bluuebunny/crossref_metadata_2025_split huggingface dataset:
Free‐radical 4‐nitrophenylation of thieno[2,3‐b]pyridine. Part 3: Consideration of mechanistic and selectivity factors involved in the substitution process
Authors: Klemm Leroy H. , Reed Scott M. 
Published: March 2009

AbstractA 1:1 geometrically oriented encounter complex between thieno[2,3‐b]pyridine (1) and 4‐nitrophenyldia‐zoacetate (2) is proposed to account for the dominant formation (ca. 64%) of the 2‐isomer in the mixture of 4‐nitrophenyl‐l isomers obtained previously. A mechanism involving one‐electron transfer from 1 to 2 plus fragmentation of 2· into 4‐nitrophenyl free radical, N2, and acetate ion is invoked. Formation of other isomers is discussed.It is noted that there is a close correlation between orientational rules plus mechanisms of reaction for numerous free‐radical substitutions (SR) with SN reactions of alkyllithiums on furan, thiophene, N‐alkylpyrroles, pyridine, and their condensed aromatic molecules, including 1, as substrates. Also isomeric selectivities for SE, SN, and SR substitutions into 1 were shown to be qualitatively consistent with one another. While SE reactions occur largely at position 3 and then at 2, SN and SR reactions occur either at 2 or 6. Selectivity for positions 4 or 5 is small or zero.
Synthesis of diazadibenzo‐18‐crown‐6 ligands with appended chromophoric and fluorophoric groups as potential metal ion chemosensors
Authors: Xue Guo‐Ping , Savage Paul B. , Krakowiak Krzysztof E. , Izatt Reed M. , Bradshaw Jerald S. 
Published: March 2009

AbstractSix new diazadibenzo‐18‐crown‐6 ligands substituted with two each of 8‐hydroxyquinoline (7), 8‐amino‐quinoline (attached through its C‐2 or C‐7 position) (12 and 13), 8‐methoxyquinoline (18), 5‐chloro‐8‐methoxyquinoline (19), and dansylamidoethyl (21) side arms were synthesized as potential metal ion chemosensors and potential reagents for the selective extraction of certain metal ions from aqueous solutions. Ligands 7, 12, 13, 18, and 19 were synthesized by reductive amination of diazadibenzo‐18‐crown‐6 (5) and the appropriate quinolinecarboxaldehydes. Bis(dansylamidoethyl)‐substituted ligand 21 was synthesized by treating diazacrown ether 5 with N‐dansylaziridine (20).
Synthesis of some isomeric quinoxaline derivatives with 6‐azauracil cycle
Authors: Wiedermannová Iveta , Slouka Jan 
Published: March 2009

AbstractBy diazotization of 3‐(2‐aminophenyl)‐1,2‐dihydroquinoxaline 1c, its 3‐(4‐aminophenyl)‐isomer2c, 3‐(2‐aminobenzyl)‐1,2‐dihydroquinoxaline‐2‐one 3c and its 3‐(4‐aminobenzyl)‐isomer 4c and by azo coupling of formed diazonium salts with ethyl cyanoacetylcarbamate, corresponding hydrazones ld‐4d were prepared. Cyclization of these compounds afforded compounds containing two heterocyclic rings with acidic N‐H groups in their molecules: 3‐[2‐(5‐cyano‐6‐azauracil‐1‐yl)‐phenyl]‐1,2‐dihydroquinoxaline‐2‐one 1e, its 4‐isomer 2e, 3‐[2‐(5‐cyano‐6‐azauracil‐1‐yl)‐benzyl]‐1,2‐dihydroquinoxaline‐2‐one 3e and its 4‐isomer 4e. The aminoderivative 1c was prepared by the reaction of N‐acetylisatine with o‐phenylenediamine and by hydrolysis of prepared N‐acetylderivative 1a. The aminoderivative 2c was prepared by the condensation of 4‐acetylaminophenylglyoxylic acid with o‐phenylenediamine and by hydrolysis of prepared N‐acetylderivative 2a. The aminoderivative 3c was prepared by the condensation of 2‐nitrophenylpyruvic acid with o‐phenylenediamine and by the reduction of the formed nitroderivative 3b and finally starting aminoderivative 4c was obtained by the condensation of o‐phenylenediamine with 4‐aminophenylpyruvic acid.
Synthesis and chemical reactivity of 3‐oxo‐2‐arylhydrazono‐propanenitriles
Authors: Abdallah Sanaa O. , Metwally Nadia H. , Anwar Hany F. , Elnagdi Mohamed H. 
Published: March 2009

