Stereoselective synthesis and biological activities of O‐(E)‐1‐{1‐[(6‐chloropyridin‐3‐yl)methyl]‐5‐methyl‐1H‐1,2,3‐triazol‐4‐yl}ethyleneamino‐O‐ethyl‐O‐arylphosphorothioates

To find novel lead compounds having high insecticidal activity, a series of phosphorothioate derivatives containing 1,2,3‐triazole and pyridine rings were synthesized by the reaction of 1‐{1‐[(6‐chloropyridin‐3‐yl)methyl]‐5‐methyl‐1H‐1,2,3‐triazol‐4‐yl}ethanone oxime with phosphorochloridothioates. Their structures were confirmed by IR, ¹H NMR, ³¹P NMR, mass spectrometry, and elemental analyses. The structure of 6c was determined by single crystal X‐ray diffraction, which is thermodynamically stable E isomer. The results of preliminary bioassay indicate that some title compounds possess insecticidal activity to some extent. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:15–20, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20367     

A convenient synthesis of novel 7‐phosphonylbenzyl‐2‐substituted pyrazolo[4,3‐e]‐1,2,4‐triazolo[1,5‐c]‐pyrimidine derivatives

A series of pyrazolo[4,3‐e]‐1,2,4‐triazolo‐[1,5‐c]pyrimidine derivatives, bearing phosphonylbenzyl chain in position 7, were conveniently synthesized in an attempt to obtain potent and selective antagonists for the A_2A adenosine receptor or potent pesticide lead compounds. Diethyl[(5‐amino‐4‐cyano‐3‐methylsulfanyl‐pyrazol‐1‐yl)‐benzyl]phospho‐nate ( 3 ), which was prepared by the cyclization of diethyl 1‐hydrazinobenzylphosphonate ( 1 ) with 2‐[bis(methylthio)methylene]malononitrile ( 2 ), reacted with triethyl orthoformate to afford diethyl[(4‐cyano‐5‐ethoxymethyleneamino‐3‐methylsulfanyl‐pyrazol‐1‐yl)‐benzyl]phosphonate ( 4 ), which reacted with various acyl hydrazines in refluxing 2‐methoxyethanol to give the target compounds 5a–h in good yields. Their structures were confirmed by IR, ¹H NMR, ¹³C NMR, MS, and elemental analysis. The crystal structure of 5e was determined by single crystal X‐ray diffraction © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:634–638, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20478     

Microwave‐assisted synthesis of some 1,2,4‐triazol‐5‐one derivatives

A series of 3‐alkyl(aryl)‐4‐(p‐hydroxy‐phenyl)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones 2 were obtained from the reaction of alkyl (aryl) ester ethoxycarbonyl hydrazones 1 with p‐hydroxy aniline. The reaction of 1 with 1,4‐diamino benzene (1:1) to afford 3‐alkyl(aryl)‐4‐(p‐aminophenyl)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones 3 . The reaction of 3 with benzaldehyde gave 3‐alkyl(aryl)‐4‐(4′‐benzilidenamino)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones 4 . All of the above reactions occurred under microwave heating and conventional methods. Their structures were confirmed by ¹H NMR, ¹³C NMR, IR, and elemental analyses. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:38–42, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20381     

A facile synthesis of new 1,2‐dihydro‐2λ5‐[1,3]oxazolo[5,4‐d][1,3,2]diazaphosphinine derivatives starting from 2‐benzoylamino‐3, 3‐dichloroacrylonitrile

Easily accessible 2‐benzoylamino‐3,3‐dichloroacrylonitrile, when treated successively with primary amines, phosphorus pentachloride, sulfur dioxide, and various N‐ or S‐nucleophiles, furnishes the corresponding derivatives of 1,2‐dihydro‐2λ⁵‐[1,3]oxazolo[5,4‐d][1,3,2]diazaphosphinine, a novel fused heterocycle. The structure of the compounds obtained is unequivocally confirmed by spectroscopic methods and X‐ray diffraction analysis. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:506–511, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20470     

