bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proton‐ionizable crown compounds. 9. Synthesis and structural studies of new 14‐crown‐4 compounds containing a pyridine or 4‐pyridone subcyclic unit
Authors: Bradshaw Jerald S. , Guynn John M. , Wood Steven G. , Wilson Bruce E. , Kent Dalley N. , Izatt Reed M. 
Published: April 2009

AbstractFour new 14‐crown‐4 macrocyclic ligands containing either a pyridine or a 4‐pyridone subcyclic unit have been prepared. Two of the 4‐pyridono‐crowns contained lipophilic hydrocarbon substituents. The starting octyl‐ and benzyl‐substituted 4‐oxa‐1,7‐heptanediols were prepared from the 2‐octyl‐ or 2‐benzyl‐1,3‐propane‐diol. When the two substituted 4‐oxa‐1,7‐heptanediols were treated with tosyl chloride, both the expected 2‐substituted‐4‐oxaheptane‐1,7‐ditosylates and the ditosylate of the dimeric diol were isolated. X‐ray structure determinations were carried out on two of the new 14‐crown‐4 compounds.
Selected reactions on the o‐aminonitrile system of substituted pyrroles
Authors: Eger Kurt , Pfahl Johannes Georg , Folkers Gerd , Roth Hermann J. 
Published: April 2009

AbstractThe synthesis of the difficult to obtain pyrrolo[2,3‐d]pyrimidine‐2,4‐diamine (4) is reported. Furthermore, some unexpected reactions on the 2‐aminopyrrole‐3‐carbonitrile system are described 15‐17.
The oxidation of 6‐ and 7‐aryl‐4(3h)‐pteridinones by immobilized arthrobacter M‐4 cells containing xanthine oxidase
Authors: De Meester Johan W. G. , Van Der Plas Henk C. , Middelhoven Wouter J. 
Published: April 2009

AbstractThe preparation of 6‐ and 7‐(pX‐phenyl)‐4(3H)‐pteridinones (X = H, CH3, OCH3) is described. The oxidation of these compounds by (immobilized) Arthrobacter M‐4 cells containing xanthine oxidase has been studied. The oxidation monitored by uv spectroscopy usually goes fast, except for 7‐(pX‐phenyl)‐4(3H)‐pteridinones (X = CH3, OCH3), which are slowly oxidized. With bacterial cells immobilized in gelatine crosslinked with glutaraldehyde small laboratory‐scale oxidations were carried out. Based on spectral data the products of the oxidation reactions are 6‐ and 7‐aryllumazines.
Crystal structure and tautomerism in 4‐phenylisoxazoles with two potential hydroxyl groups at positions 3 and 5
Authors: Zvilichovsky Gury 
Published: April 2009

AbstractThe crystal structure of 4‐phenyl‐3‐hydroxyisoxazol‐5‐one semihydrate exhibits an exceptional hydrogen bonded polymeric structure with a unit cell of 8 molecules. The hydrogen bonds stretch out, using the oxohydroxy groups in positions 3 and 5 in the direction of one axis and along a perpendicular direction the layers are stitched together by water molecules. The layers are stitched by using four hydrogen bridges of water molecules, the heterocyclic ring nitrogen as well as the oxygen at position 5. Tautomerism of this moiety in solution is discussed, in light of some new dialkylation products. The state in which these products exist in solution depends on the solvent. A zwitterionic tautomer is present in ether. In some alkylation conditions, the predominant dialkylation product is the N,N‐disubstituted betaine (Anhydro‐2,2‐dialkyl‐3(5)‐oxo‐5(3)hydroxy‐4‐phenylisoxazolonium hydroxide). Study of tautomerism in polar and protic solvent is unreliable owing to associations and dissociation phenomena.
2,3,4,9‐Tetrahydro‐1H‐pyrido[3,4‐b]indoles. II. Reversible transformation of 1‐alkyl‐2‐(4,9‐dihydro‐3H‐pyrido[3,4‐b]indol‐1‐yl)cyclohexanol into 1‐alkylidene‐2,3,4,9‐tetrahydro‐1H‐pyrido[3,4‐b]indoles
Authors: Bobowski George 
Published: April 2009

