bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the reactivity of some N‐aryl‐ and N‐heteroaryl‐N'‐alkylthioureas towards electrophilic reagents. Synthesis of new N‐pyridylthioureas and thiazolines maría
Authors: Rodríguez‐Franco Isabel , Dorronsoro Isabel , Martínez Ana , Castro Ana 
Published: March 2009

AbstractHere in we describe our findings about the behaviour of some N‐aryl‐ and N‐heteroaryl‐N'‐alkylthioureas towards electrophilic reagents. In acid medium, the treatment of thioureas bearing aryl groups with 4‐chloropyridine in 2‐propanol yielded N‐aryl‐N‐(4‐pyridyl)‐N'‐alk;ylthioureas and N‐aryl‐N'‐alkylureas, whereas the heteroarylthioureas tested under similar reaction conditions afforded N‐heteroaryl‐N'‐alkyl‐O‐(2‐propyl)isoureas. The reaction of N‐(5,6,7,8‐tetrahydronaphth‐1‐yl)‐ and N‐(2‐benzimidazolyl)‐N'‐butyl‐thiourea with propargyl bromide in acid medium led to the formation of 2‐butylimino‐3‐arylthiazolines, in a regioselective way. However, when this reaction was carried out in basic conditions the regioselectivity failed and a mixture of isomeric thiazolines was obtained. The Z‐ or E‐configuration of the imino group of the synthesized thiazolines was studied by molecular modelling and by selective nuclear Overhauser experiments in nuclear magnetic resonance.
Synthesis of unsymmetrical methylene derivatives of benzopyran‐4‐ones from mannich bases
Authors: Mazzei Mauro , Dondero Ramona , Balbi Alessandro , Bonora Gian Maria 
Published: March 2009

AbstractThe formation of methylene‐bis derivatives of benzopyran‐4‐ones from their Mannich bases was studied. On these grounds, unsymmetrical methylene derivatives have been synthesized by reacting Mannich bases of benzopyran‐4‐ones with structurally related compounds lacking the dialkylaminomethyl group.
One‐step preparation of some 2‐isopropenyl‐2,3‐dihydronaphtho‐[2,3‐b]furan‐4,9‐diones
Authors: Yamaguchi Seiji , Katsuki Toshiharu , Yokoyama Hajime , Hirai Yoshiro 
Published: March 2009

AbstractSome 2‐isopropenyl‐2,3‐dihydronaphtho[2,3‐b]furan‐4,9‐diones la‐f,b',f were prepared by one‐step cyclizations of 2‐hydroxy‐1,4‐naphthoquinones 2a‐f with 1,4‐dibromo‐2‐methyl‐2‐butene (3).
A study of the reaction between 2,4‐disubstituted‐2,3‐dihydro‐1,5‐benzothiazepines and ketenes generated in situ from chloro and dichloroacetyl chlorides
Authors: Xing Qi‐Yi , Wang Hong‐Zhong , Zhou Xin , Jin Sheng , Li Yue‐Ming , Chan Albert S. C. 
Published: March 2009

AbstractIn the presence of triethyl amine, the reaction of 2,4‐disubstituted‐2,3‐dihydro‐1,5‐benzothiazepine with chloro and dichloroacetyl chlorides produced not only the expected β‐lactam derivative of the benzo‐thiazepine, but also the ring opening product. Different results were obtained when the substituent at 2‐position of the benxothiazepine varied from methyl to aryl, and the substituent on the chloroacetyl chloride varied from H to Cl, or when carrying out the reaction at different temperatures. The structures of the obtained products and the reaction mechanism are discussed.
Concise synthesis of 6‐sulfonylated 3,4‐dihydro‐2h‐thiopyrans and 7‐sulfonylated 3,4,5,6‐tetrahydrothiepines from lactols
Authors: Gallos John K. , Dellios Constantinos C. 
Published: March 2009

AbstractA concise method for the synthesis of the title compounds has been developed, which involves condensation of lactols with methylthiomethyl p‐tolyl sulfone, followed by mesylation and further cyclisation of the elimination products by refluxing with excess of sodium iodide in dimethyl formamide (DMF).
Synthesis and complexing properties of double armed diaza‐15‐crown‐5 and diaza‐18‐crown‐6 ethers having 4′‐hydroxy‐3′,5′‐disubstituted benzyl groups
Authors: Habata Yoichi , Saeki Tomomi , Akabori Sadatoshi 
Published: March 2009

