bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of 6H‐pyrazolo[2,3‐a][1,3,5]benzotriazepines
Authors: Peet Norton P. , Sunder Shyam , Barbuch Robert J. 
Published: March 2009

AbstractTreatment of 5‐amino‐1‐(2‐aminophenyl)‐1H‐pyrazole‐4‐carbonitrile (15) with triethyl orthoformate produces 6H‐pyrazolo[2,3‐a][1,3,5]benzotriazepine‐3‐carbonitrile (16). Other members of this novel ring system result from treating 15 with triethyl orthoacetate and triethyl orthopropionate. These latter reactions, which yield homologs 17 and 19, respectively, of 16, also produce acyclic Schiff bases. These Schiff bases are useful in determining the position of the triazepine double bond in pyrazolobenzotriazepines 16,17 and 19, using 13C nmr spectroscopy.
1,3‐Dipolar cycloaddition of nitrones with α,β‐unsaturated sulfones
Authors: Dalla Croce Piero , La Rosa Concetta , Stradi Riccardo , Ballabio Marzia 
Published: March 2009

AbstractC,N‐Diphenyl nitrones react with substituted α,β‐unsaturated phenylsulfones yielding isoxazolidinic cycloadducts whose structure and stereochemistry were assigned on the basis of 1H and 13C nmr data. The ycloaddition regioselectivity is discussed in accordance with frontier orbital considerations.
Selenium‐Sulfur analogs. 6. Selenoisosteres of levamisole
Authors: Jones Gerald S. , Hanson Robert N. , Davis Michael A. 
Published: March 2009

AbstractA series of three new isosteres of levamisole was prepared by the substitution of the phenyl ring by the thienyl and selenienyl moieties and of the thiazole group by selenazole. The physiochemical properties and infrared spectra of the sulfur‐ and selenium‐containing analogs were very similar. Differentiation was mostapparent in the nuclear magnetic resonance spectra where the α‐ and β‐protons of the selenienyl compounds were shifted downfield relative to those of the corresponding thienyl compounds. With deuterated thiofluoroacetic acid as the solvent, a more rapid exchange was observed for the α‐proton of the selenienyl ring of compounds 17 and 18 compared to that observed for compound 16.
Reaction of ketenes with N,N‐disubstituted α‐aminomethyleneketones. XIII. Synthesis of 2H‐pyrano[3,2‐d]‐1‐benzoxepin derivatives
Authors: Menozzi Giulia , Mosti Luisa , Schenone Pietro 
Published: March 2009

AbstractCycloaddition of dichloroketone to N,N‐disubstituted (E)‐4‐aminomethylene‐3,4‐dihydro‐1‐benzoxepin‐5(2H)‐ones gave N,N‐disubstituted 4‐amino‐3,3‐dichloro‐3,4,5,6‐tetrahydro‐2H‐pyrano[3,2‐d]‐1‐benzoxepin‐2‐ones II, which are derivatives of the new heterocyclic system 2H‐pyrano[3,2‐d]‐1‐benzoxepin. Dehydrochlorination with triethylamine of II afforded N,N‐disubstituted 4‐amino‐3‐chloro‐5,6‐dihydro‐2H‐pyrano‐[3,2‐d]‐1‐benzoxepin‐2‐ones III in good to moderate yields. In the triethylamine treatment of IIh (NR2 = diphenylamino), 3‐chloro‐5,6‐dihydro‐2H‐pyrano[3,2‐d]‐1‐benzoxepin‐2‐one was isolated in low yield near to IIIh, whereas IIc (NR2 = diisopropylamino) gave in low yield 4‐diisopropylamino‐5,6‐dihydro‐2H‐pyrano(3,2‐d)‐1‐benzoxepin‐2‐one.
Synthesis of some 5,6,7,8‐tetrahydro‐4‐cinnolone derivatives and 1‐methyl‐3‐arylacetyl‐4,5,6,7‐tetrahydroindazoles
Authors: Gelin Suzanne , Dolmazon René 
Published: March 2009

