bluuebunny/crossref_metadata_2025 huggingface dataset:
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

The 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

Methylation 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

1′‐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

Total 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

3‐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

The 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

The 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

2‐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

Manganese 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.
Natural product chemistry. Part 154. Biomimetic synthesis of 3,3′‐umbelliferone
Authors: Reisch Johannes , Zappel Johannes
Published: March 2009

3,3′‐Umbelliferone has been synthesized by oxidation in one step reaction from umbelliferone.
Synthesis of 3‐(β‐D‐ribofuranosyl)pyrazolo[3,2‐i]‐purine derivatives and their cytotoxic activities
Authors: Hamamichi Norimitsu , Miyasaka Tadashi
Published: March 2009

9‐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

The 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

The 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

Condensation 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

Bromination 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

The 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

A 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

The 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

This 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

A 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

Pyrroles 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

Reacting 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

The 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

Thienoindolizidinone 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

In 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

A 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

Synthesis 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

The 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

Addition 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

The 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

The 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

The 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

Starting 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

Two 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

The 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

The 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.
Diazines. IX. Metalation of 2‐chloro, 2‐methoxy and 2‐pivaloylaminoquinoxaline
Authors: Turck A. , Ple N. , Tallon V. , Queguiner G.
Published: March 2009

The lithiation of 2‐chloro, 2‐methoxy and 2‐pivaloylaminoquinoxaline was studied. In the case of 2‐chloro and 2‐methoxyquinoxaline the simultaneous formation of dimers could not be avoided. The resulting lithio derivatives were reacted with carbonyl compounds and iodine. Yields in excess of 50% were obtained.
Pyridine and pyrimidine ring syntheses from 4‐(4‐morpholino)‐3‐pentenone and from ethyl 3‐(4‐morpholino)‐2‐butenoate
Authors: Ratemi Elaref S. , Namdev Nivedita , Gibson Martin S.
Published: March 2009

3‐Substituted 2(1H)‐pyridones are produced from reaction of 4‐(4‐morpholino)‐3‐pentenone 1 with each of the following carbon acids: cyanoacetamide, malononitrile, cyanothioacetamide, acetylacetamide, benzoyl‐acetonitrile. Reaction of ethyl 3‐(4‐morpholino)‐2‐butenoate 2 with cyanoacetamide gives the corresponding hydroxypyridone. Pyrimidines are formed by reaction of 1 and of 2 with benzamidine and with S‐benzylthio‐urea; in the last case, the eliminated morpholine displaces the benzylthio group to give the final product.
Pyridazines. LXVIII. Convenient Synthesis of Phenyl (6‐Substituted 3‐Pyridazinyl) Ketones via the Oxidative Decyanation Route
Authors: Heinisch Gottfried , Langer Thierry
Published: March 2009

A convenient approach to aryl 3‐pyridazinyl ketones 4, 7‐10 bearing various O‐, N‐, or C‐substituents at C‐6 of the diazine nucleus via oxidative decyanation of appropriate aryl‐heteroaryl‐acetonitriles is proposed.
Recognition by a new chiral dimethyl‐substituted phenanthrolino‐18‐crown‐6 diester ligand of the enantiomers of various organic ammonium perchlorates
Authors: Wang Tingmin , Bradshaw Jerald S. , Huszthy Peter , Kou Xiaolan , Dalley N. Kent , Izatt Reed M.
Published: March 2009

Two new chiral dimethyl‐substituted phenanthrolino‐18‐crown‐6 diester ligands [(S,S)‐3] and [(S,S)‐4] (see Figure 1) were prepared through the reactions of 1, 10‐phenanthroline‐2,9‐dicarboxylyl dichloride with (S,S)‐dimethyl‐substituted tricthylene glycol and (S,S)‐dimethyl‐substituted benzotricthylene glycol, respectively. The complexation of (S,S)‐3 with the enantiomers of various organic ammonium perchlorates in various solvent systems was studied by 1H nmr spectral techniques and molecular mechanics. The degree of enantiomeric recognition was determined by the difference in the free energy of activation values (ΔΔG‡C) and the difference in log K values for these interactions. The extensive π system in the ligand plays an important role for the strong interaction and recognition. The 1H nmr NOESY spectra and molecular mechanics calculations for the interactions of the new ligand with the organic ammonium salts further proved the existence of a π‐π interaction.
A novel synthesis of pyrido[2,3‐b][1,5]benzodiazepines
Authors: Okamoto Yoshihisa , Kurasawa Yoshihisa , Aotsuka Tomoji
Published: March 2009

