Synthesis,Crystal Structure,and Thermal Behaviors of 3‐Nitro‐1,5‐bis(4,4′‐dimethylazide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP)

The energetic material, 3‐nitro‐1,5‐bis(4,4′‐dimethyl azide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP), was firstly synthesized by means of Click Chemistry using 1,5‐diazido‐3‐nitrazapentane as main material. The structure of NDTAP was confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy; mass spectrometry, and elemental analysis. The crystal structure of NDTAP was determined by X‐ray diffraction. It belongs to monoclinic system, space group C2/c with crystal parameters a=1.7285(8) nm, b=0.6061(3) nm, c=1.6712(8) nm, β=104.846(8)°, V=1.6924(13) nm³, Z=8, μ=0.109 mm⁻¹, F(000)=752, and D_c=1.422 g cm⁻³. The thermal behavior and non‐isothermal decomposition kinetics of NDTAP were studied with DSC and TG‐DTG methods. The self‐accelerating decomposition temperature and critical temperature of thermal explosion are 195.5 and 208.2 °C, respectively. NDTAP presents good thermal stability and is insensitive.     

Studies on Electrophilic Interaction of 2,3‐Allenols with Electrophilic Halogen Reagents: Selective Synthesis of 2,5‐Dihydrofurans, 3‐Halo‐3‐alkenals,or 2‐Halo‐2‐alkenyl Ketones

The reaction of primary 2,3‐allenols with iodine (I₂) afforded 2,5‐dihydrofurans while that of readily available 1‐aryl or 1‐methyl substituted 2,3‐allenols with bromine (Br₂), N‐bromosuccinimide (NBS), I₂ or N‐iodosuccinimide (NIS) formed the not easily available but synthetically useful 3‐halo‐3‐alkenals and 2‐halo‐2‐alkenyl ketones with good selectivity and yields via a sequential electrophilic interaction of X⁺ with the allene moiety, 1,2‐aryl or 1,2‐proton shift, and H⁺ elimination process.     

Transition Metal‐Catalyzed Synthesis of (E)‐2‐(Alkylthio)alka‐1,3‐dienes from Allenes and Dialkyl Disulfides with Concomitant Hydride Transfer

Reaction of dialkyl disulfides or diselenides with allenes is catalyzed by a rhodium‐phosphine complex and trifluoromethanesulfonic acid giving (E)‐2‐alkylthio(seleno)‐1,3‐dienes and (E)‐2‐alkylthio(seleno)‐2‐alkenes. Unlike the reaction of alkynes, the reaction of allene is accompanied by hydride transfer.     

Asymmetric 1,4‐Addition of Diethylzinc to Cyclic Enones Catalyzed by Cu(I)‐Chiral Sulfonamide‐Thiophosphoramide Ligands and Lithium Salts

The chiral sulfonamide‐thiophosphoramide ligand L1 , prepared from the reaction of (1R,2R)‐(−)‐1,2‐cyclohexanediamine with diphenylthiophosphoryl chloride and p‐toluenesulfonyl chloride, was used as a chiral ligand in Cu(MeCN)₄ClO₄‐promoted catalytic asymmetric addition of diethylzinc to cyclic enones using LiCl as an additive in which up to 90% ee can be realized under mild conditions within 0.5 h. This chiral ligand is stable and recoverable after usual work‐up and can be reused in the same catalytic asymmetric reaction. Moreover, it was found that this series of chiral ligands represents a type of S,O‐bidentate ligands on the basis of ¹H NMR, ³¹P NMR and ¹³C NMR spectroscopic investigations. The linear effect of ligand ee and product ee further revealed that the active species is a monomeric Cu(I) complex bearing a single ligand.     

