bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of some novel 2‐{2‐[1‐(3‐substituted‐phenyl)‐1H‐1,2,3‐triazol‐4‐yl‐] ethyl}‐1‐substituted‐1H‐benzo [d] imidazole derivatives
Authors: Jadhav Ganesh R. , Shaikh Mohammad U. , Shingare Murlidhar S. , Gill Charansingh H.
Published: March 2009

magnified image

Synthesis of some novel 2‐{2‐[1‐(3‐substitutedphenyl)‐1H‐1,2, 3‐triazol‐4‐yl‐]ethyl)‐1H‐benzo[d]‐imidazole derivatives, by the condensation of o‐phenylenediamine with 3‐(1‐(3‐substituted‐phenyl)‐1H‐1,2,3‐triazol‐4‐yl) propanoic acid and then subsequent reactions with different substituted alkyl halides as electrophiles are mentioned. The synthesized compounds were characterized by 1H NMR, EI‐MS and IR spectroscopic techniques.
A rapid and efficient method for synthesis of pyrimido[1,2‐a]‐benzimidazole derivatives under microwave irradiation
Authors: Zhuang Qiya , Li Chunmei , Tu Shujiang , Cao Longji , Zhou Dianxiang , Shao Qingqing , Guo Cheng
Published: March 2009

magnified image

A rapid and efficient method for synthesis pyrimido[1,2‐a]benzimidazole derivatives from readily available starting materials is accomplished under microwave irradiation. This method has the advantages of short reaction time, operational simplicity, increased safety for small‐scale high‐speed synthesis, and minimal environment impact.
The stereoselective synthesis of e‐1,2‐bis(3‐indolizinyl)ethylenes by the reactions of 3‐thioformylindolizines with n‐tributylphosphine
Authors: Liu Weiwei , Zhao Yueqiang , Tu Shujiang , He Ting , Hu Hongwen
Published: March 2009

magnified image

3‐Thioformylindolizines undergo novel reductive coupling reaction in the presence of tributylphosphine to give E‐1,2‐bis(3‐indolizinyl)ethylenes in high yield. These reactions proceed via (3‐indolizinyl)methylene carbene intermediate and provide a new, stereoselective synthesis of the bis(3‐indolizinyl)ethylene derivatives highly.
Regioselectivity of the reactions of 4,5‐diphenylimidazole‐2‐thione with 1‐chloro‐2,3‐epoxy‐propane and 1‐bromo‐propene, efficient precursors for imidazo[2,1‐b]thiazine and thiazole. Effect of microwave and solid support
Authors: Aouad Mohamed. R. , Rezki Nadje T. , El Ahsry El Sayed H.
Published: March 2009

magnified image

A solid support under microwave (MW) irradiation without solvent allowed the synthesis of the 2,3‐epoxy‐propyl‐thioimidazole 4, regioselectively, and prohibited its cyclization to give the imidazo[2,1‐b]thiazine 3 from the reaction of 4,5‐diphenylimidazole‐2‐thione (1) with 1‐chloro‐2,3‐epoxy‐propane (2). The formation of the latter required basic conditions whereby it became the sole product; the change of the basic catalyst changed the ratio of the two products under both conventional and microwave (MW) conditions. A regioselective allylation of 1 with allyl bromide in presence of triethylamine gave the S‐allyl 8, while in presence of potassium carbonate led to the S,N‐bis(allylated) derivative 9. The intramolecular ring closure of 8 in presence of sulfuric acid afforded the imidazothiazole 16. Protection of the sulfur in 1 and subsequent reaction with allyl bromide gave the N‐allylated derivative and with 2 gave N‐3‐chloro‐prop‐1‐yl derivative that shed light on the preferred route for the formation of 3 and 4. The reactivity encountered during the alkylation of 1 with 2 has been theoretically investigated by using the AM1 method.
A facile rearrangement of pyrroloindoline derivative to pyrroloquinoline: A new analogues of duocarmycins
Authors: Al‐Said Naim H. , Shawakfeh Khaled Q. , Hammad Baha A.
Published: March 2009

magnified image

Free‐radical generated at C‐7 position of indole derivative bearing N‐(3′‐chloroallyl) group prompted a regioselective intramolecular cyclization to furnish pyrroloindoline derivative, through the more favorable 5‐exo‐trig cyclization mode. The pyrroloindoline compound smoothly rearranged to pyrroloquinoline under mild conditions.
2‐Aryl‐4‐azido‐3‐(bromo/iodo)quinolines as substrates for the synthesis of primary 4‐amino‐2,3‐disubstituted quinoline derivatives
Authors: Mphahlele Malose J. , Mtshemla Vathiswa
Published: March 2009

magnified image

Staudinger reaction of the 2‐aryl‐4‐azido‐3‐bromoquinolines and 2‐aryl‐4‐azido‐3‐iodoquinolines with triphenyl phosphine in refluxing tetrahydrofuran afforded series of 2‐aryl‐3‐halogeno‐4‐(triphenylphosphoranylideneamino)quinolines. The latter were, in turn, hydrolyzed to the corresponding primary 4‐amino‐2‐aryl‐3‐(bromo/iodo)quinolines using 80% acetic acid under reflux. Tetrakis(triphenylphosphine)‐palladium(O)‐catalyzed Suzuki reaction of the 2‐aryl‐3‐iodo‐4‐(triphenylphosphoranylideneamino)‐quinolines with phenylboronic acid in dimethyl formamide in the presence of 2 M K2CO3 followed by hydrolysis of the incipient 2,3‐diaryl‐4‐(triphenylphosphoranylideneamino)quinolines with 80% acetic acid afforded the 4‐amino‐2,3‐diarylquinolines.
Ring closure reactions of pyrido[2,3‐d]pyrimidines to pyrano[2′,3′:4,5]‐ and oxazolo[5′,4′:4,5]pyrido[2,3‐d]pyrimidines
Authors: Van Tinh Dang , Stadlbauer Wolfgang
Published: March 2009

