bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of the friedel‐crafts acylation of 1‐benzenesulfonyl‐1H‐pyrrole in the preparation of 3‐aroylpyrroles
Authors: Nicolaou Ioannis , Demopoulos Vassilis J.
Published: March 2009

In this work, we studied the aluminum chloride catalyzed reaction of 1‐benzenesulfonyl‐1H‐pyrrole with a series of eleven aroyl chlorides. The products formed were not isolated, but hydrolyzed to the target 3‐aroylpyrroles in overall yields, usually, higher than 50%. However, in the cases with the π electron rich 1‐phenyl‐1H‐pyrrole‐3‐carbonyl chloride and 1‐methyl‐1H‐indole‐3‐carbonyl chloride significant C‐2 substitution occured, resulting in the isolation of the corresponding 1‐benzenesulfonyl‐2‐aroylpyrroles as the predominant or the sole products. The desired C‐3 isomers were synthesized starting with 1‐triisopropylsilanyl‐1H‐pyrrole.
Reductive metallation of 6‐methyl‐2,3‐diphenylquinoxaline. Synthesis of 1,4‐dihydro‐1,4‐diazine derivatives
Authors: Öcal Nüket , Turgut Zuhal , Kaban Şniz
Published: March 2009

The reductive metallation of 6‐methyl‐2,3‐diphenylquinoxaline 1 with sodium metal in tetrahydrofuran and inert atmosphere to a monomeric dianion 2 has been explored and the nucleophilicity of this disodium adduct was investigated with various alkylation and acylation reagents. An annulation of the pyrazine ring system was accomplished by treating the dianion with polymethylene chlorides, Cl(CH2)nCl, n = 3,4.
The preparation of 4‐oxo‐N‐aryl‐4H‐1‐benzopyran‐2‐acetamides by the condensation/cyclization of trilithiated acetoacetanilides with lithiated methyl salicylates
Authors: Hurst Douglas R. , French Kristen L. , Angel April J. , Williams Angela R. , Rampey Mary E. , Guion Tina S. , Chan Kam W. , Kassis Camille M. , Martinez Shannon L. Studer , Beam Charles F.
Published: March 2009

Several acetoacetanilides were trilithiated in excess lithium diisopropylamide, and the resulting polylithiated intermediates were regioselectively condensed with lithiated methyl salicylates followed by acid cyclization to substituted 4‐oxo‐N‐aryl‐4H‐1‐benzopyran‐2‐acetamides (benzopyranone‐2‐acetamides).
Synthesis of indolizidinediones annelated to a furan ring
Authors: Szemes Fridrich , Marchalín ŠTefan , Bar Nathalie , Decroix Bernard
Published: March 2009

The furo[2,3(or 3,2)‐f]indolizidinediones 4a,b were synthesized in five steps from glutamic acid in good yield. The ketones were converted into trans alcohols 5a,b or oximes 6a,b (either as syn‐anti mixture or as single isomer). The selectivity of these reactions is discussed.
A convenient synthesis of (z)‐3‐(α‐alkoxycarbonyl‐α‐cyanomethylene)‐2‐oxo‐1,2,3,4‐tetrahydroquinoxalines and related compounds
Authors: Yamada Yoichi , Yasuda Heinosuke
Published: March 2009

(Z)‐3‐(α‐Alkoxycarbonyl‐α‐cyanomethylene)‐2‐oxo‐1,2,3,4‐tetrahydroquinoxalines 3 and (Z)‐3‐(α‐alkoxycarbonyl‐α‐cyanomethylene)‐3,4‐dihydrobenzo[g]quinoxalin‐2(1H)‐ones 5 possessing various alkoxycarbonyl groups were prepared in good yields directly from the reaction of dialkyl (E)‐2,3‐dicyanobutendioates 1 with o‐phenylenediamine (2) or with 2,3‐diaminonaphthalene (4), respectively. Furthermore, 2,3‐diaminopyridine (6) and 3,4‐diaminopyridine (7) were reacted with the diethyl ester 1b to give (Z)‐2‐(α‐cyano‐α‐ethoxycarbonylmethylene)‐1,2‐dihydro‐4H‐pyrido[2,3‐b]pyrazin‐3‐one (8) and (Z)‐3‐(α‐cyano‐α‐ethoxycarbonylmethylene)‐3,4‐dihydro‐1H‐pyrido[3,4‐b]pyrazin‐2‐one (9), respectively. The structural studies of 3, 5, 8, and 9 were carried out by nmr experiments in some details.
Unusual behavior of pyrazolo[1,2‐a]pyrazoles in fast atom bombardment (fab) and frit‐fast atom bombardment (Frit‐FAB) mass spectrometry. Influence of the matrix
Authors: Enjalbal Christine , Aubagnac Jean‐Louis , Trofimenko Swiatoslaw , Claramunt Rosa , Sanz Dionisia , Elguero José
Published: March 2009

The nature of the matrix used in Fast Atom Bombardment (FAB) mass spectrometry analyses of pyrazolo[1,2‐a]pyrazoles was found to influence significantly their positive and negative ions mass spectra. Indeed the use of glycerol provided an abundant ion corresponding to the protonated molecule (M+H)+ whereas the meta‐nitrobenzyl alcohol favored the formation of the radical ion M+°. Such results which are in accordance with the oxidoreduction properties of the matrices studied were also established in Frit‐FAB mass spectrometry analyses of pyrazolo[1,2‐a]pyrazoles.
Synthesis and reduction of thieno[2′,3′(3′,2′ or 3′,4′):5,6]‐azocino[2,1‐a]isoindole‐7, 13‐diones
Authors: Othman Mohamed , Pigeon Pascal , Decroix Bernard
Published: March 2009

A synthesis of the thieno[2′,3′(3′,2′ or 3′,4′):5,6]azocino[2,1‐a]isoindole‐7,13‐diones 6a‐c was developed from N‐thienylethylphthalimides 3a‐c using a Wittig reaction followed by a Friedel‐Crafts cyclization of acetic acid derivatives 5a‐c. Reduction of ketones 6a‐c into alcohols 7a‐c was stereo specific.
The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 20. Benzo[h]thieno[3′,2′:4,5]thieno[2,3‐c]‐quinoline, benzo[f]thieno[3′,2′:4,5]thieno[2,3‐c]quinoline, benzo[f]thieno[3′,2′:4,5]thieno[2,3‐c]tetrazolo[1,5‐a]quinoline and benzo[f]thieno[3′,2′:4,5]thieno[2,3‐c][1,2,4]triazolo[4,3‐a]quinoline
Authors: Luo Jiann‐Kuan , Federspiel Ronald F. , Castle Raymond N.
Published: March 2009

Four previously unknown polycyclic heterocyclic ring systems, namely, benzo[h]thieno[3′,2′:4,5]‐thieno[2,3‐c]quinoline (6), benzo[h]thieno[3′,2′:4,5]thieno[2,3‐c]quinoline (11), benzo[f]thieno‐[3′,2′:4,5]thieno[2,3‐c]tetrazolo[1,5‐a]quinoline (12) and benzo[f]thieno[3′,2′:4,5]thieno[2,3‐c][1,2,4]‐triazolo[4,3‐a]quinoline (13), were synthesized via oxidative photocyclization. Unequivocal total assignments of the proton and carbon nmr spectra of 6 and 11 were made through the concerted usage of COSY, HMQC and HMBC two‐dimensional nmr spectroscopic methods.
Total synthesis of 5‐demethylellipticine
Authors: Ergün Yavuz , Patir Süleyman , Okay Gürol
Published: March 2009