Generation and detection of the radical cation and the dication derived from 4,9‐diethyl[1,4]dihydrodithiino[5,6‐f]benzotrithiole and its 5‐oxide

4,9‐Diethyl[1,4]dihydrodithiino[5,6‐f]benzotrithiole (DTBT) gave a radical cation, DTBT(•+), and a dication, DTBT(2+), on treatment with a single‐electron oxidizing reagent. Both compounds showed an ESR signal, whereas the dication, generated by this procedure, was silent for ¹H NMR. Hydrolysis of DTBT(2+) gave DTBT 1‐oxide (DTBT 1‐O) and 2‐oxide (DTBT 2‐O) together with DTBT and a mixture of several dioxides. A singlet‐state dication, DTBT(2+)‐S, which was generated upon treatment of DTBT 5‐oxide (DTBT 5‐O) with concentrated D₂SO₄, was detected by ¹H and ¹³C NMR. After 20 h, the NMR signals disappeared while the solution was active for ESR. The results suggest that (i) a species generated from DTBT by oxidation with the single‐electron oxidizing reagent is a triplet‐state dication, DTBT(2+)‐T, and (ii) DTBT(2+)‐S, initially generated, gradually isomerizes to DTBT(2+)‐T in the solution, and DTBT(2+)‐T forms a partial spin pair. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:394–401, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20445     

A convenient synthesis of 2‐(1H‐1,2,4‐triazol‐1‐yl)‐2H‐1,4‐benzothiazine derivatives

A series of 2‐(1H‐1,2,4‐triazol‐1‐yl)‐2H‐1,4‐benzothiazines were designed and synthesized by condensation of 1,2,4‐triazole‐substituted ω‐bromoacetophenones and o‐aminothiophenols with the aid of K₂CO₃ under mild conditions with moderate to high yields. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:332–336, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20434     

Synthesis of 5‐methyl‐4‐oxo‐2‐(coumarin‐3‐yl)‐N‐aryl‐3,4‐dihydrothieno[2,3‐d]‐pyrimidine‐6‐carboxamides

Possible approaches to synthesis of 5‐methyl‐4‐oxo‐2‐(coumarin‐3‐yl)‐N‐aryl‐3,4‐dihydrothieno[2,3‐d]pyrimidine‐6‐carboxamides 4 have been discussed. It is shown that the preferable approach is cyclization of 2‐iminocoumarin‐3‐carboxamides 1 , utilizing 5‐amino‐3‐methyl‐N²‐arylthiophene‐2,4‐dicarboxamides 2 as binucleophilic reagents. The proposed procedure allowed us to easily obtain 4 in two stages, using common reagents. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:341–346, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20303     

Synthesis and NMR characteristics of N‐acetyl‐4‐nitro,N‐acetyl‐5‐nitro,N‐acetyl‐6‐nitro and N‐acetyl‐7‐nitrotryptophan methyl esters

N‐acetyl‐4‐nitrotryptophan methyl ester (2), N‐acetyl‐5‐nitrotryptophan methyl ester (3), N‐acetyl‐6‐nitrotryptophan methyl ester (4) and N‐acetyl‐7‐nitrotryptophan methyl ester (5) were synthesized through a modified malonic ester reaction of the appropriate nitrogramine analogs followed by methylation with BF₃‐methanol. Assignments of the ¹H and ¹³C NMR chemical shifts were made using a combination of ¹H–¹H COSY, ¹H–¹³C HETCOR and ¹H–¹³C selective INEPT experiments. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd     

Complete assignment of 1H and 13C NMR spectra of α‐phenylsulfinyl‐N‐methoxy‐ N‐methylpropionamide and some p‐substituted derivatives

The complete assignment of the ¹H and ¹³C NMR spectra of the diastereomeric pairs of some α‐arylsulfinyl‐substituted N‐methoxy‐N‐methylpropionamides with the substituents methoxy, methyl, chloro, nitro is reported. Copyright © 2008 John Wiley & Sons, Ltd.     

