Synthesis of 1,3‐Selenazol‐2(3H)‐imines

The reaction of N,N′‐diarylselenoureas 16 with phenacyl bromide in EtOH under reflux, followed by treatment with NH₃, gave N,3‐diaryl‐4‐phenyl‐1,3‐selenazol‐2(3H)‐imines 13 in high yields (Scheme 2). A reaction mechanism via formation of the corresponding Se‐(benzoylmethyl)isoselenoureas 18 and subsequent cyclocondensation is proposed (Scheme 3). The N,N′‐diarylselenoureas 16 were conveniently prepared by the reaction of aryl isoselenocyanates 15 with 4‐substituted anilines. The structures of 13a and 13c were established by X‐ray crystallography.     

N,N,N′,N′‐Tetrabromobenzene‐1,3‐Disulfonamide and Poly(N‐Bromo‐N‐Ethyl‐Benzene‐1,3‐Disulfonamide) as Efficient Catalysts for the Methoxymethylation of Alcohols under Solvent‐Free Conditions

Methoxymethylation of a variety of alcohols was performed using formaldehyde dimethyl acetal in the presence of N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide [TBBDA] and poly(N‐bromo‐N‐ethylbenzene‐1,3‐disulfonamide) [PBBS] as catalysts at room temperature and solvent‐free conditions. The methoxymethyl ethers (MOM‐ethers) were obtained with good to excellent yields.     

Highly stable electrochromic polyamides based on N,N‐bis(4‐aminophenyl)‐N′,N′‐bis(4‐tert‐butylphenyl)‐1,4‐phenylenediamine

A new triphenylamine‐containing aromatic diamine monomer, N,N‐bis(4‐aminophenyl)‐N′,N′‐bis(4‐tert‐butylphenyl)‐1,4‐phenylenediamine, was synthesized by an established synthetic procedure from readily available reagents. A novel family of electroactive polyamides with di‐tert‐butyl‐substituted N,N,N′,N′‐tetraphenyl‐1,4‐phenylenediamine units were prepared via the phosphorylation polyamidation reactions of the newly synthesized diamine monomer with various aromatic or aliphatic dicarboxylic acids. All the polymers were amorphous with good solubility in many organic solvents, such as N‐methyl‐2‐pyrrolidinone (NMP) and N,N‐dimethylacetamide, and could be solution‐cast into tough and flexible polymer films. The polyamides derived from aromatic dicarboxylic acids had useful levels of thermal stability, with glass‐transition temperatures of 269–296 °C, 10% weight‐loss temperatures in excess of 544 °C, and char yields at 800 °C in nitrogen higher than 62%. The dilute solutions of these polyamides in NMP exhibited strong absorption bands centered at 316–342 nm and photoluminescence maxima around 362–465 nm in the violet‐blue region. The polyamides derived from aliphatic dicarboxylic acids were optically transparent in the visible region and fluoresced with a higher quantum yield compared with those derived from aromatic dicarboxylic acids. The hole‐transporting and electrochromic properties were examined by electrochemical and spectro‐electrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium‐tin oxide‐coated glass substrate exhibited two reversible oxidation redox couples at 0.57–0.60 V and 0.95–0.98 V versus Ag/AgCl in acetonitrile solution. The polyamide films revealed excellent elcterochemical and electrochromic stability, with a color change from a colorless or pale yellowish neutral form to green and blue oxidized forms at applied potentials ranging from 0.0 to 1.2 V. These anodically coloring polymeric materials showed interesting electrochromic properties, such as high coloration efficiency (CE = 216 cm²/C for the green coloring) and high contrast ratio of optical transmittance change (ΔT%) up to 64% at 424 nm and 59% at 983 nm for the green coloration, and 90% at 778 nm for the blue coloration. The electroactivity of the polymer remains intact even after cycling 500 times between its neutral and fully oxidized states. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2330–2343, 2009     

N,N,N′,N′‐Tetraalkylaminoazoxybenzene Derivatives; Convenient Synthesis and Mechanistic Study

N,N,N′,N′‐tetraalkyaminoazoxybenzene derivatives were conveniently prepared by the coupling of N,N‐dialkylnitrosoaniline in the presence of acetone and KOH. The reaction mechanism was proposed and investigated, and the structure of compound 3b was also confirmed by single crystal X‐ray diffractometry.     

