bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of a new class of uridine phosphorylase inhibitors
Authors: Levesque Diane L. , Wang Eng‐Chi , Wei Dau‐Chang , Tzeng Cherng‐Chyi , Panzica Raymond P. , Naguib Fardos N. M. , El Kouni Mahmoud H. 
Published: March 2009

AbstractA new series of potent uridine phosphorylase inhibitors have been prepared from barbituric acid. Among them, 1‐[(2‐hydroxyethoxy)methyl]‐5‐)(m‐‐benzyloxy)benzylbarbituric acid (37, BBBA) is the most promising having a Kivalue of 1.1 ± 0.2 nMwith uridine phosphorylase from human liver. The new inhibitors are easily synthesized and are better inhibitors of human uridine phosphorylase than their uracil counterparts.
Chlorine substituent effects for indole and tryptophan in 13C NMR
Authors: Lee Minsu , Phillips Robert S. 
Published: March 2009

AbstractThe 13C and 1H nmr spectra of chloroindoles and chlorotryptophans in methanol‐d4 were assigned based on 1‐D and 2‐D nmr techniques, including COSY, inverse‐detected direct (HMQC) and long‐range (HMBC) correlation. Chlorine substitutent effects in chemical shifts (SCS) for chlorotryptophans and chloroindoles were calculated and compared. The correlations were linear except for 4‐chlorotryptophan, which suggests structural changes on the indole ring between 4‐chlorotryptophan and 4 chloroindole. The conformational analysis based on the coupling constants of the side chain also showed a change in the fractional population of the rotamers between 4‐chlorotryptophan and the other chlorotryptophans.
New routes to selectively methylated benzimidazoles
Authors: Katritzky Alan R. , Rachwal Stanislaw , Ollmann Richard 
Published: March 2009

AbstractThe use of intermediate benzotriazol‐l‐yl derivatives simplified the procedures for the preparation of 5‐methoxy‐l‐methylbenzimidazole and 6‐methoxy‐l‐methylbenzimidazole starting from 4‐methoxy‐2‐nitro‐aniline. This strategy represents a novel and potentially general method for synthesis of 5‐ and 6‐substituted‐l‐methylbenzimidazoles from 4‐substituted anilines. Preparation of l‐methyl‐5‐nitrobenzimidazole by reaction of 2‐chloro‐5‐nitroaniline with methylamine and condensation of the obtained diamine with formic acid represents a special case.
Synthesis of pyrrolo[2,1‐f][1,2,4]triazine congeners of nucleic acid purines via the N‐amination of 2‐substituted pyrroles
Authors: Patil Shirish A. , Otter Brian A. , Klein Robert S. 
Published: March 2009

AbstractThe synthesis of several new 4‐mono‐ and 2,4‐disubstituted pyrrolo[2,1‐f][1,2,4]triazines is described. Key 1‐aminopyrrole‐2‐carbonitrile intermediates 3 and 15 were obtained by N‐amination of the corresponding pyrrole‐2‐carboxaldehyde followed by CHO → CN conversion with either hydroxylamine‐O‐sulfonic acid for 3 or O‐mesitylenesulfonylhydroxylamine for 15. Cyclization of 3 or 15 with a variety of amidine reagents or, after conversion of 3 to its corresponding amide, base‐catalyzed annulation completed the synthesis of the title products.
Syntheses for 2‐hydroxy‐2H‐1,4‐benzothiazin‐3(4H)‐one derivatives as thio analogues of natural hemiacetals
Authors: Sicker Dieter , Hartenstein Holger , Hazard Roland , Tallec André 
Published: March 2009

AbstractReductive cyclizations of methyl 2‐(2‐nitrophenylthio)acetate 2 by means of electrochemistry or by catalytic hydrogenation have been used as key steps in the syntheses of the hemiacetals 2‐hydroxy‐2H‐1,4‐benzothiazin‐3(4H)‐one 10 and its 4‐hydroxy derivative 9 representing thio analogues of allelo chemicals found in Gramineae and Acanthaceae. In contrast to its natural counterpart 2,4‐dihydroxy‐2H‐1,4‐benzoxa‐zin‐3(4H)‐one hydroxamic acid 9 did not undergo degradation by extrusion of formic acid.
Chromatographic and spectroscopic properties of regioisomers of some 1H‐1,5‐benzodiazepines
Authors: Vianna‐Rodrigues S. , Martins‐Viana L. , Quiroga J. , Insuasty B. , Abonia R. , Baumann W. 
Published: March 2009

