bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 2,3,7,8‐tetramethoxydibenzotellurophene and its thio and seleno analogues
Authors: Engman Lars
Published: April 2009

The title compounds5were obtained from the reaction of 3,3′,4,4′‐tetramethoxybiphenyl (6) or its 2,2′‐dilithio derivative8with various chalcogen electrophiles (sulfur dichloride, selenium tetrachloride, selenium oxychloride and tellurium tetrachloride).
Ring opening in the amination of 3‐X‐1,2,4‐triazines [1,2]. A 15N study
Authors: Rykowski Andrzej , Van Der Plas Henk C.
Published: April 2009

Evidence, based on 15N‐labelling studies, has been obtained that the amino‐dechlorination of 3‐chloro‐1,2,4‐benzotriazine by potassium amide in liquid ammonia occurs according to an SN(AE)ipso process, while the amino‐dechlorination of 3‐chlorophenanthro[9,10‐e]‐1,2,4‐triazine reacts for more than 90% according to a process involving a ring opening reaction [SN(ANRORC)ipos substitution].
Synthesis and NMR studies of some imidazo[4,5‐d]pyridazine nucleosides
Authors: Gagnier R. Paul , Halat Michael J. , Otter Brian A.
Published: April 2009

Unlike imidazo[4,5‐d]pyridazin‐4(5H)‐one (1a), which undergoes ribosylation at N‐6 in the Vorbruggen procedure for nucleoside synthesis, the 5‐benzyloxymethyl derivative 12 undergoes ribosylation at N‐1 and N‐3 to give a separable mixture of 14 and 15. Removal of the N‐5 blocking groups from 14 and 15 by treatment with boron trichloride at −78° affords the intermediates 16 and 17, which were debenzoylated to give the 4‐oxo nucleosides 5 and 6. Thiation of 16 and 17, followed by S‐methylation and ammonolysis leads to the 4‐amino nucleosides 2 and 3. The glycosylation sites of these nucleosides were assigned by using a combination of 1H and 13C nmr data, especially measurements of the spin‐lattice relaxation times (T1) of the base protons. Using these techniques, it is shown that a nucleoside previously reported to be 3 is in fact the N‐6 isomer.
Preparation and properties of 4‐nitrosoquinolines
Authors: Demeunynck Martine , Tohme Najat , Lhomme Marie‐France , Lhomme Jean
Published: April 2009

4‐Nitrosoquinoline (2a) and 4‐nitroso‐7‐chloroquinoline (2b) were prepared from the parent hydroxyzines. Their characteristic nmr spectrum were recorded. These highly reactive compounds condense readily with 2,3‐dimethyl‐1,3‐butadiene and with aniline.
Acyclo analogs of formycin a
Authors: Griengl H. , Günzl F.
Published: April 2009

Starting from 7‐chloro‐3‐methyl‐1H‐pyrazolo[4,3‐d]pyrimidine (1) by reaction with methanol/hydrogen chloride, subsequent methylation and reaction with N‐bromosuccinimide 3‐bromomethyl‐7‐methoxy‐1‐methyl‐1H‐pyrazolo[4,3‐d]pyrimidine (6) is prepared. Treatment with ethylene glycol in the presence of potassium carbonate/potassium iodide and subsequent reaction with ethanolic ammonia afforded 7‐amino‐3‐(2‐hydroxyethoxymethyl)‐1‐methyl‐1H‐pyrazolo[4,3‐d]pyrimidine (11) an acyclo analog of formycin A.
Synthèse de dihydro‐4,9 dipyrazolo[1,5‐a:1′,5′‐d]pyrazines
Authors: Lupo Brigitte , Tarrago Georges , Ramdani Abdelkrim
Published: April 2009

La cyclisation intramoléculaire d'halogénométhyl‐5 dipyrazolyl‐1,3′(5′) méthanes diversement substitués a conduit aux dihydro‐4,9 dipyrazolo[1,5‐a:1′,5′‐d]pyrazines correspondantes selon une voie univoque, l'étude de la quaternarisation de ces nouveaux hétérocycles a été réalisée sur certains d'entre eux au moyen de l'iodure de méthyle.
Réaction de l'amino‐2 nitro‐5 phénol et du diamino‐2,5 phénol avec quelques acides et esters α‐cétoniques. Synthèse d'amino‐7 benzoxazines‐1,4 ones‐2
Authors: Le Bris Marie‐Thérèse
Published: April 2009

l'amino‐5 nitro‐2 phénol réagit avec les acides et les esters α‐cétoniques en conduisant, soit à des composés hétérocycliques (benzoxazinone, benzoxazoline), soit à des composés non cyclisés: imines, amides. Le diamino‐2,5 phénol, avec les mêmes réactifs, donne exclusivement les amino‐7 benzoxazines‐1,4 ones‐2 très fluorescentes et stables en solution dans les solvents organiques, à l'exclusion de l'éthanol.
Studies on the synthesis of heterocyclic compounds. XIV. Cleavage of 1,3‐benzoxathioles by magnesium bromide‐acetic anhydride
Authors: Bonsignore Leonardo , Fadda Anna Maria , Loy Giuseppe , Maccioni Anna Maria , Marongiu Enrica , Podda Gianni
Published: April 2009

The cleavage reaction of some 1,3‐benzoxathioles with magnesium bromide and acetic anhydride has been studied. In all the 1,3‐benzoxathioles studied, the opening of the heterocyclic ring occurs first with cleavage of the CO bond and formation of bromides and their corresponding products of hydrolysis. Successively also the cleavage of the CS bond can occur. The competitive electrophilic substitution on the benzene ring becomes appreciable only in the 1,3‐benzoxathioles‐2,2‐disubstituted with sterically demanding groups. The structure of newly prepared compounds has been determined by analytical and spectroscopic data and when possible by comparison with authentic samples.
Studies on the synthesis of heterocyclic compounds. XIII. The synthesis of macrocyclic tetraesters from 1,2‐cyclohexane‐ and 2,3‐butanediols
Authors: Anchisi Carlo , Corda Luciana , Fadda Anna Maria , Maccioni Antonio , Podda Gianni
Published: April 2009

A new series of macrocyclic compounds containing 1,2‐cyclohexanediols and 2,3‐butandiol sub‐unit have been prepared treating the stannolanic and stibolanic derivatives with diacyl chlorides. The structures of the compounds prepared have been determined by elemental analysis and spectroscopic data.
Synthesis of some N‐(4,5,5‐trisubstituted‐Δ2‐1,3,4‐thiadiazolin‐2‐yl)‐N,N′‐dimethylureas
Authors: Tao E. V. P. , Staten G. S.
Published: April 2009

The synthesis of some N‐(4,5,5‐trisubstituted‐Δ2‐1,3,4‐thiadiazolin‐2‐yl)‐N,N′‐dimethylureas is described.
New reactions of deoxyvasicinone. Part 2
Authors: Dunn A. D. , Kinnear K. I.
Published: April 2009

Deoxyvasicinone (1) was shown to react with chloral, ethyl chloroacetate and chlorinated acetyl chlorides. The reactions between 1 and both acetic anhydride and vinyl acetate are reported and the structures of the products from these two reactions elucidated by pmr spectroscopy.
The use of sodium hydride in a ring closure
Authors: Georgiadis Minas P.
Published: April 2009

