bluuebunny/crossref_metadata_2025 huggingface dataset:
A new synthesis of dibenzo[b,g][1,5]naphthyridine‐6,12(5H,1H)dione (epindolidione)
Authors: Kim C. K. , Maggiulli C. A.
Published: April 2009

A new convenient synthesis of dibenzo[b,g][1,5]naphthyridine‐6,12(5H,11H)dione starting from N‐phenylglycine ethyl ester is described. Ester condensation of N‐phenylglycine ethyl ester with diethyl oxalate followed by reaction with aniline under acid catalysis gave a mixture of diethyl dianilinomaleate and diethyl dianilinofumarate in 54% yield. Upon heating this mixture in a high‐boiling inert solvent, 3‐anilino‐2‐ethoxycarbonyl‐4‐quinolone was obtained in 72% yield. Final ring closure of the quinolone derivative using polyphosphoric acid gave the epindolidione.
The dehydrogenation of the alleged hexahydro‐1,2,4‐triazine‐3,6‐dione
Authors: Schwan Thomas J. , Sanford Timothy J.
Published: April 2009

The dehydrogenation of the alleged hexahydro‐1,2,4‐triazine‐3,6‐dione, recently reassigned the 3‐amino‐2,4‐imidazolidinedione structure, gives upon reaction with bromine water or sodium hypobromite bis[3‐(2,4‐dioxoimidazolidinyl)]diazene instead of tetrahydro‐1,2,4‐triazine‐3,6‐dione as reported previously in the literature.
Acyclopyrimidine C‐nucleosides. Synthesis of acyclopseudoisocytidine and its derivatives
Authors: Chu Chung K.
Published: April 2009

Acyclopseudouridine (IV), acyclopseudoisocytidine (VII), and their 1‐methyl derivatives (V and VIII) were synthesized from 5‐hydroxymethyluracil (I). Acyclopseudouridine (IV) was conveniently prepared from the condensation of 5‐hydroxymethyluracil (I) with ethylene glycol under acidic condition. Compound IV also could be prepared from 5‐chloromethyluracil, however, this procedure was found to be inferior to the direct condensation method. Methylation of IV with dimethylformamide dimethyl acetal gave 1,3‐dimethylacyclopseudouridine (VI) which was subsequently converted to acyclopseudoisocytidine (VII). 1‐Methyl derivatives V and VIII were obtained from the selective methylation of IV and VII, respectively. 5‐Hydroxymethyluracil also reacted with 2‐mercaptoethanol to give the sulfide derivative (IX).
Synthèse d'arylhydroxyspirocétals. Influence du groupe aryle sur la photocyclisation d'arylcétoacétals en série hétérocyclique et osidique
Authors: Bron Pascale , Cottier Louis , Descotes Gérard
Published: April 2009

La photocyclisation d'arylcétoacétals tétrahydropyranniques conduit selon une réaction de type Norrish II à des composés spiranniques. En série acétalique dihydropyrannique, cette réaction entre en compétition avec la réaction de Paterno‐Buchi. En série osidique, la réaction n'est plus stéréosélective comme dans le cas de dérivés méthylés précédemment étudiés; cependant, l'abaissement de la température ralentit Pinterconversion du radical cétalique et conduit principalement aux produits d'hétérocyclisation avec rétention de configuration. Par ailleurs, l'épimérisation acide des spiro C‐1 sucres donne les dérivés trans α ou β.
The stereochemistry of 4‐methyl‐6‐phenyl‐5,6,7,8‐tetrahydro‐4H‐1,3,2,6‐dioxathiazocine 2‐oxides using NMR
Authors: Nishiyama Tomihiro , Kushiyama Masataka , Ikemoto Etsuo , Yamada Fukiko
Published: April 2009

Two isomeric 4‐methyl‐6‐phenyl‐5,6,7,8‐tetrahydro‐4H‐1,3,2,6‐dioxathiazocine 2‐oxides were prepared, and their pmr and cmr spectra were examined. From the aromatic solvent shielding values and the magnitudes of the γ shifts, the title compounds are found to exist in the trans and cis forms in solution.
bis‐alkylsulfonylpyridines
Authors: Woods S. G. , Matyas B. T. , Vinogradoff A. P. , Tong Y. C.
Published: April 2009

Dihalogenated pyridines, some activated with carboxylic, ester or cyano group, were allowed to react with sodium alkylmercaptides. After hydrolysis of the ester or cyano group followed by decarboxylation, bis‐alkylthiopyridines with substituents at 2,3‐, 2,4‐, 2,5‐, 2,6‐ and 3,5‐positions were prepared. These compounds were oxidized to bis‐alkylsulfonylpyridines.
Reaction of 2,3‐diphenylpyrazine 1‐oxides with acetic anhydride
Authors: Ohta Akihiro , Inoue Masami , Yamada Junichi , Yamada Yasuhiko , Kurihara Teruo , Honda Toshihiro
Published: April 2009

Some 2,3‐diphenylpyrazine 1‐oxides were heated with acetic anhydride to give the corresponding 2,3‐di‐acetoxy‐2,3‐dihydro‐5,6‐diphenylpyrazines. By X‐ray diffraction analysis, the configuration of two acetoxyl groups was determined to be trans.
Xanthobilirubic acid and its amides. Synthesis, spectroscopy, and solution structures
Authors: Lightner D. A. , Ma J.‐S. , Adams T. C. , Franklin R. W. , Landen G. L.
Published: April 2009

Xanthobilirubic acid, 5‐[1,5‐didehydro‐3‐ethyl‐4‐methyl‐5‐oxo‐2H‐pyrrol‐2‐ylidene)methyl]‐2,4‐dimethyl‐1H‐pyrrol‐3‐propanoic acid, its methyl ester, amide, N‐methylamide and dimethylamide, and kryptopyrromethenone have been synthesized and characterized spectroscopically. In d6‐DMSO solution all pyrromethenones were monomeric, with lactam and pyrrole N‐Hs H‐bonded to solvent. In deuteriochloroform, the pyrromethenones preferred a dimeric form, with intramolecular H‐bonding between the lactam C = 0 of one unit and the lactam and pyrrole N‐Hs of the second.
Saturated heterocycles. 57. Synthesis of 4‐substituted‐9,10‐dialkoxy‐1,6,7,11b‐tetrahydro‐2H‐pyrimido[6,1‐a]isoquinolin‐2‐ones
Authors: Kóbor Jenö , Fülöp Ferenc , Sami El‐Gharib M. , Bernáth Gábor
Published: April 2009

A large number of 4‐substituted‐9,10‐dialkoxy‐1,6,7,11b‐tetrahydropyrimido[6,1‐a]isoquinolin‐2‐ones were prepared by the reaction of 1‐(ethoxycarbonylmethyl)‐6,7‐dialkoxy‐1,2,3,4‐tetrahydroisoquinolines with iminoethers. Reaction of the corresponding isoquinoline‐1‐acetic acid derivatives with iminoethers led to the formation of N‐acyl‐1,2,3,4‐tetrahydroisoquinolin‐1‐acetamides. In the hydrolysis of the prepared 4‐substituted‐pyrimido[6,1‐a]isoquinolin‐2‐ones, the corresponding N‐acyl‐1,2,3,4‐tetrahydroisoquinolin‐1‐acetamides were obtained. While reduction of the 4‐phenyl derivative resulted in the corresponding 1,3,4,6,7,11b‐hexahydropyrimidinone. The steric structures of the tetrahydro‐ and hexahydropyrimido[6,1‐a]isoquinolines were determined by nmr spectroscopy.
Chemistry of the phenoxathiins and isosterically related heterocycles. XXIX The crystal and molecular structure of 5‐(3′‐hydroxypyridyl‐2′‐thio)‐4‐nitro‐1‐methylimidazole
Authors: Puig‐Torres Salvador , Martin Gary E. , Larson Steven B. , Simonsen Stanley H.
Published: April 2009

