bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lithiation and electrophilic substitution of 8‐chlorodibenz[b,f][1,4]‐oxazepine‐10‐tert‐butylcarbamate: The preparation of novel fused heterocyclic derivatives of 8‐chlorodibenzoxazepine
Authors: Li James J. , Chrusciel R. Alan , Norton Monica B. , Reitz David B. , Hagen Timothy J. , Tsymbalov Sofya , Hallinan E. Ann 
Published: March 2009

AbstractLithiation of 8‐chlorodibenz[b,f][1,4]oxazepine‐10‐tert‐butylcarbamate (1) is described. Electrophilic substitution of the resulting N‐Boc dibenzoxazepine α‐ lithioamine 2 with ketones, aldehydes, nitriles, iso‐cyanates and imines, followed by an in‐situ cyclization, gave fused carbamates 5–26, fused 2H‐imidazol‐2‐ones 27–29, fused hydantoins 30–32, and fused ureas 33–35, respectively, in 11–66% yield.
Selective alkylation of pyrrole by phase transfer catalysis in the absence of solvent
Authors: Díez‐Barra E. , De La Hoz A. , Sánchez‐Migallón A. , Loupy A. 
Published: March 2009

AbstractSelective N‐alkylation of pyrrole is performed, in good yield and by a very simple method, using Phase Transfer Catalysis in the absence of solvent.
Synthesis and NMR characterization of a dioxa‐analog of benzo[a]pyrene: The 1‐benzopyrano[6,5,4‐mna]‐xanthene (1,6‐dioxabenzo[a]pyrene)
Authors: Buisson J.‐P. , Demerseman P. , Platzer N. 
Published: March 2009

Abstract1,6‐Dioxabenzo[a]pyrene, the first dioxa‐analog of benzo[a]pyrene, was synthesized from 5‐methoxy‐1‐naphthol in an eight‐step reaction involving two peri‐heterocyclizations.
Selenium heterocycles. XLI. Syntheses of substituted thiazolo, selenazolo, 1,2,3‐thiadiazolo and 1,2,3‐selenadiazoloquinolines
Authors: Shafiee A. , Rezayazdi M. 
Published: March 2009

AbstractThe reaction of thionyl chloride with the semicarbazone 2 gave 4,5‐dihydro[1,2,3]thiadiazolo[4,5‐f]quinoline. Selenium dioxide oxidaion of compound 2 gave 4,5‐dihydro[1,2,3]selenadiazolo[4,5‐f]quinoline (4) and the aromatic analog 5. Thermolysis of compound 5 yielded [1,4]diselenino[2,3‐f:5,6‐f′]diquinoline (6). Reaction of selenourea with α‐bromoketone 7 gave 2‐amino‐4,5‐dihydroselenazolo[4,5‐f]quinoline (8). Compounds 9 and 10 were prepared from the reaction of selenobenzamide and thiobenzamide with compound 7.
Acridine derivatives. VI. Redox chemistry of novel 9‐anilinoacridines with antitumor activities
Authors: Kimura Michio , Okabayashi Ichizo , Inoue Hiroaki 
Published: March 2009

AbstractIn order to elucidate the mechanism of deoxyribonucleic acid (DNA) strand breaks caused by 9‐anilino‐acridine DNA intercalators, the antitumor activity of L1210, P388 and the reduction‐oxidation (redox) reaction of 9‐anilinoacridines were studied. The redox reaction induced by two electrons causing structural changes in quinone diimines of 9‐anilinoacridines is believed to be an important factor in DNA strand breaks and was examined by means of temperature‐dependent nuclear magnetic resonance and cyclic voltammetry. The redox reaction of 9‐anilinoacridines is induced by the effect of a low‐energy electron transfer from the acridine to the aniline ring. We propose that the redox reaction plays an important role in the DNA strand cleavage of 9‐anilinoacridine when it is intercalated into double‐strand DNA.
3‐Phenacylidene‐3,4‐dihydro‐1H‐pyrido[2,3‐b]pyrazin‐2‐ones and 2‐Phenacylidene‐1,2‐dihydro‐4H‐pyrido[2,3‐b]pyrazin‐3‐ones
Authors: Seki Taketsugu , Sakata Hisanori , Iwanami Yasuo 
Published: March 2009