Abstract2‐Arylidene‐3‐oxo‐2,3,4,5,6,7‐hexahydrobenzo[b]furans 2 react with hydrazine hydrate to afford 5,6,7,8‐tetrahydro‐4‐cinnolones. By methylation, these compounds gave the corresponding N‐1 and N‐2 methyl derivatives. The mesoionic compounds are obtained, accompanied by 3‐arylacetyl‐4,5,6,7‐tetrahydroindazoles upon reaction of 2 with methylhydrazine.
Structural resolution of the stereochemistry of a spirooxirane derived from an α‐arylidene heterocyclic carbonyl. The crystal and molecular structure of 2‐(p‐chlorophenyl)‐5‐phenyl‐7‐methyl‐1‐oxa‐5,6‐diazaspiro[2.4]hept‐6‐en‐4‐one
Authors: Baker Ronald J. , Lankin David C. , Umrigar Pesi P. , Griffin Gary W. , Ege Seyhan N. , Ragone Katherine S. , Trefonas Louis M. 
Published: March 2009

AbstractThe stereochemical assignment of molecular geometry for α‐arylidene carbonyl compounds and spirooxirane derived from them have continued to be a challenging problem for which the most satisfactory solution continues to be an x‐ray diffraction structure determination. In that regard, the title compound (a spirooxirane) has been found to crystallize in the monoclinic space group P21/c with cell dimensions of a = 5.989(1)Å, b = 27.625(4)Å, c = 9.374(2)Å, β = 99.06(1)°. The structure of the compound has been determined, with the refinement to R = 0.059. The previous, tentative assignment of structure has been confirmed substantiating our prediction that the oxidation of the enone system proceeds with rotation of the phenyl group on the β‐carbon away from the carbonyl group, minimizing adverse steric interactions and allowing orbitals of the carbonyl group to overlap with those of the carbanionic center during the closure of the oxirane ring. The agreement between predictions based on nmr data and the x‐ray diffraction determination will support a stronger reliance on the nmr data predictions in subsequent studies.
Synthèse et transformations de pyridopyrimidopyrimidines
Authors: Kokel Bruno , Guillaumel Jean , Royer René 
Published: March 2009

AbstractPlusieurs pyridopyrimidopyrimidines et une pyrimidopyrimidoisoquinoléine sont élaborées par action de pyridines diversement substitutés ou de l'isoquinoléine sur le produit de condensation de l'amino‐4 diméthyl‐1,3 uracile et du chlorure de N‐diméthyl phosgèneiminium. Ces composés se prětent aisément à de nombreuses transformations.
Synthesis of some pyrrolobenzothiazepines via N‐aryl‐2‐thiocyanatopyrroles
Authors: Cheeseman G. W. H. , Hawi A. A. 
Published: March 2009

AbstractPyrrolo[1,2‐a[3,1]benzothiazepines were successfully synthesized from alkylthiopyrroles. The latter compounds were prepared from the appropriate N‐aryl‐2‐thiocyanopyrroles. 2,3‐Dihydro‐3‐oxo‐4‐phenylthieno[3,2‐b]pyrrole (29) was obtained from acid treatment of the 2‐pyrrolylthioacetic acid 28.
Reaction of 4‐methylene‐5(4H)‐oxazolones with diazomethane
Authors: Arenal I. , Bernabé M. , Alvarez E. Fernández , Izquierdo M. L. , Penadés S. 
Published: March 2009

AbstractThe reaction of diazomethane with some (E) and (Z)‐2‐substituted‐4‐methylene‐5(4)‐oxazolones (1a‐c) under two different conditions, has been studied. (E) and (Z)‐1,2‐disubstituted‐7‐oxo‐6‐oxa‐4‐azaspiro[2.4]‐hept‐4‐enes (3a‐c, 4a‐c) were mainly obtained, together with multiple addition compounds. The reaction showed to be stereoselective only when the substituents were aromatic. Acid hydrolysis of compounds 3a and 4a produced a mixture of (E) and (Z)‐3,5‐disubstituted‐tetrahydrofuran‐2‐ones (8a, 9a). Smooth methanolysis of the ring led to (E) and (Z)‐1‐benzamido‐cyclopropanecarboxylic esters (10a‐c, 11a‐c), which, on acid hydrolysis, gave (E) and (Z)‐1‐amino‐2‐phenylcyclopropanecarboxylic acids 12a and 13a. The pmr spectra have been analyzed by an iterative computer method, and the computed best values obtained have been used to deduce the stereochemistry of the spiroderivatives.
Stereochemistry and 13C NMR investigation of 9‐halotetrahydro‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones
Authors: Tóth Gábor , Hermecz István , Breining Tibor , Mészáros Zoltán , Bitter István 
Published: March 2009