Preparation and fluorescence properties of poly(o‐methyl‐acrylamideyl‐benzoic acid)‐ZnS composites

Poly(o‐methyl‐acrylamideyl‐benzoic acid)‐ZnS (P(o‐MAABA)‐ZnS) nanocomposites have been prepared and characterized. The resultant P(o‐MAABA)‐ZnS nanocomposites in solution show two emissions in the purple‐light area (370 nm) and in the blue‐light area (425 nm), which are assigned to the polymer and ZnS nanoparticles, respectively. The coordination between the polymer and Zn²⁺ and the surface chemical composition has been studied by Infrared spectroscopy and X‐ray photoelectron spectroscopy (XPS). The particle size of ZnS nanoparticles was homogeneous and the average size was 3.8 nm, which were characterized by UV absorption spectrum and X‐ray Diffraction. The P(o‐MAABA)‐ZnS composites displays good film formability and the films also show two emissions in 370 and 425 nm. After doped with Tb³⁺, there was effective energy transfer from ZnS nanoparticles to Tb³⁺. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Iron‐Catalyzed Regio‐ and Stereoselective Conjugate Addition of Aryl‐Grignard Reagents to α,β,γ,δ‐Unsaturated Sulfones and its Synthetic Application

The iron‐catalyzed δ‐addition of aryl‐Grignard reagents to α,β,γ,δ‐unsaturated sulfones proceeded in a regio‐ and stereoselective manner to give cis‐4‐aryl‐2‐alkenyl sulfones. Allylic alkylation of the resultant products was performed without isomerization of the cis‐olefin to give cis‐4‐aryl‐1,1‐dialkyl‐2‐alkenyl sulfones, which upon intramolecular Friedel–Crafts reaction with aluminum chloride gave 1,4‐dihydronaphthalenes having a quaternary carbon center.     

Ultrasound‐accelerated dehydrogenation of poly(1,3‐cyclohexadiene): efficient synthesis of poly(para‐phenylene)

The effect of ultrasonication on the dehydrogenation of poly(1,3‐cyclohexadiene) (PCHD) with benzoquinones was examined with the aim of improving the rate of reaction at moderate temperature. The type of solvent and the ultrasound treatment strongly affected the dehydrogenation of PCHD. The rate of reaction of the dehydrogenation of PCHD with 2,3‐dichloro‐5, 6‐dicyano‐1,4‐benzoquinone (DDQ) or 3,4,5,6‐tetrachloro‐1,2‐(o)‐benzoquinone (TOQ) was markedly improved by the use of ultrasound, and poly(para‐phenylene) (PPP) and PPP–TOQ complex, respectively, were successfully obtained. The electron drift mobility for PPP was of the order of 10^?4 cm² V^?1 s^?1 with a negative slope, while that for PPP–TOQ complex was of the order of 10^?3 to 10^?4 cm² V^?1 s^?1 with a negative slope. The dehydrogenation of PCHD with benzoquinones under ultrasonication is thus an effective method to obtain soluble PPP with a well‐defined polymer chain structure. Copyright © 2010 Society of Chemical Industry     

Palladium‐Catalyzed Two‐Component Domino Coupling Reaction of (Z)‐β‐Bromostyrenes with Norbornenes: Synthesis of 1,5‐Enynes

Polyfunctional molecules, 1,5‐enynes, have been achieved via a palladium(0)‐catalyzed domino coupling reaction of (Z)‐β‐bromostyrenes with norbornenes in the presence of cesium carbonate and N,N‐dimethylformamide. The process involves a double Heck‐type procedure, two‐fold C(sp²) H activation and formation of two carbon‐carbon bonds. There are possibilities of diversified transformation for the domino coupling of (Z)‐β‐bromostyrenes with norbornenes, the procedure is successfully driven to 1,5‐enynes via accurate adjustment of the reaction conditions.

