bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantiomers and barriers to racemization of sterically hindered N‐aryl‐ and N‐heteroarylpyrroles
Authors: Vorkapić‐Furač Jasna , Mintas Mladen , Kastner Fritz , Mannschreck Albrecht 
Published: March 2009

AbstractThe N‐aryl‐ and N‐heteroaryl‐2,5‐dimethylpyrrole‐3‐carbaldehydes 2–8 have been synthesized by condensation of hexane‐2,5‐dione with the appropriate amine and subsequent Vilsmeier‐Haack formylation of the pyrrole ring. Diastereomeric association complexes of the racemic pyrrole 8 were studied by pmr chemical shifts and the splittings induced by (+)‐1‐(9‐anthryl)‐2,2,2‐trifluoroethanol. Enrichment of the enantiomers M and P of 2 and 6 was achieved by liquid chromatography on triacethylcellulose. The barrier to partial rotation about the C‐N bond in 6 was determined by thermal racemization and its lower limits in 2 and 8 were estimated.
Products from furans.XXISynthesis of novel oxygen containing heterocyclic isosteres of tyrosine derivatives
Authors: Georgiadis Minas P. , Haroutounian Serkos A. 
Published: March 2009

AbstractNovel oxygen containing heterocyclic isosteres of tyrosine and tyramine derivatives were synthesized. All new compounds contain the pyran ring as a consequence of their common route of preparation. Furthermore several methyl, ethyl, diethyl and isopropyl derivatives of the prepared amines were synthesized.
The reaction of carbanions from 3‐methyl‐5‐phenylisoxazole with electrophilic compounds
Authors: Alberola Angel , Calvo Luis , Rodríguez Teresa Rodríguez , Sañudo Carmen 
Published: March 2009

AbstractThe reactivity of 3‐methyl‐5‐phenylisoxazole against electrophilic compounds in the presence of different bases is studied. With n‐BuLi, alkylated products at C‐4 position and C‐3 methyl group, and, in a few cases, dialkylated isoxazoles are obtained. When the reactions are carried out with LICA, the nature of the alkylated products depends on the alkyl halide used. By using LICA‐TMEDA, as deprotonating system, regio‐selective reaction at the C‐3 methyl group is found.
Influence of benzo‐bridging on the stability of 6aλ4‐thia‐1,2,5,6‐tetraazapentalenic systems
Authors: L'Abbé Gerrit , Dehaen Wim , Bastin Lieve , Declercq Jean‐Paul , Feneau‐Dupont J. 
Published: March 2009

AbstractMethylation of the phenylhydrazone derived from 8‐oxo‐8H‐indeno[1,2‐d]‐1,2,3‐thiadiazole 5 with Meerwein's reagent furnishes the two methylated products 7 and 8. Single crystal X‐ray analyses of these compounds reveal no significant S…NPh interaction, thus excluding a thiapentalene structure.
Synthesis of some halogenated and disubstituted amino benzylacyclouridine derivatives
Authors: Pan Bai‐Chuan , Chen Zhi‐Hao , Rowe Elizabeth C. , Chu Shih‐Hsi 
Published: March 2009

Abstract1′‐Halogenomethyl, 1′‐azidomethyl and 1′‐disubstituted aminomethyl derivatives of BAU (5‐benzylacyclouridine) and BBAU (5‐benzyloxybenzylacyclouridine) were synthesized in the course of our studies of benzylacyclouridines. Two new and more convenient preparations of the previously known aminomethyl‐and hydroxymethyl‐parent compounds of these two series, AM‐BAU, AM‐BBAU and HM‐BBAU are also reported. These compounds were synthesized during a search for potential antiviral agents and pyrimidine phosphorylase inhibitors.
Correlation of 2‐, 3‐, 4‐ and disubstituted pyridine gas‐phase proton affinities with ab initio calculated energies at the sto‐3g basis set level
Authors: Caronna Tullio , Vittimberga Bruno M. 
Published: March 2009