AbstractA series of double armed diaza‐15‐crown‐5 ethers (9a ‐ 16a) and diaza‐18‐crown‐6 ethers (9b ‐ 16b) have been prepared by the Mannich reaction of 2,6‐disubstituted phenols with the corresponding N,N'‐dimethoxymethyldiaza‐crown ethers in benzene. The crystal structures of the diaza‐18‐crown‐6 ethers having iso‐propyl (10b), tert‐butyl (11b), and mixed methyl and tert‐butyl groups (12b) at positions 3′ and 5′ of the phenolic side arms were determined using X‐ray diffraction methods. Competitive transport by these ligands for sodium, potassium and cesium cations were measured under basic‐source phase and acidic‐receiving phase conditions.
Facile synthesis of 3‐substituted [1,2,4]triazino[3,4‐f]purine‐4,6,8‐trione derivatives
Authors: Settimo Federico Da , Marini Anna Maria , Pardi Gianluca , Primofiore Giampaolo , Salerno Silvia , Simorini Francesca 
Published: March 2009

AbstractA new synthetic route to build the [1,2,4]triazino[3,4‐ f]purine nucleus is described. The novel [1,2,4]‐triazino[3,4‐ f]purine‐4,6,8(l H,7 H,9 H)‐trione derivatives were obtained by condensation of 8‐hydrazinotheophylline with appropriate glyoxylic acids via the intermediate hydrazones.
Synthesis and chemiluminescent activity of 8,9‐dihydrobenzo[g] pyridazino[4,5‐b]indole‐7,10(11H)‐diones
Authors: Kurumi Masateru , Sasaki Kenji , Takata Hiroko , Nakayama Taiji 
Published: March 2009

AbstractSubstituted and unsubstituted naphthylamines were transformed into the corresponding triazole derivatives, which were converted to dimethyl 1H‐benz[g]indole‐2,3‐dicarboxylates by photocyclization. The reaction of the diesters with hydrazine hydrate gave the corresponding 8,9‐dihydrobenzo[g]‐pyridazino[4,5‐b]indole‐7,10(11H)‐diones (5). One of compounds 5 was found to have chemiluminescent activity similar to luminol.
Synthesis of 2(3H)‐benzoxazolone and 2(3H)‐benzothiazolone derivatives as potential beta‐3‐adrenergic receptor ligands (part 2)
Authors: Delhomel J. F. , Yous S. , Depreux P. , Lesieur D. 
Published: March 2009

AbstractAdrenoceptors beta‐3‐subtype mediate lipolysis and in the search for potential beta‐3‐adrenergic receptors agonists for the treatment of obesity, we designed new arylethanolamines (structures 4, 5) and aryloxypropanolamines (structures 6, 7) derived from 2(3H)‐benzoxazolone and 2(3H)‐benzothiazolone.
Synthesis of herbicidal 3‐substituted‐4(3H)‐pyrimidinones under high pressure
Authors: Jezewski Artur , Jurczak Janusz , Lidert Zev , Tice Colin M. 
Published: March 2009

AbstractThe reaction of an N‐monosubstituted amidine with a β‐ketoester to afford a pyrimidinone is sluggish at best under normal conditions. We now report that this reaction can be effected in moderate yield under high pressure. Thus, 2,6‐dichloro‐4‐pyridyl‐(N‐prop‐2‐ynyl)carboxamidine (4b) was reacted with three α‐substituted‐β‐ketoesters (2b‐d) at 10–16 kbar to afford herbicidal 2‐(2,6‐dichloro‐4‐pyridyl)‐3‐(prop‐2‐ynyl)‐4(3H)‐pyrimidinones 5b and 5c in 15 ‐ 43% yield. This result expands the scope of reactions promoted by application of high pressure.
A practical synthesis of functionalized alkyl‐oligothiophenes for molecular self‐assembly
Authors: Michalitsch R. , Elkassmi A. , Yassar A. , Gamier F. 
Published: March 2009