magnified image

The cyclocondensation of 5‐hydroxy‐pyrido[2,3‐d]pyrimidines 1 with malonates gives pyrano[2′,3′:4,5]‐pyrido[2,3‐d]pyrimidines 2. Nitration of 1 and reduction with zinc in the presence of carboxylic acids/anhydrides gave 2‐alkyloxazolo[5′,4′:4,5]pyrido[2,3‐d]pyrimidines 4, which were ring‐opened to 6‐aminopyrido[2,3‐d]pyrimidines 5, 6 and 7. Cyclization of 6‐aminopyrido[2,3‐d]pyrimidines 6 with benzoylchlorides 8 gave 2‐aryloxazolo[5′,4′:4,5]pyrido[2,3‐d]pyrimidines 9. Reaction conditions for the cyclization have been studied by differential scanning calorimetry (DSC).
Synthesis of 3‐aminoalkyl‐2‐arylaminoquiazolin‐4(3H)‐ones and 3,3′‐disubstituted bis‐2‐arylaminoquinazolin‐4(3H)‐ones via reactions of 1‐aryl‐3‐(2‐ethoxycarbonylphenyl)carbodiimides with diamines
Authors: Yang Xu‐Hong , Wu Ming‐Hu , Sun Shao‐Fa , Xie Jia‐Li , Ding Ming‐Wu , Xia Qing‐Hua
Published: March 2009

magnified image

1‐Aryl‐3‐(2‐ethoxycarbonylphenyl)carbodiimides 2, obtained from aza‐Wittig reactions of iminophosphorane 1 with aryl isocyanates, reacted with primary diamines in 1:1 and 2:1 molar ratio under mild conditions to give selectively the regioisomers 3‐aminoalkyl‐2‐arylaminoquinazolin‐4(3H)‐ones 3 and 3,3′‐disubstituted bis‐2‐arylaminoquinazolin‐4(3H)‐ones 4 in good yields, respectively. To fully characterize the regioselectivity of aza‐Wittig reactions of 1‐aryl‐3‐(2‐ethoxycarbonylphenyl)carbo‐diimides with primary diamines, crystals of 4e were obtained, and its structure was determined by X‐ray crystallography.
Optimized palladium‐based approaches to analogues of PK 11195
Authors: Guillou Sandrine , Janin Yves L.
Published: March 2009

magnified image

The peripheral‐type benzodiazepine receptor ligands such as PK 11195 and Ro 5‐4864 were found more than twenty years ago in the course of research on neurobiology. These ligands were instrumental in pointing out an involvement of the peripheral‐type benzodiazepine receptor (PBR) in apoptosis processes. With in mind an improvement of the solubility of PK 11195 in biological media, we report here improved reaction conditions for the palladium‐based arylation reaction of alkyl 1‐bromoisoquinoline‐3‐carboxylates and its ethyl 4‐bromoquinoline‐2‐carboxylate isomer. The use of [1,1′‐bis(diphenylphosphino) ferrocene] dichloropalladium as a precatalyst enabled a much improved preparation of an array of the 1‐arylisoquinoline‐3‐carboxylates as well as 4‐arylquinoline‐3‐carboxylates. This work should pave the way for the design of chemical probes aiming at the elucidation of the PBR biological role(s).
Efficient regioselective synthesis of 4‐ and 5‐substituted isoxazoles under thermal and microwave conditions
Authors: Lasri Jamal , Mukhopadhyay Suman , Charmier M. Adflia Januário , Charmier M. Adflia Januário
Published: March 2009

magnified image

The [2+3] cycloaddition reaction between nitrile oxides 2 and the captodative olefins 1 or the methyl crotonate derivatives 4 is regioselective and leads to the formation of the 5‐substituted amino‐isoxazole 3 or the 4‐substituted methoxycarbonyl‐isoxazole 5 derivatives, respectively. All these reactions are greatly accelerated by microwave irradiation without changing their regioselectivity with respect to the thermal conditions.
Synthesis of 2‐imino‐7‐methyl‐2,3‐dihydroimidazo[1,2‐a]‐pyrimidin‐5(1H)‐ones and their reactions with nucleophiles
Authors: Jakubkiene Virginija , Kacnova Zana , Burbuliene Milda M. , Vainilavicius Povilas
Published: March 2009

magnified image

[2‐Alkylthio‐6‐methyl‐4‐oxopyrimidin‐3(4H)‐yl]acetonitriles (3‐5) treated with sodium methoxide in methanol followed by ammonium chloride were cyclized to 2‐imino‐7‐methyl‐2,3‐dihydroimidazo[1,2‐a]‐pyrimidin‐5(1H)‐ones (6‐8). Under acid or base‐catalyzed hydrolysis they were converted to 7‐methyl‐imidazo[1,2‐a]pyrimidine‐2,5‐[1H,3H]‐diones (9‐11), whereas in the reaction with butyl‐ or benzylamine the corresponding 7‐methyl‐2‐(substitutedamino)imidazo[1,2‐a]pyrimidin‐5(3H)‐ones (13‐18) were produced. The latter were found to exist in two tautomeric forms in CDCl3 solution.
Palladium‐catalyzed cyclization of 3‐bromopyridine‐4‐carbaldehyde with carbon monoxide and carboxylic acids
Authors: Cho Chan Sik , Uk Kim Jun
Published: March 2009

magnified image

3‐Bromopyridine‐4‐carbaldehyde is cyclized with carboxylic acids in acetonitrile at 100° under carbon monoxide pressure in the presence of a catalytic amount of a palladium catalyst along with a base to afford the corresponding 3‐oxo‐1,3‐dihydrofuro[3,4‐c]pyridine‐1‐yl alkanoates in moderate to good yields.
Synthesis of conformationally constrained adamantane imidazolines with trypanocidal activity
Authors: Papanastasiou Ioannis , Tsotinis Andrew , Foscolos George B. , Prathalingam S. Radhika , Kelly John M.
Published: March 2009

magnified image

Aiming at the development of new adamantano building blocks for treating African trypanosomiasis, we report on the synthesis of spiro adamantane 2‐imidazolines 8a‐f and 9a‐c, and their congeneric 5‐(1‐adamantyl)imidazolines 14 and 15. The potency of these compounds against Trypanosoma brucei was compared to that of rimantadine and found, in the case of compound 14e, to be three fold higher. Together with the other active compounds, 14b and 15b, which were equipotent to rimantadine, the new molecules illustrate the synergistic effect of the lipophilic character of adamantane and the C1 amidine functionality on trypanocidal activity.
Synthesis of boron macrocycles from 1,2‐aminoalcohols and 2‐formylphenylboronic acid
Authors: Appoh Francis A. , Barnes Stephanie S. , Manning Marcy J. , Turner Courtney S. , Vogels Christopher M. , Westcott Stephen A. , Decken Andreas
Published: March 2009

