bluuebunny/crossref_metadata_2025 huggingface dataset:
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

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The 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

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Novel 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.
Design and synthesis of new and significative bifunctional compounds containing two pyrazolo[3,4‐b]pyridine nucleis through multicomponent reaction under microwave irradiation
Authors: Tu Shujiang , Wang Qian , Zhang Yan , Xu Jianing , Zhang Jinpeng , Zhu Xiaotong , Shi Feng
Published: March 2009

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A series of new and significative bifunctional compounds containing two pyrazolo[3,4‐b]pyridine moieties has been synthesized through a rapid one‐pot three‐component reaction of dialdehyde, 5‐amino‐3‐methyl‐1‐phenylpyrazole and active methylene compounds in glycol under microwave irradiation without catalyst. The method has the advantages of good yield (85‐98%), short route and reaction time (45‐300s), wide reaction scope and easy work‐up procedure.
Mn(III) acetate mediated diasteroselective [3+2] oxidative addition of 1,3‐dicarbonyl compounds with chalcones
Authors: Shanmugam Pachiappa N. , Kumar Kalv I. Hemanth , Perumal Paramasiva N. T.
Published: March 2009

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A diastereoselective synthesis of 4,5‐dihydrofurans by oxidative addition of 1,3‐dicarbonyl compounds with chalcones mediated by Mn(OAc)3 in moderate to good yields is reported.
Syntheses, electrochemical studies and crystal structures of new unsymmetrical tetrathiafulvalene carboxylate derivatives
Authors: Liu Wei , Guo Yun‐Jun , Zuo Jing‐Lin , You Xiao‐Zeng , Zeng Xi‐Rui
Published: March 2009

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A series of new unsymmetrical tetrathiafulvalene carboxylate derivatives (7‐11) were synthesized and characterized by NMR, MS, electrochemical studies and X‐ray crystal structural determination. Compound 8 showed obvious changes in redox peak potentials as the concentration of p‐toluenesulfonic acid changes.
The first synthesis of furazano[3,4‐b][1,6]naphthyridines
Authors: Vasilev Leonid S. , Sheremetev Aleksei B. , Dorokhov Vladimir A. , Suponitsky Kyrill Yu.
Published: March 2009

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Reaction of 6‐acetyl‐7‐aminofurazano[3,4‐b]pyridines with DMFDMA afforded N,N‐dimethylformamidines that were cyclized to the novel furazan‐fused [1,6]naphthyridine system by treatment with sodium methylate in good yield. The tricyclic system is characterized by X‐ray crystallography.
A novel photoisomerzation of 1,2‐benzothiazine 1,1‐dioxides to 1,3‐benzothiazine 1,1‐dioxides
Authors: Elghamry Ibrahim , Döpp Dietrich , Henkel Gerald
Published: March 2009

A novel facile photoconversion of 4‐hydroxy‐1,2‐bezothiazine 1,1‐dioxides (3a‐e) into 4‐oxo‐1,3‐2H‐benzothiazine 1,1‐dioxides (4a‐e) and 4‐hydroxy‐2‐methyl‐N‐(pyridin‐2‐yl)‐2H‐1,2‐benzothiazine‐3‐carboxamide 1,1‐dioxide (PRX) into N‐methyl saccharin (2) upon 254 nm irradiation in methanol or acetonitrile is reported. The structures of the products have been elucidated by spectroscopic methods and single crystal X‐ray structure determination for 4a and 4d.
Synthesis of thiophene/phenylene co‐oligomers. V. Functionalization at molecular terminals toward optoelectronic device applications
Authors: Katagiri Toshifumi , Ota Satoshi , Ohira Takayuki , Yamao Takeshi , Hotta Shu
Published: March 2009

