bluuebunny/crossref_metadata_2025_split huggingface dataset:
Denitrocyclization in synthesis of dibenzo[b,f][1,4]thiazepin‐11(10h)‐ones and their derivatives
Authors: Smirnov Alexey V. , Kalandadze Levan S. , Sakharov Vladimir N. , Dorogov Mikhail V. , Ivachtchenko Alexander V. 
Published: March 2009

Abstractmagnified imageA convenient synthesis of the novel dibenzo[b,f][1,4]thiazepin‐11(10H)‐ones is reported. As a key step, the synthetic route includes intramolecular aromatic denitrocyclization of 2‐(2,4‐dinitro‐phenylsulfanyl)‐benzoic acid amides. Efficient procedures for denitrocyclization in the presence of different bases are developed. Reduction of the nitro group in the obtained heterocycles resulted in formation of primary amines, which were transformed into amides by acylation with different carboxylic acids. The synthesized compounds have a great potential of bioactivity and are useful objects for biomedicinal screening.
Facile regiospecific syntheses of N‐α,N‐1(τ)‐dialkyl‐l‐histidines
Authors: Nayak Surendra Kumar , Monga Vikramdeep , Kaur Navneet , Jain Rahul 
Published: March 2009

Abstractmagnified imageTwo diverse methodologies describe the first synthesis of suitably protected N‐α,N‐1(τ)‐dialkyl‐Lhistidine derivatives. Synthesis of suitably protected N‐α,N‐1(τ)‐dialkyl‐L‐histidines 7‐9 containing different alkyl groups at the N‐α and N‐1(τ) positions was achieved in four steps starting from L‐histidine methyl ester. Whereas, in the one‐step alternate route N‐α‐Boc‐L‐histidine methyl ester upon direct and simultaneous N‐α and N‐1(τ) alkylation with various alkyl halides in the presence of sodium hydride in DMF easily afforded N‐α,N‐1(τ)‐dialkyl‐L‐histidines 14 containing identical alkyl group at the N‐α and N‐1(τ) positions in high yields. Both procedures allowed facile entry to methyl and other higher alkyl groups at the N‐α‐position of the histidine ring
An unusual picoline derivative from the trifluoroacetolysis of thiostrepton
Authors: Merritt Eleanor A. , Bagley Mark C. 
Published: March 2009

Abstractmagnified imageTrifluoroacetolysis of thiostrepton followed by treatment with methanol and aqueous sodium hydroxide led to the formation of N‐(2‐picolinoyl)serine methyl ester, the first pyridine‐containing compound isolated from the chemical degradation of thiostrepton.
The synthesis of a linear tröger's base derived from naphthalene: 7H‐15H‐6,14‐methanodinaphtho[2,3‐b:2′,3′‐f][1,5]diazocine
Authors: Pardo Carmen , Pirat Céline , Elguero José 
Published: March 2009

Abstractmagnified imageThe title compound 3 was prepared in four steps from commercial 3‐amino‐2‐naphthoic acid in an overall 75 % yield. Attempts to use the same approach in the case of 2‐aminonicotinic acid methyl ester failed. All the compounds were characterized by NMR.
Synthesis of 5‐Hydroxy‐2‐(naphth‐2‐yl)chromone derivatives
Authors: Patoilo Diana T. , Silva Artur M. S. , Pinto Diana C. G. A. , Tomé Augusto C. , Cavaleiro José A. S. 
Published: March 2009

Abstractmagnified imageThe Diels‐Alder reaction of 5‐hydroxy‐2‐styrylchromones withortho‐benzoquinodimethane, generated “in situ” by thermal extrusion of sulfur dioxide from 1,3‐dihydrobenzo[c]thiophene 2,2‐dioxide, leads to 2‐(3‐aryl‐1,2,3,4‐tetrahydronaphth‐2‐yl)‐5‐hydroxychromones. These cycloadducts were dehydrogenated with DDQ, using classical thermal reflux conditions and microwave irradiation, affording the corresponding 2‐(3‐arylnaphth‐2‐yl)‐5‐hydroxychromones in high yields (48‐96%).
Rapid and efficient microwave assisted method for the regioselective synthesis of 8,8′‐methylene‐bis‐4‐oxo‐1H and 2H‐chromeno[4,3‐C]pyrazoles
Authors: Nagaraj Adki , Reddy Cherkupally Sanjeeva 
Published: March 2009