AbstractA synthesis for oligothiophenes that carry an alkyl sidechain with a terminal thiol group is presented. The procedure consists of three basic steps and uses well‐known and simple synthetic chemistry. Nevertheless, this strategy for preparing functionalized oligothiophenes provides overall yields that are as high as 25–30% and represents a convenient route towards this interesting class of materials.
Synthesis of some novel 3,7‐dimethyl‐4H‐pyrazolo[5,1‐c][1,2,4]triazin‐4‐ones
Authors: El‐Barbary Ahmed A. , El‐Badawi Mahmoud A. , Loksha Yasser M. 
Published: March 2009

AbstractSome novel 3,7‐dimethyl‐6H‐pyrazolo[5,1‐c][1,2,4]triazin‐4‐ones were prepared (3a‐g). Compounds 3a,b were treated with hydrazines to afford various products 7a,b, 8a,b, 9 and lla,b depending on the type of hydrazine derivative and reaction conditions. The benzoyloxyimino‐pyrazolo[5,1‐c][1,2,4]triazines (13a,b) were synthesized by refluxing of compounds 3a,b with hydroxylamine hydrochloride to afford the corresponding oxime derivatives followed by treatment with benzoyl chloride.
Synthesis and biological evaluation of several 3‐(coumarin‐4‐yl)tetrahydroisoxazole and 3‐(coumarin‐4‐yl)dihydropyrazole derivatives
Authors: Emmanuel‐Giota Anne A. , Fylaktakidou Konstantina C. , Litinas Konstantinos E. , Nicolaides Demetrios N. , Hadjipavlou‐Litina Dimitra J. 
Published: March 2009

AbstractA series of novel 3‐(coumarin‐4‐yl)tetrahydroisoxazoles 5a,b, 7, 9 and 3‐(coumarin‐4‐yl)dihydropyra‐zoles 13a‐d, 14,15a,b were synthesized from coumarin‐4‐carboxaldehyde 1 via the intermediate N‐methyl nitrone 3 and N‐phenyl or N‐methyl hydrazones 11a,b. These coumarin derivatives were isolated, characterized and evaluated in vitro for their ability to inhibit trypsin, β‐glucuronidase, soybean lipoxygenase and to interact with the stable radical 1,1‐diphenyl‐2‐picrylhydrazyl. The compounds were tested in vivo as anti‐inflammatory agents in the rat carrageenin paw edema assay. Compound 15a seems to be a lead molecule to be modified in order to improve the lipoxygenase inhibition. The results are discussed in terms of structural characteristics.
One pot synthesis of 6,12‐dihydro‐1,3,7,9‐tetramethyl‐5H, 11H‐dipyrido[1,2‐a:1′,2′‐d]pyrazine‐2,8‐dione by hilbert‐johnson reaction of 2‐chloromethyl‐3,5‐dimethyl‐4‐methoxypyridine
Authors: Orešić Marina , Danilovski Aleksandar , Dumić Miljenko , Košutić‐Hulita Nada 
Published: March 2009

AbstractBy heating 2‐chloromethyl‐3,‐5‐dimethyl‐4‐methoxypyridine (1) either neat or in solution methoxy group cleavage was achieved, followed by dimerisation to poorly soluble 6,12‐dihydro‐1,3,7,9‐tetramethyl‐5H,11H‐dipyrido[1,2‐a:1′,2′‐d]pyrazine‐2,8‐dione (3) in almost quantitative yield with methyl chloride evolution. To our knowledge this is the first example of such Hilbert‐Johnson preparation of dipyridopyrazine‐diones. Recrystallization of 3 from the hydrochloric acid yielded 6,12‐dihydro‐2,8‐dihydroxy‐1,3,7,9‐tetramethyl‐dipyrido[1,2‐a:1′,2′‐d]pyrazinediylium dichloride (4), neutralization of which gave back the pyrazine‐2,8‐dione 3. The molecular structures of both compounds 3 and 4 have been unambiguously confirmed by single crystal X‐ray structure analysis.
Spectroscopic analysis of imidazolidines. Part II: 1H NMR spectroscopy and conformational analysis of 1,2 and 1,3‐diarylimidazolidines
Authors: Salemo Alejandra , Buldain Graciela , Perillo Isabel A. 
Published: March 2009