AbstractTotal energies of 2‐, 3‐, 4‐ and disubstituted pyridines were calculated for the salt and the free base using ab initio molecular orbital calculations at the STO‐3G basis set level [2]. In each set, the difference in energy, ΔEH, between the salt and the free base was calculated and plotted against experimentally derived gas‐phase proton affinities. The correlation was very good for each of the substituent categories listed. All of the energies and proton affinities were then plotted together on the same graph. The result was an excellent correlation with r = 0.97. The linear equation for gas phase proton affinity, PAB = 28.51 + 435.45ΔEH kcal/mole, was derived from this plot and was used to calculate proton affinities for all of the thirty‐one compounds used in this study as well as for a series of dicyanopyridines for which values of proton affinity are not available at this time.
Reactions of 3‐isopropyl‐, 3‐isopropenyl‐, and 3‐acetyltropolone methyl ethers with guanidines. Synthesis of 9H‐cyclohepta[d]pyrimidin‐9‐ones and cycloheptimidazoles
Authors: Nimura Ryuko , Ishida Noritoshi , Imafuku Kimiaki 
Published: March 2009

Abstract3‐Isopropyl‐ and 3‐isopropenyltropolone methyl ethers reacted with guanidine, 1‐methylguanidine, and 1,1‐dimethylguanidine to afford the corresponding 4‐isopropyl‐ and 4‐isopropenylcycloheptimidazoles 4a‐f, respectively. The reactions of 3‐acetyl‐2‐methoxytropones 2c‐e with guanidines afforded 4‐methyl‐9H‐cyclohepta[d]pyrimidin‐9‐ones 8a‐i, while the reactions of 7‐acetyl‐2‐methoxytropones 3c,d produced 4‐acetylcycloheptimidazoles 4g‐1. From these reactions, several minor products were also isolated.
A conformational analysis of the six isomers of thiobispyridine
Authors: Dunne Simon J. , Summers Lindsay A. , Von Nagy‐Felsobuki Ellak I. 
Published: March 2009

AbstractThe conformational behaviour of the six isomers of thiobispyridine has been investigated using ab initio STO‐3G*//rigid‐roto, STO‐3G*//STO‐3G* and 6–31G**//STO‐3G* molecular orbital models. The analysis reveals both the importance of optimising critical structure parameters and the basis set dependence of calculated rotational barrier heights. The most reliable model (6–31G**//STO‐3G*) clearly indicates that the minimum energy conformers are not planar and that energy barriers between 30–100 kJ mol−1 restrict inter‐conversion to planar structures, thereby preventing conjugation between the p‐electrons of the sulfur atom and the π system of both pyridine rings. From the calculated barrier heights, two mechanisms can be employed to explain conformer interconversion about the CS bond: a disrotatory one‐ring flip or a conrotatory two‐ring flip mechanism. Where comparisons can be made (eg. 2,2′‐thiobispyridine), dipole moment calculations are shown to be in good agreement with experiment. Finally, of the six isomers, appropriately substituted 2,2′, 2,3′‐ and 2,4′‐thiobispyridines are most prone to a Smiles rearrangment.
Synthesis and characterization of 7,16‐dinicotinoyl‐ and 7,16‐diisonicotinoyltetraaza[14]annulene and their nickel(II) and copper(II) complexes
Authors: Sakata Kazunori , Itoh Masaaki 
Published: March 2009

AbstractThe reaction of tetraaza[14]annulene and its complexes with nicotinoyl chloride hydrochloride and/or isonicotinoyl chloride hydrochloride produced the 7,16‐dinicotinoylated and/or 7,16‐diisonicotinoylated corresponding products in satisfactory yields. The mass spectra reveal the molecular ion peaks due to the 7,16‐diacylated products. A strong ir band which is correlated with a C = 0 stretching mode is freshly observed in the 1635–1670 cm−1 region upon the acylation. The electronic spectra for the complexes hardly change upon the acylation, but those for the ligands change slightly. The olefinic proton signals at the 7‐ and 16‐positions disappear on the acylation in 1H‐nmr spectra and the substituted pyridine proton signals are newly observed. The proton nmr results are consistent with those of the carbon‐13 nmr. The spin Hamiltonian parameters for the acylated copper(II) complexes are comparable with those for the copper(II) complex which is not acylated. The copper(II) complexes assume the square‐planar coordinations with an unpaired electron in the dx2−y2 orbital.
Syntheses of 2‐acetyl‐3‐hydroxy‐1‐n‐propylpyrrole from isomaltol and 1‐n‐alkyl‐3‐hydroxy‐2‐methyl‐4‐pyridones from maltol
Authors: Bartulin J. , Belmar J. , Gallardo H. , Leon G. 
Published: March 2009