Abstractmagnified imageThe ethyl ester of 5,5′‐methylene‐bis‐salicyclic acid 3 was prepared by the esterification of 5,5′‐methylene‐bis‐salicylic acid 2. The compound 3 on reacting with ethylacetoacetate yields 6,6′‐methylenebis‐(3‐acetyl‐4‐hydroxycoumarin) 4. The compound 4 was regioselectively converted into either 8,8′‐methylene‐bis‐(4‐oxo‐1H‐chromeno[4,3‐c]pyrazoles) 6 or 8,8′‐methylene‐bis(‐4‐oxo‐2H‐chromeno[4,3‐c]‐pyrazoles) 7 under microwave irradiation. High yields are achieved even on a gram scale, while reaction times are considerably shortened compared to conventional heating conditions.
Stereochemistry of 1,3‐dipolar‐cycloaddition of 3,4‐dihydroisoquinoline‐ and 3,4‐dihydro‐carboline‐N‐methoxycarbonyl‐ and N‐phenacyl‐methylides with maleic and fumaric nitrile
Authors: Kádas István , Szántó Gábor , Tőke László , Simon AndrÁS , Tóth Gábor 
Published: March 2009

Abstractmagnified imageThe 1,3‐dipolar‐cycloadditions of two kind of isoquinolinium and carbolinium ylides with fumaric and maleic nitrile resulted in pyrroloisoquinoline and indolizino[8,7‐b]indole derivatives, respectively, which are analogues of biologically active alkaloids. The cycloadditions were performed in good yield and proved to be stereoselective. The structure elucidation and complete 1H and 13C assignments have been achieved by a combination of various one‐ and two‐dimensional NMR experiments.
Synthesis of N‐benzoylamino‐1,2,3,6‐tetrahydropyridine derivatives as potential anti‐inflammatory agents
Authors: Mochona Bereket , Redda Kinfe K. 
Published: March 2009

Abstractmagnified imageN‐Benzoylamino‐1,2,3,6‐tetrahydropyridines 9a‐q were synthesized from 4‐substituted pyridines in four steps. Amination of pyridines was carried out to prepare intermediate N‐aminopyridinium mesylates using mesytelenesulfonyl hydroxmate (MSH) as aminating agent. N‐aminopyridinium mestylates reacted with appropriately substituted acyl chlorides to form N‐ylides as stable crystalline solids. Partial reduction of N‐ylides with mild reducing agent afforded N‐benzoylamino‐1,2,3,6‐tetrahydropyridines in fair to good yields.
Synthesis and chemistry of N‐arylated pyrano[2,3‐c]pyrazoles
Authors: Samaritoni J. Geno , Thornburgh Scott , Graupner Paul R. , Cooper David H. 
Published: March 2009

Abstractmagnified imageNovel N2‐arylated pyrano[2,3‐c]pyrazol‐6‐ones 2 can be prepared in a selective manner by generating the anion of 1 (RH) with lithium hexamethyldisilazide in DMF and quenching with activated aryl halides. Sterically demanding groups such as phenyl as in 5 reduce reactivity significantly while electronwithdrawing substituents such as trifluoromethyl and phenyl at C4 of the pyranone ring as in 10 and 15 render the pyranone carbonyl particularly susceptible to attack by nucleophiles resulting in ring‐opening to give novel crotonyl derivatives. Proof of structure required a variety of nmr methods involving proton, carbon, and nitrogen nuclei.
Synthesis of 4‐amino‐5,6,7,8‐tetrahydrothieno[2,3‐b]quinolin‐5‐ol derivatives
Authors: Song Yang‐Heon , Seo Jinmoo 
Published: March 2009