Abstract2‐Formyl‐2‐arylhydrazonoethanenitriles 6b‐d where prepared via reacting enaminonitrile 2b,c with aromatic diazonium salts. These reacted with phenylhydrazine to yield bis hydrazones that were converted to arylazopyr‐azoles via a novel Vilsmeier‐Haack reaction type. Reaction of 6c with hydroxylamine afforded oxime that could be successfully cyclised into arylazoisoxazole. Reaction of 6c with hydrazine hydrate to yield arylazoamino‐pyrazole that proved to be excellent precursors for synthesis functional substituted pyrazolopyrimidines.
Preparation of 1,3‐selenazoles using selenazadienes
Authors: Koketsu Mamoru , Imagawa Michie , Mio Takumi , Ishihara Hideharu 
Published: March 2009

AbstractReactions of selenazadienes with chloroacetonitrile yielded 1,3‐selenazol‐5‐carbonitriles in moderate to high yields. Reactions of the selenazadienes with chloroacetyl chloride and then with amines gave 1,3‐sele‐nazole‐5‐carboxamides.
Synthesis of 32‐phenyl‐substituted methyl E/Z‐pyropheophorbide‐a's from methyl E/Z‐pyropehophorbide‐a 131‐ketoximes
Authors: Wang Jin‐Jun , Imafuku Kimiaki , Shim Yong Key , Jiang Gui‐Ji 
Published: March 2009

AbstractMethyl E/Z‐pyropheophorbide‐a 131‐ketoximes 2a,b and their O‐acetyl derivatives 3a,b were oxidized with osmium(VIII) oxide to give aldehydes 4a,b and 5a,b, respectively. The Wittig reactions of the aldehyde chlorines 4a,b and 5a,b with benzyltriphenylphosphonium chloride were performed to form the corresponding methyl (31E/Z,131E/Z)‐32‐phenylpyropheophorbide‐a 131‐ketoximes 6aa‐bb and their O‐acetyl derivatives 7aa‐bb; hydrolysis of these ketoximes 6aa,ba and 6ab,bb in formic acid produced methyl (E/Z)‐32‐phenylpyropheophorbide‐a's 8a,b.
Selective nucleophilic replacement of the benzylsulfanyl group in 2,4‐disulfanyl‐substituted thieno[2,3‐d]pyrimidin‐6‐carboxylic acid derivatives by secondary amines
Authors: Briel Detlef , Drescher Simon , Dobner Bodo 
Published: March 2009

AbstractThieno[2,3‐d]pyrimidines with benzylsulfanyl and allylsulfanyl group in the presence of other alkylsul‐fanyl substituents react selectively under mild conditions with secondary amines under replacement of the benzyl or allyl residue whereas the other substituents remain intact. This enables the synthesis of different basic substituted derivatives with potentially biologically activity.
Multinuclear NMR studies and ab initio structure calculations of hindered phencyclone diels‐alder adducts from symmetrical cyclic dienophiles: Cyclohexene, vinylene carbonate, vinylene trithiocarbonate and two N‐aryl maleimides
Authors: Callahan Ronald , Ramirez Orlando , Rosmarion Kerstin , Rothchild Robert , Bynum Kevin C. 
Published: March 2009