magnified image

Condensation of aminoalcohols with 2‐HC(O)C6H4B(OH)2 afforded the macrocyclic compounds 1–7 with an OBOBO structural unit. Crystals of 1 were triclinic, space group P‐1, a = 9.9818(12) Å, b = 12.8302(15) Å, c = 13.1663(15) Å, α = 105.503(2)°, β = 94.860(2)°, γ = 92.585(2)°, Z = 2.
Synthesis, structure and some reactions of 4a',5′,6′,7′,8′,8a'‐hexahydro‐4′H‐spiro[cyclohexane‐1,9′‐[1,2,4]triazolo[5,1‐b]‐quinazolines]
Authors: Chernyshev Victor M. , Khoroshkin Dmitry A. , Sokolov Andrey N. , Taranushich Vitaly A. , Gladkov Eugene S. , Shishkina Svetlana V. , Shishkin Oleg V. , Desenko Sergey M.
Published: March 2009

magnified image

2′‐Substituted 5′,6′,7′,8′‐tetrahydro‐4′H‐spiro[cyclohexane‐1,9′‐[1,2,4]triazolo[5,1‐b]quinazolines] 3a‐d were synthesized by condensation of 3‐substituted 5‐amino‐1,2,4‐triazoles 1a‐d with 2‐cyclohexylidene cyclohexanone 2 in DMF. The compounds 3 were hydrogenated with sodium borohydride in ethanol to give 2′‐substituted cis‐4a',5′,6′,7′,8′,8a'‐hexahydro‐4′H‐spiro[cyclohexane‐1,9′‐[1,2,4]triazolo[5,1‐b]quinazolines] 4a‐d in high yields. The reactions of alkylation, acylation and sulfonylation of the compounds 4 were studied. The structure of the synthesized compounds was determined on the basis of NMR measurements including HSQC, HMBC, NOESY techniques and confirmed by the X‐ray analysis of 6 and 11b. The described synthetic protocols provide rapid access to novel and diversely substituted hydrogenated [1,2,4]triazolo[5,1‐b]quinazolines.
Synthesis of potentially photoactivatable coumarin derivatives via a 1,3‐dipolar cycloaddition
Authors: Chenot Elodie‐Denise , Rodríguez‐Domínguez Juan Carlos , Comel Alain , Kirsch Gilbert , Hannewald Paul
Published: March 2009

magnified image

A copper (1)‐catalyzed 1,3‐dipolar cycloaddition reaction was used to prepare a series of mono and disubstituted 1,2,3‐triazolyl‐coumarins using a 1,3‐cycloaddition (“Click Chemistry”). Starting coumarins were synthesized using classical or modified Pechmann's reaction. The propargyl group was introduced as either propargylether or as a propargylamide. Azides were prepared in a three steps procedure. Cycloaddition products, containing a coumarin and a photoactivatable moiety, were obtained in good yields.
A general and efficient route to 6‐methyl‐pyrazin‐2‐yl‐amines: Alkylation of 2,6‐dichloropyrazine via malonate derivatives
Authors: Colbon Paul J. J. , Foster Alison C. , Giles Melvyn E. , Patel Zakariya , Singleton John T.
Published: March 2009

magnified image

We have developed a convenient two‐stage process for the synthesis of 6‐methylpyrazine‐2‐yl‐amines from commercially available materials. The procedure involves the synthesis of (6‐chloro‐pyrazin‐2‐yl)‐acetic acid via arylation of diethyl malonate and in situ hydrolysis/decarboxylation. A second decarboxylation takes place under the subsequent amination conditions allowing simple and efficient access to the intended pyrazines.
A simple one‐pot synthesis of 1,2,3,4‐tetrahydro‐2‐thioxopyrimidine derivatives
Authors: Akbał Esvet , Aslanoǧlu Furgan , Şener Ahmet , Anil Bariş
Published: March 2009

magnified image

5‐Benzoyl‐4‐(substituted phenyl)‐6‐phenyl‐1,2,3,4‐tetrahydro‐2‐thioxopyrimidines (4a‐d) were synthesized using the Biginelli three component cyclocondensation reaction of an appropriate β‐diketone, arylaldehyde, and thiourea in acetic acid under reflux condition in approximately 52‐65% yields. The acetylation of compounds 4a‐d gave 3‐acetyl thioxopyrimidine derivatives 5a‐d. Also, pyrimidothiazine compounds 6a‐d were prepared by a simple one‐pot condensation reaction of starting pyrimidine derivatives 4a‐d and 3‐bromopropionic acid. The structures of compounds were characterized on the basis of elemental analyses, IR, 1H and 13C‐NMR spectra.
Phosphomolybdic acid catalyzed facile one‐pot synthesis of 2,4,5‐triaryl‐1H‐imidazoles from benzil and aromatic aldehydes
Authors: Jadhav Siddheshwar D. , Kokare Nagnnath D. , Jadhav Sunil D.
Published: March 2009

magnified image

A facile one‐pot synthesis of 2,4,5‐triaryl‐1H‐imidazoles with better yields and shorter reaction time from the condensation of benzil, ammonium acetate and aromatic aldehydes using the catalyst phosphomolybdic acid is described
A new route to pyrimido[1,6‐a]benzimidazole derivatives
Authors: Bakavoli M. , Rahimizadeh M. , Ebrahimi A. R. , Taghizadeh A. , Davoodnia A. , Nikpour M.
Published: March 2009

magnified image

Cyclocondensation of orthophenylendiamines with 3‐bromopropionic acid in PPA afforded 2‐vinylbenzimidazoles which were subsequently converted to their corresponding 2‐(1,2‐dibromoethyl)‐1H‐benzimidazoles on treatment with bromine. Reaction of these compounds with aryl nitriles or aryl isocyanates in basic chloroform yielded 1‐arylpyrimido[1,6‐a]benzimidazoles and 2‐arylpyrimido[1,6‐a]‐benzimidazol‐3‐ones respectively.
Improved etherification procedure for the preparation of dibenz[b,f][1,4]oxazepine
Authors: Fakhraian H. , Nafary Y. , Yarahmadi A. , Hadj‐Ghanbary H.
Published: March 2009

magnified image

The effect of temperature and catalyst on the yield and rate of the etherification reaction between 1 and 2 was investigated and alternative methods for separation of 3 and 4 from the reaction mixture have been described.
A three‐component, one‐pot synthesis of oxazinoquinolin‐3‐one derivatives
Authors: Shakibaei Gazaleh Imani , Khavasi Hamid Reza , Mirzaei Peiman , Bazgir Ayoob
Published: March 2009

magnified image

Oxazino[5,6‐f]quinolin‐3‐one derivatives have been synthesized in a one‐pot, and efficient process by condensation of 6‐quinolinol, aromatic aldehydes and urea under microwave‐assisted and thermal solvent‐free conditions.
Synthesis and crystal structure of 5‐pyrazol‐4,5‐dihydropyrazoles derivatives
Authors: Xie Zhengfeng , Mo Xuexia , Liu Gang , Liu Fangming
Published: March 2009

