bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of a novel water‐soluble NMDA receptor antagonist
Authors: Masuko Takashi , Kusama Tadashi , Nagaoka Hiroki , Metori Koichi , Kizawa Yasuo , Miyake Muneharu 
Published: March 2009

Abstractmagnified imageA novel water‐solubleN‐methyl‐D‐aspartate (NMDA) receptor antagonist ATGDMAP1as synthesized and the effect of1on NMDA receptors was studied using voltage‐clamp recordings of recombinant NMDA receptors expressed inXenopusoocytes. The compound1inhibited macroscopic currents in NR1/NR2A, NR1/NR2B, NR1/NR2C and NR1/NR2D receptor subtypes in oocytes voltage‐clamped at ‐70 mV. Mutant NR1/NR2B receptors containing NR1(T648A) or NR1(T648S) had very large holding currents when voltage‐clamped at ‐70 mV compared to that of wild‐type NMDA receptors, because these mutants generate constitutively open channels. ATGDMAP1and Mg2+, a channel blocker of the NMDA receptor, reduced the large holding currents needed for mutant NMDA receptors. These data indicate that ATGDMAP1directly acts on the channel pores of the NMDA receptor.
The synthesis and fluorescence of novel N‐substituted‐1,8‐naphthylimides
Authors: Yuan Dongwu , Brown Robert G , Hepworth John D , Alexiou Michael S , Tyman John H. P. 
Published: March 2009

Abstractmagnified imageThe synthesis and characterisation of a series of novel 4‐acylamino and 4‐alkylamino‐N‐1,8‐naphthalimides is described. The UV‐visible absorption and emission properties of the compounds are reported. Significant solvent effects are noted for 4‐n‐butyl‐9‐n‐butyl‐1,8‐naphthylimide. The incorporation of acetyl and chloroacetyl groups into the 4‐substituent markedly increases the fluorescence quantum yield compared with 4‐alkylamino substituemnts.
Green and high efficient synthesis of triaza‐benzo[b]fluoren‐6‐one derivatives in water under microwave irradiation
Authors: Shao Qingqing , Tu Shujiang , Li Chunmei , Cao Longji , Zhou Dianxiang , Jiang Bo , Zhang Yan , Hao Wenjuan , Wang Qian 
Published: March 2009

Abstractmagnified imageTriaza‐benzo[b]fluoren‐6‐one derivatives were synthesized via the three‐component reaction of aldehyde, cyclohexane‐1,3‐dione compound and 2‐aminobenzimidazole in water under microwave irradiation. The new protocol has the advantages of excellent yield, low cost, reduced environment impact, wide scope and convenient procedure.
New route for preparation of nitrosubstituted 1,2‐phenylenediamines
Authors: Bella MaroŠ , Milata Viktor 
Published: March 2009

Abstractmagnified image4‐Nitrobenzoselenadiazole was methylated with dimethylsulphate to give corresponding 1‐N‐methyl‐4‐nitrobenzoselenadiazolium methylsulphate which after alkaline ring‐opening afforded 1‐N‐methyl‐3‐nitro‐1,2‐phenylenediamine in 90% yield. This compound was also prepared from 3‐nitro‐1,2‐phenylenediamine by monomethylation through tosylation, methylation and detosylation and was confirmed and characterised as 1‐methyl‐4‐nitrobenzimidazole. Methylation of 5‐nitrobenzoselenadiazole and subsequent alkaline ring‐opening led to unseparable mixture of both methylated products.
Synthesis of 1,3‐oxazole and benzimidazole pendant groups from polyacrylonitrile hydrolysis products
Authors: Vega Isabel N. , Sánchez Leonardo , D'Accorso Norma 
Published: March 2009

Abstractmagnified imageNew terpolymers containing heterocyclic pendant groups, such as 1,3 oxazole and benzimidazole are obtained by hydrolysis of polyacrylonitrile (PAN). These materials are spectroscopically characterized and their solubility, viscosity and thermal behavior are analyzed.
Kinetic study ofmeso‐tetraphenylporphyrin synthesis under microwave irradiation
Authors: De Paula Rodrigo , Faustino Maria A. F. , Pinto Diana C.G.A. , Neves Maria G.P.M.S. , Cavaleiro José A. S. 
Published: March 2009