AbstractA series of hindered Diels‐Alder adducts have been prepared from phencyclone, 1, with various unusual symmetrical cyclic dienophiles, including cyclohexene, 2a; vinylene carbonate, 2b; vinylene trithiocarbonate, 2c; and the N‐aryl maleimides: N‐(4‐dimethylamino‐3,5‐dinitrophenyl)maleimide (“Tuppy's maleimide”), 2d; and N‐[3,5‐bis(trifluoromethyl)phenyl]maleimide, 2e. The highly hindered adducts, 3a‐e, respectively, were extensively characterized by one‐ and two‐dimensional NMR methods, observing proton, carbon‐13 and fluorine‐19. High resolution COSY45 spectra permitted rigorous proton NMR assignments. The 2D heteronuclear C‐H chemical shift correlation spectra (HETCOR, XHCORR) were obtained for adducts 3a‐d, allowing specific assignments for protonated carbons. Corrections to earlier proton NMR assignments for the vinylene carbonate adduct are given; results of the gated decoupling 13C NMR experiment for this adduct supported endo adduct stereochemistry. Relative proton chemical shifts for bridgehead phenyls of adduct 3c appeared anomalous relative to other adducts, suggesting possible special anisotropic interactions (with endocyclic sulfur or other anisotropic groups in the product) due to the unusual calculated orientation of the phenyls. The unsubstituted bridgehead phenyls in all adducts were shown to exhibit slow exchange limit (SEL) 1H and 13C spectra on the NMR timescales at ambient temperatures (7 tesla) showing slow rotations about the C(sp3)‐C(aryl sp2) bonds. The rapid rotation of the N‐aryl rings of the maleimide adducts was indicated by fast exchange limit spectra, suggesting that ortho substitution of the N‐aryl ring may be necessary to slow this rotation to the SEL regime. Ab initio geometry optimizations at the Hartree‐Fock level were carried out for each adduct, with the 6‐31G* basis sets. Appreciable geometry differences were seen in calculated structures, and significant NMR chemical shift differences were experimentally observed, depending on the nature of the groups attached to the (Z)‐HC=CH moiety of the dienophiles.
Synthesis of new substituted 5‐methyl‐3,5‐diphenylimidazolidine‐2,4‐diones from substituted 1‐(1‐cyanoethyl‐1‐phenyl)‐3‐phenylureas
Authors: Sedlák Miloš , Keder Roman , Hanusek Jiří , Růzička Aleš 
Published: March 2009

AbstractThe reaction of substituted phenyl isocyanates with 2‐amino‐2‐phenylpropanenitrile and 2‐amino‐2‐(4‐nitrophenyl)propanenitrile has been used to prepare substituted 1‐(1‐cyanoethyl‐1‐phenyl)‐3‐phenylureas. In anhydrous phosphoric acid the first products to be formed from 1‐(1‐cyanoethyl‐1‐phenyl)‐3‐phenylureas are phosphates of 4‐methyl‐4‐phenyl‐2‐phenylimino‐5‐imino‐4,5‐dihydro‐1,3‐oxazoles, which on subsequent hydrolysis give the respective ureidocarboxylic acids. On prolongation of the reaction time, the phosphates of 4‐methyl‐4‐phenyl‐2‐phenylimino‐5‐imino‐4,5‐dihydro‐1,3‐oxazoles rearrange to give phosphates of 5‐methyl‐4‐imino‐3,5‐diphenylimidazolidin‐2‐ones, and these are subsequently hydrolysed to the respective substituted 5‐methyl‐3,5‐diphenylimidazolidin‐2,4‐diones. The ureidocarboxylic acids were also prepared by alkaline hydrolysis of 5‐methyl‐3,5‐diphenylimidazolidin‐2,4‐diones. The 5‐methyl‐3,5‐diphenylimidazolidin‐2,4‐diones and ureidocarboxylic acids were characterised by their 1H and 13C NMR spectra. Structure of the 5‐methyl‐5‐(4‐nitrophenyl)‐3‐phenylimidazolidine‐2,4‐dione was verified by X‐ray diffraction. The alkaline hydrolysis of individual imidazolidine‐2,4‐diones was studies spectrophoto‐metrically in sodium hydroxide solutions at 25 °C. The rate‐limiting step of the base catalysed hydrolysis consists in decomposition of the tetrahedral intermediate. The reaction is faster if electron‐acceptor sub‐stituents are present in the 3‐phenyl group of imidazolidine‐2,4‐dione cycle. The pKa values of individual 5‐methyl‐3,5‐diphenylimidazolidine‐2,4‐diones have been determined kinetically.
Reaction of β‐cyano esters with hydrazine hydrate. Unexpected formation of dipyrrolo[1,2‐b:1′,2′‐e][1,2,4,5]tetrazine, a novel ring system
Authors: Wejroch Krystyna , Lange Jerzy , Wesołowska Aneta , Ski Tadeusz Jagodzi , Sadowska Maja , Karolak‐Wojciechowska Janina 
Published: March 2009

