bluuebunny/crossref_metadata_2025 huggingface dataset:
The dependence on gp130 cytokines of axotomy induced neuropeptide expression in adult sympathetic neurons
Authors: Habecker Beth A. , Sachs Hilary Hyatt , Rohrer Hermann , Zigmond Richard E.
Published: March 2009

Adult peripheral neurons exhibit dramatic changes in gene expression after axonal injury, including changes in neuropeptide phenotype. For example, sympathetic neurons in the superior cervical ganglion (SCG) begin to express vasoactive intestinal peptide (VIP), galanin, pituitary adenylate cyclase activating polypeptide (PACAP), and cholecystokinin after axotomy. Before these changes, nonneuronal cells in the SCG begin to express leukemia inhibitory factor (LIF). When the effects of axotomy were compared in LIF−/− and wild‐type mice, the increases in VIP and galanin expression were less in the former, though significant increases still occurred. LIF belongs to a family of cytokines with overlapping physiological effects and multimeric receptors containing the subunit gp130. Real‐time PCR revealed large increases in the SCG after axotomy in mRNA for three members of this cytokine family, interleukin (IL)‐6, IL‐11, and LIF, with modest increases in oncostatin M, no changes in ciliary neurotrophic factor, and decreases in cardiotrophin‐1. To explore the role of these cytokines, animals with selective elimination of the gp130 receptor in noradrenergic neurons were studied. No significant changes in mRNA levels for VIP, galanin, and PACAP were seen in axotomized ganglia from these mutant mice, while the increase in cholecystokinin was as large as that seen in wild‐type mice. The data indicate that the inductions of VIP, galanin, and PACAP after axotomy are completely dependent on gp130 cytokines and that a second cytokine, in addition to LIF, is involved. The increase in cholecystokinin after axotomy, however, does not require the action of these cytokines. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2009
Electrical signals polarize neuronal organelles, direct neuron migration, and orient cell division
Authors: Yao Li , McCaig Colin D. , Zhao Min
Published: March 2009

During early brain development, the axis of division of neuronal precursor cells is regulated tightly and can determine whether neurons remain in the germinal layers or migrate away. Directed neuronal migration depends on the establishment of cell polarity, and cells are polarized dynamically in response to extracellular signals. Endogenous electric fields (EFs) orient cell division and direct migration of a variety of cell types. Here, we show that cell division of cultured hippocampal cells (neuron‐like cells and glial‐like cells) is oriented strikingly by an applied EF, which also directs neuronal migration. Directed migration involves polarization of the leading neurite, of the microtubule‐associated protein MAP‐2 and of the Golgi apparatus and the centrosome, all of which reposition asymmetrically to face the cathode. Pharmacological inhibition of Rho‐associated coiled‐coil forming protein kinases (ROCK) and phosphoinositide 3‐kinase decreased, leading neurite orientation and Golgi polarization in the neurons in response to an EF and in parallel decreased the directedness of EF‐guided neuronal migration. This work demonstrates that the axis of hippocampal cell division, the establishment of neuronal polarity, the polarization of intracellular structures, and the direction of neuronal migration are all regulated by an extracellular electrical cue. © 2009 Wiley‐Liss, Inc.
Diosgenin targets Akt‐mediated prosurvival signaling in human breast cancer cells
Authors: Srinivasan Sowmyalakshmi , Koduru Srinivas , Kumar Raj , Venguswamy Guhan , Kyprianou Natasha , Damodaran Chendil
Published: March 2009