A novel optically active diblock copolymer composed of poly(ethylene glycol) and poly[N‐{o‐(4‐phenyl‐4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenyl}maleimide]: Synthesis,micellization behavior,and chiroptical property

A series of optically active amphiphilic block copolymers were synthesizedby using potassium alkoxide of poly(ethylene glycol) monomethyl ether (MeOPEGO^?K⁺) to initiate the anionic polymerization of N‐{o‐(4‐phenyl‐4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenyl}maleimide [(R)‐PhOPMI]. The PEG‐macroinitiators generated in situ in the reaction between MeOPEGOH and potassium naphthylide in tetrahydrofuran. The synthetic procedure may provide the PEG‐b‐PPhOPMI copolymers with well‐defined structure, as evidenced by gel permeation chromatography, ¹H NMR, FTIR, and elemental analysis. In particular, the preparation of block copolymers having a laevorotation or dextrorotation activity was accomplished by changing the feed composition. The micellization was examined for the amphiphilic block copolymers in aqueous milieu by fluorescence spectroscopy, dynamic light scattering, and circular dichroism. The results indicate that the copolymers could form regular spherical micelles with core‐shell structure when the hydrophilic component was long enough; in contrast, the copolymers containing shorter PEG segments formed aggregates in large dimension due to the considerable interaction between hydrophobic PPhOPMI components. Also, it was found that the aggregated structure of the polymeric micelles is strongly dependent on the medium nature and the polymer concentration. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1025–1033, 2008     

Synthesis and antimicrobial activity of 5,5′‐dimethyl‐2‐oxido‐[1,3,2]‐dioxaphos‐phorinane‐2‐yl‐amino carboxylates

Synthesis of several 5,5‐dimethyl‐2‐oxido‐[1,3,2]‐dioxaphosphorinane‐2‐yl‐amino carboxylates ( 4a–j ) was accomplished through a two‐step process. This involves prior preparation of the intermediate monochloride ( 2 ), 2‐chloro‐5,5‐dimethyl [1,3,2]dioxaphosphorinane‐2‐oxide and its subsequent reaction with various amino acid esters ( 3a–j ) in dry tetrahydrofuran in the presence of triethyl amine at room temperature. They were characterized by elemental analysis, IR, ¹H, ¹³C, ³¹P NMR, and mass spectral data. Their antifungal and antibacterial activity is also evaluated. Majority of these compounds exhibited moderate antimicrobial activity in the assay. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:256–260, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20426     

Synthesis of 1‐(phenylsulfanyl/phenoxy)‐3H‐naptho[1,2,3‐de]quinoline‐2,7‐diones

A convenient method is devised to synthesize 1‐(phenylsulfanyl/phenoxy)‐3H‐naptho[1,2,3‐de]quinoline‐2,7‐dione analogs in high yield for the first time by condensation of 2‐bromo‐N‐(9,10‐dixo‐dihydro‐anthracen‐1‐yl)‐acetamide with benzenethiol/phenol using potassium carbonate. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:221–227, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20399     

Synthesis of novel N1‐(2‐furanidyl)‐5‐fluorouracil derivatives of α‐hydroxy(thio)phosphonates

Several N¹‐(2‐furanidyl)‐5‐fluorouracil derivatives of α‐hydroxythiophosphonates were synthesized via oxidation by Moffatt's method of N¹‐(2‐furanidyl)‐N³‐(hydroxyalkyl)‐5‐fluorouracil, followed by the addition of diethyl thiophosphite. The phosphonate products were obtained by the oxidation of the corresponding thiophosphonates with m‐chloroperoxybenzoic acid. The crystal structure of compound 6a was determined by X‐ray diffraction. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:211–215, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10021     

2,2,2‐triaryl‐4‐oxo‐1,3,2‐benzoxazastibinines

The hitherto unreported 4‐oxo‐1,3,2‐benzoxazastibinines 2 have been synthesized by the cyclization of disodium salt of salicylanilide ( 1 ) with Ar₃SbBr₂ (Ar = Ph, p‐tolyl, or mesityl). These compounds have been characterized by elemental analyses, molecular weight determination, and by IR, far IR, ¹H, and ¹³C NMR spectral studies. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:622–624, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10202     