AbstractCondensation of 2,3‐diaminopyridine (1) with ethyl o‐, m‐ and p‐substituted benzoylpyruvates 2–9 gave two isomeric products. The preferential formation of one or the other isomer has been achieved by different reaction conditions. All the products appear to exist in the enamine form as evidenced by their 1H nmr and ir spectra.
Solid state structure of NH‐pyrazoles not easily amenable to crystal structure determinations: The case of 3(5)‐phenyl‐5(3)‐methylpyrazole and 3,5‐diphenyl‐4‐methylpyrazole
Authors: Elguero JosÉ , Jagerovic Nadine , Foces‐Foces ConcepciÓN , Cano Félix H. , Roux MarÍA Victoria , Aguilar‐Parrilla Francisco , Limbach Hans‐Heinrich 
Published: March 2009

AbstractThe structures of 3(5)‐methyl‐5(3)‐phenylpyrazole (polymorph B) and 3,5‐diphenyl‐4‐methylpyrazole in the solid state cannot be determined by X‐ray crystallography due to the lack of suitable monocrystals. The combined use of CPMAS nmr, DSC and powder diffraction provides information about the behaviour of these pyrazoles in the solid state, particularly, about N‐H ⃛N intermolecular proton transfer. 3(5)‐Methyl‐5(3)‐phenylpyrazole is an example of the influence of polymorphism on the proton exchange since polymorph A (a tetramer formed by a mixture of both tautomers) presents the phenomenon but polymorph B (formed exclusively by 3‐phenyl‐5‐methyl tautomer) is devoid of it.
Tautomeric behavior of 3‐(arylhydrazono)methyl‐2‐oxo‐1,2‐dihydroquinoxalines between the hydrazone imine and diazenyl enamine forms in acidic media. Solvent and substituent effects
Authors: Kurasawa Yoshihisa , Hosaka Tomoyoshi , Takada Atsushi , Kim Ho Sik , Okamoto Yoshihisa 
Published: March 2009

AbstractThe 3‐(arylhydrazono)methyl‐2‐oxo‐1,2‐dihydroquinoxalines 1a‐h and 2a‐e showed tautomeric equilibria between the hydrazone imine A and diazenyl enamine B forms in a series of mixed trifluoroacetic acid/dimethyl sulfoxide media. The substituent and solvent effects on the tautomer ratios of A to B in a series of mixed media were studied for compounds 1a‐h and 2a‐e by the nmr spectroscopy. In compounds 1a‐h and 2a‐e, the ratios of the tautomer B gradually increased with elevation of acid concentration, and the tautomer B exclusively existed in trifluoroacetic acid media. The various acid concentrations (C v/v%, C' mol/1) giving the 1:1 tautomer ratios [C(A:B = 1:1), C'(A:B = 1:1)] were obtained from all compounds (Figures 1–13), and the linear correlation of the Hammett σp values with the log C'(A:B = 1:1) values were observed for compounds 1a‐h. The larger Hammett σp values brought about the larger acid concentrations C(A:B = 1:1) in compounds 1a‐h and 2a‐e, indicating that the higher acid concentration was required for the stabilization of tautomer B possessing the electron‐withdrawing p‐substituents R1, which weakened the basicity of the azo nitrogen atom. Moreover, the ester group R2 of compounds 2a‐e was found to decrease the electron density of the azo nitrogen atom, since the acid concentration C(A:B = 1:1) of compound 2c (R1 = H, R2 = COOMe, σp = O) was 52%, whose value was larger than that of compound 1b (R1 = CN, R2 = H, σp = 0.66) [C(A:B = 1:1) = 42%].
Electron impact ionization mass spectra of 6‐carbamoyloxy‐3‐oxo‐3,6‐dihydro‐2H‐pyran and 5H‐pyrano[3,2‐d]‐oxazole‐2,6‐dione derivatives
Authors: Couladouros Elias A. , Haroutounian Serkos A. 
Published: March 2009