magnified image

A series of 1‐acetyl(or phenyl)‐3‐aryl‐5‐(1‐phenyl‐3‐methyl‐5‐aryloxyl‐pyrazol)‐4,5‐dihydropyrazole derivatives have been efficiently synthesized under refluxing in glacial acetic acid with two kinds of hydrazines and five kinds of chalcones of 1‐phenyl‐methyl‐5‐phenoxyl‐pyrazol‐4‐aldehyde. The structures were confirmed on the basis of 1H NMR, IR, MS and element analysis, and the crystal structure of the compound 4c was determined by single crystal X‐ray diffraction. The compound 4c belongs to monoclinic system with space group P2(1)/n, a = 11.8779(3) nm, b = 12.0901(2) nm, c = 17.7004(4) nm, α = 90°, β = 100.05(10)°, γ = 90°, Formula weight: 549.46, Triclinic V = 2502.89(9) nm3, Dc = 1.458 Mg/m3, Z = 4, F (000) = 1128.
Sulfonic acid functionalized silica as an efficient heterogeneous recyclable catalyst for one‐pot synthesis of 2‐substituted benziimidazoles
Authors: Das Biswanath , Kanth Boddu Shashi , Reddy Kongara Ravinder , Kumar Avula Satya
Published: March 2009

magnified image

An efficient one‐pot synthesis of 2‐substituted benzimidazoles from o‐phenylenediamine and aldehydes in the presence of sulfonic acid functionalized silica at room temperature is reported.
Synthesis of new bis‐3,5‐diphenylpyrazolines derivatives linked with alkyl chains
Authors: Insuasty Braulio , Martinez Henry , Quiroga Jairo , Abonía Rodrigo , Nogueras Manuel , Cobo Justo
Published: March 2009

magnified image

New bis‐3,5‐diphenylpyrazoline derivatives have been synthesized according to Elway [1] (1999) and Sangwan's[2] (1992) methodology. Most of them were obtained in good yields, from the reaction between an alkyl linked bis‐chalcones and hydrazine in acetic acid. The activity of some bis‐pyrazolines was evaluated against Helicobacter pylori.
Synthesis of condensed pyridones by using a new ring switching reaction
Authors: Brunin Thierry , Rigo Benoît , Hénichart Jean‐Pierre
Published: March 2009

magnified image

A new ring‐switching reaction of enaminoesters behaving as bisnucleophiles towards other enaminoesters behaving as biselectrophiles is described. By starting from pyroglutamic derivatives, this reaction provided easy access to methyl 5‐oxo‐1,2,3,5‐tetrahydro‐3‐indolizinecarboxylates substituted by an aminoester side chain in position 6.
Synthesis and reactions of 3‐pyrrolidinones
Authors: Amer Fathy Abdel‐Kader , Hammouda Metwally , Abdel‐Wahab Bakr Fathy , El‐Ahl Abdel‐Aziz Sayed
Published: March 2009

magnified image

This review presents a survey of the synthetic methods and reactions of 3‐pyrrolidinonesI(R = H, alkyl, acyl, ester; R1= H, alkyl, cyano, ester, etc). 3‐Pyrrolidinones are synthetically versatiles substrate, as they can be used for synthesis of a large variety of heterocyclic compounds, such as indoles and 5‐deazapteroic acid analogues and as a raw material for drug synthesis. The high reactivity of an active methylene group next to the carbonyl of the pyrrolidine ring is useful for various syntheses.
The reaction of 2‐aroyl‐3,3‐bis(alkylsulfanyl)acrylaldehydes and hydroxylamine hydrochloride: Facile synthesis of differently substituted isoxazoles
Authors: Mathews Annie , Sasikala Karunalayam A. , George Sholly C. , Krishnaraj Kooramattom U. , Sreedevi Naduthottiyil K. , Prasanth Marathu , Anabha Engoor R. , Devaky Karakkattu S. , Asokan Chittoorthekkathil V.
Published: March 2009

magnified image

2‐Aroyl‐3,3‐bis(alkylsulfanyl)acrylaldehyde was utilized for the synthesis of three different isoxazoles by reacting with hydroxylaminehydrochloride. We synthesized differently substituted isoxazoles like (aryl)[5‐(methylsulfanyl)‐4‐isoxazolyl]methanones, 3‐(methylsulfanyl)‐5‐phenyl‐4‐isoxazolecarbonitriles and 5‐aryl‐3‐(methylsulfanyl)‐4‐isoxazolecarbaldehyde oximes in good yields by varying the substratereagent stoichiometry and temperature of the reaction medium.
Facile synthesis ofN‐α‐boc‐1,2‐dialkyl‐l‐histidines: Utility in the synthesis of thyrotropin‐releasing hormone (trh) analogs and evaluation of the cns activity
Authors: Monga Vikramdeep , Meena Chhuttan Lal , Kaur Navneet , Kumar Satyendra , Pawar Chandrashekhar , Sharma Shyam Sunder , Jain Rahul
Published: March 2009

magnified image

A facile synthesis ofN‐α‐Boc‐1,2‐dialkyl‐L‐histidines starting fromN‐α‐trifluoroacetyl‐L‐histidine methyl ester is reported. The key steps involve direct and regiospecific N‐1(τ) ring‐alkylation of theN‐α‐trifluoroacetyl‐L‐histidine‐methyl ester by suitable alkyl iodide in the presence of NaH in DMF at −15 °C followed by homolytic free radical C‐2 alkylationviaa silver catalyzed oxidative decarboxylation of alkylcarboxylic acid in the presence of ammonium persulfate under acidic conditions. The application of newly synthesized bioimidazoles was illustrated by their incorporation into thyrotropin‐releasing hormone (TRH). The synthesized TRH analogs were evaluatedin vivofor analeptic activity. We report discovery of a TRH analog, which was found to potentiate the pentobarbital‐induced sleepin vivo.
Solvent‐free synthesis of 5‐methyl‐7‐aryl‐4,7‐dihydrotetrazolo[1,5‐a]pyrimidine‐6‐carboxylic esters catalyzed by sulfamic acid
Authors: Yao Changsheng , Lei Song , Wang Cuihua , Yu Chenxia , Tu Shujiang
Published: March 2009

magnified image

The solvent‐free synthesis of 5‐methyl‐7‐aryl‐4,7‐dihydrotetrazolo[1,5‐a]pyrimidine‐6‐carboxylic esters was performed and effectively catalyzed by sulfamic acid. Compared with conventional methods, this protocol features mild reaction conditions and high yields. Furthermore, it is solvent‐free and thus eco‐friendly.
Synthesis of 2,4‐disubstituted 6‐phenyl‐7H‐pyrrolo[3,2‐d]‐pyrimidin‐7‐one 5‐oxides
Authors: Cikotiene Inga , Pudziuvelyte Erika , Brukstus Algirdas
Published: March 2009