Poly(N‐bromobenzene‐1,3‐disulfonamide) and N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide as a mild and efficient catalyst for chemoselective thioacetalization of carbonyl functions and transthioacetalization reactions

Poly(N‐bromobenzene‐1,3‐disulfonamide) and N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide are effective catalysts for chemoselective dithioacetalization of aldehydes in the presence of ketones under neutral conditions. J. Heterocyclic Chem., (2011).     

Influence of tertiary diamines on the synthesis of high‐molecular‐weight poly(1,3‐cyclohexadiene)

The living synthesis of poly(1,3‐cyclohexadiene) was performed with an initiator adduct that was synthesized from a 1:2 (mol/mol) mixture of N,N,N′,N′‐tetramethylethylenediamine (TMEDA) and n‐butyllithium. This initiator, which was preformed at 65 °C, facilitated the synthesis of high‐molecular‐weight poly(1,3‐cyclohexadiene) (number‐average molecular weight = 50,000 g/mol) with a narrow molecular weight distribution (weight‐average molecular weight/number‐average molecular weight = 1.12). A plot of the kinetic chain length versus the time indicated that termination was minimized and chain transfer to the monomer was eliminated when a preformed initiator adduct was used. Chain transfer was determined to occur when the initiator was generated in situ. The polymerization was highly sensitive to both the temperature and the choice of tertiary diamine. The use of the bulky tertiary diamines sparteine and dipiperidinoethane resulted in poor polymerization control and reduced polymerization rates (7.0 × 10⁻⁵ s⁻¹) in comparison with TMEDA‐mediated polymerizations (1.5 × 10⁻⁴ s⁻¹). A series of poly(1,3‐cyclohexadiene‐block‐isoprene) diblock copolymers were synthesized to determine the molar crossover efficiency of the polymerization. Polymerizations performed at 25 °C exhibited improved molar crossover efficiencies (93%) versus polymerizations performed at 40 °C (80%). The improved crossover efficiency was attributed to the reduction of termination events at reduced polymerization temperatures. The microstructure of these polymers was determined with ¹H NMR spectroscopy, and the relationship between the molecular weight and glass‐transition temperature at an infinite molecular weight was determined for polymers containing 70% 1,2‐addition (150 °C) and 80% 1,4‐addition (138 °C). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1216–1227, 2005     

A Copper(II) Ion‐Selective Potentiometric Sensor Based on N,N′,N″,N′′′‐Tetrakis(2‐pyridylmethyl)‐1,4,8,11‐tetraazacyclotetradecane in PVC Matrix

The simple PVC‐based membrane containing N,N′,N″,N′′′‐tetrakis(2‐pyridylmethyl)‐1,4,8,11‐tetraazacyclotetradecane (tpmc) as an ionophore and dibutyl phthalate as a plasticizer, directly coated on a glassy carbon electrode was examined as a new sensor for Cu²⁺ ions. The potential response was linear within the concentration range of 1.0×10^?1–1.0×10^?6 M with a Nernstian slope of 28.8 mV/decade and detection limit of 7.0×10^?7 M. The electrode was used in aqueous solutions over a wide pH range (1.3–6). The sensor exhibited excellent selectivity for Cu²⁺ ion over a number of cations and was successfully used in its determination in real samples.     

Synthesis and biological activity of novel N‐benzoyl‐N‐tert‐butyl‐N′‐(β‐triphenylgermyl)propionylhydrazines

A series of new N‐benzoyl‐N‐tert‐butyl‐N′‐(β‐triphenylgermyl)propionylhydrazines were synthesized by the condensation reaction of β‐triphenylgermyl propanoic acid with N‐benzoyl‐N‐tert‐butylhydrazines in good yields by using N,N′‐dicyclohexylcorbodiimide as dehydrating agent. These title compounds were evaluated for molting hormone mimicking activity. The results of bioassay showed that the compounds exhibit moderate larvicidal activity, and toxicity assays indicated that the title compounds can induce a premature, abnormal and lethal larval molt. We found that the title compounds possess potential anticancer activities in vitro. Copyright © 2002 John Wiley & Sons, Ltd.     

