bluuebunny/crossref_metadata_2025_split huggingface dataset:
2‐amino‐4‐oxo‐6‐substituted‐pyrrolo[2,3‐d]pynmidines as potential inhibitors of thymidylate synthase
Authors: Gangjee Aleem , Yu Jianming , Kisliuk Roy L. 
Published: March 2009

AbstractClassical, antifolate inhibitors of thymidylate synthase often suffer from a number of potential disadvantages when used as antitumor agents. These include impaired uptake due to an alteration of the active transport system required for cellular uptake, as well as the formation of long acting, non‐effluxing polygluta‐mates via folypolyglutamate synthetase, which are responsible for toxicity to normal cells. To overcome some of the disadvantages of classical thymidylate synthase inhibitors, there has been considerable interest in the synthesis and evaluation of nonclassical inhibitors, which could enter cells via passive diffusion and are not substrates for folypolyglutamate synthetase. A series of eight nonclassical 6‐substituted 2‐amino‐4‐oxo‐pyrrolo[2,3‐d]pyrimidines 2a‐2h were designed as potential inhibitors of thymidylate synthase. The synthesis of the target compounds 2a‐2h was achieved via regioselective iodination at the 6‐position of 5, palladium‐catalyzed coupling with the appropriate phenylacetylenes, reduction of the C8‐C9 triple bond followed by saponification. Preliminary biological results indicated that none of the target compounds showed inhibitory activities against thymidylate synthase from Escherichia coli, Lactobacillus casei, rat or human thymidylate synthase at the concentrations tested. None of the target compounds showed inhibitory activity against dihydrofolate reductase from Escherichia coli, Lactobacillus casei, rat or human at 3.0 × 10−5 M. However, 50% inhibition of dihydrofolate reductase from Pneumocystis carinii and from Toxoplasma gondii was achieved with compound 2d and with compound 2g at 3.0 × 10−5 M.
Syntheses of substituted 2‐(2‐alkylthio‐1‐benzyl‐5‐imidazolyl)‐1,3,4‐oxadiazoles
Authors: Hadizadeh F. , Tafti F. I. 
Published: March 2009

AbstractStarting from the readily available benzylamine hydrochloride a series of 2‐(2‐alkylthio‐1‐benzyl‐5imida‐zolyl)‐1,3,4‐oxadiazoles were prepared.
Azinoiminophosphorane mediated 1,2,4‐triazole synthesis
Authors: Lee Chang Hoon , Lee Kee‐Jung 
Published: March 2009

AbstractThe aza‐Wittig reaction of benzophenone‐ or acetophenone 1‐[(triphenylphosphoranylidene)amino]‐ethylidenehydrazone (4) with aromatic aldehydes provides a new route to 1,2,4‐triazoles 7 via the thermal reaction of the expected azinoimines 5.
FInfluence of the base stoichiometry on cyclocondensation of N‐(2‐bromoethyl)phthalimide with lithium ester enolates
Authors: Calmes M. , Juan E. , Rolland M. , Martinez J. 
Published: March 2009

AbstractThe cyclocondensation of N‐(2‐bromoethyl)phthalimide with the enolate of benzyl phenyl acetate afforded two possible compounds depending on the experimental conditions used.
Studies on the chemistry of thienoannelated O,N‐ and S,N‐containing heterocycles. 25. Synthesis of new imidazolyl and pyrazolyl derivatives of thiophene as inhibitors of nitric oxide synthase
Authors: Erker Thomas , Galanski Maria E. , Galanski Mathea S. 
Published: March 2009

AbstractSome novel imidazolyl and pyrazolyl thiophene derivatives were synthesized. Different substituted N‐containing heterocycles were chosen with the aim of enhancing the activity or selectivity of the products towards inhibition of one of the three isoforms of nitric oxide synthase. One series of substances was prepared by substitution reactions of 3‐bromo‐2‐nitrothiophene with various heterocycles. In the other series introduction of a second heterocyclic substituent to pyrazolylthiophene compounds was attempted.
Studies on the reactions of cyclic oxalyl compounds with hydrazines or hydrazones : Synthesis and reactions of 4‐benzoyl‐1‐(3‐nitrophenyl)‐5‐phenyl‐1H‐pyrazole‐3‐carboxylic acid
Authors: Şener Ahmet , Kasim Şener M. , Bildmci Ishak , Kasimogullari Rahmi , Akçamur Yunus 
Published: March 2009