A novel and convenient synthesis of the title compounds 4, 5, 11, and 13 is described, involving the ring transformation of 1,5‐benzodiazepine derivatives 1a and 1b with active methylene compounds.
The reaction of aromatic α,β‐unsaturated ketones with 4,5‐diamino‐1,6‐dihydropyrimidin‐6‐ones
Authors: Insuasty Braulio , Ramos MÓNica , Quiroga Jairo , Sanchez Adolfo , Nogueras Manuel , Hanold Norbert , Meier Herbert
Published: March 2009

The reaction of 4,5‐diamino‐1,6‐dihydropyrimidin‐6‐ones 1 with one equivalent of the chalcones 2 leads in an acidic medium to the formation of the 2,4‐diaryl‐2,3,6,7‐tetrahydro‐1H‐pyrimido[4,5‐b][1,4]diazepin‐6‐ones 3a‐m. The structure elucidation of the products is based on detailed nmr investigations including selective 13C[1H] decoupling experiments.
Synthesis and biological activity of novel mitomycin C analogs derived from mitomycin A
Authors: Kuroda Tokuyuki , Hisamura Koji , Matsukuma Ikuo , Osawa Yutaka , Sugaya Toru , Nishikawa Hiroshi , Morimoto Makoto , Ashizawa Tadashi , Nakamizo Nobuhiro , Otsuji Yoshio
Published: March 2009

A variety of mitomycin C analogs were synthesized from mitomycin A and their biological activities were studied. Mitomycin A (1) underwent nucleophilic displacement reactions involving intramolecular hydrogen migrations upon treatment with nitrogen nucleophiles bearing mobile hydrogens, but the mode of hydrogen migration depended on the nature of the nucleophiles. The reaction with alkoxyamines gave compounds 6 and 7 which have the 5H‐6‐alkoxyimino‐4,7‐dione structure in ring A of 1. However, the reaction with hydroxylamine and benzoylhydrazine afforded compounds 11 and 13 which have the 4‐hydroxy‐6‐hydroxyimino‐7‐one structure and the 4‐hydroxy‐6‐hydrazono‐7‐one structure, respectively, in ring A of 1. These products were converted into various types of mitomycin C derivatives by methylation with methyl iodide or dimethyl sulfate. The mechanistic features of these reactions are discussed. The in vitro and in vivo biological activities were tested by using P388 leukemia and Sarcoma 180 tumor cells. Several of the synthesized compounds exhibited better activity than that of mitomycin C.
NMR study on the tautomeric equilibria between the hydrazone imine and diazenyl enamine forms in side chained quinoxalines: Solvent effects and temperature dependence
Authors: Kurasawa Yoshihisa , Ishikura Aiko , Ikeda Kazue , Hosaka Tomoyoshi , Matsumoto Yuko , Takada Atsushi , Kim Ho Sik , Okamoto Yoshihisa
Published: March 2009