Reaction of the dianion of 3‐hydroxypyridine‐2(1H)‐thione with 5‐chloro‐4‐nitro‐1‐methylimidazole in N,N‐dimethylformamide led to the formation of 5‐(3′‐hydroxypyridyl‐2′‐thio)‐4‐nitro‐1‐methylimidazole, which failed to cyclize to the desired pyrid[1,4]oxathiinoimidazole derivative. In an effort to determine why the intermediate phenolate sulfide had failed to cyclize, the crystal structure of the isolated product was determined. The structure refined to R = 0.036.
The compounds related to 3‐(1‐imidazolyl)‐2‐alken‐1‐ones. Preparation and reactions
Authors: Kashima Choji , Tajima Tadakuni , Omote And Yoshimori
Published: April 2009

Compounds related to 3‐(1‐imidazolyl)‐2‐alken‐1‐ones, 3‐(1‐imidazolyl)‐2‐alkenoic acid derivatives and 2‐alken‐1‐ones having heterocycles on the C‐3 carbon were prepared. The reaction of nucleophiles with these compounds was also discussed.
2‐pyridyl‐5‐alkyloxyphenyl‐1,3,4‐thiadiazoles by the action of sulfur on methylpyridines in the presence of alkyloxybenzoylhydrazines
Authors: Mazzone Gioacchino , Puglisi Giovanni , Marchetta Giovanna , Corsaro Antonino
Published: April 2009

Title thiadiazoles were obtained by reaction of sulfur and methylpyridines in the presence of alkyloxybenzoylhydazines. Corresponding oxadiazoles together with symmetrical 2,5‐dialkyloxyphenyl‐1,3,4‐thiadiazoles were also isolated as by‐products. The formation of different reaction products is rationalized.
1,3‐dipolar cycloaddition of methyl 3‐(1‐imidazolyl)acrylate and related compounds
Authors: Kashima Choji , Tsuzuki Atsushi , Tajima Tadakuni
Published: April 2009

The 1,3‐dipolar cycloaddition reaction of 1‐vinylimidazole and β‐(1‐imidazolyl)‐α,β‐unsaturated carboxylic esters with N.α‐diphenylnitrone and acetonitrile oxide was carried out and compared with those of β‐pyrrolidinyl‐ and β‐phenyl‐α,β‐unsaturated carboxylic esters. The imidazolyl moiety bonded to olefinic double bond was suggested to have properties intermediate to pyrrolidinyl and phenyl groups.
Synthesis of 3,5‐disubstituted 1,3,4‐oxadiazole‐2‐thiones as potential fungicidal agents
Authors: Goswami B. N. , Kataky J. C. S. , Baruah J. N. , Nath S. C.
Published: April 2009

Sixteen new 3‐arylaminomethyl‐5‐(2,4‐dichlorophenyl)‐1,3,4‐oxadiazole‐2‐thione and six 3‐alkyl aryl alkyl‐5‐(2,4‐dichlorophenyl)‐1,3,4‐oxadiazole‐2‐thiones were synthesised and characterised by their sharp melting points, elemental analysis, ir, 1H nmr and mass spectra. These substituted oxadiazolethiones were screened for their fungitoxic properties. Most of the compounds showed toxicity against two test organisms, Curvularia verruciformis and Alternaria tenuis. The degree of inhibition ranged from 38‐‐100% for a few compounds.
Combined application of auto‐correlated (COSY) and homonuclear J‐resolved two‐dimensional NMR spectra for the assignment of congested, non‐first order spectra of polycyclic aromatic systems. Assignment of the 1H‐NMR spectrum of benzo[2,3]phenanthro‐[4,5‐bcd]thiophene and an investigation of long range 1H‐1H spin‐coupling constants
Authors: Musmar M. J. , Gampe Robert T. , Martin Gary E. , Layton W. John , Smith Stanford L. , Thompson Robert D. , Iwao Masatomo , Lee Milton L. , Castle Raymond N.
Published: April 2009

Total assignment of the proton nmr spectrum of benzo[2,3]phenanthro[4,5‐bcd]thiophene at 200 MHz is reported. Preliminary identification of the resonances comprising the individual spin Systems was accomplished by the use of auto‐correlated two‐dimensional proton nmr spectroscopy (COSY). Individual assignments were made on the basis of spin‐coupling information which was obtained from the “titled” two‐dimensional J‐resolved (2DJ) proton nmr spectrum of the title compound. Because of the greater resolving power of the latter experiment relative to conventional proton nmr spectroscopy, a number of long range inter‐ring spincouplings were observed. The observation of these long range couplings was crucial to the final assignment of several of the resonances in the spectrum. Resonances due to strong coupling in the 2DJ spectrum were also shown to be a useful means of correlating strongly coupled spins which provides an alternative to the COSY spectrum for this purpose.
Studies on arylhydrazonoisoxazolinethiones. Behaviour of 4‐arylhydrazono‐3‐phenyl‐2‐isoxazoline‐5‐thiones toward hydrazines, grignard reagents and alkylating agents
Authors: Abd Allah Sanaa O. , Elmoghayar Mohamed R. , Abdou Sadek E.
Published: April 2009

The 4‐arylhydrazono‐3‐phenyl‐2‐isoxazoline‐5‐thiones 2 react with hydrazines to yield the 5‐hydrazones 3 and 5. The reaction of 2 with Grignard reagent resulted in addition of the reagent to the thiocarbonyl group to yield 7. Treatment of 2 with diazomethane effected S‐ and N‐methylation beside 1,2,3‐triazole derivative 11 obtained through isomerisation. The potassium salt of 2 react with alkyl halides to yield the S‐alkyl derivatives 12.
Synthesis of perazine
Authors: Owen Terence C.
Published: April 2009

A novel synthesis of perazine (10‐(4‐methylpiperazinyl‐3‐propyl)phenothiazine), likely to be applicable to 10‐dialkylaminopropyl phenothiazines generally, is described.
Hydrolysis of ureas. Kinetics and mechanism of the basic hydrolysis of indole‐1‐carboxamides and (5H‐dibenz[b,f]azepine)‐5‐carboxamide
Authors: Linda Paolo , Ebert Cynthia , Lovrecich Mara , Rubessa Fulvio
Published: April 2009

The hydroxide ion catalyzed hydrolysis of indole‐1‐carboxamide and indole‐1‐(N,N‐dimethyl)carboxamide has been studied in water at 60.0° and [OH−] concentration between 0.3‐‐2.4N. The rate constants of formation of the tetrahedral intermediate are strongly increased by N‐substitution with a heteroaromatic ring in comparison with simple amides. Carbamazepine, (5H‐dibenz[b,f]azepine)‐5‐carboxamide, a potent anticonvulsant drug, is particularly stable under these conditions.
Imidazolyl derivatives of the chroman ring. 1
Authors: Cozzi Paolo , Mongelli Nicola , Pillan Antonio
Published: April 2009

