bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidences of some unusual behaviours of 2‐aminothiazol and 2‐aminobenzothiazol in reactions with formaldehyde and glyoxal
Authors: Ghandi Mehdi , Olyaei Abolfazl 
Published: March 2009

Abstractmagnified imageIn contrast to the previously reported acid‐catalyzed reaction of 2‐aminothiazole with aqueous formaldehyde in water at 0‐5 °C which afforded N,N′‐bis(2‐thiazolyl)methanediamine (4), 5,5′‐methylenebis(2‐aminothiazole) (5) is obtained as the unique product under reflux conditions. Reaction of 2‐aminobenzothiazole with aqueous formaldehyde in acetonitrile at 0‐5 °C or under reflux conditions produces (2‐benzothiazolylamino)methanol (6) or N,N′‐bis(2‐benzothiazolyl)methanediamine (7), respectively. Heating monoamine 6 in acetonitrile remarkably yields the symmetric diamine 7. While cyclocondensation of 2‐aminothiazole with aqueous glyoxal in acetonitrile gives 3,4,8,9‐tetrahydroxy‐7,10‐bis(2‐thiazolyl)‐2,5‐dioxa‐7,10‐diazabicyclo[4.4.0]decane (8), reaction of 2‐aminobenzothiazole with glyoxal fails to produce similar results; In the presence of aqueous formaldehyde, although the former reaction leads to the formation of 4‐hydroxy‐5‐(thiazolylamino)‐1,3‐bis(2‐thiazolyl)imidazolidine (9), utilization of 2‐aminobenzothiazole gives 4,5‐dihydroxy‐1,3‐bis(2‐benzothiazolyl)imidazolidine (10). Condensation of either 6 or 7 with aqueous glyoxal affords compound 10. Details of the reactions will be discussed in this presentation.
Synthesis of pyrazolo‐annelated heterocyclic ring compounds such as pyrazolo[3,4‐b]pyridines and pyrazolo[4′,3′:5,6]‐pyrido[2,3‐d]pyrimidines
Authors: Jachak Madhukar N. , Avhale Appasaheb B. , Toche Ragunath B. , Sabnis Ram W. 
Published: March 2009

Abstractmagnified imageA series of pyrazolo[3,4‐b]pyridines has been synthesized by Friedländer condensation of 5‐amino‐pyrazole‐4‐carbaldehyde 1 with active methylene compounds in basic medium. Pyrazolo[4′3′:5,6]pyrido‐[2,3‐d]pyrimidines have been synthesized from pyrazolo[3,4‐b]pyridines using substituted urea and acetic anhydride.
Synthesis of 2,2′‐bipyridyl‐type compounds via the suzuki‐miyaura cross‐coupling reaction
Authors: Jones Nicholas A. , Antoon James W. , Bowie Alfred L. , Borak J. Brian , Stevens Erland P. 
Published: March 2009

Abstractmagnified image2,2′‐Bipyridyl‐type compounds may be prepared by Suzuki‐Miyaura coupling of a 2‐pyridylboronic ester with 2‐haloazines and ‐azoles. Ten examples are presented with yields of 47 to 84%. Both arylbromides and arylchlorides undergo the coupling, but the reaction is sensitive to ring substitution adjacent to the halogen.
Synthesis and antimicrobial activity of some new N‐(substituted phenyl)‐N′‐[2,3‐dihydro‐2‐oxido‐3‐(4′‐fluorophenyl)‐1H‐(1,3,2)benzoxazaphosphorin 2‐yl]ureas
Authors: Haranath P. , Kumar V. Sreedhar , Reddy C. Suresh , Raju C. Naga , Reddy C. Devendranath 
Published: March 2009

Abstractmagnified imageSubstituted benzoxazaphosphorin 2‐yl ureas were synthesized by reacting 2‐(4‐fluoro‐phenylamino)‐methylphenol (4) with different carbamidophosphoric acid dichlorides (3) in the presence of triethylamine in dry toluene at 45‐50 °C and characterized by spectral data. These compounds were found to possess good antimicrobial activity.
Nitropyridyl isocyanates in 1,3‐dipolar cycloaddition reactions
Authors: Holt Jarle , Fiksdahl Anne 
Published: March 2009