Abstractmagnified imageA typical synthesis ofmeso‐tetraphenylporphyrin was carried out from condensation of pyrrole with benzaldehyde in acidic medium under microwave irradiation. A batch of tests were carried out and a systematic evaluation of organic acid, reactant concentration, microwave power, time of reaction, presence of added oxidant at normal pressure conditions and in closed vessels system, allowed us to find a good set of conditions within the range of study. The best result was achieved in only 5 minutes of irradiation showing a great reduction in reaction time and reaching yields higher than those mentioned in literature for the synthesis under classical synthetic heating method.
Synthesis of 2,4‐difuryl‐4H‐3,1‐benzothiazines via a furan ring migration reaction
Authors: Abaev Vladimir T. , Tsiunchik Fatima A. , Butin Alexander V. , Gutnov Andrey V. 
Published: March 2009

Abstractmagnified imageA new simple synthetic approach to 2,4‐difuryl‐4H‐3,1‐benzothiazines from 2‐isothiocyanoaryldifuryl‐methanes in the presence of acidic catalyst is described. This rearrangement is a new example of furan ring migration reaction resulting from intramolecular attack with electrophilic carbon.
High pressure‐assisted synthesis of 1,2,3‐trialkyldiaziridines from N‐chloroalkylamines
Authors: Kuznetsov Vladimir V. , Syroeshkina Julia S. , Moskvin Dmitrii I. , Struchkova Marina I. , Makhova Nina N. , Zharov Alexey A. 
Published: March 2009

Abstractmagnified imageNew method for the preparation of 1,2,3‐trialkyldiaziridines 1 in high yields, based on the transformation of N‐chloroalkylamines 3 without using carbonyl compounds in the presence of primary aliphatic amines with the same alkyl fragment, potassium carbonate and a small amount of water in CHCl3 under high pressure (500 MPa), was developed. Diaziridines 1 can be synthesized in the same conditions using a larger amount of potassium carbonate instead of primary aliphatic amines however in lower yields. The kinetic investigations on the synthesis of 1,2‐diethyl‐3‐methyldiaziridine 1a from N‐chloroethylamine 3a have shown that the reaction leading to diaziridine 1a proceeds according to the law of the second order.
Syntheses of oxazolo[4,5‐c]pyridine and 6‐azaindole
Authors: Tjosaas Freddy , Kjerstad Ivar Broendbo , Fiksdahl Anne 
Published: March 2009

Abstractmagnified imageThe preparation of oxazolo[4,5‐c]pyridine and 6‐azaindole from 4‐bromo‐3‐pivaloylaminopyridine (8) is reported. The oxazolopyridine 2‐tert‐butyl‐oxazolo[4,5‐c]pyridine (9) was successfully prepared from 8 in 78% yield by a new base/TBAB promoted non‐catalyzed microwave cyclisation strategy (10 min) or, alternatively, in 54% yield by conventional heating (48 hrs) and CuI catalysis. The 6‐azaindole 2‐phenyl‐1‐(trimethylacetyl)‐6‐azaindole (13) was prepared from 8 in a two step procedure, including a Sonogashira coupling reaction.
Synthesis of 2‐alkyl‐4,5‐aryl‐2H‐[1λ6,2,3,6]‐thiatriazine‐1,1‐dioxides
Authors: Hilp M. 
Published: March 2009