AbstractThe 1H‐pyrazole‐3‐carboxylic acid 2, obtained from the furan‐2,3‐dione 1 and N‐Benzylidene‐N'‐(3‐nitrophenyl) hydrazine, was converted via reactions of its acid chloride 3 with various alcohols or N‐nucleo‐philes into the corresponding ester or amide derivatives 4 or 5, respectively. Nitrile 6 and anilino‐pyrazole acid 7 derivatives of 2 were also obtained by dehydration of 5a in a mixture of SOCl2 with DMF and reduction of 2 with sodium polysulphide, respectively. While cyclocondensation reactions of 2 or 7 with phenyl hydrazine or hydrazine hydrate and 6 with only anhydrous hydrazine lead to derivatives of pyrazolo[3,4‐d]‐pyridazinone 8 and pyrazolo[3,4‐d]pyridazine amine 9, respectivel. The reaction of 2 with 2‐hydrazinopyri‐dine provided hydrazono‐pyrazole acid derivative 10, which was decarboxylated to give hydrazono‐pyra‐zole derivative 11. Pyrazolo[4,3‐d]oxazinone 12 and 2‐quinolyl pyrazolo[3,4‐d]pyridazine 13 derivatives were also prepared by cyclocondensation reactions of 2 with hydroxylamine hydrochloride and 7 with acetaldehyde, respectively.
Synthesis of 3‐alkylcarbonyloxymethyl derivatives of 5‐fluorouracil
Authors: Roberts William J. , Sloan Kenneth B. 
Published: March 2009

Abstract3‐Alkylcarbonyloxymethyl derivatives of 5‐fluorouracil have been synthesized starting with 1‐ethyloxy‐carbonyl‐5‐fluorouracil. Alkylation of the starting material with alkylcarbonyloxymethyl iodides, generated from the corresponding chlorides by the Finkelstein reaction, in the presence of 1,8‐bis(dimethyl‐amino)naphthalene followed by deprotection with 1,1‐dimethylethylamine gave good yields (50‐60%) of the target derivatives after column chromatography. A 90% yield of 3‐acetyloxymethyl‐5‐fluorouracil was obtained when the corresponding commercially available bromide was used, instead of the in situ generated iodide, and the product could be isolated from the crude reaction by crystallization. An alternate path of sequential alkylation of 5‐fluorouracil with alkylcarbonyloxymethyl chlorides in the presence of tertiary amines, exhibiting different reactivities towards the chlorides, gave an excellent yield of 1‐acetyloxymethyl‐3‐propionyloxymethyl‐5‐fluorouracil in the one instance it was attempted, but subsequent deprotection of the 1‐position with methylamine gave only a 24% yield of 3‐propionyloxymethyl‐5‐fluorouracil.
Synthesis of 4‐(trihalomethyl)dipyrimidin‐2‐ylamines from β‐alkoxy‐α,β‐unsaturated trihalomethyl ketones
Authors: Zanatta Nilo , Lopes Elizandra C. S. , Fantinel Leonardo , Bonacorso Helio G. , Martins Marcos A. P. 
Published: March 2009

AbstractThe synthesis of a novel series of twelve 4‐(trihalomethyl)dipyrimidin‐2‐ylamines, from the cyclo‐condensation reaction of 4‐(trichloromethyl)‐2‐guanidinopyrimidine, with β‐alkoxyvinyl trihalomethyl ketones, of general formula: X3C‐C(O)‐C(R2)=C(R1)‐OR, where: X = F, Cl; R = Me, Et, ‐(CH2)2‐, ‐(CH2)3‐; R1 = H, Me; R2 = H, Me, ‐(CH2)2‐, ‐(CH2)3‐, is reported. The reactions were carried out in acetonitrile under reflux for 16 hours, leading to the dipyrimidin‐2‐ylamines in 65‐90% yield. Depending on the substituents of the vinyl ketone, tetrahydropyrimidines or aromatic pyrimidine rings were obtained from the cyclization reaction. When X = Cl, elimination of the trichloromethyl group was observed during the cyclization step. The structure of 4‐(trihalomethyl)dipyrimidin‐2‐ylamines was studied in detail by 1H‐, 13C‐ and 2D‐nmr spectroscopy.
Condensation of methylhydrazine with 4‐ethoxy‐1,1,1‐trifluoro‐3‐buten‐2‐one. A reinvestigation
Authors: Pavlik James W. , Na Ayudhya Theppawut Israsena , Tantayanon Supawan 
Published: March 2009