We report the synthesis of various thiophene/phenylene co‐oligomers with a total number of thiophene and benzene (phenylene) rings of 5 and 6 with various terminal groups. Those terminal groups have been chosen from among alkyl groups, methoxy groups, trifluoromethyl groups, and cyano groups. The molecular backbone of these compounds comprises phenyl‐ or biphenylyl‐capped thiophene (or oligothiophene) or an alternating co‐oligomer. The synthesis is based on either the Suzuki coupling reaction or the Negishi coupling reaction. These reaction schemes enabled us to obtain the target compounds in high quality. In particular, the latter coupling method turned out to produce the compounds at a high yield. The terminal groups are expected to produce various functionalities based upon their electron donating character (alkyl groups and methoxy groups) or electron withdrawing character (trifluoromethyl groups and cyano groups). Additionally some of these groups bring about enhanced solubility. This will lead to the production of a diversity of modified compounds of thiophene/phenylene co‐oligomers. To give an example that demonstrates usefulness of the target compounds, we present optoelectronic data that are associated with their device applications.
Microwave assisted synthesis of coumarins via potassium carbonate catalyzed knoevenagel condensation in 1‐n‐butyl‐3‐methylimidazolium bromide ionic liquid
Authors: Valizadeh Hassan , Gholipur H. , Shockravi Abbas
Published: March 2009

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A variety of substituted coumarins have been prepared via an inexpensive and efficient potassium carbonate catalyzed Knoevenagel condensation of salisylaldehydes with acidic methylene compounds in ionic liquid media. 1‐n‐Butyl‐3‐methylimidazolium bromide has been employed as an alternative reaction medium in this procedure. The reaction proceeds smoothly under mild and solvent‐free conditions and the products are obtained in excellent yields. Mild reaction conditions and good to excellent yields of the products are the noteworthy advantages of the method.
Synthesis of 7a‐aryl‐5‐t‐butyl‐3‐methyleneoctahydrobenzofuran possessing partial skelotons of some santonin analogue and furanolignans by intramolecular radical cyclisation reaction
Authors: Periasamy Marappagounder , Ponnuswamy Alagusundaram
Published: March 2009

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Bicyclic octahydrobenzofuran derivatives (1c‐6c) possessing the partial skeletons of santonin (7), 11,13‐dehydroisohyposantonin (8), dihydrosesamin (9) and lariciresinol (10) have been synthesised by intramolecular radical cyclisation in good yield via the precursors viz., the trans diaxial bromopropynyl ethers (1b‐6b) obtained in highly regio/stereoselective manner.
Green chemistry approach to the synthesis of 2‐amino‐4‐aryl‐6‐ferrocenyl‐pyridine derivatives by a one‐pot reaction in aqueous medium
Authors: Zhuang Qiya , Jia Runhong , Tu Shujiang , Zhang Junyong , Jiang Bo , Zhang Yan , Yao Changsheng
Published: March 2009

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A clean and facile green chemistry method for the synthesis of a series of 2‐amino‐4‐aryl‐6‐ferrocenylpyridine derivatives was afforded. The products were synthesized via the one‐pot reaction of aromatic aldehyde, malononitrile or ethyl cyanoacetate, acetylferrocene and ammonium acetate in aqueous medium under microwave irradiation and conventional heating conditions without catalyst. This method had several advantages such as higher yield, lower cost, reduced environmental impact, and convenient procedure.
Synthesis and NMR analysis of spiranic heterocycles from carbohydrate derivatives
Authors: Alho Miriam A. Martins , D'Accorso Norma B.
Published: March 2009

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We report the synthesis of some furanose and pyranose acylhydrazones and their heterocyclization products. The new compounds were characterized physically and spectroscopically and the syn‐anti and (R)‐(S) configuration was determined by NOESY experiments. We discuss the influence of the nucleophile, the temperature and the precursor structure on the heterocyclization products.
Synthesis and antitumor activities of 2‐(substituted)phenyl‐1,2,4‐triazolo[1,5‐a]pyridines
Authors: Zhang Guolin , Hu Yongzhou
Published: March 2009