Abstractmagnified imageSulphamoyl chlorides and chlorosulphonyl isocyanate react with monosubstituted hydrazones and alkylhydrazonates to sulphamoyl hydrazones and sulphamoyl hydrazonates respectively. Reaction of benzil monoalkylhydrazones with chlorosulphonyl isocyanate results in formation of 2‐alkyl‐4,5‐aryl‐2H‐ [1λ6,2,3,6]‐thiatriazine‐1,1‐dioxides.
Synthesis of trifluoromethyl‐1,2,4‐triazine‐ and trifluoromethylpyrimidine‐fused uracils
Authors: Takahashi Masahiko , Akiyama Kazuhiko , Suzuki Takumi , Inoue Hiroshi 
Published: March 2009

Abstractmagnified imageA variety of trifluoromethyl‐1,2,4‐triazine‐ and trifluoromethylpyrimidine‐fused uracils (9), (12), (15) and (18) were synthesized from trifluoroacetaldehyde ethyl hemiacetal or trifluoroacetic anhydride and corresponding uracil derivatives.
Microwave‐assisted döbner synthesis of 2‐phenylquinoline‐4‐carboxylic acids and their antiparasitic activities
Authors: Muscia Gisela C. , Carnevale Juan P. , Bollini Mariela , Asís Silvia E. 
Published: March 2009

Abstractmagnified imageA series of twelve substituted 2‐phenylquinoline‐4‐carboxylic acids analogous to antimalarial and antileishmanial natural products was developed via the Döbner reaction employing microwave irradiation (MW). The products were obtained in moderate yields in 0.5‐3 minutes and nine of them were evaluated in vitro against the parasites responsible for malaria, leishmaniasis and trypanosomiasis diseases (WHO, Switzerland). Four compounds exhibited activity against Trypanosoma cruzi and another two resulted active against Plasmodium falciparum and Leishmania infantum, respectively.
Synthesis of new thiazolidine and imidazolidine derivatives of pharmacological interest
Authors: El‐Aasar Nadia K. , Saied Khaled F. 
Published: March 2009

Abstractmagnified imageThe hitherto unknown 5‐(2‐aryl‐2‐oxoethyl)‐4‐oxo‐1,3‐thiazolidines 1a‐l have been synthesized viacycloaddition process between thiourea and/or its derivatives with 3‐aroylpropenoic acids. 1H NMR spectra revealed the presence of 1a‐c as a tautmeric mixture. The presence of the thiazoline tautmers (1a‐c)′ was confirmed by methylating the tautmeric mixture, to the respective methylated derivatives 2‐N‐methylanilino‐5‐(2‐aryl‐2‐oxoethyl)‐4‐oxo‐1,3‐thiazolines2a‐c and 1g‐i. Acidic treatment of 1 provided the respective 2‐oxo homologues 3a‐i. When 1a‐d, k were refluxed with DMF, molecular rearrangement was achieved, providing the 4‐oxo‐2‐thioxoimidazolidine isomers4a‐d, k. Bromination of 4a and 4d in hot acetic acid afforded the respective (E,Z)‐5‐benzoylmethylene derivatives 5a,d which were prepared authentically. Thiation of 1a‐c and 4a‐c gave 5‐aryl‐2,3‐dihydro‐2‐phenyliminothieno[2,3‐d]thiazoles 6a‐cand 1‐phenyl‐5‐aryl‐2,3‐dihydro‐2‐thioxothieno[2,3‐d]imidazoles 7a‐c, respectively. The proposed structures have been confirmed by elemental analysis and spectroscopic data. The selected products showed different antimicrobial effect.
An efficient synthesis of polyhydroacridine derivatives by the three‐component reaction of aldehydes, amines and dimedone in ionic liquid
Authors: Shi Da‐Qing , Ni Sai‐Nan , Fang‐Yang  , Shi Jing‐Wen , Dou Guo‐Lan , Li Xiao‐Yue , Wang Xiang‐Shan 
Published: March 2009