A three‐dimensional cadmium(II) coordination polymer: poly[[[μ‐4,4′‐(propane‐1,3‐diyl)dipyridine‐κ2N:N](μ‐3,3′‐thiodipropionato‐κ3O,O′:O)cadmium(II)] monohydrate]

In the title coordination polymer, {[Cd(C₆H₈O₄S)(C₁₃H₁₄N₂)]·H₂O}_n, the Cd^II atom displays a distorted octahedral coordination, formed by three carboxylate O atoms and one S atom from three different 3,3′‐thiodipropionate ligands, and two N atoms from two different 4,4′‐(propane‐1,3‐diyl)dipyridine ligands. The Cd^II centres are bridged through carboxylate O atoms of 3,3′‐thiodipropionate ligands and through N atoms of 4,4′‐(propane‐1,3‐diyl)dipyridine ligands to form two different one‐dimensional chains, which intersect to form a two‐dimensional layer. These two‐dimensional layers are linked by S atoms of 3,3′‐thiodipropionate ligands from adjacent layers to form a three‐dimensional network.     

Unexpected Spiroproducts from the Reaction of N‐Benzoylglycine with Ortho‐Formylbenzoic Acids −3,5′‐Dioxo‐2′‐Phenyl‐1,3‐Dihydrospiro[Indene‐2,4′‐[1,3]Oxazol]‐1‐yl Acetates: Establishments of Their Structure

This paper describes a method of preparation of new 3,5′‐dioxo‐2′‐phenyl‐1,3‐dihydrospiro[indene‐2,4′‐[1,3]oxazol]‐1‐yl acetate and its 5‐chloro‐ and bromoderivatives as products of interaction of N‐benzoylglycine (hippuric acid) with corresponding ortho‐formylbenzoic acids. The reaction carried out in acetic anhydride media in the presence of piperidine as catalyst. The novel spirocompounds were purified by column chromatography from multicomponent reaction mixtures. The composition of the spiro‐products was confirmed by C, H, N element analysis. The structure was established by IR, MS, ¹H‐ and ¹³C‐NMR analysis including COSY ¹H‐¹³C experiments.     

Axially Dissymmetric Chiral (R)‐N,W‐Bis(2‐hydroxy‐3,5‐ditert‐butyl‐arylmethyl)‐1, 1′‐binaphthalene‐2,2′‐diamine as Chiral Ligands in the Reaction of Diethylzinc to Aldehydes†

Chiral ligand (A)‐N,N′‐Bis(2‐hydroxy‐3,5‐di‐tert‐butyl‐arylmethyl)‐1,1′‐binaphthalene‐2,2′‐diamine derived from the reduction of Schiff base (R)‐2,2′‐bis (3,5‐di‐tert‐butyl‐2‐hydroxybenzylideneamino)‐1, 1′‐binaphthyl with LiAlH₄, is fairly effective in the asymmetric addition reaction of diethylzinc to aldehydes by which good yields (46%‐94%) of the corresponding sec‐alcohols can be obtained in moderate ee (51%‐79%) with R configuration for a variety of aldehydes.     

Hydrazine‐based polyimides from isomeric bis(chlorophthalimide)s

3,3′‐Dichloro‐N,N′‐biphthalimide (3,3′‐DCBPI), 3,4′‐dichloro‐N,N′‐biphthalimide (3,4′‐DCBPI), and 4,4′‐dichloro‐N,N′‐biphthalimide (4,4′‐DCBPI) were synthesized from 3‐ or 4‐chlorophthalic anhydrides and hydrazine in glacial acetic acid. The yield of 3,3′‐DCBPI (90%) was much higher than that of 4,4′‐DCBPI (33%) because of the better stability of the intermediate, 3‐chloro‐N‐aminophthalimide, and 3,3′‐DCBPI. A series of hydrazine‐based polyimides were prepared from isomeric DCBPIs and 4,4′‐thiobisbenzenethiol (TBBT) in N,N‐dimethylacetamide in the presence of tributylamine. Inherent viscosity of these polymers was in the range of 0.51–0.69 dL/g in 1‐methyl‐2‐pyrrolidinone (NMP) at 30 °C. These polyimides were soluble in 1,1,2,2‐terachloroethane, NMP, and phenols. The 5% weight‐loss temperatures (T_5%s) of the polymers were near 450 °C in N₂. Their glass‐transition temperatures (T_gs) determined by dynamic mechanical thermal analysis and differential scanning calorimetry increased according to the order of polyimides based on 4,4′‐DCBPI, 3,4′‐DCBPI, and 3,3′‐DCBPI. The hydrolytic stability of these polymers was measured under acid, basic, and neutral conditions and the results indicated that the order was 3,3′‐DCBPI/TBBT > 3,4′‐DCBPI/TBBT > 4,4′‐DCBPI/TBBT. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4933–4940, 2007     