Abstractmagnified imageThe reactivity of 3‐nitro‐4‐pyridyl isocyanate (7) and 5‐nitropyridin‐2‐yl isocyanate (9) in 1,3‐dipolar cycloaddition reactions with azides and pyridine N‐oxides has been investigated. 1,3‐Dipolar cycloaddition to trimethylsilylazide (TMSA) afforded the respective tetrazolinones, 1‐(3‐nitropyridin‐4‐yl)‐1H‐tetrazol‐5(4H)one (8, 50 %) and 1‐(5‐nitropyridin‐2‐yl)‐1H‐tetrazol‐5(4H)one (11, 64 %). Respectively, 1,3‐dipolar cycloaddition of nitropyridyl isocyanates 7 and 9 to 3,5‐dimethylpyridine N‐oxide (14), 3‐methylpyridine N‐oxide (21) and pyridine N‐oxide (22) gave the substituted amines, 3,5‐dimethyl‐N‐(3‐nitropyridin‐4‐yl)pyridin‐2‐amine (17), 3,5‐dimethyl‐N‐(5‐nitropyridin‐2‐yl)pyridin‐2‐amine (20), N‐(5‐nitropyridin‐2‐yl)pyridin‐2‐amine (24), 5‐methyl‐N‐(5‐nitropyridin‐2‐yl)pyridin‐2‐amine (23) and 3‐methyl‐N‐(5‐nitropyridin‐2‐yl)pyridin‐2‐amine (25) in 65 ‐ 80 % yield, obtained by cycloaddition, rearrangement and decarboxylation. The results demonstrate that the nitropyridyl isocyanates (7,9) readily undergo 1,3‐dipolar cyloaddition reactions similar to phenyl isocyanates.
Synthesis of thiazolines by the reaction of aryl ketonitriles with cysteamine via microwave irradiation
Authors: Kamila Sukanta , Biehl Edward R. 
Published: March 2009

Abstractmagnified imageThiazolines were synthesized in a one‐pot reaction in excellent yield using a newly developed methodology. Ketonitriles were directly condensed with cysteamine (2‐amino‐thioalcohol) via microwave irradiation at 210°C for 10 minutes under solvent free conditions and without any solid support. All the compounds were characterized by 1H nmr, 13C nmr spectroscopy and elemental analyses.
A novel synthesis of indole derivatives by the reaction of N‐arylhydroxamic acids with malononitrile
Authors: Tomioka Yukihiko , Ohkubo Kimiko , Maruoka Hiroshi 
Published: March 2009

Abstractmagnified imageAn approach to indole derivatives from N‐arylhydroxamic acids and malononitrile via a [3,3]‐sigmatropic rearrangement and intramolecular cyclization is described. Reactions of N‐arylhydroxamic acids 1a‐c, 2a‐c and 3a‐c with malononitrile in the presence of triethylamine at room temperature gave the corresponding α‐cyanoacetamide derivatives 4a‐c, 5a‐c, 6a‐c, 7a‐c and 8a‐c. Thermal treatment of 4a‐c, 5a‐c and 7a‐c with a base, e.g. triethylamine and sodium methoxide, caused intramolecular cyclization and deacylation to afford the corresponding indole derivatives 9‐11.
Reaction of 3‐formylchromone‐N‐benzoylhydrazone with ketenes. Synthesis and structural studies of chromone 1,3,4‐oxadiazolines
Authors: Kaspentakis George C. , Tsoleridis Constantinos A. , Stephanidou‐Stephanatou Julia 
Published: March 2009

