bluuebunny/crossref_metadata_2025_split huggingface dataset:
ω‐Dialkylaminoalkyl ethers of phenyl‐(5‐substituted 1‐phenyl‐1H‐pyrazol‐4‐yl)methanols with analgesic and anti‐inflammatory activity
Authors: Menozzi Giulia , Mosti Luisa , Fossa Paola , Mattioli Francesca , Ghia Marco 
Published: April 2009

AbstractA series of carbinols 3a‐f was prepared starting from methanols 1a‐f via oxidation with pyridinium chlorochromate to aldehydes 2a‐f, followed by a Grignard reaction of the latter. Reaction of 3a‐f with ω‐chloroalkyldialkylamine hydrochlorides afforded a series of aminoether derivatives 4g‐t. Compounds 4i,m‐p,s showed a good analgesic activity in the acetic acid writhing test in mice. Moreover, compounds 4h,1,s exhibited a moderate anti‐inflammatory activity in the carrageenan‐induced edema assay in rats.
Methanetricarboxylates as key reagents for the simple preparation of heteroarylcarboxamides with potential biological activity. Part 1 reaction of methanetricarboxylates with indoline and 1,2,3,4‐tetrahydroquinoline
Authors: Kutyrev Alexander , Kappe Thomas 
Published: April 2009

AbstractThe reaction of methanetricarboxylates 2a,b with indoline as well as 1,2,3,4‐tetrahydroquinoline yields tricyclic 4‐hydroxy‐2(1H)‐quinolones with an ester group in position 3 (3, 8a,b). These heterocyclic esters condense with primary aliphatic, aromatic, and heteroaromatic amines to give the corresponding amides 5a‐e and 10a‐t.
A built‐in route leading to a self‐inclusion complex of 6A,6B‐(bis‐O‐p‐allyloxyphenyl)hexakis(2,3‐di‐O‐methyl)‐α‐cyclodextrin
Authors: Chen Zhen , Bradshaw Jerald S. , Habata Yoichi , Lee Milton L. 
Published: April 2009

AbstractHexakis(2,3‐di‐O‐methyl)‐α‐cyclodextrin was treated with 2,4‐dimethoxybenzene‐1,5‐disulfonyl chloride to give 6A,6B‐di‐O‐sulfonated product 5 in only a 3.0% yield. When treated with sodium p‐allyloxyphenoxide, 5 gave 6A,6B‐(bis‐O‐p‐allyloxyphenyl)hexakis(2,3‐di‐O‐methyl)‐α‐cyclodextrin (6) in a 57% yield. A careful 1H nmr analysis of 6 shows that one of the allyloxphenyl groups is in the α‐cyclodextrin cavity. This is the first intramolecular complex formed from a modified α‐cyclodextrin. Molecular modeling was used to explain the experimental facts. A novel built‐in route leading to a self‐inclusion α‐cyclodextrin complex is proposed for this reaction.
Thermal reactions of 2‐(2‐oxo‐3‐nitro‐4‐quinolinyl)malonates
Authors: Täubl A. Elisabeth , Stadlbauer Wolfgang 
Published: April 2009

AbstractDepending on the ester substituent, diethyl 2‐(3‐nitro‐2‐oxo‐4‐quinolinyl)malonates 2 give upon thermolysis ethyl 2‐(3‐nitro‐2‐oxo‐4‐quinolinyl)acetates 4, whereas dimethyl 2‐(3‐nitro‐2‐oxo‐4‐quinolinyl)‐malonates 3 cyclize to give 1‐methoxycarbonylisoxazolo[3,4‐c]quinolin‐4(5H)‐ones 5. The necessary reaction conditions can be obtained easily with the help of differential scanning calorimetry.
Thermolysis of 3‐azidophenalen‐1‐ones to naphtho[8,1‐ab]carbazolones and naphtho[8,1‐ab]‐8a‐azonia‐9‐λ2‐azafluoren‐7‐ones
Authors: Fischer Michaela , Stadlbauer Wolfgang 
Published: April 2009

Abstract3‐Azido‐1‐phenalenones 4 with aryl‐ or hetarylsubstituents in position 2 cyclized by thermolysis to give naphtho[8,1‐ab]carbazolones 5 or naphtho[8,1‐ab]‐8a‐azonia‐9‐λ2‐azafluorenones 7. Reduction of the azides 4 gave the corresponding amino derivatives 9. The thermolysis conditions were studied by differential scanning calorimetry.
Singlet and triplet photocycloaddition reactions of 2‐pyridones with propenoate and 2,4‐pentadienotes, and the frontier molecular orbital analysis
Authors: Suishu Takaaki , Tsuru Seiichiro , Shimo Tetsuro , Somekawa Kenichi 
Published: April 2009

