The Conformation of 1,6-Diaza-2,7-cyclodecadione in Solution

From ¹H- and ¹³C-NMR. data, a crown conformation with trans amide bonds is deduced for 1,6-diaza-2,7-cyclodecadione ( 1 ) in solution. Compound 1 was obtained by reaction of 2-pyrrolidone with POCl₃.     

The synthesis and characterisation of some 2,7-diazaphenanthrene derivatives

2,7-Diazaphenanthrene was synthesised in moderate yield by the modified Pomeranz-Fritsch reaction by condensing diethoxyethanal with 1,4-benzenebismethanamine, followed by ring closure with 20% oleum, and its spectral characteristics recorded. A similar reaction with diethyl 1,4-benzenebis(3-aminopropanoate) gave either 2,7-diaza-1,8-dimethylphenanthrene or 2,7-diaza-1,8-phenanthrenebis(methylsulphonic acid), depending on the conditions of the ring closure reaction. The bis methiodides of these compounds were tested for phospholipase A₂ inhibitory action but were found to be inactive.     

Amination of octafluoronaphthalene in liquid ammonia: 2,6- and 2,7-Diaminohexafluoronaphthalenes selective preparation

Monoamination of octafluoronaphthalene by liquid ammonia affords 2-aminoheptafluoronaphthalene mainly (isolated yield 85-90%). Diamination of octafluoronaphthalene or amination of 2-aminoheptafluoronaphthalene affords a mixture of isomeric 1,6-, 1,7-, 2,6-, and 2,7-diaminohexafluoronaphthalenes with considerable prevalence of the 2,7-isomer (∼70%), thus being the first example of the predominant substitution at position 7 in 2-substituted polyfluoronaphthalenes. The 2,7/2,6 ratio of 2-X-heptafluoronaphthalene (X = ⁻NH, NH₂ and NHAc) amination diminishes with the decrease of electron-donating effect of the substituent; 2,7-diaminohexafluoronaphthalene forms in the reactions of 2-aminoheptafluoronaphthalene or octafluoronaphthalene with excess of NaNH₂ in liquid ammonia and 2,6-diaminohexafluoronaphthalene—in the reaction of 2-acetylamidoheptafluoronaphthalene with liquid ammonia followed by acetylamido group hydrolysis. The method of the selective preparation of these diamines based on the reversible transformation of amino group and a convenient technique of their high purity isolation by complexation with crown ether have been elaborated.     

Construction of dihydropyrimidine skeleton using 1,2,4-trisubstituted-1,3-diaza-1,3-butadienes

Construction of a dihydropyrimidine ring was developed that involved the cyclization of 1,3-diaza-1,3-butadienes having an N-protecting group (N-Cbz, N-Boc, N-alkyl, or N-benzyl) with α,β-unsaturated carbonyl compounds such as ethyl acrylate and p-chlorophenyl vinyl ketone. Consequently, 4-dimethylamino-2-phenyl-1,4,5,6-tetrahydropyrimidines were synthesized in good yields. Subsequently, the β-elimination of the dimethylamino group was carried out with MeI or SiO₂ to afford various N-protecting-2,5-disubstituted-1,6-dihydropyrimidines in good yields. Remarkably, the use of 4-chlorophenyl vinyl ketone directly provided the dihydropyrimidine without the tetrahydropyrimidine intermediate in excellent yield.     

Raman spectroscopic study of hydrogen bonding of N-alkyl-2-pyrrolidinones in heavy water

The Raman spectra of D₂O solutions of N-methyl-2-pyrrolidinone, N-ethyl-2-pyrrolidinone, and N-n-butyl-2-pyrrolidinone under diverse conditions were measured. Using a computer fitting of the band shape of the carbonyl stretching mode at various temperatures, an enthalpy difference for the inversion motion at the nitrogen atom due to hydrogen bonding with deuterium was estimated for these compounds. The enthalpy difference of hydrogen bond formation to the nitrogen atom of N-methyl-2-pyrrolidinone at 30 wt% in D₂O (mole fraction 0.080) was greater than that of N-methyl-2-pyrrolidinone in an aqueous solution at a mole fraction of 0.406. Furthermore, the enthalpy difference of N-alkyl-2-pyrrolidinones increased with the alkyl chain length. This is interepreted as a result of the change of the hydrophobic hydration of D₂O molecules around the solute molecules.     