In recent years, Akt signaling has gained recognition for its functional role in more aggressive, therapy‐resistant malignancies. As it is frequently constitutively active in cancer cells, several drugs are being investigated for their ability to inhibit Akt signaling. The purpose of this study is to determine effect of diosgenin (fenugreek), a dietary compound on Akt signaling and its downstream targets on estrogen receptor positive (ER+) and estrogen receptor negative (ER−) breast cancer (BCa) cells. Diosgenin inhibits pAkt expression and Akt kinase activity without affecting PI3 kinase levels, resulting in the inhibition of its downstream targets, NF‐κB, Bcl‐2, survivin and XIAP. The Raf/MEK/ERK pathway, another functional downstream target of Akt, was inhibited by diosgenin in ER+ but not in ER− BCa cells. Additionally, we found that diosgenin caused G1 cell cycle arrest by downregulating cyclin D1, cdk‐2 and cdk‐4 expression in both ER+ and ER− BCa cells resulting in the inhibition of cell proliferation and induction of apoptosis. Interestingly, no significant toxicity was seen in the normal breast epithelial cells (MCF‐10A) following treatment with diosgenin. Additionally, in vivo tumor studies indicate diosgenin significantly inhibits tumor growth in both MCF‐7 and MDA‐231 xenografts in nude mice. Thus, these results suggest that diosgenin might prove to be a potential chemotherapeutic agent for the treatment of BCa. © 2009 UICC
Reactions of furocoumarins. II. Synthetic aminomethyl psoralens via chloromethylation or benzylic bromination
Authors: Kaufman Kurt D. , Erb Dennis J. , Blok Thomas M. , Carlson Robert W. , Knoechel Donald J. , Mcbride Lincoln , Zeitlow Thomas
Published: March 2009

Several psoralen derivatives have been synthesized in order to evaluate their efficacy as photochemotherapeutic (PUVA) agents, including a variety of 4′‐substituted‐4,5′,8‐trimethypsoralen compounds (1d‐j). Improved synthesis of the very potent photosensitizers 8‐methylpsoralen (6a) and 4,8‐dimethylpsoralen (6b) are described and 6a has been shown to undergo formylation in the 4′‐position. Free radical bromination of 6a and 6b with NBS affords primarily 8‐bromomethyl derivatives (8a and d), which are readily converted into the 8‐aminomethyl derivatives (8c and f) by the Gabriel method. If the 4′‐position is blocked, electrophilic substitution apparently occurs primarily in the 5′‐position of the psoralen system. At least, chloromethylation of 4′‐methylpsoralen (9) affords mainly 5′‐chloromethyl derivatives (10a and d), which also lead to aminomethylpsoralens (10c and f).
Pyranopyrazoles. II. Synthesis and reactions of 1H,6H‐pyrano[2,3‐c]pyrazol‐6‐ones
Authors: Khan Misbahul Ain , Cosenza Alina Guerra , Ellis Gwynn Pennant
Published: March 2009

Various 1H,6H‐pyrano[2,3‐c]pyrazol‐6‐ones (III‐XXIII) were obtained from β‐keto esters and 1H‐pyrazol‐5‐ones or hydrazines. Nitrations, chlorinations and brominations of these pyranopyrazoles were also carried out giving the corresponding derivatives (XXIV‐LXIV). The pyrone ring is the more reactive one in these reactions and the preferred position of attack is the 5‐position. The substitution products are formed by the addition‐elimination route.
Synthesis of 2‐substituted isothiazolopyridin‐3‐ones
Authors: Baggaley Keith H. , Jennings L. John A. , Tyrrell A. William R.
Published: March 2009

The synthesis of some 2‐substituted derivatives 1–4 of all four isomeric isothiazolopyridin‐3‐ones is described. Several novel 1,2‐dithiolopyridin‐3‐ones and 3‐thiones were prepared as intermediates.
The substitution reaction of pyrazine‐2,3‐dicarbonitrile derivatives with ammonia, amines, water and alcohols
Authors: Hirano Hideki , Lee Rachel , Tada Masaru
Published: March 2009

5‐Arylpyrazine‐2,3‐dicarbonitriles 1 and 2 give 2‐alkylamino‐5‐arylpyrazine‐3‐carbonitriles 3 and 5 and 3‐alkylamiono‐5‐arylpyrazine‐2‐carbonitriles 4 and 6 by the substitution reaction with amines but give only 3‐aminopyrazine‐2‐carbonitrile derivative on the reaction with ammonia. The reaction of 5‐arylpyrazine‐2,3‐dicarbonitriles (1 and 2) with alcohols in the presence of a base gives 2‐alkoxypyrazine‐3‐carbonitrile derivatives 9 and 13 and 3‐alkoxypyrazine‐2‐carbonitrile derivatives 10 and 14. The reaction of water gives two pyrazinonecarbonitrile derivatives 11 and 12. In these reactions the aryl groups on the pyrazine ring are 3,4‐dimethoxyphenyl and benzo‐15‐crown‐5.
1,2,4‐triazines. III. A convenient and general synthesis of 4H‐[1,3,4]thiadiazolo[2,3‐c][1,2,4]triazin‐4‐ones
Authors: Mizutani Masato , Sanemitsu Yuzuru
Published: March 2009