AbstractRegioselective photocycloadditions of 2‐pyridones (1) with 2,4‐pentadienoates (3) were analysed and compared with the reactions with propenoate (2), and origins of the different regioselectivities were inferred from frontier molecular orbital properties by the use of PM3‐CI method.Direct photoreactions of 1 with 3 being α,β,γ,δ‐unsaturated carboxylates gave four types of regio‐selective [2+2]cycloadducts, 3‐β:4‐α‐4, 5, 3‐δ:4‐γ‐6,7,5‐δ: 6‐γ‐8, 9 and 5‐δ:6‐γ‐[2+2]cycloadducts 10,11. Sensitized photoreactions of 1 with 3 did not occur, and fluorescence of 1 was weakly quenched by 3. Otherwise, main cycloadducts in the sensitized reactions of 1 with 2 have been obtained as 5‐α:6‐β‐[2+2]cycloadducts, which were different from main 3‐β:4‐α‐[2+2]cycloadducts of the direct reactions, and these site‐and regio‐selectivities were inferred from the different frontier molecular orbital coefficients at the. 3‐and 6‐positions of 1 for the triplet and singlet states. Formations of 4–7 were also interpreted by both effects of frontier orbital HSOMO‐LUMO interactions and of the electrostatic interaction between 1 and 3. The other site‐and regioselective adducts 8–11 were inferred to be formed by the electrostatic interactions similar to 2‐pyridone photodimerization.
Direct introduction of heterocyclic residues into 1,2,4‐triazin‐5(2H)ones
Authors: Rusinov Vladimir L. , Zyryanov Grigori V. , Pilicheva Tatjana L. , Chupakhin Oleg N. , Neunhoeffer Hans 
Published: April 2009

Abstract3‐Aryl‐1,2,4‐triazin‐5(2H)‐ones 1a‐c react with indoles 2a‐c in trifluoroacetic acid/chloroform or in boiling butanol or acetic acid to give 3‐aryl‐6‐(indolyl‐3)‐1,6‐dihydro‐1,2,4‐triazin‐5(2H)‐ones 3a‐g. Oxidation of the dihydro‐1,2,4‐triazin‐5(2H)‐ones 3a‐e afforded 6‐(indolyl‐3)‐1,2,4‐triazin‐5(2H)‐ones 4a‐e, products of nucleophilic substitution of hydrogen in 1a‐c. Refluxing 1b with N‐methylpyrrote 5b in butanol for an extended time resulted in the formation of 3‐(4‐chlorophenyl)‐6‐(1‐meuiylpyrrolyl‐2)‐1,2,4‐triazin‐5(2H)‐one 4h. The reaction of 1a‐c with indoles 2a‐c, pyrroles 5a,b, 1,3‐dimethyl‐2‐phenylpyrazol‐4‐one (8) and aminothiazoles 9a,b in acetic anhydride affords the 1‐acetyl‐3‐aryl‐6‐hetaryl‐1,6‐dihydro‐1,2,4‐triazin‐5(2H)‐ones 6a‐s. Reaction of 1a‐c with N‐methyl‐pyrrole 5b in acetic anhydride gives beside the 1:1 addition products 6h‐k also the 2:1 addition products 7a‐c.
Synthesis, pharmacokinetics, and biological activity of a series of new pyridonecarboxylic acid antibacterial agents bearing a 5‐fluoro‐2‐pyridyl group or a 3‐fluoro‐4‐pyridyl group at N‐1
Authors: Yoon Sung June , Chung Yong Ho , Lee Chi Woo , Oh Yoon Seok , Choi Dong Rack , Kim Nam Doo , Lim Jae Kyung , Jin Yoon Ho , Lee Dug Keun , Lee Won Yong 
Published: April 2009