Donor–acceptor alternating π‐conjugated polymers containing Di(thiophen‐2‐yl)pyrene and 2,5‐Bis(2‐octyldodecyl)pyrrolo[3,4‐c]pyrrole‐1,4(2H,5H)‐dione for organic thin‐film transistors

New diketopyrrolopyrrole (DPP)‐containing conjugated polymers such as poly(2,5‐bis(2‐octyldodecyl)‐3‐(5‐(pyren‐1‐yl)thiophen‐2‐yl)‐6‐(thiophen‐2‐yl)pyrrolo[3,4‐c]pyrrole‐1,4(2H,5H)‐dione) (P(DTDPP‐alt‐(1,6)PY)) and poly(2,5‐bis(2‐octyldodecyl)‐3‐(5‐(pyren‐2‐yl)thiophen‐2‐yl)‐6‐(thiophen‐2‐yl)pyrrolo[3,4‐c]pyrrole‐1,4(2H,5H)‐dione) (P(DTDPP‐alt‐(2,7)PY)) were successfully synthesized via Suzuki coupling reactions under Pd(0)‐catalyzed conditions. P(DTDPP‐alt‐(2,7)PY), incorporating 2,5‐bis(2‐octyldodecyl)‐3,6‐di(thiophen‐2‐yl)pyrrolo[3,4‐c]pyrrole‐1,4(2H,5H)‐dione (DTDPP) at the 2,7‐position of a pyrene ring showed a lower band‐gap energy (E. = 1.65 eV) than the 1,6‐substituted analog, P(DTDPP‐alt‐(1,6)PY) (E = 1.71 eV). The energies of the molecular frontier orbitals of the substituted polymers were successfully tuned by changing the anchoring position of DTDPP from the 1,6‐ to the 2,7‐position of the pyrene ring. An organic thin‐film transistor fabricated using the newly synthesized P(DTDPP‐alt‐(2,7)PY), as a semiconductor material exhibited a maximum mobility of up to 0.23 cm² V^?1 s^?1 (I_on/off ～ 10⁶), which was much larger than that obtained using P(DTDPP‐alt‐(1,6)PY). This distinction is attributed to morphological differences in the solid state arising from differences between the geometrical configurations of DTDPP and the pyrene ring. In addition, the organic phototransistor devices made of P(DTDPP‐alt‐(2,7)PY) showed interesting photoinduced enhancement of drain current when irradiating the excitation light whose intensity is very small. Based on the photoinduced effect on I_DS, photocontrolled memory could be realized under the variation of gate voltages. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Chirality due to deuterium substitution: synthesis and circular dichroism of (+)(R) p -2,7-dideuterio-1,6-methano[10]annulene

Summary The title compound was prepared from (–)(S) _p -2,7-dibromo-1,6-methano[10]annulene by treatment withn-Bu-Li and subsequent quenching with D₂O. The optical rotations at four wavelengths and the circular dichroism spectrum are reported.

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Chiralität durch Deuterium-Substitution: Synthese und Circulardichroismus von (+)(R) _p -2,7-Dideuterio-1,6-methano[10]annulen (Kurze Mitt.)

Zusammenfassung Die Titelverbindung wurde aus (–)(S) _p -2,7-Dibrom-1,6-methano[10]annulen durch Umsetzung mitn-Bu-Li und nachfolgende Reaktion mit D₂O dargestellt. Optische Rotationen bei vier Wellenlängen und das Circulardichroismus-Spektrum wurden bestimmt.