The reaction of 7‐chloro‐4‐ethoxycarbonylmethylene‐4,5‐dihydro‐1,2,4‐triazolo[4,3‐a]quinoxaline 6 with 4‐ethoxycarbonyl‐1‐methyl‐1H‐pyrazole‐5‐diazonium chloride or 4‐cyano‐1,3‐dimethyl‐1H‐pyrazole‐5‐diazonium chloride gave 7‐chloro‐4‐[α‐(4‐ethoxycarbonyl‐1‐methyl‐1H‐pyrazol‐5‐ylhydrazono)‐ethoxycarbonylmethyl]‐1,2,4‐triazolo[4,3‐a]quinoxaline 8a or 7‐chloro‐4‐[α‐(4‐cyano‐1,3‐dimethyl‐1H‐pyrazol‐5‐ylhydrazono)ethoxycarbonylmethyl]‐1,2,4‐triazolo[4,3‐a]quinoxaline 8b, respectively, while the reaction of 7‐chloro‐4‐ethoxycarbonylmethylene‐4,5‐dihydrotetrazolo[1,5‐a]quinoxaline 7 with 4‐ethoxycarbonyl‐1‐methyl‐1H‐pyrazole‐5‐diazonium chloride or 4‐cyano‐1,3‐dimethyl‐1H‐pyrazole‐5‐diazomum chloride provided 7‐chloro‐4‐[α‐(4‐ethoxycarbonyl‐1‐methyl‐1H‐pyrazol‐5‐ylhydrazono)ethoxycarbonylmethyl]tetrazolo[1,5‐a]quinoxaline 9a or 7‐chloro‐4‐[α‐(4‐cyano‐1,3‐dimethyl‐1H‐pyrazol‐5‐ylhydrazono)ethoxycarbonylmethyl]tetrazolo[1,5‐a]quinoxaline 9b, respectively. Compounds 8a,b and 9a,b showed the tautomeric equilibria between the hydrazone imine C and diazenyl enamine D forms in dimethyl sulfoxide and/or trifluoroacetic acid, and the effects of solvent and temperature on the tautomer ratios of C to D were studied by the nmr measurements in a series of mixed trifluoroacetic acid/dimethyl sulfoxide media (compounds 8a,b and 9a,b) and at various temperatures (compounds 8a,b).
A simple, efficient, two‐step synthesis of symmetric 2,7‐dialkyl‐1,6‐dioxaspiro[4.4]nonanes
Authors: Ballini Roberto , Bosica Giovanna , Uselli Alessandra
Published: March 2009

A two‐step synthesis of symmetric 2,7‐dialkyl‐1,6‐dioxaspiro[4.4]nonanes has been achieved by double Michael addition of nitromethane with two moles of enones on Amberlyst A21, followed by in situ reduction with sodium borohydride, then spontaneous spiroketalization of the obtained nitrodiol, by the Nef reaction under acidic conditions, affords the title compounds in good yields.
Ring transformations of heterocyclic compounds. IX. Trifluoromethyl Substituted 2‐Amino‐3,4,6‐triarylbenzophenones by Ring Transformation of 2,4,6‐Triarylpyrylium Salts with Trifluoromethylbenzyl Cyanides
Authors: Zimmermann Thomas
Published: March 2009

The preparation of hitherto unknown trifluoromethyl substituted 2‐amino‐3,4,6‐triarylbenzophenones 3 by a 2,5‐[C4+C2] rins transformation of 2,4,6‐triarylpyrylium salts 1 with trifluoromethylbenzyl cyanides 2 in the presence of sodium methanolate in methanol is reported. Spectroscopic data of the benzophenones 3 and the mode of their formation are discussed.
1,3,4,6‐Tetrakis(isopropylthio)thieno[3,4‐c]thiophenium bis(tetrafluoroborate): X‐ray crystal structure of a stable thieno[3,4‐c]thiophene dication
Authors: Tsubouchi Akira , Inoue Hiroo , Yanagi Kazunori
Published: March 2009

The structure of the 1,3,4,6‐tetrakis(isopropylthio)thieno[3,4‐c]thiophene dication (2) prepared from 1,3,4,6‐tetrakis(isopropylthio)thieno[3,4‐c]thiophene (1) by two‐electron oxidation was investigated by X‐ray crystallographic analysis. The results revealed that the positive charges are largely delocalized on the two i‐PrS‐C‐C‐C‐SPr‐i moieties.
Research on nitrogen and sulfur heterocyclic compounds: Synthesis of 10H‐pyrrolo[1,2‐a]thieno[3,4‐e][1,4]‐diazepin‐5(4H)‐one and some derivatives
Authors: Daich Abdelali , Morel Jean , Decroix Bernard
Published: March 2009

The synthesis of 10H‐pyrrolo[1,2‐a]thieno[3,4‐e][1,4]diazepin‐5(4H)‐one (16) and some derivatives are described from methyl 3‐bromomethylthiophene‐4‐carboxylate (5). The key step of these sequences is the intramolecular cyclization of the carbonylazides 12 and 13.
Intramolecular photoreactions of 6‐(ω‐alkenyl)‐4‐methoxy‐2‐pyrones
Authors: Shimo Tetsuro , Matsuzaki Shigeki , Somekawa Kenichi
Published: March 2009