4H‐[1,3,4]Thiadiazolo[2,3‐c][1,2,4]triazin‐4‐ones were prepared by cyclization of 3‐thio‐4‐amino‐1,2,4‐tri‐azine‐3,5(2H,4H)‐diones with a variety of acids in the presence of concentrated sulfuric acid. The synthesis appears to be general.
Nitrogen bridgehead compounds, Part 311H and 13C NMR study of tetra‐ and octahydro‐11H‐pyrido[2,1‐b]quinazolin‐11‐ones
Authors: Hermecz István , Podányi Benjamin , Mészáros Zoltán , Kökösi József , Szász György , Tóth Gábor
Published: March 2009

Conformational analysis of some tetra‐and octahydro‐11H‐pyrido[2,1‐b]quinazolin‐11‐ones 1‐3 by 1H and 13C nmr revealed that the 9‐methyl‐6,7,8,9‐tetrahydro derivative exists mainly in the conformation containing the methyl group in a quasi‐axial orientation. Of the 1,2,3,4,5,6,7,8‐octahydro compounds, the 9‐methyl derivative 3e contains the methyl group in a quasi‐axial position, while that in the 7‐methyl and the 8‐methyl derivatives 3c,d is in the equatorial position, and the 6‐methyl derivative 3b is a mixture of the two conformers.
The synthesis of 3,5‐dimethylpyrazol‐1‐yl‐vl‐v‐triazolo[4,5‐d]pyridazines and substituted 3,5‐dimethylpyrazol‐1 ‐ylimidazo[4,5‐d]pyridazines
Authors: Draper Randall E. , Castle Raymond N.
Published: March 2009

The synthesis of 4‐(3,5‐dimethylpyrazol‐1‐yl)‐v‐triazolo[4,5‐d]pyridazine, 4‐(3,5‐dimethylpyrazol‐1‐yl)imid‐azo[4,5‐d]pyridazine and several S‐substituted derivatives of 4‐(3,5‐dimethylpyrazol‐1‐yl)imidazo[4,5‐d]pyrid‐azine‐2‐thiol is reported. These syntheses were carried out to provide a variety of interesting compounds for biological screening.
Synthesis of crown‐ether precocenes
Authors: Camps F. , Coll J. , Ricart S.
Published: March 2009

Preparation of potential insect antijuvenile hormone agents with 15‐crown‐5 and 18‐crown‐6 moieties connecting the C‐6 and C‐7 positions of the 2 H‐chromene ring of precocenes is described.
1H‐pyrazolo[3,4‐d]thieno[2,3‐b]pyridine and its derivatives
Authors: Khan Misbahul Ain , Rolim Alice Maria Coimbra , Guarçoni Antonio Elydio
Published: March 2009

The synthesis of the parent ring system and some of the derivatives of 1H‐pyrazolo[3,4‐d]thieno[2,3‐b]pyridine are described.
An efficient synthesis of trans‐hexahydrochroman‐7‐one
Authors: Forchiassin M. , Russo C.
Published: March 2009

The title compound is obtained in good yield from 4‐(2‐carboxyethyl)resorcinol (1) by a simplified synthesis.
Oxidation of bis‐aroylhydrazones of 3,3‐dimethylpentane‐2,4‐dione and thermal decomposition of the oxidation products
Authors: Stephanidou‐Stephanatou J.
Published: March 2009

Oxidation of the title bis‐aroylhydrazones 2 with lead tetraacetate gives l‐aroyl‐5‐aroylazo‐3, 4, 4, 5‐tetramethyl‐2‐pyrazolines 6 in good yields. The aroylazopyrazolines 6 decompose by refluxing in chloroform or ethanol solution to l‐aroyl‐5‐hydroxy‐3, 4, 4, 5‐tetramethyl‐2‐pyrazolines 3, l‐aroyl‐5‐methylene‐3, 4, 4‐trimethyl‐2‐pyrazoles 10 and 1‐aroyl‐3, 4, 4, 5‐tetramethyl‐2‐pyrazolines 11. The spectral data of the prepared compounds, as well as the reaction mechanisms are discussed.
Potential cerebral perfusion agents. Synthesis and evaluation of new radioiodinated barbituric acid analogs
Authors: Srivastava Prem C. , Guyer Clarence E. , Knapp Furn F.
Published: March 2009