Abstractmagnified imageThe reaction of 3‐formylchromone‐N‐benzoylhydrazone with ketenes, prepared in situ from the corresponding acid chlorides 2a‐d and the mixed anhydride 2e was studied. In all cases 2‐(4′‐oxo‐4′H‐3′‐chromyl)‐5‐phenyl‐2,3‐dihydro‐1,3,4‐oxadiazoles (3) were isolated in yields varying from 40 to 80%. A full structure assignment of all products has been made on the basis of 1D and 2‐D (COSY H‐H, COSY C‐H, COLOC C‐H) NMR spectra. A plausible reaction mechanism is also proposed based on theoretical approaches and experimental results.
Cycloaddition reactions with 2,3‐benzodiazepine derivatives
Authors: Kertész Máriusz , Pallagi István , Sólyom Sándor 
Published: March 2009

Abstractmagnified imageWe report here on some 3+2 dipolar cycloaddition reactions of propargyl, allyl and cyano substituted 2,3‐benzodiazepines within situgenerated nitrile oxides and diazomethane. The reactivity of carbon‐nitrogen double bonds of the 5H‐[2,3]benzodiazepine ring system was also noticed.
Biginelli‐like three component reaction: Synthesis of some new ethyl 6‐ethoxycarbonylmethyl‐4‐aryl‐2‐oxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carboxylate derivatives
Authors: Azizian Javad , Mohammadi Ali A. , Kohshari M. , Karimi Ali R. , Mohammadizadeh Mohammad R. 
Published: March 2009

Abstractmagnified imageIn the context of our high‐throughput organic synthesis program, we have studied the reactivity of special β‐keto esters toward the Biginelli reaction. We have found that a diethyl‐3‐oxoglutarate reacts with one molecule of urea and one molecule of aldehyde under solvent‐free conditions to give a new family of 3,4‐dihydropyrimidin‐2(1H)‐ones in good yields.
Synthesis of a new class of sulfone linked bisheterocycles
Authors: Padmavathi Venkatapuram , Reddy Boreddy Chandra Obula , Mohan Annaji Venkata Nagendra , Padmaja Adivireddy 
Published: March 2009

Abstractmagnified imageSome bisheterocycles having pyrrole and oxazoline/thiazoline units were synthesized from Z‐styrylsulfonylacetic acid methyl esters using samarium chloride.
1,3‐Dibromo‐5,5‐dimethylhydantoin (DBH) as an efficient promoter for acetylation of 3‐arylsydnones in the presence of acetic anhydride under neutral conditions
Authors: Azarifar Davood , Bosra Hassan Ghasemnejad , Tajbaksh Mahmood 
Published: March 2009

Abstractmagnified image1,3‐Dibromo‐5,5‐dimethylhydantoin (DBH) has been found to efficiently promote the conversion of various 3‐arylsydnones to their 4‐acetyl congeners in the presence of acetic anhydride under neutral conditions in satisfactory yields.
Synthesis of 5,6,7,8‐tetrahydroindolizines via a domino‐type transformation based on the rhodium catalyzed hydroformylation of N‐(β‐methallyl)pyrroles
Authors: Rocchiccioli Silvia , Guazzelli Giuditta , Lazzaroni Raffaello , Settambolo Roberta 
Published: March 2009

Abstractmagnified imageVariously substituted 5,6,7,8‐tetrahydroindolizines can be easily synthesized via a domino reactions sequence under rhodium catalyzed hydroformylation of N‐(β‐methallyl)pyrroles. The later are readily prepared from properly functionalized pyrroles via phase‐transfer N‐allylation in the presence of 18‐crown‐6 and potassium tert‐butoxide.
Deoxygenation of pyridine N‐oxides with dimethylthiocarbamoyl chloride
Authors: Ponaras Anthony A. , Zaim Ömer 
Published: March 2009

Abstractmagnified imageTreatment of pyridine N‐oxides with dimethylthiocarbamoyl chloride in boiling acetonitrile effects chemoselective deoxygenation to pyridines.
A new synthesis of alkaloid (S)‐3‐hydroxypiperidin‐2‐one and its O‐TBS protected derivative
Authors: Huang Pei‐Qiang , Chen Guo , Zheng Xiao 
Published: March 2009