The synthesis of 2‐(1H‐imidazol‐1‐yl)‐2,3‐dihydro‐2H‐1‐benzopyran‐4‐ones (I) through 3‐bromo‐2,3‐dihydro‐4H‐1‐benzopyran‐4‐ones or more conveniently through chroman ring closure from 2‐(1H‐imidazol‐1‐yl)‐2′‐hydroxyacetophenones is described. The ring closure also works well for the pyrazolyl derivatives. Compounds I and the corresponding imidazolylchromanols, ‐chromenes, and ‐chromans derived from the former, were pharmacologically investigated.
Reactions with 1,8‐naphthosultam. Synthesis of [1,2]benzisothiazolo[2,3,4‐cde]benzotriazole 4,4‐dioxide. A new ring system
Authors: Hammouda Hamdy A. , El‐Reedy Ahmed M. , Sharaf Mohie A. F. , Abdel‐Fattah A. M.
Published: April 2009

1,8‐Naphthosultam (I) coupled with arenediazonium salts to give the 4‐arylazo‐ VII, and the 2,4‐bisarylazo‐1,8‐naphthosultams, VIa‐c. On the other hand, coupling of the 4‐substituted 1,8‐naphthosultams afforded the 2‐phenylazo derivatives, IIa,b. Reduction of IIa,b gave the 2‐amino compounds IVa,b, which reacted with nitrous acid to give the [1,2]benzisothiazolo[2,3,4‐cde]benzotriazoles, Va,b, establishing thus a new ring system. The nitro analogue Vc was also synthesized.
Thiophene analogues of carcinogenic polycyclic hydrocarbons. Elbs pyrolysis of various aroylmethylbenzo[b]thiophenes
Authors: Croisy Alain , Mispelter Joël , Lhoste Jean‐Marc , Zajdela François , Jacquignon Pierre
Published: April 2009

The synthesis of benzonaphthothiophenes 9 and 10 and of benzophenanthrothiophenes 14–17 through Elbs cyclodehydration of ortho‐methylated aroylbenzo[b]thiophenes is described. The occurrence of a rearrangement of the thiophene ring in the course of the cyclization is discussed as well as the influence of the temperature on a concurrent cyclodehydration process. Several of these poly‐condensed thiophenes were found carcinogenic in mice.
A facile synthesis of 8‐(β‐D‐ribofuranosyl)‐4‐thioxo‐3H‐pyrazolo[1,5‐a]‐1,3,5‐triazine and its α‐anomer
Authors: Chu Chung K.
Published: April 2009

A versatile intermediate 2 for C‐nucleoside synthesis was treated with thiosemicarbazide to obtain thiosemicarbazone 6, which was then converted to 3‐aminopyrazol‐2N‐thiocarboxamide derivatives 7 and 8 by the reaction of 6 and sodium ethoxide. 4‐Thioxo‐4H‐pyrazolo[1,5‐a]‐1,3,5‐triazine C‐nucleosides 11 and 12 were obtained by the ring closure reaction of 7 and 8 with triethyl orthoformate. Brief treatment of 11 and 12 with 10% methanolic hydrogen chloride afforded C‐nucleosides 4 and 13, respectively, without anomerization. Identification of compounds 4 and 13 was made on the basis of 1H nmr and uv spectra, as well as chemical conversion to known compounds with established configurations. Model compounds were also synthesized in order to confirm the heterocyclic moieties.
Pyridazinderivate. XIX [1,2]. Massenspektrometrische untersuchung halogensubstituierter trans‐styrylpyridazine
Authors: Allmaier Günter , Heinisch Gottfried
Published: April 2009

Die EI‐Massenspektren von 18 am Carbocyclus durch Fluor, Chlor bzw. Brom substituierten 3‐ bzw. 4‐Styrylpyridazinen werden diskutiert. Die Abhängigkeit der Fragmentierungsmuster von der Position der Stickstoffatome relativ zur Ethenylenbrücke erlaubt die eindeutige Differenzierung zwischen 3‐ und 4‐Pyridazinylverbindungen. Die Massenspektren von 3‐Styrylpyridazinderivaten mit ortho‐ständigem Halogen unterscheiden sich signifikant von denen der meta‐ und para‐Isomeren hinsichtlich der relativen Peakintensitäten der [M‐1]+‐ bzw. [M‐X]+‐ Ionen.
Ring opening reaction of N‐substituted dihydropyrimidines with metal hydride complexes
Authors: Kashima Choji , Shimizu Masao , Katoh Akira , Omote Yoshimori
Published: April 2009

N‐Substituted dihydropyrimidines, 1, 3, and 4, easily afforded N,N′‐disubstituted 2,4‐diaminopentanes 2 in good yield by the ring opening reaction with sodium borohydride. The reaction with lithium aluminum hydride was also examined.
Chemistry of the phenoxathiins and isosterically related heterocycles. XXX. The crystal and molecular structure of 2‐AZA‐phenoxathiin 2‐oxide: Further evidence in support of the relationship between the 13C‐NMR chemical shift of C‐10a resonance and the molecular dihedral angle
Authors: Caldwell S. R. , Turley J. C. , Martin G. E. , Dwiggins C. A. , Hossain M. B. , Mendenhall J. V. , Van Der Helm D.
Published: April 2009

The synthesis of 2‐azaphenoxathiin 2‐oxide (4) and the total assignment of the 13C‐nmr spectrum is described. Facile assignment was obtained from the assigned spectrum of 2‐azaphenoxathiin with additivities obtained from a comparison of 1‐azaphenoxathiin and its N‐oxide. The crystal structure has also been determined from three dimensional X‐ray diffraction data. The compound crystallizes in the monoclinic space group P21/n with a = 17.50(2)Å, b = 7.147(3)Å, c = 16.044(7)Å, β = 110.60(5) and Z = 8. Intensity data were collected at ‐ 135 ± 2°C on an automatic diffractometer using nickel‐filtered CuKα radiation. The structure was solved by direct methods and was refined by least‐squares techniques to give a final R‐value of 0.045 for all 3831 independent reflections.
Electron impact mass spectrometry of some new macrocyclic tetraesters
Authors: Podda Gianni , Maccioni Antonio , Anchisi Carlo , Daolio Sergio , Pelli Beatrice , Traldi Pietro
Published: April 2009

The electron impact mass spectrometric behaviour of a new class of macrocyclic tetraesters is reported and discussed in detail with the aid of linked scans, exact mass measurements and collisionally activated decomposition mass analyzed ion kinetic energy spectra.
Thermolysis and photolysis of some 5‐amino‐4‐methoxycarbonyl‐Δ2‐1,2,3‐triazolines
Authors: Bourgois J. , Mathieu A. , Texier F.
Published: April 2009