Abstractmagnified imageThis paper describes the synthesis of 4‐amino‐5,6,7,8‐tetrahydrothieno[2,3‐b]quinolin‐5‐ol derivatives (3a‐h) and 4‐amino‐5,6,7,8‐tetrahydrothieno[2,3‐b]quinoline (8a) in good yield by three‐step procedures starting from 2‐aminothiophene‐3‐carbonitrile and 5‐substituted cyclohexane‐1,3‐dione.
Synthesis of benzo[b][1,4]thiazepines by the reaction of 3‐aryl‐1‐(3‐coumarinyl)propen‐1‐ones with 2‐aminothiophenol
Authors: Lévai Albert , Jekő József , Gondos Tímea , Simon András , Tóth Gábor 
Published: March 2009

Abstractmagnified image3‐(2‐Aryl‐2,3‐dihydro‐benzo[b][1,4]thiazepin‐4‐yl)chromen‐2‐ones (2a, e, f) and (Z)‐3‐(2,3‐dihydro‐2‐arylbenzo[b][1,4]thiazepin‐4(5H)‐ylidene)chroman‐2‐ones (3a‐f) have been synthesized by the reaction of 3‐aryl‐1‐(3‐coumarinyl)propen‐1‐ones (1a‐f) with 2‐aminothiophenol in a hot mixture of toluene and acetic acid. Structures of all new compounds and their complete 1H and 13C assignments were achieved applying different one‐ and two‐dimensional nmr experiments in combination with various spectroscopic techniques.
Synthesis of novel benzo‐substituted macrocyclic schiff bases containing two triazole rings
Authors: Elwahy Ahmed H. M. , Masaret Ghada S. 
Published: March 2009

Abstractmagnified imageA synthesis of a series of novel macrocyclic Schiff bases containing two triazole rings 10a,b, 11a,b, 34‐37 in good yields by heating the appropriate bis‐amines 1f, 6a,b, 31 with the corresponding bis‐aldehydes 2, 9a,b, 29 in refluxing acetic acid under high dilution conditions was described. Attempts to synthesize macrocyclic Schiff bases containing pyridine and two triazole rings were also described.
Synthesis and spectroscopic properties of isomeric trideuterio‐ and tetradeuterio pyridines
Authors: Pavlik James W. , Laohhasurayotin Somchoke 
Published: March 2009

Abstractmagnified imageThe syntheses of the six possible isomeric trideuteriopyridines and the three possible isomeric tetradeuteriopyridines are described. These deuteriopyridines were characterized by their mass and NMR spectra.
Synthesis of quinazolinophanes containing bridgehead nitrogen atoms from quinazoline‐2,4(1H, 3H)‐dione
Authors: Sharam R. L. , Singh Jasbir , Kumar Surinder , Kour Daljeet , Sachar Anand , Shallu  , Poonam  , Bhawana  
Published: March 2009

Abstractmagnified imageQuinazoline‐2,4(1H,3H)‐dione (1) reacts with α,ω‐dihaloalkanes to generate three types of quinazolinophanes. When the number of carbon atoms in the dihaloalkanes is 9, a mixture of all the three types of quinazolinophanes (2), (3) and (4) was produced; and when the number of carbon atoms in the dihaloalkane used is from 4 to 7, a mixture of only two types of quinazolinophanes (2) and (3) were produced. When the number of carbon atoms of the dihaloalkane used is odd (5, 7 and 9), the different structural types of quinazolinophanes produced were easily identifiable and distinguishable on the basis of 13C NMR and mass spectral data.
Synthesis of 2‐substituted benzimidazoles by iodine‐mediated condensation of orthoesters with 1,2‐phenylenediamines
Authors: Zhang Zhan‐Hui , Li Jian‐Jiong , Gao Yuan‐Zhe , Liu Yu‐Heng 
Published: March 2009

Abstractmagnified imageIodine was found to be an efficient catalyst for the synthesis of 2‐substituted benzimidazoles by the condensation of orthoesters and 1,2‐phenylenediamines in good to excellent yields under mild reaction conditions.
A novel synthesis of benzo[h]quinolines and study of their fluorescence properties
Authors: Jachak Madhukar N. , Kendre Dhananjay B. , Avhale A. B. , Toche Raghunath B. , Sabnis Ram W. 
Published: March 2009