AbstractSome intermediates and by‐products of the title reaction, known to yield 6‐hydrazinopyridazine‐3‐one derivatives, were isolated or detected when the amount of hydrazine hydrate used to react with two model β‐cyano esters was reduced to less than two equivalents. N'‐(1‐amino‐4‐hydrazino‐4‐oxo‐2‐phenylbutyli‐dene)‐4‐hydrazino‐4‐oxo‐2‐phenylbutanehydrazonamide and 3,3,8,8‐tetramethyl‐2,3,7,8‐tetrahydro‐1H,6H‐dipyrrolo[1,2‐b:1′,2′‐e][1,2,4,5]tetrazine‐1,6‐dione were isolated as the terminal products of side‐reactions; they were unreactive to hydrazine. The latter compound is a derivative of a novel ring system. Mechanism of the reaction was proposed.
Synthesis of meso‐tetra acid and ester functionalized calix[4]pyrroles
Authors: Akar Ahmet , Aydogan Abdullah 
Published: March 2009

AbstractNovel meso‐tetracarboxylic acid and meso‐tetraester functionalized calix[4]pyrroles were synthesized by condensation of pyrrole with levulinic acid and ethyl pyruvate in sufficient yields. In addition, mixed condensation products can also be synthesized using this method. These new compounds may be useful as molecular receptors and polyfunctional starting materials for further derivatization.
Synthesis, characterization and biological activity of some 1,2,4‐triazine derivatives
Authors: El‐Barbary A. A. , Sakran M. A. , El‐Madani A. M. , Nielsen Claus 
Published: March 2009

Abstract4‐Amino‐6‐methyl‐3‐(2H)‐thioxo‐5‐(4H)‐oxo‐1,2,4‐triazine (1) was condensed with 2‐methyl (or phenyl)‐4H‐3,1‐benzoxazin‐4‐one (5a,b) in boiling acetic acid to give compounds 8‐11. Reacting 1 with chloroacetyl chloride afforded the corresponding chloroacetamido and triazinothiadiazine derivatives 12 and 13. Condensing 2 with succinic anhydride and/or phthalic anhydride yielded compounds 14 and 15. Benzoylation of 4‐amino‐6‐methyl‐3‐(2H)‐thioxo‐5‐(4H)‐oxo‐2‐(2,3,4,5‐tetra‐O‐acetyl‐α‐D‐glucopyra‐nosyl)‐1,2,4‐triazine (19) afforded the corresponding 4‐N,N‐dibenzoyl derivative 20. Deblocking of the N‐2 glycoside 21 and the S‐glycoside 22 by methanolic ammonia gave compounds 23 and 24. Acetylation of 4‐amino glycoside 25a afforded the corresponding 4‐mono‐ and 4‐diacetyl derivatives 26 and 27. Deamination of 25a,b yielded compounds 28a,b. Methylation of compound 28b afforded the corresponding N4‐ and S‐methyl derivatives 29 and 30.
Synthesis of 2‐amino‐4,5‐dihydro‐3‐methanesulfonylfurans (and ‐thiophenes)
Authors: Yamagata Kenji , Okabe Fumi , Maruoka Hiroshi , Tagawa Yoshinobu 
Published: March 2009