     

Synthesis of novel 2-phenyl-5-substituted dihydropyrimidines using 2-phenyl-1,3-diaza-1,3-butadienes and electron-deficient olefins

A novel synthetic method for 2,5-disubstituted dihydropyrimidines was developed. The cyclization of 1,3-diaza-4-dimethylamino-1,3-butadienes having a N-protecting group (N-Boc, N-Cbz, N-n-C₄H₉, N-Bn or N-Ph) with electron-deficient olefins, such as α,β-unsaturated carbonyl compounds, phenyl vinyl sulfone, and acrylonitrile was studied in detail. The cyclization smoothly proceeded to afford 4-dimethylamino-1,4,5,6-tetrahydropyrimidines or 1,6-dihydropyrimidines in good yields. The isolated 4-dimethylamino-1,4,5,6-tetrahydropyrimidines were converted to 2,5-disubstituted-1,6-dihydropyrimidines through the β-elimination of the dimethylamino group. 2,5-Disubstituted-1,4(6)-dihydropyrimidines were obtained after removal of the N-Boc or N-Cbz group. Independent tautomers of the resulting dihydropyrimidines were observed.     

Novel heterocyclic Tröger's base derivatives containing N-methylpyrrole units

Novel analogues of Tröger's base were prepared regioselectively from 4-amino-N-methylpyrrole carboxylates in good yield. Catalytic hydrogenation of dibenzyl-4,9-methano-1,6-dimethyl-4,5,9,10-tetrahydro-1H,6H-dipyrrolo-[3,2-b:3′,2′-f][1,5]diazocin-2,7-dicarboxylate 2b led to 4,9-methano-1,6-dimethyl-4,5,9,10-tetrahydro-1H,6H-dipyrrolo-[3,2-b:3′,2′-f][1,5]diazocin-2,7-dicarboxylic acid 3 which was used for the preparation of Tröger's base derivatives of natural antibiotics via an amide protocol. The novel heterocyclic Tröger's bases were characterized by a variety of spectroscopic techniques and compound 2b by X-ray crystallography. Incorporation of guanidine as the terminal group in the N-methylpyrrole Tröger's base skeleton opens the possibility for preparation of water soluble derivatives.     

Charge transfer complexes of N-substituted 2-pyrrolidinones

The complex formation of 1-ethyl-2-pyrrolidinone, 1-benzyl-2-pyrrolidinone and 1-phenyl-2-pyrrolidinone with iodine, iodine monobromide and iodine monochloride has been studied by u.v. and visible spectroscopic methods in carbon tetrachloride, dichloromethane, 1,2-dichloroethane, n-heptane and cyclohexane. The results show the equilibrium constants (K), complexation enthalpies (ΔH) and the wavelengths of maximum absorption bands (λ_max) of the complexes to vary markedly with the solvent. The decrease in the K values with increasing acceptor number (AN) of the solvent may be due to the competition of the solvent and the halogen molecule for the amide; for halogenated hydrocarbon solvents can act as weak electron acceptors. The complex formation ability of the electron donors decreases in the order 1-ethyl-2-pyrrolidinone ⪢ 1-benzyl-2-pyrrolidinone ⪢ 1-phenyl-2-pyrrolidinone, and the electron acceptor properties decrease in the order iodine monochloride ⪢ iodine monobromide ⪢ iodine.     

Structure of a dimeric piperidone-aldehyde condensation product

The base-catalyzed condensation of benzaldehyde with 1-methyl-4-piperidone (5) gave two isomeric products which were dimers of 3-benzylidene-1-methyl-4-piperidone (7). Reactions of the dimers and their mass spectral data are examined on the basis of the X-ray structural analysis of the dibromo derivative of the dimer which was identified as 4-p-bromobenzylidene-9-p-bromophenyl-10a-hydroxy-2,7-dimethyl-2,7-diaza-10-oxa-1,2,3,4,5,6,7,8,8a,10a,-decahydroanthracene (10b).     

Synthesis and chemical properties of silapiperazines and derivatives of 1,6-dioxa-3,8-diaza-5,10-disilacyclodecane-2,7-dione

The results of studies dealing with the synthesis of six- and ten-membered silicon-nitrogen-containing heterocyclic compounds are presented. The structures and reactivities of these compounds have been studied. High reactivities of 2,5-disilapiperazines and 1,6-dioxa-3,8-diaza-5,10-disilacyclodecane-2,7-dione derivatives have been noted. Possible schemes of the formation of these compounds are discussed.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2407–2414, October, 1996.     

