Synthesis and structures of 4,5-dimethyl-1,3-bis(pyridin-2-ylmethyl)-1H-imidazolium chloride and 1,1′-bis(pyridin-2-ylmethyl)-2,2′-bis(4,5-dimethylimidazole)

4,5-Dimethyl-1,3-bis(pyridin-2-ylmethyl)-1H-imidazolium chloride (1) was synthesized and characterized by IR and NMR spectroscopy and X-ray diffraction. An attempt to prepare the free tridentate N-heterocyclic carbene pincer ligand by the reaction of 1 with KN(SiMe₃)₂ resulted in the formation of 1,1′-bis(pyridin-2-ylmethyl)-2,2′-bis(4,5-dimethylimidazole) as a product of dimerization of the target carbene followed by the rearrangement accompanied by the elimination of dipyridylethane.

     

Metal derivatives of 1,3-bis(2-pyridyl)-1,3-propanedione and N,N′-dimethyl-1,3-bis(2-pyridyl)-1,3-propanedione

Complexes of transition metal ions with the oxygen-nitrogen containing ligand 1,3-bis(2-pyridyl)-1,3-propanedione (bpypH) have been synthesized. These present stoichiometries which do not conform with the usual tendency manifested by β-diketones, since molecular formulas with the composition M(bpyp)X are found. A nitrogen methylated ligand N,N′-dimethyl-1,3-bis(2-pyridyl)-1,3-propanedione methyl sulphate [dimebpypH] (MeSO₄)₂ has also been synthesized and its complexes with transition metal ions studied. The stoichiometries now, resemble those of typical β-diketones, namely [dimepyp]₂MX₄ with four anions because of the dicationic nature of the original ligand. This, together with IR evidence suggests a dual type of coordination by bpip via the β-diketone and the pyridyl moieties.     

Convenient synthesis of mono- and di-β-hydroxy-β-bis(trifluoromethyl)-(di)imines from β-hydroxy-β-bis(trifluoromethyl)-ketones and (di)amines

A series of novel β-hydroxy-β-bis(trifluoromethyl)-imines (2a-j) and di(β-hydroxy-β-bis(trifluoromethyl))-diimines (3a-f) were prepared in moderate to good yields via a simple two-step approach: first, β-hydroxy-β-bis(trifluoromethyl)-ketones (1a-c) were obtained by a catalyst-free aldol reaction between liquid hexafluoroacetone sesquihydrate and ketones (acetone, acetophenone, and pinacolone, respectively); then, condensation of the latter fluorinated β-ketols 1a-c with primary amines or diamines was achieved in the presence of Lewis (montmorillonite, InBr₃, La(OTf)₃) or Brönsted (PTSA) acid catalysts. The molecular structures of mono- and di-β-hydroxy-β-bis(trifluoromethyl)-(di)imines 2e,h and 3a,f were determined and found to exhibit strong intramolecular (R)N?H-O hydrogen bonding.     

Polymerization of higher α-olefins with the catalytic system (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-bis(perfluorophenyldimethanolate) titanium(IV) dichloride-organoaluminum compound

The catalytic activity of the titanium(IV) dichloride complex with the (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-bis(perfluorophenyldimethanol) ligand in the presence of a cocatalyst (polymethylaluminoxane, triethylaluminum, or triisobutylaluminum) in the polymerization of higher α-olefins (1-hexene, 1-octene, 1-decene) is investigated. It is shown that, depending on the types of cocatalyst and monomer and the molar ratio of components of the catalytic system, high- or ultrahigh-molecular-mass poly(α-olefins) with M _w = (4 × 10⁵)?(3 × 10⁶) can be prepared. The chain microstructure of polyhexene is examined.     

A novel bifunctional reagent: 2,2′-bis(methoxymethylene)- 2,2′-sulfonyldiacetonitrile

Preparation properties and reactions of the title reagent are reported. The reagent is potentially useful for cross-linking proteins and/or nucleic acids.     

Formation of 2,2-difluoro-3-hydroxymethylbenzo-1,4-oxathianes from 2-(α-trifluoromethylvinylthio)phenols)

It is shown that 2,2-difluoro-3-hydroxymethylbenzo-1,4-oxathianes are formed together with 3-trifluoromethylbenzo-1,4-oxathianes whenortho-(-trifluoromethyl--chloroethylthio)phenols are boiled with excess aqueous alkali. The mechanism of the reaction is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1457–1459, August, 1994.     