Abstractmagnified imageFrom the known lactone (S)‐4, easily derived from L‐glutamic acid, a scalable approach to chiral building block O‐silylated 3‐hydroxypiperidin‐2‐one 3 and alkaloid 1 was achieved in five and six‐steps respectively. The key steps are a chemoselective amidation of lactone‐ester 5 and a one‐pot reductive borane‐decomplexation, N‐debenzylation and cyclization.
Alkylation of azoles: Synthesis of new heterocyclic‐based AT1‐non‐peptide angiotensin (II) receptor antagonists
Authors: Al‐Azmi Amal , George Paulson , El‐Dusouqui Osman M. E. 
Published: March 2009

Abstractmagnified imageSeveral novel analogues of Losartan2were synthesized as potential non‐peptide angiotensin (II) receptor antagonists. In these non‐peptide analogues, the tetrazole and the substituted imidazole rings of Losartan2were replaced, respectively, by a carboxylic acid function or its methyl ester and substituted triazole, imidazole or benzimidazole moieties. The biphenyl bromide precursor3(BPE) used to introduce the linker between the acid/ester function and the heterocyclic moiety was synthesized using Suzuki biphenyl coupling and then incorporated into the target molecule by simple nucleophilic substitution. The fixed N‐aryl isomeric forms of several azole and benzimidazole tautomers were successfully separated by HPLC using 50% aqueous acetonitrile as eluent. Intermediate reaction products and final target compounds were fully characterized spectroscopically.
Synthesis of some novel fused oxo‐ and thiopyrimidines via an intramolecular friedel‐crafts reaction
Authors: Mobinikhaledi Akbar , Foroughifar Naser , Javidan Abdollah , Amini Ehsan 
Published: March 2009

Abstractmagnified image1H‐Indeno[1,2‐d]pyrimidine‐2,5(3H,9bH)‐dione derivatives 2(a‐i) and 2,3‐dihydro‐2‐thioxo‐1H‐indeno[1,2‐d]pyrimidine‐5(9bH)‐ones 2(j‐q) were synthesized via an intramolecular Friedel‐Crafts reaction between the aryl and ester group of ethyl 6‐methyl‐4‐aryl‐2‐oxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carboxylates 1a‐i, and their thioxo analogs using AlCl3 and acetyl chloride in nitrobenzene. Yields of the products, after washing with THF, were of the order of 45‐69%. IR and NMR spectroscopy together with elemental analysis were used for identification of these compounds.
Asymmetric alkylation of N‐acylisoindolin‐1‐ones via α‐bromoimides: A novel route to 1‐substituted isoindolines
Authors: Müller Andreas , Polborn Kurt , Wanner Klaus T. 
Published: March 2009

Abstractmagnified imageKey intermediate in the synthesis of the title compounds 9a‐c and 10a‐c was the chiral α‐bromoimide 1 which has been prepared by radical bromination of the corresponding N‐acylisoindolin‐1‐one 13. 1 was alkylated with silyl enol ethers under Lewis acid catalysis using α‐amidoalkylation methodology. N,N‐diacyliminium ion 14 is presumably the intermediate in this reaction. Further transformations of the alkylated compounds yielded 1‐substituted isoindolines as target compounds.
Metallation reactions. XXXVI. A study on the metallation of (methylthio)‐ and (methylsulfonyl)thiophenes
Authors: Fattuoni Claudia , Usai Michele , Cabiddu Maria G. , Cadoni Enzo , De Montis Stefania , Sotgiu Francesca , Cabiddu Salvatore 
Published: March 2009