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Twenty‐three 2‐(substituted)phenyl‐1,2,4‐triazolo[1,5‐a]pyridines have been synthesized by cycloadditison reaction between N‐amino methylpyridinium mesitylenesulfonates and substituted benzonitriles under the presence of potassium hydroxide at room temperature. The structures of all products were confirmed by 1H NMR, MS and elemental analyses. The antitumor activities of these compounds were evaluated against human ovary cancer cell line (HO‐8910) in vitro by MTT method. The preliminary results showed that compound 1e (IC50 28μM) and compound 1w (IC50 31μM) exhibited stronger antitumor activities than cisplatin (IC50 35μM) in vitro. Hence, 1e and 1w have potential antitumor activities and are worth further investigation.
Synthesis of a novel diazepine
Authors: Memoli Kevin A.
Published: March 2009

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A novel pyrrolopyridodiazepine ring system was synthesized from methyl 2‐methyl nicotinate.
Syntheses of acyclic C‐glycosidic derivatives of 1,2,4‐triazoles by cycloadditions of 1‐aza‐2‐azoniaallene salts to D‐glucononitrile‐2,3,4,5,6‐pentaacetate
Authors: Hassan N. A.
Published: March 2009

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Reported are preparations of acyclic derivatives of 1,2,4‐triazole‐5‐glycosidies 9 by cycloadditions of 1‐aza‐2‐azonia‐allene salts 3 to the nitrile group of D‐glucononitrile‐2,3,4,5,6‐pentaacetate 5 affording triazolium salts 8, which with aqueous sodium hydogencarbonate are hydrolyzed to 9. Deacetylation of compounds 9 produced the C‐glycosides 10.
Studies with enamines and azaenamines: Synthesis and reactivity of 3‐dimethylamino‐2‐[(3‐indolyl) carbonyl]propenonitrile
Authors: Abdallah Tayseer A.
Published: March 2009

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2‐Oxo‐3‐(indol‐3‐yl)propanonitrile 2 condensed with dimethylformamide dimethylacetal to yield the enaminonitrile 3. The latter reacted with 4‐chloroaniline to yield the 4‐chlorophenylaminoacrylonitrile 5. Reaction of 3 with hydrazine hydrate led to formation of pyrazole‐4‐carbonitrile 6. Compound 3 reacted with ethyl acetoacetate in refluxing acetic acid and in presence of ammonium acetate to yield the indolylpyridine 10. Enamine 3 reacted with 5(1H)‐aminotriazole 13 and 3(5)‐aminopyrazole 17 to yield the pyrimidine derivatives 15 and 19, respectively.
Microwave‐induced perchloric acid catalyzed novel solvent‐free synthesis of 4‐aryl‐3,4‐dihydropyrimidones via biginelli condensation
Authors: Mukhopadhyay Chhanda , Datta Arup , Banik Bimal K.
Published: March 2009

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We report here domestic microwave‐induced perchloric acid‐catalyzed solvent‐free synthesis of various 4‐aryl‐3,4‐dihydropyrimidones for the first time. In all the cases the yields are excellent and the mechanism follows a simple Biginelli condensation to produce the dihydropyrimidones in a few seconds. This procedure has been successfully employed to synthesize the mitotic kinesin EG5 inhibitor Monastrol (Figure I).
Pyrolytic behavior of substituted N‐aminoheteroaromatics: Synthesis of pyrazolo[1,5‐a]pyridine and 3‐substituted 3‐oxopropionitrile derivatives
Authors: Al‐Awadi Nouria A. , Patel Mehul , Dib Hicham H. , Abdelkhalik Mervat
Published: March 2009

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Flash vacuum pyrolysis (FVP) of 1,7‐bis‐(3‐aroylideneamino)‐4,6,10,12‐tetramethyl‐2,8‐dioxo‐1,7‐diazacyclododeca‐3,5,9,11‐tetraene‐3,9‐dicarbonitriles 11a‐c at 650°C and 0.02 Torr yielded 5,7‐dimethyl‐3‐(4‐methylbenzoyl)‐pyrazolo[1,5‐a]pyridine‐4‐carbonitrile 14, 4,6‐dimethyl‐2‐oxo‐1,2‐dihydropyridine‐3‐carbonitrile 16 and 3‐aryl‐3‐oxo‐propionitriles 17a,b. A plausible mechanism is suggested to account for the formation of the products.
A convenient route to synthesize 1,2,4‐triazolo[1,5‐a]pyrimidine derivatives and their one and two‐photon absorption spectral properties
Authors: Wang Hongli , Xu Wenyuan , Dai Yi , Zhang Bin , Wu Qiongyou , Zhang Mingzhi , Tian Min , Wu Hong , Wang Dingli
Published: March 2009