AbstractThe electron impact ionization mass spectra of 6‐carbamoyloxy‐3‐oxo‐3,6‐dihydro‐2H‐pyrans show a weak molecular ion peak and a base peak of m/z 84 resulting from a retro Diels‐Alder fragmentation. The bicyclic system 5H‐pyrano[3,2‐d]oxazole‐2,6‐dione gives a characteristic fragmentation pattern with a very stable fragment of oxazolenone.
Synthesis of 1‐(dimethylsulfamoyl)‐2‐ and 5‐imidazolecarboxaldehydes. Rearrangement of 1‐(dimethylsulfamoyl)‐5‐imidazole‐carboxaldehyde to the 4‐carboxaldehyde
Authors: Kim Jang‐Woo , Abdelaal Salma M. , Bauer Ludwig , Heimer Norman E. 
Published: March 2009

AbstractLithiation of 1‐(dimethylsulfamoyl)imidazole by n‐butyllithium, followed by substitution with dimethylformamide provided 1‐(dimethylsulfamoyl)‐2‐imidazolecarboxaldehyde in 19% yield. When 1‐(dimethylsulfamoyl)‐2‐(tert‐butyldimethylsilyl)imidazole was lithiated by sec‐butyllithium, followed by methyl formate, there was obtained 1‐(dimethylsulfamoyl)‐2‐(tert‐butyldimethylsilyl)‐5‐imidazolecarbox‐aldehyde (57%). Removal of the silyl group by acetic acid yielded 1‐(dimethylsulfamoyl)‐5‐imidazolecarbxaldehyde (11, 96%) as a gum. Isomerization of 11 took place slowly at room temperature (10 days), or faster in tetrahydrofuran solution containing triethylamine (2 hours) to form crystalline 1‐(dimethylsul‐famoyl)‐4‐imidazolecarboxaldehyde (12) in 68% yield. Proton and carbon‐13 nmr spectra were analyzed to determine the structure of the isomers. However, only X‐ray crystallography established the structure of 1‐(dimethylsulfamoyl)‐4‐imidazolecarboxaldehyde, unequivocally. A mechanism for the isomerization of 11 to 12 is proposed.
Progress in the chemistry of quinoxaline N‐oxides and N,N′‐dioxides
Authors: Kurasawa Yoshihisa , Takada Atsushi , Kim Ho Sik 
Published: March 2009

AbstractThis review describes the 1,3‐dipolar cycloaddition reaction, deoxygenation, deoxygenative transformation, ring transformation and photochemical reaction of quinoxaline N‐oxides and N,N′‐dioxides.
Carbolines. Part VII. Anisidines, convenient tools to synthesize hydroxy‐β‐carbolines
Authors: Rocca Patrick , Marsais Francis , Godard Alain , Quéguiner Guy , Adams Luqman , Alo Babajide 
Published: March 2009

AbstractThe paper describes a convenient synthesis of hydroxy‐β‐carbolines from commercial anisidines based on key steps such as metalation, cross‐coupling and cyclization. The first total synthesis of a major cyto‐toxic constituent of a marine bryozoan is also reported, the 8‐hydroxy‐1‐vinyl‐β‐carboline.
Synthesis of 2‐aminoquinazolines from ortho‐fluoroketones
Authors: Hynes John B. , Campbell Johnny P. , Hynes John D. 
Published: March 2009

AbstractThe reactions of ten ortho‐fluoroketones with guanidine carbonate in N,N‐dimethylacetamide were investigated as a new synthetic approach to 2‐amino‐4‐alkyl‐ and 2‐amino‐4‐arylquinazolines. The yields obtained ranged from low to moderate and were highly dependent upon the nature of the substituents on the reactant. Eight new quinazolines were elaborated in this study.
Rearrangements of 5‐azidoisoxazoles
Authors: Anderson David J. , Muchmore Christine R. 
Published: March 2009

Abstract5‐Azidoisoxazoles are prepared via displacement of a chlorine atom in 5‐chloroisoxazoles with azide ion. These 5‐azidoisoxazoles contain an unsaturated group (olefin, aldehyde, oxime or hydrazone) in the 4‐position which participates during thermal decomposition of the azide. Two types of products are formed which are non‐interconvertible: (i) bicyclic isoxazoles which result from direct attack of the azide or nitrene on the unsaturated group; (ii) monocyclic pyrroles and pyrazoles which result from ring opening followed by bond reorganization and subsequent ring closure. Mechanisms for the two discrete processes are discussed.
Synthesis of 7H‐pyrido[2,3‐c]carbazoles from 5‐bromo‐8‐methoxyquinolines via coupling and azide cyclization reactions
Authors: Trécourt Françis , Mongin Florence , Mallet Marc , Quéguiner Guy 
Published: March 2009