Abstract1H NMR spectra of a series of 1,2 and 1,3‐diarylimidazolidines are analyzed and correlated with their conformational features. Results were interpreted on the basis of chemical shifts and coupling constants of hydrogen atoms and confirmed by ID nOe difference experiments. 1,3‐Diarylimidazolidines (1–7) show a fast inversion of the N‐aryl nitrogen in all studied cases. 1,2‐Diaryl‐3‐methyl (or benzyl) imidazolidines (8–13) display a preferential conformation with a transoid orientation of N3 and C2 substituents.
Preparation of pyrrolo[2,1,5‐cd]indolizine Derivatives by intramolecular condensation of 3‐acyl‐5‐methylindolizines
Authors: Liang Feng , Hu Jiaxin , Zhang Lande , Hu Yuefei , Hu Hongwen 
Published: March 2009

AbstractAn efficient two step route has been developed to synthesize pyrrolo[2,1,5‐cd]indolizine derivatives. The reaction sequence proceeds via preparation of 3‐acyl‐5‐methylindolizines followed by an intramolecular condensation. The procedures were carried out under convenient conditions and gave the products in high yields. It could be expected to be used to prepare a broad range of potentially interesting pyrrolo[2,1,5‐cd]indolizine derivatives.
Reactions of alkyl (z)‐2‐[(E)‐2‐ethoxycarbonyl‐2‐(2‐pyridinyl)‐ethenyl]amino‐3‐dimethylaminopropenoates with C‐ and N‐nucleophiles. the synthesis of fused pyranones, pyridinones and pyrimidinones
Authors: Jukić Lucija , Svete Jurij , Stanovnik Branko 
Published: March 2009

AbstractAlkyl 2‐[2‐ethoxycarbonyl‐2‐(2‐pyridinyl)ethenyl]amino‐3‐dimethylaminopropenoates 3 and 4 were transformed with C‐and N‐nucleophiles into β‐heteroaryl‐α,β‐didehydro‐α‐amino acid derivatives 13‐16, substituted 3‐amino‐4H‐quinolizin‐4‐one 17, 2H,5H‐benzo[b]pyran‐2,5‐dione 18 and 19, 2H,5H‐pyrano[4,3‐b]pyran‐2,5‐dione 20, 2H,5H‐pyrano[3,2‐c]benzo[b]pyran‐2,5‐dione 21, 2H‐1‐benzopyran‐2‐one 22 and 24, pyrido[l,2‐a]pyrimidin‐4‐one 31–34 and 39 derivatives, and N‐heteroaryl‐1H‐imidazole‐4‐carboxylates 37 and 38.
Synthesis of thiophene/phenylene co‐oligomers. III. thienyl‐capped oligophenylenes
Authors: Hotta S. 
Published: March 2009

AbstractThe author reports the synthesis of thienyl‐capped oligophenylenes via improved synthetic schemes. These schemes are based on either the Grignard or Suzuki coupling reaction and enable the author to obtain the target compounds at appreciably high yields. Regarding several of these compounds, their synthesis and characterization are believed to be reported for the first time. The resulting materials have been fully characterized through the nmr and ir spectroscopy. The ir analysis is particularly useful in characterizing the materials of higher molecular weight, since those materials are difficult to dissolve in organic solvents.
Efficient one‐pot synthesis of s‐triazolo[3,4‐b]‐[1,3,5]thiadiazines containing a chiral side chain by double mannich type reaction
Authors: Shi Haijian , Shi Haoxin , Wang Zhongyi 
Published: March 2009

AbstractAn efficient and convenience method has been developed via a one‐pot double Mannich type reaction for the synthesis of the important chiral s‐triazole derivatives: (S)‐3‐α‐phenylethyl‐2,4‐dihydro‐5‐aryl‐oxymethyl‐1,2,4‐triazolo [3,4‐b] ‐1,3,5 ‐thiadiazines.
A library of pyranocoumarin derivatives via a one‐pot three‐component hetero diels‐alder reaction
Authors: Cravotto Giancarlo , Nano Gian Mario , Tagliapietra Silvia , Palmisano Giovanni , Pilati Tullio 
Published: March 2009