     

Electropreparation of (±)‐10‐camphorsulfonate‐doped poly(o‐phenylenediamine) in acetonitrile and its use in determination of glucose

Poly(o‐phenylenediamine) (PoPD) film has been electrochemically prepared on Pt electrode in an acetonitrile–water medium containing o‐phenylenediamine (oPD) monomer and (±)‐10‐camphorsulfonic acid (HCSA) by using the cyclic voltammetry (CV). The PoPD film (PoPD–CSA) has been characterized by FTIR, CV, EIS, FESEM, and conductivity measurement. The glucose biosensor (Pt/PoPD–CSA/GOx) has been prepared from the PoPD coated electrode by immobilizing glucose oxidase (GOx) enzyme using glutaraldehyde. The biosensor shows a low detection limit and wide linear working range, a good reusability, long‐term stability, and anti‐interference ability. The Pt/PoPD–CSA/GOx has possesses higher sensitivity (2.05 μA/mmol L^?1) and affinity to glucose due to the use of CSA ion as dopant. The linear concentration ranges of Pt/PoPD–CSA/GOx have been found to be 9.6 × 10^?3 to 8.2 mmol L^?1 from calibration curve and 4.6 × 10^?2 to 100 mmol L^?1 from the relationship between the (1/glucose concentration) and (1/current difference). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39864.     

Cinchona Alkaloid‐Catalyzed Enantioselective Amination of α,β‐Unsaturated Ketones: An Asymmetric Approach to Δ2‐Pyrazolines

Δ²‐Pyrazolines are of significant medicinal and synthetic interest due to their therapeutic properties and utility in the synthesis of 1,3‐diamines, yet few asymmetric methods exist to prepare them. An unprecedented and highly enantioselective organocatalytic synthesis of 2‐pyrazolines was achieved through an asymmetric conjugate addition catalyzed by 9‐epi‐amino Cinchona alkaloids followed by deprotection‐cyclization, which furnished chiral 2‐pyrazolines in 46–78% yield and 59–91% ee. This bifunctional catalytic methodology thus provides easy access to a considerable range of optically active 3,5‐dialkyl 2‐pyrazolines.     

Study on the Azido‐Tetrazolo Tautomerizations of 3,6‐Bis(azido)‐1,2,4,5‐tetrazine

The azido‐tetrazolo tautomerizations of 3,6‐diazido‐1,2,4,5‐tetrazine (DIAT) in different solvents were investigated with HPLC and ¹³C NMR spectroscopy. 6‐Amino‐tetrazolo[1,5‐b]‐1,2,4,5‐tetrazine (ATTZ) was irreversibly formed as the final product by azido‐cyclization following N₂ elimination from one of the azido substituents at room temperature in DMSO. The structure of ATTZ was characterized by X‐ray crystallography; differential scanning calorimetry (DSC), mass spectrometry, as well as IR and ¹H NMR and ¹³C NMR spectroscopy. The crystal density was found to be 1.272 g cm⁻³. DSC result suggested that ATTZ with the melting point of 84 °C strongly decomposes with explosion at 198 °C, which can be regarded as a primary explosive.     

Zinc‐Catalyzed Tandem Diels–Alder Reactions of Enynals with Alkenes: Generation and Trapping of Cyclic o‐Quinodimethanes (o‐QDMs)

A systematic investigation of ZnCl₂‐catalyzed reactions of enynals with alkenes has been undertaken. Structurally unique propeller‐like products could be obtained under mild conditions. Cyclic o‐quinodimethanes (o‐QDMs) are generated through [4+2] cycloaddition between enynals and alkenes. Both electron‐poor and electron‐rich dienophiles could be used to trap the active intermediate through [4+2] cycloaddition. But [1,5]‐H shift products could also be observed when electron‐rich alkenes were used as dienophile. DFT calculations were performed to understand the reaction mechanism. A competition between the [4+2] cycloaddition and [1,5]‐H shift was proposed for the transformation of cyclic o‐QDMs. The selectivity could be affected by the properties of the substrates.