Abstractmagnified imageIn this paper the preparation of 3,3,6,6‐tetramethyl‐9,10‐diaryl‐1,2,3,4,5,6,7,8,9,10‐decahydroacridine‐1,8‐dione derivatives from aldehydes, aromatic amines and 5,5‐dimethyl‐1,3‐cyclohexanedione in 1‐n‐butyl‐3‐methylimidazolium bromide ([bmim]Br) is described. The structures of these compounds were characterized by elemental analysis, IR and1H NMR spectra and further confirmed by single crystal X‐ray diffraction analysis.
One‐pot synthesis of angular furocoumarins: A simple protocol involving unprecedented intramolecular aldol condensation
Authors: Dutta Lakshmi Narayan , De Banani , Patra Amarendra 
Published: March 2009

Abstractmagnified imageRefluxing of hydroxycoumarinyl ketones with methyl γ‐bromocrotonate in dry acetone in presence of anhydrous K2CO3 afforded substituted angelicins (angular furanocoumarins) in satisfactory yields through intramolecular Aldol condensation followed by β‐elimination.
Synthesis and pharmacological investigation of novel 4‐(4‐Ethyl phenyl)‐1‐substituted‐4H‐[1,2,4]triazolo[4,3‐a]‐quinazolin‐5‐ones as new class of H1‐antihistaminic agents
Authors: Alagarsamy V. , Parthiban P. , Solomon V. Raja , Dhanabal K. , Murugesan S. , Saravanan G. , Anjana G. V. 
Published: March 2009

Abstractmagnified imageA series of novel 4‐(4‐ethylphenyl)‐1‐substituted‐4H‐[1,2,4]triazolo[4,3‐a]quinazolin‐5‐ones were synthesized by the cyclization of 2‐hydrazino intermediate with various electrophile. The starting material 2‐hydrazino compound was synthesized from 2‐ethyl aniline by a new innovative route with improved yield. When tested for theirin vivoH1‐antihistaminic activity on conscious guinea pigs, all the test compounds significantly protected the animals from histamine induced bronchospasm. The compoundIIemerged as the most active compound of the series and it is more potent (73.93% protection) when compared to the reference standard, chlorpheniramine maleate (71% protection), it showed negligible sedation (10%) when compared to chlorpheniramine maleate (30%). Therefore compoundIIwill serve as prototype molecule for further development as a new class of H1‐antihistamines
Electrophilic aromatic substitution of 3‐alkoxy‐6‐alkyl‐2‐cyano‐4,5,6a,11‐tetraazabenzo[a]fluorene with orthoesters
Authors: Okamoto Yoshihisa , Yamaguchi Yoshimi , Maeda Mitsuaki , Kurasawa Yoshihisa 
Published: March 2009

Abstractmagnified imageFused tetracycles, 6‐alkyl‐3‐alkoxy‐2‐cyano‐4,5,6a,11‐tetraazabenzo[a]fluorene derivatives (5a,b,c,d,e,f), are synthesized from 2‐alkoxy‐5‐(benzimidazol‐2‐ylidene)‐3‐cyano‐6‐imino‐5,6‐dihydro‐pyridines (4b,c), and when refluxed in ethyl orthoacetate or ethyl orthopropionate, the elecrophilic aromatic substitution occurs at the ortho position of the cyanopyridine ring in the fused tetracycles (5b,c,e,f) to afford 6‐alkyl‐3‐alkoxy‐2‐cyano‐1‐ethyl‐4,5,6a,11‐tetraazabenzo[a]fluorenes(6b,c,e,f).
Gas‐phase thermolysis of benzotriazole derivatives. Part 4. Pyrolysis of 1‐acylbenzotriazole phenylhydrazones. Interesting direct routes towards N‐aminobenzimidazoles
Authors: Al‐Awadi Hanan , Ibrahim Maher R. , Al‐Awadi Nouria A. , Ibrahim Yehia A. 
Published: March 2009

Abstractmagnified imageFlash vacuum pyrolysis (FVP) of 1‐acylbenzotriazole phenylhydrazones gave benzonitriles, aniline and 2‐arylbenzimidazole derivatives. Static pyrolysis of the same substrates at 180 °C gave exclusively the corresponding N‐anilino‐2‐arylbenzimidazole derivatives. Pyrolysis of the isomeric 2‐acylbenzotriazole phenylhydrazones gave similar products.
Barium nitrate catalyzed one pot synthesis of 1,4‐dihydropyridines under solvent free conditions at room temperature
Authors: Sharma Mukul , Agarwal Nisha , Rawat Diwan S. 
Published: March 2009