AbstractTreatment of 2‐(4,9‐dihydro‐3H‐pyrido[3,4‐b]indol‐1‐yl)‐1‐methylcyclohexanol (2a) with acetic anhydride or methyl isocyanate gave 2‐acetyl‐2,3,4,9‐tetrahydro‐1‐(6‐oxoheptylidene)‐1H‐pyrido[3,4‐b]indole (3) or 1,3,4,9‐tetrahydro‐N‐methyl‐1‐(6‐oxoheptylidene)‐2H‐pyrido[3,4‐b]indole‐2‐carboxamide (4), respectively. Simpler analogues, 1‐alkyl‐4,9‐dihydro‐3H‐pyrido[3,4‐b]indoles, 7, subjected to identical reaction conditions, gave 2‐acetyl‐1‐alkylidene‐2,3,4,9‐tetrahydro‐1H‐pyrido[3,4‐b]indoles8 and 1,3,4,9‐tetrahydro‐N‐methyl‐1‐alkyli‐dene‐2H‐pyrido[3,4‐b]indole‐2‐carboxamides 9, respectively. A limited lanthanide shift reagent study to determine stereochemical assignments was also performed.
Synthesis of methyl derivatives of 8‐desmethylxanthyletine and 8‐desmethylseseline, potential antiproliferative agents
Authors: Rodighiero P. , Manzini P. , Pastorini G. , Bordin F. , Guiotto A. 
Published: April 2009

AbstractA number of new methyl derivatives of pyranocoumarins, related to 8‐desmethylxanthyletine and to 8‐desmethylseseline, were synthesized. The syntheses were performed by cyclization in boiling N,N‐diethyl aniline of the propargyl or methylpropargyl ethers of the appropriate methyl derivatives of 7‐hydroxycou‐marin. Methyl groups have been introduced into positions which look most promising for enhancement of the photoreactivity of the compounds towards DNA.
Observations sur l'hydrolyse d'acétals dihydropyranniques
Authors: Thuy Vu Moc , Maitte Pierre 
Published: April 2009

AbstractL'hydrolyse des acétals dihydropyranniques par l'acide sulfurique conduit à des cyclohexénones, mais l'emploi de p.toluène sulfonate de pyridinium permet d'isoler les δ‐cétoaldéhydes, qui ne se crotonisent pas dans ces conditions.
A novel acyclic addition of ketenes to oxazoles/oxazolines
Authors: Nyce P. , Puar M. S. , Gala D. , Jaret R. S. 
Published: April 2009

AbstractThe addition of n‐butyryl chloride (1) to 5‐phenyloxazole (6) or 4,5‐dihydro‐5‐methyl‐4‐[(4′‐methylphenyl)‐sulfonyl]oxazole (8) in the presence of triethylamine lead to 1‐(5′‐phenyloxazol‐2′‐yl)‐1‐buten‐1‐yl butanoate (7) and 1‐(5′‐methyl‐4′‐[4″‐methylphenylsulfonyl]4′,5′‐dihydrooxazol‐2′‐yl)‐1‐buten‐1‐yl butanoate (9), respectively.
Synthesis of thiabenzene oxides and azathiabenzene oxides
Authors: Tominaga Yoshinori , Hidaki Shozo , Matsuda Yoshiro 
Published: April 2009

AbstractFused thiabenzene oxide, 2‐methyl‐4‐methylthiobenzo[b]thieno[3,2‐c]thiapyran 2,5,5‐trioxide (2) was synthesized by the reaction of 2,3‐dihydro‐2‐bis(methylthio)methylene‐3‐oxobenzo[b]thiophene 1,1‐dioxide (1) with trimethyl sulfoxonium iodide in the presence of sodium hydride in tetahydrofuran. Similarly, fused azathiabenzene oxide, 2‐methyl‐4‐methylthiobenzo[b]thieno[2,3‐c][1,2]thiazine 2,5,5‐trioxide (3) was prepared from 1 and sulfoximine in good yield.
Synthèse d'analogues furanniques et nitro‐2 furanniques du diméthyl‐7,12 benzanthracène
Authors: Bilger Christine , Demerseman Pierre , Royer René 
Published: April 2009