Abstract2‐Amino‐4,5‐dihydro‐3‐methanesulfonylfurans 7 and 2‐amino‐4,5‐dihydro‐3‐methanesulfonylthiophenes 8 were prepared by deamidation of tetrahydro‐2‐imino‐3‐methanesulfonyl‐3‐furancarboxamides 3 and of tetrahydro‐2‐imino‐3‐methanesulfonyl‐3‐thiophenecarboxamides 4 with bases. Compounds 3 and 4 were obtained by reaction of 2‐amino‐4,5‐dihydro‐3‐furancarboxamides 1 and 2‐amino‐4,5‐dihydro‐3‐thio‐phenecarboxamides 2 with methanesulfonyl chloride in the presence of triethylamine.
A facile one‐pot synthesis of novel substituted 1,2,3,4‐tetrahydropyrimidines Part 5 : Synthesis of bis[(l‐alkyl/aralkyl)‐5‐benzoyl‐6‐methylthio‐1,2,3,4‐tetrahydropyrimidinyl]alkane and benzene, bis[3‐phenyl‐7‐methyl‐4,5,6,7‐tetrahydropyrazolo[3,4‐d]‐pyrimidinyl]alkane and bis[1‐benzyl‐7‐phenyl‐1,2,3,4‐tetrahydro‐pyrazolo[1,5‐a]triazinyl]alkane and benzene
Authors: Dutta Milan Ch. , Chanda Kaushik , Vishwakarma Jai N. , Helissey Philippe 
Published: March 2009

AbstractBis‐1,2,3,4‐tetrahydropyrimidinylalkanes/benzenes 2a‐f have been synthesized by the reaction of N,S‐acetals with formaldehyde and diamines. Reaction of pyrazoles 3a and 3b with diamines and formaldehyde yield bis‐4,5,6,7‐tetrahydropyrazolo[3,4‐d]pyrimidinylalkanes 4a‐b and bis‐1,2,3,4‐tetrahydropyrazolo[1,5‐a]triazinylalkanes and benzene 5a‐c respectively in good yields.
Synthesis, characterization and spectral studies of various newer 4‐benzyloxy‐1H‐indole‐2‐carboxylic acid (arylidene)‐hydrazides
Authors: Jain Asheesh Kumar , Gupta Pradeep Kumar , Ganesan Kumaran , Pande Ambuja , Pardasani Deepak , Malhotra Ramesh Chandra 
Published: March 2009

Abstract4‐Benzyloxyindole‐2‐carboxylic acid hydrazide reacts with aromatic and heterocyclic aldehydes in alcoholic medium in refluxing conditions to give 4‐benzyloxy‐1H‐indole‐2‐carboxylic acid (arylidene)‐hydrazides, important synthetic intermediates for the synthesis of a newer class of pharmacologically active compounds. We describe here the synthesis of various 4‐benzyloxy‐1H‐indole‐2‐carboxylic acid (arylidene)‐hydrazides by conventional as well as microwave irradiation techniques. The structures of these compounds have been confirmed by spectroscopic techniques (FTIR, NMR and MS). Some of the interesting features of the electron impact mass spectral fragmentation pattern of these compounds are also discussed.
Reaction of 1,3‐dicarbonyl compounds with o‐phenylenediamine or 3,3′‐diaminobenzidine in water or under solvent‐free conditions via microwave irradiation
Authors: Wang Zhong‐Xia , Qin Hua‐Li 
Published: March 2009

AbstractReaction of ophenylenediamine with β‐diketones or β‐ketoesters in water formed 2‐substituted benzimi‐dazoles. Reaction of 3,3′‐diaminobenzidine gave similar results. Under microwave irradiation conditions solvent‐free reaction of o‐phenylenediamine with β‐ketoesters afforded l,5‐benzodiazepin‐2‐one derivatives. An exception is the reaction of o‐phenylenediamine with ethyl acetoacetate under microwave irradiation, which gave 2‐methylbenzimidazole.
A microwave induced cyclisation of α‐phenylsulfonyl‐enaminoacrylates for the preparation of 4‐aryl‐4H‐1,4‐benzothiazine 1,1‐dioxide derivatives
Authors: López Simón E. , Salazar José , Rebollo Oscar , Restrepo Jelem 
Published: March 2009

AbstractSeveral 4‐aryl‐4H‐1,4‐benzothiazine 1,1‐dioxide derivatives have been prepared in good yields by microwave promoted cyclisation of α‐phenylsulfonyl‐enaminoacrylate intermediates in basic media. Benzothiazines were obtained without the use of a catalyst in short reaction times.
Syntheses ofN‐[3‐(1‐methyl‐1H‐2‐imidazolyl)propyl]benzamides andN‐[3‐(1‐methyl‐1H‐2‐imidazolyl)propyl]benzenesulfonamides
Authors: Shafiee A. , Shabani P. , Vosooghi M. , Foroumadi A. 
Published: March 2009