AbstractIn contrast to previous reports, 4‐ethoxy‐1,1,1‐trifluoro‐3‐buten‐2‐one (1) was observed to react with methylhydrazine (2) in refluxing ethanol to yield 1‐methyl‐3‐(trifluoromethyl)pyrazole (6) and 4,5‐dihydro‐1‐methyl‐5‐(trifluoromethyl)pyrazol‐5‐ol (4). The later compound undergoes acid catalyzed dehydration to 1‐methyl‐5‐(trifluoromethyl)pyrazole (3).
Reactions of 1,2‐dihydro‐4H‐3,1‐benzothiazine‐2,4‐dithiones (trithioisatoic anhydrides) with N‐substituted benzylamines and trialkyl phosphites
Authors: Takahashi Masahiko , Gunji Tomoko , Ichikawa Akiko 
Published: March 2009

AbstractReactions of 1,2‐dihydro‐4H‐3,1‐benzothiazine‐2,4‐dithiones (trithioisatoic anhydrides) 3 with N‐substi‐tuted benzylamines 9 gave 1,2‐dihydroquinazoline‐4‐thiones 10, o‐thioureidodithiobenzoic acid 11, o‐aminothiobenzamides 12, 2‐amino‐3,1‐benzothiazine‐4‐thiones 13, or quinazoline‐2,4‐dithiones 14, depending on the kinds of amine and the reaction solvent. On the other hand, reaction of 3 with trialkyl phosphites afforded dialkyl (1,2‐dihydro‐2‐thioxo‐4H‐3,1‐benzothiazin‐4‐yl)phosphonates 18.
Synthesis and antimicrobial activity of novel 2‐alkyl/arylcarbamato‐6‐(1,1‐dimethylethyl)‐3‐cyclohexyl‐3,4‐dihydro‐2H‐1,3,2‐benzoxazaphosphorine‐2‐oxides
Authors: Babu Y. Hari , Reddy P. Vasu Govardhana , Reddy C. Suresh , Reddy C. Devendranath , Devi P. Uma Maheswari 
Published: March 2009

AbstractNovel 2‐alkyl/arylcarbamato‐6‐(1,1‐dimethylethyl)‐3‐cyclohexyl‐3,4‐dihydro‐2H‐1,3,2‐benzoxaza‐phosphorine‐2‐oxides (IV) have been synthesized from reactions of 2‐cyclohexylaminomethyl‐4‐t‐butylphenol I [8c] with various dichlorophosphinyl carbamates (III) [8a‐b] in dry toluene in the presence of triethylamine at 40‐50 °C. All the title compounds (IVa‐j) at reflux temperature are degraded to 2‐amino‐6‐(1,1‐dimethylethyl)‐3‐cyclohexyl‐3,4‐dihydro‐2H‐1,3,2‐benzoxazaphosphorine‐2‐oxide (IVk) exclusively. The structures are determined by ir, nmr and mass spectral studies. They were screened for antifungal activity against Penicillium notatum, Aspergillus niger and Helminthosporium sps, and antibacterial activity on Escherchia coli, Staphylococcus aureus and Pseudomonas aeruginosa. A few of them possess significant activity.
Potassium carbonate, a support for the green synthesis of azoles and diazines
Authors: Kidwai M. , Venkataramanan R. , Dave B. 
Published: March 2009