AbstractThe separation of the two regioisomeric derivatives of 1H‐1,5‐benzodiazepine yielded from the reaction of 1,2‐diamino‐4‐methylbenzene with 4‐substituted acetophenones was performed by reversed phase high performance liquid chromatography, and the absorption spectra of the separated isomers have been determined for three isomer pairs which have been obtained starting from acetophenones with substituents of different electronegativity. The isomer ratio then could be estimated as well from the ratio of the peak areas as from the absorption spectra. They agree well with the known ratio determined from nmr intensities.
Studies on pyrrolidones. Synthesis and reactivity of β‐enaminomono‐esters and β‐enaminomononitriles derived from pyroglutamic acid
Authors: Fasseur Dominique , Cauliez Pascal , Couturier Daniel , Rigo Benoît , Defretin Sebastien 
Published: March 2009

AbstractIn the pyroglutamic acid series, β‐enaminoesters 3 were formed in the 2‐position by opening of the corresponding Meldrum's derivative 6, and β‐enaminonitriles 4 were obtained by treating carbamate vinylogous 5 by trimethytsilyl iodide. Alkylation and acylation of β‐enaminoester 3a was briefly examined.
Diels‐alder reactivity of vinylsulfoxyallenes
Authors: Wang Xiaoheng , Donovalova Jana , Hollis Andrea , Johnson Dexter , Rodriguez Augusto , Kennedy G. Davon , Krishnan Ganapathy , Banks Harold 
Published: March 2009

AbstractVinylsulfoxyallenes 3a‐c are prepared from propargylic alcohols in 47‐65% yield. Vinylsulfoxyallenes undergo facile [4 + 2] cycloadditions with methyl triazolidenedione (MTAD) and singlet oxygen to afford phenylsulfinylpyridazines and spirocyclic phenylsulfinyl‐2H‐pyran‐3(6H)‐ones in excellent yields (60‐90%). Spirocyclic phenylsulfinyl‐2H‐pyran‐3(6H)‐ones are oxidized to the corresponding phenylsulfones with peracid or can be epoxidized with basic hydrogen peroxide. Spirocyclic pyranone formation is thought to proceed via the rearrangement of a labile cyclic peroxide intermediate 14.
Aminothiazole derivatives. I. A convenient synthesis of monocyclic and condensed 5‐aminothiazole derivatives
Authors: Uchikawa Osamu , Fukatsu Kohji , Aono Tetsuya 
Published: March 2009

AbstractTreatment of diamides derived from α‐amino acids with phosphorus pentasulfide or Lawesson's reagent was shown to provide a convenient method to prepare 5‐aminothiazoles. By this method, in addition to mono‐cyclic 5‐aminothiazoles 19, novel bicyclic 5‐aminothiazole derivatives such as 4,5,6,7‐tetrahydrothiazolo[5,4‐b]pyridines 11, 5,6,7,8‐tetrahydro‐4H‐thiazolo[5,4‐b]azepines 7, 4,5,6,7,8,9‐hexahydrothiazolo[5,4‐b]azocine 16 and related compounds were prepared in moderate to good yields from simple diamides, suggesting the wide versatility of the method.
3‐Oxo‐4,4,4‐trifluorobutyronitriles as building blocks of trifluoromethyl substituted heterocycles 2. Heterocyclization to 3‐aryl‐4‐trifluoromethyl‐2H‐1‐benzopyran‐2‐ones under hoesch reaction conditions
Authors: Nishiwaki Tarozaemon , Kikukawa Hirofumi 
Published: March 2009