Abstractmagnified imageAn elegant synthesis of highly fluorescent benzo[h]quinolines have been accomplished from readily available and highly economical 6‐methoxy‐1‐tetralone in high purity and excellent yield.
New one step synthesis of 3,5‐disubstituted 1,2,4‐oxadiazoles
Authors: Outirite Moha , Lebrini Mounim , Lagrenée Michel , Bentiss Fouad 
Published: March 2009

Abstractmagnified imageDisubstituted 1,2,4‐oxadiazoles have been synthesized in good yields and good purity in one pot procedure by reaction of aromatic nitriles, hydroxylamine hydrochloride and sodium carbonate in ethylene glycol under heating at 195°C. The structures of different 1,2,4‐oxadiazoles obtained were confirmed by 1H, 13C NMR and mass spectroscopy.
Retro‐ene reactions in heterocyclic synthesis. v. a novel synthetic method for 1,3,5‐triazine‐2,4(1H,3H)‐diones
Authors: Ito The Late Kunio , Sekiguchi Chiharu , Miida Asuka Wakai Hiroyuki , Ihara Shogo 
Published: March 2009

Abstractmagnified imageN‐t‐Butylamidines 1 on heating with diphenyl carbonate (2) at 150‐180° gave the 1,3,5‐triazine‐2,4(1H,3H)‐dione derivatives 5. Acylation of amidines 1 and cyclocondensation of the resulting carbamates 3 gave [1,3,5,7]tetrazocine‐2,6‐dione derivatives 4, and subsequent retro‐ene reaction and ring contraction afforded triazine derivatives 5.
An alternate approach for the synthesis of 2‐substituted‐arylimidazo[4,5‐b]pyridines and their anti‐bacterial activity
Authors: Ramanatham Vinodkumar , Chari Murugulla Adharvana , Dubey Pramod Kumar 
Published: March 2009

Abstractmagnified imageAn alternate method for the convenient preparation of the imidazo[4,5‐b]pyridines from 2,3‐pyridinediamine and 2‐aryl‐3(1)‐benzoxazine‐4H‐one has been illustrated. The mechanistic pathway for the formation of the product 4 has been proposed. All the compounds prepared herein were screened for their anti‐ bacterial properties.
Oxidative coupling of acridinones: Synthesis of new C2‐symmetry atropisomers
Authors: Scarpellini‐Charras Karine , Boyer Gérard , Filloux Nathalie , Galy Jean‐Pierre 
Published: March 2009

Abstractmagnified imageThe preparation of symmetric 2,2′‐dimethoxy‐10,10′‐biacridinyl‐9,9′‐dione atropisomers were obtained by the oxidative coupling of 9(10H)‐acridinone with 1,3‐dibromo‐5,5‐dimethyl‐imidazolidine‐2,4‐dione
Synthesis of new heterocyclic compounds having 1,2,3‐triazole and isoxazole rings in a single molecule
Authors: Chen Qiu , Liu Fangming , Xu Feng , Yang Chun 
Published: March 2009

Abstractmagnified imageFive series of new heterocyclic compounds of 1,2,4‐triazole Mannich bases, 1,3,4‐oxadiazole Mannich bases, 1,3,4‐oxadiazolines, 1,2,4‐triazolo[3,4‐b]1,3,4‐thiadiazines and 1,2,4‐triazolo[3,4‐b]1,3,4‐thiadiazoles, in which 1,2,3‐triazolyl and isoxazolyl have been united, were synthesized from the intermediate of 5‐methyl‐3‐(2‐phenyl‐2H‐1,2,3‐triazol‐4‐yl)isoxazole‐4‐carbohydrazide, Their structures were established by spectroscopy.
Highly stereoselective synthesis of cyclopropyl heterocycles via cyclopropanation of olefin with arsonium salt
Authors: Ren Zhongjiao , Cao Weiguo , Tong Weiqi , Chen Jie , Wang Changqing 
Published: March 2009