magnified image

A relatively short and efficient method for the utilization of 4,6‐dichloro‐2‐methylthio‐5‐nitropyrimidine (1) in the synthesis of the poly substituted pyrrolo[3,2‐d]pyrimidin‐7‐one 5‐oxides (6a‐g) is reported. Some new 4‐substituted 6‐chloro‐2‐methylthio‐5‐nitropyrimidines (2a‐e) were prepared by reaction of 4,6‐dichloro‐2‐methylthio‐5‐nitropyrimidine (1) with amines. 4‐Substituted 2‐methylthio‐5‐nitro‐6‐phenylethynylpyrimidines (3a‐e), obtained from 4‐substituted 6‐chloro‐2‐methylthio‐5‐nitropyrimidines (2a‐e) via palladium‐catalyzed Sonagashira coupling reaction with 1‐phenylacetylene, underwent smooth cyclization reaction in boiling 2‐propanol in the presence of catalytic amount of pyridine to give 4‐substituted 2‐methylthio‐6‐phenyl‐7H‐pyrrolo[3,2‐d]pyrimidin‐7‐one 5‐oxides (4a‐e). The methylthio group of the latter compounds can be easily and selectively oxidized by m‐chloroperbenzoic acid and replaced with different amines.
Michael adducts of vinyl sulfones — source for thiadiazoles, oxadiazoles and triazoles
Authors: Padmavathi Venkatapuram , Reddy Guda Dinneswara , Reddy Gali Sudhakar
Published: March 2009

magnified image

A new and novel five membered heterocycles thiadiazoles, oxadiazoles and triazoles were prepared from methyl 4‐arylsulfonyl‐3‐arylbutyrate and methyl 4‐arylmethanesulfonyl‐3‐arylbutyrate.
Microwave‐assisted synthesis of new regioisomeric 6,7‐dihydroindeno[1,2‐e]pyrimido[4,5‐b][1,4]diazepin‐5(5aH)‐ones
Authors: Insuasty Braulio , Orozco Fabián , Garcia Angélica , Quiroga Jairo , Abonia Rodrigo , Nogueras M. , Cobo Justo
Published: March 2009

magnified image

Novel 11‐amino‐6‐aryl‐6,7‐dihydroindeno[1,2‐e] pyrimido[4,5‐b][1,4]diazepin‐5(5aH)‐ones 4a‐f were prepared regioselectively by the tricomponent reaction of 4,5,6‐triaminopyrimidine 1, 1,3‐indandione 2 and aromatic aldehydes 3a‐f. The bicomponent approach, using 2,4,5,6‐tetraaminopyrimidine 5 and 2‐aryl‐ideneindandiones 6a‐f as reagents, afforded 9,11‐diamino‐6‐aryl‐6,7‐dihydroindeno[1,2‐e]pyrimido[4,5‐b]‐[1,4]diazepin‐5(5aH)‐ones 7a‐f in good yields and the regioisomeric 8,10‐diamino derivatives 8a‐c in lower yields. Both, bi‐ and tricomponent approaches were performed by microwave irradiation and all products were fully characterized by detailed NMR measurements.
1,3,2‐(2H)‐dioxaborine polymethine dyes on the base of dehydroacetic acid — effective fluorescent amine probes
Authors: Gerasov Andriy O. , Shandura Mykola P. , Kovtun Yuriy P. , Vlasenko Yuriy G. , Gorchev Vasyliy F.
Published: March 2009

magnified image

A number of new polymethine dyes based on the boron difluoride complexes of dehydroacetic acid and 3‐acetyl‐4‐hydroxypyridone has been synthesized. Their spectral‐luminescent properties have been investigated. The reaction of obtained merocyanines with primary and secondary amines has been studied. These low fluorescent dyes gave highly fluorescent open chain products, which on further heating cyclized to weakly fluorescent pyridone dyes.
A facile one pot synthesis of 2, 4‐diamino‐6‐substituted s‐triazine derivatives
Authors: Sathunuru Ramadas , Melendez Victor , Kozar Michael P. , Lin Ai J.
Published: March 2009

magnified image

A novel and facile one‐pot procedure for the preparation of 2,4‐diamino‐6‐substituted‐s‐triazine derivatives (IIa‐n) was reported. The scope of its application was demonstrated with a number of examples. The new procedure involved treatment of proguanil or chloroproguanil with acyl chloride or alky chlorooxoacetate in pyridine at ice cold temperature followed by reflux overnight to give good yields of the desired products.
Ring closure reactions of 5‐azidopyrido[2,3‐d]pyrimidinetriones to isoxazolo‐ and oxadiazolopyrido[2,3‐d]pyrimidinetriones
Authors: Van Tinh Dang , Stadlbauer Wolfgang
Published: March 2009

magnified image

Thermal decomposition of 5‐azidopyrido[2,3‐d]pyrimidines 2 and 7 having reactive ortho‐substituents such as a formyl or a nitro group yielded isoxazolo[3′,4′:4,5]pyrido[2,3‐d]pyrimidines 3 or oxadiazolo‐[3′,4′:4,5]pyrido[2,3‐d]pyrimidines 9. The reaction conditions of the azide decomposition were studied by differential scanning calorimetry (DSC). In addition, desoxygenation of N‐oxides 9 to oxadiazoles 10 and regioselective reduction of azides 7 to amines 8 were studied.
Application of the acetate of baylis‐hillman adducts of salicylaldehydes in the synthesis of methyl 2‐oxo‐2,3‐dihydrobenzo[b]oxepine‐4‐carboxylates
Authors: Ahn Sang‐Hyun , Lim Hee Nam , Lee Kee‐Jung
Published: March 2009

magnified image

A simple synthesis of several methyl 2‐oxo‐2,3‐dihydrobenzo[b]oxepine‐4‐carboxylates from Baylis‐Hillman adducts of O‐benzyl protected 2‐hydroxybenzadehydes has been described through the acetylation, cyanation, debenzylation, as well as acid assisted Pinner cyclization.
Synthesis of new 1‐[4‐methane(amino)sulfonylphenyl)]‐5‐[4‐(aminophenyl)]‐3‐trifluoromethyl‐1H‐pyrazoles
Authors: Abdellatif Khaled R. A. , Chowdhury Morshed A. , Knaus Edward E.
Published: March 2009