AbstractOn décrit les voies d'accès aux formyl‐1 hydroxy‐2 méthyl‐9 anthracène et formyl‐1 hydroxy‐2 diméthyl‐9,10 anthracène. Ces deux aldéhydes ortho‐hydroxylés sont transformés en anthra[2,1‐b]furannes mono‐ou diméthylés, ainsi que les acides et esters correspondants, par condensation avec le bromoacétate d'éthyle. Ils donnent par ailleurs des nitro‐2 anthra[2,1‐b]furannes mono‐ou diméthylés par traitement au bromonitrométhane, suivi de chauffage dans le toluène en prèsence d'acide para‐toluène sulfonique.
Regioselectivity in dipolar cycloaddition reactions of N‐phenylcinnamonitrilimine
Authors: Hassaneen Hamdi M. , Farag Ahmed M. , Shawali Ahmad S. , Algharib Mohamed S. 
Published: April 2009

AbstractThe regioselectivity of the cycloadditions of α,β‐unsaturated nitrilimine derived from N‐phenylcinnamo‐hydrazidoyl chloride 2 to C = Se, C = S and C = C double bonds of the resonance stabilized selenocyanate and thiocyanate anions, enol tautomer of dibenzoylmethane and benzalacetophenone was investigated. The results indicate that the reactions studied are dipole‐LUMO‐dipolarophile‐HOMO controlled and that the larger orbital coefficient in the LUMO of N‐phenylcinnamonitrilimine is on the carbon atom bearing the styryl group. The structures of the cycloadducts were assigned and confirmed on the basis of their elemental analyses and spectra.
Regioselective syntheses of 2‐amino‐4,5‐dialkylthiophene‐3‐carboxylates and their conversion to 3,4‐dihydro‐4‐oxothieno[2,3‐d]pyrimidine‐2‐carboxylates
Authors: Madding Gary D. , Thompson Michael D. 
Published: April 2009

AbstractThe synthesis of 3,4‐dihydro‐4‐oxothieno[2,3‐d]pyrimidine‐2‐carboxylates via acid catalyzed reactions of various 2‐aminothiophene‐3‐carboxylates with activated nitriles is presented. The requisite thiophenes were prepared regioselectively by methods which represent improvements over previously published procedures.
Heterocycles. Part X. Synthesis of new pyrimidine systems
Authors: El‐Rayyes N. R. , Ramadan H. M. 
Published: April 2009

AbstractSelected aryl aldehydes I were reacted with 1‐benzosuberone to give the corresponding 2‐arylidene‐1‐ben‐zosuberones II. Condensation of these chalcones with urea and thiourea revealed the formation of the corresponding substituted pyrimidin‐2‐ones III, and pyrimidine‐2‐thiones IV respectively. The structure of all products was substantiated by chemical and spectral methods.
Pteridines, LXXXIV. Synthesis, reactivity and properties of 1,3‐dimethyllumazine‐6‐ and 7‐carboxaldehyde derivatives
Authors: Kang Yonghan , Soyka Rainer , Pfleiderer Wolfgang 
Published: April 2009

AbstractConvenient syntheses of 1,3‐dimethyllumazine‐6‐ (7) and ‐7‐carboxaldehyde (19) are described. The reactivity of the carboxaldehyde group has been investigated by oxidations, reductions and various carbonyl reactions forming a series of new derivatives. The newly synthesized compounds were characterized by elemental analysis, uv and 1H‐nmr spectra.
Reaction of ketenes with N,N‐disubstituted α‐aminomethyleneketones. XX. Synthesis of 2H‐pyrano[2,3‐f]quinazoline derivatives
Authors: Mosti Luisa , Menozzi Giulia , Schenone Pietro 
Published: April 2009