AbstractIt was shown that the halogen atom occupies the quasi‐axial position in the predominant conformer of the 9‐halo derivatives of tetrahydro‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones. When R3 = Me, the conformational equilibrium is determined by the latter substituent which is always quasi‐axial. The effects of the methyl group and the halogen atoms on the 13C chemical shifts (SCS values) were used for the identification of cis and trans isomers. Interesting non additivity of substituent effects was found in derivatives bearing quasi‐axial substituents at C‐6 and C‐9: and this was caused by the ring flattening.
Reaction of 2‐dimethylaminomethylene‐1,3‐diones with dinucleophiles. II. Synthesis of 5‐(alkyl)(phenyl)‐4‐acylisoxazoles and 6,7‐dihydro‐1,2‐benzisoxazol‐4(5H)‐ones
Authors: Menozzi Giulia , Schenone Pietro , Mosti Luisa 
Published: March 2009

AbstractThe reaction of open‐chain and cyclohexane sym‐2‐dimethylaminomethylene‐1,3‐diones with hydroxylamine hydrochloride in refluxing methanol gave in good to moderate yields a series of 5‐(alkyl)(phenyl)‐4‐acylisoxazoles and 6,7‐dihydro‐1,2‐benzisoxazol‐4(5H)‐ones, respectively. As 3‐unsubstituted isoxazoles, all these compounds easily isomerized with sodium methoxide to the corresponding 2‐cyano‐1,3‐diones in high yields.
Reaction of 2‐dimethylaminomethylene‐1,3‐diones with dinucleophiles. III. Synthesis of 5‐acylpyrimidines and 7,8‐dihydroquinazolin‐5(6H)‐ones
Authors: Mosti Luisa , Menozzi Giulia , Schenone Pietro 
Published: March 2009

AbstractThe reaction of open‐chain and cyclohexane sym‐2‐dimethylaminomethylene‐1,3‐diones with amidines and guanidine in refluxing ethanol gave, generally in good yields, a series of 5‐acylpyrimidines and 7,8‐dihydroquinazolin‐5(6H)‐ones, respectively. With formamidine (and in part acetamidine), 2‐formylimino‐1,3‐diones were formed in general, as sole products or mixtures with the corresponding pyrimidines or dihydroquinazolinones.
Addition photochimique d'azidoformiate d'alkyle sur le méthylène‐2 tétrahydropyranne et le méthoxy‐2 dihydro‐5,6 γ‐pyranne
Authors: Kozlowska‐Gramsz Elzbieta , Descotes Gérard 
Published: March 2009

AbstractLa régiosélectivité et la stéréosélectivité de l'addition photochimique des nitrènes et de l'alcoolyse ou de l'hydrolyse des aziridines intermédiaires sont étudiées sur 1 et 2. Ces réactions sont régiospécifiques et fortement stéréosélectives pour conduire à des aminocétals ou des aminocétals dont les structures ont été établies.
Voies d'accès à un analogue pyrannique de la puromycine
Authors: Carret Geneviève , Sarda Nicole , Abou‐Assali Mounir , Anker Daniel , Pachéco Henri 
Published: March 2009