AbstractA new strategy for the synthesis of substituted 7H‐pyrido[2,3‐c]carbazoles has been developed from substituted 5‐bromoquinolines by using cross‐coupling reaction with (2‐aminophenyl)boric acids, followed by a regioselective azide cyclization.
The synthesis of 5‐arylpyrrolo[3,2‐b]pyridines and 7‐arylpyrrolo[3,2‐b]pyridines: Addition of 3‐aminopyrroles to aryl enaminones
Authors: Birnberg Gary H. , Fanshawe William J. , Francisco Gerardo D. , Epstein Joseph W. 
Published: March 2009

AbstractA series of 5‐arylpyrrolo[3,2‐b]pyridines 1 was synthesized by addition of 3‐aminopyrroles to aryl enaminones. One example of a 7‐arylpyrrolo[3,2‐b]pyridine 2 was obtained as a minor product along with the 5‐aryl isomer, by a modification of the reaction sequence.
Friedländer reaction of 3‐acetyltropolone: Synthesis of 3‐(2‐quinolyl)tropolones
Authors: Piao Ming‐Zhu , Imafuku Kimiaki 
Published: March 2009

Abstract3‐Acetyltropolone (1a) reacted with 2‐aminobenzaldehydes in the presence of sodium ethoxide to afford 3‐(2‐quinolyl)tropolone (3aa) in 96% yield. Methyl‐ and isopropyl‐substituted tropolones 1b,c also gave six 3‐(2‐quinolyl)tropolones in excellent yields. The compound 3aa was allowed to stand in 40% aqueous methylamine solution to give 7‐methylamino‐2‐(2‐quinolyl)tropone (4).
Conversion of 3,n‐dithiabicyclo[n.3.1]alkatrienes to bicyclo[n.3.1]alkapentaenes
Authors: Doomes Earl , Mcknight Alice A. 
Published: March 2009

AbstractThe application of the Ramberg‐Backlund reaction in the conversion of several 3,n‐dithiabicyclo[n.3.1]alkatrienes to the corresponding bicyclo[n.3.1]alkapentaenes is reported. Proton magnetic resonance and ultraviolet spectra were utilized in the overall characterization of bicyclo[8.3.1]tetradeca‐2,8,10,12,1(14)‐pentaene, bicyclo[9.3.1]pentadeca‐2,9,11,1(15)‐pentaene, and their precursors. The final step in the synthesis was a Ramberg‐Backlund of bis‐α,α′‐chloro sulfone. The intermediate, 2‐chloro‐3‐thiabicyclo[9.3.1]pentadeca‐9,11,13,1(15)‐tetraene 3,3‐dioxide, was isolated and characterized. The structure and stability of the bridged α,α′‐dichloro sulfide intermediates were examined.
Theoretical study of thieno[3,4‐d]thiepin and furo[3,4‐d]thiepin as dienes in the diels‐alder reaction
Authors: Jursic Branko S. 
Published: March 2009

AbstractTheoretical study of thiophene and furan c‐fused rings with unsaturated seven membered rings with oxygen or sulfur as dienes for Diels‐Alder reactions was conducted with the semiempirical Austin Model 1 (AMI). Four approaches were considered: frontier orbital theory, resonance stability of the dienophiles determined through heat of hydrogenation, progress of the reaction through bond orders, and the estimation of the reaction barriers. It was determined that the most unreactive species with the highest resonance stability are sulfur heterocyclic compounds, while furan derivatives are the most reactive. Using o‐quinonoid episulfide as an intermediate was rejected because the estimated activation energy for its formation is too high. The possibility of a three bond formation in the transition state of thieno[3,4‐d]thiepin reaction with ethylene was considered and rejected on the basis of AMI estimated activation energy. The S‐methylated derivatives of thieno[3,4‐d]thiepin were predicted to react with less reactive dienophiles like ethylene under moderate reaction conditions. If thieno[3,4‐d]thiepin is not activated through S‐methylation then a reactive dienophile and drastic reaction conditions are predicted to be necessary to force the cycloaddition reaction. The obtained results are in agreement with experimental evidence.
Nitrosation of methyl 2‐acylamino‐3‐dimethylaminopropenoates. A simple conversion of n‐acylglycines into 5‐substituted 1,2,4‐Oxadiazole‐3‐carboxylates
Authors: Kmetiĉ Matej , Stanovnik Branko 
Published: March 2009