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A convenient method for synthesizing α‐(1,2,4‐triazolo[1,5‐a]pyrimidine‐2‐sulfonyl)methane derivatives, 3 and 4, by the well known Knoevenagel reaction, in one step, is described. The two chromophores are stilbene‐type chromophores containing the same D‐π‐A structures and end‐capped with aromatic group as their donors. Measured with femtosecond multipass Ti:sapphire amplifier as irradiation source (pumped by the laser at 800 nm), the two chromophores show efficient two‐photon induced orange red fluorescence emission. The experimental results indicate that the numbers of branches of the two chromophores affect their one‐photon properties and two‐photon up‐conversion emission behaviors, and with the increasing numbers of branches, their wavelengths of λabsmax, λspfmax and λtpfmax exhibit bathochromic shifts.
A novel synthesis of cyclopropyl lactam and amide from cis‐2‐aryl‐3‐benzoyl‐1,1‐dicynocyclopropane with H2O2 in the presence of NaHCO3
Authors: Ren Zhongjiao , Chen Jie , Lu Yeying , Wu Danyi , Cao Weiguo
Published: March 2009

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The process for preparation of cyclopropyl lactam and amide from cis‐2‐aryl‐3‐benzoyl‐1,1‐dicynocyclopropane with H2O2 in the Presence of NaHCO3 is described. The highly stereoselective conversion of monocyano group to amide has been carried out in the present method.
Transformations of phenylhydrazones of 5‐acyl‐1,2,4‐triazines to pyrazolo[4,3‐e][1,2,4]triazines or 4‐cyanopyrazole
Authors: Mojzych Mariusz , Rykowski Andrzej
Published: March 2009

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A simple and high yielding preparation of pyrazolo[4,3‐e][1,2,4]triazines and 4‐cyano‐3‐methyl‐1‐phenylpyrazole derivatives from corresponding phenylhydrazones of 5‐acyl‐1,2,4‐triazines by melt under acidic medium and by thermal heating, respectively.
Synthesis and crystal structure of novel schiff bases derived from 3‐(2‐ethoxyphenyl)‐4‐amino‐5‐mercapto‐4H‐1,2,4‐triazole
Authors: Zhou San‐nu , Zhang Li‐xue , Zhang An‐jiang , Sheng Ji‐shun , Zhang Hai‐le
Published: March 2009

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A series of novel 4‐(arylmethylidene)amino‐5‐(2‐ethoxyphenyl)‐3‐mercapto‐4H‐1,2,4‐triazoles (2a‐f) were easily synthesized in high yields by means of the reactions of 3‐(2‐ethoxyphenyl)‐4‐amino‐5‐mercapto‐4H‐1,2,4‐triazole (1) with various aromatic aldehydes. The compound, 4‐(4‐methylbenzylidene)‐amino‐5‐(2‐ethoxyphenyl)‐3‐mercapto‐4H‐1,2,4‐triazole was investigated with X‐ray crystallography.
Synthesis and antifungal activity of novel 3,6‐diaryl‐5H‐[1,2,4]triazolo[4,3‐b][1,2,4]triazepines
Authors: Gupta Monika
Published: March 2009

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5‐Aryl‐3,4‐diamino‐1,2,4‐triazoles 5 on treatment with β‐chlorocinnamaldehydes 7 in the presence of catalytic amount of p‐TsOH and N,N‐dimethylformamide as an energy transfer medium under microwave irradiation and as solvent with oil‐bath heating at 80 °C affords novel 3,6‐diaryl‐5H‐[1,2,4]triazolo[4,3‐b]‐1,2,4]triazepines 8. The structures of the synthesized compounds were established on the basis of 1H NMR, IR, mass spectral data and elemental analysis.
Ring transformations of heterocyclic compounds. XXV. Phenanthrene aldehyde imines via ring transformation of pyrylium salts with methylenedihydroisoquinolines—A novel access to the phenanthrene skeleton
Authors: Zimmermann Thomas , Krautscheid Harald
Published: March 2009