Initiator effect on the cationic ring‐opening copolymerization of 2‐ethyl‐2‐oxazoline and 2‐phenyl‐2‐oxazoline

The aim of this research was to study the effect of the initiator on the resulting monomer distribution for the cationic ring‐opening copolymerization of 2‐ethyl‐2‐oxazoline (EtOx) and 2‐phenyl‐2‐oxazoline (PhOx). At first, kinetic studies were performed for the homopolymerizations of both monomers at 160 °C under microwave irradiation using four initiators. These initiators have the same benzyl‐initiating group but different leaving groups, Cl^?, Br^?, I^?, and OTs^?. The basicity of the leaving group affects the ratio of covalent and cationic propagating species and, thus, the polymerization rate. The observed differences in polymerization rates could be correlated to the concentration of cationic species in the polymerization mixture as determined by ¹H NMR spectroscopy. In a next‐step, polymerization kinetics were determined for the copolymerizations of EtOx and PhOx with these four initiators. The reactivity ratios for these copolymerizations were calculated from the polymerization rates obtained for the copolymerizations. This approach allows more accurate determination of the copolymerization parameters compared to conventional methods using the composition of single polymers. When benzyl chloride (BCl) was used as an initiator, no copolymers could be obtained because its reactivity is too low for the polymerization of PhOx. With decreasing basicity of the used counterions (Br^? > I^? > OTs^?), the reactivity ratios gradually changed from r_EtOx = 10.1 and r_PhOx = 0.30 to r_EtOx = 7.9 and r_PhOx = 0.18. However, the large difference in reactivity ratios will lead to the formation of quasi‐diblock copolymers in all cases. In conclusion, the used initiator does influence the monomer distribution in the copolymers, but for the investigated system the differences were so small that no difference in the resulting polymer properties is expected. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4804–4816, 2008     

Thiol–thione tautomeric forms recognition on the example of 4‐[3‐(2‐methyl‐furan‐3‐yl)‐5‐thioxo‐1,2,4‐triazolin‐4‐yl]acetic acid

The synthesis of 4‐[3‐(2‐methyl‐furan‐3‐yl)‐5‐thioxo‐1,2,4‐triazolin‐4‐yl]acetic acid, its structural study in the solid state, and the thiol–thione tautomeric recognition on the basis of spectroscopic data and theoretical calculations are presented. It is shown that NMR spectra, especially ¹³C and ¹⁵N, are indicative of the actual tautomeric form whereas vibrational data can be ambiguous. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:337–344, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20433     

Synthesis and characterization of new complexes of the type [Ru(CO)2Cl2 (2‐phenyl‐1,8‐naphthyridine‐kN) (2‐phenyl‐1,8‐naphthyridine‐kN′)]. Preliminary applications in homogeneous catalysis

Novel ruthenium (II) complexes were prepared containing 2‐phenyl‐1,8‐naphthyridine derivatives. The coordination modes of these ligands were modified by addition of coordinating solvents such as water into the ethanolic reaction media. Under these conditions 1,8‐naphthyridine (napy) moieties act as monodentade ligands forming unusual [Ru(CO)₂Cl₂(η¹‐2‐phenyl‐1,8‐naphthyridine‐ kN )(η¹‐2‐phenyl‐1,8‐naphthyridine‐kN′)] complexes. The reaction was reproducible when different 2‐phenyl‐1,8‐naphthyridine derivatives were used. On the other hand, when dry ethanol was used as the solvent we obtained complexes with napy moieties acting as a chelating ligand. The structures proposed for these complexes were supported by NMR spectra, and the presence of two ligands in the [Ru(CO)₂Cl₂(η¹‐2‐phenyl‐1,8‐naphthyridine‐ kN )(η¹‐2‐phenyl‐1,8‐naphthyridine‐kN′)] type complexes was confirmed using elemental analysis. All complexes were tested as catalysts in the hydroformylation of styrene showing moderate activity in N,N′‐dimethylformamide. Copyright © 2008 John Wiley & Sons, Ltd.     