AbstractThe polar 1,4‐cycloaddition of dichloroketene to N,N‐disubstituted (E)‐6‐aminomethylene‐7,8‐dihydro‐(2‐methyl)(2‐phenyl)quinazolin‐5(6H)‐ones III, prepared in good yields from 7,8‐dihydro‐(2‐methyl)‐(2‐phenyl)quinazolin‐5(6H)‐ones via their 6‐hydroxymethylene derivatives I and II, gave in satisfactory to excellent yields N‐N‐disubstituted 4‐amino‐3,3‐dichloro‐3,4,5,6‐tetrahydro‐(8‐methyl)(8‐phenyl)‐2H‐pyrano‐ [2,3,‐f]quinazolin‐2‐ones IV, which are derivatives of the new heterocyclic system pyrano[2,3‐f]quinazoline. This cycloaddition occurred both in the case of aliphatic and aromatic N‐substitution only with 2‐phenyl‐enaminones III, whereas with 2‐methyl derivatives III the reaction took place only in the case of aromatic N‐monosubstitution.Dehydrochlorination of IV with DBN afforded, generally in excellent yields, N,N‐disubstituted 4‐amino‐3‐chloro‐5,6‐dihydro‐(8‐methyl)(8‐phenyl)‐2H‐pyrano[2,3‐y]quinazolin‐2‐ones, which were dehydrogenated with DDQ to give N,N‐disubstituted 4‐amino‐3‐chloro‐(8‐methyl)(8‐phenyl)‐2H‐pyrano[2,3‐f]quinazolin‐2‐ones in excellent yields.
Benzodioxines‐1,4 disubstituées en position 2,3 par des groupements pharmacophores
Authors: Coudert Gérard , Borredon‐Watrin Corinne , Guillaumet Gérald 
Published: April 2009

AbstractAfin d'obtenir des composés présentant à la fois des propriétés α et β adrénolytiques, nous avons préparé des benzodioxines‐1,4 disubstituées sur l'hétérocycle par des groupements susceptibles d'introduire les activités recherchées.
Synthetic Approaches to cularines. III. Nucleophilic addition and substitution
Authors: De Lera Angel Rodríguez , Sa á José M. , Suau Rafael , Castedo Luis 
Published: April 2009

AbstractAttempts to induce the formation of the dibenzoxepine ring of cularine compounds by generating an electron‐deficient system in ring C of an 8‐hydroxybenzylisoquinoline met with failure. Attack by C‐8 phenol on a “p‐quinone methide” intermediate afforded benzofurans 16, which it has been suggested are intermediates in the biogenesis of quettamines. Among the nucleophilic substitution reactions tried, only that based on a phenoxide attack on a benzyne intermediate (generated by dimsyl sodium treatment of a 2′‐bromo‐8‐hydroxybenzylisoquinoline) afforded the dibenzoxepine nucleus of tetradehydrocularines 25 and 27. Competing N‐attack afforded the indolizine skeleton present in 24 and 26. From compounds 25 and 27, the corresponding cularines, cularimines and oxocularines were obtained.
Asymmetrical porphyrins. I. Synthesis, characterization and physicochemical properties of phenyl/4‐benzyloxyphenyl 5,10,15,20‐substituted porphyrins
Authors: Datta‐Gupta N. , Malakar D. , Rice Lesa , Rivers Sheila 
Published: April 2009

AbstractA complete series of five phenyl/4‐benzyloxyphenyl 5,10,15,20‐substituted porphyrin has been synthesized, characterized by analysis, Rf values, and proton‐nmr spectroscopy (pmr). Their physicochemical properties, namely ir spectra, absorption spectra, emission spectra, excited state life‐times, pK3 values, reduction potentials, and kinetics of Cu(+2) insertion, have been determined. Attempts have been made to correlate these physicochemical properties with the structures of the porphyrins.
Reaction of sulfenes with heterocyclic N,N‐disubstituted α‐aminomethyleneketones. XIII. Synthesis of 1,2‐oxathiino[6,5‐f]quinazoline derivatives
Authors: Menozzi Giulia , Bargagna Alberto , Mosti Luisa , Schenone Pietro 
Published: April 2009

AbstractThe 1,4‐cycloaddition of sulfene to N,N‐disubstituted (E)‐6‐aminomethylene‐7,8‐dihydro‐(2‐methyl)‐(2‐phenyl)quinazolin‐5(6H)‐ones I gave N,N‐disubstituted 4‐amino‐3,4,5,6‐tetrahydro‐(8‐methyl) (8‐phenyl)‐1,2‐oxathiino[6,5‐f]quinazoline 2,2‐dioxides II, which are derivatives of the new heterocyclic system 1,2‐oxathiino[6,5‐f]quinazoline. With 2‐phenylenaminones Id‐h, the cycloaddition occurred, generally in satisfactory yields, both in the case of aliphatic N,N‐disubstitution and aromatic N‐monosubstitution, whereas with 2‐methyl enaminones Ia‐c the reaction took place in low yields only in the case of aliphatic N,N‐disubstitution. Also the reaction of 2‐phenyl enaminones Id‐g with chlorosulfene occurred as with sulfene, giving a mixture of cycloadducts which were dehydrochlorinated in situ with DBN to afford N,N‐di‐substituted 4‐amino‐5,6‐dihydro‐8‐phenyl‐1,2‐oxathiino[6,5‐f]quinazoline 2,2‐dioxides III generally in satisfactory yields. Compounds III could not be dehydrogenated either by DDQ in boiling benzene or by palladium on carbon in boiling p‐cymene.
Nitrogen bridgehead compounds. Part 69. Studies on quinolizine derivatives. Part 3. Infrared and 1H NMR spectroscopic studies of quinolizine derivatives and their monocyclic tautomers
Authors: Schwartz Angéla , Pál Zoltán , Szabó László , Hermecz István , Mészáros Zoltán 
Published: April 2009