AbstractResorcinol and 5‐methylresorcinol, respectively, react with 3‐oxo‐2‐aryl‐4,4,4‐trifluorobutyronitrile using zinc chloride as a catalyst in dibutyl ether under the Hoesch reaction conditions to give a low yield of 3‐aryl‐7‐hydoxy‐4‐trifluoromethyl‐ or 3‐aryl‐5‐hydroxy‐7‐methyl‐4‐trifluoromethyl‐2H‐l‐benzopyran‐2‐ones. However, the related reaction with m‐methoxyphenol was found to produce poor yields of 3‐aryl‐7‐methoxy‐4‐trifluoromethyl‐2H‐1‐benzopyran‐2‐one and its 3,4‐dihydro‐4‐hydroxy derivative.
Electron ionization mass spectra of some norbornane/ene‐fused 2‐N‐phenyliminoperhydro‐1,3‐oxazines
Authors: Partanen Tuula , Vainiotalo Pirjo , Stájer Géza , Pihlaja Kalevi 
Published: March 2009

AbstractThe 70 eV electron ionization (EI) mass spectra were recorded for eight norbornane/ene‐fused 2‐N‐phenyl‐iminoperhydro‐1,3‐oxazines, and the fragmentation patterns were studied by metastable ion analysis and exact mass measurement. Whereas the stereoisomeric unsaturated compounds could not be distinguished on the basis of their EI mass spectra, the stereoisomeric saturated compounds gave rise to clearly different spectra. The ionized unsaturated compounds decomposed mainly by two consecutive retro‐Diels‐Alder (RDA) reactions. A methyl substituent on the ring nitrogen strongly influenced the charge distribution on the RDA fragments. The ionized saturated compounds fragmented through several pathways. Loss of cyclopentadiene from the molecular ion was the energetically favoured fragmentation reaction for the saturated di‐endo‐fused compounds but was unimportant for the di‐exo‐fused compounds.
New thiophene derivatives as potential materials for non linear optics
Authors: Kirsch Gilbert , Prim Damien , Leising Frederic , Mignani Gerard 
Published: March 2009

AbstractA method of synthesis of unsymmetrical 2,5‐diarylthiophenes is described using β‐chloroacroleins, prepared from acetophenones, and their condensation with sodium sulfide and various benzyl bromides.
Heterocycles with a benzothiadiazepine moiety. 3. Synthesis of imidazo[5,1‐d]pyrrolo[1,2‐b][1,2,5]benzothiadiazepine 9,9‐dioxide
Authors: Silvestri Romano , Artico Marino , Pagnozzi Eugenia , Stefancich Giorgio 
Published: March 2009

AbstractThe synthesis of imidazo[5,1‐d]pyrrolo[1,2‐b][1,2,5]benzothiadiazepine 9,9‐dioxide (5), a novel sulfur‐containing tetracyclic benzodiazepine, is reported starting from pyrrolo[1,2‐b][1,2,5]benzothiadiazepine 5,5‐diox‐ide (6) by cycloaddition of tosylmethyl isocyanide to the azomethine double bond. Pyrrolobenzothiadiazepine 6 was obtained by iron powder/acetic acid reduction of 1‐(2‐nitrobenzenefulfonyl)pyrrole‐2‐carboxaldehyde (7) and subsequent ring closure of intermediate aminoaldehyde or by cyclization of 1‐(2‐formamidobenzene‐sulfonyl)pyrrole (8) with phosphorus oxychloride via a Bischler‐Napieralski reaction. Formylation of 1‐(2‐ami‐nobenzenesulfonyl)pyrrole with acetic‐formic anhydride gave 8. The structure of 5 was confirmed by oxidation with activated manganese dioxide of dihydro derivative 9, obtained through cyclization of 11‐amino‐methyl‐10,11‐dihydropyrrolo[1,2‐b][1,2,5]benzothiadiazepine 5,5‐dioxide (10) with triethyl orthoformate. The last compound was prepared alternatively by catalytic reduction of nitro derivative 11, obtained by addition of nitromethane to pyrrolobenzothiadiazepine 6, or by lithium aluminum hydride/sulfuric acid reduction of amide 13, synthesized starting from ethyl 10,11‐dihydropyrrolo[1,2‐b][1,2,5]benzothiadiazepine‐11‐carboxyl‐ate 5,5‐dioxide.
Studies on the chemistry of thienoanellated O,N‐ and S,N‐containing heterocycles. 6. Synthesis of some thienoanellated [1,4]benzoxazepines
Authors: Laimer Ingrid , Erker Thomas 
Published: March 2009