Abstractmagnified imageBarium nitrate acts as an efficient catalyst for the three‐component one pot synthesis of 1,4‐dihydropyridines. Barium nitrate is a safe chemical, and reaction without the use of organic solvents makes the process eco‐friendly.
Microwave assisted synthesis of novel 6,7,8‐trimethoxy N‐substituted‐4‐aminoquinazoline compounds
Authors: Liu Gang , Sun Lin , Liu Chunping , Ji Chunnuan , Wen Quanwu , Ma Songmei 
Published: March 2009

Abstractmagnified imageA fast, efficient and convenient reaction of 6,7,8‐trimethoxy‐4‐chloroquinazoline and aryl (or benzyl) amines was achieved under microwave irradiation in isopropyl alcohol, providing a simple method for synthesis of novel 6,7,8‐trimethoxy N‐substituted‐4‐aminoquinazoline compounds in good yield in short time. The title compounds were evaluated for their in vitro anti‐proliferative activities against PC3 cell by MTT method.
Fused pyridines by a tandem aza‐wittig / heterocyclization strategy: Synthesis of 1,2,4‐triazolo[1,5‐a]pyridines and pyrido[1,2‐b][1,2,4]triazines
Authors: Barsy Magda A. , El Rady Eman A. , El Latif Fawi M. Abd 
Published: March 2009

Abstractmagnified imageThe iminophosphorane 1‐amino‐6‐(triphenylphosphoranylideneamino)‐2‐oxo‐4‐phenyl‐1,2‐dihydro‐pyridine‐3,5‐dicarbonitrile 2 prepared from 1,6‐diaminopyridine 1 reacts with heterocumulenes such as carbon disulfide and phenylisocyanate, and with acid chlorides, acid anhydrides and haloketones to give directly the title compounds in an one‐pot aza‐Wittig / heterocyclic‐ring closure process with good yields.
Synthesis of 3‐(2‐hydroxy‐1‐phenylethyl)‐ and 3‐(2‐hydroxy‐2‐phenylethyl)adenine, DNA adducts derived from styrene
Authors: Krouželka Jan , Linhart Igor , Tobrman Tomáš 
Published: March 2009

Abstractmagnified image3‐(2‐Hydroxy‐2‐phenylethyl)‐ and 3‐(2‐hydroxy‐1‐phenylethyl)adenine, DNA adducts derived from styrene, along with their 9‐substituted analogues were prepared by alkylation of 8‐bromoadenine with corresponding allyl‐protected bromohydrins followed by a new deallylation procedure using tetrakis(triphenylphosphine)palladium catalyzed reductive cleavage by poly(methylhydrosiloxane) in the presence of p‐toluenesulphonic acid. This novel procedure proved to be useful for purine derivatives, which were resistant to other deallylation protocols. Structure of positional isomers was assigned using 2D NMR experiments HMBC and HMQC.
Thermal reactions of N‐alkyl‐2‐benzylaniline and N‐alkyl‐N′‐phenyl‐o‐phenylenediamine: An unusual route to 2‐phenylindole and 2‐phenylbenzimidazole
Authors: Creencia Evelyn Cuevas , Taguchi Kei , Horaguchi Takaaki 
Published: March 2009

Abstractmagnified imageThermal cyclization reactions of N‐alkyl‐2‐benzylaniline 1a‐d and N‐alkyl‐N′‐phenyl‐o‐phenylenediamine 2a‐b were carried out expecting to get seven‐membered heterocyclic compounds. However, the results show that aside from the formation of the normally expected six‐membered ring products of acridine 5, anthracene 6, and phenazine 8, thermal cyclization of N‐alkyl‐2‐benzylaniline and N‐alkyl‐N′‐phenyl‐o‐phenylenediamine also resulted to the unexpected formation of 2‐phenylindole 3 and 2,3‐diphenylindole 4, and 2‐phenylbenzimidazole 7, respectively.
The cycloacylation — 1,3‐Acylrearrangement sequence as tool for highly substituted pyrrolones
Authors: Buehrdel Gunther , Beckert Rainer , Friedrich Birgit , Goerls Helmar 
Published: March 2009