Ethyl 1,2‐dihydro‐4‐methylcarbazole‐3‐carboxylate and 11‐methl‐6H‐pyrido[4,3‐b] carbazole (5‐demethylellipticine) have been synthesized by different routes.
α,ω‐Bis(4‐substituted‐3‐quinolinylthio)alkanes from reactions of thioquinanthrene with alkoxides
Authors: Boryczka Stanislaw
Published: March 2009

The reaction of thioquinanthrene 1 with sodium alkoxides and α,ω‐dihaloalkanes leads to the formation of α,ω‐bis[4‐(4‐methoxy‐3‐quinolinylthio)‐3‐quinolinylthio]alkanes 4. The yield depends on the nature of α,ω‐dihalo‐alkanes. The effect of α,ω‐dihaloalkanes of the following types: XCH2X (X = Cl,Br,I), X(CH2)2X (X = Cl,Br,I), Br(CH2)3Br and Br(CH2)6Br were studied. The preparation of 4‐alkoxy‐3′‐(ω‐bromoalkylthio)‐3,4′‐diquinolinyl sulfide 3 and their transformation to α,ω‐bis(4‐alkoxy‐3‐quinolinylthio)alkanes 6 were studied as well.
Synthesis of novel pyrindine derivatives from a facile reaction of 2,5‐bisarylidenecyclopentanone and malononitrile
Authors: Al‐Arab Mohammad M. , Al‐Saleh Fowzia S. , Mayoof Sadeq M.
Published: March 2009

Starting from 2,5‐bisarylidenecyclopentanone and malononitrile (1:1) several novel pyrindine derivatives were synthesized by a facile and convenient one‐pot reaction using sodium ethoxide in absolute ethanol at room temperature. The structure of the reaction products was unambiguously deduced ftom their infrared, 1H‐nuclear magnetic resonance spectroscopy, elemental analysis and single crystal X‐ray crystallography.
Urea as leaving group in the synthesis of 3‐(tert‐butyl)perhydro‐1,5,3‐dithiazepine
Authors: Wellmar Ulf
Published: March 2009

The new compound 3‐(tert‐butyl)perhydro‐1,5,3‐dithiazepine has been synthesised from 5‐(tert‐butyl)perhydro‐1,3,5‐triazin‐2‐one in 45% yield. In the reaction, urea acts as the leaving group being exchanged for the S‐CH2‐CH2‐S fragment of the product.
Selenium heterocycles. XLIII. Syntheses of 3,5‐Diaryl‐1,2,4‐thiadiazoles and 3,5‐Diaryl‐1,2,4‐selenadiazoles
Authors: Shafiee A. , Ebrahimzadeh M. A. , Maleki A.
Published: March 2009

Starting from readily available α‐arylsulfonyl‐α‐bromoacetophenones 2 a series of 3,5‐diaryl‐1,2,4‐thiadiazoles and 3,5‐diaryl‐1,2,4‐selenadiazoles were prepared in moderate yield. Reaction of compounds 2 with thiourea or selenourea gave 2‐amino‐5‐arylsulfonyl‐4‐phenylthiazole or selenazole in good yield.
Synthesis of 2′‐[2‐(5‐benzyloxyindolyl)]propylamine derivatives
Authors: Marco José L. , Martin Gema
Published: March 2009

The synthesis of some 2′‐[2‐(5‐benzyloxyindolyl)]propylamine derivatives 1–15 from 2‐(5‐benzyloxyindole)carboxyaldehyde (16) and 2‐(5‐benzyloxy‐1‐methylindole) carboxyaldehyde (17) is reported. Compounds 1–15 have been designed as potential monoamine oxidase A and B inhibitors.
On the reaction of 3‐nitro‐1,2‐phenylenediamine with ethyl acetoacetate. Condensed dihydrodiazepinones
Authors: Puodžiūnaitė Benedikta , Kosychova Lidija , Stumbrevičiūtė Zita , Jančienė Regina , Talaikytė Zita
Published: March 2009

Condensation of 3‐nitro‐1,2‐phenylenediamine with ethyl acetoacetate in boiling xylene gave two isomeric 2,3‐dihydro‐4‐methyl‐9‐nitro‐ and 2,5‐dihydro‐4‐methyl‐6‐nitro‐1H‐1,5‐benzodiazepin‐2‐ones, the 9‐nitro derivative thermal rearrangement product N‐isopropenyl‐4‐nitrobenzimidazolone and a non cyclic acetoacetamide derivative. At room temperature these reactants afforded 2,3‐dihydro‐2‐ethoxycarbonyl‐methyl‐2‐methyl‐4‐nitrobenzimidazole.
6,16‐methano‐6H,16H‐[2,4]benzothiazepino[3,4‐d][1,3,5]benzoxadiazocine and 6,26:13,19‐dimethano‐6H,9H,13H,19H,22H,26H‐benzo[1″,2″:5,6;4″,5″:5′,6′]bis[1,3]thiazepino[2,3‐d:2′,3′‐d]bis[1,3,5]‐benzoxadiazocine: New heterocyclic systems
Authors: Světlík Jan , Liptaj Tibor
Published: March 2009

Cyclization reactions of oxygen‐bridged pyrimidinethione 1a with 1,2‐bis(bromomethyl)benzene and 1,2,4,5‐tetrakis(bromomethyl)benzene leading to conformationally restricted benzothiazepine derivatives were examined. Molecular conformations of the products were studied by 1D and 2D nmr spectroscopy and with the help of semiempirical calculations.
Separation, structural determination and biological evaluation of the thymidylate synthase inhibitor 3,3‐Di‐(4′‐hydroxyphenyl)‐6(7)‐chloro‐1‐oxo‐1H,3H‐naphtho[1,8‐cd]pyran
Authors: Costi M. Paola , Tondi Donatella , Pecorari Piergiorgio , Rinaldi Marcella , Celentano Giuseppe , Ghelli Stefano , Antolini Luciano , Barlocco Daniela
Published: March 2009

The chloro substituted 3,3‐di‐(4′‐hydroxyphenyl)‐1‐oxo‐1H,3H‐naphtho[1,8‐cd]pyran was synthesized in a 40/60 mixture of C6 or C7 substituted isomers, respectively. The two isomers were separated by hplc. The X‐ray crystal structure of the mixture was obtained. Both the mixture and the single isomers were tested against Lactobacillus Casei thymidylate synthase. The X‐ray analysis clearly revealed co‐crystallization of the two isomeric species. The apparent Ki of the mixture was 0.8 muM, while those of the C6 and C7 substituted isomers were 0.42 and 0.52 muM, respectively, thus showing that the position of the chlorine in the naphthalene ring was not critical for enzymatic activity.
On the reaction of meldrum's acid with N‐trimethylsilylanilines substituted by electron withdrawing groups
Authors: Roche Sandrine , Yous Saïd , Couturier Daniel , Rigo Benoît
Published: March 2009

The reaction of Meldrum's acid with silylated anilines substituted by an electron withdrawing group easily yields the corresponding N‐phenyl malonamic acid, when the reaction is performed under high vacuum in dichlorobenzene.
Molecular structure and electronic spectrum of taspine: Semiempirical calculations
Authors: Sato Tsuguo , Kataoka Masahiro
Published: March 2009