AbstractSubstituted thieno[2,3‐b][1,4]benzoxazepine derivatives as well as thieno[3,2‐b][1,4]benzoxazepine deriva‐ tives have been synthesized. They are thienoanalogues of loxapine, a potent antipsychotic drug. Research activities concentrate on the preparation of structurally modified compounds of loxapine to minimize its undesirable extrapyramidal symptoms.
Intramolecularly hydrogen‐bonded 3‐phenacyl‐lH‐pyrido[3,4‐b]‐pyrazin‐2‐one and 2‐Phenacyl‐4H‐pyrido[3,4‐b]pyrazin‐3‐one
Authors: Seki Taketsugu , Iwanami Yasuo 
Published: March 2009

AbstractTwelve phenacyl derivatives of 1H‐pyrido[3,4‐b]pyrazin‐2‐ones and 4H‐pyrido[3,4‐b]pyrazin‐3‐ones have been synthesized. In these compounds, C = N double bonds at the 3 and 4 positions in the former compounds and those at the 1 and 2 positions in the latter compounds migrate onto the side chains to form phenacyli‐dene structures. These migrations are facilitated by chelation between side chain carbonyl and the proton attached to the ring nitrogen atom which was generated by the migration. All the hydrogen‐bonded structures appear to be stable as shown by their ir spectra in the crystalline state, and by their 1H nmr spectra in solution.
The synthesis and spontaneous resolution of 2‐(2‐thioxothiazolidin‐3‐yl)thiazole
Authors: Jasmin Serge , Dalton David R. , Carroll Patrick J. , Kao Bo‐Chan 
Published: March 2009

AbstractA single crystalline enantiomer of 2‐(2‐thioxothiazolidin‐3‐yl)thiazole 5 has been isolated as the major product of the pyrolysis of 3‐(2‐thiazolin‐2‐yl)thiazolidine‐2‐thione 3 (n = 1); the latter isolated as the sole product of the reaction between thiazolidine‐2‐thione 2 (n = 1) and diethyl azodicarboxylate (DEAD) in benzene.
Studies on the synthesis of some styryl‐3‐cyano‐2(1H)‐pyridinethiones and polyfunctionally substituted 3‐aminothieno[2,3‐b]‐pyridine derivatives
Authors: Ho Yuh Wen , Wang Ing Jing 
Published: March 2009

AbstractThe 3‐cyano‐4,6‐dimethyl‐2(1H)‐pyridinethione was condensed with benzaldehyde in basic solution leads to styryl‐3‐cyano‐2(1H)‐pyridinethiones. Treatment of cinnamicaldehyde with cyanothioacetamide to give cinnamylidencyanothioacetamide, which can be cyclized with the appropriate ketones to afford the 3‐cyano‐5,6‐polymethylene‐4‐styryl‐2(1H)‐pyridinethione derivatives. The polyfunctionally substituted 3‐aminothieno[2,3‐b]pyridine derivatives were obtained in good yield by cyclization of 3‐cyano‐2(1H)‐pyridinethione derivatives with appropriate α‐halogeno carbonyl compounds and nitrile, respectively.
Some synthetic approaches to ropinirole (sk&f 101468‐a): A potent dopamine receptor agonist
Authors: Hayler J. D. , Howie S. L. B. , Giles R. G. , Negus A. , Oxley P. W. , Walsgrove T. C. , Walsh S. E. , Dagger R. E. , Fortunak J. M. , Mastrocola A. 
Published: March 2009