Abstractmagnified imageAn efficient and highly stereoselective approach for the preparation of highly functionalized cyclopropyl heterocycles via the cyclopropanation of olefines with arsonium salts in the presence of KF2H2O has been developed.
A facile and general synthesis of 2,4‐Di‐ and 2,4,7‐trisubstituted thieno[2,3‐c]pyridines
Authors: Zhu Gui‐Dong , Gunawardana Indrani W. , Boyd Steven A. , Melcher Laura M. 
Published: March 2009

Abstractmagnified imageTreatment of 3,5‐dibromo‐ or 3,5‐dichloro‐pyridine‐4‐carboxaldehyde 2 with one equivalent of methyl thioglycolate, followed by exposure to base, provided 4‐bromo‐ or 4‐chloro‐thieno[2,3‐c]pyridine‐2‐carboxylate 4 in good yields. Oxidation of the thieno[2,3‐c]pyridine scaffold such as 7 with mCPBA, followed by treatment with POBr3, introduced a bromine exclusively at the 7‐position of the heterocycle. The 4‐ or 7‐bromide of the thienopyridines readily underwent Suzuki, Stille coupling, and Buchwald amination reactions, to afford 4‐ or 7‐substituted analogs 6 or 11. The 2‐carboxylate of 4b or 12 was smoothly removed through saponification and decarboxylation to furnish 15 or 16. Deprotonation of the thienopyridine at C‐2 position, followed by trapping with trimethyltin chloride, afforded a 2‐stannyl analog, which was readily converted to other C‐2 derivatives via Stille reaction.
A new thermal study of the reaction of 6‐azidopyridones with different amines and hydrazines
Authors: Mekheimer Ramadan Ahmed , El‐Hameid Afaf Mohamed Abd , Sadek Kamal U. 
Published: March 2009

Abstractmagnified imageReacting of 6‐azidopyridone derivatives 1 with o‐phenylenediamine (2a) in chloroform at room temperature afforded the new azidopyridones 3. However, its fusion with 2a,b at 100–110°C gave the interesting pyrido[2,3‐b][1,5]diazepines 4a,b. Alternatively, compound 4a could also be obtained by heating azidopyridones 3 at 100–110°C. When compound 1 was allowed to react with hydrazines 7a‐d at room temperature it gave the corresponding azido compounds 8a‐d. Fusion of 1 with phenylhydrazine (7d) at 140–160°C afforded the new aminopyridones 10. The 6‐azidopyridones 1 could also be converted to the corresponding 6‐alkylaminopyridones 15a‐d by reaction with an excess of alkylamines at room temperature.
Synthesis of enantiomerically pure fire ant venom alkaloids: Solenopsins and isosolenopsins A, B and C
Authors: Bandara Herath H. M. T. , Dhammika Nanayakkara N. P. 
Published: March 2009

Abstractmagnified imageConcise and efficient methods for the synthesis of enantiomers of fire ant venom alkaloids solenopsin and isosolenopsin A, B, and C are described. These syntheses are based on diastereoselective electrophilic substitution of enatiomerically‐pure α‐lithiated 2‐alkylpiperidine.
Reactions of tetrachloropyridazine with aliphatic nitrogen nucleophiles
Authors: Pattison Graham , Sandford Graham , Wallace Emma V.B. , Yufit Dmitry S. , Howard Judith A.K. , Christopher John A. , Miller David D. 
Published: March 2009

Abstractmagnified imageNucleophilic aromatic substitution reactions of tetrachloropyridazine with a series of aliphatic primary and secondary amines led selectively to products arising from replacement of chlorine at the 4‐position in all cases. The structures of the products were unambiguously confirmed by X‐ray crystallography. Substitution occurs at the most activated site para to ring nitrogen, despite the possible steric hindrance to substitution by adjacent chlorine atoms, reflecting the activating influence of ring nitrogen meta to the site of attack. N,N′‐Dimethylethylene diamine gave a mixture of [6,6] ring fused products following initial substitution at the 4‐position.
Preparation and evaluation of N‐sulfinyl dienophiles for asymmetric hetero‐diels‐alder reactions
Authors: Endeshaw Molla Mellese , Hansen Lars K. , Gautun Odd R. 
Published: March 2009