The use of sodium hydride for the synthesis of 1,5‐methano‐3‐benzazocine derivatives, which involves the intramolecular acylation of the α‐methylene group of tetralone by methylene isocyanate substituents, is discussed in detail.
Molecular rearrangements of five‐membered ring heteromonocycles
Authors: L'abbé Gerrit
Published: April 2009

Molecular rearrangements of five‐membered ring heterocycles are conveniently classified in five categories based on the number of participating side‐chain atoms. These include the rearrangements which operate by a ring contraction‐ring expansion mechanism, the Dimroth rearrangement, the Cornforth rearrangement, the Boulton‐Katritzky scheme, the bond‐switch rearrangements with sulfur as the pivot atom, and many other isolated cases. A concise description of these rearrangements in the monocyclic series is given with particular emphasis on the thermal reactions. The photoisomerizations have been included only when necessary for discussion, since an excellent recent review exists on this topic (ref [9]).
Crystal structure of 10‐(2′‐pyrazyl)phenothiazine and spectroscopic identification of its radical‐cations and dications
Authors: Jovanovic Misa V. , Biehl Edward R. , Rosenstein Robert D. , Chu Shirley S. C.
Published: April 2009

The crystal structure of 10‐(2′‐pyrazyl)phenothiazine has been determined by the single crystal x‐ray diffraction technique. The crystal belongs to the orthorhombic system with a space group of Pbca. The unit cell parameters are a = 10.633(3), b = 7.525(2), and c = 32.984(6)Å, with eight molecules in a unit cell. The final disagreement index, R, is 0.057 for 1944 observed reflections. The central ring of the phenothiazine ring system is in a broad conformation and the 10‐(2′‐pyrazyl)substituent is attached to the phenothiazine central ring in a boat‐axial conformation. This is the first reported phenothiazine whose 10‐substituent is perpendicular to the plane bisecting the dihedral angle of the phenothiazine nucleus.

Ultraviolet absorption maxima of the title compound in various oxidizing and non‐oxidizing medium is reported. These data indicate that the geometry of 3 changes when it is oxidized to its radical‐cations and dications.
Furopyridines. II. Bromination and nitration of furo[2,3‐b]‐, furo[3,2‐b]‐, furo[2,3‐c]‐ and furo[3,2‐c]pyridine
Authors: Shiotani Shunsaku , Morita Hiroyuki , Inoue Masatoshi , Ishida Toshimasa , Iitaka Yoichi , Itai Akiko
Published: April 2009

In order to reveal the reactivities of furopyridines, we undertook bromination and nitration of four furopyridines (1, 2, 3 and 4) whose chemical properties had been almost unknown. Bromination of 1, 2, 3 and 4 gave the corresponding trans‐2,3‐dibromo‐2,3‐dihydro derivatives 6, 8, 10 and 12, respectively, which were converted to 3‐bromofuropyridines 7, 9, 11 and 13 by treatment with sodium hydroxide in aqueous methanol. Nitration of 1 with a mixture of fuming nitric acid and sulfuric acid afforded a mixture of addition products 14a, 14b and 14c and 2‐nitro derivative 15. Both 14a and 14b were easily converted to 15 by treatment with sodium bicarbonate. Compound 2 was nitrated to give a mixture of cis‐ and trans‐2‐nitro‐3‐hydroxy‐2,3‐dihydro derivative 16a and 16b and 2‐nitro derivative 17. The cis isomer 16a was transformed to the trans isomer 16b by refluxing on silica gel in ethyl acetate. Compound 16b was dehydrated with acetic anhydride to give 17. Nitration of 3 gave a nitrolic acid derivative 20. Nitration of 4 gave a mixture of 2‐nitro derivative 22 and 3‐(trinitromethyl)pyridin‐4‐ol (23). The structures of 20 and 23 were established by single crystal X‐ray analysis. The differences of behavior observed in these reactions are discussed in connection with the results of the determination of pKa values and the relative reactivities of deuteriodeprotonation of these furopyridines.
Reaction of 1‐(2′,3′‐epoxy‐β‐D‐lyxofuranosyl)uracil with hydrogen fluoride. The unexpected formation of 1‐(3′‐fluoro‐3′‐deoxy‐β‐D‐ribofuranosyl)uracil
Authors: Misra Hemant K. , Gati Wendy P. , Knaus Edward E. , Wiebe Leonard I.
Published: April 2009

Reaction of 1‐(2′,3′‐epoxy‐β‐D‐lyxofuranosyl)uracil (1) with hydrogen fluoride afforded 3′‐fluoro‐3′‐deoxyarabinouridine (2, 13%) and 3′‐fluoro‐3′‐deoxyuridine (3, 11%). The structure of3was assigned from spectrometric data and confirmed by an unambiguous synthesis from 2′,5′‐di‐O‐trityl‐2,3′‐anhydrouridine (5) and hydrogen fluoride.
A simple synthesis of heterocyclic ring systems containing the 1,3‐oxazine nucleus
Authors: Altomare C. , Carotti A. , Casini G. , Ferappi M.
Published: April 2009

An easy, one‐step conversion of aldol adducts 1 into spiro‐derivatives of partially hydrogenated [1,3]oxazino[2,3‐a]isoquinoline 5, [1,3]oxazino[2,3‐a]phthalazine 6 and [1,3]oxazino[3,2‐a]quinoline 7 is reported.
Chemistry of thienopyridines. XXXI. A new synthesis of thieno[3,2‐b]pyridine and studies on direct substitution into its thiophene ring
Authors: Klemm L. H. , Louris John N.
Published: April 2009

Thieno[3,2‐b]pyridine (1) is synthesized in 65% overall yield for two steps which consist of addition of toluene‐α‐thiol to 2‐ethynylpyridine plus vacuum pyrolysis of the addend (7). Cis and trans forms of 7 are described. Compound 1 undergoes (a) electrophilic substitution at C‐3 to give chloro, bromo, and iodo derivatives (44–57% yields) and (b) lithiation at C‐2 (to give 1a). Intermediate 1a is converted into derivatives of 1 with halo (19–48%), formyl (54%), acetyl, and hydroxymethyl (40%) substituents at C‐2. Also described are 2‐cyano and 2,3‐dibromo derivatives of 1. Structural assignments are based on chemical transformations plus 1H and 13C nmr spectral data. The substitution pattern of 1 is compared with predictions made on the bases of analogous ring systems and molecular orbital calculations.
Structural determinations of some chloroazepine‐2,5‐diones using a lanthanide shift reagent
Authors: Wilbur D. Scott
Published: April 2009

The use of a lanthanide shift reagent, Eu(fod)3, to aid in the structural assignments of some chloroazepine‐2,5‐diones is described. The chloroazepine‐2,5‐diones, synthesized via the Schmidt reactions of chloro‐1,4‐benzoquinones, could not readily have their structures assigned by other spectroscopic methods. Correlations of plotted lanthanide induced shifts in pmr studies demonstrated that there was a large positional dependence on the magnitude of induced shifts. The large difference in the magnitude of induced shifts made it possible to assign protons and methyl substituents to specific positions on the azepine ring, thus assigning the structure of the compound.
Synthesis of 5H‐10,11‐dihydropyrazolo[5,1‐c]‐[1,4]benzodiazepinederivatives. II
Authors: Melani Fabrizio , Cecchi Lucia , Filacchioni Guido
Published: April 2009