AbstractA hetero Diels‐Alder reaction with inverse electron demand between 4‐hydroxycoumarin, aromatic aldehydes and electron‐rich alkenes yielded a multitude of 2,4‐disubstituted 3,4‐dihydropyranocoumarins. This route opened an easy access to coumarin anticoagulants and provided a library of pyranocoumarin derivatives.
Synthesis of 1‐methyl‐, 4‐nitro‐, 4‐amino‐and 4‐iodo‐1,2‐dihydro‐3H‐pyrazol‐3‐ones
Authors: Fiamegos Y. C. , Pilidis G. A. , Varvounis G. 
Published: March 2009

Abstract4‐Aminopyrazole‐3‐ones 4b, e, f were prepared from pyrazole‐3‐ones 1b‐d in a four‐step reaction sequence. Reaction of the latter with methyl p‐toluenesulfonate gave 1‐methylpyrazol‐3‐ones 2b‐d. Compounds 2b‐d were treated with aqueous nitric acid to give 4‐nitropyrazol‐3‐ones 3b‐d. Reduction of compounds 3b‐d by catalytic hydrogenation with Pd‐C afforded the 4‐amino compounds 4b, e, f. Using similar reaction conditions, nitropyrazole‐3‐ones derivatives 2c, d were reduced into aminopyrazole‐3‐ones 5e, f. 4‐Iodopyrazole‐3‐ones 7a, 7c and 8 were prepared from the corresponding pyrazol‐3‐ones 2a, 2c and 6 and iodine monochloride or sodium azide and iodine monochloride.
Preparation of 6‐, 7‐, and 8‐substituted derivatives of 2‐Oxa‐1,3,4,10‐tetraazacyclopenta[b]fluoren‐9‐one
Authors: Bratton Larry D. , Unangst Paul C. , Rubin J. Ronald , Trivedi Bharat K. 
Published: March 2009

AbstractThe preparation of a variety of derivatives of 2‐oxa‐1,3,4,10‐tetraazacyclopenta[b]fluoren‐9‐one 1 is described. A series of substituted indan‐1‐ones were prepared and oxidized with N‐bromosuccinimide and dimethyl sulfoxide to the corresponding ninhydrin derivatives. Cyclization of the ninhydrins with furazan‐3,4‐diamine yielded the target tetracycles. Appropiate choice of substituents in ninhydrins led to a preference for one regioisomer in the target tetracycles. This permitted the synthesis of a variety of 8‐substituted hetero‐cycles. In those instances where isomer formation was possible, structural assignments were confirmed by X‐ray crystallography.
Synthesis of pyrazolo[1,5‐a]‐, 1,2,4‐triazolo[1,5‐a]‐ and imidazo[1,2‐a]pyrimidines related to zaleplon, a new drug for the treatment of insomnia
Authors: Mustazza Carlo , Giudice Maria Rosaria Del , Borioni Anna , Gatta Franco 
Published: March 2009

AbstractThis paper describes the preparation of some pyrazolo[1,5‐a]‐, 1,2,4‐triazolo[1,5‐a]‐ and imidazo[1,2‐a]‐pyrimidines substituted on the pyrimidine moiety by a 4‐[(N‐acetyl‐N‐ethyl)amino]phenyl group. A new synthesis of related benzo[h]pyrazolo[1,5‐a]‐, benzo[h]pyrazolo[5,1‐b]‐ and benzo[h]1,2,4‐triazolo[1,5‐a]‐quinazolines is also reported.
Synthesis of regioisomeric 2,5‐bis‐substituted‐aza‐benzothiopyranoindazoles
Authors: Krapcho A. Paul , Haydar Simon N. 
Published: March 2009