AM1 calculations show that taspine has the three energy‐minima along the rotation‐like nuclear displacement of the dimethylaminoethyl group. They correspond to two enantiomeric structures and a Cs structure, which have nearly equal energies. The energy barrier between the enantiomeric structures and the Cs structure is calculated to be about 1 kcal/mol. The small barrier readily causes an intramolecular interconversion of the two enantiomers through the Cs structure and thus results in the optical inactivity of taspine. CNDO/S calculations show that the electronic spectra of the enantiomer and the Cs structure are quite similar. These calculated spectra are in good agreement with the observed electronic spectra.
Solvent‐free synthesis of heterocyclic compounds using microwaves
Authors: Varma Rajender S.
Published: March 2009

Microwave‐enhanced solvent‐free synthetic approach is described that features simplicity, manipulative ease of the operation and conservation of solvents as the main advantages. This eco‐friendly approach, which has found application in facile organic functional group transformations, is applied to rapid assembly of heterocyclic compounds. A variety of solid state reactions are described that occur rapidly at ambient pressure under solventless conditions and provide ready access to intermediates such as enamines and α‐tosyloxyketones which can be transformed in situ to biologically significant heterocyclic compounds such as isoflav‐3‐enes, flavones, quinolones, 2‐aroylbenzo[b]furans and thiazoles in one‐pot operation. Multicomponent reactions under these solvent‐free conditions can be adapted for high speed parallel synthesis and are exemplified by assembly of dihydropyrimidine‐2(1H)‐ones (Biginelli reaction) and imidazo[1,2‐a]annulated pyridines, pyrazines and pyrimidines (Ugi reaction) which may have potential in building a library of such compounds.
Spectroscopic analysis of imidazolidines. Part I: Electron impact mass spectrometry
Authors: Salerno Alejandra , Hedrera Monica E. , Perillo Isabel A. , D'Accorso Norma B. , Alho Miriam Martins
Published: March 2009

The electron impact mass spectral fragmentation pathways for a series of 1,3‐di‐ and 1,2,3‐trisubstituted imidazolidines were investigated. The data show remarkable differences depending on the location and identity of substituents. The atypical 1,2,2,3‐tetrasubstituted imidazolidine, 2‐cyano‐1‐methyl‐3‐(p‐nitro‐phenyl)‐2‐phenylimidazolidine, was also investigated.
Preparation of 1‐substituted‐5‐[(2‐oxo‐2‐phenyl)ethyl]imidazoles
Authors: Aulaskari Paula , Ahlgrén Markku , Vainiotalo Pirjo , Pohjala Esko
Published: March 2009

New high yield preparation methods were developed for the pharmaceutically interesting compounds, 1‐benzyl‐, 1‐methyl‐, and 1H‐5‐[(2‐oxo‐2‐phenyl)ethyl]imidazoles 1a‐c, respectively. The title compounds were synthesized by four different methods using various starting materials. Two of the methods involved transformation reactions of the key intermediates, 1‐substituted‐5‐[(2‐nitro‐2‐phenyl)ethenyl]imidazoles 2a‐c and 1‐substituted‐5‐[(2‐nitro‐2‐phenyl)ethyl]imidazoles 3a‐c, while the other two utilized the oxidation of 1‐substituted‐5‐[(2‐hydroxy‐2‐phenyl)ethyl]imidazoles 4a‐c, with chromic oxide, and the umpolung reaction of benzaldehyde followed by a condensation reaction of the umpolung intermediate with imidazolecarboxaldehydes 6a‐c.
A new synthesis of N‐phenyl lactams
Authors: Markgraf J. Hodge , Stickney Carolyn A.
Published: March 2009

The synthesis of N‐phenyl lactams by phase transfer oxidation of N,N‐(polymethylene) anilines with potassium permanganate is reported.
Formation of a σ‐complex from dicyanopyridinyl and hydroxyalkyl radicals. An ESR study of the photoinitiated complex forming reactions of aryl ketones with 2,4‐pyridinedicarbonitrile and alcohols
Authors: Vittimberga Bruno M. , Rieger Anne L.
Published: March 2009

When a 1° or 2° alcohol solution of benzophenone and 2,4‐pyridinedicarbonitrile (1) is irradiated, the 2,4‐dicyanopyridinyl radical (2) is formed immediately. When the irradiation is performed in the cavity of an ESR spectrometer, the spectrum amplitude increases to a near steady‐state level, α. When the illumination is discontinued, a sharp rise in amplitude is observed to the β level. These results can be interpreted in terms of an equilibrium between free 2 and an ESR‐silent complex of 2 (concentrations proportional to α and β ‐ α, respectively) with Keq = (β ‐ α)/α. The unprecedented increase in signal amplitude when irradiation is stopped requires an alcohol; the effect is not observed when other solvents are used. Keq was found to correlate with the steric bulk of the alcohol solvent. These and other results lead to the conclusion that hydroxyalkyl radicals react reversibly with 2 to form the ESR‐silent complex.
Effect of mixtures of water and organic solvents on the acidities of 5‐membered heteroaromatic carboxylic acids
Authors: Lee Chang Kiu , Jeoung Eun Hee , Lee In‐Sook Han
Published: March 2009

pKa values of various 5‐membered heterocyclic aromatic carboxylic acids (pKas) were determined in solutions of 20.3, 35.2, 50.1, 65.1, and 79.9 weight percent of organic solvents in water. The pKas values show good linearity when they are ploted as a function of the dielectric constants of the mixed solvents methanol, ethanol, isopropyl alcohol, and tert‐butyl alcohol. On the other hand, the pKas values show a poor correlation with the dielectric constants in aqueous acetonitrile, N,N‐dimethylformamide, dimethyl sulfoxide, and dioxane. The pKa values in pure water and in pure organic solvent could be calculated by extrapolation of the plot of the pKas versus percentage of organic solvent. The pKas values of 4‐ and 5‐sub‐stituted 2‐thiophenecarboxylic acids were also determined, and the ρ values are calculated in the same series of the solvents.
An interesting synthesis of thieno[2,3‐d][1,2,3]thiadiazole via decomposition/recyclization of 3‐methoxycarbonyl‐1H‐thieno‐[2,3‐e][1,3,4]thiadiazine 4,4‐dioxide
Authors: Stephens Chad E. , Sowell J. Walter
Published: March 2009

Attempted hydrolysis of the ester of 3‐methoxycarbonyl‐1H‐thieno[2,3‐e][1,3,4]thiadiazine 4,4‐dioxide (I) under acidic conditions gave the ring‐contracted thieno[2,3‐d][1,2,3]thiadiazole (V) instead of the expected carboxylic acid. In addition to a discussion of the reaction, a plausible mechanism is presented.
1,2‐Methyl shift in the reaction of 4,7‐dihydro‐4,5‐dimethyl‐7‐phenyl‐(1,2,4)‐triazolo[1,5‐a]pyrimidine with tosyl azide
Authors: Komykhov Sergey A. , Desenko Sergey M. , Kaganovsky Alexander S. , Orlov Valery D. , Meier Herbert
Published: March 2009