Two new 125I‐labeled barbituric acid analogs, 5‐ethyl‐5‐(E‐1‐iodo‐1‐penten‐5‐yl)2‐thiobarbituric acid (4) and 5‐ethyl‐5‐(m‐iodophenyl)barbituric acid (7), have been prepared and evaluated in rats as potential cerebral perfusion agents. Annulation of 2‐ethyl‐2‐(E‐1‐iodo‐1‐penten‐5‐yl)malonate (3) with thiourea in the presence of sodium ethoxide gave the 5‐ethyl‐5‐(E‐1‐iodo‐1‐penten‐5‐y1)‐thiobarbituric acid (4). Diethyl 2‐ethyl‐2‐phenyl‐malonate was treated with thallium(III) trifluoroacetate followed by addition of aqueous potassium iodide to provide diethyl 2‐ethyl‐2‐(m‐iodophenyl)malonate (10). The malonic ester derivative 10 was condensed with urea in the presence of sodium hydride to give the desired 5‐ethyl‐5‐(m‐iodophenyl)barbituric acid (7), and a decarbethoxylation product, 2‐(m‐iodophenyl)butyric acid (11). Iodine‐125‐labeled 4 and 7 were synthesized in the same manner and the tissue distribution of these new agents evaluated in rats. Both [125I] 4 and [125I] 7 showed high brain uptake. Significant in vivo deiodination was detected with [125I] 4 whereas [125I] 7 was found to be stable to deiodination.
Strained heterocyclic systems. 11. Crystal and molecular structure of 1,2‐dihydrocyclobuta[b]quinoline
Authors: Deroski Betty R. , Markgraf J. Hodge , Ricci John S.
Published: March 2009

The structure of the title compound (1) has been elucidated by an X‐ray crystal determination. The crystals are triclinic, space group PI with a unit cell of dimensions a = 6.6109(5), b = 7.5939(4), c = 9.3171(6), α = 77.133(5), β = 75.566(6), γ = 63.575(5). The model was refined to an R value (unweighted) of 4.3% for 1551 independent reflections. The distortion of the heterocyclic ring, with a CNC bond angle of 112.5,° is in accordance with a prior calculation and relates to the observed reduction in basicity.
Regioselective arylation of 3‐bromopyridine
Authors: Comins Daniel L. , Mantlo Nathan B.
Published: March 2009

The addition of aryl Grignard reagents to the 1‐phenoxycarbonyl salt of 3‐bromopyridine affords 2‐aryl‐5‐bromo‐1‐phenoxycarbonyl‐1,2‐dihydropyridines and 4‐aryl‐3‐bromo‐1‐phenoxycarbonyl‐1,4‐dihydropyridines. The crude dihydropyridines were aromatized with o‐chloranil in refluxing toluene to give 4‐ and 6‐aryl‐3‐bromopyridines. The regioselectivity of this two‐step process, 6‐ vs. 4‐substitution, was examined and found to be dependent upon the structure of the Grignard reagent. Unhindered aryl Grignard reagents, e.g., phenyl and 2‐naphthyl, gave mainly 6‐aryl‐3‐bromopyridines (49‐52%) along with 9% of the 4‐substituted isomer and less than 4% of the 2‐aryl‐3‐bromopyridine. Hindered aryl Grignard reagents, e.g., o‐tolyl and 1‐naphthyl, are less regioselective. When a catalytic amount of cuprous iodide is present during the Grignard reaction, nearly exclusive 1,4‐addition results. The crude 4‐aryl‐3‐bromo‐1,4‐dihydropyridines were aromatized with p‐chloranil to provide 4‐aryl‐3‐bromopyridines in good yield and high isomeric purity. The sequential use of the cuprous iodide‐catalyzed Grignard reaction and the “normal” Grignard reaction provided a regiospeci‐fic synthesis of 3‐bromo‐6‐(p‐methoxyphenyl)‐4‐phenylpyridine from 3‐bromopyridine.
Functionalization of substituted 2(1H)‐ and 4(1H)‐pyridones. III. The preparation of substituted 6‐Vinyl‐1,2‐dihydro‐2‐oxo‐ and 1,4‐dihydro‐4‐oxo‐3‐pyridinecarboxylic acids through the chemistry of pyridone dianions
Authors: Dejohn Dana , Domagala John M. , Kaltenbronn James S. , Krolls Uldis
Published: March 2009