Thermolysis of 5‐amino‐4‐methyl‐4‐methoxycarbonyl‐Δ2‐l,2,3‐triazolines leads to amidines and 1‐methoxycarbonyl diazoethane. If the N1 substituent is a tosyl or benzoyl group, the corresponding triazoline is not isolated, the azide addition to the olefin gives directly the thermolysis products at room temperature. Triazoline photolysis leads to amino aziridines which are azomethine ylids.
Studies on imidazole derivatives and related compounds. 3. Regioselective glycosylation of 4‐carbamoylimidazolium‐5‐olate
Authors: Tarumi Y. , Moriguchi K. , Atsumi T.
Published: April 2009

In the synthesis of glycosyl derivatives of 4‐carbamoylimidazolium‐5‐olate (2) by the silyl‐Hilbert‐Johnson method using trimethylsilyl trifluoromethanesulfonate as catalyst, we obtained N‐3 nucleosides 5 as major products and N‐1,N‐bis‐nucleosides 6 as minor ones. The desired N‐1 nucleosides 4 were isolated in only low yields. However, the yields of 4 were improved by adding ca. One equivalent of stannic chloride to the silylated 4‐carbamoylimidazolium‐5‐olate (3). On the basis of nuclear magnetic resonance (13C and 29Si) and ultraviolet spectroscopic studies, we verify the formation of σ‐complexes between the silylated base 3 and the Lewis acid (stannic chloride or trimethylsilyl trifluoromethanesulfonate), and the propose the structures of these complexes and the reaction mechanism.
Spiro‐ and bicyclic azalactams by hydrolysis of α‐chlorinated bicyclic amidines
Authors: Löfås Stefan , Ahlberg Per
Published: April 2009

The synthetic potential of α‐chlorinated bicyclic amidines to form spiro‐ and bicyclic azalactams on hydrolysis has been investigated. Thus, 2a,b, prepared by chlorination of 1a,b with carbon tetrachloride in DMF, were treated with water via hydrolysis of the amidine function and an intramolecular substitution, 2a, afforded the azaspirolactam 6a, and 2b gave the isomers 6b and 6c in the ratio 22:78, respectively. Similarly, α‐chlorinated DBU 3b gave the bicyclic azalactam 10. A high‐yield preparative method for obtaining the bicyclic amidine 1a was worked out on the basis of Reissert's method from 1893, starting from diethylmalonate and α‐bromopropylphthalimide.
On the acylation of 1,3‐benzoxathiole systems
Authors: Bernard Angela Maria , Cocco Maria Teresa , Congiu Cenzo , Plumitallo Antonio
Published: April 2009

The acylation on 1,3‐benzoxathiole systems, as well as the effect of the stoichiometry of the catalyst on the yields of ketones and of breaking products of the OCS bonds is here described.
The reaction of N‐aminophthalimide with isothiocyanates
Authors: Hearn Michael J. , Lucas Laura E.
Published: April 2009

N‐Aminophthalimide (I) reacted in refluxing isopropyl alcohol with a number of isothiocyanates to give the related 1:1 addition products, N‐(3‐substitutedthioureido)phthalimides III. On the other hand, heating I directly with an excess of neat arylisothiocyanates produced the N‐arylphthalimides IV. As shown for IIIa, the 1:1 addition products are conveniently deblocked by the Ing‐Manske procedure to yield the 4‐substituted thiosemicarbazide.
Potential anticonvulsants. VIII. Some hydrazones of indole‐3‐carboxaldehyde
Authors: Popp Frank D.
Published: April 2009

Indole‐3‐carboxaldehyde and some additional aldehydes were condensed with various hydrazines, hydrazides, and related compounds. A number of the products exhibited low levels of anticonvulsant activity.
Efficient synthesis of cytotoxic quinones: 2‐Acetyl‐4H,9H‐naphtho[2,3‐b]furan‐4,9‐dione (6) and (±)‐2‐(1‐hydroxyethyl)‐4H,9H‐naphtho[2,3‐b]furan‐4,9‐dione (7)
Authors: Lopes Cláudio C. , Lopes Rosangela S. C. , Pinto Antonio V. , Costa Paulo R. R.
Published: April 2009

From the ethanol extract of the stem bark of Tabebuia cassinoides (Lam.) DC (Bignoniaceae), Kingston and Rao [1] isolated two new furonaphthoquinones 6 and 7 that showed activity in KB cell culture assay (ED50 1.0 and 2.0 μg/ml, respectively). These values may be significant since lapachol, which has an ED50 value of 4.4 μg/ml in the same assay, showed sufficient in vivo activity to reach clinical trial at the National Cancer Institute of the United States. The syntheses of these compounds (6 and 7) were realized in 36% overall yield starting from furan and phthalic anhydride.
Reaction ofN‐benzyl‐1,1′‐iminobis‐2‐butanols with 70% w/w sulfuric acid
Authors: Hernestam Sven , Stenvall Gillis , Olsson Thomas
Published: April 2009

Treatment of (S:R)‐N‐benzyl‐1,1′‐iminobis‐2‐butanol with 70% w/w sulfuric acid givescis‐ andtrans‐N‐benzyl‐2,6‐diethylmorpholines (15 and 74%, respectively) andN‐alkenyl‐4‐ethyl‐1,2,3,4‐tetrahydroisoquinolines (5%). Hydrogenation of the reaction mixture givescis‐ andtrans‐2,6‐diethylmorpholines andN‐butyl‐4‐ethyl‐1,2,3,4‐tetrahydroisoquinoline. NeitherN‐benzyl‐N‐crotyl‐(2‐hydroxy‐1‐butyl)amine (4) norN‐benzyldicrotylamine (5) are intermediates in the reaction. (S:S)‐N‐Benzyl‐1,1′‐iminobis‐2‐butanol gives 95% ofcis‐N‐benzyl‐2,6‐diethylmorpholine and 1% of thetransisomer.
Aminopyrazoles. V. Structure assignment of 1H‐pyrazol‐3‐and 5‐amines by means of the 1H NMR δ(4‐H)‐values of their exo‐N‐toluenesulfonyl derivatives
Authors: Ege Günter , Franz Hermann
Published: April 2009

From the extent of the low field chemical shift of 4‐H caused by exo‐N‐tosylation of 1‐substituted 1H‐pyrazolamines it is possible to distinguish between the 3‐ and 5‐amino‐isomers. The pyrazole substituent increment system of Tensmeyer and Ainsworth has been extended to 3‐ and 5‐amino, 3‐ and 5‐tosylamino, 1‐benzyl and 1‐tosyl substituents. By comparison of δ(4‐H) values, calculated with the aid of these increments, with measured δ(4‐H) values, a differentiation between 3‐ and 5‐tosylaminopyrazoles but not between 3‐ and 5‐aminopyrazoles can be made.
2‐(3,5‐Diaryl‐Δ4‐1,3,4‐thiadiazolin‐2‐yliden)‐1,3‐dithiole eine neue klasse elektronenreicher olefine
Authors: Krasuski Witold , Regitz Manfred
Published: April 2009