AbstractThe 1‐(5‐fluoro‐2‐pyridyl) or 1‐(3‐fluoro‐4‐pyridyl) group was introduced in the syntheses of new pyridonecarboxylic acid antibacterial agents. 1‐(5‐Fluoro‐2‐pyridyl)‐6‐fluoro‐1,4‐dihydro‐7‐(4‐methyl‐1‐piperazinyl)‐4‐oxoquinolone‐3‐carboxylic acid 7b (DW‐116) showed a moderatein vitroantibacterial activity but it was found to have very excellent pharmacokinetic profiles so that 7b (DW‐116) showed dramatic increasedin vivoefficacy.
Cyclocondensation reaction of a 1,5‐diketone with 1,2‐diamines
Authors: Márton‐Merész Magda , Zára‐Kaczián Erzsébet , Boros Sándor , Mátyus Péter 
Published: April 2009

AbstractReaction of 2‐acetonyl‐4,5‐dimethoxy‐3′‐chlorobenzophenone (1) with ethylenediamine afforded the imidazo[2,1‐a]isoquinoline 2, whereas 6‐(3‐chlorophenyl)‐8,9‐dimethoxybenzo[b]phenazine (3) and naphthol 4 were obtained with ortho‐phenylenediamine.
Stereoselective Michael addition of 6‐amino‐1,3‐dimethyl‐2,4‐pyrimidinedione to the exocyclic methylene of three sesquiterpene lactones. 1H and 13C NMR evidence of a new C‐C bond and lactam formation
Authors: Dfaz Eduardo , Barrios Hector , Nava Jose Luis , Enriquez Raul G. , Guzmán Angel , Leticia León G. , Fuentes Jose Fernando , Aidee Fuentes B. , Quintero Angelina , Solano Jose Dolores 
Published: April 2009

AbstractThe Stereoselective addition of the pyrimidine derivative 1 to the exocyclic methylene of the α,β unsaturated dehydrocostus lactone 2, Ivalin acetate 3 and Zaluzanin A diacetate 4, was achieved resulting in a new C‐C bond formation. In the cases of compounds 3 and 4, after the addition, the lactone was cleaved followed by reclosure into a lactam ring system.
Functionalization and cyclization reactions of various acetanilides with 4‐benzoyl‐5‐phenyl‐2,3‐furandione. Experimental and theroetical investigations
Authors: Yildirim Ismail , Ilhan I. Özer 
Published: April 2009

Abstract4‐Benzoyl‐5‐phenyl‐2,3‐furandione (1) reacts with acetanilides 3a‐c under different conditions and gives the new open chained dibenzoylacetic acid derivatives 5a‐c, 6 and a new heterocyclic compound such as oxazole derivative 7. The electronic structures of the reactants, transitional states and final products of the reactions are investigated on the basis of AM1 method.
A two‐step synthesis of diaminofurazan and synthesis of N‐monoarylmethyl and N,N′‐diarylmethyl derivatives
Authors: Zelenin Alexander K. , Trudell Mark L. 
Published: April 2009

AbstractDiaminofurazan (1) was synthesized from glyoxal (2) by an improved two‐step procedure. The N‐mono‐arylmethyl derivatives 4a‐e and N‐N'‐diarylmethyl derivatives 5a‐e of 1 were prepared in good yields by reductive alkylation with the corresponding aryl aldehydes.
Synthesis of 1‐halophenyl 4‐(2‐imidazolyl)‐1‐butanones and 5‐(2‐imidazolyl)‐1‐pentanones and their ketalization with glycerol
Authors: Huang Liang‐Fu , Bauer Ludwig 
Published: April 2009

AbstractAn alternate synthesis of 1‐(2,4‐dichlorophenyl)‐4‐(2‐imidazolyl)‐1‐butanones 5d is presented after 1‐[(dimethylamino)methyl‐ and 1‐methyl]‐2‐lithioimidazole failed to be substituted satisfactorily by 2‐(2,4‐dichlorophenyl)‐2‐(3‐iodopropyl)‐1,3‐dioxolane (3b). The Pinner addition of ethanol to 2‐(2,4‐dichlorophenyl)‐2‐(3‐cyanopropyl)‐1,3‐dioxolane yielded the corresponding imidate which was reacted with 1‐amino‐2,2‐dimethoxyethane to form an amidine. Hot dilute hydrochloric acid converted this ami‐dine to the 2‐imidazolyl ketone 5b. Syntheses of homologous 1‐(4‐chloro‐ and 2,4‐dichlorophenyl)‐4‐(2‐imidazolyl)‐1‐pentanones 20 are described. Ketalizations of 5 and 20 with glycerol formed imidazolyl 1,3‐dioxolanyl alcohols. Selective N‐ and O‐alkylations of some of these imidazolyl alcohols are described.
Retro‐ene reactions IV. Alkylation of 4,5‐dichloro‐1‐hydroxy‐methylpyridazin‐6‐one with α,ω‐dibromoalkanes or 4,5‐dichloro‐1 ‐(ω‐bromoalkyl)pyridazin‐6‐ones
Authors: Kim Sung‐Kyu , Cho Su‐Dong , Yoon Yong‐Jin 
Published: April 2009