The reaction of chloromethylsilanes with amines,hexamethyldisilazanes, and silylcarhamates

The reactions of chloromethylsilanes with amines, hexamethyldisilazane, and silylcarbamates were studied. The dependence of the composition and structure of the resulting products on the nature of the reagents used and reaction conditions was determined. A scheme for the synthesis of 4,9-diaza-2,7-dioxa-1,6-disilacyclodecane-3,8-dione derivatives was suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1798–1801, October, 1994.     

Synthesis,crystal structure,and fluorescence properties of several schiff-base compounds

Two new Schiff-base compounds, 1,6-bis(4-dimethylaminobenzyl)-2,5-diaza-1,5-hexadiene (bdh), 1,4-bis(4-dimethylaminobenzyl)-2,3-diaza-1,3-butadiene (bdb), and a silver complex of the latter ([Ag₂(bdb)₃(NO₃)₂]·H₂O, 1) have been synthesized and characterized. The crystal structure of complex 1 was determined. 1 is a dinuclear complex, with the silver ions lying in coordination tetrahedra formed by two nitrogen atoms from the bdb ligands and two oxygen atoms from the nitrate anions. The fluorescence properties of bdh and bdb were studied; the fluorescence of bdb was quenched by the addition of silver ions, indicating that it is a potential fluorescent reagent for the analysis of silver.     

Poly- und spirocyclische Silylhydrazone – Synthese und Molekülstrukturen

Poly- and Spirocyclic Silylhydrazones — Synthesis and Molecular Structures Bulky aminotrifluorosilanes react with lithiated dimethylketone-hydrazone to give 1,2-diaza-3-sila-5-cyclopentenes — DSCP — ( 1, 2 ). The 4-silylated ( 3–5, 8–15 ) and siloxysilyl-substituted ( 17, 18 ) rings eliminate no halosilane or siloxane thermally. Lithiated 2 dimerises with LiF elimination to give the (2+2)cycloadduct of a 1,2-diaza-3-sila-3,5-cyclopentadiene ( 6 ). Lithiated DSCP reacts with MeSiF₂N(CMe₃)SiMe₂CMe₃ via a nucleophilic 1,3-methanide ion migration to form LiF and the spirocyclic compound 18 . A compound with spirocyclic silicon ( 21 ) is formed in the reaction of bis(1,2-diaza-3-sila-5-cyclopenten-4-yl)difluorosilane ( 19 ) and the lithium salt of dimethyl-ketone-tert-butylhydrazone. The crystal structures of 6 and 21 are reported.     

Ionic organoboranes. Part 9. Ab initio molecular orbital study of energy, structure, and frontier orbitals of the isomeric [7.7.10]ousenes

We have used HF/3-21G(*) geometry optimization to determine the relative energies, structures, symmetries, and nature of frontier orbitals for the seven isomeric [7.7.10^x,y]ousenes in which two cationic tropyliumyl (C₇H₆⁺-) rings are substituted on the cage of the B₁₀H₁₀²⁻ anion. The x,y=(2,7) isomer is the most stable. Energetically the remaining fall into two groups: (1,10), (2,4), and (1,6) which differ from (2,7) by less than 2 kcal mol⁻¹, and (2,6),(2,3), and (1,2) which differ by about 10 kcal mol⁻¹. The lower stability of the latter group is attributed to repulsive interactions between substituent rings rather than electronic effects. Three ousenes (1,2), (1,10), and (2,3) have lower symmetry than expected for a simple disubstituted B₁₀H₁₀²⁻ cage as a result of steric effects. Examination of frontier orbitals demonstrates that all seven species should show charge transfer excitations from cage to both rings similar to that previously experimentally observed for the [7.10²] hemiousenide ion.     