Die Dithiolium‐perchlorate 3a und b lassen sich mit Tributylphosphin glatt in die Phosphonium‐perchlorate 4a und b umwandeln. Ihre Deprotonierung mit Butyllithium liefert die Methylenphosphorane 7 (nicht isoliert), aus denen man durch sukzessive Umsetzung mit den Δ4‐1,3,4‐Thiadiazolium‐perchloraten 5d und e und Triethylamin die elektronenreichen Olefine 9a‐d erhält. Die Olefinsynthese läßt sich auch auf umgekehrtem Wege, d.h. durch Reaktion der Phosphoniumsalze 6a‐c mit den Dithioliumsalzen 3a und b bei sonst gleichen Bedingungen ausführen. Auf diesem Wege wurden die elektronenreichen Olefine 9e‐h erhalten.
Polycondensed nitrogen heterocycles. Part 13. Pyrrolo[3,2‐b]indole by intramolecular nucleophilic substitution reaction in the pyrrole series
Authors: Aiello E. , Dattolo G. , Cirrincione G. , Almerico A. M.
Published: April 2009

An intramolecular nucleophilic substitution in the pyrrole series has been generalized. The behaviour of nitro, chlorine, bromine and iodine as leaving groups towards the nucleophilic amino group was observed. An acid catalyzed mechanism has been proposed.
Investigations into the synthesis of 6‐ethyl‐5‐(4‐pyridinyl)‐2,4‐pyrimidinediamine as a potential antimalarial agent
Authors: Hung Jocelyn , Werbel Leslie M.
Published: April 2009

The synthesis of 6‐ethyl‐5‐(4‐pyridinyl)‐2,4‐pyrimidinediamine (2), the pyridine analog of pyrimethamine, is described. Condensation of 4‐pyridineacetonitrile (3) with methyl propionate afforded α‐(1‐oxopropyl)‐4‐pyridineacetonitrile (4). Treatment with triethyl orthopropionate gave primarily the undesiredN‐alkylated material. However reaction of the crude mixture with guanidine afforded2in low yield. This material was devoid of significant antimalarial activity.
(8,9‐Dihydro‐7H‐imidazo[1,2‐c][1,3]diazepin‐5‐yl)‐cyanamide und homologe imidazo‐bizyklen
Authors: Buschauer A. , Schunack W.
Published: April 2009

Die Reaktion der 2‐(ω‐Aminoalkyl)‐imidazole 4a‐f mit N‐Cyanodiphenyl‐imidocarbonat (7) führt zu den entsprechend hydrierten Imidazo[1,5‐a]imidazolen, Imidazo[1,2‐c][1,3]diazepinen und Imidazo[1,2‐c][1,3]diazocinen (9a‐f), die im Verhalten gegenüber Nucleophilen und in ihren spektroskopischen Eigenschaften den (7,8‐Dihydro‐imidazo[1,2‐c]pyrimidin‐5‐yl)‐cyanamiden (3) [1] vergleichbar sind.
Studies on imidazole derivatives and related compounds. 4. Synthesis of O‐glycosides of 4‐carbamoylimidazolium‐5‐olate
Authors: Tarumi Y. , Takebayashi Y. , Atsumi T.
Published: April 2009

Ribosylation of trimethylsilyl derivative of 1‐(4‐nitrobenzyl)‐5‐carbamoylimidazolium‐4‐olate (5) with 1,2,3,5‐tetra‐O‐acetyl‐β‐D‐ribofuranose in the presence of stannic chloride and trimethylsilyl trifluoromethanesulfonate afforded no 5‐O‐glycosides but N‐1 ribosylated compound (6). However, 5‐O‐riboside (7a) and its orthoamide derivative (8) were given by glycosylation of tri‐n‐butylstannyl derivative of 5 with 2,3,5‐tri‐O‐acetyl‐β‐D‐ribofuranosyl chloride in the presence of silver trifluoromethanesulfonate. This procedure was successfully applied to other sugars and 5‐O‐glucuronide (11), a possible metabolite of 1 in vivo, was obtained as one of the 5‐O‐glycoside derivatives.
Pyrazino[2,3‐c][1,2,6]thiadiazine 2,2‐dioxides. Sulfur dioxide analogs of pteridines
Authors: Goya Pilar , Paez Juan Antonio , Pfleiderer Wolfgang
Published: April 2009

Several pyrazino[2,3‐c][1,2,6]thiadiazine 2,2‐dioxide derivatives have been synthesized for the first time by condensation of suitable 4,5‐diamino‐1,2,6‐thiadiazine 1,1‐dioxides and symmetrical 1,2‐dicarbonyl compounds. Structures of these compounds have been characterized by their elementary analyses, 1H‐nmr and uv spectra as well as their pKa values. The most striking differences between this series and the corresponding pteridines are discussed.
Studies on quinones. XII. Cycloketalization of michael adducts from hydroxyquinones
Authors: Cassis Raúl , Tapia Ricardo , Valderrama Jaime A.
Published: April 2009

The reaction of 2‐hydroxy‐3‐(1‐phenyl‐3‐oxobutyl)‐1,4‐naphthoquinone (1) with either acidic methanol or a mixture of trimethyl orthoformate, methanol and ammonium chloride resulted in the formation of the p‐quinonic cycloketals: trans‐ and cis‐4‐phenyl‐2‐methyl‐2‐methoxy‐3,4‐dihydro‐2H‐naphtho[2,3‐b]pyran‐5,10‐dione (2a,2b). Cyclization of the Michael adducts 6, 10 and 11, which are structurally related to 1, with trimethyl orthoformate‐methanol‐ammonium chloride gave the corresponding p‐quinonic cycloketals 7, 12 and 13. The structures of the regioisomers 2a and 2b are proposed based on the spectral properties of compound 7 and by analysis of its proton nmr spectra.
Reduction of the benzoyl group in substituted 5‐benzoyl‐4,5‐dihydro‐1,2,4‐oxadiazoles
Authors: Alcaide Benito , Escobar Gerardo , Pérez‐Ossorio Rafael , Plumet Joaquin
Published: April 2009

The carbonyl group of substituted 5‐benzoyl‐4,5‐dihydro‐1,2,4‐oxadiazoles can be reduced by lithium aluminium hydride at low temperature without ring opening. Mixtures of the two related diastereoisomeric benzylalcohols are obtained. Configurations were assigned by 1H‐nmr.
Facile preparation of symmetric bilirubins IIIα and XIIIα from IXα
Authors: Ma J.‐S. , Lightner D. A.
Published: April 2009

Improved, simple precedures for synthesis and isolation of symmetrically substituted bilirubin‐XIIIα and bilirubin‐IIIα from the natural pigment, bilirubin‐IXα, are described.
Reactions of 3‐aminotropolone with acyl halides. Formation of 8H‐cyclohept[d]oxazol‐8‐ones
Authors: Imafuku Kimiaki , Furuya Miki , Jin Zhong‐Tian
Published: April 2009

3‐Aminotropolone (1) reacted with acetyl chloride and propionyl chloride to give 2‐methyl‐ and 2‐ethyl‐8H‐cyclohept[d]oxazol‐8‐ones (2a and 2b), respectively. The reactions with benzoyl chloride and phenylacetyl chloride gave N‐acylated and N,O‐diacylated 3‐aminotropolones [(3a and 3b) and (4a and 4b)].
Mechanistic aspects of oxidation ofN‐substituted 5H‐dibenz[c,e]azepines by aldehyde oxidase
Authors: Thomas H. Greg , Ruenitz Peter C.
Published: April 2009