6‐(ω‐Alkenyl)‐2‐pyrones 3a‐c and 8a, b were prepared and the photochemical reactions were investigated. Photosensitized reactions of 3b, c gave intramolecular [2+2]‐cycloadducts 11b, c as tricyclic lactones, site‐and regio‐specifically. They are not frontier‐orbital‐controlled adducts. On the other hand, 3a, 8a, b afforded cyclobutenecarboxylic acids, 10a, 14a, b, respectively. The end‐ester group at the side‐chain is thought not to be effective for the intramolecular phptoaddition.
Substituent effects on the tautomer ratios between the hydrazone imine and diazenyl enamine forms in side‐chained quinoxalines
Authors: Kurasawa Yoshihisa , Hosaka Tomoyoshi , Ikeda Kazue , Matsumoto Yuko , Ishikura Aiko , Takada Atsushi , Kim Ho Sik , Okamoto Yoshihisa
Published: March 2009

The 3‐(arylhydrazono)methyl‐2‐oxo‐1,2‐dihydroquinoxalines 9–11 were synthesized by the reaction of the quinoxalines 6–8 with various p‐substituted benzenediazonium salts. Compounds 9–11 showed the tautomeric equilibria between the hydrazone imine A and diazenyl enamine B forms in dimethyl sulfoxide media. The substituent effect on the tautomer ratios of A to B was studied by the nmr spectroscopy to clarify that the presence of the ester group R2 on the hydrazone carbon and electron‐donating p‐substituent R1 on the side chain benzene ring exhibited a tendency to increase the ratios of the tautomer A.
Facile synthesis of novel spiro[azetidine‐2,4′(1′H)‐isoquinoline‐1′,3′,4(2′H)‐triones]
Authors: Malamas Michael S.
Published: March 2009

A convenient general method for the synthesis of a new heterocycle, spiro[azetidine‐2,4′(1′H)‐iso‐quinoline‐1′,3′,4(2′H)‐trione] is described. The key intermediate 2 was prepared by direct halogenation of position‐4 of acid 3 with thionyl chloride, and subsequent treatment of the generated 4‐Cl, 4‐acetyl chloride 11 with a THF/NH3 solution at low temperature.
A novel synthesis of 6,7,8,9‐tetrahydro‐5H‐dibenzo[c,g]carbazole
Authors: Dimmock J. R. , Pandeya S. N. , Puthucode R. N. , Quail J. W.
Published: March 2009

The synthesis of the title compound from 2‐tetralone and thiosemicarbazide is reported. The structure was obtained by X‐ray crystallography and its evaluation in certain anticonvulsant, cytotoxic and DNA binding screens is described.
The syntheses and NMR spectra of the twelve isomeric thieno[b]fused naphthyridines
Authors: Björk Patrick , Hörnfeldt Anna‐Britta , Gronowitz Salo
Published: March 2009

Through the use of Pd(0)‐catalyzed couplings between 2‐(2‐trimethylstannyl‐3‐pyridyl)‐1,3‐dioxolane, 3‐trimethylstannyl‐2‐pyridine carboxaldehyde, 3‐trimethylstannyl‐4‐pyridine carboxaldehyde and 4‐trimethyl‐stannyl‐3‐pyridine carboxaldehyde with t‐butyl‐N‐(3‐bromo‐2‐thienyl)carbamate, t‐butyl‐N‐(2‐bromo‐3‐thienyl)carbamate and t‐butyl‐N‐(4‐bromo‐3‐thienyl)carbamate in N,N‐dimethylformamide at 100°, using cupric oxide as a coreagent, all twelve isomeric thieno[b]naphthyridines have been synthesized in an one‐pot procedure. A detailed study of the 1H and 13C nmr spectra of these isomers has been undertaken.
Studies on pyrazines. 29. High regioselective synthesis of chloropyrazines from 3‐substituted pyrazine 1‐oxides
Authors: Sato Nobuhiro , Fujii Megumi
Published: March 2009