The reaction of the heterocyclic enamine 1 with tosyl azide (2) leads to the tosylimino derivative 4 of 1,2,4‐triazolo[1,5‐a]pyrimidine. The extrusion of nitrogen from the primary adduct 3 is followed by a 1,2‐shift of a methyl group. The structure determination of 4 is based on 1H and 13C nmr spectra including NOE measurements.
Synthesis of 2‐aminoquinazolinc‐4(3H)‐one derivatives as potential potassium channel openers
Authors: Erb BÉNÉDicte , Akue Rufine , Rigo Benoît , Pirotte Bernard , Couturier Daniel
Published: March 2009

Starting from 2‐thioxoquinazolin‐4‐one, the synthesis of 2‐amino‐4(3H)‐one derivatives, structurally related to potassium channels openers pinacidil and diazoxide, is described.
The crystal structure of 9‐chloro‐4,5‐dihydro‐2‐ethyl‐1‐(2,4,6‐trichlorophenyl)‐1H‐1,2,4‐triazolo[3,2‐d][1,5]‐benzoxazepinium hexachloroantimonate
Authors: Liu Xianjun , Liu Yi , Ding Zongbiao , Wang Quanrui , Zhang Chengzhi
Published: March 2009

The title compound 4, i.e. 9‐chloro‐4,5‐dihydro‐2‐ethyl‐1‐(2,4,6‐trichlorophenyl)‐1H‐1,2,4‐triazolo[3,2‐d]‐[1,5]benzoxazepinium hexachloroantimonate, is a novel 6‐7‐5 tricyclic heterocycle. C18H14Cl4N3O·SbCJ6, M = 764.61, P21/c(#14), a = 13.457(4), b = 11.583(2), c = 18.992(3) Å α = 90, β = 110.11(1)°, Z = 4, V = 2780(1) Å3, Dc = 1.827 g/cc, μ (MoKα) = 19.69 cm−1, F(000) = 1488.00, T = 293 K, Rint = 0.055 for 3094 independent reflections with I>3.00σ(I). The five‐membered heterocyclic ring is nearly planar, with the trichlorophenyl ring at N(2) almost perpendicular to it. However, the seven‐membered ring is not planar, but adopts a twist‐boat conformation.
Polar aspects of intramolecular interactions in 2‐amino‐5‐nitro‐4‐methylpyridines and 2‐amino‐3‐nitro‐4‐methylpyridines
Authors: Wandas M. , Puszko A. , Pawelka Z.
Published: March 2009

The dipole moments of twelve 2‐N‐substituted amino‐5‐nitro‐4‐methylpyridines (I‐XII) and three 2‐N‐substituted amino‐3‐nitro‐4‐methylpyridines (XIII‐XV) were determined in benzene. The polar aspects of intramolecular charge‐transfer and intramolecular hydrogen bonding were discussed. The interaction dipole moments, μint, were calculated for 2‐N‐alkyl(or aryl)amino‐5‐nitro‐4‐methylpyridines. Increased alkylation of amino nitrogen brought about an intensified push‐pull interaction between the amino and nitro groups. The solvent effects on the dipole moments of 2‐N‐methylamino‐5‐nitro‐4‐methyl‐(I), 2‐N,N‐dimethylamino‐5‐nitro‐4‐methyl‐ (II) and 2‐N‐methylamino‐3‐nitro‐4‐methylpyridines (XIII) were different. Specific hydrogen bond solute‐solvent interactions increased the charge‐transfer effect in I, but it did not disrupt the intramolecular hydrogen bond in XIII.
Unusual behaviour of N‐cinnamoyl‐2‐hydroxy‐2‐(trifluoromethyl)‐arylethylamines in pictet‐gams cyclization. Synthesis of 2‐styryl‐5‐aryl‐5‐trifluoromethyl‐2‐oxazolines
Authors: Poszávácz LÁSzlÓ , Simig Gyula
Published: March 2009

Cyclization of N‐acyl‐2‐hydroxy‐2‐(trifluoromethyl)arylethylamines 4 under Pictet‐Gams conditions afforded 2‐oxazolines 5 instead of the expected isoquinolines 6. The effect of the trifluoromethyl group on the result of the reaction is discussed.
Studies on the chemistry of thienoannelated O,N‐ and S,N‐containing heterocycles. 17. Preparation of 1H‐thieno[2,3‐b][1,4]thiazine‐1‐carboxarnides as smooth muscle relaxants
Authors: Schreder Maria E. , Erker Thomas
Published: March 2009

A new series of substituted thieno[1,4]thiazines with an urea moiety has been designed. The synthesis and results of replacement of the quinoline and indoline moieties of lead structure 1 are described. The key step in preparation was the substitution with 4‐nitrophenyl chloroformate to obtain the required reactivity for substitution with diamines. Structural modifications of the amino side chain with the aim of finding tissue specific compounds were carried out. Pharmacological testings explored the presumed calcium‐channel‐antagonistic and potassium‐channel‐opening activities.
Synthesis of new thieno and pyrazolo[2,1]benzothiazepine derivatives with potential antidepressant properties
Authors: Vega S. , Díaz J. A. , Darias V. , Mateo C. C. SÁNchez
Published: March 2009

In this paper we describe a series of new thieno and pyrazolo[2,1]benzothiazepine derivatives 7a‐o which were synthesized by two different methods both starting from the previously described tricyclic alcohols 1–3. Several components of this series were effective p. o. (per os, orally) in different pharmacological tests currently employed in the evaluation of antidepressant activity.
Reaction of 4,5,6‐triaminopyrimidine and 2,4,5,6‐tetraaminopyrimidine with 3‐dimethylaminopropiophenones. Synthesis of new 4‐aryl‐2,3‐dihydropyrimido[4,5‐b][1,4]diazepines
Authors: Braulio Insuasty O. , Henry Insuasty I. , Jairo Quiroga P. , Saitz Claudio , Jullian Carolina
Published: March 2009

Several new 6‐amino‐ and 6,8‐diamino‐4‐aryl‐2,3‐dihydropyrimido[4,5‐b][1,4]diazepines were obtained from the reaction of 4,5,6‐triaminopyrimidine 1a and 2,4,5,6‐tetraaminopyrimidine 1b with one equivalent of 3‐dimethylaminopropiophenones 2 in absolute ethanol. Structure analysis of 6‐amino‐ and 6,8‐diamino‐4‐aryl‐2,3‐dihydropyrimido[4,5‐b][1,4]diazepines 3a‐i, determined by detailed nmr measurements, reveals a high regioselectivity of this reaction.
Chiral nitrone reagents for cycloaddition reactions
Authors: Jones Raymond C. F. , Martin Jason N. , Smith Paul
Published: March 2009

The preparation and cycloaddition reactions of new imidazoline nitrones are described. The imidazo[1,2‐b]isoxazole alkene cycloadducts are formed via an exo approach. An example has been tranformed into a pyrrolo[1,2‐a]imidazole as a prelude to a new pyrrolidine synthesis.
Enantioselective total synthesis of marine alkaloids, manzamine A and related compounds
Authors: Nakagawa Masako
Published: March 2009

A review of our studies toward the enantioselective total synthesis of ircinal A, manzamine A and related compounds is presented in detail.
Reactions of 1‐(3‐aryl‐3‐oxopropenyl)azulenes and 1‐cinnamoylazulenes with malononitrile: Synthesis of 1‐(2‐aryl‐4‐pyridyl)azulenes and 1‐(4‐aryl‐2‐pyridyl)azulenes
Authors: Wang Dao‐Lin , Imafuku Kimiaki
Published: March 2009