AbstractThe synthesis of 6‐chloro‐9‐nitro‐benzothiopyranopyridin‐5‐ones2a, 2band2chas been accomplished. Chemotype2dcould not be prepared since attempts to cyclize 3‐(2‐nitro‐5‐chlorophenoxy)pyridine‐2‐carboxylic acid (1d) led to the decarboxylation product 3‐(2‐nitro‐5‐chlorothiophenoxy) pyridine (40). Analogues2a, 2bor2con treatment with the respectively substituted hydrazine led to the 2‐(substituted)‐5‐nitro 7, 8‐ or 9‐aza substituted chemotypes3a‐7a, 8b, and9c‐13c. The reduction of the nitro groups of these substrates was effected by treatment with hydrogen gas (palladium catalyst) or by stannous chloride to yield the 5‐amino chemotypes15a‐18a, 20band21c‐24c, respectively. The conversion of these derivatives to the 2,5‐bis (alkylamino)‐7‐, 8‐ and 9‐aza benzothiopyranoindazoles listed in Table 3 was accomplished by direct alkylations, acylations, followed by reduction of the amido group with Red‐Al or lithium aluminum hydride, or by reductive alkylations in the presence of sodium cyanoborohydride. The removal of the protective BOC‐group was effected by treatment of the appropriate substrates with anhydrous hydrogen chloride to afford the respective hydrochloride salts listed in Table 4.
Synthesis of new 2,4‐diamino‐7H‐pyrrolo[2,3‐d]pyrimidines via the Taylor ring transformation/ring annulation strategy
Authors: Rosowsky Andre , Fu Hongning , Queener Sherry F. 
Published: March 2009

AbstractSelected examples 2,4‐diamino‐7H‐pyrrolo[2,3‐d]pyrimidines with a phenyl or benzyl group at the 5‐position were synthesized as inhibitors of dihydrofolate reductase (DHFR) from Pneumocystis carinü and Toxoplasma gondii, two potentially life‐threatening opportunistic pathogens associated with AIDS and other disorders of the immune system. Aldol condensation of paraformaldehyde with substituted benzaldehydes or with phenylacetaldehyde afforded α‐hydroxyketones with a phenyl or benzyl group at the 4‐position. Further reaction of the hydroxyketones with malononitrile afforded 2‐aminofuran‐3‐carbonitriles, which upon heating with guanidine underwent ring transformation/ring annulation to produce 2,4‐diamino‐7H‐pyrrolo[2,3‐d]pyrimidines rather than 2,4‐diaminofuro[2,3‐d]pyrimidines. One of the target compounds obtained in this manner, 2,4‐diamino‐5‐(3,4,5‐trimethoxyphenyl)‐7H‐pyrrolo[2,3‐d]pyrimidine (1d), may be viewed as a conformationally restricted analogue of trimethoprim, an antimicrobial agent widely used in combination with a sulfa drug to treat P. carinii and T. gondii opportunistic infections in patients with AIDS. Compound 1d inhibited P. carinii and T. gondii DHFR with IC50 values of 8.3 and 14 μM, respectively. This potency was somewhat greater than that of trimethoprim. However, because this compound was also more potent than trimethoprim against mammalian (rat liver) DHFR rat liver it lacked species selectivity. The other 2,4‐diamino‐7H‐pyrrolo[2,3‐d]pyrimidines synthesized were neither potent nor selective.
Non‐biaryl atropisomers. part 1. configurationally stable 1,2‐diaryl‐3‐methyl‐1,4,5,6‐tetrahydropyrimidinium salts
Authors: García Maria B. , Perillo Isabel A. , Orelli Liliana R. 
Published: March 2009

AbstractIn the present communication we describe two examples of a new kind of configurationally stable non‐biaryl atropisomers in which the Ar‐N bond is the chiral axis, namely 1‐(o‐nitrophenyl)‐2‐aryl‐3‐methyl‐1,4,5,6‐tetrahydropyrimidinium iodides 1. Stereochemical features of such compounds are analyzed on the basis of their 1H and 13C one‐ and two‐dimensional nmr spectra. A comparison is made with the corresponding amidines 2.
Inverse‐electron demand [π2 + σ2 + σ2] cycloaddition reaction of dimethyl oxaquadricyclane‐2,3‐dicarboxylate with cyclooctyne
Authors: Matsumoto Kiyoshi , Taketsuna Hiroyuki , Kim Jong Chul , Kakehi Akikazu 
Published: March 2009