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The ring transformation of 2,4,6‐triarylpyrylium salts 1 with 2‐methylenedihydroisoquinolines 6, generated in situ from the related 2‐methylisoquinolinium salts 2, in the presence of bases is reported. Whereas the transformation of 1 with 2(6) and sodium methoxide in methanol leads to 2‐(2,4,6‐triarylphenyl)isoquinolinium salts, with sodium ethoxide in ethanol the aryl substituted phenanthrene‐9‐carbaldehyde imines 4 are obtained, the structure of which was confirmed by an X‐ray structure determination of the 1‐(4‐methylphenyl) substituted derivative. Acid catalyzed hydrolysis of the imines 4 gives rise to the parent phenanthrene aldehydes. The transformation 1 + 2(6) → 4 represents a novel access to the phenanthrene skeleton.
Synthesis of new chromeno[4,3,2‐de]quinazolin‐2‐ones, ‐quinazolines and ‐pyrrolo[2,1‐b]quinazolines
Authors: Martínez‐Viturro Carlos M. , Domínguez Domingo
Published: March 2009

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The total synthesis of chromeno[4,3,2‐de]quinazolin‐2‐ones, ‐quinazolines and ‐pyrrolo[2,1‐b]quinazolines from easily prepared 4‐methoxy‐1‐nitro‐9H‐xanthen‐9‐one is reported. These compounds, in which a 1,3‐diazine ring is fused to the xanthene scaffold, were obtained with good overall yields in very few steps.
1,3‐dipolar cycloadditions. Part XII ‐ selective cycloaddition route to 4‐nitroisoxazolidine ring systems
Authors: Banerji Avijit , Gupta Maya , Biswas Pizush Kanti , Prangé Thierry , Neuman Alain
Published: March 2009

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Cycloadditions of C,N‐diarylnitrones to β‐nitrostyrenes occurred to yield two diastereoisomeric cycloadducts, the 3,4‐trans‐4,5‐trans substituted isoxazolidine derivatives being formed selectively as the major products. These were characterised by spectroscopic and X‐ray data. Conformational studies were carried out by X‐ray crystallography and Molecular Modelling.
Reactions of some pyrrole‐2,3‐diones with hydrazine hydrate and o‐phenylenediamine
Authors: Sarıpınar Emin , Karataş Süleyman , İlhan İlhan Özer
Published: March 2009

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2,3‐Dihydro‐1H‐pyrrole‐2,3‐diones 1a‐d react with hydrazine hydrate 2 and o‐phenylenediamine 4 under different conditions to yield the pyrazole‐3‐carboxamide derivatives 3a‐d, the pyrrol‐2‐ones 5a‐d and the quinoxaline‐2‐one derivatives 6a‐d, respectively. Hydrolysis of the quinoxaline‐2‐one derivatives 6a‐d gave a substituted furo[2,3‐b]quinoxaline 7. The structures of the synthesized compounds were assigned on the basis of analytical results as well as spectroscopic data.
A rapid synthesis of new benzene‐centered porphyrin trimers
Authors: Papamicaël Cyril A. , Mongin Olivier , Gossauer Albert
Published: March 2009

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In connection with our study of the capability of forming ordered self‐assembled monolayers on gold substrates, we described the full details concerning the rapid synthesis of two rigid, star‐shaped D3‐symmetric arrays with a benzene core attached to three identical metalloporphyrins containing either ethyldisulfide functions or thienyl groups.
Chemo, stereo, and regioselective addition of α‐(2‐methoxyaryl)‐N‐aryl nitrones to diarylidineacetone: Synthesis of novel isoxazolidines
Authors: Jayapradha Sadaiyan Ramadass , Sridharan Vellaisamy , Muthusubramanian Shanmugam , Polborn Kurt
Published: March 2009