The reactions of 1‐formyl‐3‐methoxycarbonylazulene (1) with acetophenones 3a‐e gave 1‐(3‐aryl‐3‐oxopropenyl)‐3‐methoxycarbonylazulenes 4a‐e which reacted with malononitrile in the presence of sodium methoxide to afford 1‐(2‐aryl‐4‐pyridyl)‐3‐methoxycarbonylazulenes 9a‐d, except for 4′‐nitro‐substituted compounds. Heating of the compounds 9a‐d in 100% phosphoric acid yielded 1‐(2‐aryl‐4‐pyridyl)azulenes 10a‐d. In a similar manner, 1‐(4‐aryl‐2‐pyridyl)azulenes 12a‐1 and 1‐[4‐(2‐furyl)‐ and 4‐(2‐thienyl)‐2‐pyridyl)]azulenes 14a,b were obtained.
Chlorination of 3,4,5‐trichloropyridazin‐6‐one and synthesis of 3,4,5‐trichloro‐1‐(4,5,6‐trichloropyridazin‐3‐yl)pyridazin‐6‐one
Authors: Kang Young‐Jin , Lee Woo Song , Kim Ho‐Kyun , Yoon Yong‐Jin , Shiro Motoo
Published: March 2009

This paper presents the chlorination of 3,4,5‐trichloropyridazin‐6‐one and the synthesis of 3,4,5‐trichloro‐1‐(4,5,6‐trichloropyridazin‐3‐yl)pyridazin‐6‐one.
Synthesis of substituted tetrahydroisoquinolines and benzo[d]azepines from phthalan or isochroman and N‐silylaldimines
Authors: Foubelo F. , Gómez C. , Gutiérrez A. , Yus M.
Published: March 2009

The 4,4′‐di‐tert‐butylbiphenyl‐catalyzed lithiation of phthalan (1a) and isochroman (1b) in THF at 0°C affords the corresponding functionalized benzyllithiums 2, which by reaction with N‐silylaldimines yield, after acid‐base work‐up, the expected amino alcohols 3. Successive treatment of these amino alcohols with thionyl chloride and sodium hydroxide yields the corresponding substituted benzofused six‐ and seven‐membered nitrogen‐containing heterocycles 4.
Synthesis and properties of new types of sulfoxide‐ or sulfone‐bridged lewis acids
Authors: Ohba Yoshihiro , Ito Kazuaki , Nagasawa Tomomi , Sakurai Shinya
Published: March 2009

A series of new types of sulfur‐bridged Lewis acids were synthesized. The ligands that contained the sulfoxide or sulfone as the joint moieties of two phenols were found to quantitatively give Lewis acids. These obtained Lewis acids also have good discrimination properties of some epoxides. The reaction prop erties of the Lewis acids were studied using the rearrangement of the epoxides to carbonyl compounds.
Synthesis of novel 3‐ and 5‐substituted indole‐2‐carboxamides
Authors: Bratton Larry D. , Roth Bruce D. , Trivedi Bharat K. , Unangst Paul C.
Published: March 2009

The preparation of several novel 3,5‐substituted‐indole‐2‐carboxamides is described. A 5‐nitro‐indole‐2‐carboxylate was elaborated to the 3‐benzhydryl ester, N‐substituted ester, and carboxylic acid intermedi ates, followed by conversion to the amide and then reduction of the 5‐nitro group to the amine. Indole‐2‐carboxamides with 3‐benzyl and 3‐phenyl substituents were prepared in four steps from either a 3‐bromo indole ester using the Suzuki reaction or from a 3‐keto substituted indole ester. N‐Alkylation of ethyl indole‐2‐carboxylate, followed by amidation and catalytic addition of 9‐hydroxyxanthene gave a 3‐xanthyl‐indole‐2‐carboxamide analog and a spiropyrrolo indole as a side product.
Further studies on polycyclic arene sulfides. Preparation and mutagenic activity of 9, 10, 10a, 11a‐tetrahydrotriphenyleno[1,2‐b]‐thiirene, 1a,2,3,10b‐tetrahydro‐5H‐thiereno[3,4]benzo[1,2‐b]fluorene and 1a,2,3,11b‐tetrahydroacenaphtho[1′,2′:6,7]naphth[1,2‐b]thiirene
Authors: Blum Jochanan , Kogan Vladimir , Glatt Hansruedi
Published: March 2009

The title compounds 6, 8 and 10, which are dihydroarene sulfides of the environmental pollutants triphenylene, benzo[b]fluorene and benzo[k]fluoranthene, have been synthesized from the corresponding epoxides and N,N‐dimethylthioformamide. The mutagenicity of the episulfides has been investigated using Salmonella typhimurium strains TA98 and TA100. While compounds 6 and 10 were mutagenic, the tetrahydrobenzo[b]fluorene episulfide 8 was inactive.
Synthesis of 9‐[2‐(2‐hydroxymethyl‐2‐methyl‐, ‐(2‐acetoxymethyl‐2‐methyl‐, ‐(2,2‐di(hydroxymethyl)‐, and ‐(2,2‐Di(acetoxymethyl)‐1,3‐dioxan‐5‐yl)ethyl] derivatives of guanine and 2‐aminopurine
Authors: Kim Dae‐Kee , Lee Namkyu , Kim Young‐Woo
Published: March 2009

Synthesis of 9‐[2‐(2‐hydroxymethyl‐2‐methyl‐, ‐(2‐acetoxymethyl‐2‐methyl‐, ‐(2,2‐di(hydroxymethyl)‐, and ‐(2,2‐di(acetoxymethyl)‐1,3‐dioxan‐5‐yl)ethyl] derivatives of guanine and 2‐aminopurine,2–9, has been accomplished in seven to eight step sequences from readily available 1‐(tert‐butyldiphenylsilyloxy)‐acetone, 1,3‐di(tert‐butyldiphenylsilyloxy)acetone, and the diol10. Formation of cyclic ketals11and12was carried out successfully under an acidic condition using a catalytic amount of methanesulfonic acid along with excess anhydrous copper(II) sulfate in toluene. Subsequent reactions of desilylation, acetylation, hydrogenolysis, and bromination afforded the key intermediates19and20, which were coupled with 2‐amino‐6‐chloropurine to produce the purine compounds21and22in good yields. Guanine derivatives2–5were obtained from21and22by hydrolysis and acetylation, while the dechlorination and hydrolysis of21and22yielded the 2‐aminopurine compounds6–9.
Facile syntheses of homothia‐ and homoazacalixarenes
Authors: Ito Kazuaki , Nagai Takanori , Ohba Yoshihiro , Sone Tyo
Published: March 2009

Decahomotetrathiacalix[6]arenes were conveniently prepared from the 2:2 cyclization reactions of bis(chloromethyl)phenol‐formaldehyde trimers with 1,2‐ethanedithiol in high yields. In contrast, the simi lar reactions of the trimers with 1,3‐propanedithiol instead of 1,2‐ethanedithiol gave 1:1 macrocycles, hexahomodithiacalix[3]arenes, in good yields. Homoazacalixarenes were also prepared from the analogous reactions using piperazines. These macrocycles adopt a cone‐like form as a preferable conformation in solution.
Total syntheses of (±)‐cis‐ and trans‐11‐methoxydeethyleburnamonine
Authors: Rönkkö Kalle , Berner Mathias , Jokela Reija , Tolvanen Arto
Published: March 2009