Abstractmagnified imageMethylthio‐ and methylsulfonyl thiophenes were polymetallated by n‐buthyllithium and superbase (LICKOR) in one‐step. 2‐(Methylthio)thiophene was bimetallated in 5 and in alpha to the methylthio sulfur atom by superbase. 3‐(Methylthio)thiophene was bimetallated in both 2 and 5 positions by the organolithium and trimetallated in these two positions and in alpha to the thioethereal sulfur atom by superbase. 3‐(Methylsulfonyl)thiophene was bimetallated in 2 and in alpha to the sulfonyl sulfur atom by the organolithium while the 2‐(methylsulfonyl)thiophene underwent degradation in the same conditions.
Reaction of phthalaldehydic acid with different substituted aniline as well as hydrazine derivatives
Authors: Khattab Sherine N. , Hassan Seham Y. , El‐Faham Ayman , El Massry Abdel Moneim M. , Amer Adel 
Published: March 2009

Abstractmagnified imagePhthalaldehydic acid 1 is often represented as having two tautomeric forms 1a and 1b. The reaction of phthalaldehydic acid with different aryl amine and heterocyclic aryl hydrazine derivatives afforded different products depending on the reaction conditions such as solvent and temperature.
Synthesis of substituted 1,2,4‐oxadiazoles from substituted acid chlorides and amidoximes under mild conditions
Authors: Bora Rajesh O. , Farooqui Mazahar 
Published: March 2009

Abstractmagnified imageSubstituted amidoximes have been synthesized, isolated and converted into substituted oxadiazoles as a novel heterocyclic compounds under mild conditions in good to excellent yield.
Synthesis of mixed‐donor azaoxathia macrocyclic tetraamides, acyclic polyether di/and tetraamides and their C‐pivot lariat derivatives
Authors: Abbas Ashraf A. 
Published: March 2009

Abstractmagnified imageThe macrocyclic tetraamides11a‐eand 15‐hydroxy macrocyclic tetraamides23a‐cwere prepared in good yields by the nucleophilic reaction of the potassium salts of the bis‐phenoles10a‐cwith the appropriate dihalo compounds5a‐dand15.Moreover, the acyclic diamides7, 9, 17‐21and bis‐acyclic tetraamide22were obtained in high yields by the reaction of the appropriate dichloro compounds with different phenoxides and secondary amines. Acylation of23a‐cwith different acid chlorides gave the corresponding esters24a‐c.Compounds24a‐creacted with different secondary amines to afford the corresponding novel lariat macrocycles25a‐din high yields.
Hetarenium salts from pentafluoropyridine. Syntheses, spectroscopic properties, and applications
Authors: Schmidt Andreas , Mordhorst Thorsten , Namyslo Jan Christoph , Telle Werner 
Published: March 2009

Abstractmagnified imageReaction of pentafluoropyridine with nucleophilic heteroaromatics such as 4‐(dimethylamino)pyridine, 4‐(pyrrolidin‐1‐yl)pyridine, 4‐(morpholin‐4‐yl)pyridine, 4‐aminopyridine, and 3,4‐diaminopyridine resulted in the formation of 4‐hetarenium substituted tetrafluoropyridines. The 4‐(dimethylamino)‐pyridinium derivative underwent substitution reactions with isopropanolate, isopropanethiolate, and benzylthiolate to F2,F3,O4,F5,F6‐ and O2,F3,O4,F5,F6‐pentasubstituted pyridines as well as their sulfur analogs. N‐Propylamine, isopropylamine, and piperidine formed 4‐amino‐N2,F3,F5,F6‐pentasubstituted pyridines in the presence of sodium amide as base, whereas morpholine gave the 4‐amino‐2,6‐bis‐morpholino‐substituted 3,5‐difluoropyridine. 19F, 15N, 13C, and 1H nmr spectrocopy was performed to elucidate the structures of the substitution products.
Synthesis of some 2‐oxo and 2‐thioxo substituted pyrimidines using solvent‐free conditions
Authors: Mobinikhaledi Akbar , Forughifar Naser , Alipour Safari Jil A. , Amini EhsaN. 
Published: March 2009