Abstract2‐Acetyl‐3‐hydroxyfuran (2) reacts with n‐propylamine affording 2‐acetyl‐3‐hydroxy‐1‐n‐propylpyrrole (3) in 63% yield. The transformation of 2‐methyl‐3‐hydroxy‐4‐pyrone (4) into 1‐n‐alkyl‐3‐hydroxy‐2‐methyl‐4‐pyridones is achieved by benzylation of the 3‐hydroxyl group whereupon the product reacts with ammonia and the corresponding pyridone is obtained. The pyridone is alkylated with alkyl bromides and after hydrobromic acid in acetic acid cleavage of the 3‐position ether function, 1‐n‐alkyl‐3‐hydroxy‐2‐methyl‐4‐pyridones are obtained in 48% overall yield.
Nitroimidazoles. IX. Synthesis of 2‐acetyl‐1‐methyl‐5‐nitroimidazole
Authors: Shafiee A. , Pirouzzadeh B. , Ghasemian F. , Parang K. 
Published: March 2009

AbstractManganese dioxide oxidation of 2‐hydroxymethyl‐1‐methyl‐5‐nitroimidazole (6) gave 1‐methyl‐5‐nitroimidazole‐2‐carboxaldehyde (7) in high yield. Reaction of diazomethane with 7 afforded the title compound 1 in low yield. Treatment of ethyl acid malonate with two equivalents of isopropylmagnesium bromide in THF and subsequent addition to 1‐methyl‐5‐nitroimidazole‐2‐carbonylimidazolide (12) yielded ethyl (1‐methyl‐5‐nitroimidazole‐2‐carbonyl)acetate (10) in 70% yield. Hydrolysis and decarboxylation of compound 10 gave the desired compound 1 in 97% yield.
Synthesis of 3‐(β‐D‐ribofuranosyl)pyrazolo[3,2‐i]‐purine derivatives and their cytotoxic activities
Authors: Hamamichi Norimitsu , Miyasaka Tadashi 
Published: March 2009

Abstract9‐Amino‐3‐(β‐D‐ribofuranosyl)pyrazolo[3,2‐i|purine (6) has been prepared from a fully protected 3‐(β‐D‐ribofuranosyl)pyrazolo[3,2‐i]purine (2) and the 9‐bromo substituted derivative 3 by nitration, followed by reduction. Reaction of 9‐bromo‐3‐(β‐D‐ribofuranosyl)pyrazolo[3,2‐i)purine (1b) with alkali gave the (pyrazol‐3‐yl)imidazole derivative, followed by diazocyclization with sodium nitrate to give 9‐bromo‐3‐(β‐D‐ribofuran‐osyl)imidazolo[4,5‐d]pyrazolo[2,3‐c][1,2,3]triazine (10) after deacetylation. Compounds 6 and 10 exhibited cytotoxic activity against leukemia cells.
α‐pyrones. III Synthesis of 5,6‐dihydro‐1H‐benzo[c]‐quinolizin‐1‐ones from 6‐(2‐nitrostyryl)‐2H‐pyran‐2‐ones
Authors: Gelmi Maria Luisa , Pocar Donate 
Published: March 2009