AbstractA novel potassium carbonate mediated synthesis of 2‐amino‐1,3‐thia/oxa zoles, 2‐amino‐1,3,4‐thia/oxa diazines and 2‐hydrazino‐1,3,4‐thiadiazines has been described here. The use of K2CO3 allows for an aqueous workup thereby eliminating the organic solvent from both the reaction step and post reaction stage, without compromising the yield and reaction time.
Fused‐ring nitrogen and sulfur heterocycles by a tandem SN2‐michael addition reaction
Authors: Bunce Richard A. , Kotturi Sharadsrikar V. , Peeples Christopher J. , Holt Elizabeth M. 
Published: March 2009

AbstractA tandem SN2‐Michael addition reaction has been developed for the synthesis of cis‐ and trans‐fused nitrogen and sulfur heterocycles from the cis and trans isomers of ethyl (±)‐(2E)‐3‐[2‐(iodomethyl)cyclo‐hexyl]‐2‐propenoate. Octahydro‐1H‐isoindole‐1‐acetic acid and octahydrobenzo[c]thiophene‐1‐acetic acid derivatives have been prepared and their stereochemistries elucidated using NMR and X‐ray crystallo‐graphic methods. Cyclization substrates for both the cis‐ and the trans‐fused rings are readily available in four steps from known compounds. Yields for the cyclization range from 80‐85% and stereochemical selec‐tivities with respect to the side chain vary from 12.5‐16:1 for the cis‐fused structures to 6‐7.5:1 for the trans‐fused structures. Steric interactions in the transition states for ring closure are proposed to rationalize the observed preferences.
A versatile synthesis of 2‐amino‐4H‐pyrido[1,2‐a][1,3,5]triazin‐4‐ones from 2‐aminopyridines
Authors: Kopp Marina , Lancelot Jean‐Charles , Dagdag Saïd , Miel Hugues , Rault Sylvain 
Published: March 2009

AbstractThe quasi‐one pot synthesis of new 2‐aminopyrido[1,2‐a][1,3,5]triazin‐4‐ones starting from 2‐amino‐pyridine and 2‐aminopicolines is herein described in order to obtain a library of cyclic guanidines.
Syntheses of N‐diazinyl thiocarboxamides and of thiazolodiazines. Metalation studies. Diazines XXXIII
Authors: Fruit Corinne , Turck Alain , Plé Nelly , Quéguiner Guy 
Published: March 2009

AbstractTwo thiazolodiazines were prepared from the corresponding N‐diazinylcarboxamides by use of Lawesson's reagent. Two N‐diazinylthiocarboxamides were obtained from amino derivatives by reaction with methyl phenyldithiocarboxylate. The metalation of these four compounds was studied and the thiazolodiazines could be functionalized.
Solvent‐free condensation of aromatic aldehydes and 2,3‐dimethyl‐1‐phenyl‐3‐pyrazolin‐5‐one by p‐toruenesulfonic acid
Authors: Koshima Hideko , Hamada Mitsuo 
Published: March 2009

AbstractSolvent‐free condensation easily occurred by mixing aromatic aldehydes and 2,3‐dimethyl‐1‐phenyl‐3‐pyrazoline‐5‐one (antipyrine) in the presence of p‐toluenesulfonic acid as a solid acid catalyst at room temperature to give the corresponding disubstituted products as sole products in high yields.
Novel synthesis of 2‐amino[1,4,5]benzoxadiazepine derivatives via a mild one‐pot reaction
Authors: El‐Rady Eman A. 
Published: March 2009

AbstractThe diazonium salt of 2‐aminophenol 2 was coupled in situ with malononitrile derivatives 3a‐d, 2‐cyanomethylthiazolin‐4‐one 9, 2‐cyanomethylbenzimidazole 11a, and 2‐cyanomethylbenzothiazole 11b to give 2‐amino[1,4,5]benzoxadiazepine derivatives 6a‐d, 10 and 12a,b via a one‐pot reaction.
Acid‐mediated regioselective alkylation of 1,2,3‐triazole
Authors: Korenm Andrei O. 
Published: March 2009

Abstract1,2,3‐Triazole reacts with isopropyl alcohol in concentrated sulfuric acid to yield 1‐isopropyl‐1H‐1,2,3‐triazole as the only reaction product.
Palladium catalyzed cross‐methylation of bromoheterocycles with intramolecularly stabilized dimethyl indium reagents
Authors: Jaber Nimer , Blum Jochanan , Schumann Herbert 
Published: March 2009