AbstractL'obtention de l'analogue pyrannique 3 de la puromycine 1 via l'aminonucleoside 4 est réalisée à partir des anhydro‐2,3‐désoxy‐4‐α et β‐D,L‐érythro‐pentopyranosides de méthyle (12). La première voie consiste à introduire la fonction amine et à réaliser les isomérisations nécessaires à l'obtention de la stéréochimie érythro de la partie osidique avant de réaliser la liaison N‐glycosidique avec la purine; elle comporte 9 étapes pour arriver à l'aminonucleoside 4 (34% à partir de 12β). Par la deuxième voie, on réalise les modifications chimiques et structurales de la partie osidique après la création de la liaison N‐glycosidique; cette deuxième voie comporte 9 étapes (37% à partir du mélange 12α et 12β).L'introduction de la L‐O‐méthyltyrosine convenablement protégée est réalisée par le “BOP” et les deux diastéréoisomères obtenus conduisent après déblocage, aux deux diastéréoisomères cherchés 3A et 3B qui sont séparés sur colonne de gel de silice.
Racematspaltung von (±)‐5‐äthyl‐1‐(3,4‐dimethoxyphenyl)‐6,7‐dimethoxy‐4‐methyl‐5H‐2,3‐benzodiazepin und anomales chiroptisches verhalten der enantiomeren
Authors: Tóth Gábor , Fogassy Elemér , Ács Mária , Töke László , Láng Tibor 
Published: March 2009

AbstractEs wurde ein Verfahren für die Racematspaltung von 1 entwickelt. Das anomale Verhalten des spezifischen optischen Drehungsvermögen der Enantiomere wurde untersucht, und es wurde bewiesen, dass es nicht auf die Epimerisation des C‐5 Atoms, sondern auf die Verschiebung des Konformationsgleichge‐wichtes 1a ← 1b zurückzuführen ist.
A facile synthesis of 1,3,4‐selenadiazolo[2,3‐b]quinazoline derivatives via japp‐klingemann reaction
Authors: Abdelhamid Abdou O. , Hassaneen Hamdi M. , Shawali Ahmad S. 
Published: March 2009

AbstractDiazotized anthranilic acid and its methyl ester react with ethyl α‐selenocyanatoacetate 3a and α‐selenocyanatoacetoacetanilide 3b to give in both cases the corresponding 1,3,4‐selenadiazolo[2,3‐b]quinazoline derivatives 7a and 7b, respectively, in good yields (70‐80%). A mechanism is proposed and it is substantiated by an alternate synthesis of 7a and 7b from the corresponding hydrazidoyl chlorides 9a and 9b with potassium selenocyanate, respectively. An evidence for the involvement of the 1,3,4‐selenadiazoline derivative as an intermediate in these reactions is provided by the isolation of 11 from either coupling of 3b with diazotized ethyl p‐aminobenzoate or the reaction of hydrazidoyl chloride 12 with potassium selenocyanate.
On the possibility of isolating diazirine N‐oxides
Authors: Boyd Russell J. , Gupta Abha 
Published: March 2009

AbstractAb initio molecular orbital calculations at the 6‐31G level predict that diazirine N‐oxide is more stable with respect to its constituent fragments, singlet CH2 and N2O2, than diazirine is with respect to singlet CH2 and N2. In view of these results and the many diazirines which have been reported, it is suggested that it may be possible to detect a suitably substituted diazirine N‐oxide.
Synthesis of 2‐arylpyrido[3,4‐b]pyrazine derivatives through condensation of 3,4‐diaminopyridine with β‐keto sulfoxides
Authors: Kano Shinzo , Yuasa Yoko 
Published: March 2009

AbstractThe reaction between 3,4‐diaminopyridine and α‐methylsulfinylacetophenone in benzene containing acetic acid under reflux gave 2‐phenylpyrido[3,4‐b]pyrazine. In this way, 2‐(4‐methoxyphenyl)pyrido[3,4‐b]‐pyrazine and 2‐(3,4‐dimethoxyphenyl)pyrido[3,4‐b]pyrazine were obtained by condensation of 3,4‐diaminopyridine with the corresponding α‐methylsulfinylacetophenones.
Facile synthesis of N‐substituted‐4‐cyano‐4‐phenylpiperidines via phase‐transfer catalysis
Authors: Thompson Doug , Reeves Perry C. 
Published: March 2009