AbstractThe 6‐(2‐nitrostyryl)‐2H‐pyran‐2‐ones 1 were reduced with hydrogen over Pd/C at room temperature and atmospheric pressure giving the 2‐benzoylamino‐4‐(1,2,3,4‐tetrahydro‐2‐quinolinylidene‐2‐pentenedioic acid derivatives 2 which were converted, without isolation, into the 5,6‐dihydro‐1H‐benzo[c]quinolizin‐1‐ones 4 in refluxing acetic anhydride. When α‐aminoacids 2 were treated with acetic anhydride at room temperature oxazolones 3 were isolated, while by heating quinolizines 4 were found. Compounds 3 were transformed into 4 in refluxing acetic acid or anhydride.
Synthesis of some new thieno[3,4‐d]pyrimidines and their C‐nucleosides
Authors: Patil Shirish A. , Otter Brian A. , Klein Robert S. 
Published: March 2009

AbstractThe synthesis of several new thieno[3,4‐d]pyrimidine C‐nucleosides 5‐8 is described. The known 5‐ribosyl‐ated methyl 4‐(formylamino)thiophene‐3‐carboxylate key intermediate 20 was obtained as a mixture of anomers in significantly improved yield by condensation of the sugar 15 with methyl 4‐(formylamino)thio‐phene‐3‐carboxylate 19 in nitromethane at 60° in the presence of stannic chloride. Attempts to prepare the C‐7 ribosylated compound 21β by direct condensation of the bicyclic base 10 with 15 gave instead the N‐1 ribosylated nucleoside 16. The synthesis of the corresponding and previously unknown thieno[3,4‐d]pyrimi‐dine bases 12 and 13 is described along with stability studies on the 4‐methylthio derivative 12. Preliminary biological studies indicate that adenosine analogue 7 is a potent growth inhibitor of several mammalian tumor cell lines.
One step synthesis of dihydropyrrolo[3,2‐e]indoles from 1,4‐cyclohexanedione
Authors: Lash Timothy D. , Bellettini John R. , Voiles Steven J. 
Published: March 2009

AbstractCondensation of phenylhydrazones 1a‐c with 1,4‐cyclohexanedione in the presence of zinc dust, sodium acetate and acetic acid gave the 4,5‐dihydropyrrolo[3,2‐e]indoles 7a‐c. Oxidation of 7a with DDQ afforded the fully aromatic pyrroloindole 16.
Direct bromination of dithieno[3,4‐b:3′,4′‐d]pyridine and dithieno[2,3‐b:3′,2′‐d]pyridine
Authors: Szabó Kálmán J. , Gronowitz Salo , Hassan Mohamed A. 
Published: March 2009

AbstractBromination of dithieno[3,4‐b:3′,4′‐d]pyridine (1) and dithieno[2,3‐b:3′,2′‐d]pyridine (2) has been studied. Disubstitution occurred at both positions of the C ring. The substitution pattern is found to be similar to that of the nitration reaction. The structures of bromo derivatives were established by 1H and 13C nmr spectroscopy.
Synthesis of bicyclic 1,3,5‐triazine‐2,4(3H)‐diones: Reaction of amidines with diphenyl iminodicarboxylate
Authors: Usui Hiroyuki , Watanabe Yoshifumi , Kanao Munefumi 
Published: March 2009

AbstractThe preparation of bicyclic 1,3,5‐triazine‐2,4(3H)‐diones 3 has been investigated. Diphenyl iminodicarboxylate (2) reacted smoothly with cyclic amidines to give bicyclic triazinediones in good yields.
Synthesis of pyrazolo[1,5‐a][4,1]benzoxazepines via intramolecular nitrilimine cycloaddition
Authors: Garanti Luisa , Zecchi Gaetano , Bruché Luca 
Published: March 2009

AbstractA synthetic route to the title compounds is described, which involves as the key step an intramolecular cycloaddition of properly functionalized nitrilimines.
On the regiochemistry of the methylphenylcyclopropenone dimer. A reinvestigation
Authors: Cunha Silvio , Kascheres Albert 
Published: March 2009

AbstractThe regiochemistry of the previously reported dimer of methyhlphenylcyclopropenone is corrected through analysis of the long‐range 1H, 13C correlated (COLOC) 2D nmr spectrum.
Oxo‐ and imino‐functionalized 1,2‐oxazetidines. An overview
Authors: Moderhack Dietrich 
Published: March 2009