AbstractAlthough the intramolecularly stabilized [(3‐dimethylamino)propyl]dimethylaluminum (1a) fails to undergo palladium‐catalyzed cross‐coupling with bromopyridines and with bromofuran derivatives, the analogous gallium and indium reagent 1b and 1c smoothly cross‐methylate these and other bromoheterocycles. The cross‐coupling can be performed also with the dimeric indium and gallium compounds bis(μ‐[2‐(dimethylamino)ethanolato‐N,O:O]tetramethyldigallium and ‐diindium (2b and 2c, respectively). The indium reagent is fairly air‐stable and the reactions can be carried out under ambient conditions. The yields are generally very high but are influenced by steric and electronic effects.
Syntheses of two potential food mutagens
Authors: Tanga M. J. , Bradford W. W. , Bupp J. E. , Kozocas J. A. 
Published: March 2009

AbstractThe syntheses of the potential heterocyclic amine food mutagens l,4,6‐trimethyl‐2‐aminoimidazo[4,5‐c]‐pyridine and 1,5,7‐trimethyl‐2‐aminoimidazo[4,5‐b]pyridine are described.
Reaction of benzohydroximinoyl chlorides and β‐(trifluoromethyl)‐acetylenic esters: Synthesis of regioisomeric (trifluoromethyl)‐isoxazolecarboxylate esters and oxime addition products
Authors: Hamper Bruce C. , Leschinsky Kindrick L. 
Published: March 2009

AbstractThe triethylamine induced reaction of benzohydroximinoyl chlorides, precursors of nitrile oxides, with β‐trifluoromethylacetylenic esters gives rise to three products: 5‐trifluoromethyl‐4‐isoxozolecarboxylate esters, regioisomeric 4‐trifluoromethyl‐5‐isoxazolecarboxylate esters and an unexpected oxime 1,4‐addition adduct. Product distribution is rationalized in terms of two competing reaction modes, either 1,4 addition of the oxime anion to the acetylenic ester or formation of the nitrile oxide followed by 1,3‐dipolar cycloaddi‐tion. Anionic 1,4‐addition of the oximinoyl chloride to the acetylenic ester is preferred at low temperatures, while nitrile oxide formation followed by cycloaddition is preferred at temperatures above 0 °C. Regioisomeric products from addition of nitrile oxides to various perfluoroalkylacetylenes are compared and assigned by 13C NMR.
Studying the synthesis of 4‐tert‐butyl‐1,3‐dihydroimidazol‐2‐ones and their corresponding thiones
Authors: Loksha Yasser M. , Pedersen Erik B. , El‐Barbary Ahmed A. , El‐Badawi Mahmoud A. , Nielsen Claus 
Published: March 2009

Abstract4‐tert‐Butyl‐1,3‐dihydroimidazol‐2‐ones and 1,3‐dihydroimidazol‐2‐thiones were synthesized from 1‐amino‐3,3‐dimethylbutanone and subjected to alkylation reactions. The latter compounds were S‐alkyl‐ated with iodoacetamide under alkaline conditions. The N1 N3‐unsubstituted derivative was iodinated and subsequently alkylated with alkylation reagents which previously have been used for the synthesis of anti‐HTV active imidazoles. Unfortunately, the present products were devoid of activity against HTV.
A convenient preparation of 3‐acetyl‐5‐methylisoxazole
Authors: Sauers Ronald R. , Van Arnum Susan D. 
Published: March 2009

AbstractStarting from 2,5‐hexanedione (4), a one‐pot preparation of 3‐acetyl‐5‐methylisoxazole (1) is described. 3‐Acetyl‐5‐methylisoxazole (1) is a useful compound for the preparation of 3‐oxobutyronitrile (10) and for 3‐vinyl‐(5‐methyl isoxazolyl) ketone (2).
A simple synthesis of 5‐ethoxycarbonyl‐6‐phenyl‐1,3‐dioxin‐4‐ones and ethyl 3‐benzoyl‐4‐oxo‐2,6‐diphenylpyran‐5‐carboxylate
Authors: Şener Ahmet , Genç Hasan , Kasimşener M. , Yil Yüzüncü 
Published: March 2009