The total syntheses of 11‐methoxydeethyleburnamonines (4) and (13) were carried out with use of 6‐methoxytryptophyl bromide (5) as starting material. Compound 5 was converted in three steps to trans‐ester 8. Acid‐catalysed epimerization of 8, lithium aluminum hydride reduction of the ester group, tosylation and substitution with cyanide gave the cis‐nitrile 12. Acid‐induced cyclization of 12 yielded mainly (±)‐trans‐11‐methoxydeethyleburnamonine (13), whereas base‐induced cyclization gave (±)‐cis‐11‐methoxydeethyleburnamonine (4).
New synthetic approaches to bridgehead nitrogen heterocycles. Derived from 3‐amino‐2,3‐dihydro‐5,6‐dimethyl‐2‐thioxothieno[2,3‐d]pyrimidin‐4(1H)‐one and its salts
Authors: Santagati Andrea , Modica Maria , Santagati Maria
Published: March 2009

Bridgehead nitrogen heterocycles 3a, b and 6a, b containing the thieno‐pyrimidine system have been prepared from the versatile intermediates 3‐amino‐2,3‐dihydro‐5,6‐dimethyl‐2‐thioxo‐thieno[2,3‐d]pyrimidin‐4‐(1H)‐one 1 and its hydrazinium or potassium salts 4; their structural elucidation is also reported.
Synthesis of acyclic nucleoside phosphonates as antiviral compounds
Authors: Wormstädt Frank , Gütschow Michael , Eger Kurt , Brinckmann Ute
Published: March 2009

Reaction of 6‐chloropyrimidines with diethyl [(2‐aminoethoxy)methyl]phosphonate allows for a ready access to acyclic nucleoside phosphonates. A series of 5‐substituted pyrimidines bearing a phosphonate side chain at position 6 were synthesized and tested against herpes simplex viruses (HSV‐1 and HSV‐2) and human immunodeficiency virus (HIV‐1). Some compounds showed weak antiviral activity against HSV‐1.
One‐Pot synthesis of isothiachromene, isochromene, isoquinoline and tetrahydronaphthalene derivatives
Authors: El‐Sayed A. M. , Abdel‐Ghany H.
Published: March 2009

A new series of tetrahydronaphthalene, isothiachromene, isochromene and isoquinoline derivatives were synthesized by reacting cyclohexylidenemalononitrile with active nitriles, active halo compounds, carbon disulfide, aldehydes, isothiocyanates and isocyanates, respectively.
A convenient synthesis of pyrazolo[3,4‐d]pyrimidine‐4,6‐dione and pyrazolo[4,3‐d]pyrimidine‐5,7‐dione derivatives
Authors: El Haddad M. , Soukri M. , Lazar S. , Bennamara A. , Guillaumet G. , Akssira M.
Published: March 2009

Pyrazolo‐[3,4‐d]pyrimidine‐4,6‐diones 5 and pyrazolo[4,3‐d]pyrimidine‐5,7‐diones 7 were synthesized by Curtius rearrangement of pyrazolic mono‐esters 2 and 3 followed by hetero‐cyclization via the ureas derivatives 4 and 6 under alkaline conditions.
Synthesiss of novel 3‐(2‐thienyl)‐1,2‐diazepino[3,4‐b]quinoxalines with algicidal activity
Authors: Kim Ho Sik , Jeong Geuk , Lee Hyoung Choul , Kim Jin Hee , Park Yong Tae , Okamoto Yoshihisa , Kajiwara Shinnosuke , Kurasawa Yoshihisa
Published: March 2009

The reaction of the quinoxaline N‐oxide 1 with thiophene‐2‐carbaldehyde gave 6‐chloro‐2‐[1‐methyl‐2‐(2‐thienylmethylene)hydrazino]quinoxaline 4‐oxide 5, whose reaction with 2‐chloroacrylonitrile afforded 8‐chloro‐2,3‐dihydro‐4‐hydroxy‐1‐methyl‐3‐(2‐thienyl)‐1H‐1,2‐diazepino[3,4‐b]quinoxaline‐5‐carbonitrile 6. The reaction of compound 6 with various alcohols in the presence of a base effected alcoholysis to provide the 5‐alkoxy‐8‐chloro‐2,3,4,6‐tetrahydro‐1‐methyl‐4‐oxo‐3‐(2‐thienyl)‐1H‐1,2‐diazepino[3,4‐b]‐quinoxalines 7a‐d. The reaction of compounds 7a and 7b with diethyl azodicarboxylate effected dehydrogenation to give the 5‐alkoxy‐8‐chloro‐4,6‐dihydro‐1‐methyl‐4‐oxo‐3‐(2‐thienyl)‐1H‐1,2‐diazepino[3,4‐b]‐quinoxalines 8a and 8b, respectively. Compounds 8a and 8b were found to show good algicidal activities against Selenastrum capricornutum and Nitzchia closterium.
Synthesis of new bis(2,4‐dimethyl‐5‐amino‐benzo[b][1,8]‐naphthyridines) and bis(benzo[b][1,8]naphthyridones) linked with methylene linear chain
Authors: Afloroaei Cerasella , Dulamita Nicu , Vlassa Mircea , Barbe Jacques , Brouant Pierre
Published: March 2009

The preparation of novel alkyl monobridged 2,4‐dimethyl‐5‐amino‐benzo[b][1,8]naphthyiridine and benzo[b][1,8]naphthyridone derivatives by phase transfer catalysis is reported.
Syntheses of 2,3‐dicyano‐5a,8a‐dihydro‐5a‐hydroxycyclopentano[1′,2′:4,5]pyrrolo[2,3‐b]pyrazines and 2,3‐dicyanocyclohexano[1′,2′:4,5]pyrrolo‐[2,3‐b]pyrazines
Authors: Shirai Kazuko , Fukunishi Koushi , Hou Dongfeng , Matsuoka Masaru
Published: March 2009

Previously synthesized 2‐(3′‐chloro‐5′,6′‐dicyanopyrazin‐2′‐yl)cyclopentan‐1‐one 1, obtained from the reaction of 2,3‐dichloro‐5,6‐dicyanopyrazine with 1‐pyrrolidino‐1‐cyclopentene, was further reacted with primary alkylamines to give mixtures of diastereomer of 5‐alkyl‐2,3‐dicyano‐5a,8a‐dihy‐dro‐5a‐hydroxycyclopentano[1′,2′:4,5]pyrrolo[2,3‐b]pyrazines 3a‐h in high yield. The reaction of 2‐alkylamino‐3‐chloro‐5,6‐dicyanopyrazine with 1‐pyrrolidino‐1‐cyclohexene gave 5‐alkyl‐2,3‐dicyanocyclopentano[1′,2′:4,5]pyrrolo[2,3‐b]pyrazines 5a‐b together with 5‐alkylamino‐2,3‐dicyano‐6‐pyrrolidinopyrazines 6a‐b. The products prepared are all of interest as potential pesticides and new fluorescent chromophores.
Synthesis of new C2 symmetrical dibenzospirodiamide and dibenzospirodiamine as potential chiral auxiliaries and building blocks of ionophores
Authors: Choi Heung‐Jin , Park Yang Jin , Kim Moon Goo , Park Yeon Sil
Published: March 2009