AbstractPhenylacetonitrile can be condensed with N‐substituted‐bis(2‐chloroethyl)amines in aqueous sodium hydroxide solution to produce N‐substituted‐4‐cyano‐4‐phenylpiperidines. Hexadecyltributylphosphonium bromide is an effective catalyst for this phase‐transfer reaction.
Selective synthesis of the two diastereomers of 5‐oxo‐1H‐pyrrolizine‐3‐carboxylic acid
Authors: Turner William W. 
Published: March 2009

AbstractThe rhodium catalysed reduction of a 2,5‐disubstitued pyrrole 5 occurred selectively with the cis addition of hydrogen. The resulting cis‐pyrrolidine was either cyclized without epimerization in refluxing toluene to the pyrrolizine 7 or with epimerization in refluxing acetic acid to the pyrrolizine 9.
On the formation of “symmetrical” phenoxazinone derivative related to the actinomycin D chromophore
Authors: Sehgal Raj K. , Sengupta Sisir K. , Dieter R. Karl 
Published: March 2009

AbstractIn studies related to the synthesis of 2‐deamino chromophores of actinomycin by reaction of nitrous acid in fluoroboric acid via diazotization of the 2‐amino group in the chromophore, the unknown fluorescent product is identified as the symmetrical phenoxazinone by cmr and pmr.
Synthesis of 6‐arylazo‐substituted 5‐hydroxy‐2‐hydroxymethyl‐4‐pyridones and related compounds
Authors: Imafuku Kimiaki , Matsuura Hiromichi 
Published: March 2009

Abstract5‐Hydroxy‐2‐hydroxymethyl‐4‐pyridone (1) and 5‐hydroxy‐2‐hydroxymethyl‐1‐methyl‐4‐pyridone (2) reacted with arenediazonium salts to give 6‐arylazo‐substituted compounds 3a‐d and 4a‐d, respectively. Compounds 3a‐d were methylated with diazomethane to afford 6‐arylazo‐2‐hydroxymethyl‐4,5‐dimethoxypyridines 5a‐d.
Ring transformation reactions of C‐nucleosides: Facile synthesis of pyrazolo[1,5‐a]pyrimidine and pyrazolo[1,5‐a]triazine C‐nucleosides
Authors: Chu C. K. , Suh J. J. , Mesbah M. , Cutler S. J. 
Published: March 2009

Abstract1,3‐Dimethyluracil (1), a versatile synthon for the synthesis of various heterocycles, reacted readily with 3‐aminopyrazoles 2 in sodium ethoxide to give pyrazolo[1,5‐a]pyrimidines 3. Under similar conditions, 3‐aminopyrazole C‐nucleosides 4 and the synthon 1 gave a mixture of pyrazolo[1,5‐a]pyrimidine C‐nucleosides, which was separated on a silica gel column. Attempts to remove the protecting groups yielded pyranose derivative 10. Another synthon 1,3‐dimethyl‐5‐azauracil and 3‐aminopyrazoles 12 gave pyrazolo[1,5‐a]triazines 13. In a similar reaction with 3‐aminopyrazole C‐nucleosides 4 gave the corresponding pyrazolo[1,5‐a]‐triazine C‐nucleosides 14 and 15.
Synthesis of substituted pyrrolo[1,2‐a][1,3]diazepine. A correction
Authors: Zimmermann Werner , Sinambela James M. , Roth Herman J. , Eger Kurt 
Published: March 2009

AbstractThe structure of a formerly described pyrrol[1,2‐a][1,3]diazepine is corrected by synthesis. The correction is discussed by comparing physicochemical data and synthetic procedures for both substances.
Novel syntheses of 3‐cyano‐3,4‐dihydroquinolin‐2(1H)‐one and derivatives of 2,3‐dicarbomethoxy‐2‐hydroxycyclopenta[b]quinoline
Authors: Neelima  , Bhat Balkrishen , Bhaduri Amiya Prasad 
Published: March 2009