Reaction of 3‐methoxy‐ or 3‐chloropyrazine 1‐oxides with refluxing phosphoryl chloride in the presence of amine led to a high regioselective formation of 3‐substituted 2‐chloropyrazines. In contrast, the use of chloroacetyl chloride instead of phosphoryl chloride enabled different regioselectivity to yield 6‐substituted 2‐chloropyrazines, particularly 3‐methoxycarbonylpyrazine 1‐oxide was almost exclusively converted into methyl 6‐chloropyrazinecarboxylate under the conditions without the amine.
Total assignment of the 1H and 13C NMR spectra of pyrrolizino‐[3,4,5‐a,b]isoquinoline, benzo[1,2]pyrrolizino[3,4,5‐a,b]isoquinoline and 2‐methylthiopyrrolizino[3,4,5‐a,b]isoquinoline
Authors: Castle Lyle W. , Tominaga Yoshinori , Castle Raymond N.
Published: March 2009

The total 1H and 13C nmr spectral assignments of pyrrolizino[3,4,5‐a,b]isoquinoline, benzo‐[1,2]pyrrolizino[3,4,5‐a,b]isoquinoline and 2‐methylthiopyrrolizino[3,4,5‐a,b]isoquinoline are reported. The concerted use of the COSY, HMQC, HMBC and nOe‐difference experiments is used to generate total assignments of the 1H and 13C nmr spectra.
Synthesis of tetrahydroimidazo[1,5‐b]‐β‐carboline derivatives with complex basic substituents
Authors: De Miguel Pilar , Martín Nazario , Braña Miguel F.
Published: March 2009

Novel tetrahydroimidazo[1,5‐b]‐β‐carbolines derivatives 6 bearing complex basic chains as substituents on the imidic nitrogen have been prepared in a one‐pot reaction. This simple experimental procedure overcomes the direct handle of isocyanates which can be favorably generated “in situ” from carbonyldiimidazole (CDI) and different amines. The stereochemistry of the novel compounds was determined by nmr experiments.
Isoxazolium enolates derived from α,β‐unsaturated and 1,3‐dicarbonyl compounds. The through‐space effect of the enolate moiety on the chemical shift of α‐protons
Authors: Zvilichovsky Gury , Gurvich Vadim
Published: March 2009

The reaction of 4‐phenyl‐3,5‐dihydroxyisoxazole with α,β‐unsaturated cyclic ketones and 1,3‐cyclic diketones was studied. β‐Substituted α,β‐unsaturated ketones give pairs of isomeric isoxazolium enolates. The remarkable influence of the heterocyclic betaine on the proton chemical shifts is discussed. 1,3‐Cyclic diketones reacted spontaneously with 4‐phenyl‐3,5‐dihydroxyisoxazole yielding isoxazolium enolate enols and enol ethers.
New proton‐ionizable macrocyclic compounds containing one and two triazole subcyclic units — synthesis and complexation properties
Authors: Elshani Sadik , Apgar Pete , Wang Shaofen , Wai C. M.
Published: March 2009

A series of new macrocyclic compounds containing one and two proton‐ionizable triazole subcyclic units have been prepared and characterized. These triazolo‐crowns containing benzo, tert‐butylbenzo or cyclohexano lipophilic groups show varying solubilities in chloroform. The bistriazolo‐crowns dissolved in chloroform are highly effective for extraction of lead, mercury, and gold from aqueous solutions.
Reactions of donor‐substituted furans with electrophilic ethylenes
Authors: Mloston Grzegorz , Huisgen Rolf
Published: March 2009

2‐Methoxyfuran and 2‐p‐tolyloxyfuran were attacked at the 5‐position by tetracyanoethylene or the super‐electrophilic 2,2‐bis(trifluoromethyl)ethylene‐1,1‐dicarbonitrile affording (Z)‐3‐cyclopropylacrylic esters, substituted in the 3‐membered ring. Initially formed zwitterions undergo simultaneous opening of the furan and closure of the cyclopropane ring. In the presence of pyridine, 1,3‐prototropy converts the zwitterion to 5‐substitution products of the furans.
Cobalt(I)‐catalyzed cocyclotrimerization of acetylene with 2,6‐dicyanopyridines
Authors: Chelucci Giorgio , Cabras M. Antonietta , Saba A.
Published: March 2009

A procedure of general application to the synthesis of alkyl‐substituted 2‐cyano‐6‐(2‐pyridyl)pyridines from alkylpyridines is outlined.
Direct monobromination of substituted 4‐oxoquinoline‐3‐carboxylic acid derivatives
Authors: Moẑek Irena , Ŝket Boris
Published: March 2009