Reactions of 2-(perfluoroalkyl)ethane thiols with 1,6-heptadiene and 4-substituted 1,6-heptadienes: the synthesis of RFethanethio-cyclopentanoic and -dioic acids; and, “geminal-twin-tail” bis-(perfluoroalkylethanethio)alkanoic acids

Kinetic analysis of the free radical addition of n-C₆F₁₃I to 1,6-heptadiene gives a rate ratio of cyclization to addition (k_d1/k_c) of 0.568 at 70 °C; thus, the rate of cyclization (k_c) is twice that of iodine transfer (k_d1). By contrast, for n-C₆F₁₃CH₂CH₂SH (k_d1/k_c) = 14.4 at 70 °C, and radical transfer of H from the thiol is 14.4 times the faster than cyclization. Substitution at the center of 1,6-heptadiene has a profound effect on the linear/cyclic adduct ratio. For the addition of n-C₃F₇I (R_FI:diene=2:0) the adduct ratios dramatically decrease in the order: 1,6-heptadiene (1.17) > 4-carboxy-1,6-heptadiene (0.0613) > 4,4-bis-ethoxycarbonyl-1,6-heptadiene (<0.001). Bis-addition to the 4,4-substituted dienes is strongly disfavored, and the desired “geminal-twin-tail” [R_F(CH₂)₃]₂CHCO₂R, or [R_F(CH₂)₃]₂C(CO₂R)₂ must be synthesized by other means. For the reaction of R_FCH₂CH₂SH with the dienes (1:1), the respective adduct ratios are 11.3 (n-C₆F₁₃), 0.370 (n-C₈F₁₇), and 0.0716 (n-C₆F₁₃). However, adding the 4-carboxy-1,6-heptadiene slowly to four mols of n-C₈F₁₇CH₂CH₂SH yields 98% of the geminal bis-adduct [R_FCH₂CH₂S(CH₂)₃]₂CHCO₂H, which is a new, fluorophilic, geminal-twin-tail acid.     

Mercury(II) iodide coordination polymers generated from polyimine ligands

A series of new HgI₂ organic polymeric complexes, [Hg₂(L1)I₄]_n (1), [Hg(L2)I₂]_n (2), [Hg(L3)I₂]_n (3), [Hg₂(L4)I₄]_n (4), [Hg(L5)I₂]_n (5), [Hg(L6)I₃](HL6) (6) {L1 = 1,4-bis(2-pyridyl)-2,3-diaza-1,3-butadiene, L2 = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, L3 = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, L4 = 2,5-bis(2-pyridyl)-3,4-diaza-2,4-hexadiene, L5 = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene and L6 = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene} was prepared from reactions of mercury(II) iodide with six organic nitrogen donor-based ligands under thermal gradient conditions using the branched tube method. All these compounds were structurally characterized by single-crystal X-ray diffraction. The HgI₂ coordination polymers obtained with the ligands L2, L3 and L5 show one-dimensional zig-zag motifs and in these compounds the HgI₂ units are connected to each other by the ligands L2, L3 and L5 through the pyridyl nitrogen atoms. The L1 and L4 ligands in the compounds 1 and 4 act as both a chelating and bridging group. In the compound 6 the ligand L6 acts as a monodentate ligand, resulting form a discrete compound. The thermal stabilities of compounds 1–6 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA).     

2,2-Difluor-1,2,3-trimethyl-1,3-diaza-2λ5-phospholidin

2,2-Difluoro-1,2,3-trimethyl-1,3-diaza-2λ⁵-phospholidine The title compound 1 is obtained in about 50% yield by oxidative fluorination of 1,2,3-trimethyl-1,3-diaza-2λ³-phospholidine, 6 , with IF₅. 1 is characterized by its nmr, mass, and ir spectra.     

Yb(OTf)3-Catalyzed 1,3-dipolar cycloaddition of nitrone with alkene; Switch in diastereoselectivity by solvent and bidentate auxiliary

Yb(OTf)₃ (ytterbium trifluoromethanesulfonate)-catalyzed diastereoselective 1,3-dipolar cycloaddition of a nitrone with α,β-unsaturated carbonyl compounds was studied. While endo-cycloadduct was obtained from the reaction of C, N-diphenylnitrone with N-crotonoyl-oxazolidinone or N-crotonyl-2-pyrrolidinone in toluene, exo-adduct was predominant in acetonitrile. The enones carrying imidazolidinone or succinimide ring reacted with the nitrone to give the exo-adducts primarily in both solvents.