AbstractAlkylation of 4,5‐dichloro‐1‐hydroxymethylpyridazin‐6‐one (1) with α,ω‐dibromoalkanes 2 or ω‐bromo‐alkylpyridazin‐6‐ones 3 via a fragmentation of the retro‐ene type under the two restricted conditions was investigated.
Mass spectral studies of some 1,2,4‐oxa‐(thia)diazol‐5(4H)‐ones(thiones)
Authors: Dürüst Yasar , Faggi Cristina 
Published: April 2009

AbstractElectron ionization mass spectra of some 3,4‐disubstituted 1,2,4‐oxadiazole‐5(4H)‐thiones, thiadiazol‐5(4H)‐ones and thiadiazole‐5(4H)‐thiones are reported and fragmentation pathways of their molecular ions are studied in view of metastable ion experiments and accurate mass measurements. The main fragmentation route of the compounds under investigation is retro 1,3‐dipolar cycloaddition.
Preparation of 4‐hydroxy‐3‐substituted, 2H‐1‐benzopyran‐2‐ones and 2H‐1‐benzothiopyran‐2‐ones from carboxylic esters and methyl salicylates or methyl thiosalicylate
Authors: Davis Sharon E. , Church A. Cameron , Tummons Rebecca C. , Beam Charles F. 
Published: April 2009

AbstractC(α)‐Carboxylic acid esters were treated with excess lithium diisopropylamide, condensed with methyl salicylates or methyl thiosalicylate, followed by acid cyclization to either 4‐hydroxy‐3‐substituted, 2H‐1‐benzopyran‐2‐ones (coumarins), or 2H‐1‐benzothiopyran‐2‐ones (thiocoumarins).
Synthesis and spectroscopy of phosphonate derivatives of uracil and thymine. X‐ray crystal structure of diethyl 6‐uracilmethylphosphonate
Authors: Ochocki Justyn , Erxleben Andrea , Lippert Bernhard 
Published: April 2009

AbstractA new class of phosphonate ligands, derived from uracil and thymine was designed, prepared and characterised. Dimethyl (4, 7) and diethyl (5, 8) uracilmethylphosphonates have been prepared by the reaction of chloromethyluracil isomers 2 and 3 with trimethyl phosphite and triethyl phosphite, respectively. The corresponding free acids, 5‐uracilmethylphosphonic acid 6 and 6‐uracilmethylphosphonic acid 9, have also been isolated. The structure of the compounds has been assigned by nmr spectroscopy and, in the case of 8, confirmed by X‐ray analysis.
Intermediates for the synthesis of tetracyclic indole alkaloids. Synthesis of 4‐aminotetrahydrocarbazole derivatives
Authors: Patir Süleyman , Okay Görol , Gülce Ahmet , Salih Bekir , Hökelek Tuncer 
Published: April 2009

AbstractAn efficient method for the synthesis of 4‐aminotetrahydrocarbazole derivatives from 2,3‐dihydrospiro‐[1H‐carbazole‐1,2′‐(1,3)‐dithiolan]‐4‐(9H)‐one 1 is described. The structure of compound 6 has been confirmed by X‐ray structure analysis.
A new synthesis of 4‐phosphorylchromenes from 3‐nitrochromenes
Authors: Ono Noboru , Banshou Natsuko , Ito Satoshi , Murashima Takashi , Ogawa Takuji 
Published: April 2009

Abstract3‐Nitrochromenes are readily converted into 4‐phosphorylchromenes on treatment with dialkyl phosphite in the presence of triethylamine in 60–70% yield. This method provides a general method for the preparation of alkenyl phosphonates from nitroalkenes and dialkyl phosphite.
1,2,4‐Triazoles. Improved synthesis of 5‐substituted 4‐amino‐3‐mer‐cato‐(4H)‐1,2,4‐triazoles and a facile route to 3,6‐disubstituted 1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazoles
Authors: Invidiata Francesco Paolo , Furná Giancarlo , Lampronti Ilaria , Simoni Daniele 
Published: April 2009