AbstractThis review article describes syntheses and reactions of 1,2‐oxazetidines that have an oxo or (substituted) imino group attached to either C‐3 or C‐4. The rare case of a bifunctional derivative is also treated. In a final chapter, spectroscopic properties are surveyed.
Facile synthesis of 5,6,7,8‐tetrahydropyrido[2,1‐b]purin‐10‐one
Authors: Kuroda Takeshi , Suzuki Fumio 
Published: March 2009

AbstractA convenient synthesis of a new heterocycle, 5,6,7,8‐tetrahydropyrido[2,1‐b]purin‐10‐one 1 was described. 4‐Amino‐N‐(5‐chloropentanoyl)‐5‐imidazolecarboxamide 3a was successively cyclized to 1 with polyphosphoric acid at 150°. Methylation of 1 under basic condition proceeded selectively at N‐1 to afford 6 as the sole product.
The reaction of pyrroles with trimethylhalosilanes‐dialkyl sulfoxides
Authors: Bellesia Franco , Ghelfi Franco , Grandi Romano , Pagnoni Ugo Maria , Pinetti Adriano 
Published: March 2009

AbstractPyrroles are powerful nucleophiles in the reaction with dialkyl sulfoxides and trimethylchlorosilane (TMCS) or trimethylbromosilane (TMBS), affording sulfonium salts or halo derivatives, generally in good yields.
Conformational study on indoline compounds. Structures of 2‐phenyl‐3‐arylimino‐3H‐indole 1‐Oxide, 1,2‐dihydro‐2‐phenyl‐2‐benzyl‐ and 2‐tert‐Butyl‐3‐phenylimino‐3H‐indole 1‐oxyls
Authors: Rizzoli Corrado , Sgarabotto Paolo , Ugozzoli Franco , Carloni Patricia , Damiani Elisabetta , Greci Lucedio , Stipa Pierluigi 
Published: March 2009

AbstractReacting 1‐hydroxy‐2‐phenylindole with nitrosobenzene, 2‐phenyl‐3‐phenylimino‐3H‐indole 1‐oxide (1) is produced in only one of the two possible diastereomers. The latter reacts with tert‐butylmagnesium chloride and benzylmagnesium chloride giving, after oxidation, the corresponding aminoxyls which show the same configuration of the phenylimino group at C‐3 as in 1. This has been demonstrated by means of nmr spectros‐copy and X‐ray crystal structure and represents an unexpected stereospecific reaction.
Acetylene chemistry. Part 31. Imidazoquinazolinones derived from the reaction products of 2,4‐dichloroquinazoline and acetylenic amines
Authors: Reisch Johannes , Usifoh Cyril 
Published: March 2009

AbstractThe reaction of 2,4‐dichloroquinazolines with acetylenic amines afforded 2‐chloro‐4‐(1,1‐disubstituted‐N‐prop‐2‐inyl)quinazolines which on boiling in formic acid yeilded the corresponding imidazoquinazolones.
Diazepines and naphthyridines from the rearrangement of thienoindolizidinone oximes
Authors: Marchalin Stefan , Decroix Bernard 
Published: March 2009

AbstractThienoindolizidinone oximes previously reported [1] were treated with polyphosphoric acid and led to thienopyrrolidinodiazepines or thienonaphthyridines. The rearrangement depends on the structural form of the starting oxime and the results obtained are discussed.
A novel practical synthesis of pyrrolo[1,2‐a]thieno[2,3‐e][1,4]diazepines
Authors: Daich Abdelali , Morel Jean , Decroix Bernard 
Published: March 2009

AbstractIn an investigation of new heterocyclic systems, a novel way to obtain pyrrolo[1,2‐a]thieno[2,3‐e][1,4]diazepine 8 was effected by ring closure to the appropriate nitroaldehyde compound which was synthesized in five steps from 3‐bromomethyl‐2‐nitrothiophene 1.
Stereospecific synthesis of the (3aα,11α,12aα)‐decahydrobenzo[a]pyrrolo[3,2‐g]quinolizine ring system
Authors: Clark Robin D. , Nelson Janis T. , Repke David B. 
Published: March 2009