Abstractmagnified imageA series of N‐sulfinyl dienophiles 1c‐i has been screened in asymmetric hetero‐Diels‐Alder reactions using chiral bis(oxazoline)copper(II) and ‐zinc(II) triflates. The survey pointed out N‐sulfine 1c (R  P(O)(OPh)2) as the most promising N‐sulfine regarding yield and stereoselectivity (up to 97% ee). The relative configurations, and in one case the absolute configuration, of the HDA adducts were established by X‐ray analysis.
Carbazolo[2,1‐a]carbazole derivatives via fischer indole synthesis
Authors: Dufour Fabien , Kirsch Gilbert 
Published: March 2009

Abstractmagnified imageA series of new carbazolo[2,1‐a]carbazoles was synthesized from 4‐oxo‐1,2,3,4‐tetrahydrobenzo[a]‐carbazole derivatives.
Simple synthesis of 2‐amino‐4‐(het)aryl‐4,6‐dihydro‐1(3)(11)H‐[1,3,5]triazino[2,1‐b]quinazolin‐6‐ones
Authors: Dolzhenko Anton V. , Dolzhenko Anna V. , Chui Wai‐Keung 
Published: March 2009

Abstractmagnified imageThe 2‐amino‐4‐(het)aryl‐4,6‐dihydro‐1(3)(11)H‐[1,3,5]triazino[2,1‐b]quinazolin‐6‐ones were prepared readily by cyclocondensation of anthranilic acid derived 4‐oxo‐3,4‐dihydroquinazolinyl‐2‐guanidine with a variety of aldehydes. The structures of the compounds were confirmed by nmr spectroscopy, including 2D NOESY experiments.
tert‐Amino effect at a coumarin and a 2‐quinolone system: Synthesis of 1,2 fused 5H‐chromeno[4,3‐b]pyridin‐5‐ones and a 6H‐benzo[h][1,6]naphthyridin‐5‐one
Authors: Ivanov Ivo C. , Glasnov Toma N. , Belaj Ferdinand 
Published: March 2009

Abstractmagnified imageSome novel 1,2‐fused 5H‐chromeno[4,3‐b]pyridin‐5‐ones (5a,b) and a 6H‐benzo[h][1,6]naphthyridin‐5‐one (5c) have been synthesized starting from the 4‐chlorocoumarin‐3‐carbaldehyde (1a) or its N‐methyl‐2‐quinolone analogue (1b) via subsequent Knoevenagel condensation and ring closure reaction known as the ‘tert‐amino effect’. These are rare examples of the tert‐amino effect occurring at 2‐pyrone and 2‐pyridone ring. An unusual intramolecular redox reaction of the iminium ion 6, reported earlier, most probably follows analogous mechanism as the tert‐amino effect reactions leading to 5.
Synthesis of novel 5‐chlorinated 2‐aminothiophenes using 2,5‐dimethylpyrrole as an amine protecting group
Authors: Puterová Zita , Bobula Tomáš , Végh Daniel 
Published: March 2009

Abstractmagnified imageA new synthetic methodology towards substituted 2‐amino‐5‐chlorothiophenes is described. Compounds of this type are important as building blocks for oligomers used in polymer research. Easily available 2‐aminothiophenes underwent Paal‐Knorr reaction to protect the free amino group before electrophilic substitution. Although the chlorination was predicted to proceed at the thiophene ring, only free positions of 2,5‐dimethylpyrrole were substituted. To direct chlorination to the thiophene ring acetamido derivative was prepared first and then chlorinated. Transamination with hexane‐2,5‐dione created a 2,5‐dimethyl pyrrole ring from the acetamido group. In the final step, after treatment with hydroxylamine dihydrochloride, the pyrrole ring is removed and a free amino group is regenerated.
The synthesis of cyclic and acyclic long‐chain arylpiperazine derivatives of salicylamide as serotonin receptor ligands
Authors: Kowalski Piotr , Jaśkowska Jolanta , Bojarski Andrzej J. , Duszyńska Beata 
Published: March 2009