     

Synthesis,cationic polymerization and curing reaction with epoxy resin of 3,9‐di(p‐methoxybenzyl)‐1,5,7,11‐tetra‐oxaspiro(5,5)undecane

A new spiro ortho carbonate, 3,9‐di(p‐methoxybenzyl)‐1,5,7,11‐tetra‐oxaspiro(5,5)undecane was prepared by the reaction of 2‐methoxybenzyl‐1,3‐propanediol with di(n‐butyl)tin oxide, following with carbon disulfide. Its cationic polymerization was carried out in dichloromethane using BF₃‐OEt₂ as catalyst. The [¹H], [¹³C]NMR and IR data as well as elementary analysis of the polymers obtained indicated that it underwent double ring‐opening polymerization. The polymerization mechanism is discussed. The curing reaction of bisphenol A type epoxy resin in the presence of the monomer and a curing agent was investigated. DSC measurements were used to follow the curing process. In the case of boron trifluoride‐o‐phenylenediamine (BF₃‐OPDA) as curing agent, two peaks were found on the DSC curves, one of which was attributed to the polymerization of the epoxy group, and the other to the copolymerization of the monomer with the isolated epoxy groups or homopolymerization. However, when BF₃‐H₂NEt was used as curing agent, only one peak was present. IR measurement of the modified epoxy resin with various weight ratios of epoxy resin/monomer was performed in the presence of BF₃‐H₂NEt as curing agent. The results demonstrate that the conversion of epoxy group increases as the content of monomer increases. The curing process and the structure of the epoxy resin network are discussed. © 2000 Society of Chemical Industry     

Electrophilic Addition of Allylic Carbocations to 2‐Cyclopropylidene‐2‐arylethanols: A Strategy to 3‐Oxabicyclo[3.2.0]heptanes

We have developed an electrophilic addition of allylic carbocations to 2‐cyclopropylidene‐2‐arylethanols constructing carbon‐carbon bonds with excellent regio‐ and stereoselectivities. The reaction affords 3‐oxabicyclo[3.2.0]heptanes in moderate to good yields via the electrophilic addition/ring‐opening/vinyl group shift/intramolecular cyclization sequence.

     

Microwave‐assisted polycondensation of 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L‐leucine) diacid chloride with aromatic diols

A new facile and rapid polycondensation reaction of 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L ‐leucine) diacid chloride (1) with several aromatic diols such as phenol phthalein (2a), bis phenol‐A (2b), 4,4′‐hydroquinone (2c), 1,4‐dihydroxyanthraquinone (2d), 1,8‐dihydroxyanthraquinone (2e), 1,5‐dihydroxy naphthalene (2f), dihydroxy biphenyl (2g), and 2,4‐dihydroxyacetophenone (2h) was performed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o‐cresol. The polymerization reactions proceeded rapidly, compared with the conventional solution polycondensation, and was completed within 10 min, producing a series of optically active poly(ester‐imide)s with quantitative yield and high inherent viscosity of 0.50–1.12 dL/g. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of this optically active poly(ester‐imide)s are reported. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3003–3009, 2000     

Spiro‐Pyrrolidine‐Catalyzed Asymmetric Conjugate Addition of Hydroxylamine to Enals and 2,4‐Dienals

A spiro‐pyrrolidine‐catalyzed tandem aza‐1,4‐addition/hemi‐acetalization reaction was developed with excellent enantioselectivity (12 examples of ≥99% ee), and several substrates proceeded with higher ee (up to 10% increase) compared with the literature data. Particularly, an interesting and unusual aza‐1,6‐/oxa‐1,4‐addition for some substrates was also observed.

     

Superbase‐Catalyzed [4+2] Cycloaddition of Acetylenes to 3,6‐Di(pyrrol‐2‐yl)‐1,2,4,5‐tetrazine: A Facile Synthesis of 3,6‐Di(pyrrol‐2‐yl)pyridazines

Acetylenes undergo the [4+2] cycloaddition to 3,6‐di(pyrrol‐2‐yl)‐1,2,4,5‐tetrazine in the potassium hydroxide/dimethyl sulfoxide or potassium tert‐butoxide/dimethyl sulfoxide systems (80 °C, 2.5–4 h) to afford (after extrusion of the nitrogen molecule from the intermediate) 3,6‐di(pyrrol‐2‐yl)pyridazines in up to 73% yield, while under non‐catalytic conditions this reaction does not take place. This unusual result substantially extends the scope of synthetic application and mechanistic diversity of the Diels–Alder reaction. The step‐wise mechanisms involving the formation of [OH/tetrazine]⁻ or [t‐BuO/tetrazine]⁻ anionic intermediate complexes or cycloaddition of tetrazine to the acetylide anion are considered.     

