Highly convenient one‐pot conversion of aryl acylals or aryl aldehyde bisulfites into dihydropyrimidones using BI(NO3)3⋅5H2O

A new, facile, and efficient one‐pot deprotection–cyclocondensation method is presented for the Biginelli reaction from aryl acylals or aryl aldehyde bisulfites in the presence of catalytic amounts of Bi(NO₃)₃ ⋅ 5H₂O under solvent‐free conditions. In addition, high levels of chemoselectivity for this synthesis have been achieved. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:684–687, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20352     

Synthesis of stannic(IV) complexes: Their structural elucidation in solid and solution state and antimicrobial activity

A series of organotin(IV) thiocarboxylates have been synthesized with the general formula R₂SnL₂ and R₃SnL (R = Ph₂(I), Me₃(II), n‐Bu₃(III), Ph₃(IV), Cy₃(V), Me₂(VI), n‐Bu₂(VII), and L = piperidine‐1‐thiocarboxylic acid) in anhydrous toluene under the reflux conditions. The complexes were characterized by microanalysis, IR, ¹H and ¹³C NMR, mass spectrometry, and XRD. NMR data revealed that thiocarboxylic acid acts as bidentate, and complexes exhibit the four‐coordinated geometry in solution state. In solid state, diorganotin complexes exhibit the hexa‐coordinated geometry whereas the triorganotin(IV) compounds show the five‐coordinated geometry. These complexes were also tested for their antimicrobial activity along with the ligand against different animals, plant pathogens, and Artemia salina. All complexes with few exceptions show high activity as compared to the ligand. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:664–674, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20380     

Synthesis and anti‐HIV activity of new chiral 1,2,4‐triazoles and 1,3,4‐thiadiazoles

5‐substituted 4‐(4‐chlorophenyl)‐4H‐1,2,4‐triazol‐3‐thiones 3 and 2‐substituted 5‐(4‐chlorophenylamino)‐1,3,4‐thiadiazoles 4 were prepared from the intermediate thiosemicarbazides 2 under basic and acidic conditions, respectively. The thiosemicarbazides, in turn, were prepared by the reaction of hydrazides 1 with 4‐chlorophenylisothiocyanate in MeOH. Some of the new synthesized compounds were assayed against HIV‐1 and HIV‐2 in MT‐4 cells. All the compounds were inactive except 3f , which showed an EC₅₀ value of 23.9 μg/mL and 9.9 μg/mL against HIV‐1 and HIV‐2 with a therapeutic index of 3 and 7, respectively. It means that compound 3f was cytotoxic to MT‐4 cells at CC₅₀ of 72.7 μg/mL in both strains. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:316–322, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20282     

Substituted pyridopyrimidinones, 1: Convenient PTC alkylation and halogenation of 2‐hydroxy‐4H‐pyrido[1,2‐a]pyrimidin‐4‐one

Alkylation of 2‐hydroxy‐4H‐pyrido[1,2‐a]pyrimidin‐4‐one ( 1 ) was investigated under solid–liquid phase transfer catalysis conditions (PTC), using tetrabutylammonium bromide and potassium carbonate. The reaction with alkyl halides led to the formation of various 2‐alkoxy products, in fair yields. Reaction of compound 1 with epichlorohydrin and chloroacetonitrile, under the same PTC conditions, afforded novel O1,O3‐disubstituted glycerol and oxazolopyridopyrimidone betaine derivatives, respectively. Some 3‐halo‐, 3,3‐dihalo, and/or 2,3‐dihalopyrido[1,2‐a]pyrimidines were also prepared using different halogenating agents at different reaction conditions. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:19–27, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20245     

Functionally terminated poly(methyl acrylate) by SET‐LRP initiated with CHBr3 and CHI3

The single‐electron transfer living radical polymerization (SET‐LRP) of methyl acrylate initiated with bromoform (CHBr₃) and iodoform (CHI₃) and catalyzed by Cu(0)/Me₆‐TREN in DMSO at 25 °C provides a reliable method to prepare poly (methyl acrylate) (PMA) with active chain ends and controlled structure that can undergo subsequent functionalization to provide strategies for the synthesis of different block copolymers and other complex architectures. A detailed kinetic and structural analysis was used to assess the scope and the limitations of CHBr₃ and CHI₃ as initiators under SET‐LRP conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 278–288, 2008     