AbstractA facile solid phase conversion of 2‐chloro‐3‐cyano‐4‐substituted‐1,4‐dihydroquinolines to 3‐cyano‐4‐substituted‐3,4‐dihydroquinolin‐2(1H)‐ones in almost quantitative yields and a novel synthesis of 2,3‐dicarbomethoxy‐2‐hydroxycyclopenta[b]quinoline are described.
Benzohydrazides, benzothiohydrazides, and benzamidrazones as sources of 1,3,4(2H)‐oxadiazolenones, 1,3,4(2H)‐thiadiazolenones, and 1,2,4(5H)‐triazolenones
Authors: Barnish Ian T. , Fung Shing C. , Gibson Martin S. , Khan Saeed R. , Pawalchak Gordon A. , Tse Kin M. 
Published: March 2009

AbstractBenzohydrazides, benzothiohydrazides, and benzamidrazones have been converted to 1,3,4(2H)‐oxadiazolenones, 1,3,4(2H)‐thiadiazolenenones, and 1,2,4(5H)‐triazolenones respectively by reaction with ethyl chloroformate, with ethyl thiolchloroformate, and with phenyl isocyanate. In some reactions, a carbamate or urea has been isolated as intermediate.
Solid‐state structures of cis‐ and trans‐1‐cyclohexyl‐2‐phenyl‐3‐(p‐toluyl)aziridines
Authors: Tarburton John Philip , Day Cynthia S. , Day Victor W. , Tavaniepour Iraj , Cromwell Norman H. 
Published: March 2009

AbstractSolid‐state structures have been determined for cis‐ and trans‐1‐cyclohexyl‐2‐phenyl‐3‐(p‐toluyl)aziridines using single‐crystal X‐ray diffraction techniques. The cis isomer crystallizes in the centrosymmetric monoclinic space group P21/c (No. 14), with a = 18.669(3)Å, b = 5.709(1)Å, c = 17.412(2)Å, β = 96.29(1)° and Z = 4; the trans isomer crystallizes in the noncentrosymmetric orthorhombic space group Pna21 (No. 33), with a = 17.089(2)Å, b = 18.729(3)Å, c = 5.749(1)Å and Z = 4. Full‐matrix least‐squares refinement of the structural parameters led to the following final agreement factors: R1 (unweighted, based on F) = 0.040 and R2 (weighted, based on F) = 0.054 for the 2592 independent reflections of the cis isomer having 2θMoK¯α <55° and I>3σ1, and R1 = 0.033 and R2 = 0.031 for the 1504 independent reflections of the trans isomer having 2θMoK¯α <55° and I>3σ1. The statistically significant differences that exist between the two isomers for two bond lengths and ten bond angles (p < 0.05) appear to be the direct result of the p‐toluyl group orientation with respect to the cyclohexyl and phenyl substituents. In the cis isomer it is anti with respect to the N‐cyclohexyl group and cis with respect to the phenyl group, whereas in the trans isomer it is syn with respect to the N‐cyclohexyl and trans with respect to the phenyl group. Three‐ring to carbonyl hyperconjugation is correlated with stereoelectronic interactions in the trans isomer. Bonding, determined by X‐ray and nmr studies, is discussed for the three‐membered aziridine ring proper; while bonding, determined by X‐ray studies, is discussed for substituents of the aziridine ring. These aziridinyl ketone compounds are of importance as potential mammalian DNA alkylating anti‐tumor agents in solid‐state solid‐state systems. To date only a trans isomer has demonstrated this biological activity in tumor‐bearing rats.
Mass spectral study of 2‐aryl‐4‐arylhydrazono‐4,5,6,7‐tetrahydro‐2H‐benzo‐1,2,3‐triazoles
Authors: Lefkopoulou S. , Theodosiou M. , Stephanidou‐Stephanatou J. , Alexandrou N. E. 
Published: March 2009

AbstractThe mass spectra upon electron impact at 70 eV of the title compounds are examined. The fragmentation pattern of the tetrahydro‐benzotriazoles with unsymmetrically substituted the aryl groups in 2‐position and in hydrazone group cannot support the aspect for a mononuclear heterocyclic rearrangement.
Reaction of ketenes with N,N‐disubstituted α‐aminomethyleneketones. XVII. Synthesis of 2H‐[1]benzothiepino[5,4‐b]pyran derivatives
Authors: Menozzi Giulia , Mosti Luisa , Schenone Pietro 
Published: March 2009