The synthesis of various substituted 6‐vinyl‐1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxylic acids from the dianions of 1,2‐dihydro‐6‐methyl‐2‐oxo‐3‐pyridinecarbonitrile and the corresponding 3‐t‐butyl ester is reported. The dianions were generated with LDA in THF at low temperature and reacted with various carbonyl substrates. Several conditions for the dehydration and hydrolysis of these adducts to the vinyl pyridone acids are discussed. Employing the conditions used for the 2‐pyridone analogs, a series of substituted 6‐vinyl‐1,4‐di‐hydro‐4‐oxo‐3‐pyridinecarboxylic acids was prepared through the new dianion of 1,4‐dihydro‐6‐methyl‐4‐oxo‐3‐pyridinecarboxylic acid, t‐butyl ester.
1,4‐benzothiazine derivatives from 2‐aminobenzenethiol and hydrazonoyl halides
Authors: Almirante Nicoletta , Forti Luciana
Published: March 2009

2‐Aminobenzenethiol was condensed with alkyl α‐chlorophenylhydrazonoglyoxylates yielding alkyl 2‐(2‐aminophenylthio)‐2‐arylhydrazonoglyoxylates which were cyclized to the corresponding 2‐arylhydrazono‐2,3‐dihydro‐4H‐1,4‐benzothiazin‐3‐ones. Starting from α‐chloro‐α‐arylhydrazonoacetones the corresponding 2‐arylhydrazono‐3‐methylbenzo‐1,4‐benzothiazines were formed.
Mass Spectral Fragmentation Patterns of 11‐(o‐ and p‐R‐Anilino)‐5H‐dibenzo[b,e][1,4]diazepines. IV
Authors: Cortés E. , Martínez R. , Zarza A.
Published: March 2009

The mass spectral fragmentation patterns of eleven 11‐(o‐ and p‐R‐anilino)‐5H‐dibenzo[b,e][1,4]diazepines obtained by electron impact have been studied. All the spectra analyzed contain molecular ions, which are base peak for para isomers and the principal fragmentation routes takes place either from the molecular ion, or from (M+ ‐ 1) ion. There are, however, some deviations from the general fragmentation pattern in the case of 1,4‐dibenzodiazepines with o‐amino and p‐methoxy substituents caused by direct interaction of these groups with the dibenzodiazepine ring.
A facile synthesis of two thioacrolein dimers. A new entry to a flavor component in asparagus
Authors: Beslin Pierre
Published: March 2009

A simple synthesis of 3,4‐dihydro‐3 vinyl‐1,2‐dithiin (2) and 2‐vinyl‐4H‐1,3 dithiin (3) is reported.
Pyrrolothiénopyrazines: Etude chimique de la pyrrolo[1,2‐a]thiéno[2,3‐e]pyrazine
Authors: Effi Yamien , Lancelot Jean‐Charles , Rault Sylvain , Robba Max
Published: March 2009

La réactivité de la pyrrolo[1,2‐a]thiéno[2,3‐e]pyrazine 1 est étudiée vis à vis des réactions de quaternarisation, bromation, nitration, Friedel‐Crafts, Vilsmeier‐Haack et de Reissert. La structure des produits obtenus est déduite de l'analyse de leur spectre de rmn ou de masse ou par synthèse univoque.
A synthesis of 2‐β‐D‐ribofuranosyl‐4‐selenazolecarboxamide (selenazofurin) and certain N‐substituted amide derivatives suitable for large scale syntheses
Authors: Dan Cook P. , Mcnamara Dennis J.
Published: March 2009