Abstractmagnified imageA series of oxo‐ and thioxopyrimidines 4(a‐m) were synthesized by one‐pot three components cyclocondensation reaction of β‐ketoester, aldehyde and urea/thiourea using benzyltriethylammonium chloride as a catalyst under solvent‐free conditions. The yields of products following recrystallization from ethanol were of the order of 65‐87%. IR and 1HNMR spectroscopy and elemental analysis were used for identification of these compounds.
Synthesis and reactivity of 1‐amino‐4‐methyl‐3,4‐dihydro‐5H‐pyrazolo[3′,4′:4,5]pyrimido[1,6‐a]benzoimidazolo‐5‐one
Authors: Abdelhamid Abdou O. , Awad Ahmed A. 
Published: March 2009

Abstractmagnified imagePyrimido[2“,1”:5′,6′]pyrazolo[3′,4′:4,5]‐pyrimido[1,6‐a]benzoimidazoloe‐2,8(1H,7H)‐diones, and [1,2,4]‐triazino‐[3“,4”:5′,6′]pyrazolo[3′,4′:4,5]pyrimido[1,6‐a]benzimidazol‐8(7H)‐ones were synthesized in a good yields via 1‐amino‐4‐methyl‐3,4‐dihydro‐5H‐pyrazolo[3′,4′:4,5]pyrimido[1,6‐a]benzoimidazolo‐5‐one and the appropriate active methylene compounds. Structures of the newly synthesized compounds were elucidated on the basis of elemental analyses, spectral data, and alternative synthesis methods whenever possible.
Studies with 2‐arylhydrazononitriles: A novel simple, efficient route to 5‐acyl‐2‐substituted‐1,2,3‐triazol‐4‐amines
Authors: Aziz Suzan Ibrahim , Anwar Hany Fakhry , Elnagdi Mohamed Hilmy , Fleita Daisy Hanna 
Published: March 2009

Abstractmagnified imageEfficient route to 5‐acyl‐2‐substituted‐1,2,3‐triazol‐4‐amines via reaction of 3‐oxo‐2‐(arylhydrazono)‐pentanenitrile with hydroxylamine hydrochloride is reported. X‐ray crystal structure has been made to confirm the structure of reaction products.
Synthesis and antimicrobial activity of some novel furyl and benzimidazole substituted benzyl ethers
Authors: Güven Özden Özel , Erdoǧan Taner , Göker Hakan , Y1ld1z Sulhiye 
Published: March 2009

Abstractmagnified imageIn this study, a series of novel furyl and benzimidazole substituted benzyl ethers were synthesized and evaluated for antibacterial and antifungal activities against S. aureus, Methicillin resistant S. aureus (MRSA), E. coli, C. albicans and C. krusei. Compound 6f and 6h exhibited the most potent anti‐bacterial activity with lowest MIC values of 3.12 μg/mL against S aureus and MRSA, respectively.
Synthesis of alkyl 6‐methyl‐4‐(2‐pyridyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylates for evaluation as calcium channel antagonists
Authors: Kaur Kuljeet , Knaus Edward E. 
Published: March 2009

Abstractmagnified imageThe Bigenelli acid catalyzed condensation of 2‐pyridylcarboxaldehyde (1), urea (2) and an alkyl acetoacetate (3) afforded the respective alkyl (Me, Et, i‐Pr, i‐Bu, t‐Bu) 6‐methyl‐4‐(2‐pyridyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylates (4a‐e). The most potent calcium channel antagonist ethyl 6‐methyl‐4‐(2‐pyridyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylate (4b, IC50 = 1.67 × 10−5 M) wasa much weaker calcium channel antagonist than the reference drug nifedipine (Adalat®, IC50 = 1.40 × 10−8 M) on guinea pig ileal longitudinal smooth muscle (GPILSM). The alkyl 6‐methyl‐4‐(2‐pyridyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylates did not show any inotropic effect on heart since no increase, or decrease, in the contractile force of guinea pig left atrium was observed. These structure activity studies show that the alkyl 6‐methyl‐4‐(2‐pyridyl)‐1,2,3,4‐tetrahydro‐2H‐pyrimidine‐2‐one‐5‐carboxylates (4a‐e) are partial bioisosteres of nifedipine with respect to calcium channel antagonist activity on guinea pig ileal longitudinal smooth muscle (GPILSM).
Synthesis and herbicidal activities of a series of di(aminopyrazoly) ketone derivatives
Authors: Li Jun‐Fei , Zhu You‐Quan , Wang Xin , Yang Hua‐Zheng 
Published: March 2009