AbstractA novel simple synthesis of 5‐substituted‐1,2,4‐oxadiazole‐3‐carboxylates 5 from N‐acylglycines 1, which are transformed with DMF in the presence of phosphorus oxychloride into 2‐substituted‐4‐dimethyl‐aminomethyleneoxazol‐5(4H)‐ones 2, followed by opening into 2‐aroylamino‐3‐dimethylamino‐propenoates 3, and nitrosation to give the oximes 4 as intermediates, which cyclize spontaneously into 5‐substituted‐1,2,4‐oxadiazole‐3‐carboxylates 5. The compounds 2 can be transformed into 5 without isolation of 3 and 4.
Synthesis of a 1,8‐naphthyridin‐5‐one derivative via an intramolecular 1,3‐dipolar cycloaddition reaction
Authors: Read Mark W. , Ray Partha S. 
Published: March 2009

AbstractSynthesis of a 1,8‐naphthyridin‐5‐one derivative [(5,6,7,8‐tetrahydro‐(3‐chloro‐6‐hydroxymethyl‐8‐methyl)‐1,8‐naphthyridin‐5‐one (9)] is described starting from 2‐chloronicotinic acid using an intramolecular 1,3‐dipolar cycloaddition reaction as the key step.
The transformations of 4‐heteroarylaminomethylene‐5(4H)‐oxazolones into dehydropeptide derivatives
Authors: Aljaẑ‐Roẑiĉ Mateja , Svete Jurij , Stanovnik Branko 
Published: March 2009

Abstract2‐Phenyl‐4‐heteroarylaminomethylene‐5(4H)‐oxazolones 3, which were prepared from the corresponding N,N‐dimethyl‐N'‐heteroarylformamidines 1 and hippuric acid 2 in acetic anhydride, react with amino acids giving dehydropeptide derivatives 4, 5, and 6 as products. Dehydration of N‐protected peptides 7–10, containing glycine at the C‐terminal, followed by the reaction with formamidines 1 gave 2‐substituted‐4‐heteroarylaminomethylene‐5(4H)‐oxazolones 11–14.
Thiazolo[4,3‐c][1,4]benzodiazepines. I. Synthesis of amidine derivatives
Authors: Gillard Alain‐Claude , Rault Sylvain , Boulouard Michel , Robba Max 
Published: March 2009

AbstractReactivity of 1,2,3,10,11,11a‐hexahydro‐5H‐thiazolo[4,3‐c][1,4]benzodiazepin‐5‐one‐11‐thione and 1,2,3,10,11,11a‐hexahydro‐5H‐thiazolo[4,3‐c][1,4]benzodiazepine‐5,11‐dithione was evaluated against various amines. The synthetic pathways involved in these reactions which led to new thiazolo[4,3‐c]‐[1,4]benzodiazepine amidines are described.
The magnesium bromide induced claisen condensation reaction of N‐acylpyrazoles
Authors: Kashima Choji , Takahashi Katsumi , Fukusaka Kiyoshi 
Published: March 2009

AbstractN‐Acylpyrazoles formed the 5‐membered C=O‐Mg‐N‐2 chelate complexes with magnesium bromide which afforded the Claisen condensation products by the action of tertiary amine through the corresponding enolate.
Synthesis of 5H‐imidazo[5,1‐a]isoindole: Photocyclization of N,N′ ‐bis(o‐chlorobenzyl)imidazolium chloride and N‐(o‐chlorobenzyl)imidazole
Authors: Byun Young‐Seok , Jung Chang‐Hee , Park Yong‐Tae 
Published: March 2009