A new process suitable for large scale synthesis of the antitumor‐antiviral agent, 2‐β‐D‐ribofuranosyl‐4‐selenazolecarboxamide (selenazofurin, 1), has been developed. Thus, 1‐O‐acetyl‐2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranose (3) was converted with cyanotrimethylsilane and stannic chloride to the crystalline 2,5‐anhydro‐3,4,6‐tri‐O‐benzoyl‐β‐D‐allononitrile (4) without chromatography. Cyanosugar 4 in ethanol was treated with hydrogen selenide gas to afford stereospecifically the unstable 2,5‐anhydro‐3,4,6‐tri‐O‐benzoyl‐β‐D‐allonoselenoamide (5) which was converted in situ by ethyl bromopyruvate to the stable ethyl 2‐(2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranosyl)‐4‐selenazolecarboxylate (6). Selenazole ethyl ester 6 was deprotected with sodium methoxide affording methyl 2‐β‐D‐ribofuranosyl‐4‐selenazolecarboxylate (7) which was aminated with ammonia to provide selenazofurin (1) or with other amines to provide N‐substituted selenazofurin amides.
Synthesis of [1]benzothieno[2,3‐e]pyrrolo[1,2a]pyrazines and related compounds
Authors: El‐Kashef Hussein , Rault Sylvain , Lancelot Jean‐Charles , Robba Max
Published: March 2009

The synthesis of several [1]benzothieno[2,3‐e]pyrrolo[1,2‐a]pyrazines and other related heterocycles has been described. A study of the nmr spectra of these compounds was also reported.
Synthesis of 7‐substituted imidazo[1,2‐a]pyrimidin‐5(1H)‐ones
Authors: Nugent Richard A. , Murphy Megan
Published: March 2009

The synthesis of 7‐substituted imidazo[1,2‐a]pyrimidin‐5(1H)‐ones by either of 2 methods is reported.
Purine acyclic nucleosides. Unambiguous synthesis of acyclovir via a furazano[3,4‐d]pyrimidine
Authors: Kelley James L. , Schaeffer Howard J.
Published: March 2009

Acyclovir was synthesized in five steps from 7‐formamido‐5‐methylthiofurazano[3,4‐d]pyrimidine 2. Alkylation of 2 with 2‐(benzoyloxy)ethoxymethyl chloride, followed by reductive cleavage of the furazan ring gave 9‐[[2‐(benzoyloxy)ethoxy]methyl]‐2‐(methylthio)adenine 5. Hydrolysis of the 6‐amino group of 5, followed by amination of 7 with ammonia gave 9‐[(2‐hydroxyethoxy)methyl]guanine (1, acyclovir).
Facile synthesis of fluorine‐containing [4‐aryl‐4,5‐dihydro‐5‐imino‐1,3,4‐thiadiazol‐2‐ylaryl]methanone, 2‐amino‐4‐aryl‐5‐arylazothiazoles and 3‐aroyl‐4‐acetyl/benzoyl‐5‐methyl‐1‐phenylpyrazoles through N‐aryl‐α‐oxo‐α‐arylethanehydrazonoyl bromide
Authors: Joshi Krishna C. , Pathak Vijai N. , Sharma Sharda
Published: March 2009

N‐Aryl‐α‐oxo‐α‐arylethanehydrazonoyl bromides 2 react with potassium thiocyanate in ethanol leading to the formation of [4‐aryl‐4,5‐dihydro‐5‐imino‐1,3,4‐thiadiazol‐2‐ylaryl]methanone 5 in quantitative yield. Treatment of 2 with thiourea and β‐diketones affords 2‐amino‐4‐aryl‐5‐arylazothiazoles 4 and 3‐aroyl‐4‐acetyl/benzoyl‐5‐methyl‐1‐phenylpyrazoles 6 in 65–70 and 60–70% yields respectively. Compound 5 has also been subjected to acetylation and chloroacetylation. All the compounds are characterized by their analytical and spectral (ir, 1H‐nmr and ms) data. Mass fragmentation patterns of these compounds are discussed.
The synthesis of benzofuroquinolines. V. Some benzofuro[3,2‐B]quinoline derivatives
Authors: Yamaguchi Seiji , Tsuzuki Kunihiro , Sannomiya Yoshie , Oh‐Hira Yutaka , Kawase Yoshiyuki
Published: March 2009