N‐Bromosaccharin in the presence of pyridinium poly(hydrogen fluoride) can be used for monobromination of ethyl esters of 6‐ and 7‐substituted‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylic acids. The reactions take place at the C6 or C8 positions, depending on the types and positions of the substituents.
Synthesis and NMR studies of thiazolidine‐4‐carboxylic acid derivatives containing a nitro ester function
Authors: Benedini Francesca , Ferrario Francesco , Sala Alberto , Sala Luca , Soresinetti Pier Angelo
Published: March 2009

The preparation of thiazolidine‐4‐carboxylic acid derivatives containing a 2‐nitrooxyethylamine group, potentially active as vasodilators, is reported. Their1H nmr studies carried out to establish the configuration of the C2 stereocenter and the full assignment of their1H and13C nmr spectra, are also reported.
Synthesis of 5H‐[1]benzopyrano[4,3‐b]pyridin‐5‐ones containing an azacannabinoidal structure
Authors: Heber D. , Berghaus Th.
Published: March 2009

Starting from 7‐alkoxy‐4‐aminocoumarins 5,6,8,12, and 13 as key intermediates, this paper describes two different methods for the preparation of azacannabinoidal 5H[1]benzopyrano[4,3‐b]pyridin‐5‐ones 24–27, 38, and 39 containing typical structural requirements for ZNS activity. First, Michael addition of 6 and 8 to the double bonds of alkyl vinyl ketones 14 and 15 resulted in a mixture of tetrahydropyridines 24–27 and fused pyridines 20–23 the latter of which were reduced by sodium cyanoborohydride to give the target compounds 24–27. The second, pyridine ring closure was accomplished by a combination of Vilsmeier acetylation and formylation resulting in fused 4‐chloropyridines 31–33 followed by reduction.
Experimental and computational studies of trifluoromethylation of aromatic amines by the system trifluoroiodomethane‐zinc‐sulfur dioxide
Authors: Strekowski Lucjan , Hojjat Maryam , Patterson Steven E. , Kiselyov Alexander S.
Published: March 2009

Several trifluoromethyl‐substituted aromatic and heteroaromatic amines have been obtained by the reactions of the corresponding amines with the title reagent system. Computational results provide rationalization for the observed regioselectivities and support a mechanism in which the electrophilic trifluoromethyl radicals interact with the aromatic ring at the sites with the greatest electron density of the HOMO orbitals, and then the resultant adducts are oxidized to cations. The products obtained are potential building blocks for a number of heterocyclic systems.
Novel heterocycles derived from 3‐acyloxy‐ and 3‐acetamidoquinuclidines
Authors: Besidsky Yevgeny , Luthman Kristina , Hacksell Uli
Published: March 2009

New quinuclidine derivatives with 3‐spiro annelated oxathioline, furanone, and pyrrolinone heterocycles have been synthesized from 3‐mesyloxy‐, 3‐acetoxy‐, and 3‐acetamidoquinuclidine‐3‐carbonitrile, respectively, by treatment with base. Treatment of 3‐acetamidoquinuclidine‐3‐carbonitrile (3) with potassium hydride resulted in decyanation whereas alkyllithium reagents attacked the cyano group in 3 to produce the corresponding imines. Oxidative cyclization of the N‐benzylated derivative of 3 with palladium acetate gave the tetracyclic compound 5‐acetyl‐1,4‐ethano‐1,2,3,4,5,6‐hexahydrobenzo[c]‐1,5‐naphthyridine.
Reaction of oxalyl and malonyl chloride with 1,1‐dimethyl‐2‐substituted hydrazides
Authors: Sarker S. R. , Stone D. M. , Evain E. J. , Cooley J. H. , Scott B. L. , Willett R. D.
Published: March 2009

Recently we reported the reaction of 1,1‐dimethyl‐4‐substituted semicarbazides with phosgene to occur with formation of several new heterocyclic ring systems. Here we report the reaction of several semicarbazides, thiosemicarbazides and related acyl substituted hydrazides with oxalyl chloride and malonyl chloride. These reactions occur with the formation of heterocyclic products which are oxadiazolinones, imidazolidinetriones, 2‐thioxoimidazolindine‐4,5‐diones, and 2‐thioxo‐1,3‐diazine‐4,6‐diones (2‐thioxopyrimidine‐4,6‐diones).
Structural study of 5‐methoxyfuro[3,2‐e]imidazo[1,2‐c]pyrimidine
Authors: Quijano M. Luisa , Nogueras M. , Sánchez A. , Melgarejo M. , López R. , Jimeno M. Luisa , Low J. N. , Howie R. A. , Ferguson G.
Published: March 2009