Synthesis and properties of new soluble aromatic polyamides and polyimides on the basis of N,N′‐bis(3‐aminobenzoyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

A new N‐phenylated amide (N‐phenylamide) unit containing aromatic diamine, N,N′‐bis(3‐aminobenzoyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine, was prepared by the condensation of N,N′‐diphenyl‐1,4‐phenylenediamine with 3‐nitrobenzoyl chloride, followed by catalytic reduction. Two series of organosoluble aromatic poly(N‐phenylamide‐imide)s and poly(N‐phenylamide‐amide)s with inherent viscosities of 0.58–0.82 and 0.56–1.21 dL/g were prepared by a conventional two‐stage method and the direct phosphorylation polycondensation, respectively, from the diamine with various aromatic dianhydrides and aromatic dicarboxylic acids. All polyimides and polyamides are amorphous and readily soluble in many organic solvents such as N,N‐dimethylacetamide and N‐methyl‐2‐pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with high tensile strengths. These polyimides and polyamides had glass‐transition temperatures in the ranges of 230–258 and 196–229 °C, respectively. Decomposition temperatures of the polyimides for 10% weight loss all occurred above 500 °C in both nitrogen and air atmospheres. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2564–2574, 2002     

Microwave‐Assisted Oxidation of Alcohols with N,N,N′,N′‐Tetrabromobenzene‐1,3‐Disulfonamide and Poly(N‐Bromobenzene‐1,3‐Disulfonamide) under Solvent‐Free Conditions

An efficient and mild methodology for the oxidation of primary and secondary alcohols to the corresponding carbonyl functions is described with N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide and poly(N‐bromobenzene‐1,3‐disulfonamide) using microwave irradiation under solvent‐free conditions. Aliphatic, benzylic and allylic alcohols are rapidly oxidized without over‐oxidation to carboxylic acids. Secondary carbinols are slowly oxidized so that the reaction is highly chemoselective.     

Efficient Synthesis of Triarylamines Catalyzed by Copper(I) Diazabutadiene Complexes

Cuprous chloride was coordinated by diazabutadiene (DAB‐R) ligands to form Cu(I)‐(DAB‐R) complexes, most of which have a 1:1 ratio of Cu to DAB‐R as reported. In the case of a special DAB‐ⁱPP, N,N′‐bis(2,6‐diisopropylphenyl)‐1,4‐diaza‐1,3‐butadiene, an unexpected composition of complex was found with the formula Cu(I)Cl(DAB)₂. When employed as catalyst for triarylamine synthesis from the coupling of aryl halides with primary and secondary arylamines, the new Cu(I)‐(DAB‐ⁱPP) complex displayed high efficiency.     

Synthesis of 2‐Aryl‐5‐oxo‐4‐[2‐(phenylmethylidene)hydrazino]‐2,5‐dihydro‐1H‐pyrrole‐3‐carboxylates by the Reaction between Hydrazones,Acetylenedicarboxylates, and 1‐Aryl‐N,N′‐bis(arylmethylidene)methanediamines

An efficient approach for the preparation of functionalized 2‐aryl‐2,5‐dihydro‐5‐oxo‐4‐[2‐(phenylmethylidene)hydrazino]‐1H‐pyrroles is described. The four‐component reaction between aldehydes, NH₂NH₂?H₂O, dialkyl acetylenedicarboxylates, and 1‐aryl‐N,N′‐bis(arylmethylidene)methanediamines proceeds in EtOH under reflux in good‐to‐excellent yields (Scheme 1). The structures of 4 were corroborated spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS, and, in the case of 4f , by X‐ray crystallography). A plausible mechanism for this type of reaction is proposed (Scheme 2).     