Abstract4‐Ethoxycarbonyl‐5‐phenyl‐2,3‐dihydrofuran‐2,3‐dione 1 reacts with aldehydes via the acylketene intermediate 2 giving the 1,3‐dioxin‐4‐ones 3a‐e and the 1,4‐bis(5‐ethoxycarbonyl‐4‐oxo‐6‐phenyl‐4H‐1,3‐dioxin‐2‐yl)benzene 4, and a one step reaction between dibenzoylmethane and oxalylchloride gave 3,5‐dibenzoyl‐2,6‐diphenyl‐4‐pyrone 7. The reaction of 1 with dibenzoylmethane, a dicarbonyl compound, provided ethyl 3‐benzoyl‐4‐oxo‐2,6‐diphenylpyran‐5‐carboxylate derivative 9. Compound 9 was converted into the corresponding ethyl 3‐benzoyl‐4‐hydroxy‐2,6‐diphenylpyridine‐5‐carboxylate derivative 10 via its reaction with ammonium hydroxyde solution in 1‐butanol.
A novel diacetylenic bilirubin
Authors: Tu Bilirubin Bin , Lightner David A. 
Published: March 2009

AbstractAn etiobilirubin‐IIβ analog with the central C(10) CH2 group replaced by a diacetylene unit (1) was synthesized by base‐catalyzed condensation of bis‐[3‐methyl‐4‐ethyl‐5‐formylpyrrol‐2‐yl]‐diacetylene (3) with 3‐methyl‐4‐ethyl‐5‐p‐toluenesulfonyl‐2‐pyrrolinone (10). Diacetylenic rubin 1 is a dark red solid, giving orange solutions with uv‐visible absorption maxima near 460 nm.
Palladium‐catalyzed amination with benzophenone imine as a new, safe and practical alternative to nitration for the synthesis of 7‐amino‐2,1,3‐benzothiadiazoles
Authors: Liu Yugang , Prashad Mahavir , Repič Oljan , Blacklock Thomas J. 
Published: March 2009

AbstractPalladium‐catalyzed amination of 7‐bromo‐4‐methyl‐2,1,3‐benzothiadiazole (7) with benzophenone imine as an ammonia equivalent is described as a new, safe and practical alternative to nitration for the synthesis of 7‐amino‐4‐methyl‐2,1,3‐benzothiadiazole (1) in high yield. This methodology was successfully scaled‐up in the pilot plant on 14.0‐kg scale of 7 and was also utilized for the synthesis of 7‐amino‐4,6‐dimethyl‐2,1,3‐ben‐zothiadiazole (12) by the amination of 7‐bromo‐4,6‐dimethyl‐2,1,3‐benzothiadiazole (10).
Asymmetric conjugate addition reaction using pyrazole derivatives as a chiral catalyst
Authors: Kashima Choji , Yokoyama Hiroyo , Shibata Saori , Fujisawa Kiyoshi , Nishio Takehiko 
Published: March 2009

AbstractThe conjugate addition of Grignard reagent (2) onto 1‐α,β‐unsaturated)acyl 3,5‐dimethylpyrazole (1) was enantioselectively catalyzed by the copper complex from cuprous compounds and 3‐phenyl‐l‐mentho‐pyrazole (3).
Synthesis of some furo‐thiazolidine derivatives starting from aldimines
Authors: Öcal Niiket , Aydoǧan Feray , Yolaçan Çiǧdem , Turgut Zuhal 
Published: March 2009

AbstractAlkyl and aryl substituted furothiazolidine derivatives have been synthesized by the reaction of Wittig reagent with benzylidene derivatives of 4‐thiazolidinones obtained from aldimines and thioglicolic acid.
Micowave assisted synthesis of benzo‐substituted macrocyclic diamides and their corresponding macrocyclic dithiodiamides
Authors: Elwahy Ahmed H. M. , Masaret Ghada S. 
Published: March 2009