Syntheses of multicyclic poly(ether sulfone)s from 5,5′,6,6′‐tetrahydroxy‐3,3,3′,3′‐tetramethyl spirobisindane and 4,4′‐bis(4‐chlorophenyl) sulfones

5,5′,6,6′‐Tetrahydroxy‐3,3,3′,3′‐tetramethyl spirobisindane (TTSBI) was polycondensed with 4,4′‐dichlorodiphenyl sulfone (DCDPS) or with 4,4′‐bis(4‐chlorophenyl sulfonyl) biphenyl (BCSBP) in DMSO. Concentration and feed ratio were optimized to avoid gelation and to obtain a maximum yield of multicyclic polyethers free of functional groups. Regardless of these reaction conditions, only low fractions of perfect multicycles were obtained from DCDPS apparently due to steric hindrance of ring closure. Under the same conditions high fractions of perfect multicycles were achieved with the longer and more flexible DCSBP. The reaction products were characterized by MALDI‐TOF mass spectrometry, ¹H‐NMR spectroscopy viscosity, and DSC measurements. Relatively low glass transition temperatures (T_gs ≈ 160–175 °C) were found. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3732–3739, 2008     

Luminescence properties of soluble 2,2′,7,7′‐Tetrakis(2‐(9‐hexyl‐9H‐carbazol‐3‐yl)‐vinyl)‐9,9′‐spirobifluorene‐labeled dendrimers: Photoluminescence and electroluminescence

New light emitting dendrimers were synthesized by reacting 3,5‐bis‐(3,5‐bis‐benzyloxy‐benzyloxy)‐benzoic acid or 3,5‐bis‐[3,5‐bis‐(3,5‐bis‐benzyloxy‐benzyloxy)‐benzyloxy]‐benzoic acid with a carbazolyl vinyl spirobifluorene moiety. A blue‐emitting core dye was encapsulated by multibenzyloxy dendrons, and two dendrimers having different densities of dendrons were prepared. Photoluminescence (PL) studies of the dendrimers demonstrated that at the higher density of benzyloxy dendrons, the featureless vibronic transitions were improved, causing lesser excimer emission. The similarity of the solution and solid emission spectra of the larger dendrimer, 10 , revealed the suppression of molecular aggregation in the solid film, which is attributed to the presence of the bulky benzyloxy dendrons. The electroluminescence spectra of multilayered devices made using 10 predominantly exhibited blue emissions; similar emission was observed in the PL spectra of its thin film. The multilayered devices made using 3 , 9 , and 10 showed luminances of 1021 cd m^?2 at 5 V, 916 cd m^?2 at 6 V, and 851 cd m^?2 at 6.5 V, respectively. The largest dendrimer, 10 , bearing a greater number of benzyloxy dendrons, exhibited a blue‐like emission with CIE 1931 chromaticity coordinates of x = 0.16 and y = 0.13, which is due to the influence of a higher shielding effect. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 501–514, 2008     

Ring‐opening polymerization of 1,4‐dioxan‐2‐one initiated by lanthanum isopropoxide in bulk

Lanthanum isopropoxide (La(OiPr)₃) has been synthesized and employed for ring‐opening polymerization of 1,4‐dioxan‐2‐one in bulk as a single‐component initiator. The influences of reaction conditions such as initiator concentration, reaction time, and reaction temperature on the polymerization were investigated. The kinetics indicated that the polymerization is first‐order with respect to the monomer concentration. The Mechanistic investigations according to ¹H NMR spectrum analysis demonstrated that the polymerization of PDO proceeded through a coordination‐insertion mechanism with a rupture of the acyl‐oxygen bond of the monomer rather than the alkyl‐oxygen bond cleavage. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5214–5222, 2008