AbstractThe reaction of thiocarbohydrazide with carboxylic acids at the melting temperature allows an improved preparation of the S‐substituted 4‐amino‐3‐mercapto‐1,2,4‐triazole heterocycles. The crude 4‐amino‐5‐mercapto‐1,2,4‐triazoles react easily with carboxylic acids or carboxylic acid chlorides to afford the 1,2,4‐triazolo[3,4‐fc][1,3,4]thiadiazole ring system.
Synthesis of vinca alkaloids and related compounds LXXXV. Studies with azepino[3,4‐b]indoles
Authors: Dancsó Andràs , Kajtár‐Peredy Mária , Szántay Csaba 
Published: April 2009

AbstractThe synthesis of some new pyrido[1′,2′:1,2]azepino[3,4‐b]indoles starting from indole‐3‐propanamine 1 is described. Stereochemistry and observed side reactions are discussed.
Reaction of N1‐acylacetamidrazones with trifluoroacetylvinyl ethers. Synthesis of new 4‐trifluoromethyl‐ and 6‐trifluoromethylpyridines
Authors: Cocco Maria Teresa , Congiu Cenzo , Onnis Valentina , Bernard Angela Maria , Piras Pier Paolo 
Published: April 2009

AbstractThe reaction between N1‐acylacetamidrazones 1 and enol ether 2 is described. Depending on the reaction conditions and on the substitution pattern of amidrazones 2‐acylhydrazino‐4‐methyl‐6‐trifluoro‐methylpyridines 3 and/or 2‐acylhydrazino‐6‐methyl‐4‐trifluoromethylpyridines 4 were obtained.
Synthesis and reactions of 1‐(2‐oxopropyl)pyridazin‐6‐ones
Authors: Choi Woo‐Yong , Cho Su‐Dong , Kim Sung‐Kyu , Yoon Yong‐Jin 
Published: April 2009

AbstractOxopropylation of 4,5‐dihalopyridazin‐6‐ones with chloroacetone afforded the corresponding 1‐(2‐oxo‐propyl) derivatives. Reaction of title compound with nucleophiles such as amines, alkoxides were investigated. In addition, selective reduction of 3‐nitro‐1‐(2‐oxopropyl)pyridazin‐6‐ones with iron/ammonium chloride in two phase solutions or zinc in acetic acid gave the corresponding 3‐amino or 3‐hydroxyimino derivatives.
New epoxyisoindolines by intramolecular diels‐alder reactions of some methyl‐substituted allylaryl‐2‐furfurylamines
Authors: Mance Ana Dunja , Šindler‐Kulyk Marija , Jakopčić KreŠImir , Hergold‐Brundić Antonija , Nagl Ante 
Published: April 2009

AbstractN‐Alkenyl‐N‐(5‐substituted‐2‐furfuryl)‐N‐p‐toluidines 1–10 have been selected to study the intramolecular Diels‐Alder reaction of furans. New epoxyisoindolines 11–20 were prepared and fully characterised.
Microwave synthesis and anticonvulsant activity of new 3‐benzyl‐1,2,3‐benzotriazin‐4(3H)‐ones
Authors: Komet Milton J. 
Published: April 2009

AbstractSeveral 3‐benzyl‐1,2,3‐benzotriazin‐4(3H)‐ones 1 were prepared by alkylation of 1,2,3‐benzotriazin‐4(3H)‐one with benzyl halides in dimethylformamide in a microwave oven in moderate yields. Accompanying 1 were minor amounts of products believed to be the O‐alkylated derivatives. Support for 3‐benzylation is shown by an alternate synthesis of la from o‐amino‐N‐benzylbenzamide by nitrous acid cyclization. The title compounds were evaluated in mice and rats in maximal electroshock (MES) and pentylenetetrazole (scMet) seizure models for anticonvulsant activity, and in the rotorod test for neurotoxi‐city. They were generally non‐toxic. The 3‐benzyl analog was the most active (maximal electroshock) compound; it's maximal electroshock ED50 value was 93 mg/kg (mouse).
Biomimetic synthesis of 4‐acetylbenzoxazolin‐2(3H)‐one isolated from Zea mays
Authors: Escobar Carlos A. , Kluge Michael , Sicker Dieter 
Published: April 2009