Ethyl 3(5)‐formylpyrazole‐5(3)‐carboxylate, 2‐nitrobenzyl bromide or 2‐nitrobenzoyl chloride are the starting basic materials to prepare with a few reaction steps, pyrazolo[5,1‐c][1,4]benzodiazepines bearing at position 2 a substituted propionic chain (7–9) or bearing at position 5 a carbonyl group (12). Compounds 7–9, 12 are to be considered aza analogs of the antitumor antibiotic antramycin.
Secondary metabolites of the coelenterate echinopora lamellosa
Authors: Sanduja R. , Martin G. E. , Weinheimer A. J. , Alam M. , Hossain M. B. , van der Helm Dick
Published: April 2009

The marine coelenterate Echinopora lamellosa (class Anthozoa, family Scleractinidae) was found to contain a number of unprecedented secondary metabolites which were isolated and identified as smilagenin (I), neodunol methyl ether (II), glycyrrhetic acid (III), 3β‐acetoxyglycyrrhetic acid (IV), and 3β‐acetoxy‐11‐deoxoglycyrrhetic acid (V). The structure of neodunol methyl ether was confirmed and its absolute configuration determined by the x‐ray diffraction method.
Mass spectral fragmentation patterns of 2,5‐bis(p‐R2‐phenyl)‐(3,4)‐R1‐furans
Authors: Cortés E. , Martínez R. , Mutio A. M.
Published: April 2009

The electron impact mass spectrometric fragmentation pathways for several 2,5‐bis(p‐R2‐phenyl)‐(3,4)‐R1‐furans, I, were investigated. Our investigation of the mass spectra of these compounds revealed interesting relationships between substitution pattern in the framework of I and the fragmentation patterns.
Synthesis in the thienobenzoxazepine series. First synthesis of a diethienoxazepine
Authors: Marchand Gilles , Decroix Bernard , Morel Jean
Published: April 2009

In an investigation of novel tricyclic systems, synthesis of several thieno[2,3‐b][1,4]benzoxazepines and thieno[3,2‐b][1,5]benzoxazepines were effected by ring closure of appropriately amino aldehyde compounds. A new oxazepine fused with two heterocyclic rings, the dithieno[3,2‐b:2,3‐f][1,4]oxazepine, is described.
Application of LIS reagents in determining the stereochemistry of the 7‐phenyl‐2‐oxabicyclo[4.1.0]heptanes
Authors: Woodyard James D. , Richardson Benny R. , Hobbs Gregory D.
Published: April 2009

Stereochemical assignments are made for the endo‐ and exo‐7‐phenyl‐2‐oxabicyclo[4.1.0]heptanes by analysis of their europium doped nmr spectra.
Activation of nitriles by hydrogen bonding in cycloadditions with nitrile oxides
Authors: Corsaro Antonino , Chiacchio Ugo , Caramella Pierluigi , Purrello Giovanni
Published: April 2009

The dipolarophilic activity of aromatic nitriles in cycloaddition with benzonitrile oxides is remarkably enhanced by ortho‐acylamino substituents. The activation depends upon the solvent and can be ascribed to a hydrogen bond which assists cycloaddition.
Reactions of 1,3‐thiazine‐2,6‐dithiones. Part 6 [1]. Synthesis of 2‐alkylthio‐2,3‐dihydro‐1,3‐thiazine‐6‐thiones by reductive alkylation of 1,3‐thiazine‐2,6‐dithiones
Authors: Muraoka Motomu , Yamada Atsushi , Yamamoto Tatsuo
Published: April 2009

2‐Alkylthio‐2,3‐dihydro‐1,3‐thiazine‐6‐thiones 4 are synthesized by the reductive alkylation of 1,3‐thiazine‐2,6‐dithiones with thiolate anions.
N‐bromosuccinimide in heterocyclic synthesis. Synthesis of pyrazolo[3,4‐d]pyrimidines, Pyrimido[5,4‐e]‐as‐triazines, and pyrimido[4,5‐c]pyridazines from 6‐arylidenehydrazino‐1,3‐dimethyluracil derivatives
Authors: Kanazawa Hashime , Nishigaki Sadao , Senga Keitaro
Published: April 2009

Reactions of 6‐arylidenehydrazino‐1,3‐dimethyluracil derivatives with N‐bromosuccinimide leading to pyrazolo[3,4‐d]pyrimidines, pyrimido[5,4‐e]‐as‐triazines, and pyrimido[4,5‐c]pyridazines are described.
Mécanisme de la réaction de cyclisation en milieu aqueux de carbanilates de propargyle en méthylène‐4 oxazolidinones‐2
Authors: MespliÉ Yolande , Bergon Michel , Calmon Jean‐Pierre
Published: April 2009

Les cinétiques d'hydrolyse en milieu alcalin à 25° de chloro‐3 carbanilates de propargyle ont été suivies par spectrophotométrie ultraviolette. La catalyse complexe des ions hydroxyle, mis en évidence pour la réaction de cyclisation de ces composés en méthylène‐4 oxazolidinones‐2 a été interprétée comme résultant de l'attaque nucléophile de l'anion du substrat et de celle de l'ion hydroxyle sur la triple liaison. La première conduit directement à l'hétérocycle alors que la seconde engendre un cétocarbamate qui se cyclise ultérieurement en oxazolidinone.
Chemistry of the phenoxathiins and isosterically related heterocycles. XXXI. Synthesis of the 1,3‐diazaphenoxathiin ring system and the relationship of the 13C‐NMR chemical shift of the C‐10a resonances to the molecular dihedral angle determined by X‐Ray diffraction: A further investigation
Authors: Puig‐Torres Salvador , Martin Gary E. , Larson Steven B. , Simonsen Stanley H.
Published: April 2009

Synthesis of the 1,3‐diazaphenoxathiin ring system and the confirmation of its structure by 13C‐nmr spectroscopy and X‐ray crystallography are reported. Implications of the 13C‐nmr chemical shift of the C‐10a resonance and its relationship to the molecular dihedral angle are presented. The molecule crystallizes in the Pbca space group and was found to have a dihedral angle of 165.5(9)°, the structure refining to a final R‐factor of T = 0.0427.
Synthesis of optically active 5,6,7,8‐tetrahydroquinolines
Authors: Soccolini F. , Chelucci G. , Botteghi C.
Published: April 2009

(+)‐(R)‐5‐Methyl‐ and (+)‐(R)‐2,5‐dimethyl‐8‐isopropylidene‐5,6‐dihydro‐7H‐quinoline, 7 and 11, were synthesized by reaction of (R)‐pulegon morpholino‐enamine with acrolein or methyl vinyl ketone. The Michael adducts thus formed were reacted with hydroxylammonium hydrochloride in polar media. Compound 7 was also obtained by thermal rearrangement of the O‐allyl ether of pulegone oxime. The selectivity of both synthetic methods were rather poor (30–49%). Isolation of 7 and 11 in the pure state was accomplished by preparative glc.
The regioselectivity in the formation of pyrazolines and pyrazoles from nitrile imines
Authors: Hassaneen Hamdi M. , Hilal Rifaat H. , Elwan Nehal M. , Harhash Abdelhamid , Shawali Ahmad S.
Published: April 2009