The nmr and X‐ray diffraction data of the novel ring system furo[3,2‐e]imidazo[1,2‐c]pyrimidine are reported in this paper. The crystal and molecular structure of this compound (C9H7N3O2·1/2H2O) has been solved at room temperature. Crystals are monoclinic in a space group of P2/n with cell constants a = 9.982(8), b = 13.526(9) and c = 13.981(9) Å, β = 107.44(5)°, V = 1800.9 Å3, Z = 8, Dx = 1.462 Mg·m−3. The structure was solved by full matrix least square refinement giving a final R = 0.054 (Rw = 0.069) for 1263 reflections (I>3.0σ(I)). The compound is essentially planar, existing in two slightly structural different forms, A and B. These are held in pairs with symmetry related molecules by hydrogen bonds formed with two water molecules. Then the dimeric units are stacked parallel to the c axis to form the tridimensional packing.
Synthesis of 3‐alkyl‐8‐substituted‐ and 4‐hydroxy‐8‐substituted‐2,3,4,5‐tetrahydro‐1H‐2‐benzazepines
Authors: Grunewald Gary L. , Dahanukar Vilas H.
Published: March 2009

Based on the Schmidt reaction and an iodolactone ring expansion reaction, two different synthetic routes to substituted 2,3,4,5‐tetrahydro‐1H‐2‐benzazepines were developed. The Schmidt reaction on 2,3‐dihydro‐2H‐1‐naphthalenone (1) gave 3, the product resulting from the alkyl group migration, as the major product instead of the tetrazole 2. This prompted the investigation of the Schmidt reaction on aromatic ketones 8 and 12. The product 9 due to alkyl group migration was the major product of the Schmidt reaction on 2‐methyl‐3,4‐dihydro‐2H‐1‐naphthalenone (8). The β‐keto diester 12 gave a mixture of decarb‐oxylated lactams after the Schmidt reaction. In this case, the lactam 13 resulting from the migration of the aromatic ring dominated over the other lactam 14. When lactam 14 was subjected to nitration, a single regioisomer was produced and transformed to the bromo alcohol 19. The other approach was based on the single pot ring expansion of the iodolactone 22 to the lactam 23 in the presence of methanolic ammonia. The iodolactone 22 was readily prepared from 2‐allylbenzoic acid.
The photochemical reactions of the halogenated N‐benzylanilines. Mechanism of the reactions
Authors: Park Yong‐Tae , Lee Ick‐Hyung , Kim Young‐Hee
Published: March 2009

Several N‐(2‐halobenzyl)anilines and N‐benzyl‐2‐haloanilines have been synthesized and their photochemical reactions studied. Upon irradiation, the aqueous acetonitrile solution of N‐benzyl‐2‐chloroaniline was cyclized and reduced to give phenanthridine, 5,5′,6,6′‐tetrahydro‐6,6′‐biphenanthridyl (THBP), N‐ben‐zylaniline, and bibenzyl. Similar products were produced in the photochemical reactions of other halo‐genated N‐benzylanilines, except iodo‐substituted N‐benzylanilines. No dimer (THBP) was produced from the iodo‐substituted N‐benzylanilines. Both singlet and triplet states are involved in the photochemical reactions of the haloarenes.
Syntheses of 1,5,6‐trimethyl‐2‐aminoimidazo[4,5‐b]pyridine and 3,5,6‐trimethyl‐2‐aminoimidazo[4,5‐b]pyridine
Authors: Tanga M. J. , Bupp J. E. , Tochimoto T. K.
Published: March 2009

Two potential mutagens found in food, 1,5,6‐trimethyl‐2‐aminoimidazo[4,5‐b]pyridine and 3,5,6‐trimethyl‐2‐aminoimidazo[4,5‐b]pyridine, are synthesized.
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

Lithiation 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

Selective 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

1,6‐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

The 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.