magnified image

A regiospecific cyclization‐dehydration reaction of a 1‐[(4‐(N‐alkyl‐N‐(tert‐butyloxycarbony)amino)‐phenyl]‐4,4,4‐trifluorobutane‐1,3‐done with a 4‐aminosulfonyl‐, or 4‐methylsulfonyl‐, phenylhydrazine hydrochloride in refluxing ethanol proceeded with simultaneous loss of the N‐tert‐butyloxycarbonyl protecting group to afford a group of 1‐(4‐methanesulfonylphenyl or 4‐aminosulfonylphenyl)‐5‐[4‐(N‐alkylaminophenyl)]‐3‐(trifluoromethyl)‐11H‐pyrazoles(6). Subsequent reaction of the pyrazole 6 (R1 = R2 = Me) with nitric oxide (40 psi) proceeded via a N‐methylamino‐N‐diazen‐1‐ium‐1,2‐diolate intermediate that undergoes protonation of the more basic diazen‐1‐ium‐1,2‐diolate N2‐nitrogen and then loss of a nitroxyl (HNO) species to furnish the N‐nitroso product 7.
Studies in synthesis of furoflavones possessing anti‐cancer activity
Authors: Patel Jagdish M. , Soman Shubhangi S.
Published: March 2009

magnified image

Several new furoflavanones (3a‐3I) have been synthesized from the in‐situ generated chalcones by the reaction of ortho‐hydroxy acetyl benzofuran and aryl aldehyde in presence of piperidine. Ethanolic sodium hydroxide (1%) gave chalcones (2a‐2I) as the exclusive product. Flavindogenides (3‐arylidene flavanones) (5a‐5d) have been isolated as the co‐product along with chalcones and flavanones in cases where excess of aryl aldehyde was used. The stereochemistry of 3‐arylidene flavanones has been established by the preparation of both Z (6) and E (5a‐5d) diastereomers. Single crystal X‐ray diffraction data shows the flavanone ring to exist in quasi chair conformation with phenyl ring equatorial. Furoflavanones were finally dehydrogenated to furoflavones (4a‐4I) using DDQ (2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone). The compounds have been screened for in‐vitro cytotoxicity against human cancer cell lines.
Gas‐phase pyrolysis in organic synthesis: New route for synthesis of functionally substituted imidazoles
Authors: El‐Dusouqui Osman M. E. , Al‐Awadi Nouria A. , Elnagdi Mohamed H. , Abdelkhalik Mervat M.
Published: March 2009

magnified image

1,2,3‐Triazolylpropanone was prepared and coupled with aryldiazonium salts yielding the corresponding arylhydrazones. Gas‐phase pyrolysis of the hydrazono derivative produced N‐arylamino‐2‐acetylimidazole as well as 2‐acetylimidazole. The latter is the product of further pyrolysis of the former.
Synthesis and biological activities of novel chiral fluorinated β‐carboline derivatives
Authors: Ding Jin Chang , Huang Xiao Bo , Wu Hua Yue , Chen Jie Zhi , Cai Ming Tiao , Liu Miao Chang
Published: March 2009

magnified image

A series of unreported chiral β‐carbolines 4 with trifluoromethyl group at position‐1 and chiral carboxamide chains or amino acid ester chains at position‐3 has been designed and synthesized. The results of bioassay in vitro show that compounds 4e, 4i and 4k show 78.8%, 84.0% and 78.9% inhibition on monoamine oxidase, in 1 mmol/L, respectively, and compound 4e also exhibit 60.9% inhibitory activity on tumor lung cell A‐549 in 10−5 mmol/L. In view of different configuration, the inhibitory activity on monoamine oxidase of S‐enantiomer of the target compound is better than that of R‐enantiomer.
Formation of aryl‐bis (6‐amino‐1,3‐dimethyluracil‐5‐yl) methanes by reaction of 6‐amino‐1, 3‐dimethyluracil with aromatic aldehydes
Authors: Bansal Ranju , Kumar R. Sunil , Kumar Gulshan , Thota Sridhar , Thamotharan S. , Parthasarathi V. , Linden Anthony
Published: March 2009

magnified image

The synthesis of aryl‐bis(6‐amino‐1,3‐dimethyluracil‐5‐yl)‐methanes 3a‐m by condensation of 6‐amino‐1,3‐dimethyluracil (1) with aromatic aldehydes 2a‐m at room temperature is reported. The structures of the compounds were established using various spectroscopic analyses and X‐ray crystallography. The crystal structures of two aryl‐bis (6‐amino‐1,3‐dimethyluracil‐5‐yl) methanes are presented.
An efficient synthesis of quinoxaline derivatives mediated by stannous chloride
Authors: Shi Da‐Qing , Dou Guo‐Lan , Ni Sai‐Nan , Shi Jing‐Wen , Li Xiao‐Yue
Published: March 2009

magnified image

Various biologically important quinoxaline derivatives were efficiently synthesized in excellent yields by the reaction of 1,2‐diketones and 2‐nitroaniline, benzofuroxan or 1,2‐dinitrobenzene promoted by SnCl22H2O. The role of stannous chloride is acting as both reductive agent and catalyst in this synthesis. This new method has the advantages of accessible starting materials, convenient manipulation, short reaction time and high yields.
Synthesis of the indole core structures of conophylline
Authors: Ando Shin , Okamoto Yoshinari , Otsuka Masami , Umezawa Kazuo
Published: March 2009

magnified image

Conophylline is a bisindole alkaloid of unique structure that shows anti‐cancer and anti‐diabetic activities. Two indole core structures of conophylline, namely 6,7‐dimethoxy‐5‐methoxymethoxy‐1H‐indole (1), and N‐benzoyl‐N‐[2‐(6‐methoxymethoxy‐2‐vinyl‐1H‐indol‐3‐yl)ethyl]amine (2) has been synthesized starting with substituted benzene derivatives.
N‐Arylation of N‐H heterocycles with aryl bromides and aryl iodides using cui and kf/Al2O3
Authors: Hosseinzadeh Rahman , Tajbakhsh Mahmood , Alikarami Mohammad , Mohadjerani Maryam
Published: March 2009

magnified image

Copper‐catalyzed system for N‐arylation of N‐H group in heterocycles such as indole, pyrrole and carbazole with aryl iodides and aryl bromides using potassium fluoride supported on alumina as a base is described. This is a simple and efficient method for the coupling of aryl iodides and bromides with N‐H heterocycles. Different functionalized iodo and bromo arenes were coupled with N‐H heterocycles using this system.
Solvent‐free one‐pot approach for synthesis of substituted 2‐aminochromenes
Authors: Zhou Dong , Ren Zhongjiao , Chen Jie , Cao Weiguo , Deng Hongmei
Published: March 2009