5H‐Dibenz[c,e]azepine (2) and itsN‐ethyl andN‐(2‐ethoxyethyl) analogues3and4were prepared and evaluated as substrates for aldehyde oxidase. Quaternization of2with ethyl iodide furnished3, while4was prepared by lithium aluminum hydride reduction ofN‐(2‐ethoxy)ethyldiphenimide followed by mercuric acetate oxidation of the resultant amine6. The rates of oxidation of2and3were similar, suggesting a lack of selectivity by the enzyme for the respective imine and iminium functional groups in these compounds. The rate of oxidation of3decreased with increasingpH while the extent of “hydration” of this substrate increased over a similarpH range, signifying a preference by the enzyme for3over its carbinolamine equilibrium partner. Experiments with deuterium labelled analogues of2and3indicated that azomethine hydrogen loss from these substrates during enzymatic oxidation was not rate determining. Thus 5H‐dibenz[c,e]azepine‐5,5,7‐d3(7), prepared by lithium aluminum deuteride reduction of diphenimide (5), and itsN‐ethyl analogue8, had respective enzymatic oxidation rates which did not differ from those of their non‐deuterated counterparts.
The Thieno[2,3‐c]pyridine Reissert Compound
Authors: Bass R. J. , Popp F. D. , Kant J.
Published: April 2009

Thieno[2,3‐c]pyridine has been converted to 6‐benzoyl‐ and 6‐carbethoxy‐7‐cyano‐6,7‐dihydrothieno[2,3‐c]‐pyridine. Alkylation, condensation, Michael addition, and cyclo addition reactions of these Reissert type compounds have been carried out.
Synthesis of 5,6‐carbonyldioxyindole, a melanogenic cyclic carbonate ester of 5,6‐dihydroxyindole
Authors: Lutz Wilson B. , Mcnamara Craig R. , Olinger Max R. , Schmidt David F. , Doster Douglas E. , Fiedler Mark D.
Published: April 2009

5,6‐Carbonyldioxyindole (4), a melanogenic derivative of 5,6‐dihydroxyindole (1), was synthesized by a procedure starting with 3,4‐methylenedioxycinnamic acid (5). Compound 4 is a stable crystalline solid which is readily hydrolyzed to 1, a key intermediate on the biosynthetic pathway from tyrosine to melanin.
Synthesis of 3‐[(aryl)‐1,2,4‐oxadiazol‐5‐yl]propionic acids
Authors: Srivastava Rajendra Mohan , Viana Maria Benedita De Assunl̂t́o Borges , Bieber Lothar
Published: April 2009

Seven 3,5‐disubstituted oxadiazole derivatives, 3a‐g, have been prepared by direct condensation of appropriate benzamidoxime with succinic anhydride. Spectroscopic properties, especially uv, ir and mass spectra confirmed the cyclic 1,2,4‐oxadiazole structure. No ring‐opened intermediate or side product could be observed. The 1H‐nmr assignments of the two CH2 groups were unequivocally made by acid‐ and base‐induced shifts.
A novel rearrangement reaction. A single‐step conversion of tetrahydro‐1‐isoquinolinecarboxylic acids into 1‐isoquinolones
Authors: Vaccher Claude , Berthelot Pascal , Debaert Michel , Barbry Didier
Published: April 2009

The preparation of 2‐acyl‐6,7‐dimethoxy‐1,2,3,4‐tetrahydro‐1‐isoquinolinecarboxamides is described. The mixed anhydride of 2‐acyl‐6,7‐dimethoxy‐1,2,3,4‐tetrahydro‐1‐isoquinolinecarboxylic acid with isobutyl chloroformate was reacted with the corresponding hydrazines at — 10, — 15°. Besides those compounds, isoquinolones occur through a new side reaction. The structure of those products was established by13C and1H nmr and mass spectroscopy. A possible mechanism of the reaction is discussed.
Synthesis and antibacterial activity of 1‐(2,4‐dichlorobenzoyl)‐4‐substituted thiosemicarbazides, 1,2,4‐triazoles and their methyl derivatives
Authors: Goswami Birendra N. , Kataky Jiban C. Sarmah , Baruah Jogendra N.
Published: April 2009

A series of 1‐(2,4‐dichlorobenzoyl)thiosemicarbazides, s‐triazoles and their methyl derivatives have been synthesised by condensation of 2,4‐dichlorobenzoyl hydrazine with aryl isothiocyanates. Subsequent ring closure of the substituted thiosemicarbazides yielded the s‐triazoles, and reaction with methyl iodide resulted methyl derivatives. All the compounds were subjected to in vitro testing against two gram‐positive and two gram‐negative bacteria. Antibacterial activity was found to be moderate to good in most of the compounds.
A novel synthesis of precursors to 3‐thienylmalonic acid
Authors: Raynolds Peter W.
Published: April 2009

Methyl 2‐cyano‐2‐(3‐thienyl)acetate can be prepared in 95% yield by treating methyl 2‐cyano‐2‐(3‐tetra‐hydrothienylidene)acetate with sulfuryl chloride, followed by dehydrohalogenation with pyridine. The product can be hydrolyzed to 3‐thienylmalonic acid, a pharmaceutical intermediate.
Reaction of benzofurazan N‐Oxide with 1‐aza‐1,3‐butadienes. Synthesis of a novel class of quinoxaline N,N′‐dioxide imines
Authors: Devi Purabi , Sandhu Jagir S.
Published: April 2009

1‐Aza‐1,3‐butadienes react with benzofurazan N‐oxide (BFO) to give a new class of N,N'‐dioxide imines.
2H‐[1]‐benzotellurinnone‐2 (telluro‐1 coumarine) et dihydro‐3,4‐chalcogéno‐1 coumarines
Authors: Christiaens Léon , Piette Jean‐Louis , Luxen André , Renson Marcel
Published: April 2009

La 2H[1]‐benzotellurinnone‐2 (telluro‐1 coumarine), et des dihydro‐3,4‐ chalcogéno‐1 coumarines ont été synthétisées par cyclisation intramoléculaire de l'acide ou du chlorure d'acide correspondant. Les nouveaux systèmes hétérocycliques sont caractérisés par différentes méthodes physicochimiques: ir, rmn 1H et 13C et spectrométrie de masse.
Halogenated ketenes. 39. A new synthesis for substituted coumarins
Authors: Brady William T. , Shieh C. H.
Published: April 2009

A new general synthesis of substituted coumarins is described. The in situ cycloaddition of chloroketenes with α‐methoxymethylenecyclohexanones yields (4 + 2) cycloaddition products, 3,4‐dihydro‐2‐pyranones. The chlorine atom is reductively removed and methanol is spontaneously eliminated to yield the 5,6,7,8‐tetra‐hydrocoumarins. Dehydrogenation of these compounds results in good yields of the substituted coumarins.
Zur addition von nucleophilen an C(2) heterocyclischer 2‐methylsubstituierter quartärsalze
Authors: Schelz Dieter
Published: April 2009

1‐(4‐Chlorophenyl)‐2‐methyl‐3‐phenylquinoxalinium perchlorate (5) obtained by two different routes, on treating with nucleophiles HX or X− yielded 1,3‐diaryl‐2‐methyl‐2X‐1,2‐dihydroquinoxalines 10. Alkylation of 10e yielded 4‐(4‐chlorophenyl)‐1,3‐dimethyl‐3‐nitromethyl‐2‐phenyl‐3,4‐dihydroquinoxalinium perchlorate (11e). The 1H‐nmr and mass spectra are presented. Diastereoisomerism of the products is discussed.
New route to N‐aryl and N‐heteroaryl derivatives of 4‐hydroxy‐3‐quinolinecarboxamides
Authors: Clémence François , Le Martret Odile , Collard Jeannine
Published: April 2009

