bluuebunny/crossref_metadata_2025_split huggingface dataset:
Angular polycyclic thiophenes containing two thiophene rings. Part II
Authors: Tedjamulia Marvin L. , Kudo Hirotaka , Castle Raymond N. , Lee Milton L. 
Published: April 2009

AbstractThe syntheses of naphtho[1,2–6:7,6‐b′]bisbenzo[b]thiophene (4), naphtho[1,2–6:7,8‐b′]bisbenzo[b]thiophene (5), naphtho[2,1‐b:7,6‐b′]bisbenzo[b]thiophene (8), naphtho[2,1‐b:7,8‐b′]bisbenzo[b]thiophene (9), naphtho‐[1,2–6:5,6‐b′]bisbenzo[b]thiophene (14), naphtho[1,2–6:6,5‐b]bisbenzo[b]thiophene (17) and naphtho[2,1–6:‐6,5‐b′]bisbenzo[b]thiophene (23) are reported.
Reactivities of 3‐(1‐Azolyl)‐2‐alken‐1‐ones and the related compounds with pyrrolidine
Authors: Kashima Choji , Tajima Tadakuni , Higuchi Chihiro , Omote Yoshimori 
Published: April 2009

AbstractFrom the rate constants of the reaction with pyrrolidine, the reactivities of 3‐(1‐azolyl)‐2‐alken‐1‐ones with nucleophiles were evaluated to be rather high. Especially the reactivities of the quaternary salts of 3‐(1‐imidazolyl)‐2‐alken‐1‐ones were nearly equal to those of 3‐chloro‐2‐alken‐1‐ones. In conclusion, 3‐(1‐imidazolyl)‐2‐alken‐1‐ones satisfied the practical requirements for the starting materials of the synthesis of 3‐hetero‐substituted 2‐alken‐1‐ones.
Synthesis of 3H[1,2]diazepino[5,6‐b]indole and 3H[1,2]diazepino[4,5‐b]indole derivatives
Authors: Monge A. , Palop J. A. , Goñi T. , Martinez A. , Fernández‐Alvarez E. 
Published: April 2009

AbstractThe synthesis of two new derivatives of 3H[1,2]diazepino[5,6‐b]indole, 5 and 11, and one new derivative of 3H[1,2]diazepino[4,5‐b]indole, 16, are described. Compound 5 was obtained by the reaction of methyl 2‐(3‐methoxycarbonyl‐1‐methylindole)acetate 2, with hydrazine. Compound 11 was obtained in two ways from ethyl 2‐(1‐methylindole)acetate (8) by formylation and reaction with hydrazine. Compound 16 was obtained treating 3‐(2‐ethoxycarbonylindole)acetonitrile (14) with hydrazine.
The reaction of 2‐indolecarbohydrazones with ethoxycarbonyl chloride. New synthesis of 2,3‐dihydro‐2‐oxo‐1,3,4‐oxadiazoles and 1,2,3,4‐tetrahydro‐4‐oxo‐5H‐pyridazino[4,5‐b]indoles
Authors: Monge A. , Palop J. A. , Tabar P. , Fernández‐Alvarez E. 
Published: April 2009

AbstractThe synthesis of 2,3‐dihydro‐2‐oxo‐1,3,4‐oxadiazole (4) and 5H‐pyridazino[4,5‐b]indole (7), are described. Compounds 4 were obtained by reduction of O‐ethoxycarbonylcarbohydrazones 3 with sodium borohydride. Compounds 7 were obtained by cyclization of compounds with ethanol/hydrochloric acid and removing the ethoxycarbonyl group with hydrazine. Compounds 3 were obtained by reaction of 2‐indolecarbohydrazones 1 with ethoxycarbonyl chloride.
Thiazolopyridine analogs of naldixic acid. 1. Thiazolo[5,4‐b]pyridines
Authors: Leysen D. C. , Haemers A. , Bollaert W. 
Published: April 2009

AbstractA series of 2‐substituted‐7‐alkyl‐4,7‐dihydro‐4‐oxothiazolo[5,4‐b]pyridine‐5‐carboxylic acids were synthesized. Antibacterial activity was tested in vitro. None of the new compounds prepared showed any antibacterial activity in vitro against the strains tested.
Studies on ketene and its derivatives. Part 119. Reactions of haloketenes with 2‐arylideneaminopyridines
Authors: Katagiri Nobuya , Kato Tetsuzo , Niwa Ryuji 
Published: April 2009

AbstractReactions of haloketenes with 2‐arylideneaminopyridines were examined. Reaction of dichloroketene with 2‐benzylideneaminopyridines gave 2,2‐dichloro‐3‐phenyl‐3‐(2‐pyridylamino)propanoic acids and 3‐chloro‐2‐phenylpyrido[1,2‐a]pyrimidin‐4(4H)‐ones. Similar reaction of dichloroketene with 2‐(2‐furfurylideneamino)‐pyridines gave 3‐chloro‐2‐(2‐furyl)pyrido[1,2‐a]pyrimidin‐4‐(4H)‐ones. Chloroketene and chlorophenylketene also reacted with 2‐arylideneaminopyridines to give pyrido[1,2‐a]pyrimidin‐4(4H)‐ones. Ring transformations of pyrido[1,2‐a]pyrimidin‐4‐(4H)‐ones were carried out to give 1,8‐naphthyridin‐4(1H)‐ones and imidazo[1,2‐a]‐pyridines.
Synthesis of 2,3,7,8‐tetramethoxydibenzotellurophene and its thio and seleno analogues
Authors: Engman Lars 
Published: April 2009

AbstractThe 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

AbstractEvidence, 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

AbstractUnlike 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

Abstract4‐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

AbstractStarting 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

AbstractLa 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

Abstractl'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

AbstractThe 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

AbstractA 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

AbstractThe 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

AbstractDeoxyvasicinone (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.
Molecular rearrangements of five‐membered ring heteromonocycles
Authors: L'abbé Gerrit 
Published: April 2009

AbstractMolecular 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

AbstractThe 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

AbstractIn 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

AbstractReaction 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

AbstractAn 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

AbstractThieno[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

AbstractThe 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

AbstractEthyl 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

AbstractThe 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

AbstractThe 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

AbstractIn 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

AbstractStereochemical 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

AbstractThe 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

Abstract2‐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

AbstractReactions 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

AbstractLes 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

AbstractSynthesis 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

Abstract(+)‐(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

AbstractThe 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

AbstractThe 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.