N,N′‐Dioxide/Nickel(II)‐Catalyzed Asymmetric Inverse‐Electron‐Demand Hetero‐Diels–Alder Reaction of β,γ‐Unsaturated α‐Ketoesters with Enecarbamates

N,N′‐Dioxide/nickel(II) complexes have been developed to catalyze the inverse‐electron‐demand hetero‐Diels–Alder reaction of β,γ‐unsaturated α‐ketoesters with acyclic enecarbamates. After detailed screening of the reaction parameters, mild optimized reaction conditions were established, affording 3,4‐dihydro‐2H‐pyranamines in up to 99 % yield, 99 % ee and more than 95:5 d.r. The catalytic system was also efficient for β‐substituted acyclic enecarbamates, affording more challenging 2,3,4‐trisubstituted 3,4‐dihydro‐2H‐pyranamine with three contiguous stereogenic centers in excellent yields, diastereoselectivities, and enantioselectivities. The reaction could be scaled up to a gram scale with no deterioration of either enantioselectivity or yield. Based on these experiments and on previous reports, a possible transition state was proposed.     

A Novel,One‐Pot Four‐Component Route to 2′‐Thioxo‐2′,3′‐dihydrospiro[indole‐3,6′‐[1,3]thiazin]‐2‐one Derivatives

An efficient route to 2′,3′‐dihydro‐2′‐thioxospiro[indole‐3,6′‐[1,3]thiazin]‐2(1H)‐one derivatives is described. It involves the reaction of isatine, 1‐phenyl‐2‐(1,1,1‐triphenyl‐λ⁵‐phosphanylidene)ethan‐1‐one, and different amines in the presence of CS₂ in dry MeOH at reflux (Scheme 1). The alkyl carbamodithioate, which results from the addition of the amine to CS₂, is added to the α,β‐unsaturated ketone, resulting from the reaction between 1‐phenyl‐2‐(1,1,1‐triphenyl‐λ⁵‐phosphanylidene)ethan‐1‐one and isatine, to produce the 3′‐alkyl‐2′,3′‐dihydro‐4′‐phenyl‐2′‐thioxospiro[indole‐3,6′‐[1,3]thiazin]‐2(1H)‐one derivatives in excellent yields (Scheme 2). Their structures were corroborated spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS) and by elemental analyses.     

Property and Application of BACy‐Based Functional Hydrogels

Conventional polyacrylamide hydrogels prepared from the free radical polymerization between acrylamide and N,N′‐methylenebisacrylamide (NMBA) have been frequently used in the biochemical technique like the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) to resolve protein mixtures. In this study, we have prepared an alternative polyacrylamide hydrogel from the cross‐linking of acrylamide and N,N′‐bisacrylylcystamine (BACy). In addition, we have compared the BACy‐based hydrogel with the NMBA‐based polyacrylamide hydrogel for their physical properties such as swelling ratio, shear modulus, crosslink density and morphology. Moreover, we further determined whether BACy‐based polyacrylamide hydrogel could be applied to SDS‐PAGE and proteomics research. The results showed that this type of hydrogel is capable of separating proteins and facilitates further in‐gel protein digestion and the following protein identifications by mass spectrometry. In summary, our study provides a basis for the putative application of BACy‐based hydrogels.     

Accelerating effects of N‐aryl‐N′,N′‐dialkyl ureas on epoxy‐dicyandiamide curing system

This report focuses on epoxy‐dicyandiamide (DICY) curing system accelerated by N‐aryl‐N′,N′‐dialkyl urea, aiming at clarifying the accelerating mechanism and the relationship between accelerating effect and molecular structure of the accelerators. Nine N‐aryl‐N′,N′‐dialkyl ureas were synthesized and investigated with measurements of differential scanning calorimetry, thermo gravimetric/differential thermal analysis and NMR spectroscopy. The results revealed that the ureas released the corresponding secondary amines by the thermal dissociation in the presence of epoxide, which led to the formation of tertiary amines that catalyze the addition reaction of DICY to epoxide. Moreover, a tendency that the ureas able to release more compact amines exhibited higher acceleration effects was discovered. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010