AbstractInfrared and 1H nmr spectra of 4‐oxo, 1, and 4‐imino, 2, quinolizine derivatives or their monocyclic tautomers 3, 4 have been comparatively studied. The number of ethoxycarbonyl groups, the signals of the hetero proton, the C(9)‐H, and the C(6)‐CH3 group in the 1H nmr spectrum, moreover the N‐H stretching vibration bands proved to be diagnostically important for monocyclic or bicyclic as well as for 4‐oxo or 4‐imino structures. A weak intramolecular hydrogen bridge in compounds 2b and 2f, a strong chelate type hydrogen bridge in 4E and 4F=G could have been demonstrated as well.
A facile synthesis of pyrrolo[1,2‐a]pyrimidines and pyrrolo[1,2‐a]imidazoles
Authors: Ross John R. , Vishwakarma Lal C. , Sowell J. Walter 
Published: April 2009

AbstractThe one‐step synthesis of 8‐t‐butoxycarbonyl‐6,7‐dimethyl‐2‐oxo‐1,2,3,4‐tetrahydropyrrolo[1,2‐a]pyrimidine from acetyl methyl carbinol, 3‐aminopropionic acid, and t‐butyl cyanoacetate is reported. Utilizing a similar technology under basic conditions, 7‐substituted 5,6‐dimethyl‐2‐oxo‐2,3‐dihydro‐(1H)‐pyrrolo[1,2‐a]imidazole is synthesized from acetyl methyl carbinol, ethyl glycinate, and the appropriate acetonitrile.
Synthesis and spectra of some triazolo and triazinophthalazines of possible hypotensive activity
Authors: Allah Hassan M. Faid , Soliman Raafat 
Published: April 2009

AbstractCyclization of hydralazine 1 with acid chlorides or ethyl cyanoacetate gave the appropriate s‐triazolo derivatives, while with ketoesters or 1,2‐dicyclohexanedione it afforded the as‐triazino derivatives. Reaction of 1 with ketosteroids yielded hydrazones. Preliminary cardiovascular testing revealed possible hypotensive activity of some of these derivatives.
Synthesis of 1‐ and 3‐amino‐5‐t‐butyl‐1H‐ and ‐3H‐v‐triazolo[4,5‐d]pyrimidines as hetaryne precursors
Authors: Tielemans Michel , Christophe Daniel , Promel Robert 
Published: April 2009

AbstractThe synthesis of the title compounds 6 and 8 has first been accomplished by reaction of O‐mesitylsulfonyl‐hydroxylamine with 5‐t‐butyl‐3H‐v‐triazolo[4,5‐d]pyrimidine (5) whose preparation is reported in detail. However the preferred route for the synthesis of the 3‐amino derivative 8 is based upon the preparation of 3‐benzylideneamino‐5‐t‐butyl‐3H‐v‐triazolo[4,5‐d]pyrimidine (10), followed by the removal of the benzylidene protecting group. This critical step was effected by treatment of 10 with dilute hydrochloric acid, in the presence of 2,4‐dinitrophenylhydrazine.The diazotization of 5‐amino‐4‐hydrazino‐2‐t‐butylpyrimidine gave predominantly the tetrazolo[1,5‐c]‐pyrimidine 13 along with a small amount of compound 8.
The reaction of β‐aminoenones with substituted acetonitriles. Regiospecific synthesis of 2(1H)‐pyridones
Authors: Alberola Angel , Andrés Celia , Ortega Alfonso González , Pedrosa Rafael , Vicente Martina 
Published: April 2009