magnified image

A solvent‐free one‐pot approach for the preparation of 2‐aminochromenes in the presence of NaHCO3 by grinding was described. Its advantages are easy work‐up, mild reaction condition, high yield and environmental compatibility.
Vicarious nucleophilic amination of nitroquinolines by 1,1,1‐trimethylhydrazinium iodide
Authors: Grzegożek Maria
Published: March 2009

magnified image

The amination of 3‐, 5‐, 6‐, 7‐ and 8‐nitroquinoline via the vicarious nucleophilic substitution of hydrogen (VNS) with 1,1,1‐trimethylhydrazinium iodide (TMHI) in the presence of t‐BuOK in DMSO was studied. The amination occurs regioselectively giving ortho or ortho and para isomers relative to the nitro group with a high yield (95‐86%). 2‐Nitroquinoline does not undergo vicarious amination but displacement of the labile nitro group by an amino group occurs and then transformation to an imine compound and hydrolysis gives2(1H)‐quinolinone.
Synthesis and DNA‐binding properties of 1,10‐phenanthroline analogues as intercalating‐crosslinkers
Authors: Higashi Toshinori , Inami Keiko , Mochizuki Masataka
Published: March 2009

magnified image

We synthesized a series of bis(bromomethyl)‐1,10‐phenanthrolines as novel anticancer lead compounds and examined their DNA‐binding properties. 5,6‐Bis(bromomethyl)‐1,10‐phenanthroline showed DNA intercalating activity and DNA crosslinking activity, furthermore it is stable in aqueous solution.
Post‐offence characteristics of 19th‐century American parricides: An archival exploration
Authors: Shon Phillip C. , Roberts Michael A.
Published: March 2009

Using archival records from the New York Times and the Chicago Tribune, 1851–1899, the current project examines the post‐offence characteristics of 19th‐century American parricides. Post‐offence behaviours of 100 parricide offenders were gathered. Results indicate that post‐offence behaviours of parricide offenders can be thematically classified into those that reflect a continuity of violence, attempts to cover up the crime, and unusual behaviours. The implications of post‐offence behaviours of parricide offenders in the context of law, mental illness, and criminological theory are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and evaluation of two uncharged 99mTc‐labeled derivatives of thioflavin‐T as potential tracer agents for fibrillar brain amyloid
Authors: Serdons K. , Vanderghinste D. , Van Eeckhoudt M. , Cleynhens J. , de Groot T. , Bormans G. , Verbruggen A.
Published: March 2009

Thioflavin‐T is a fluorescent dye for in vitro detection of fibrillar amyloid β, a protein found in the brain of patients suffering from Alzheimer's disease. We synthesized and biologically evaluated two uncharged 99mTc‐labeled derivatives of thioflavin‐T. The precursors for labeling were synthesized by coupling an S,S′‐bis‐triphenylmethyl‐N‐tert‐butoxycarbonyl bis‐amino‐bis‐thiol tetradentate ligand via a propoxy spacer to 2‐(4′‐aminophenyl)‐1,3‐benzothiazole at the 6‐position or the 2′‐position. Deprotection and labeling with 99mTc were done via a one‐pot procedure (15% yield) after which the labeled compound was isolated by high performance liquid chromatography (LC). LC in combination with mass spectrometry (MS) was used for identity confirmation of the labeled compounds. Results of electrophoresis and log P determination supported the assumption that the radiolabeled compounds could cross the blood–brain barrier by passive diffusion. However, in normal mice both compounds showed a low brain uptake 2 min post injection. They were mainly excreted through the hepatobiliary system, with some accumulation in the stomach. Sixty minutes after intravenous injection, 37% of the 99mTc‐activity in the blood corresponded to the original compound. In view of the low brain uptake, it is concluded that the studied 99mTc‐labeled derivatives of thioflavin‐T are not suitable as tracer agents for in vivo visualization of amyloid in brain. Copyright © 2009 John Wiley & Sons, Ltd.
Syntheses of deuterium labelled atropine and scopolamine
Authors: Balssa Frédéric , Bonnaire Yves
Published: March 2009

Easy preparative scale syntheses of deuterium labelled atropine and scopolamine are described. [2H3]‐atropine and [2H3]‐scopolamine are obtained in good yield and good isotopic purity in two steps starting from the unlabelled alkaloids. Copyright © 2009 John Wiley & Sons, Ltd.
Recognition and palaeoclimatic implications of late Quaternary niche glaciation in eastern Lesotho
Authors: Mills Stephanie C. , Grab Stefan W. , Carr Simon J.
Published: March 2009

Geomorphic evidence of former glaciation in the high Drakensberg of southern Africa has proven controversial, with conflicting glacial and non‐glacial interpretations suggested for many landforms. This paper presents new geomorphological, sedimentological and micromorphological data, and glacier mass‐balance modelling for a site in the Leqooa Valley, eastern Lesotho, preserving what are considered to be moraines of a former niche glacier that existed during the Last Glacial Maximum (LGM). The geomorphology and macro‐sedimentology of the deposits display characteristics of both active and passive transport by glacial processes. However, micromorphological analyses indicate a more complex history of glacial deposition and subsequent reworking by mass movement processes. The application of a glacier reconstruction technique to determine whether this site could have supported a glacier indicates a reconstructed glacier equilibrium line altitude (ELA) of 3136 m a.s.l. and palaeoglacier mass balance characteristics comparable with modern analogues, reflecting viable, if marginal glaciation. Radiocarbon dates obtained from organic sediment within the moraines indicate that these are of LGM age. The reconstructed palaeoclimatic conditions during the LGM suggest that snow accumulation in the Drakensberg was significantly higher than considered by other studies, and has substantial relevance for tuning regional climate models for southern Africa during the last glacial cycle. Copyright © 2009 John Wiley & Sons, Ltd.
Oligoagarose‐Graft‐Polycaprolactone Copolymers: Synthesis and Characterization
Authors: Bhaw‐Luximon Archana , Jhurry Dhanjay , Booluck Mooneerah Heerah , Correc Gaëlle , Génicot Sabine , Helbert William
Published: March 2009

In this paper, we combine hydrophilic oligoagarose (DPn = 10–15), issued from enzymatic degradation of the natural biopolymer agarose, with polycaprolactone, a synthetic biodegradable and hydrophobic polyester. To synthesize these amphiphilic graft copolymers, we use partially acetylated oligoagarose as macroinitiator in combination with tin (II) octanoate for the bulk polymerization of ε‐caprolactone. The grafting was confirmed by NMR and SEC which showed a monomodal distribution. After removal of the acetyl protecting groups, copolymers with 30–60% free hydroxyl groups were soluble in water and insoluble in chloroform, thus indicating that they probably adopt micelle‐like structures in aqueous solution with a PCL hydrophobic core and spherical oligoagarose side chains.
Rheological Hybrid Effect and its Conditions in Filled Polymer Melts
Authors: He Jiasong
Published: March 2009