Abstract1,4‐Cycloaddition of dichloroketene to a number of N,N‐disubstituted (E)‐4‐amino methylene‐3,4‐dihydro‐[1]benzothiepin‐5(2H)‐ones gave in excellent yield N,N‐disubstituted 4‐amino‐3,3‐dichloro‐3,4,5,6‐tetrahydro‐2H‐[1]benzothiepino[5,4‐b]pyran‐2‐ones III, which are derivatives of the 2H‐[1]benzothiepino[5,4‐b]pyran system. Dehydrochlorination of III with DBN afforded N,N‐disubstituted 4‐amino‐3‐chloro‐5,6‐dihydro‐2H‐[1]‐benzothiepino[5,4‐b]pyran‐2‐ones, generally in excellent yield.
Studies directed toward the synthesis of conformationally restricted neurotransmitter analogs: The addition of N‐hydroxyimides to ethyl propiolate
Authors: Breaux E. Jay 
Published: March 2009

AbstractN‐Hydroxyimides were found to add readily to ethyl propiolate to yield the imidooxyacrylates in both protic and aprotic solvents. The trans isomer only was formed in aprotic solvents while both isomers were formed in protic solvents.
Chemical reactions of cycloalkanespirohydantoins. Part 3. Acid‐catalyzed reaction of 4‐hydroxy‐2‐imidazolidinones. Preparation of bis(1,3‐diaza‐2‐oxospiro[4,5]decyl‐4) ether
Authors: Pedregal Carmen , Espada Modesta , Salazar Loreto , Elguero José 
Published: March 2009

AbstractThe use of N‐carbamoyliminium ion initiated reactions for the generation of spiroimidazolidin‐2‐ones has been successfully exploited. N3‐Substituted‐4‐hydroxy‐2‐imidazolidinones have been treated under acid conditions to give the rearranged imidazolinones. Only in the case of N3‐dialkylaminomethyl‐4‐hydroxy‐5‐cyclohexanespiro‐2‐imidazolidinones upon treatment with trifluoroacetic anhydride/trifluoroacetic acid afforded a mixture containing bis(1,3‐diaza‐2‐oxospiro[4,5]decyl‐4) ether with the rearranged imidazolidinone.
Preparation of 5,5‐dicyano‐ and 5‐cyano‐5‐ethoxycarbonyl‐5,6‐dihydro‐3,7‐diphenyl‐4H‐1,2‐diazepines and their halogenations
Authors: Kamata Kichinosuke , Tsuge Otohiko 
Published: March 2009

Abstract5,5‐Dicyano‐ and 5‐cyano‐5‐ethoxycarbonyl‐5,6‐dihydro‐3,7‐diphenyl‐4H‐1,2‐diazepines were prepared by the condensation of α‐bromoacetophenone azine with malononitrile and ethyl cyanoacetate in the presence of sodium ethoxide, respectively. Halogenations of the dihydrodiazepines gave pyridazines, diazanorcaradienes, 4,4,6,6‐tetrachlorodihydrodiazepines, and/or a 4‐chloropyrazole whose relative yields strongly depended upon the nature of 5‐substituents of the dihydrodiazepines as well as the reaction conditions.
2‐Alkoxy‐3‐substituted‐4‐quinolinols from the thermal reactions of N‐phenylketenimines bearing ester groups
Authors: Motoyoshiya Jiro , Takagi Akira , Hirakawa Kiyoichi , Kakurai Toshio 
Published: March 2009

AbstractSeveral ketenimines bearing ester groups were prepared and their thermal reactions gave 2‐alkoxy‐3‐substituted‐4‐quinolinols VIa‐e via presumed iminoketene intermediates. Subsequent oxidation of 2‐alkoxy‐3‐(3‐methylbut‐2‐enyl)‐4‐quinolinols VIc and VId provided pyranoquinolines VIIIa and VIIIb.