2,8‐Diazadibenzo[c,i]spiro[5,5]undecan‐1,7‐dione 3 are synthesized via reaction of malonic ester with 2‐nitrobenzyl bromide, followed by reduction‐cyclization in 86% overall yield. 2,8‐Diazadibenzo[c,i]‐spiro[5,5]undecane 4 was obtained by reduction of 3 with LiAIH4 in 90% yield. N‐Alkylation of 3 with various alkylating reagents is studied.
Convenient one‐pot syntheses of pyrazoles from imines, a vilsmeier type reagent and hydrazine
Authors: Katritzky Alan R. , Denisenko Anna , Denisenko Sergey N. , Arend Michael
Published: March 2009

A simple one‐pot procedure for the regioselective synthesis of pyrazoles from readily available starting materials is described. Vilsmeier type reagent 1 reacts with imines 10 (via the corresponding tautomeric secondary enamines) in tetrahydrofuran to give enaminoimine hydrochlorides 11. Nonsymmetrical imines generally react preferentially with 1 at the sterically less hindered α‐position. The enaminoimine hydrochlorides 11 are transformed in situ to the corresponding pyrazoles 12 in moderate to high yields by the addition of hydrazine.
Selenium heterocycles XLIV. Syntheses of 8,9‐dihydro‐1,2,3‐thiadiazolo[4,5‐a]‐4,7‐dihydroxynaphthalene and 1,2,3‐selenadiazolo[4,5‐a]‐4,7‐dimethoxynaphthalene
Authors: Shafiee A. , Jalilian A. R. , Rezaei M.
Published: March 2009

The reaction of thionyl chloride with the semicarbazone 2 gave 4,5‐dihydro‐6,9‐dihydroxynaphtho‐[1,2‐d][1,2,3]thiadiazole (3) instead of 4,5‐dihydro‐6,9‐dimethyoxynaphtho[1,2‐d][1,2,3]thiadiazole (4). Selenium dioxide oxidation of compound 2 gave 4,5‐dihydro‐6,9‐dimethyoxynaphtho[1,2‐d][1,2,3]selenadiazole (5). Oxidation of compound 5 with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone afforded 6,9‐dimethyoxynaphtho[1,2‐d][1,2,3]selenadiazole (6).
Carbocyclic 5′‐norcytidine (5′‐norcarbodine)
Authors: Hegde Vishnumurthy R. , Seley Katherine L. , Schneller Stewart W.
Published: March 2009

A preparation of (1′R,2′S,3′R,4′S)‐1‐(2′,3′,4′‐trihydroxycyclopent‐1′‐yl)‐lH‐cytosine (5′‐norcarbodine, 3) has formally been achieved in 2 steps from (+)‐(1R,4S)‐4‐hydroxy‐2‐cyclopenten‐1‐yl acetate (4) and cytosine. The L‐like enantiomer of 3 (that is, 6) is also reported using the enantiomer of 4 (that is, 7). In evalu ating 3 and 6 for antiviral potential against a number of viruses, compound 3 was found to have activity towards Epstein‐Barr virus (EBV).
Novel and efficient one‐pot synthesis of azuleno[1,2‐b]‐benzothiophenic enones from the corresponding 2‐cycloheptatrientyl‐3‐(2‐furyl)benzothiophenes
Authors: Houda Yuuko , Sasabe Misako , Bo Xu , Takagi Hideki , Yamamura Kimiaki
Published: March 2009

2‐Cycloheptatrienyl‐3‐(2‐furyl)benzothiophenes, which are prepared by Stille coupling reaction of 2‐cyclo‐heptatrienyl‐3‐bromobenzothiophene with the 5‐substituted 2‐trimethylstannylfurans, react with triphenylmethyl tetrafluoroborate to give the corresponding azuleno[1,2‐b]benzothiophenic enones in excellent yields.
Synthesis and stereochemical studies of 2‐substituted thiazolidine‐4‐carboxamide derivatives
Authors: Refouvelet Bernard , Pellegrini Nadia , Robert Jean‐François , Crini Gregorio , Blacque Olivier , Kubicki Marek M.
Published: March 2009

A series of new 2‐substituted thiazolidine‐4‐carboxamide derivatives which have potentially useful immunological properties, have been synthesized in a stereoselective manner by coupling 2‐subsituted thiazolidine‐4‐carboxylic acids with amines or amino esters. The structure of these compounds was established by combination of NMR methods and by X‐ray analysis.
Photochromic fulgides: Transformation of the non‐photochromic (Z)‐isomer of a fulgide into a highly photochromic (E)‐isomer via structural modification involving enhanced conjugation
Authors: Sun Zhiyuan , Hosmane Ramachandra S. , Tadros Maher
Published: March 2009

The non‐photochromic fulgide (1‐Z) has been successfully converted into the highly photochromic (3‐Z) analogue. A dicyanomethylene group was introduced at the 5‐position of 1‐Z in order to enhance the latter's conjugation properties that would facilitate the photochemical Z→E isomerization process. The irradiation of the product 3‐Z with a UV light at λmax 350 nm formed a bluish green solution which absorbed at λmax 620 nm, corresponding to the ring‐closed product 4. The latter was also formed from the reference dicyanomethylene product 3‐E synthesized from 1‐E. The irradiation of 4 at λmax 532 nm produced the reversion to the original pale yellow color of 3‐E.
2,4,6‐trichloropyrimidine. Reaction with anilines
Authors: Schomaker Jennifer M. , Delia Thomas J.
Published: March 2009

The reaction of 2,4,6‐trichloropyrimidine 1 with a variety of 4‐substituted anilines 2 has been investigated. Monosubstitution occurs readily for all anilines except those containing strongly electron‐withdrawing groups. The yields of the isomeric products 3 and 4 parallel the Hammet constants of the ring substituents. The main product when ethanol was used as the solvent was the 4‐substituted‐2,6‐dichloropyrimidine 3. Spectral and X‐ray data confirmed this assignment. However, a solvent dependence on the 3:4 ratio was demonstrated. In some cases, excess aniline under forcing conditions led to 2,4‐disubstituted products.
Syntheses and properties of tetraaza‐, diaza‐, tetraoxa‐, and dioxa‐metacyclophanes
Authors: Ito Kazuaki , Ohba Yoshihiro , Shinagawa Eita , Nakayama Satoshi , Takahashi Shigemi , Honda Katsuhiko , Nagafuji Hidekazu , Suzuki Akane , Sone Tyo
Published: March 2009

Metacyclophanes were prepared by cyclization reactions between bis(chloromethyl) compounds and piperazine, primary amines, or ethylene glycol. The 1H nmr relaxation time (T1) measurements indicated that the macrocycles feature the up and down motion of the aromatic units around the XCH2Ar (X = N, O) methylene moieties as the axes. Metacyclophanes incorporating piperazine units showed high complexation ability for alkaline metal cations.
Studies on isocyanides and related compounds. Synthesis of furan derivatives and their transformation into indole derivatives
Authors: Marcaccini Stefano , Pepino Roberto , Marcos Carlos F. , Polo Cecilia , Torroba Tomás
Published: March 2009