Zinc(II) Triflate‐Catalyzed Divergent Synthesis of Polyfunctionalized Pyrroles

The zinc(II) triflate‐catalyzed synthesis of highly functionalized pyrroles is described. The sequence involves the preliminary preparation of α‐aminohydrazones by Michael addition of primary amines to 1,2‐diaza‐1,3‐dienes. The treatment of these intermediates with dialkyl acetylenedicarboxylates produces α‐(N‐enamino)‐hydrazones that are converted into the corresponding pyrroles. The substituents on the carbon in position four of 1,2‐diaza‐1,3‐dienes drive the regioselectivity of the ring closure process. Starting from 4‐aminocarbonyl‐1,2‐diaza‐1,3‐dienes only dialkyl 1‐substituted 5‐aminocarbonyl‐1H‐pyrrole‐2,3‐dicarboxylates are achieved by Lewis acid‐catalyzed ring closure. A screening of several Lewis/Brønsted acid catalysts is performed. Zinc(II) triflate is the most efficient catalyst. Under similar reaction conditions, employing 4‐alkoxycarbonyl‐1,2‐diaza‐1,3‐dienes, only 4‐hydroxy‐1H‐pyrrole‐2,3‐dicarboxylates are synthesized. These latter reactions can be accomplished regioselectively also in one pot. Using 4‐aminocarbonyl‐1,2‐diaza‐1,3‐dienes, diamines and dialkyl acetylenedicarboxylates the sequence provides the corresponding α,ω‐di(N‐pyrrolyl)alkanes.     

Synthesis and Characterization of Hyperbranched Poly(β‐ketoester) by the Michael Addition

Summary: A novel hyperbranched poly(β‐ketoester) was synthesized from 2‐(acetoacetoxy)ethyl acrylate by the Michael addition in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as catalyst. ¹H NMR integration experiments revealed that the degree of branching in the poly(β‐ketoester) was remarkably high at a level of 82.9%. The number‐average molecular weight of the polymer was between 2 100 and 12 000 and increased with reaction temperature and conversion.

Synthesis of hyperbranched polymer by Michael addition of AAEA.     

Reaction kinetics of 2‐((2‐aminoethyl) amino) ethanol in aqueous and non‐aqueous solutions using the stopped‐flow technique

Observed pseudo‐first‐order rate constants (k_o) for the reaction between CO₂ and 2‐((2‐aminoethyl) amino) ethanol (AEEA) were measured using the stopped‐flow technique in an aqueous system at 298, 303, 308 and 313 K, and in non‐aqueous systems of methanol and ethanol at 293, 298, 303 and 308 K. Alkanolamine concentrations ranged from 9.93 to 80.29 mol m^?3 for the aqueous system, 29.99–88.3 mol m^?3 for methanol and 44.17–99.28 mol m^?3 for ethanol. Experimentally obtained rate constants were correlated with two mechanisms. For both the aqueous‐ and non‐aqueous‐AEEA systems, the zwitterion mechanism with a fast deprotonation step correlated the data well as assessed by the reported statistical analysis. As expected, the reaction rate of CO₂ in the aqueous‐AEEA system was found to be much faster than in methanol or ethanol. Compared to other promising amines and diamines studied using the stopped‐flow apparatus, the pseudo‐first‐order reaction rate constants were found to obey the following order: PZ (cyclic‐diamine) > EDA (diamine) > AEEA (diamine) > 3‐AP (primary amine) > MEA (primary amine) > EEA (primary amine) > MO (cyclic‐amine). The reaction rate constant of CO₂ in aqueous‐AEEA was double that in aqueous‐MEA, and the difference increased with an increase in concentration. All reaction orders were practically unity. With a higher capacity for carbon dioxide and a higher reaction rate, AEEA could have been a good substitute to MEA if not for its high thermal degradation. AEEA kinetic behaviour is still of interest as a degradation product of MEA. © 2012 Canadian Society for Chemical Engineering