AbstractThree new routes to ropinirole (SK&F 101468‐A, 1) are described each involving the preparation of 3‐chlorooxindole intermediates of type 3 from β‐nitrostyrenes as the pivotal step. The superiority of sulphonate esters 17a‐c as direct precursors to 1 over the bromide 11 is also described.
Synthesis of aryl 3‐(2‐imidazolyl)propyl ketones
Authors: Davis Frank S. , Huang Liang‐Fu , Bauer Ludwig 
Published: March 2009

AbstractThe approach to the title compounds was via lithiation‐substitution of N‐methyl or N‐(triphenylmethyl)‐imidazole by some iodo ketals. 4‐Chloro‐4′‐halobutyrophenones (halo = F, Cl, Br) were converted by sodium iodide to the corresponding aliphatic iodides which were subsequently ketalized with ethylene glycol to provide the corresponding iodo ketals. Lithiation of either 1‐methyl‐ or 1‐(triphenylmethyl)imid‐azole with N‐butyllithium generated the corresponding 2‐lithioimidazoles, in situ, which were then reacted with these iodo ketals to form the corresponding C‐2 substituted imidazoles. Dilute aqueous acid hydrolysis released the ketone from the ketal. For N‐triphenylmethyl protected imidazoles, the triphenylmethyl group was also hydrolyzed to give triphenylmethanol and 3‐(2‐imidazolyl)propyl 4‐haloaryl ketones. These N‐unsubstituted imidazolyl ketones can be alkylated independently with triphenylmethyl chloride to form the corresponding N‐triphenylmethyl imidazole derivatives.
Synthesis of 2‐Substituted‐4‐carbethoxythiazoles
Authors: Kim Hong‐Seok , Kwon Il‐Cheon , Kim Oh‐Hwoan 
Published: March 2009

AbstractIn the presence of boron trifluoride etherate, aryl and alkylthioamides react with ethyl diazopyruvate to give high yields of corresponding thiazoles.
A new route to 5,6‐diarylpyridazin‐3‐ones by metalation and cross‐coupling of pyridazines
Authors: Trécourt F. , Turck A. , Plé N. , Paris A. , Quéguiner G. 
Published: March 2009

AbstractStarting from 3,6‐dichloropyridazine, a new route is described to antihypertensive 5,6‐diarylpyridazin‐3‐ones. This pathway comprises the regioselective metalation followed by a substitution of the trimethylsilyl moeity. The introduction of iodine by another metalation allowed the cross coupling of arylboronic acids. The 6‐methoxy group was then cleaved to afford the pyridazinones.
Reaction products of dialkyl acetylenedicarboxylates with 2,3‐diaminopyridine
Authors: Seki Taketsugu , Iwanami Yasuo 
Published: March 2009

AbstractThe condensation of dialkyl acetylenedicarboxylates 1 and 2 with 2,3‐diaminopyridine (3) or its 5‐bromo derivative 4 in ethanol gave pyrido[2,3‐b]pyrazinones with a common side chain ‐CH2‐COOR at their 2‐position, 5–7, but in the presence of sulfuric acid the reaction afforded their isomers with the same side chain at the 3‐position, 8–10. All of the products were shown to exist in enamine form, in which a ring double bond has been displaced onto their side chain (CHCOOR) being facilitated by an internal chelation as demonstrated by their ir and 1H nmr spectra.
Synthesis and in vitro evaluation of some new pyrimidines and related condensed ring systems as potential anticancer agents
Authors: Badawey El‐Sayed A. M. 
Published: March 2009

AbstractSeveral new pyrimidines 6–11, 18–20, furo‐, thieno‐, and pyrrolo[2,3‐d]pyrimidines 3, 8, 12, triazolo‐[4,3‐a]pyrimidines 14, 15, 16 and tetrazolo[1,5‐a]pyrimidine 17 were prepared from the known intermediate 5‐(2‐hydroxyethyl)‐6‐methyl‐2‐thiouracil (2). Compound 7 (4‐chloro‐5‐(2‐chloroethyl)‐2‐methylthio‐6‐methyl‐pyrimidine) exhibited weak antitumor activity in vitro.
Conformational analysis of 1,2,3,4‐tetrahydroisoquinolines
Authors: Ibañez Adriana F. , Moltrasio Iglesias Graciela Y. , Delfino José M. 
Published: March 2009

