bluuebunny/crossref_metadata_2025_split 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

Abstractmagnified imageSynthesis 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

Abstractmagnified imageA 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

Abstractmagnified image3‐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

Abstractmagnified imageA 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

Abstractmagnified imageFree‐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

Abstractmagnified imageStaudinger 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

Abstractmagnified imageThe 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

Abstractmagnified image1‐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

Abstractmagnified imageThe 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

Abstractmagnified imageThe [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

Abstractmagnified 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

Abstractmagnified image3‐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

Abstractmagnified imageAiming 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

Abstractmagnified imageCondensation 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

Abstractmagnified image2′‐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

Abstractmagnified imageA 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

Abstractmagnified imageWe 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

Abstractmagnified image5‐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

Abstractmagnified imageA 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

Abstractmagnified imageCyclocondensation 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

Abstractmagnified imageThe 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

Abstractmagnified imageOxazino[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

Abstractmagnified imageA 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

Abstractmagnified imageAn 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

Abstractmagnified imageNew 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

Abstractmagnified imageA 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

Abstractmagnified imageThis 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

Abstractmagnified image2‐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

Abstractmagnified imageA 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

Abstractmagnified imageThe 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

Abstractmagnified imageA 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

Abstractmagnified imageA new and novel five membered heterocycles thiadiazoles, oxadiazoles and triazoles were prepared from methyl 4‐arylsulfonyl‐3‐arylbutyrate and methyl 4‐arylmethanesulfonyl‐3‐arylbutyrate.