Abstractmagnified imageThe cyclization reactions between bis‐imidoylchlorides 1 and ketones, which possess different CH‐acidity, were investigated. Diphenylacetone 2 reacts under mild conditions via C,O‐cyclization of the preformed enolate to yield the iminofurane derivative 3. Upon treatment with trifluoroacetic acid, the latter can be rearranged quantitatively into the pyrrolone 5. In contrast, 1,3‐acetonedicarboxylate 9 and cyclohexanone 12 immediately lead to highly substituted pyrrolones 11 and 14. Obviously, the primarily formed cyclization products undergo a very fast 1,3‐acyl rearrangement (Dimroth‐/Mumm‐Rearrangement). The structures of the maleiimide 11 and the indolone 14 were determined by single crystal X‐ray structure analysis. Due to its amino/imino substructure, compound 3 is an efficient ligand for metal complexation reactions, exemplified by the synthesis of two different Zn‐complexes 7 and 8.
Salicylaldehyde based oxazolidines as catalysts for the asymmetric addition of diethylzinc to aldehydes
Authors: Parrott Raleigh W. , Hamaker Christopher G. , Hitchcock Shawn R. 
Published: March 2009

Abstractmagnified imageA series of oxazolidines have been prepared by condensation of N‐isopropyl norephedrine with a variety of salicylaldehyde derivatives. Despite the stereochemical relationship of (1R,2S)‐norephedrine with (1R,2S)‐ephedrine, the resultant oxazolidines 12‐14 were determined to have a stronger stereochemical relationship with (1S,2S)‐pseudoephedrine based oxazolidines. The resultant oxazolidines were used as catalytic ligands in the addition of diethylzinc to several aldehydes. It was determined that the oxazolidine derivative 12 gave the highest yield and a moderate enantioselectivity.
New synthetic route towards 2,2‐dimethylchromene and synthesis of substituted 7‐(dimethylpropargyl)chromene
Authors: Alizadeh Babak H. , Foroumadi Alireza , Shafiee Abass 
Published: March 2009

Abstractmagnified imageTrifluoromethansufonic acid (TFA) was found a proper reagent for regioselectively ring closure of resorcinol to afford 7‐hydroxy‐2,2‐dimethyl‐2,3‐dihydrochromen‐4‐one 3. The propargylation of 3 gave rise to 2,2‐dimethyl‐7‐(2‐methylbut‐3‐yn‐2‐yloxy)‐2,3‐dihydrochromen‐4‐one 4. Condensation of 4 with substituted phenyl or benzyl Grignard reagents afforded substituted phenyl or benzylidene chromenes 6a‐d and 4‐(substitutedbenzylidene)‐3,4‐dihydro chromenes 8a‐e, respectively.
An efficient preparation of new homoallylamines and α‐aminonitriles bearing furyl and thienyl rings
Authors: Méndez Leonor Y. Vargas , Kouznetsov Vladimir V. 
Published: March 2009

Abstractmagnified imageNew diverse N‐aryl‐N‐[1‐furyl(thienyl)but‐3‐enyl]amines (homoallylamines) or 2‐(N‐arylmethylamino)‐2‐furyl(thienyl)acetonitriles (α‐aminonitriles) were easily prepared in good to excellent yields by an indium‐mediated Barbier‐type reaction between N‐hetarylaldimines and allyl bromide in MeOH or a direct three component reaction between anilines, hetaryl aldehydes and trimethylsilyl cyanide in the presence of a catalytic amount of molecular iodine at room temperature, respectively. The entire set of amines was characterized by IR, 1H and 13C NMR spectroscopy.
A simple procedure for the synthesis of benzoxanthene derivatives under microwave irradiation conditions
Authors: Chen Yan , Wu Shanshan , Tu Shujiang , Li Chunmei , Shi Feng 
Published: March 2009