Abstractmagnified imageThe 1‐arylpiperazine series ofN‐substituted 1,3‐benzoxazine‐2,4‐diones as well asO‐ andN‐substituted salicylamides with ann‐propyl chain were synthesized in order to explore the effect of cyclic and acyclic salicylamide moieties on their binding affinity for 5‐HT1A, 5‐HT2Aand 5‐HT7receptor sites. Target compounds1and2were prepared by a two‐step procedure,i.e.by alkylation of 1,3‐benzoxazine‐2,4‐dione or salicylamide with 1,3‐dibromopropane and next by condensation of 3‐bromopropyl intermediates with arylpiperazines; syntheses of 3‐bromopropyl intermediates were performed in solvent‐free conditions. Compounds3were prepared by hydrolysis of1. In respect of salicylamide moieties, binding affinities for 5‐HT1Aand 5‐HT7receptors increase according to the rank of derivatives3<1<2, for the same arylpiperazines. Regarding 5‐HT2Areceptors, increased activity of ligands was changed in reverse order to the affinity for 5‐HT1A,i.e.2<1<3. 5‐HT1Aand 5‐HT7receptor binding constants were the highest for the 2‐methoxyphenyl ligand2c, while the 3‐chlorophenyl ligand3bwas most active for 5‐HT2Areceptors.
Synthesis and structural study of a new series of 2‐methylsulfanyl‐tetrahydropyrimidines from β‐alkoxyvinyl trihalomethyl ketones
Authors: Zanatta Nilo , Madruga Claudia C. , Marisco Patricia C. , Da Rosa Luciana S. , Fernandes Liana Da S. , Flores Darlene C. , Flores Alex F. C. , Burrow Robert A. , Bonacorso Helio G. , Martins Marcos A P. 
Published: March 2009

Abstractmagnified imageThis work describes the synthesis of a novel series of 2‐methylsulfanyl‐tetrahydropyrimidines, from the cyclocondensation reaction of β‐alkoxyvinyl trihalomethyl ketones with 2‐methyl‐2‐thiopseudourea sulfate, in good yields. A detailed 1H‐ and 13C‐NMR study was performed on the 2‐methylsulfanyl‐tetrahydropyrimidines obtained and 3D structures were proposed based on AM1 calculations supported by 1H NMR coupling constants and NOESY experiments.
Claisen Condensation ofN‐Methylpyrrolidinone and α‐Chloronicotinic esters
Authors: Kaminski Thomas , Kirsch Gilbert 
Published: March 2009

Abstractmagnified imageReaction between α‐halo‐nicotinic esters and a nucleophilic source such as theN‐methylpyrrolidin‐2‐one (NMP) gave unexpected results. The presence of the halide on the pyridine gave a very interesting migration reaction. Extension to 6‐methylnicotinic ester derivatives lead to an unexpected carbanion condensation.
Enantioselective 1,3‐dipolar cycloaddition reactions using complexes of (−)‐sparteine
Authors: Gucma Mirosław , Marek Gołȩbiewski W. 
Published: March 2009

Abstractmagnified imageRegio‐ and stereoselective 1,3‐dipolar cycloaddition of nitrile oxides to internal 2‐pentenols and α,β‐unsaturated esters catalyzed by (−) sparteine‐lanthanide complexes affords corresponding 3‐aryl‐2‐isoxazolines with enantioselectivities up to 68% ee.
Room temperature facile synthesis of quinoxalines catalyzed by amidosulfonic acid
Authors: Li Zhenjiang , Li Weisi , Sun Yingjie , Huang He , Ouyang Pingkai 
Published: March 2009

Abstractmagnified imageAmidosulfonic acid NH2–SO3H catalyzed direct condensations of o‐phenylenediamines with α‐diketones at room temperature in organic solvents to afford quinoxalines in excellent yields. The amidosulfonic acid as a solid acid catalyst in this preparation was efficient and recoverable.