AbstractRing and nitrogen inversion account for the conformational equilibria of 3‐phenyl‐1, 2,3, 4‐tetrahydroiso‐quinolines. In order to quantitate the relative contribution of each conformer to the equilibrium, we undertook a molecular mechanics study on several substituted 3‐phenyl‐1, 2, 3, 4‐tetrahydroisoquinolines. Predictions from calculations were checked against cmr chemical shift data. No boat conformation contributed significantly to the equilibrium. A general result of our calculations is that in all cases the 3‐phenyl group in the equatorial position is strongly favored (by at least 2.50 kcal/mole). For 3‐phenyl‐1, 2, 3, 4‐tetrahydroisoquinolines without substitution at nitrogen, N‐H in equatorial position is preferred over the axial conformer, although the energy difference between both is always small (0.30–1.10 kcal/mole). For the cis‐1,3‐disubstituted compounds the le'3e conformers are the only species present (at least 99.8%). The calculated energy differences between the la′3a conformer and the le′3e conformer are always large (3.80–6.10 kcal/mole for the NHe conformers and 3.60–3.80 kcal/mole for the NHa conformers). The lack of a γ1a upfield shift at C3 also points to the preference for the pseudoequatorial‐equatorial conformer. For N‐methyl‐3‐phenyl‐1,2,3,4‐tetrahydroisoquinoline a preference for the NMe group in the equatorial position is predicted (0.60–2.00 kcal/mole). The small downfield shift at C4 (γNa = 0.5 ppm) is consistent with the equatorial NMe preference. For the cis‐1,2,3‐trisubstituted compounds no significant γ1a effect at C3 (γ1a = ‐0.2 and 1.0 ppm) or γNa effect at C4 (γNa = 0.1 and 0.4 ppm) is observed. For these compounds, deformations due to steric congestion are evidenced by the deviation from the values of the C4a‐C8a‐Cl‐N and C4a‐C4‐C3‐N torsional angles, as compared to less crowded 3‐phenyl‐1,2,3,4‐tetrahydroisoquinolines. Here the heterocyclic ring adopts a distorted half‐chair conformation.
Thiazolo[4,3‐c][1,4]benzodiazepines. II. Synthesis of fused[a]triazolo, tetrazolo and oxadiazolo derivatives
Authors: Gillard Alain‐Claude , Rault Sylvain , Boulouard Michel , Robba Max 
Published: March 2009

AbstractWe report the practical synthesis of the first fused[a]triazolo, tetrazolo and oxadiazolothiazolo[4,3‐c]‐[1,4]benzodiazepine‐5,11‐diones via hydrazidines and oximes.
The synthesis of 4‐benzylamino‐6‐methyl‐1H‐pyrrolo[3, 2‐c]pyridine and 4‐benzylamino‐6‐methyl‐1H‐pyrrolo[2, 3‐b]pyridine
Authors: Meade Eric A. , Beauchamp Lilia M. 
Published: March 2009

Abstract4‐Benzylamino‐6‐methyl‐1H‐pyrrolo[3,2‐c]pyridine (2) and 4‐benzylamino‐6‐methyl‐1H‐pyrrolo[2,3‐b]pyridine (3) were synthesized as deaza analogues of the anxiolytic agent 4‐benzylamino‐2‐methyl‐7H‐pyrrolo[2,3‐d]pyrimidine (1). The 1‐deaza analogue (2) was prepared via a multi‐step procedure from a pyrrole precursor, 1‐benzyl‐2‐formylpyrrole (4) while the 3‐deaza analogue 3 was synthesized from a pyridine precursor, 2‐amino‐3,6‐dimethylpyridine (12).
Synthesis of novel N‐acyclonucleosides: Benzotriazole, benzothiazinone and pyridooxazinone acyclonucleosides
Authors: Cho Su‐Dong , Chung Joo‐Wha , Kim Sung‐Kyu , Kweon Deok‐Heon , Park Ki‐Hoon , Yoon Yong‐Jin 
Published: March 2009