Two novel benzenedicarboxylate‐metal complexes: synthesis,crystal structures and fluorescent properties

Two novel benzenedicarboxylate–metal complexes, [Sm(nphth)(Hnphth)(H₂O)₃^?H₂O]₂ and [Zn(nphth)(bipy)(H₂O) ?H₂O]₂ (2) (H₂nphth = 3‐nitrophthalic acid, bipy = 2,2′‐bipyridine), have been synthesized under hydrothermal condition and characterized by single‐crystal X‐ray diffraction. Both complex 1 and 2 exhibit a dimeric structure, and nphth ligand shows different coordination mode in the f‐block and d‐block complexes. The fluorescent properties of two complexes are investigated; the results reveal that the two complexes show different kinds of fluorescence. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis of novel 5‐aryl‐1H‐tetrazoles

In this study phenylselenocyanate and some of its derivatives (o‐Cl, p‐Cl, p‐Br, o‐NO₂, p‐NO₂, o‐CH₃, p‐CH₃, o‐COOH, p‐COOH, p‐OCH₃ substituted) were synthesized ( 3a–3j ). The synthesized compounds were converted to 5‐aryl‐1H‐tetrazole ( 4a–4j ), by Et₃N ċ HCl‐NaN₃ in toluene, which are a new series of phenylselanyl‐1H‐tetrazoles. The structure of all the presently synthesized compounds were confirmed using spectroscopic methods (FTIR, ¹H NMR, MS). © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:255–258, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20293     

An efficient and green preparation of 9‐arylacridine‐1,8‐dione derivatives

9‐Arylacridine‐1,8‐dione derivatives were prepared in an ionic liquid medium in the presence of CeCl₃ ċ 7H₂O through an one‐pot procedure. The method presented here has the advantages of environmental benignancy, good‐to‐excellent yields, and simple operational procedure. Moreover, the solvent and catalyst can be easily recovered and reused for several runs without obvious loss of activity. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:786–790, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20410     

Reaction of a cyclic triphosphenium ion with triflic acid and SnX2 (X = Br or Cl): A 31P NMR study

The di‐ium dication formed by triflic acid protonation of the cyclic triphosphenium ion derived from 1,4‐bis‐diphenylphosphinobutane, (dppb), and P₃(X = Br or Cl) decomposes via an acyclic dication bearing a  PHX group; this intermediate is reduced by SnX₂ in the presence of HX to yield a dication with a  PH₂ primary phosphane terminal group, which is comparatively stable. The structure of this species has been unequivocally confirmed by ³¹P solution‐state NMR spectroscopy. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:609–612, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20302     

Model reaction for thermally latent curing through addition of hemiacetal ester and epoxide by schiff‐base–zinc halide complexes

Schiff‐base–zinc halide complexes (ZnX₂/ 1 ) thermal‐latently catalyze the reaction of glycidyl phenyl ether (2) and 1‐propoxyethyl 2‐ethylhexanoate (3) that proceeds at moderately elevated temperatures. The catalysis by the ZnX₂/ 1 complexes proceeds via the thermal dissociation of 3 to produce the corresponding carboxylic acid that nucleophilically attacks 2 predominantly over the thermally dissociated vinyl ether. ZnX₂/ 1 complexes catalyze both the dissociation of 3 to produce the carboxylic acid intermediate and its addition to 2 . Although conventional latent catalysts for this reaction exhibit Lewis acidities under ambient conditions that are responsible to the gradual degradation of hemiacetal esters and the polymerization of epoxides, a mixture of 2 , 3 , and ZnX₂/ 1 can be stored for 3 months at ambient conditions. The stored mixture is as active as the freshly prepared mixture, keeping the excellent activity and latency of ZnX₂/ 1 . As well as the model reaction, the thermally latent polyaddition of bisphenol A diglycidyl ether (9) and di‐1‐propoxyethyl adipate (10) is also promoted with ZnCl₂/ 1 at a moderate elevated temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3370–3379, 2007     