Abstractmagnified imageIn order to obtain new lead compounds with high herbicidal activity, a series of 5‐amino pyrazole derivatives were designed and synthesized using a series of relational synthons. Their structures were determined by IR, 1H NMR, and elemental analyses. These compounds were screened for herbicidal activities against rape and barnyard grass. Their structure‐activity relationships are discussed.
A post‐SCF quantum chemistry study on local minima of 8‐oxo‐guanine stacked with all four nucleic acid bases in B‐DNA conformations
Authors: Cysewski Piotr , Czyżnikowska‐Balcerak Żaneta 
Published: March 2009

Abstractmagnified imageThe post SCF MP2/6‐31G*(d=0.25) method was applied to obtain potential energy surface of 8‐oxoguanine stacked with all four canonical DNA bases. The spatial neighbourhood was scanned of stacked complexes found in the native B‐DNA. The presented results suggest that the hydroxyl radical modification of guanine at C8 position has significant impact on structural, energetic, orbital and electrostatic properties of stacked complexes with canonical DNA bases. The pair stabilization energy, including electron correlation terms, suggests that the 5′‐A/GA‐3′ pair is the most stable among all of the studied complexes. The 8‐oxo‐guanine has been found as a source of significant changes in electroaccepting properties compared to stacked pairs formed by canonical guanine since both electron affinities and localization of HOMO orbital were altered. However, electro‐donation abilities are not modified after replacement of guanine with 8‐oxo‐guanine irrespectively on the context of B‐DNA bases.
New fluorescent bis‐β‐cyclodextrin‐indolizine sensor. Synthesis and sensing ability
Authors: Surpateanu Georgiana G. , Landy David , Lungu Neculai C. , Fourmentin Sophie , Surpateanu Gheorghe 
Published: March 2009

Abstractmagnified imageThe synthesis of 1,3‐[bis‐N‐6A‐deoxy‐β‐cyclodextrin‐6A‐yl‐aminocabonyl]‐7‐pyridin‐4‐yl indolizine is reported. The reaction proceeds by an amidation between 6‐amino‐β‐cyclodextrin and 1,3‐[bis‐(‐4‐nitrophenoxycarbonyl)‐7‐[pyridine‐4‐yl)] and yields the first sensor having in its structure the fluorescent indolizine and two β‐cyclodextrin fragments. The sensing ability towards phenol, p‐cresol and adamantan‐1‐ol has been evaluated by fluorescence spectroscopy. The molecular modelling study realised by MM3 and AM1 methods shows that non cooperative conformations are favoured, thus explaining that inclusion ability is not increased by such dimer, and that sensitivity is not enhanced as compared to corresponding monomeric sensors.
Towards the syntheses of N‐H and N‐alkylated derivatives of meridianins
Authors: Corbel Bernard , Michaud FrançOis , Meijer Laurent , Simon Gaëlle , Couthon‐Gourves Hélène , Haelters Jean‐Pierre , Kervarec Nelly 
Published: March 2009

Abstractmagnified imageNovel N‐H and N‐alkylated derivatives of meridianins have been synthesized as potential antitumor agents by a two‐step conversion of N‐tosyl‐3‐acetylindoles or N‐alkyl‐3‐acetylindoles to the corresponding enaminones using DMF‐DMA, with or without added pyrrolidine. Further cyclization with guanidine gave the corresponding 2‐aminopyrimidines. The structures of the compounds, thus obtained, were proved by 1H and 13C NMR spectroscopy, NOE experiments and X‐ray analysis.