AbstractSome novel benzotriazole, benzothiazinone and pyridooxazinone acyclonucleosides containing 4‐hydroxybutyl, 4‐hydroxybutoxy, 4‐iodobutyl, 2‐oxopropyl and 2,3‐epoxypropoxy groups as a side chain was prepared.
Unsymmetrically substituted furoxans. Part 16 . Reaction of benzenesulfonyl substituted furoxans with ethanol and ethanethiol in basic medium
Authors: Sorba Giovanni , Ermondi Giuseppe , Fruttero Roberta , Galli Ubaldina , Gasco Alberto 
Published: March 2009

AbstractThe use of benzenesulfonyl substituted furoxans as flexible intermediates for the synthesis of new functionalized furoxans interesting for their potential biological properties is discussed. Reaction of benzenesul‐fonylphenylsulfonylfuroxan isomers 7a and 7b with ethanol and ethanethiol in basic medium affords the expected ethers and sulphides respectively. Reaction of bis(benzenesulfonyl)furoxan (1) with ethanol in basic medium gives 3‐benzenesulfonyl‐4‐ethoxyfuroxan (2) or diethoxyfuroxan (3), according to the experimental procedure. In contrast the reaction of 1 with ethanethiol gives a mixture of substitution compounds and the 4‐benzenesulfonyl‐3‐ethylthiofurazan (11). The structure of the compounds has been assigned by nmr spectroscopy and, in the case of 3‐benzenesulfonyl‐4‐ethylthiofuroxan (9b), confirmed by X‐ray analysis.
New synthesis of isoxazolidines
Authors: Malamas Michael S. , Palka Cynthia L. 
Published: March 2009

AbstractA new synthesis of 5‐substituted isoxazolidines was developed by direct isoxazolidine ring formation of allylic hydroxylamines under acidic conditions. The cyclization process is an electrophilic SN1 type reaction. The formed carbocation intermediate is stabilized by electron rich groups (i.e., phenyl). A moiety that mediates oxonium ion formation (i.e., para‐methoxy) accelerates the rate of product formation.
A facile entry to l‐aryl‐4,5‐dihydro[1,4]oxazepino‐[5,4‐a]isoindole‐2,7‐diones
Authors: Warawa E. J. , Ceccarelli C. 
Published: March 2009

AbstractThe titled compounds were prepared by reacting N‐(2‐bromoethyl)phthalimide with enolates of phenylacetic acid esters. 2,3‐Dihydrooxazolo[2,3‐a]isoindolones are believed to be intermediates in the process. An X‐ray crystallographic analysis was conducted on one of the compounds.
Pyridine Syntheses. II. Condensation Routes Toward Streptonigrin Ring C
Authors: Robinson J. Michael , Ahmed Masood , Alaniz Nicky J. , Boyles Timothy R. , Brasher Chris D. , Floyd Kimberly A. , Holland Preston L. , Maruffo Laura D. , Mcmahan Terry L. , Middleton Stan , O'Hara Kevin D. , Pack Marcia J. , Reynolds Brandon D. , Rodriquez Romelia R. , Sawyer Dennis E. , Sharp Elena , Simpson Sharai L. , Vanlandingham Clint L. , Velasquez Rebecca S. , Welch Brian M. , Wright C. David 
Published: March 2009

AbstractAlternative complimentary syntheses of penta‐substituted pyridine rings with full regiochemical control of substituents were studied as a method for the synthesis of Streptonigrin (1). Various α‐substituted acetophenones 2 were reacted with enones 3 in acetic acid/ammonium acetate and air to afford penta‐substituted pyridines 4. α‐Substituents that could provide a source of exocyclic nitrogen at position 3 of these Steptonigrin ring‐C models proved to be the limiting factor. However, an inverse “3+2+1” cyclocondensation of α‐cyanochalcone 5c with 2‐furyl ethyl ketone (6b) afforded the desired model 6‐(2‐furyl)‐5‐methyl2,4‐diphenyl‐3‐pyridinecarbonitrile (4g) in 75% yield.