Ethylene polymerization and copolymerization with 10‐undecen‐1‐ol using the catalyst system DADNi(NCS)2/MAO

The catalyst DADNi(NCS)₂ (DAD = (ArN?C(Me)? C(Me)?ArN); Ar = 2,6‐C₆H₃), activated by methylaluminoxane, was tested in ethylene polymerization at temperatures above 25 °C and variable Al/Ni ratio. The system was shown to be active even at 80 °C and when supported on silica. However, catalyst activity decreased. The catalyst system was also tested in ethylene and 10‐undecen‐1‐ol copolymerization at different ethylene pressures. The best activities were obtained at low polar monomer concentration (0.017 mol/L), using triisopropylaluminum (Al‐i‐Pr₃) to protect the polar monomer. The incorporation of the comonomer increased with the increase of polar monomer concentration. According to ¹³C NMR analyses, all the resulting polyethylenes were highly branched and the polar monomer incorporation decreased as ethylene pressure increased. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5199–5208, 2007     

Preparation and properties of polyethoxysilsesquioxane‐C60 hybrids

Free‐standing films of C₆₀‐polyethoxysiloxane hybrids were prepared, and their optical limiting properties were evaluated. Triethoxysilylated C₆₀, with a formula of H₃C₆₀[Si(OEt)₃]₃, was synthesized by the hydrolysilylation of C₆₀ with triethoxysilane in the presence of platinum catalyst. C₆₀‐polyethoxysiloxanes were prepared by a cohydrolytic polycondensation of triethoxysilylated C₆₀ with tetraethoxysilane in a molar ratio of Si/C₆₀ = 10–1000 under nitrogen flow. The molecular weight of C₆₀‐polyethoxysiloxane increased with a decrease of Si/C₆₀. Transparent and flexible free‐standing films were prepared by aging an ethanol solution of C₆₀‐polyethoxysiloxane at 80 °C for 6–8 days. The mechanical strength and Young's modulus increased with a decrease in Si/C₆₀. These free‐standing films showed an optical limiting property, for which the threshold value decreased from 1163 mJ/cm² (Si/C₆₀ = 1000) to 130 mJ/cm² (Si/C₆₀ = 10) with a decrease of Si/C₆₀. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3273–3279, 2007     

Reactions of carbanions with 2,4‐dinitrofluorobenzene leading to stable heptatrienide moieties

Reactions of NCCH₂COOMe 1a and CH₂(CN)₂ 1b with 2,4‐dinitrofluorobenzene 2 at the presence of Et₃ N result in deeply colored crystalline stable salts 4a,4b with anions that contain a system of conjugated bonds. Similar reaction of 2 with phosphorus‐containing zwitterion 6 bearing ethoxy‐ and cyano‐groups at the carbanion center is the first example of the reaction leading to the formation of P‐zwitterion 9 with a negatively charged heptatriene moiety. This reaction proceeds via a new route of decomposition of the intermediate σ‐complex 7 occurring with formation of ethylfluoroformate. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:108–115, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20267     

Synthesis of novel N‐alkyl/aryl‐N′‐(4‐arylthiazol‐2‐yl)‐N″‐xylosyl guanidines

The reaction of 2,3,4‐tri‐O‐acetyl‐β‐D‐xylopyranosyl isothiocyanate ( 1 ) and 2‐amino‐4‐arylthiazoles ( 2 ) gave xylosylthioureas 3 . These thiourea derivatives reacted with alkyl/aryl amine in the presence of HgCl₂ to give a new series of N‐alkyl/aryl‐N″‐(4‐arylthiazol‐2‐yl)‐N″‐xylosyl guanidines 4 . Some of the synthesized guanidines were screened for their biological activity. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:688–694, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20379     

Polymerization of vinyl compounds in the presence of perfluoroisopropenyl ester

To report a new polymerization reaction phenomenon, this article examines the polymerization of butyl vinyl ether and N‐vinylcarbazole in the presence of 2‐benzoxypentafluoropropene [CF₂?C(CF₃)OCOC₆H₅ or BPFP]. The homopolymer of butyl vinyl ether was produced in the presence of a catalytic amount of BPFP in high yields. N‐Vinylcarbazole, which is a monomer well‐known for producing its homopolymer under cationic polymerization conditions, also yielded its homopolymer in the presence of BPFP. It was concluded that some cationic species would be yielded by the addition of BPFP. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 908–910, 2007.     