Abstract4‐Acetylbenzoxazolin‐2(3H)‐one has been prepared biomimetically during attempts to synthesize the hemiacetalic hydroxamic acid 5‐acetyl‐2,4‐dihydroxy‐2H‐1,4‐benzoxazin‐3(4H)‐one by the immediate degradation of this unstable compound generated as an intermediate. Thus, 4‐acetylbenzoxazolin‐2(3H)‐one recently isolated from Zea mays kernels, and similar to other benzoxazolin‐2(3H)‐ones known from plant sources, is assumed to have originated from the degradation of natural 5‐acetyl‐2,4‐dihydroxy‐2H‐1,4‐benzoxazin‐3(4H)‐one which in turn could have been enzymatically released by a β‐glucosidase from the corresponding 2‐β‐D‐glucoside.
Pyridazines. 84. Pyridazino[3,4‐e]pyrido[3,2‐b][1,4]diazepine, a novel tricyclic ring system
Authors: Heinisch Gottfried , Matuszczak Barbara 
Published: April 2009

AbstractThe preparation of pyridazino[3,4‐e]pyrido[3,2‐b][1,4]diazepin‐5‐ones 8 and 9 starting from appropriately substituted pyridazine‐4‐carboxamides is reported. The new compounds were tested for HIV‐1 reverse transcriptase inhibitory activity.
Improved synthesis of 2‐substituted 4‐chlorothiazole‐5‐carbaldehydes
Authors: Debski Norbert , Hanefeld Wolfgang , Schlitzer Martin 
Published: April 2009

AbstractAn improved method for the reaction of 2,4‐dichlorothiazole‐5‐carbaldehyde (2) with secondary amines was established using potassium carbonate in acetonitrile at room temperature instead of deprotonation with butyllithium in tetrahydrofuran at −78°. The method is convenient and the yields of 3 even higher. Compound 2 could also be reacted by this method with thiophenols to yield 4‐chloro‐2‐phenylthiothiazole‐5‐carbaldehydes 4.
Asymmetric synthesis of (R)‐6‐amino‐1‐methyl‐4‐(3‐methyl‐benzyl)hexahydro‐1H‐1,4‐diazepine from L‐asparagine
Authors: Kato Shiro , Harada Hiroshi , Mode Toshiya 
Published: April 2009

AbstractAn efficient asymmetric synthesis of (R)‐6‐amino‐1‐methyl‐4‐(3‐rnethylbenzyl)hexahydro‐1H‐1,4‐diazepine [(R)‐2] which serves as the amine part of (R)‐1, a potent and selective 5‐HT3 receptor antagonist, is described. Formation of the hexahydro‐1H‐1,4‐diazepine ring was achieved by the intramolecular ami‐dation of the optically active aminocarboxylic acid 18 or reductive cyclization of the optically active aminoaldehyde 25. Compounds 18 and 25 were prepared from L‐asparagine via the key aziridine derivatives 15 and 22, respectively, with retention of the configuration. The intramolecular aziridine ring opening reaction of 29 gave the C2N bond cleavage product of the aziridine ring, the piperazin‐5‐one 30, as the main product along with the desired 7‐membered ring, the hexahydro‐1H‐1,4‐diazepine product 19.
Intramolecular amidoalkylation cyclizations in synthesis of novel pyrrolo(or isoindolo)thieno[2]benzazepines
Authors: Mamouni Aïcha , Pigeon Pascal , Daïch Adam , Decroix Bernard 
Published: April 2009

AbstractThieno[2]benzazepines annulated to pyrrole 8a,b or isoindole 8c have been synthesized utilizing the acid‐catalyzed cyclization of hydroxylactams 7a‐c as key step.
Alkyl (E,Z)‐2‐(2‐benzoyl‐2‐ethoxycarbonyl‐1‐ethenyl)amino‐3‐dimethylaminopropenoates in the synthesis of fused pyrimidinones. A facile route to 3‐aminoazino‐4H‐pyrimidin‐4‐ones
Authors: Strah Sonja , Golobič Amalija , Golič Ljubo , Stanovnik Branko 
Published: April 2009