AbstractA N‐heterocyclic compound containing two hetero atoms, imidazo[5,1‐a]isoindole, was synthesized in 40% yield by the intramolecular photocyclization of N,N'‐bis(o‐chlorobenzyl)imidazolium salts 1 in water (neutral or pH ∼4) or of N‐(o‐chlorobenzyl)imidazole 2, in aqueous acid (pH −4). However, the photocyclized compound 3 was not formed effectively in basic aqueous solution (3 equivalents of sodium hydroxide or pyridine) or in acetonitrile by the photochemical reaction of N,N'‐bis(o‐chlorobenzyl)imidazolium salts 1 or N‐(o‐chlorobenzyl)imidazole (2).
Pyrrolothieno[1,4]diazepines part III: Synthesis of amino, hydrazino and mercapto derivatives
Authors: Boulouard Michel , Rault Sylvain , Dallemagne Patrick , Alsaïdi Abdellah , Robba Max 
Published: March 2009

AbstractTreatment of 2‐(2‐formyl‐1H‐pyrrol‐1‐yl)‐3‐thiophenecarbonitrile by sodium percarbonate afforded, in a one‐pot sequence and on a multigram scale, 5,6‐dihydro‐6‐hydroxy‐4H‐pyrrolo[1,2‐a]thieno‐[3,2‐f][1,4]diazepin‐4‐one whose reactivity towards various nucleophiles like amines, hydrazines and thiols was evaluated.
On the reaction of isothiosemicarbazides with heterocumulenes. Part I
Authors: Ernst Steffen , Schulze Klaus 
Published: March 2009

AbstractIsothiosemicarbazides 2 react with acyl isothiocyanates under addition‐cyclization to yield 1,3,4‐thiadiazoline‐2‐imines 3 as well as the isomeric 2‐amino‐substituted 1,3,4‐thiadiazolium‐5‐acylaminides 3′. In a similar manner the 2‐hydrazino‐substituted 1,3‐thiazoline 4 adds ethoxycarbonyl isothiocyanate to give the thiosemicarbazide 5, which undergoes a rearrangement to the 1,3,4‐thiadiazoline‐2‐imine 5′. The [2+2] cycloreversion of 3d involving ethoxycarbonyl iso(thio)cyanate and the thermal induced Dimroth rearrangement of 3′f and h are also discussed.
Pharmacophoric requirements for cannabinoid side chains. Naphthoyl and naphthylmethyl substituted Δ8‐tetrahydrocannabinol analogs
Authors: Papahatjis Demetris P. , Kourouli Therapia , Makriyannis Alexandras 
Published: March 2009

AbstractWe have synthesized hybrids of classical cannabinoids and aminoalkylindoles by combining the dibenzopyran structure of Δ8‐tetrahydrocannabinol with the ketonaphthyl or 1‐naphthylmethyl moieties found in aminoalkylindoles in order to investigate the role of the ketonaphthyl and 1‐naphthylmethyl pharmacophores in cannabimimetic activity.
Synthesis and anti‐HIV‐1 activity of 1,5‐dialkyl‐6‐(arylselenenyl)uracils and ‐2‐thiouracils
Authors: Kim Dae‐Kee , Kim Hun‐Taek , Lim Jinsoo , Gam Jongsik , Kim Young‐Woo , Kim Key H. , Shin Young Oh 
Published: March 2009