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A new set of 2,3,4,5‐tetrasubstituted isoxazolidines with an α,β‐unsaturated carbonyl function at position 4 has been synthesized. The multicomponent approach and microwave irradiation protocol have also been investigated for the above synthesis.
Regioselective synthesis of polyheterocyclic scaffolds by sequential [3,3] sigmatropic rearrangements and pyridine hydrotribromide mediated heterocyclization
Authors: Majumdar K. C. , Muhuri S.
Published: March 2009

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A number of tetracyclic polyhetero scaffolds have been regioselectively synthesised in 70‐75% yield from 4‐[(3‐aryloxy‐2‐propynyl)oxy]‐6‐methyl‐pyran‐2‐ones via thionation of the lactone carbonyl, sequential Claisen rearrangements and pyridine hydrotribromide mediated heterocyclization.
Base‐promoted rearrangements of ester groups in 3a,7a‐dihydroindole‐2,3,3a,4‐tetraester
Authors: Jeon Kyu Ok , Yu Ji Sook , Lee Chang Kiu
Published: March 2009

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Tetramethyl 3a,7a‐dihydro‐1‐methyl‐1H‐indole‐2,3,3a,4‐tetracarboxylate which is an 1:2 adduct of 1‐methylpyrrole and dimethyl acetylenedicarboxylate underwent isomerization catalyzed by sodium methoxide to form a 5,7a‐dihydro‐1‐methyl‐1H‐indole‐2,3,4,5‐tetracarboxylate, its 5,6‐dihydro isomer, and a ring opening product which is an azonine derivative. Fully aromatized esters such as 1‐methylindole‐2,3,4‐triester, 1‐methylindole‐2,3,4,5‐tetraester and 1‐methyl‐2,3,4,6‐tetraester were also isolated. An indole compound which could be formed by conjugative addition of the methoxide ion was also isolated.
Synthesis of 2‐formyl‐1‐aza‐dibenzo[e,h]azulenes
Authors: Pešić Dijana , Landek Ivana Ozimec , Čikoš Ana , Metelko Biserka , Gabelica Vesna , Stanić Barbara , Merćep Mladen , Mesić Milan
Published: March 2009

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Synthesis of a novel heterocyclic class of compounds, 1‐aza‐dibenzo[e,h]azulenes [1] (6a‐c and 7a‐c), derived from dibenzo[b,f]oxepin, its 8‐chloro analogue and dibenzo[b,f]thiepin, respectively, is described. Aldol condensation of the starting ketones 4a‐c with (dimethyl‐hydrazono)‐acetaldehyde affords hydrazonoethylidene derivatives 5a‐c, which on reduction with sodium dithionite and subsequent cyclization provide the target tetracyclic 1‐aza‐dibenzo[e,h]azulenes 6a‐c. Regiospecific formylation of 6a‐c with Vilsmeier reagent leads to 2‐formyl derivatives 7a‐c. A series of derivatives 6a‐c and 7a‐c was tested for antiinflammatory activity as potential inhibitors of tumor necrosis factor alpha (TNF‐α) production in vitro.
A revised synthetic scheme of 6,6′‐dibromoindirubin
Authors: Tanoue Yasuhiro , Hara Akari , Kai Norihisa , Sakata Kazunori , Hashimoto Mamoru , Nagai Takeshi
Published: March 2009

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The synthetic scheme of 6,6′‐dibromoindirubin (2) was investigated in detail. The reaction of 6‐fluoro‐3‐acetoxyindole (7) with isatin (8) in methanol with Na2CO3 produced 6′‐fluoroindirubin in moderate yields. Its structure determination was mainly undertaken using 1H NMR spectroscopy. On the basis of this result, the synthetic scheme of 2 reported by Cooksey was revised.
Pyrazolo[4′,3′:5,6]pyrano[2,3‐b]quinoxalin‐4(1H)‐one: Synthesis and characterization of a novel tetracyclic ring system
Authors: Eller Gernot A. , Datterl Barbara , Holzer Wolfgang
Published: March 2009