Application of palladacycle catalyst in the synthesis of mono‐arylpyridyl bromides

The mono‐arylpyridyl bromides are very useful key intermediates that can be further functionalized to generate bioactive compounds. It is possible to obtain mono‐arylation products of 3,5‐dibromopyridine with high preferentiality and high yields by air‐ and moisture‐stable palladacycle (catalyst II ) catalyzed Suzuki reaction of 3,5‐dibromopyridine with a series of arylboronic acids—ester under the conditions of K₂CO₃–toluene–methanol (4:1, v/v), reflux (75 °C), 5.6 equiv. of 3,5‐dibromopyridine with the ratio (mono:bis) ranging from of 99:1 to 90:10. This new method could also be used to easily achieve pyridyl? pyridyl bond formation to afford 3‐bromo‐5‐pyridylpyridine ( 3j ). Copyright © 2007 John Wiley & Sons, Ltd.     

Lithium bis(2‐phenylphosphidoethyl)phenyl‐phosphine: A reactive phosphorus intermediate

Bis(2‐phenylphosphinoethyl)phenylphosphine, PhP(CH₂CH₂PPh₂)₂, reacts with lithium in tetrahydrofuran to give the corresponding lithium bis(2‐diphenylphosphidoethyl)phenylphosphine, Li₂[PhP(CH₂CH₂PPh)₂]. The lithium diphosphide is identified by NMR spectroscopy and further characterized through arylation with excess brombenzene to reform the starting phosphine, PhP(CH₂CH₂PPh₂)₂. Initial reactivity studies of the diphosphide, PhP(CH₂CH₂PPh), with some alkylhalides are also described. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:675–678, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20351     

Synthesis of graft copolymers of xyloglucan and acrylonitrile

Xyloglucan (XG), a water‐soluble food grade polysaccharide is reported as a substrate for the graft copolymerization of acrylonitrile (AN). XG was extracted from tamarind seed mucilage. Polymerization was initiated both by ceric ion in aqueous medium under N₂ atmosphere and with microwave (MW) irradiation. The progress of the reaction was monitored gravimetrically. The effect of different reaction parameters such as monomer concentration, level of ceric ammonium nitrate/HNO₃ (CAN) initiator, reaction time and temperature, and MW power on the percent grafting (PG) was studied. Grafting of polyacrylonitrile (PAN) onto XG was confirmed by Fourier‐transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscope (SEM) techniques have been used to study the thermal and morphological changes in the materials. Copyright © 2007 John Wiley & Sons, Ltd.     

Investigation into the ROMP copolymerization of peptide‐ and PEG‐functionalized norbornene derivatives

The ring‐opening metathesis polymerizations (ROMP), using RuCl₂ (PCy₃)₂CHPh, of a series of peptide‐functionalized norbornene derivatives have been investigated. Incorporation of a PEG‐monomer was found to prevent premature precipitation of polymer strands during the course of polymerization reactions and yield water compatible polymers in high conversions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3178–3190, 2007     

Excess polarizabilities upon excitation from the ground state to the first dipole‐allowed excited state of diphenylpolyenes

This paper discusses the excess polarizabilities upon excitation from the ground state to the first dipole‐allowed excited state (S₁) of diphenylpolyenes by using the time‐dependent density functional theory. Two hybrid exchange‐correlation (xc) potentials Becke‐3 Lee‐Yang‐Parr (B3LYP) and Perdew‐Burke‐Ernzerhof (PBE1PBE) were employed. Our calculations indicate that the magnitude of the excess polarizability will decrease while the molecule evolves from the unrelaxed S₁ state to the relaxed S₁ state. This decreasing trend is found to be independent of substituents, though substituents can change the value of the excess polarizability. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007