In contrast to usually increased viscosity of filled polymer melts with increasing filler content, some filled polymer melts showed decreased melt viscosity in the presence of thermotropic (main chain) liquid crystalline polymer (LCP) with increasing filler content. This phenomenon was termed as rheological hybrid effect and found correlated well with the fibrillation of LCP melt droplets. Investigation of this LCP fibrillation in matrix polymers, with fillers of various shapes at micro‐ and nano‐meter scales, showed that LCP fibrillation was promoted by the filler addition, depending upon thermodynamic and hydrodynamic driving forces involved.
Vibrational Dynamics, Phonon Dispersion and Specific Heat in Gas Permeable Poly(4‐Methyl‐2‐Pentyne)
Authors: Kumar Anuj , Pathak Sapna , Singh Mahendra , Tandon Poonam , Gupta V. D.
Published: March 2009

Poly(4‐methyl‐2‐pentyne) (PMP) is an amorphous glassy disubstituted acetylene based polymer. The excellent gas‐separation and mechanical properties of these polymers have stipulated their use as membrane material for vapor and gas separation. PMP is among the hydrocarbon disubstituted polyacetylenes which have been synthesized to date. This polymer combines excellent gas and vapor permeability with good resistance to organic solvents. As was shown recently, PMP offers promise in the manufacture of nanocomposite membranes for the separation of various hydrocarbon mixtures. It is also of importance as its monomer, 4‐methyl‐ 2‐pentyne, can be easily derived from commercial compounds, 4‐methyl‐2‐pentene or methyl isobutyl ketone, produced on a large scale. It is known that PMP exists in cis and trans configurations. Synthetic conditions, e.g., the used catalyst, temperature, solvent etc., of substituted polyacetylenes decide percentage of different configurations (cis or trans). Different geometries of macromolecules can influence the supramolecular structure of the polymer, which primarily defines its properties, such as solubility, permeability, sorption, etc. Qualitative assignments of few bands of IR spectra are reported earlier. We present here, complete normal mode analysis and dispersion curves for PMP using Wilson GF matrix method modified by Higgs using Urey‐Bradley force field. Dispersion curves for PMP are drawn and salient features are discussed. Predicted values of specific heat via density‐of‐states are also reported.
Synthesis and Characterization of Polysulfide Rubber Using Phase Transfer Catalyst
Authors: Kalaee M. R. , Famili M. H. N. , Mahdavi H.
Published: March 2009

Summary: Poly(alkyltetrasulfide) is prepared via reaction of ethylene dichloride with sodium tetrasulfide (Na2S4) in the presence of methyl tributyl ammonium chloride as phase transfer catalyst (PTC). The polysulfide polymer is characterized by CHN analysis, FT‐IR, TGA, DTA and DSC techniques.
Growth and Thermal, Electrical, Structural Characterization of Mixed Hydrated Single Crystal
Authors: Naware S. P. , Kelkar D. S.
Published: March 2009

Mixed single crystal was made by mixing saturated aqueous solutions of NiSO4 · 6H2O and CuSO4 · 5H2O by volume (80:20) and the mixture was kept to form the crystals at room temperature by slow evaporation process. After some days, big pieces of greenish blue, dark colored crystals were grown. To determine the weight of NiSO4 · 6H2O and CuSO4 · 5H2O in the crystal, Ni‐DMG complexiometrical and EDTA gravimetrical analysis was done respectively. From this analysis it was concluded that 5.8 molecules of water of crystallization is present in the mixed single crystal. The crystals were characterized by UV‐Visible, FTIR and single crystal X‐ray diffraction studies. From single crystal XRD lattice parameters have been calculated. All these structural analysis confirms formation of new single crystal. Further, DTA‐TGA, dc electrical conductivity and dielectric constant studies were done from the room temperature to 400 °C.From DTA studies it was observed that 5.8 molecules of water of crystallization get dehydrated in four major steps at temperature 115 °C, 150 °C, 240 °C and 325 °C respectively corresponding to the detachment of 1 mole, 3 moles, 1 mole and 0.8 mole of water of crystallization. DC electrical conductivity and dielectric constant studies also show close agreement to the dehydration steps. The observed peaks in the conductivity verses temperature graph have been explained on the basis of release of water molecules and subsequent dissociation of these released water molecules into H+ and OH− ions.
Photophysical and Electrochemical Investigations on Photoconducting Poly(6‐tert‐butyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine)
Authors: Dhanya R. , Kishore V. C. , Sreekumar K. , Kartha C. Sudha , Joseph Rani
Published: March 2009

Poly(6‐tert‐butyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine) was synthesized by thermally activated cationic ring opening polymerization. The structure of the polymer was confirmed by spectral and thermal studies. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were estimated using cyclic voltammetry and optical absorption. Modulated photocurrent measurement technique was employed to study the spectral and field dependence of photocurrent. Photocurrent of the order of 1.5 µA/m2 was obtained for polymer at a biasing electric field of 40 V/µm.
Modification of Polypropylene/Glass Fiber Composites with Nanosilica
Authors: Jacob Sinto , Suma K. K. , Mendaz Jude Martin , George Abhilash , George K. E.
Published: March 2009

Poly(propylene) (PP) reinforced with short glass fiber was modified with precipitated nanosilica (pnS) by melt mixing. The weight of the glass fiber was varied by keeping the pnS at optimum level. The properties of the composites were studied using universal testing machine, dynamic mechanic analyser (DMA), differential Scanning calorimetry (DSC) and thermo gravimetric analyser (TGA). The amount of the glass fiber required for a particular modulus could be reduced by the addition of nanosilica.
Paint Formulation Using Water Based Binder and Property Studies
Authors: Suma K. K. , Jacob Sinto , Joseph Rani
Published: March 2009

Vinyl acetate – Butyl acrylate (VAc‐BuA) copolymer latices of various compositions were prepared by semicontinuous emulsion polymerization. The copolymer formed after removing the homopolymers was characterized by FTIR spectroscopy. Mechanical properties were studied by Universal Testing machine. Differential scanning calorimetry (DSC) study of copolymer showed single glass transition temperature (Tg) value confirming the absensce of graft and block copolymer. These copolymer latices were used as the binder in water based latex paint formulation. The paint prepared using 85/15 wt.% of VAc‐BuA was found to give a better paint properties. Water based paints are generally easier to apply and clean up. The surface properties found to be superior compared to commercially used paint.