one. The structure was also confirmed by single X-ray analysis of 7-chloro-2-(2-diethylaminoethylthio)-4-phenyl-3H-1,5-benzodiazepine.