The 1,3‐cycloaddition of the nitrile imines 2a‐e to the carbon‐carbon double bond in benzalacetophenone leads to the formation of 4‐phenyl‐5‐benzoylpyrazolines 3a‐e which were converted into 4‐phenyl‐5‐benzoylpyrazoles 5a‐e upon treatment with chloranil in xylene. However, the cycloaddition of 2a‐e to the carbon‐carbon double bond in the enol tautomer of dibenzoylmethane gives the regioisomers 5‐phenyl‐5‐hydroxy‐4‐benzoylpyrazolines which loose elements of water to yield 4‐benzoyl‐5‐phenylpyrazoles 6a‐e. The orientations in these reactions are interpretted in terms of the Frontier Molecular Orbital theory. The structures of the products 3, 5 and 6 were substantiated by their chemical reactions and alternate synthesis wherever possible.
Facile addition of methyl lithium to a 4‐vinylpyridine system
Authors: Miller David
Published: April 2009

The rapid addition of methyl lithium to the 4‐vinylpyridine system present in 4‐{2,6‐dihydroxy‐4‐(3‐methyl‐2‐octyl)phenyl}‐2‐methyl‐4‐(4‐pyridyl)but‐3‐en‐2‐ol (2) is reported. The α and β‐4‐{2,6‐dihydroxy‐4‐(3‐methyl‐2‐octyl)phenyl}‐2,3‐dimethyl‐4‐(4‐pyridyl)butan‐2‐ols 4 and 5 formed, are cyclised by heating with 5N hydrochloric acid to trans and cis‐3,4‐dihydro‐5‐hydroxy‐7‐(3‐methyl‐2‐octyl)‐4‐(4‐pyridyl)‐2,2,3‐trimethyl‐2H‐1‐benzopyran 6 and 7 respectively.
Convenient synthesis of fused heterocycles from α‐ketohydroximoyl chlorides and heterocyclic amines
Authors: PÁrkÁnyi Cyril , Abdelhamid Abdou O. , Cheng John C. S. , Shawali Ahmad S.
Published: April 2009

Nitroso derivatives of imidazo[1,2‐a]pyridine (11, 13, 14), imidazo[1,2‐a]pyrimidine (15), imidazo[1,2‐a]pyrazine (16), imidazo[1,2‐b]pyrazole (17), and imidazo[1,2‐b]‐1,2,4‐triazole (19) were obtained in good yields from α‐ketohydroximoyl chlorides3and 2‐aminopyridines (4–6), 2‐aminopyrimidine (7), 2‐aminopyrazine (8), 5‐amino‐3‐phenylpyrazole (9), and 3‐amino‐2H‐1,2,4‐triazole (10), respectively. Under different conditions, the reaction of3with 3‐amino‐2H‐1,2,4‐triazole (10) and 2‐aminopyrazine (8) afforded the noncyclized substitution products18and22, respectively. The structures of the products were assigned and confirmed on the basis of their elemental analyses, spectral data, and alternate synthesis wherever possible.
Analogues du nor‐B benzomorphane. I. Synthese des méthano‐3,5 tétrahydro‐2,3,4,5 1H‐benzazépines et dérivés
Authors: Escale Roger , El Khayat Ammar , Vidal Jean‐Pierre , Girard Jean‐Pierre , Rossi Jean‐Claude
Published: April 2009

De nouveaux édifices homologues du nor‐B benzomorphane, les méthano‐3,5 tétrahydro‐2,3,4,5 1H‐benzazépines‐1 et 2 sont synthétisés en vue de leur étude au niveau du système nerveux central. Les dérivés nitrés et aminés correspondant aux positions 7 et 8 sont obtenus par nitration et réduction sélective.
The crystal structure of 1‐(Piperidin‐1‐yl)‐4‐t‐butyl‐7‐thiabicyclo[4.2.0]‐octane 7,7‐Dioxide [1α,4α,6α]
Authors: BrÚckner S. , Ganazzoli F. , Fatutta S. , Pitacco G. , Valentin E.
Published: April 2009

The crystal structure of the title compound is described.
Synthesis of novel imidazo[1,2‐a][3,1]benzothiazines 4, imidazo[1,2‐a]‐[1,2,4]benzotriazines 5, and 4H‐imidazo[2,3‐c]pyrido[2,3‐e][1,4]oxazines 6
Authors: Gauthier Jean , Duceppe Jean Simon
Published: April 2009

Starting from the readily available 2‐aminobenzhydrols (7), 3‐amino‐1,2,4‐benzotriazine (11) and 2‐amino‐3‐pyridinol (12), novel derivatives of 5‐phenyl‐5H‐imidazo[1,2‐a][3,1]benzothiazine‐2‐carboxylic acid, ethyl ester (4), imidazo[2,1‐c][1,2,4]benzotriazine‐2‐carboxylic acid, ethyl ester (5) and 4H‐imidazo[2,3‐c]pyrido‐[2,3‐e][1,4]oxazine (6) were prepared.
The mass spectra of some bis[5‐(2‐mercapto‐1,3,4‐thiadiazolyl)]methyl and aryl derivatives
Authors: Pappalardo Sebastiano , Bottino Francesco , Di Grazia Michele
Published: April 2009

The general fragmentation patterns of five selected title compounds are described. The most significant mass spectral features arise from the interaction of aryl substituents with the adjacent heterocyclic ring. The decomposition of the compounds bearing an ortho nitro group in the S‐aryl moieties is strongly affected by a prominent “ortho effect”.
N‐acylation of 1,3‐dimethyl‐6‐aminouracils. A reversal in the regiospecificity of an electrophilic substitution induced by an intramolecular proton‐transfer
Authors: Bernier Jean‐Luc , HÉnichart Jean‐Pierre , Warin Vincent
Published: April 2009

Electrophilic reactions of 1,3‐dimethyl‐6‐aminouracil lead to 5‐substituted derivatives. The introduction of a dialkylaminoalkylamino chain in the 6‐position of 1,3‐dimethyluracil modifies the regiospecificity of the acylation reaction to give N‐6 acylated compounds. This reversal in acylation is induced by an intramolecular proton‐transfer which introduces a change in the electron density of the enamine system. The cyclic transition state and the spatial conformation of the final products substantiate the proposed mechanism, on the basis of X‐ray and 1H nmr data.
N‐quaternary compounds. Part LIX. Facile synthesis of 3‐vinyl‐4(3H)‐pyrimidinethiones
Authors: Pedersen Ansgar Heim , Undheim Kjell
Published: April 2009

3‐Vinyl derivatives of 4(3H)‐pyrimidinethiones have been prepared from 2,3‐dihydrothiazolo[3,2‐c]pyrimidinium derivatives through ring‐opening by a strong base such as potassium t‐butoxide in DMF. The pyrimidinium derivative is initially prepared from 4(3H)‐pyrimidinethiones. 3‐Vinyl‐4(3H)‐pyrimidinethiones are also formed by the ready decarboxylation of 2,3‐dihydrothiazolo[3,2‐c]pyrimidinium‐3‐carboxylates. In the mass spectrometer the nature of the volatile species was elucidated by means of appearance potentials and fragmentation patterns.
The synthesis of 1‐substituted 6‐amino‐1H‐pyrrolo‐[3,2‐c]pyridin‐4(5H)‐ones
Authors: Schneller Stewart W. , Luo Jiann‐Kuan , Hosmane Ramachandra S. , DÚrrfeld Rainer H.
Published: April 2009