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Derivatives of the hitherto unknown ring system, pyrazolo[4′,3′:5,6]pyrano[2,3‐b]quinoxalin‐4(1H)‐one, are synthesized in one step from the corresponding 1‐substuituted or 1,3‐disubstituted 2‐pyrazolin‐5‐ones and 3‐chloroquinoxaline‐2‐carbonyl chloride using calcium hydroxide in boiling 1,4‐dioxane. The parent system carrying no substituent in positions 1 and 3 is obtained upon treatment of the 1‐PMB (p‐methoxybenzyl) protected congener with trifluoroacetic acid. Detailed NMR spectroscopic investigations including unambiguous chemical shift assignments of all 1H, 13C, and 15N resonances of the obtained tetracycles are reported.
Synthesis and physicochemical properties of new 1N o‐(m‐ and p‐) bromobenzyl substituted derivatives of 5‐(aminodialkyl)methylcytosine
Authors: Prukala Dorota
Published: March 2009

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Simple alkylation of 5‐(aminodialkyl)methylcytosine a‐d gives twelve new, potentially biologically active 1N o‐(m‐ or p‐) bromobenzyl derivatives of 5‐substituted cytosine 1‐12 with high regioselectivity. The structures of all compounds have been confirmed by elemental analysis, IR, 1H NMR and 13C NMR spectroscopic measurements.
Oxidation of N‐heterocyclics: A green approach
Authors: Sivasubramanian Ganarajan , Parameswaran Veembil Ramachandran
Published: March 2009

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Environmentally benign oxidation methods satisfy the postulates of green chemistry. Heterocyclic Noxides have applications in synthetic organic chemistry, chemotherapy and agrochemicals. Synthesis of Noxides using green oxidants will be attractive over the conventional methods. The presence of the N‐oxide group in the azine ring makes it more subject to electrophilic and nucleophilic attack and substantially expands the synthetic approaches for the modification of nitrogen‐containing heterocyclics. That is the reason for the increasing interest in the chemistry of heterocyclic N‐oxides. Some reactions adopted for oxidation of N‐heterocyclics have been discussed. Stereochemical and spectroscopic aspects have been mentioned. It will be advantageous if anchored catalysts are employed for industrial exploitation. Several physiochemical aspects of various methods have been discussed.
Synthesis, oxidation and dehydrogenation of cyclicN,O‐ andN,S‐acetals. Part III. Transformation ofN,O‐acetals: 3‐acyl‐1,3,4‐oxadiazolines
Authors: Somogyi László
Published: March 2009

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Various aldehyde and ketone acylhydrazones are synthesized and, under acylating conditions, cyclized into 3‐acyl‐1,3,4‐oxadiazolines. The scope and limitations of these cyclizations and the possible side reactions (e.g. formation of the open‐chainN,O‐acylhydrazinocarbinols) are dissected. For the first time, simple, convenient and efficient dehydrogenations of 3‐acyl‐1,3,4‐oxadiazolines to oxadiazoles by treatment with potassium permanganate, or more conveniently, with ammonium cerium(IV) nitrate (CAN) are presented. CAN oxidation of 2,2‐disubstituted 3‐acyl‐1,3,4‐oxadiazolines, as well as that of aldehyde diacylhydrazones (open‐chain isomers of 2,5‐disubstituted 3‐acyl‐1,3,4‐oxadiazolines) regenerates the parent carbonyl compounds.
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

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A 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

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Two 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

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Trifluoroacetolysis 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

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The 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

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The 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

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The 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

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The 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

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N‐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

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Novel 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

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This 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

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3‐(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

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A 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

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The 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

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Quinazoline‐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

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Iodine 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

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An 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

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Disubstituted 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

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N‐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

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An 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

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The 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

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Five 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

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An 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

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Treatment 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

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Reacting 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

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Concise 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

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Nucleophilic 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

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A 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

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A 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

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The 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

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Some 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

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A 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

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The 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

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This 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

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Reaction 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.