AbstractA first example of an inverse‐electron demand [π2 + σ2 + σ2] cycloaddition reaction of dimethyl oxaquadricyclane‐2,3‐dicarboxylate was reported: cyclooctyne underwent cycloaddition with dimethyl oxaquadricyclane‐2,3‐dicarboxylate to afford the corresponding adducts one of whose structure was confirmed by a single crystal X‐ray analysis.
Ring transformations of heterocyclic compounds. XXII. Pyrido[1,2‐a]indolium salts from 2‐methyl‐3H‐indoles by pyrylium mediated three carbon annelation
Authors: Zimmermann Thomas , Hennig Lothar 
Published: March 2009

AbstractThe synthesis of pyrido[1,2‐a]indolium perchlorates 8,11 from 2,4,6‐triarylpyrylium perchlorates 1 and 2‐methyl‐3H‐indoles 6,9 in the presence of a basic condensing agent (anhydrous sodium acetate, piperidine acetate, triethylamine/acetic acid, triethylamine) in ethanol by a 2,4‐[C3+C2N] pyrylium ring transformation is reported. Spectroscopic data of the transformation products and their mode of formation are discussed.
The influence of the size and position of the alkyl groups in alkylimidazole molecules on their acid‐base properties
Authors: Lenarcik Beniamin , Ojczenasz Piotr 
Published: March 2009

AbstractDissociation constants of HL+ acids, where L stands for 1‐alkylimidazole, 1‐alkyl‐2‐methylimidazole, 1‐alkyl‐2‐ethylimidazole, 1‐alkyl‐2‐propylimidazole, 1‐alkyl‐4‐methylimidazole and 1‐alkyl‐2‐ethyl‐4‐methylimidazole, were determined potentiometrically. For each of the homologous series of these bases, a relationship has been derived between the pKa value and the number of carbon atoms in the hydrocarbon group for (CH2)n ≤ 13. The basicity of the alkylimidazoles has been found to increase linearly with increasing carbon chain length. The slopes of straight plots of pKa = f(nCH2) have been found to increase with increasing basicity of homologous series of the alkylimidazoles.
Synthesis of the azocino[4,3‐b]indole core structure for the synthesis of strychnos alkaloids
Authors: Ergün Yavuz , Okay Gürol , Patir Süleyman 
Published: March 2009

AbstractThe synthesis of compound 12 which has a hexahydro‐1,5‐methanoazocino[4,3‐b]indole structure for the synthesis of pentacyclic strychnos type alkaloids (tubifolin and tubifolidine) is described. Many new compounds 5–12 have also been synthesized.
Furopyridines. XXXI. Birch reduction of furopyridines
Authors: Yamaguchi Seiji , Hamade Eriko , Yokoyama Hajime , Hirai Yoshiro , Shiotani Shunsaku 
Published: March 2009

AbstractBirch reduction of four furopyridines 1a‐d effected the characteristic cleavage of the furan ring, giving ethnylpyridinols 2a‐d, vinylpyridinols 3b,d, and ethylpyridinols 4a‐d, and the reduction of the furan ring, giving dihydrofuropyridine 5c,d.
Oxygen analogues of the benzodiazepine alkaloids sclerotigenin and circumdatin F
Authors: Witt F. Anette , Bergman Jan 
Published: March 2009

AbstractA new type of fused oxazepinones 9a and 9b, which are analogues of sclerotigenin and circumdatin F, were obtained in a two step synthesis from 2‐(2‐amino‐benzoylamino)‐benzoic acid or the corresponding methyl ester. Secondly a new synthesis of circumdatin F arose from this work, where 2‐(2‐propionylamino‐benzoylamino)‐benzoic acid methyl ester was used as an intermediate.
Synthesis of some symmetrically substituted compounds derived from 1,3‐bis(6‐azauracil‐1‐yl)benzene and 1,3,5‐tris(6‐azauracil‐1‐yl)benzene
Authors: Bílek Petr , Slouka Jan 
Published: March 2009

AbstractThe 3,5‐bis(5‐carboxy‐6‐azauracil‐1‐yl)aniline (7) and 1,3,5‐tris(5‐carboxy‐6‐azauracil‐1‐yl)benzene (10) were prepared from 3‐amino‐5‐nitroacetanilide (1) via intermediates 2–6. A series of other substituted 6‐azauracil derivatives 9, 11‐14 were also prepared.