AbstractA stereospecific synthesis of racemic (3aα,11bα,12aβ)‐1,2,3,3a,4,6,7,11b,12,12a‐decahydro‐9‐methoxy‐1‐(methylsulfonyl)benzo[α]pyrrolo[3,2‐g]quinolizine (2) is reported. Cyclocondensation of lithiated pyrrolecarboxamide 5 and dihydroisoquinoline 6 afforded the key tetracyclic intermediate 7. Hydrogenation of 7 gave the 3aα,11bα,12aα‐isomer 9 which was subsequently converted to 2.
Studies on pyrazines. 26. Synthesis of 2,4‐diamino‐6‐methylpteridine 5‐oxide and the inertness of the 6‐methyl‐group functionalization
Authors: Sato Nobuhiro , Suzuki Hiroko 
Published: March 2009

AbstractSynthesis of 2,4‐diamino‐6‐methylpteridine 5‐oxide was achieved in a five‐step sequence of reaction starting from 5‐methylpyrazinecarboxamide. Several attempts to introduce functionality into the 6‐methyl group are described.
N‐1 Substituted ethyl 4‐pyrazolecarboxylates: Synthesis and spectroscopic investigations
Authors: Holzer Wolfgang , Seiringer Gertrud 
Published: March 2009

AbstractThe synthesis of various N‐1 substituted ethyl 4‐pyrazolecarboxylates via reaction of ethyl 2‐formyl‐3‐oxo‐propionate (= ethoxycarbonylmalondialdehyde) with appropriately substituted hydrazines is described. Moreover, detailed nmr‐spectroscopic investigations with the title compounds are presented.
Investigation of isothiocyanate addition to alkylidene derivatives of malononitrile and cyanoacetic acid esters
Authors: Hehemann David G. , Winnik Witold 
Published: March 2009

AbstractAddition of arylisothiocyanates to active methylene compounds leads to a variety of compounds depending on the structure of the starting material and conditions used to conduct the addition. Addition of arylisothiocyanate to 1c leads to a pyrido[2,3‐d]pyrimidine resulting from addition of a second mole of cyanate to the initial adduct. Addition of arylisothiocyanate to 1b led to a mixture of pyridine and thiopyran adducts, while addition to 1a led to open chain structures.
Synthesis of some benzofuronaphthyridines and benzofuronaphthyridine derivatives
Authors: Chen Jian‐Long , Steglich Wolfgang 
Published: March 2009

AbstractThe new benzofuro[2,3‐b]naphthyridine ring system was prepared. 2,4‐Dichloro‐3‐(o‐methoxyphenyl)naphthyridines 3a and 3b were obtained by chlorination of hydroxynaphthyridinones 2a and 2b. Demethylation followed by cyclization of 3a and 3b afforded 11‐chlorobenzofuro[2,3‐b]naphthyridines 4a and 4b. Hydrogenolysis of these 11‐chlorobenzofuronaphthyridines gave the parent benzofuro[2,3‐b]naphthyridines 5a and 5b. The analog 4b was also converted to 11‐methoxybenzofuro[2,3‐b][1,8]naphthyridine (6).
Hydrogen bonding, protonation and twisting in the singlet excited state of some 2‐(4‐Aminophenyl)pyrido‐oxa‐, ‐thia‐, and ‐imidazoles
Authors: Fasani E. , Albini A. , Savarino P. , Viscardi G. , Barni E. 
Published: March 2009