The synthesis of 1‐methyl‐ (1a) and 1‐benzyl‐6‐amino‐1H‐pyrrolo[3,2‐c]pyridin‐4(5H)‐one (1b) from the appropriate N‐alkylaminoacetaldehyde is described. These provide examples of a synthetic procedure that can be used to prepare 1‐substituted 6‐amino‐1H‐pyrrolo[3,2‐c]pyridin‐4(5H)‐ones wherein the N‐1 substituent is regiospecifically placed.
Synthesis of 5‐amino‐1,3‐dimethylpyrazol‐4‐yl aryl ketones
Authors: Dewald H. A.
Published: April 2009

A convenient preparation of 5‐amino‐1,3‐dialkylpyrazol‐4‐yl heterocyclic ketones is reported. They are prepared from the reaction of heterocyclic esters with the di‐lithio derivative from N‐(4‐bromo‐1,3‐dimethyl‐1H‐pyrazol‐5‐yl)benzamide (1).
Reaction of glyceraldehyde with aryl and alkyl chloroformates
Authors: Podraza Kenneth F.
Published: April 2009

A number of 2,5‐bis(aryl‐ and alkyloxycarbonyloxymethylene)‐3,6‐bis(aryl‐ and alkoxycarbonyloxy)‐1,4‐dioxanes 5a‐d have been prepared by the reaction of glyceraldehyde with aryl and alkyl chloroformates. Bis aryl carbonates were also formed under certain conditions in this reaction. Nuclear magnetic resonance analysis of 5c indicated that it existed in a chair conformation with all the substituents in an equatorial position.
A novel synthesis for quinoline derivatives
Authors: Fahmy A. M. , Badr M. Z. A. , Mohamed Y. S. , Abdel‐Latif F. F.
Published: April 2009

Condensation of ethyl 2‐(2‐oxo‐2,3‐dihydro‐1H‐indolid‐3‐ene)cyanoacetate and/or 2‐(2‐oxo‐2,3‐dihydro‐1H‐indolid‐2‐ene)malononitrile with 3‐methylpyrazolin‐5‐one, 1‐phenyl‐3‐methyl‐pyrazolin‐5‐one, benzoyl acetonitrile or ethyl acetoacetate affords different substituted quinolines. The reaction is suggested to proceed through a nucleophilic addition followed by ring opening and recyclization steps.
Nucleophilic substitution of halopyridines by benzenethiolate anion via a radical chain mechanism
Authors: Kondo Shuji , Nakanishi Minoru , Tsuda Kazuichi
Published: April 2009

2‐Halopyridines 1a‐d reacted with sodium thiophenoxide in DMF at 80° to afford the ipso‐substitution products. The following relative order of reactivity was observed: 2‐iodopyridine (1a) ∼ 2‐bromopyridine (1b) ≫ 2‐chloropyridine (1c) ∼ 2‐fluoropyridine (1d). The reaction of 1b is inhibited by the electron scavenger azobenzene and by the radical scavenger benzoqoquinone. Furthermore, results of the reaction of 3‐bromopyridine (2b) serve to rule out pyridyne mechanism. It is reasonable to suggest therefore that the reaction proceeds through the radical chain process containing one electron transfer, that is SRN1.
Activated nitriles in heterocyclic synthesis. The reaction of cinnamonitrile derivatives with active methylene reagents
Authors: Abed Nosrat Mustafa , Hafez Ebtisam Abdel Aziz , Elsakka Ibraheim , Elnagdi Mohamed Hilmy
Published: April 2009

The reaction of substituted cinnamonitrile derivatives with cyanoacetanilide and with ethyl acetoacetate produced several new polyfunctional pyridine and pyran derivatives. Evidence for assigned structure of the reaction products and the possible mechanisms of their formation is presented.
Eight‐membered organosulfur heterocycles. Synthesis of dibenzo[d,g][1,3,6,2]dioxathiaphosphocin and dibenzo[d,g][1,3,6,2]dioxathiasilocin ring systems
Authors: Pastor Stephen D. , Spivack John D. , Steinhuebel Leander P.
Published: April 2009

The reaction of 2,2′‐thiobisphenols with either phenylphosphonous dichloride or phosphorus trichloride followed by an alcohol gave derivatives of the dibenzo[d,g][1,3,6,2]dioxathiaphosphocin ring system. The analogous reaction of 2,2′‐thiobisphenols with alkyl and aryl dichlorosilanes gave the heretofore unreported dibenzo[d,g][1,3,6,2]dioxathiasilocin ring system. The analytical and spectral data are reported.
The insertion and extrusion of heterosulfur bridges. XII. Selectivity and side reactions in the bridging process
Authors: Klemm L. H. , Pou Sovitj , Detlefsen W. D. , Higgins Clay , Lawrence Ross F.
Published: April 2009

1‐Phenylnaphthalene undergoes sulfur bridging at 500° in the presence of hydrogen sulfide and a heterogeneous catalyst to produce benzo[b]naphtho[1,2‐d]thiophene (13%). 3‐Methylphenanthrene and 9‐formylphenanthrene diethyl acetal (7b) give sulfur bridging to produce phenanthro[4,5‐bcd]thiophene, i.e. with loss of the ring substituent. Additionally, 7b hydrogenolyzes to 9‐methylphenanthrene. With decadeuteriobiphenyl as a substrate, the dibenzothiophene formed, as well as the biphenyl recovered, is largely devoid of deuterium label. Confirmation that benzene and toluene react under sulfur‐bridging conditions is presented.
The synthesis of 3‐aryl‐6‐alkylpyridazines
Authors: Liang Jason
Published: April 2009

Nine compounds of general structure R‐X‐Y‐R' where X is a para‐disubstituted phenyl ring and Y is a 3,6‐disubstituted‐pyridazine ring were synthesized. These can be used as liquid crystal dopents. A general procedure for their synthesis was developed. N‐Alkyl benzene and ethyl butyrylacetate were used as starting materials. The purification of reaction intermediates was not necessary if preparative hplc was used to purify the final products. Very pure materials were obtained with good yield. Their structure was confirmed by carbon 13 nmr.
Study of the azide ion reactivity towards heterocyclic cations. V. Syntheses, thermal and photochemical rearrangements of α,α'‐diphenylpyridylazidomethanes
Authors: Desbène P. L. , Jehanno N.
Published: April 2009

The syntheses of α,α'‐diphenylpyridylazidomethanes are reported and the thermal and photochemical rearrangements of these azides are studied. For the thermolysis and photolysis of these azides a step by step mechanism is proposed. The differences between thermolysis and photolysis should come from the nature of the nitrenoide state involved; the 1Δ electrophilic state in thermolysis and the less selective 1σ diradical state in photolysis.
Study of the azide ion reactivity towards heterocyclic cations. VII. Application of thermal and photochemical rearrangements of α,α'‐diphenylpyridylazidomethanes to the syntheses of 4‐pyridyldibenzoheteroazepines
Authors: Desbène P. L. , Jehanno N.
Published: April 2009