The synthesis of N‐aryl and N‐heteroaryl substituted 4‐hydroxy‐3‐quinolinecarboxamides 1 is described. The attack of dianions 12 of N‐aryl substituted acetamides on the C‐4 carbonyl of 4H‐3,1‐benzoxazin‐4‐ones 11 gave rise to ketoamides 13, which smoothly cyclised in the presence of bases to afford quinolinecarboxamides 1. By this method, a large number of 2‐substituted 4‐hydroxyquinolinecarboxamides can be prepared.
Stereochemical studies. 81. Saturated heterocycles. 69. Preparation of methylene‐bridged 3,1‐benzoxazines, 3,1‐benzoxazin‐2‐ones and 3,1‐benzoxazine‐2‐thiones
Authors: Stájer Géza , Szabó Angela E. , Fülöp Ferenc , Bernáth Gábor , Sohár Pál
Published: April 2009

3‐exo‐Aminobicyclo[2.2.1]hept‐5‐ene‐2‐exo‐carboxylic acid and ethyl 3‐endo‐aminobicyclo[2.2.1]heptane‐2‐endo‐carboxylate (6) were reduced with lithium aluminum hydride to the corresponding bicyclic aminoalcohols 3 and 4. These and the saturated endo‐endo and exo‐exo N‐methylaminoalcohols 16 and 22, respectively, were converted to methylene‐bridged tetrahydro‐ (11) and hexahydro‐3,1‐benzoxazin‐2‐ones 12, 17, 23 and 3,1‐benzoxazin‐2‐thiones 13, 14, 18, 24. The exo‐exo 3 and endo‐endo 4 aminoalcohols were cyclized by means of ethyl arylimidates to tricyclic dihydro‐1,3‐oxazines 7a‐d, 8a‐d. The structures were confirmed by ir, 1H and 13C nmr spectroscopy.
Addition des azidosulfates sur le norbornadiène
Authors: Hedayatullah Mir , Hugueny Jean Claude , Guy Alain
Published: April 2009

L'action des azidosulfates d'aryle sur le norbornadiène fournit sélectivement et avec de hauts rendements, les N‐(aroxysulfonyl) aza‐2 bicyclo[3,2,1]octadiènes‐3,6 résultant de l'insertion de l'azote dans le cycle. La structure des nouveaux produits d'expansion du cycle ainsi formés a été établie par dégradation hydrolytique, synthèse indépendante et données spectrales (ir, rmn).
Reactions and rearrangement of 2,4‐quinazolinediones. An efficient simple synthesis of 3‐amino‐1H,3H‐quinazolinedione
Authors: Badawy M. A. , Ibrahim Yehia A. , Kadry Azza M.
Published: April 2009

An efficient synthesis of 3‐amino‐1H,3H‐quinazolinedione by the action of hydrazine on the readily accessible 3‐phenyl‐2,4(1H,3H)‐quinazolinedione and 2‐anilino‐4H‐3,1‐benzoxazin‐4‐one are described.
Le polyphosphate d'éthyle, un réactif de choix pour la synthèse de dérivés du benzo[b]furanne dicarboxylate‐2,3 de méthyle
Authors: Belleney Joël , Vebrel Joël , Cerutti Ernest
Published: April 2009

Ce travail a pour objectif la mise au point d'une méthode rapide et efficace de synthèse de dérivés méthylés du benzo[b]furanne dicarboxylate‐2,3 de méthyle. Nous apportons pour cela des améliorations significatives à la méthode de Koelsch et Whitney [1], notamment grǎce à l'emploi du polyphosphate d'éthyle. Ce réactif se révèle en effet particulièrement bien adapté à la cyclodéshydratation des aryloxy‐2 hydroxy‐3 maléates de méthyle intermédiaires en dérivés benzofuranniques, puisque les rendements dépassent le plus souvent 80%.
Pyrimidines. 21. Novel reactions of 5‐cyano‐1,3‐dimethyluracil with carbon nucleophiles. A facile preparation of certain pyrido[2,3‐d]pyrimidines
Authors: Su Tsann‐Long , Watanabe Kyoichi A.
Published: April 2009

Treatment of 5‐cyano‐1,3‐dimethyluracil (8) with an activated acetonitrile, such as malononitrile, ethyl cyanoacetate or cyanoacetamide, in base afforded 7‐amino‐6‐cyano‐, 7‐amino‐6‐ethoxycarbonyl‐, and 7‐amino‐6‐aminocarbonyl‐1,3‐dimethylpyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione (18b, 18c and 18d, respectively) in high yields. On the other hand, reaction of 8 with acetonitrile in base gave the Michael adduct, 5‐cyano‐6‐cyanomethyl‐5,6‐dihydrouracil (15, R = H), and the hydrated product, 1,3‐dimethyluracil‐5‐carboxamide (9) as the major products, and 7‐amino‐1,3‐dimethylpyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione (18a) in only very low yield. Similar reaction with butanone gave 7‐ethyl‐1,3‐dimethyl‐ and 1,3,6,7‐tetramethylpyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione (10b and 10c) in low yields.

When 8 was treated with diethylmalonate in base, only a small amount of 6‐ethoxycarbonyl‐1,3‐dimethylpyrido[2,3‐d]pyrimidine‐2,4,7(1H,3H,8H)‐trione (19) was obtained together with 1,3‐dimethylpyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione (20) and 18c (also in low yields). Treatment of 8 in ethanolic sodium ethoxide without added carbon nucleophile gave significant amounts (14%) of 20 and a small amount of 18c.
Synthesis of 1H‐pyrazolo[3,4‐e]‐s‐triazolo[3,4‐c]‐as‐triazines, 8H‐pyrazolo[3,4‐e]tetrazolo[5,1‐c]‐as‐triazine and 1,7‐dihydro‐8H‐pyrazolo[3,4‐e]‐as‐triazine derivatives
Authors: Youssef M. S. K. , Hassan Kh. M. , Atta F. M. , Abbady M. S.
Published: April 2009

3‐Hydrazino‐7‐methyl‐5‐phenyl‐5H‐pyrazolo[3,4‐c]‐as‐triazine 1 underwent ring closure and/or condensation reaction with formic acid, acetic acid, acetic anhydride and benzoyl chloride to afford 1H‐pyrazolo‐[3,4‐d]‐s‐triazolo[3,4‐c]‐as‐triazines 2, 5 and 7a and/or N‐acyl derivatives 3, 4 and 6. N‐Acyl derivatives 3 and 6 underwent cyclisation reaction on treatment with phosphoryl chloride to give 5 and 7a. 3‐Methyl‐1‐phenyl‐8‐aryl‐1H‐pyrazolo[3,4‐e]‐s‐triazolo[34,‐c]‐as‐triazines 7 were also prepared by the reaction of the hydrazono derivatives 8 wit thionyl chloride. On treatment of 1 with nitrous acid gave the 8H‐pyrazolo[3,4‐e]tetrazolo‐[5,1‐c]‐as‐triazine 9. Compound 1 underwent ring closure with carbon disulphide or ethyl chloroformate to 1,7‐dihydro‐8H‐pyrazolo[3,4‐e]‐s‐triazolo[3,4‐c]‐as‐triazine derivatives 10 and 12. Reaction of 1 with ethyl acetoacetate or acetylacetone gave 3‐pyrazolo derivatives 13 and 14.
Synthesis of bridgehead nitrogen heterocycles from pyrylium salts and β‐functionalized amines
Authors: Molina P. , Alajarin M. , Lorenzo‐Peña M. , Tárraga A. , Vilaplana M. J.
Published: April 2009