STRUCTURE OF 1,3-BIS(DIPHENYLHYDROXYSILYL)-2,2-DIMETHYL-4,4-DIPHENYL-CYCLODISILAZANE

<正> M =667.0, monoclinic, P21/n, a=11.854(2), b=10.136(1), c=29.931(4) A, β=93.51(1)°, Z=4, V=3588.9(8)A3, Dx=1.23 Mgm-3, λ(MoKα)=0.71069A, μ(Mo-Kα)=2.0, F(000)=1408, room temperature, R=0.072 for 3015 reflections. The structure was solved by direct method.The cyclodisilazane ring is a flattened tetrahedron. The three bonds on N(1) and N(2), respectively, are in a plane. The mean bond lengths of Si-C (methyl), Si-C(phenyl), Si-O, Si-N(endocyclic) and Si-N(exo-) are 1.839, 1.847, 1.636, 1.744 and 1.711A, respectively.     

Synthesis and Structure of a Novel Ion-pair Palladium(Ⅱ) Compound Containing 2-Thioxo-1,3-dithiole-4,5-bis(thiolate)

A novel ion-pair palladium(Ⅱ) compound,(NO2BzPy)2[Pd(dmit)2](NO2BzPy+ = 1-(4-nitrobenzyl)pyridinium,dmit2-= 2-thioxo-1,3-dithiole-4,5-bis(thiolate)),was synthesized and characterized by single-crystal X-ray structure determination.This compound crystallizes in the monoclinic system,space group P21/n with a = 10.4463(11),b = 8.5627(9),c = 20.017(2) ,β = 97.7730(10)°,V = 1774.1(3) 3,Z = 2,C30H22N4O4S10Pd,Mr = 929.52,Dc = 1.740 g/cm3,μ = 1.155 mm-1,S = 1.006,F(000) = 936,R = 0.0354 and wR = 0.0675.The most intriguing general structural feature of the compound is the completely segregated columnar stacks of anions and cations.There exist hydrogen-bonding interactions within the cation column.     

Structuresof 2,2′-bis(dimethylamino)biphenyl and its monohydrobromide)

In the context of ‘proton sponge’ systems, for the conformationally flexible biphenyl 1 the X-ray structure analysis as well as the basicity have been determined. 1 forms monoprotonated salts of which the structure of the hydrobromide 1a·BrX was solved. It contains a ‘proton sponge’-like N⋯H⋯N hydrogen bridge to which the 1000-fold increase of the basicity constant as compared to N,N-dimethylaniline is attributed.     

Synthesis of (−)-(4R,5R)-4,5-bis[di-3′-(2′,6′-dimethoxypyridyl)phosphinomethyl]-2,2-dimethyl-1,3-dioxolane and its application in the Rh-catalyzed asymmetric hydrogenation reactions

The chiral ligand (−)-(4R,5R)-4,5-bis[di-3′-(2′,6′-dimethoxypyridyl)phosphinomethyl]-2,2-dimethyl-1,3-dioxolane 3 [(R,R)-Py*-DIOP] was synthesized via a key intermediate bis[3-(2,6-dimethoxypyridyl)]phosphine-borane 9. The asymmetric hydrogenation of prochiral olefins was investigated using a rhodium catalyst containing 3. For the hydrogenation of amidoacrylic acids, enols and itaconic acid, while the enantioselectivity of [Rh-(R,R)-Py*-DIOP] was similar to that of [Rh-(R,R)-DIOP] the absolute configurations of the products from the two catalyst systems were found to be opposite.     

Preparation of 1,1′-Oxy-bis(3,3-bis(trifluoromethyl)-3(1H)-1,2-benziodoxole) and 2-(N-(p-Toluenesulfonyl)imino)iodobenzylmethyl Ether

Conditions for improved preparation of the crystalline iodine(III) reagents [1,2-C₆H₄(C(CF₃)₂OI)]₂O and 1,2-C₆H₄(CH₂OMe)(I=NTs) are presented together with their x-ray structures. The former is prepared by hydrolysis of 1,2-C₆H₄(C(CF₃)₂OICl (x-ray) and allows the preparation of cyclic sulfates from alkenes; the latter fashions sulfamidate under related conditions.     

1,1-Bis(trifluoromethyl)butadiene-1,3—A new fluorinated building block

Although 1,1-bis(trifluoromethyl)butadiene-1,3 (1) reacts with dimethylamine with selective formation of 1,4-adduct [trans-(CF₃)₂CHCHCHCH₂N(CH₃)₂], halogenation of 1 proceeds with predominant formation (>92%) of 1,2-adducts (CF₃)₂CCHCHXCH₂X (X = Cl or Br). Electrophilic conjugated addition of “ClF” or “BrF” to 1 proceeds exclusively with the formation of 1,2-adducts (CF₃)₂CCHCHFCH₂X (major) and (CF₃)₂CCHCHXCH₂F (X = Cl or Br). Difluorocarbene adds selectively to CHCH₂ moiety of 1 forming thermally stable vinylcyclopropane. In Diels-Alder reaction with linear or cyclic dienes (butadienes, cyclopentadiene, cyclohexadiene-1,3) and quadricyclane compound 1 behaves as dienophile providing for the reaction electron-deficient CHCH₂ bond. The relative rate of cycloaddition of 1 and other fluoroolefins to quadricyclane, measured by high temperature NMR, indicates that (CF₃)₂CCH acts as very strong electron-withdrawing substituent. Synthetic utility of products based on 1 was also demonstrated.     