The application of thermal and photochemical rearrangements of α,α'‐diphenylpyridylazidomethanes to the synthesis of 4‐pyridyldibenzoheteroazepines is reported. This route provides easily the 11‐(4‐pyridyl)dibenzo[b,f][1,4]oxazepine and the 11‐(4‐pyridyl)dibenzo[b,f][1,4]thiazepine with good yields. In the case of the 11‐(4‐pyridyl)dibenzo[b,f][1,4]selenazepine this route is less interesting because of the instability of this compound. The previously proposed mechanisms for the thermal and photochemical rearrangements of α,α'‐diphenylazidomethanes can be applied to the azides examined.
Synthesis of the 5H‐pyrrolo[2,1‐a]isoindole ring with 1,3‐dipolar cycloaddition reactions
Authors: New J. S. , Yevich J. P.
Published: April 2009

The 1,3‐dipolar cycloaddition reaction between mesoionic oxazolines, formed from either 1,3‐dihydro‐2‐substituted‐2H‐isoindole‐1‐carboxylic acids or 1,3‐dihydro‐1‐oxo‐α‐substituted‐2H‐isoindole‐2‐acetic acids, and dimethylacetylene dicarboxylate has led to the synthesis of several 5H‐pyrrolo[2,1‐a]isoindole derivatives 9a‐d.
Thiazolopyridine analogs of nalidixic acid. 2. Thiazolo[4,5‐b]pyridines
Authors: Leysen D. C. , Haemers A. , Bollaert W.
Published: April 2009

A series of 2‐substituted 4‐ethyl‐4,7‐dihydro‐7‐oxothiazolo[4,5‐b]pyridine‐6‐carboxylic acids were synthesized. Antibacterial activity was tested in vitro. None of the new compounds prepared showed any interesting antibacterial activity in vitro against the strains tested.
Reactions of alkali metal derivatives of some heterocyclic amines
Authors: Hough T. L. , Jones G. P.
Published: April 2009

Procedures are described for converting 2‐amino‐1,3,4‐oxa‐ and thiadiazoles into various products in one‐pot syntheses. The preparative method employs alkali metal derivatives of the heterocyclic amines as the reactive species.
Etude dans la série des pyrrolidinones: Réaction de mannich du glutamate de diéthyle
Authors: Rigo B. , Fossaert E. , De Quilacq J. , Kolocouris N.
Published: April 2009

Les esters N‐arylméthyl pyroglutamiques et leurs dérivés possèdent des propriétés pharmaceutiques intéressantes; leur formation par réaction de Mannich a été étudiée. Le réactif de départ de ces réactions doit ětre le glutamate de diéthyle car des dérivés cyclisés comme le pyroglutamate de méthyle ou le N‐méthylol pyroglutamate de méthyle ne semblent pas réagir.
1,3‐Dipolar cycloaddition reactions of 2‐phenyl‐4‐arylidene‐5(4H)‐oxazolones with nitrile oxides
Authors: Argyropoulos N. G. , Coutouli‐Argyropoulou E.
Published: April 2009

Stable nitrile oxides are added stereospecifically and regioselectively to the carboncarbon double bond of 2‐phenyl‐4‐arylidene‐5(4H)‐oxazolones resulting spiro‐derivatives 3, 5. The spectral properties of the reaction products are discussed. The cycloadducts give several substituted isoxazolines via an opening of the oxazolone ring with nucleophilic reagents.
The synthesis of 1H‐benzimidazole derivatives containing a 9H‐xanthene or 9H‐thioxanthene ring
Authors: Okabayashi Ichizo , Fujiwara Hidetoshi
Published: April 2009

2‐(9H‐Xanthen‐9‐ylmethyl)‐1H‐benzimidazole (2a) was prepared by condensing 9H‐xanthene‐9‐acetic acid (1a) with 1,2‐benzenediamine. Similarly, 2‐(9H‐thioxanthen‐9‐ylmethyl)‐1H‐benzimidazole (2b) and its S,S‐dioxide (2d) were obtained. Compound 2d was also prepared by oxidizing 2b with hydrogen peroxide in acetic acid. Heating of 9H‐thioxanthene‐9‐acetic acid 10‐oxide (1c) with 1,2‐benzenediamine gave 9‐methylene‐9H‐thioxanthene (3). 2‐(9H‐Thioxanthen‐9‐ylmethyl)‐1H‐benzimidazole S‐oxide (2c) was obtained by oxidizing 2b with m‐chloroperbenzoic acid in acetone.
Reaction of 2‐dimethylaminomethylene‐1,3‐diones with Dinucleophiles. IV. Synthesis of 5,7‐dihydrothiopyrano[3,4‐c]pyrazol‐4(1H)‐ones, 5H‐Thiopyrano[4,3‐d]isoxazol‐4(7H)‐one and 6H‐Thiopyrano[3,4‐d]pyrimidin‐5(8H)‐ones
Authors: Menozzi Giulia , Mosti Luisa , Schenone Pietro
Published: April 2009

The reaction of 2H‐thiopyran‐3,5(4H,6H)‐dione with N,N‐dimethylformamide dimethyl acetal gave in good yield 4‐dimethylaminomethylene‐2H‐thiopyran‐3,5(4H,6H)dione (II), which afforded 1‐substituted 5,7‐dihydrothiopyrano[3,4‐c]pyrazol‐4(1H)‐ones with aliphatic and aromatic hydrazines, 5H‐thiopyrano[4,3‐d]isoxazol‐4(7H)‐one (IV) with hydroxylamine hydrochloride and 2‐substituted 6H‐thiopyrano[3,4‐d]pyrimidin‐5(8H)‐ones with amidines and guanidines, generally in satisfactory yields. 4‐(t‐Butylhydrazonoformyl)‐2H‐thiopyran‐3,5(4H,6H)‐dione was isolated as an intermediate in the reaction of II with t‐butylhydrazine, whereas formamidine gave with II 4‐iminoformyl‐2H‐thiopyran‐3,5(4H,6H)‐dione as the sole product. The isoxazole IV isomerized easily with sodium methoxide to 3,4,5,6‐tetrahydro‐5,5‐dihydroxy‐3‐oxo‐2H‐thiopyrano‐4‐carbonitrile.
Reaction of sulfene and dichloroketene with N,N‐disubstituted α‐aminomethyleneketones. Synthesis of 5H‐pyrano[3,4‐e]‐1,2‐oxathiin and 2H,5H‐Pyrano[4,3‐b]pyran derivatives
Authors: Menozzi Giulia , Mosti Luisa , Schenone Pietro
Published: April 2009

The polar 1,4‐cycloaddition of sulfene to N,N‐disubstituted (E)‐3‐aminomethylene‐2,3,5,6‐tetrahydro‐4H‐pyran‐4‐ones II, prepared from 2,3,5,6‐tetrahydro‐4H‐pyran‐4‐one via the 3‐hydroxymethylene derivative, occurred only in the case of aliphatic N‐substitution to give, generally in satisfactory yield, 4‐dialkylamino‐3,4,7,8‐tetrahydro‐5H‐pyrano[3,4‐e]‐1,2‐oxathiin 2,2‐dioxides, which are derivatives of the new heterocyclic system 5H‐pyrano[3,4‐e]‐1,2‐oxathiin. The cycloaddition of dichloroketene to II occurred only in two cases of aromatic N‐substitution to give 3,3‐dichloro‐3,4,7,8‐tetrahydro‐4‐(methylphenyl)(diphenyl)amino‐2H,5H‐pyrano[4,3‐b]pyran‐2‐ones IVi,l. Dehydrochlorination of IV with triethylamine was successful only in the case of IVl to give 3‐chloro‐7,8‐dihydro‐4‐diphenylamino‐2H,5H‐pyrano[4,3‐b]pyran‐2‐one in low yield.
The reactions of arylamines with chelidonic acid
Authors: Katritzky Alan R. , Murugan Ramiah , Sakizadeh Kumars
Published: April 2009