AbstractAlkyl (E,Z)‐2‐(2‐benzoyl‐2‐ethoxycarbonyl‐1‐ethenyl)amino‐3‐dimethylaminopropenoates 1a,b react with het‐eroarylamines 2 to give alkyl 2‐(2‐benzoyl‐2‐ethoxycarbonyl‐1‐ethenyl)amino‐3‐heteroarylaminopropenoates 3‐13. These were cyclized into fused 3‐(2‐benzoyl‐2‐ethoxycarbonyl‐1‐ethenyl)amino‐4H‐azolo‐ (or azino)‐pyrim‐idin‐4‐ones 14‐18. 2‐Benzoyl‐2‐ethoxycarbonyl‐1‐ethenyl group can be easily removed from 3‐(2‐benzoyl‐2‐ethoxycarbonyl‐1‐emenyl)amino‐8‐memyl‐4H‐pyrido[1,2‐a]pyrimidin‐4‐one (14) to give 3‐amino‐8‐methyl‐4H‐pyrido[1,2‐a]pyrimidin‐4‐one (19). The structure of 1a was confirmed by X‐ray analysis.
On triazoles. XXXIX. Synthesis and structure of some 1,2,4‐triazolo[1,5‐a]pyrimidin‐5‐one oximes
Authors: Reiter József , Reiter József 
Published: April 2009

AbstractSome 1,2,4‐triazolo[1,5‐a]pyrimidin‐5‐one derivatives 1 and their alicyclic condensed ring analogues 2‐3 were converted through the corresponding “imino chlorides” 4‐6 to the oximes 7‐9. The “E” isomeric structure of the products obtained was proven with the use of cmr using the spectral data of the corresponding “benzyloximino” derivatives 10‐12 prepared as model compounds.
Enzymatic resolution of flavanone oximes
Authors: Izumi Taeko , Suenaga Kouji 
Published: April 2009

AbstractThe optically active (R)‐ and (S)‐flavanones were prepared by an enzymatically enantioselective hydrolysis of (±)‐flavanone oxime O‐acylates employing lipases, followed by hydrolysis with acid.
A selective synthesis of 2‐arylamino‐4H‐1,3,4‐thiadiazino[5,6‐b]‐quinoxalines and mesoionic triazolo[4,3‐a]quinoxaline
Authors: Kim Ho Sik , Kim Tong Eun , Kwag Sam Tag , Park Yong Tae , Hong Young Seuk , Okamoto Yoshihisa , Kurasawa Yoshihisa 
Published: April 2009

AbstractThe reaction of the 6‐chloro‐2‐(1‐methyl‐2‐thiocarbamoylhydrazino)quinoxaline 4‐oxides 3a‐d with trifluoroacetic anhydride gave the 2‐(N‐aryl)trifluoroacetamido‐8‐chloro‐4‐methyl‐4H‐1,3,4‐thiadiazino‐[5,6‐b]quinoxalines 7a‐d, respectively, while the reflux of compounds 3a‐c in N,N‐dimethylformamide afforded the mesoionic triazolo[4,3‐a]quinoxaline 4. Hydrolysis of compounds 7a‐d with triethylamine/water provided the 2‐arylamino‐8‐chloro‐4‐methyl‐4H‐1,3,4‐thiadiazino[5,6‐b)]quinoxalines 8a‐d, respectively.
Thiophene 1‐oxides. V. Comparison of the crystal structures and thiophene ring aromaticity of 2,5‐diphenylthiophene, its sulfoxide and sulfone
Authors: Pouzet Pascale , Erdelmeier Irene , Ginderow Daria , Dansette Patrick M. , Mansuy Daniel , Mornon Jean‐Paul 
Published: April 2009

AbstractThe detailed preparation of 2,5‐diphenylthiophene 1‐oxide (2) is reported as well as the comparative study of the crystal structures of 2,5‐diphenylthiophene, 1, its sulfoxide 2 and sulfone 3 obtained by X‐ray diffraction. This work represents the first experimental study of a complete heterocyclic series, including a thiophene derivative, and the corresponding sulfoxide and sulfone. On the basis of the geometrical parameters, the first unequivocal experimental parameters obtained for a thiophene 1‐oxide derivative, we have also examined the evolution of the aromatic character of the thiophene ring when oxidizing the sulfur atom to the sulfoxide and the sulfone. Paolini's bond orders and Julg and Francois's aromaticity indices have also been calculated for the three compounds and compared to those previously calculated for related thiophene derivatives by semi‐empirical or ab initio methods [6], [7]. All the data examined showed that, in spite of its non planarity, the thiophene ring of 2,5‐diphenylthiophene 1‐oxide 2 could still exhibit some de localization of its p electrons indicating a certain degree of aromaticity lower than in thiophene 1 but higher than in the sulfone 3.