AbstractUnsymmetrically substituted β‐aminoenones react with malononitrile, cyanomethylphenylsulfone, benzoyl‐acetonitrile and ethyl cyanoacetate, in very mild conditions, to yield regiospecifically 3‐functionalized 2(1H)‐pyridones in high yields.
Synthesis of some furochromonesulfonamide derivatives with potential pharmacological activity
Authors: Elgamal M. Hani A. , Shalaby Nagwa M. M. , Duddeck Helmut , Rosenbaum Doris 
Published: April 2009

AbstractA number of visnagin‐9‐sulfonamides 1‐3 have been prepared. In two instances side‐products have been isolated in which the γ‐pyrone ring is opened. All compounds were characterized by high‐field 1H and 13C nmr and mass spectra.
Synthesis of 2′,3′‐dihydrospiro[benzofuran‐2(3H),4′(1′‐H)isoquinoline]s. A novel heterocyclic ring system
Authors: Klein Joseph T. , Davis Larry , Effland Richard C. 
Published: April 2009

AbstractThe synthesis of a novel 2′,3′‐dihydrospiro(benzofuran‐2(3H),4′(1′H)isoquinoline] ring system (IV) by a nucleophilic aromatic fluoride displacement‐cyclization is described. Preparation of various derivatives of IV as well as the precursor 4‐(2‐fluorobenzyl)‐1,2,3,4‐tetrahydro‐4‐isoquinolinols is also described.
Observations on the reduction of aryl nitro groups with palladium‐sodium borohydride
Authors: Smith William B. 
Published: April 2009

AbstractThe reduction of aryl nitro groups by the palladium‐sodium borohydride system can be controlled in some instances to give products differing from those of catalytic hydrogenation. With six equivalents of borohydride added to the catalyst 2,2′‐dinitrobiphenyl formed only 2,2′‐diaminobiphenyl. With added sodium hydroxide and varying amounts of borohydride and catalyst, the reduction can be controlled to give benzo[c]cinnoline, benzo[c]cinnoline 5‐oxide or benzo[c]cinnoline 5,6‐dioxide. In a closed system, the reagents reduce both the nitro and olefin functional groups in 6‐nitro‐5,8‐dimethoxy‐1,4‐dihydro‐1,4‐ethano‐naphthalene. In an open flask flushed with argon, the reduction is confirmed to the nitro group. Reduction of 2‐chloro and 4‐chloronitrobenzene with palladium‐borohydride gives substantial yields of the appropriate chloroanilines. In contrast, hydrogen and palladium give aniline as the major product from each of these. These results suggest that the addition of sodium borohydride to palladium on carbon produces a reductive entity differing from that of catalytic hydrogenation.
Synthesis of multisulfur‐containing substituted dibenzothiophenes
Authors: Dunkerton L. V. , Barot B. C. , Nigam A. 
Published: April 2009

AbstractNew substituted dibenzothiophenes have been prepared and characterized. Selective functionalizations utilized substitutions of lithiodibenzothiophenes available from established methodology. New dibenzothiophenes prepared include 2‐(bromomethyl)dibenzothiophene (5), 2‐(thiomethyl)dibenzothiophene (6), 2‐S‐phenylthiomethyldibenzothiophene (24), 2‐S‐(2′‐dibenzothiophenylmethyl)thiomethyldibenzothiophene (25), 2‐S‐methyldibenzothiophene (30), 2‐S‐(p‐bromophenyl)dibenzothiophene (31), and 2‐S‐benzyldibenzothiophene (33). Dibenzothiophenes prepared from 4‐lithiodibenzothiophene include 4‐(bromomethyl)dibenzothiophene (13), 4‐(thiomethyl)dibenzothiophene (14), 4‐S‐(4′‐dibenzothiophenylmethyl)thiomethyldibenzothiophene (26), 4‐S‐(p‐tolyl)dibenzothiophene (34), 4‐S‐methyldibenzothiophene (35), 4‐S‐benzyldibenzothiophene (37), and 4‐S‐(p‐bromophenyl)dibenzothiophene (36). Similarly new 2,8‐disubstituted dibenzothiophenes prepared include 2,8‐bis(thiomethyl)dibenzothiophene (19), 2,8‐bis(S‐benzyl)dibenzothiophene (27), 2,8‐bis(S‐p‐tolyl)dibenzothiophene (28) and 2,8‐bis(S‐methyl)dibenzothiophene (29). The cmr chemical shift data for these dibenzothiophenes are also included.
Synthesis of a series of pyrrole‐1‐acetic acids as potential antiinflammatory agents
Authors: Ross John R. , Sowell J. Walter 
Published: April 2009