Depending on the conditions, and the basicity of the amine, arylamines react with chelidonic acid to yield five different types of product: salts, N‐arylchelidamic acids, N‐aryl‐4‐pyridone‐2‐carboxylic acids, N‐aryl‐4‐pyridones, or chelidamic acid itself.
Zur elektrophilen Substitution des Xanthylium‐Ions an Indolen. Untersuchungen zur Positionsselektivität
Authors: Deschner R. , Pindur U.
Published: April 2009

The indoles 3, 5, 7, 9 and 11 yield xanthenylindoles in the reaction with the SN1‐active reagent xanthydrole (1) by acid catalysis. The regioselectivity of this electrophilic heteroaromatic substitution is predominantly controlled by the acid concentration, by the temperature and by the stoichiometric composition of the reactants. An order of positions which is supported by selectivity on the indole nucleus is presented in the experimental results of this model reaction.
2‐Phenylphthalimidine derivatives. A probable formation mechanism of adducts from 3‐benzylidenephthalide and aniline
Authors: Scartoni Valerio , Tognetti Tiziana
Published: April 2009

3‐Benzyl‐3‐hydroxy‐2‐phenylphthalimidine (1) and 3‐anilino‐3‐benzyl‐2‐phenylphthalimidine (2), the unusual adduct, are obtained from the title compounds. 3‐Alkoxy‐3‐benzyl‐2‐phenylphthalimidines 3 are synthesized. The behaviour of 1, 3‐benzylidene‐2‐phenylphthalimidines (4 and 5), 3‐(α‐bromobenzylidene)‐2‐phenylphthalimidines (6 and 7) with respect to bases and the preparation of the open tautomer 13 of 1 and its hydrochloride are described. A hypothetical mechanism about the formation of 1 and 2 is suggested.
Synthesis and antimalarial properties of 2,4‐diamino‐6‐[(aryl)thio, sulfinyl, and sulfonyl]pyrido[3,2‐d]pyrimidines
Authors: Colbry Norman L. , Elslager Edward F. , Werbel Leslie M.
Published: April 2009

The synthesis and antimalarial activity of a series of 2,4‐diamino‐6‐[(aryl)thio, sulfinyl and sulfonyl]pyrido‐[3,2‐d]pyrimidines is described. Nitration of 2,6‐dichloropyridine provided the 3‐nitro derivative which was converted to 6‐chloro‐3‐nitro‐2‐pyridinecarbonitrile (V) with cuprous cyanide. Condensation of an aryl thiol with V gave the 6‐arylthiopyridines VI which were reduced with iron in hydrochloric acid and condensed with chloroformamidine to give the 6‐arylthiopyrido[3,2‐d]pyrimidin‐2,4‐diamines X. Alternatively V was reduced to the amine VIII condensed with chloroformamidine and the resulting 6‐chloropyrido[3,2‐d]pyrimidine (IX) was treated with an arylthiol. Oxidation of X provided sulfinyl and sulfonyl analogs.
Synthèse de benzopyrannopyridines et de dihydrobenzoquinoléines
Authors: Bellassoued‐Fargeau Marie‐Claude , Maitte Pierre
Published: April 2009

La cycloaddition thermique d'un système α‐énone avec l'oxyde de vinyle et d'éthyle conduit à un éthoxy‐2 dihydropyranne aisément transformé en pyridine par action du chlorhydrate d'hydroxylamine. Ce schéma réactionnel a permis de réaliser la synthèse de benzopyrannopyridines et de dihydrobenzoquinoléines.
2H‐1,2,4,6‐thiatriazin‐3(4H)‐one 1‐oxides and their regioselective N4‐methylation and ‐amination
Authors: Nakayama Yoshinori , Sanemitsu Yuzuru
Published: April 2009

The syntheses of 2H‐1,2,4,6‐thiatriazin‐3(4H)‐one 1‐oxides and 1,1‐dioxides is described. The reaction of 1‐carbamoyl‐2‐methylisothioureas 2 with thionyl chloride gave 2H‐1,2,4,6‐thiatriazin‐3(4H)‐one 1‐oxides 3 in high yields. The treatment of 3 with either diazomethane or O‐(2,4‐dinitrophenyl)hydroxylamine furnished regioselectively N4‐methylated and N4‐aminated 2H‐1,2,4,6‐thiatriazin‐3(4H)‐one 1‐oxides, respectively. Subsequent dimethylamination of 4 followed by oxidation with m‐chloroperoxybenzoic acid led to 2H‐1,2,4,6‐thiatriazin‐3(4H)‐one 1,1‐dioxides 6a‐c.
Synthesis of 2‐substituted naphtho[1′,2′:4,5]thiazolo[3,2‐b]‐1,2,4‐triazoles
Authors: Liu Kang‐Chien , Shih Bi‐Jane , Tao Tung‐Mei
Published: April 2009

N‐Amination of 2‐aminonaphtho[1,2‐d]thiazole (1) with O‐mesitylenesulfonylhydroxylamine (2) afforded the corresponding 2,3‐diaminonaphthothiazolium salt 3a. Cyclocondensation of 3a or its free base 3b with appropriate carboxylic acid derivatives 4a‐f gave the title compounds 5a‐f in satisfactory yields (54–95%). Structures of the products were assigned on the bases of spectral and elemental analyses.
Syntheses of 11‐hydroxy and 11‐hydroxy‐11‐methyl‐14‐methoxy‐14‐azadispiro[5.1.5.2]pentadec‐9‐ene‐7,15‐diones
Authors: Neelima  , Bhaduri A. P.
Published: April 2009

A facile synthesis, which permits regioselective incorporation of hydroxy and/or methyl substituents at position 11 of 14‐methoxy‐14‐azadispiro[5.1.5.2]pentadec‐9‐ene‐7,15‐dione, has been described.
The synthesis of thienocycloheptenoindoles
Authors: Abarca Belén , Ballesteros Rafael , Jones Gurnos
Published: April 2009

A synthesis of the methylthieno[3,2‐c]cyclohepteno[b]indole 7 from 2‐methylthieno[3,2‐b]cycloheptanone3is described. Unsuccessful attempts to prepare the isomeric thienocycloheptenoindole system present in formula2, from the dihydrobenzothiophenone8, and from derivatives of 5‐(2‐thienyl)‐4‐oxopentanoic acid,17and18, and fromN‐benzylcycloheptindol‐1‐one22were unsuccessful. The preparation of 4,5‐dihydro‐2‐phenyl‐1‐thienylmethyl‐3H‐pyridazin‐3‐one20and of the 5‐aminopyrazole21are reported.
Heterocyclic studies. 2. 5‐Chloro‐1H‐1,2,3‐triazole‐4‐carboxaldehydes, preparation and rearrangement reactions
Authors: Olesen Preben H. , Nielsen Flemming E. , Pedersen Erik B. , Becher Jan
Published: April 2009