β‐Functionalized primary amines are converted by the 2‐ethoxycarbonyl‐4,6‐diphenylpyrylium cation into the corresponding bicyclic salts 2. The N‐substituted 4,6‐diphenylpyridine‐2‐thiones 6 undergo cyclization to the byciclic compounds 8 by action of methyl iodide.
The reaction of 2‐(3‐sydnonyl)phenylmethanol with sulfonyl chlorides. A one pot conversion to the chloro congener
Authors: Turnbull Kenneth
Published: April 2009

The interesting transformation of 2‐(3‐sydnonylphenylmethanol (1) to its chloro congener 2, in moderate to good yield using sulfonyl chlorides, is described. A mechanism for the transformation is suggested.
Novel 2′‐substituted amino‐3‐methoxy‐16α‐bromo‐17‐oxoestra‐3,5(10)‐dieno[1,2‐b]thiazoles
Authors: Omar A.‐Mohsen M. E. , Aboulwafa Omaima M.
Published: April 2009

A novel series of steroidal[1,2‐b]thiazoles was synthesized by cyclization of several thiourea derivatives with bromine according to Hugerschoff synthesis. The H‐nmr spectral analyses elucidating the structure of the products and the orientation of ring closure are reported.
Synthesis of 6‐halogenated 4H‐1,4‐benzothiazines
Authors: Gupta R. R. , Kumar Rakesh , Gautam R. K.
Published: April 2009

The synthesis of 6‐halogenated 4H‐1,4‐benzothiazines is reported by the condensation and oxidative cyclization of 4‐substituted 2‐aminobenzenethiols (I, R = Cl, Br) with β‐diketones in presence of DMSO. The ir, nmr and mass spectral studies are included. 4‐Substituted 2‐aminobenzenethiols were also prepared by an improved and direct method.
Synthesis and determination of maximum rotatory power of (+)‐(S)‐5‐s‐butyl‐2(1H)‐pyridinone
Authors: Chelucci G. , Marchetti M. , Soccolini F. , Botteghi C.
Published: April 2009

Optically active (S)‐5‐s‐butyl‐2(1H)‐pyridinone (6) is obtained by reaction of 2‐s‐butylacrolein (1) and N‐(carbamylmethyl)pyridinium chloride. The relationship between optical activity and minimum optical purity is determined.
Stereoselective addition of carbamates to unsaturated systems by means of mercury(II) nitrate. Synthesis of saturated nitrogen‐containing heterocycles
Authors: Barluenga J. , Jiménez C. , Nájera C. , Yus M.
Published: April 2009

The aminomercuration of dienes with carbamates and mercury(II) nitrate affords, after in situ demercuration with sodium borohydride, stereoselectively saturated nitrogen‐containing heterocycles. Thus, the corresponding amidomercuration‐demercuration of 1,4‐ or 1,5‐hexadiene, and diallyl ether gives respectively N‐alkoxycarbonyl cis‐2,5‐dimethylpyrrolidines and trans‐3,5‐dimethylmorpholines. From 1,5‐cyclooctadiene 9‐alkoxycarbonyl‐9‐azabicyclo[3.3.1]‐ and [4.2.1]‐nonanes (molar ratio ca. 1:1) are obtained. By amidomercuration‐demercuration of N‐allylurethane cis‐N,N'‐bis(ethoxycarbonyl)‐2,5‐dimethylpiperazine is obtained. The intermolecular amidomercuration of unsaturated systems results stereochemically opposite to the same aminomercuration process.
Reactions of ethyl β‐methoxycrotonate with some α,β‐unsaturated carbonyl compounds. Synthesis of 6‐aroyl‐5‐aryl‐3‐methoxycyclohex‐2‐enones
Authors: Shandala Mowafak Y. , Ayoub Mikdad T. , Kareem Ahmad A.
Published: April 2009

3‐Aryl‐1‐phenyl‐2‐propen‐1‐ones Ia‐h and 1‐aryl‐3‐phenyl‐2‐propen‐1‐ones Ii‐ℓreacted with ethyl β‐methoxy‐crotonate (II) in the presence of sodium hydride in dry THF at 0° for 10 hours to give the corresponding 6‐aroyl‐5‐aryl‐3‐methoxy‐2‐cyclohexen‐1‐ones III. The structures of the products were confirmed by ir, pmr, 13C nmr and uv spectroscopy.
Synthesis of the monomethyl isomers of naphtho[1′,2′:4,5]thieno[2,3‐c]quinoline
Authors: Kudo Hirotaka , Castle Raymond N. , Lee Milton L.
Published: April 2009

The synthesis of naphtho[1′,2′:4,5]thieno[2,3‐c]quinoline (11) and four monomethyl isomers is described.
The structural effects of fluorine substitution in pyridine, pyrimidine, and s‐triazine: An ab initio study
Authors: Boggs James E. , Pang Frank
Published: April 2009

The structures of 2‐fluoropyridine, 3‐fluoropyridine, 4‐fluoropyridine, pentafluoropyridine, 2‐fluoropyrimidine, 5‐fluoropyrimidine, and fluoro‐s‐triazine have been evaluated by the ab initio gradient method with a 4‐21 basis set augmented as needed with polarization functions on nitrogen. The structural effects of fluorination on the parent heterocycle are very similar to the effects of fluorination on benzene studied earlier. The ring angle is enlarged by about 2° at the point of fluorination and the adjacent ring bonds are shortened, much more for an adjacent C‐N than for C‐C. Fluorination of pyridine at the C2 position causes an in‐crease of bond localization in the ring. Rotational constants calculated from the structural parameters corrected with standard offset values are in exceptionally close agreement with experimental constants where these are known.
The synthesis of phenanthrodibenzothiophenes
Authors: Kudo Hirotaka , Tedjamulia Marvin L. , Castle Raymond N. , Lee Milton L.
Published: April 2009

The synthesis of phenanthro[1,2‐c]dibenzothiophene (6), phenanthro[4,3‐c]dibenzothiophene (10), phenanthro[2,1‐a]dibenzothiophene (14), phenanthro[3,4‐a]dibenzothiophene (16), phenanthro[1,2‐a]dibenzothiophene (19), phenanthro[2,1‐b]dibenzothiophene (20), 8‐methylphenanthro[3,2‐a]dibenzothiophene (24), 7‐methylphenanthro[1,2‐a]dibenzothiophene (25), phenanthro[3,4‐a]dibenzothiophene (27), phenanthro[4,3‐a]‐dibenzothiophene (28), 6‐methylphenanthro[2,3‐a]dibenzothiophene (31), and 5‐methylphenanthro[4,3‐a]dibenzothiophene (32) is described.