AbstractThe absorption and fluorescence characteristics of 2‐(4‐aminophenyl)pyrido[3,2‐d]oxazole (1), of its thiazole 2 and imidazole 3 analogues, as well as of the corresponding pyrido[3,4‐d]imidazole 4 have been examined. S1 is a planar ππ* ICT state, similarly to p‐electron‐withdrawing substituted anilines. In the protonated form, the chromophore is the heterocyclic moiety. With compounds 3 and 4 in alcohols, hydrogen bonding depending on proton donating and accepting properties of the medium determines the fluorescence. In this case, a red‐shifted emission attributed to a twisted TICT state is also observed.
13C NMR Analysis of some 4‐hydroxy‐2H‐1,2‐benzothiazine 1,1‐dioxides
Authors: Schapira Celia B. , Perillo Isabel A. 
Published: March 2009

AbstractThe 13C nmr spectra of some 4‐hydroxy‐2H‐1,2‐benzothiazine 1,1‐dioxides I have been recorded and analyzed. Spectroscopic assignments were made on the basis of chemical shift theory, APT and fully coupled 13C nmr spectra. Spectral data support the enolic structure of these compounds.
Studies on the chemistry of thienoanellated O,N‐ and S,N‐containing heterocycles. 3. Synthesis of tricyclic thieno[2,3‐b][1,4]thiazines via nucleophilic substitution of activated precursors
Authors: Erker Thomas 
Published: March 2009

AbstractStarting from thieno[2,3][1,4‐b]thiazine 1 new synthetic pathways to the tricyclic compounds 5, 12, 13, 14, 20 and the tetracyclic ring system 19 are described. Under mild reaction conditions some intermediates can be isolated. Reaction of 8 with several amines leads to the amidines 15–18.
Conversion of 1,3‐thiazolidine and its sulfoxide to dihydro‐1,4‐thiazine
Authors: Lee Wha Suk , Nam Kee Dal , Hahn Hoh‐Gyu , Mah He Duck 
Published: March 2009

AbstractTwo methods for constructing dihydro‐1,4‐thiazine 4 were described. 1,3‐Thiazolidines 5 were converted to dihydro‐1,4‐thiazines 4 by chlorinolysis through the unisolable chlorosulfonium salt 10 and sulfenyl chloride 11. Oxidation of the sulfides 5 gave a mixture of pairs of diasteromers 6. In the presence of acid catalyst, both sulfoxides were converted to dihydrothiazine 4 through sulfenic acid 22. In this reaction the stepwise ring opening involving carbocation 23 seems more probable. The structures of 4 were proven by the independent synthesis involving 3‐bromo‐2‐oxobutanoic acid derivatives.
The reactions of benzofuroxan with carbonyl compounds on the surface of solid catalysts
Authors: Takabatake Tohru , Hasegawa Yumiko , Hasegawa Minoru 
Published: March 2009

AbstractThe cyclocondensations of benzofuroxan 1a with carbonyl compounds were smoothly and efficiently carried out by the adsorption of the components on the surface of silica gel or a molecular sieve to form a 2,3‐disubstituted quinoxaline 1,4‐dioxide. When the reactions using a molecular sieve 3A (powder) were carried out at 90°, the actual reaction times were reduced to 0.5‐2 hours. Although Duerckheimer has reported the isolation of only the 7‐substituted quinoxaline 1,4‐dioxide when 5‐methoxybenzofuroxan 1e was allowed to react with ethyl acetoacetate 2j, it produced only the 6‐methoxy isomer as the reaction product by our method. 5‐Carboxybenzofuroxan 1f did not react with the carbonyl compound.
Synthesis of some 5H,12H‐[1]benzoxepino[4,3‐b]indol‐6‐ones. A new heterocyclic ring system
Authors: Chetoni Fabio , Da Settimo Federico , Marini Anna Maria , Primofiore Giampaolo 
Published: March 2009

AbstractThe synthesis of the title compounds 5H,12H‐[1]benzoxepino[4,3‐b]indol‐6‐ones 10 was effected by the Fischer indole cyclization of some 2,3‐dihydro‐4‐phenylhydrazono[1]benzoxepin‐5‐ones 9, obtained from the 3,4‐dihydro‐4‐hydroxymethylene[1]benzoxepin‐5(2H)‐ones 7 by the Japp‐Klingemann reaction. The structure of these new heterocyclic compounds was supported by ir, 1H nmr and ms spectral data.