AbstractA series of substitutedN‐(4‐substituted‐benzoyl)‐N‐[3‐(1‐methyl‐1H‐imidazol‐2‐yl)propyl]amines (13) andN‐arylsulfonyl‐N‐[3‐(1‐methyl‐1H‐imidazol‐2‐yl)propyl]amines (14) were prepared from the reaction of 3‐(1‐methyl‐1H‐imidazol‐2‐yl)propan‐1‐amine (7) with substituted benzoyl chloride or substituted‐benzene sulfonyl chloride respectively. Compound7was prepared by two independent methods.
A rapid and efficient method for the reduction of quinoxalines
Authors: McKinney Andrew M. , Jackson Kevin R. , Salvatore Ralph Nicholas , Savrides Elena‐Maria , Edattel Mary Jane , Gavin Terrence 
Published: March 2009

AbstractMono and di‐substituted alkyl and aryl quinoxalines are rapidly reduced in high yield to their respective 1,2,3,4‐tetrahydro‐derivatives by borane in THF solution. In the case of the 2,3‐di‐substituted compounds, reduction is stereoselective yielding exclusively the cis‐isomers. Sodium borohydride in acetic acid also reduces alkyl and aryl quinoxalines, but proceeds with lower yields and often produces side products. Sodium borohydride in ethanol reduces quinoxaline and 2‐methylquinoxaline in high yield; however, the reaction is very slow, whereas 2,3‐dialkyl and 2‐aryl quinoxalines are not efficiently reduced by sodium borohydride in ethanol.
New data about the reaction of benzyolacetonitrile with malononitrile and its self‐condensation
Authors: Abdelrazek Fathy M. , Michael Farid A. 
Published: March 2009

Abstractmagnified imageThe reactions of benzoylacetonitrile with malononitrile in refluxing pyridine and its self condensation under fusion conditions in the presence of ammonium acetate and in refluxing pyridine were reinvestigated. New data were found and plausible mechanisms to account for the formation of the products are suggested.
Aziridines as templates: A general strategy for the stereospecific synthesis of 2‐azetidinones
Authors: Sharma S. D. , Kanwar Seema , Rajpoot Shivani 
Published: March 2009

Abstractmagnified imageVarious routes to a variety of azridine‐2‐carboxylates have been described and the stereochemistry of these compounds has been determined by spectroscopic methods. Further, greater diversity of β‐lactams via ring expansion of these azridines‐2‐carboxylates were obtained by a general, efficient and direct stereospecific approach.
Cycloaddition reaction of schiff bases with ketenes generated by pyrolysis of 2‐aryl‐substituted 1,5,7‐trioxaspiro[2.5]octane‐4,8‐diones
Authors: Tsuno Takashi , Kondo Kosuke , Sugiyama Kunio 
Published: March 2009

Abstractmagnified imageThe α‐oxo ketenes 6 which are generated by the pyrolysis of the 2‐aryl‐substituted 1,5,7‐trioxaspiro[2.5]octane‐4,8‐diones 1, were reacted with Schiff bases 2 to give spiro compounds constructed between the β‐lactam and 1,3‐dioxolan‐4‐one; i.e., the 2,3,6‐triaryl‐2‐aza‐5,7‐dioxaspiro[3.4]octane‐1,8‐diones 3 and 4. Hydrogenation of the mixture of 3a and 4a in the presence of catalytic amount of Pd‐C produced the trans‐2‐benzyloxy‐1,4‐diphenyl‐β‐lactam‐3‐carboxylic acid 9.
Amination of pyrido[3,2,1‐jk]carbazol‐6‐ones
Authors: Dang Hoai V. , Stadlbauer Wolfgang 
Published: March 2009