A general procedure for synthesis of 5‐chloro‐1H‐1,2,3‐triazole‐4‐carboxaldehydes 4 and the rearrangement reaction of 4‐(N‐substituted)iminomethylene‐1H‐1,2,3‐triazol‐5‐ols 6 into N‐substituted‐1H‐1,2,3‐triazole‐4‐carboxamides 7 are described.
Composés sulfurés hétérocycliques. CII. Action de l'hydroxylamine sur les dihydro‐1,2 benzothiazine‐3,1 thiones‐4
Authors: Legrand Louis , Lozac'h Noël
Published: April 2009

L'hydroxylamine réagit sur les alkyl‐1 dihydro‐1,2 benzothiazine‐3,1 thiones‐4 (1) en donnant des alkyl‐1 hydroxy‐3 dihydro‐2,3 1H‐quinazolinethiones‐4 (2). En milieu neutre, le même réactif transforme les aryl‐1 dihydro‐1,2 benzothiazine‐3,1 thiones‐4 (3) en aryl‐1 hydroxyimino‐4 dihydro‐1,4 2H‐benzothiazines‐3,1 (4). En milieu acide, les mêmes produits conduisent aux aryl‐1 hydroxy‐3 dihydro‐2,3 1H‐quinazolinethiones‐4 (5), généralement accompagnées de leurs isomères 4. Les thiones 2 et 5, ainsi que les oximes 4, chauffées à 200°, se décomposent en donnant, en proportions variables, des 1H‐quinazolinethiones‐4 (6) ou (7), des 1H‐quinazolinones‐4 (9) et des dihydro‐2,3 1H‐quinazolinethiones‐4 (11). Les 1H‐quinazolinethiones‐4 (7), par action de l'iodure de méthyle, donnent des iodures de méthylthio‐4 quinazolinium‐1 (12) hydrolysables en 1H‐quinazolinones‐4 (9) qui peuvent aussi être obtenues par action du N‐oxyde de benzonitrile sur les thiones correspondantes. Les aryl‐1 1H‐quinazolinethiones‐4 (7) réagissent aisément sur les nucléophiles XNH2 pour donner divers dérivés de l'imino‐4 dihydro‐1,4 quinazoline. Tandis que par action de l'iodure de méthyle les thiones 7 subissent une S‐méthylation, par action du même réactif, les aryl‐1 1H‐quinazolinones‐4 (9) donnent des iodures d'aryl‐1 méthyl‐3 oxo‐4 dihydro‐3,4 quinazolinium‐1 (18) par N‐méthylation. Les structures proposés ont été confirmées par spectrométries uv et ir, ainsi que par rmn.
Alkylation des β‐énaminoesters cycliques: Relation entre la taille et la réactivité
Authors: Célérier Jean‐Pierre , Deloisy‐Marchalant Elisabeth , Lhommet Gérard
Published: April 2009

Les β‐enaminoesters cycliques sont C‐alkylés régiospécifiquement et seul l'isomère Z est obtenu. Les conditions opératoires différent selon la taille du cycle, plus douces avec les cycles de grande taille et plus drasti‐ques avec les petits cycles où la conjugaison est plus importante. Différentes données physicochimiques permettent d'avencer une explication reliant la différence de réactivité avec la taille du cycle des β‐énaminoesters.
Synthèse de derivès du nitro‐5 imidazole potentiellement actifs en chimiothèrapie
Authors: Alcalde Ermitas , Mañás Laura , Valls Natividad , Elguero José
Published: April 2009

Six derivés du méthyl‐2 nitro‐5 imidazole portant en position 1 une chaîne CH2CH2Het, Het étant un sel de pyridinium ou d'imidazolium 1‐substitué ont été synthétises. Ils ont fait l'objet d'une étude rmn, proton et carbone‐13, comparativement á d'autres nitroimidazoles. Ces composés ne présentent pas d'activité cytostatique.
The thermal isomerization of 1‐(α‐aroyloxybenzylideneamino)‐4,5‐di‐methyl‐1,2,3‐triazoles (isoimides) to the corresponding imides
Authors: Maroulis A. J. , Hadjiantoniou‐Maroulis C. P.
Published: April 2009

The title isoimides rearrange upon heating to the corresponding imides through a [1,3] O⇀N aroyl transfer. The reaction is slightly accelarated by electron withdrawing substituents in the migrating moiety and retarded by electron donating as it is suggested by the positive (+0.5) Hammett ϱ value. The mechanism operating is either a rate determining nucleophilic attack by the nitrogen lone pair on the carbonyl carbon or a sigmatropic [π2s + σ2a] process which does not involve the lone pair of electrons on nitrogen and π or‐bitals of the carbonyl group.
Synthesis and CMR analysis of phenoxazinone derivatives related to the actinomycin D chromophore
Authors: Sehgal Raj K. , Sengupta Sisir K. , Dieter R. Karl
Published: April 2009

Synthesis of 2‐deamino‐ and 2‐deamino‐2‐nitro‐chromophores of actinomycin was accomplished by reaction of nitrous acid in fluoroboric acidviadiazotization of the 2‐amino group in the chromophore. Structural assignments were made by cmr and pmr.
Préparation d'aryloxyméthyl‐1 triazoles‐1,2,3
Authors: Loubinoux Bernard , Colin Jean‐Luc , Tabbache Samir
Published: April 2009

La synthèse d'aryloxyméthyl‐1 triazoles‐1,2,3, régulateurs de croissance potentiels des végétaux, est réalisee par cycloaddition de composés acétyléniques sur les azides correspondants; ces derniers sont eux‐mêmes préparés par réaction entre l'azidure de sodium et les chlorures d'aryloxyméthyles.
Dérivés de la dihydro‐2,4 triazole‐1,2,4 thione‐3 et de l'amino‐2 thiadiazole‐1,3,4 à partir de nouvelles thiosemicarbazones d'esters
Authors: Malbec Frédérique , Milcent René , Barbier Géo
Published: April 2009

Une nouvelle synthèse générale des dihydro‐2,4 triazole‐1,2,4 thiones‐3 disubstituées en position 4 et 5 est proposée. Ces hétérocycles sont obtenus par action d'amines primaires, d'arylhydrazines ou d'aroylhydrazines sur les thiosemicarbazones d'esters. Celles‐ci sont préparées par action de chlorhydrates d'iminoéthers sur la thiosemicarbazide dans le diméthylformamide. Les thiosemicarbazones se prêtent à d'autres réactions avec les acides forts, les anhydrides et chlorures d'acides; par thermolyse, ils donnent des dérivés de l'amino‐2 thiadiazole‐1,3,4. Enfin, deux dérivés du [1,2,4triazolo][3,4‐b]thiadiazole‐1,3,4 ont été préparés.
The reaction of chlorosulfonyl isocyanate with epoxides. A novel conversion of epoxides to cyclic carbonates
Authors: Murthy K. S. Keshava , Dhar D. N.
Published: April 2009

The facile reaction of chlorosulfonyl isocyanate (CSI) with epoxides is described. The initially formed 2‐chlorosulfonylimino‐1,3‐dioxolane 2a‐e and N‐chlorosulfonyl‐1,3‐oxazolidin‐2‐one 3a‐e derivatives undergo smooth hydrolysis to yield the corresponding 1,3‐dioxolan‐2‐one 4a‐e and 1,3‐oxazolidin‐2‐one 5a‐e derivatives respectively. This reaction sequence provides a convenient one‐pot method for the conversion of epoxides to cyclic carbonates. Substrates such as 1g‐i are exceptions to this otherwise general reaction pathway.