AbstractA series of 3‐substituted 2‐amino‐4,5‐dimethylpyrrole‐1‐acetic acid derivatives were synthesized. The condensation of acetyl methyl carbinol, ethyl glycinate, and the appropriate acetonitrile yielded ethyl 3‐substituted 2‐amino‐4,5‐dimethylpyrrole‐1‐acetate, which was consequently hydrolyzed to produce the corresponding carboxylic acid. The acetamide and trifluoroacetamide series were synthesized by reacting the ethyl 2‐aminopyrrole‐1‐acetates with acetyl chloride or trifluoroacetic anhydride respectively. The corresponding 2‐acetamidopyrrole‐1‐acetic acids were formed by basic hydrolysis of the ethyl esters.
Reduction of α,β‐unsaturated nitroalkenes with borane and borohydrides. A convenient route to 3‐nitro‐, 3‐hydroxylamino‐, and 3‐amino‐2h‐1‐benzopyran derivatives
Authors: Varma Rajender S. , Gai Yuan‐Zhu , Kabalka George W. 
Published: April 2009

AbstractThe borohydride catalyzed borane reduction of 3‐nitrochromenes provided a facile route to a variety of 3‐hydroxylamino‐ 5 and 3‐amino‐2H‐1‐benzopyranes 6. Reduction with methoxyborohydride species, on the other hand, provided 3‐nitrochromans 2,4.
Synthesis and reactions of halo‐, nitro‐, and arylazo‐substituted 3‐acetyltropolones. Formation of heterocycle‐fused troponoid compounds
Authors: Li Zhi‐Hong , Jin Zhong‐Tian , Yin Bing‐Zhu , Imafuku Kimiaki 
Published: April 2009

Abstract3‐Acetyltropolone (1) reacted with bromine, iodine, and nitric acid to afford respectively 3‐acetyl‐5,7‐di‐bromotropolone (2), 3‐acetyl‐7‐iodotropolone (3), and 3‐acetyl‐5‐nitro‐ (4) and 3‐acetyl‐5,7‐dinitrotropolone (5). Azo‐coupling reactions of 1 gave 3‐acetyl‐5‐arylazotropolones 7a‐f. The Schmidt reactions of 2 and 3 gave respectively 5,7‐dibromo‐ (9) and 7‐iodo‐2‐methyl‐8H‐cyclohept[d]oxazol‐8‐one (10), while 4 gave 3‐acetamido‐5‐nitrotropolone (11). Compounds 2 and 4 reacted with hydroxylamine to give 3‐methyl‐8H‐cyclohept[d]isoxazol‐8‐ones 12 and 13. The reactions of 2, 3, and 4 with hydrazine gave 3‐methyl‐1,8‐dihydrocycloheptapyrazol‐8‐ones 15, 16, and 17.
Synthetic studies toward 4H‐1,3‐benzodioxin‐2‐ones
Authors: Podraza Kenneth F. 
Published: April 2009

AbstractThe investigation into the synthesis of 4H‐1,3‐benzodioxin‐2‐ones, utilizing the corresponding 2‐(hydroxy‐methyl)phenol as the starting diol, is described. The results illustrate that the synthesis of 4H‐1,3‐benzodi‐oxin‐2‐ones can be achieved utilizing carefully controlled reaction conditions, in a 3–15% yield.
Reaction of 4‐acylaminomethylpyridine N‐oxides with 5‐monosubstituted barbituric acids in presence of acetic anhydride
Authors: Braña M. F. , Castellano J. M. , Redondo M. C. , Yunta M. J. R. 
Published: April 2009

AbstractThe 5‐alkyl‐5‐[(3,5‐dimethylbenzoylamino)(4‐pyridyl)methyl]barbituric acids are obtained in the title reactions, but they fail when barbituric or 5‐phenylbarbituric acids are used. These results are explained by the pKa values of barbituric acids.