Abstractmagnified imageA rapid and efficient method is developed to synthesize a series of benzoxanthene derivatives by the reaction of aldehydes and 2‐hydroxynaphthalene‐1,4‐dione in mixed solvent of acetic acid and ethylene glycol under microwave irradiation. The method has the advantages of short synthetic route, operational simplicity and higher yields (70%∼85%).
Dodecyloxy‐substituted 2,4,6‐tris(styryl)pyridines
Authors: Lifka Thorsten , Oehlhof Annette , Meier Herbert 
Published: March 2009

Abstractmagnified image(E,E,E)‐2,4,6‐Tris(styryl)pyridines 2a‐c with 3, 6 or 9 dodecyloxy substituents were prepared by the highly stereoselective condensation reaction of collidine (8) and the corresponding phenyl‐(1‐phenyl‐methylidene)amines 7a‐c (Siegrist reaction). In contrast to the corresponding compounds with a benzene or a 1,3,5‐triazine core, 2a‐c do not show any hints for the formation of thermotropic liquid crystals. The major application of such star‐shaped systems is in the field of nonlinear optics.
Progress in the chemistry of 4‐ thiazolidinones
Authors: Hamama Wafaa S. , Ismail Mohamed A. , Shaaban Saad , Zoorob Hanafi H. 
Published: March 2009

Abstractmagnified imageThis review article includes a recent development in the chemistry of 4‐thiazolidinones. Structure, basicity, synthetic aspects, reactions, and applications were also reported.
Regio‐ and stereoselective synthesis of isoxazolidine derivatives by asymmetric 1,3‐dipolar cycloaddition reaction of chiral nitrones with 1‐propene‐1,3‐sultone
Authors: Zhang Hong‐Kui , Chan Wing‐Hong , Leeb Albert W. M. , Wong Wai‐Yeung 
Published: March 2009

Abstractmagnified imageAsymmetric 1,3‐dipolar cycloadditions of chiral nitrones to 1‐propene‐1,3‐sultone (1) were investigated. Chiral nitrones 6a‐e reacted with sultone 1 in toluene at 90 °C for 24‐36 h to give the corresponding isoxazolidines in moderate yields with high regioselectivities and stereoselectivities. The diastereoselectivity of this reaction varied with the choice of dipolarophile and the steric demands of nitrones. When sultone 1 was allowed to react chiral nitrone 6e, a much better diastereoselectivity of up to 5.1:1 was observed.
Photocyclisations of some 3‐alkoxy‐2‐thienylchromones
Authors: Yusuf Mohamad , Kumar Rupesh , Gupta S. C. 
Published: March 2009

Abstractmagnified imagePhotoreorganisations of some 3‐allyloxy‐2‐thienylchromones have been described. The photoreactions are initiated through the intramolecular H‐abstraction to provide angular tetracyclic compounds. These chromones yield good chemical efficiency due to the involvement of highly stabilized allylic 1,4‐biradicals.
N‐[(Diphenoxyphosphoryl)oxy]‐2‐phenyl‐1H‐benzimidazole as a versatile reagent for synthesis O‐alkylhydroxamic acids
Authors: Kokare Nagnnath D. , Shinde Devanand B. 
Published: March 2009

Abstractmagnified imageHighly efficient reagent, N‐[(diphenoxyphosphoryl)oxy]‐2‐phenyl‐1H‐benzimidazole was synthesized and its applicability was demonstrated for the synthesis of O‐alkyl hydroxamic acids. The efficiency of the reagent was evaluated through the synthesis of range of O‐alkyl hydroxamic acids from aromatic carboxylic acids as well as N‐protected amino acids. The enatiomeric purity of synthesized compounds was measured using chiral HPLC and the degree of racemization that occurred was found to be negligible.