Synthesis and applications of (R)- and (S)-7,7′-dimethoxy-2,2′-bis(diphenylphosphino)-1,1′-binaphthalene

The synthesis of (R)- and (S)-7,7′-dimethoxy-2,2′-bis(diphenylphosphino)-1,1′-binaphthalene 5a and 5b is described. The phosphorus atoms in (S)-(−)-5b are shown to be slightly more basic than the phosphorus atoms in (S)-BINAP by comparing the magnitude of the ¹J (³¹P–⁷⁷Se) coupling constant in their respective diselenide derivatives. (S)-(−)-5b behaved similarly to (S)-BINAP in asymmetric Heck reactions.     

Reactions of 1,3-bis(ω-bromoalkyl)-6-methyluracils with 2-(dialkylamino)ethylphosphonates and 2-(dialkylamino)ethyl phosphates

1,3-Bis(4-bromobutyl)-6-methyluracil reacts with diethyl 2-(dimethylamino)ethylphosphonate to form a bisquaternary ammonium salt, whereas the reaction of 1,3-bis-(6-bromohexyl)-6-methyluracil with diethyl 2-(diethylamino)ethyl phosphate gives 1,3-bis-[(6-diethoxyphosphoryloxy)hexyl]-6-methyluracil and 1,1,4,4-tetraethylpiperazinium dibromide. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1130–1132, June, 2000.     

S- and N-alkylation of 2,2′-(alkane-α,ω-diyldisulfanediyl)-bis(1,3-benzothiazoles) with 1-iodopropan-2-one in the presence of iodine

Russian Journal of Organic Chemistry - The alkylation of 2,2′-(methylenedisulfanediyl)- and 2,2′-(ethane-1,2-diyldisulfanediyl)bis-(1,3-benzothiazoles) with 1-iodopropan-2-one involves...     

Convenient synthesis of （4R,5R）-4,5-bis（aminomethyl）-2-isopropyl- 1,3-dioxolane

A convenient approach for the preparation of (4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane is described. The target compound via two steps is synthesized from diethyl-2,3-O-isobutylidene-D-tartrate, through ammonolysis and reduction.     

Bidimensional chronoabsorptometric study of electropolymerisation of 4,4′-bis(2-methylbutylthio)-2,2′-bithiophene

Bidimensional chronoabsorptometry is a novel spectroelectrochemical technique that monitors simultaneously three different signals: current and absorbance both normal to the electrode plane and parallel to this plane during a time in which a fixed potential is imposed. This technique is applied in the visible range to the study of the electropolymerisation of 4,4^′-bis(2-methylbutylthio)- 2,2^′-bithiophene (MBTBT). Experiments are performed in a spectroelectrochemical cell under finite diffusion conditions (thin layer cell) with the aim of interpreting the processes taking place both at the electrode surface and in the adjacent solution during the potentiostatic electrogeneration and deposition of the polymer. Correlations are drawn out among the trends of the oligomers concentration in solution, the polymer electrodeposition and charging, and the current flow, on the time scales of the different steps of the process.     

Bis{(μ-acetato)[μ-bis(salicylidene)-1,3-propanediaminato]zinc(II)}zinc(II)

In the title linear trinuclear compound, [Zn{Zn(CH₃COO)(C₁₇H₁₆N₂O₂)}₂], the central Zn²⁺ ion, which is located on an inversion centre, has a distorted octahedral coordination involving four bridging O atoms from two N,N′-bis­(salicyl­idene)-1,3-propane­diaminate ligands in the equatorial plane and one O atom from each bridging acetate group in the axial positions. The coordination around the terminal Zn²⁺ ion is irregular square pyramidal, with two O and two N atoms of the ligand in the basal plane and one O atom from an acetate group in the apical position. The acetate bridges linking the central and terminal Zn²⁺ ions are mutually trans. The Zn⃛Zn distance is 3.0520 (8) Å. The relationship of this structure to that of [Zn{Cu(CH₃COO)(C₁₇H₁₆N₂O₂)}₂] is discussed.