The intramolecular Knoevenagel condensation ofN‐cyclohexyl 3‐aryl‐2‐(2‐nitrophenyl)acetoxy‐3‐oxopropionamides 4 obtained from 2‐nitrophenylacetic acid (1), arylglyoxals 2 and cyclohexyl isocyanide (3) affordedN‐cyclohexyl 3‐aryl‐2,5‐dihydro‐2‐(2‐nitrophenyl)‐5‐oxofuran‐2‐carboxamides 6 which underwent reductive cleavage toN‐cyclohexyl (Z)‐3‐aryl‐2‐hydroxy‐3‐(2,3‐dihydro‐2‐oxoindol‐3‐ylidene)propionamides 8 probablyviathe labile intermediates 7.
Preparation of thiochromans via thermal cyclization
Authors: Jensen Anton W. , Manczuk Joan , Nelson David , Caswell Onalee , Fleming Steven A.
Published: March 2009

Formation of the thiochroman ring system is achieved by a two step synthesis that involves heating 3‐thiophenyl‐1‐propanols or 4‐thiophenyl‐2‐butanols in toluene with catalytic amounts of p‐toluenesulfonic acid. The propanols are made by the addition of sulfur stabilized carbanions to styrene oxide, ethylene oxide, propylene oxide, and isobutylene oxide. The carbanions are generated by treatment of either benzyl phenyl sulfide or thioanisole with butyllithium. The effect of substitution at the 1 and 3 positions of the propanols on the reaction yields is discussed. The mechanism of the reaction apparently involves intramolecular electrophilic aromatic substitution rather than a Claisen or thio‐Claisen rearrangement.
Oxidant promoted 1,3‐dipolar cycloaddition of benzimidazolium ylides to alkenes for preparation of 4H‐pyrrolo[1,2‐a]benzimidazole
Authors: Wang Bingxiang , Hu Jiaxin , Zhang Xuechun , Hu Yuefei , Hu Hongwen
Published: March 2009

An oxidant promoted 1,3‐dipolar cycloaddition of benzimidazolium ylides to alkenes was developed for the preparation of 4H‐pyrrolo[1,2‐a]benzimidazole derivatives in moderate yields under mild conditions. In the presence of a suitable oxidant, the most commercially available “normal” alkenes, instead of alkynes or “abnormal” alkenes, could be used as dipolarophiles successfully. Moreover, CrO3/Et3N has been proved to be a more effective dehydrogenating reagent than MnO2 or tetrakispyridine cobalt (II) dichromate (TPCD) in this procedure.
Experimental and theoretical structural study of 2‐pyridyl‐ and 4‐hydroxyphenyl‐1,4‐dihydropyridine derivatives
Authors: De Armas Héctor Novoa , Blaton Norbert , Peeters Oswald M. , De Ranter Camiel , Suárez Margarita , Rolando Emilio , Verdecia Yamila , Ochoa Estael , Martín Nazario , Quinteiro Margarita , Seoane Carlos , Soto José L.
Published: March 2009

A series of substituted 1,4‐dihydropyridines (1,4‐DHPs) has been synthesised following the well‐known Hantzsch's procedure for symmetrical 1,4‐DHP. The structures of these compounds have been thoroughly studied by X‐ray crystallographic analysis and semiempirical (AMI) calculations. A good agreement is found between the theoretical and experimental results. In all cases, the most stable conformation fulfils all the requirements needed for exhibiting an antagonist calcium effect.
Reaction of chloropyridazines with N,N‐dimethylformamide
Authors: Lee Woo Song , Yoon Yong‐Jin , Kim Sung‐Kyu
Published: March 2009

Chloropyridazine derivatives 1, 3, 5, 7 and 10a‐c were reacted with N,N‐dimethylformamide under reflux condition to give the corresponding N,N‐dimethylaminopyridazines 2, 4, 6, 8, 9 and 11a‐c regio‐selectively.
Synthesis of 3‐(2‐benzyloxy‐6‐hydroxyphenyl)‐1‐methylpyrazoles by the reaction of chromones with methylhydrazine
Authors: Pinto Diana C. G. A. , Silva Artur M. S. , Cavaleiro José A. S.
Published: March 2009

The 3‐(2‐benzyloxy‐6‐hydroxyphenyl)‐5‐(methyl, phenyl or styryl)pyrazoles were prepared from the reaction of 2‐(methyl, phenyl or styryl)chromones with methylhydrazine. The structure of these compounds has been determined by several nmr techniques, and the reaction mechanism is discussed.
Reaction of pyrroles with naphthoquinones. Synthesis of new pyrrolylnaphthoquinone dyes
Authors: Lion Claude , Baudry Richard , Hedayatullah Mir , Da Conceição Louis , Hocquaux Michel , Genard Sylvie , Maignan Jean
Published: March 2009

The reaction of 1,4‐naphthoquinone (1) with N‐alkylpyrroles (2) gives a mixture of 2‐(pyrrol‐2‐yl)‐1,4‐naphthoquinones (3) and 2,5‐bis(1,4‐naphthoquinon‐2‐yl)pyrroles (4). The yields and the ratios of these two products depend greatly on the experimental conditions. The reaction has been extended to 5‐hydroxy‐1,4‐naphthoquinone (juglone, 5) and 1,2‐naphthoquinone (6). New pyrrolylnaphthoquinones are obtained.
Dipolar 1,3‐cycloaddition of arylnitriloxides on 1,2‐dihydroisoquinolines in a two‐phase medium
Authors: Kitane Said , Taimi Amina , Bahloul Abdelmejid , Sebban Abdelfatah , Berrada Mohamed , Joly Jean‐Pierre
Published: March 2009

The 1,3‐dipolar cycloaddition of arylnitriloxides on 1,2‐dihydroisoquinoline derivatives led to new 3‐aryl, 3a‐8,9,9a‐tetrahydro[5,4‐c]‐isoxazoloisoquinoline adducts. The regioselectivity of the cycloaddition reactions is discussed on the basis of 1H and 13C NMR data.
Total synthesis of homalicine and its related dihydro aglycon
Authors: Zamani Khosrow , Rama Nasim Hassan , Iqbal Rashid
Published: March 2009

The condensation of homophthalic acid (1) with 3‐methoxybenzoyl chloride, followed by demethylation gave 3‐(3‐hydroxyphenyl)isocoumarin (3b). Reaction of (3b) with α‐tetraacetobromo glucose yielded tetraacetylhomalicine (3d), which was deacetylated to homalicine (3e).
Syntheses of 2,4‐diaryl‐2,3‐dihydro‐1,5‐benzothiazepines
Authors: Katritzky Alan R. , Rogovoy Boris V. , Chassaing Christophe , Vvedensky Vladimir , Forood Behrouz , Flatt Brenton , Nakai Hisao
Published: March 2009

The condensation of α,β‐unsaturated ketones with substituted o‐aminothiophenols, obtained by reductive cleavage of the corresponding disulfides in the presence of triphenylphosphine, is an effective method for the synthesis of 2,4‐diaryl‐2,3‐dihydro‐1,5‐benzothiazepines under neutral conditions.
A facile synthesis of 2,7‐diazapyrene
Authors: Sotiriou‐Leventis Chariklia , Mao Zhan
Published: March 2009

2,7‐Diazapyrene is synthesized in three high‐yield steps from commercially available 1,4,5,8‐naphthalene tetracarboxylic dianhydride, which first reacts with concentrated ammonium hydroxide solution at room temperature to give 1,4,5,8‐naphthalenetetracarboxylic diimide (96%). The latter compound is subsequently reduced with borane in refluxing tetrahydrofuran to give 1,2,3,6,7,8‐hexahydro‐2,7‐diazapyrene (77%), which in turn is oxidized with manganese dioxide in refluxing benzene giving 2,7‐diazapyrene (71%).