Abstractmagnified imageAmination of 4‐hydroxypyridocarbazolones 1 with aniline or benzylamine gave in good yields 4‐amines 3. With piperidine in a sealed tube from 4‐hydroxy‐ or 4‐chloro‐5‐alkylpyridocarbazolones 1 or 4 ring opened 1‐acylcarbazoles 5 were obtained. Only 4‐hydroxy‐5‐phenyl‐pyridocarbazolone 1d gave 4‐amines 6. Reduction of 4‐azidopyridocarbazolones 7 either by catalytic hydrogenation or in a 2‐step synthesis via phosphazenes 8 gave 4‐aminopyridocarbazolones 9. Amines 9 were also obtained from benzylamines 3 by catalytic debenzylation. A one step amination of 4‐hydroxy‐5‐phenylpyridocarbazolone 1d via debenzylation to 9d was observed by reaction with benzylammonium chloride. At elevated temperatures the highly fused 6,13b‐diazaindeno[1,2,3‐hi]chrysenone 10 was formed from 1d.
A facile KF/Al2O3 mediated method for the synthesis of substituted 3‐arylchromene‐2‐thiones
Authors: Xu Xiaowei , Hu Yongzhou 
Published: March 2009

Abstractmagnified imageA convenient and efficient method for the preparation of 3‐aryl‐chromene‐2‐thiones was reported. These compounds 2a‐2o with various functional groups were synthesized in high yield by a KF/Al2O3 meditated reaction of deoxybenzoins with CS2 under mild conditions.
Synthesis of novel 2‐aminoimidazo[4,5‐b]pyridines, including the thieno analogue of the cooked‐food mutagen IFP
Authors: Björk Malin , Grivas Spiros 
Published: March 2009

Abstractmagnified imageEight new compounds, including three new ring systems obtained via the Friedländer condensation of ortho‐aminothiophenecarbaldehydes 11, 21 and 24 with creatinine (8), are reported. The condensation afforded 1, which is the thieno analogue of the cooked‐food mutagen IFP (2‐amino‐1,6‐dimethylfuro[2,3‐e]imidazo[4,5‐b]pyridine), and the benzothieno[2,3‐e]‐ and benzothieno[3,2‐e]imidazo[4,5‐b]pyridines 2 and 3. Attempts to condense 11 with isocreatinine (12) were unsuccesful. Desulfurization of 3 gave the known cooked‐food carcinogen PhIP. The 2‐nitro (4) and 2‐hydroxy (5) derivatives of 3 are reported. The related 2‐amino‐1‐methyl‐imidazo[4,5‐b]benzothiophene (25) was synthesized by a different route. Fully assigned 1H and 13C nmr data of all new compounds are reported.
Synthesis of 1‐substituted 3,5‐diaryl‐2‐pyrazolines by the reaction of α,β‐unsaturated ketones with hydrazines
Authors: Lévai Albert , Jekö József 
Published: March 2009

Abstractmagnified image1‐Acetyl‐, 1‐propionyl‐ and 1‐phenyl‐3,5‐diaryl‐2‐pyrazolines have been synthesized by the reaction of the appropriate α,β‐unsaturated ketones with hydrazine or phenylhydrazine in hot acetic acid or propionic acid. Structures of all new 2‐pyrazolines 16‐40 have been elucidated by microanalyses, 1H and 13C nmr spectroscopies.
The synthesis of substituted phenylpyrimidines via suzuki coupling reactions
Authors: Delia Thomas J. , Schomaker Jennifer M. , Kalinda Alvin S. 
Published: March 2009

Abstractmagnified imageThis paper describes the mon‐, di‐, and triarylation of the pyrimidine ring. It is possible to introduce one or more aryl rings in generally good yields and in a specific order, namely first in position 4, second in position 6, followed by position 2. A study of solvent and catalyst requirements has also been conducted.
Synthesis of some new spiro naphtho[2,3‐d][1,3]dithiole‐4,9‐dione derivatives
Authors: El‐Shafie A. K. , Soliman A. M. , Sultan A. A. , Abd‐Alla E. 
Published: March 2009

Abstractmagnified image2(1‐Acetyl‐2‐oxopropylidene)naphtho[2,3‐d][1,3]dithiole‐4,9‐dione 1 reacts with a variety of bidentates reagents to give some new functionally substituted spiro naphthodithiole‐4,9‐dione derivatives.