AbstractA synthesis of a series of macrocyclic diamides 3 in good yields by reacting the corresponding bis phenols 4 with the appropriate dihalo alkanes 6 either in solvent or in dry media under microwave irradiation. Thiation of 3 with P2S5 or Lawesson's reagent in solvent free conditions under microwave irradiation is also described.
One pot diastereoselective synthesis of new chiral spiro‐1,3,4‐thiadiazoles and 1,4,2‐oxathiazoles from (1R)‐thiocamphor
Authors: Feddouli Amal , Itto Moulay Youssef Ait , Hasnaoui Aïssa , Villemin Didier , Jaffrès Paul‐Alain , Santos Jana Sopkova‐De Oliveira , Riahi Abdelkhalek , Huet FranÇOis , Daran Jean‐Claude 
Published: March 2009

AbstractHerein we report an efficient one pot synthesis of new chiral 4,5‐dihydro‐4‐arylspiro[1,3,4‐thiadiazole]‐5,2′‐camphane‐2‐carboxylic acid ethyl esters 5–7 and 4,5‐dihydro‐3‐arylspiro[1,4,2‐oxathiazole]‐5,2′‐camphane 11–13, using 1,3‐dipolar cycloaddition of nitrilimines 2–4 and nitrile oxides 8–10 to (1R)‐thiocamphor 1 respectively. The structure of the newly prepared 1,3,4‐thiadiazoles 5–7 (obtained as pure diastereoisomers) were fully established via spectroscopic analysis and X‐ray structural analysis which proved the absolute configuration of the C5 spiranic carbon to be (R). NMR spectral analysis were also very useful to show the new 1,4,2‐oxathiazoles 11–13 are mixtures of two (5R)/(5S) diastereoisomers with the ratio 6:4,7:3 and 6:4 respectively.
Structural characterization of isomeric 2,3,5‐substituted tetrahydropyrrolo[3,4‐d]isoxazole‐4,6‐diones prepared by cycloaddition of N‐methyl‐C‐arylnitrones to N‐phenyl‐ or N‐methylmaleimide
Authors: Pihlaja Kalevi , Tähtinen Petri , Shaikhutdinov Roustem , Hartikainen Heli , Ovcharenko Vladimir , Agirbas Hikmet , Güner Selahaddin 
Published: March 2009

Abstract1,3‐Dipolar cycloaddition reactions of N‐methyl‐C‐arylnitrones with N‐phenyl‐ or N‐methylmaleimide were studied. The reaction of p‐dimethylamino‐, 4‐benzyloxy‐3‐methoxy‐, p‐nitro‐ and p‐chloro‐substituted phenylnitrones with N‐phenylmaleimide gave cis and trans cycloadducts but that of the corresponding phenylnitrones with N‐methylmaleimides only the cis adducts in the case of p‐dimethylamino and 4‐benzyloxy‐3‐methoxy substitution. All cis adducts attain a biased conformation whereas the trans forms are shown (by 1H NMR at 233 K and 13C NMR at 208 K) to be mixtures of two invertomers, namely o‐(N‐lone pair antiperiplanar to 3H; minor) and i‐conformations (3H‐C‐C‐3aH dihedral angle close to 90°; major). PM3 and DFT calculations at the B3LYP/6–31G(d) level of theory prove qualitatively that these two conformers of the trans adduct are of comparable stability and represent energy minima.
On the reactivity of isoxazoles with Mo(CO)6
Authors: Donati Donato , Ferrini Serena , Fusi Stefania , Ponticelli Fabio 
Published: March 2009

AbstractRing opening with molybdenum hexacarbonyl of functionalized isoxazoles is a valuable synthetic process. Tetrazolopyridine 4 and pyrazolopyridine 9 were obtained from isoxazolopyridines 3 and 6, respectively, whereas the isoxazole 14 gave ketone 16 through the intermediate 17.
Synthesis and characterization of 2‐iminoperhydro‐1,3‐selenazin‐4‐ones by reaction of N,N'‐disubstituted selenoureas with acryloyl chloride
Authors: Koketsu Mamoru , Taura Masayasu , Ishihara Hideharu 
Published: March 2009

Abstract2‐Iminoperhydro‐1,3‐selenazin‐4‐ones were synthesized by the reaction of N,N'‐disubstituted selenoureas with acryloyl chloride.