AbstractThe 1,5‐dialkyl‐6‐(arylselenenyl)uracils 10a‐h and ‐2‐thiouracils 10i‐p have been synthesized as potential anti‐HIV‐1 agents. Cyclization of N‐alkyl‐N'‐[3,3‐di(methylthio)‐2‐alkylacryloyl]ureas 6a‐d and ‐thioureas 6e‐h in acetic acid either containing a catalytic amount of methanesulfonic acid at 80°or containing 1 equivalent of methanesulfonic acid at room temperature afforded 1,5‐dialkyl‐6‐(methylthio)uracils 7a‐d in 84–96% yields and 1,5‐dialkyl‐5,6‐dihydro‐6,6‐di(methylthio)‐2‐thiouracils 11a‐d in 88–99% yields, respectively. Oxidation of 7a‐d and 11a‐d with either 3‐chloroperoxybenzoic acid in benzene or aqueous sodium periodate solution in methanol gave 1,5‐dialkyl‐6‐(methylsulfonyl)uracils 8a‐d in 88–98% yields and 1,5‐dialkyl‐6‐(methylsulfinyl)‐2‐thiouracils 12a‐d in 57–73% yields, respectively, which were subsequently treated with arylselenol 9a‐b in ethanolic sodium hydroxide solution to afford 10a‐p in 6099% yields. Of these compounds, 6‐[(3,5‐dimethylphenyl)selenenyl]‐5‐isopropyl‐1‐(3‐phenylpropyl)uracil (10h) inhibited HIV‐1 replication in MT‐4 cells at a 50% effective concentration (EC50) of 0.0006 μM with a selective index of 44833, which is 7.7‐fold more potent than AZT.
Synthesis of N‐acyl‐2‐pyrrolidinones from the corresponding N‐acyl‐GABA derivatives
Authors: Rekatas George V. , Demopoulos Vassilis J. , Kourounakis Panos N. 
Published: March 2009

AbstractIn this work, the synthesis of 1‐(pyridine‐3‐carbonyl)pyrrolidin‐2‐one (1a) and 1‐(2‐propyl‐1‐pentanoyl)pyrrolidin‐2‐one (1b) by cyclization of the corresponding GABA derivatives, is reported. Two different methods are developed. For the synthesis of 1a, the parent molecule 4‐[(pyridine‐3‐carbonyl)‐amino]butanoic acid (2a) is treated first with thionyl chloride and then with triethylamine. The second derivative, 1b, is produced by an intramolecular dehydration of 4‐(2‐propylpentanoylamino)butanoic acid (2b) using an acid catalyst.
Condensation reactions of benzils with ureas in ethylene glycol
Authors: Lee Chang Kiu , Kim Sun Hee , Kim Yong Bun 
Published: March 2009

AbstractReactions of benzils and urea in ethylene glycol at 180° for 1‐2 hours gave 2,4,5‐triaryloxazoles as major products and bicyclic imidazoimidazole‐2,5‐diones as minor products. N‐Methylurea and N‐phenylurea gave the oxazoles under similar conditions. The solvent seemed to assist the formation of oxazole by eliminating the isocyanate components as ethylene glycol biscarbamates.
Synthesis of quinoxaline 1,4‐dioxides from 4,5(6,7)‐dimethylbenzofuroxan
Authors: Takabatake Tohru , Miyazawa Tomoyuki , Hasegawa Minoru 
Published: March 2009

AbstractIn this study, novel substituted quinoxaline 1,4‐dioxides were synthesized from novel substituted benzofuroxan. 4,5(6,7)‐Dimethylbenzofuroxan 3 was prepared by the thermal decomposition of 2,3‐dimethyl‐6‐nitrophenylazide 2. Novel quinoxaline 1,4‐dioxides derivatives were obtained using compound 3 and the enolic form of 1,3‐diketones 4 catalyzed by silica gel or molecular sieves. These reactions gave isomeric quinoxaline 1,4‐dioxides 5 and 6. These reactions of compound 3 may involve tautomers 4,5‐dimethylbenzofuroxan 3a, 6,7‐dimethylbenzofuroxan 3b on the surface of a solid catalyst.
3‐(2,5‐Dioxopyrrolidin‐1‐yl), 3‐(2,6‐dioxopiperidin‐1‐yl), and 3‐(1,3‐dioxoisoindolin‐2‐yl)rhodanines. a novel type of rhodanine derivatives
Authors: Hanefeld Wolfgang , Schlitzer Martin , Debski Norbert , Euler Helmut 
Published: March 2009

Abstract3‐Aminorhodanine 2 was reacted with cyclic anhydrides yielding 3‐(2,5‐dioxopyrrolidin‐1‐yl), 3‐(2,6‐dioxopiperidin‐1‐yl), and 3‐(1,3‐dioxoisoindolin‐2‐yl)rhodanine 6‐8, which in turn were condensated in 5 position with several aldehydes yielding the new rhodanine derivatives 9‐11.