Some benzofuro[3,2‐b]quinoline derivatives 1a‐d and 3a were synthesized by condensation of 2‐amino‐benzaldehyde, 2‐aminoacetophenone, 2‐aminobenzophenone, isatin, or 2‐aminobenzoic acid with 3(2H)‐benzofuranone. The benzofuroquinolinone 3a was also obtained from 2‐aminobenzoic acid and phenoxy‐acetyl chloride in two steps and converted to 10‐chloro derivative 1e. Similarly, some 8‐halobenzofuro[3,2‐b]‐quinoline derivatives 1d,e and 3a (X = F, Cl, Br, I) were synthesized from 5‐haloisatin or 2‐amino‐5‐halo‐benzoic acid. And benzofuro[3,2‐b]quinolines 1a‐e thus obtained were converted to corresponding N‐oxides 2.
Aminophenyl‐X‐azolopyridines as precursors of heterocyclic azo dyes
Authors: Savarino P. , Viscardi G. , Carpignano R. , Borda A. , Barni E.
Published: March 2009

Aminophenyl‐X‐azolopyridines (X = O, S, NH) are interesting intermediates for the synthesis of disperse azo dyes and, provided the pyridine nitrogen is quaternized, of their cationic counterparts. A set of novel amines and nitro derivatives is described, and their physical properties and spectral parameters are discussed in comparison with those of analogous compounds. Some dyes in the oxazole series function as probes of the reactivity of the pentatomic ring.
Enzymatic ADP‐ribosylation of benzotriazoles and related triazoles. Difference of glycosidation site between triazoles and indazoles
Authors: Tono‐Oka Shuichi , Azuma Ichiro
Published: March 2009

Some benzotriazoles and related triazole were ADP‐ribosylated in the presence of NAD and NAD‐nucleo‐sidase to give corresponding dinucleotides. The site of ribosylation for these dinucleotides was found exclusively to be N‐1 on the basis of their uv and 15N‐nmr spectra, contrasting with N‐2 for indazole dinucleotides. The origin of this difference in regiochemical specificity between the triazole and diazole systems is discussed.
Furan derivatives. Part 10. Synthesis of cyclohepta[cd]benzofuran
Authors: Horaguchi Takaaki , Hasegawa Eietsu , Shimizu Takahachi , Tanemura Kiyoshi , Suzuki Tsuneo
Published: March 2009

Cyclohepta[cd]benzofuran 2 was synthesized by heating (5‐oxo‐5H‐benzocyclohepten‐4‐yloxy)acetic acid 16 with sodium acetate in acetic anhydride or by photocyclization of 16 in acetonitrile. Several reactions of cyclohepta[cd]benzofuran 2 were examined. Protonation of 2 with trifluoroacetic acid occurred at the 2‐position to give a tropylium ion 17. Catalytic hydrogenation of 2 with palladium on charcoal proceeded smoothly to give tetrahydrocyclohepta[cd]benzofuran 18. The Diels‐Alder reaction of 2 with tetracyano‐ethylene produced an adduct 19. Formylation of 2 with phosphorus oxychloride and dimethylformamide occurred easily at the 2‐position to afford compound 20. Cyclohepta[cd]benzofuran 2 has both properties of heptafulvene and benzofuran.
Synthesis and reactions of halo‐, nitro‐, and arylazo‐substituted 3‐cinnamoyltropolones. Formation of styryl‐substituted heterocycle‐fused troponoid compounds
Authors: Gao Wen‐Tao , Jin Zhong‐Tian , Yin Bing‐Zhu , Imafuku Kimiaki
Published: March 2009

3‐Cinnamoyltropolone (1) reacted with bromine to afford 7‐bromo‐ (2), 5,7‐dibromo‐3‐cinnamoyltropolone (3), and 6,8‐dibromo‐4,9‐dihydrocyclohepta[b]pyrane‐4,9‐dione (4) according to amount of the reagent. Iodination and nitration of 1 gave respectively 7‐iodo‐ (5) and 5‐nitro‐3‐cinnamoyltropolone (6). Azo‐coupling reactions gave 5‐arylazo‐3‐cinnamoyltropolones 7a‐f. Compounds 1, 2, 3 and 5 reacted with hydroxylamine to give 3‐styryl‐8H‐cyclohept[d]isoxazol‐8‐ones 10‐13, while 6 and 7a gave 5‐nitro‐3‐styryl‐8H‐cyclohept[d]‐isoxazol‐8‐one oxime (14) and 2‐cinnamoyl‐7‐methoxy‐4‐phenylazotropone (15), respectively. The reactions of 1,3, and 5 with phenylhydrazine gave 3‐styryl‐1,8‐dihydrocycloheptapyrazol‐8‐ones 16‐19.
Chemotherapeutic agents. IX. Synthesis and pesticidal activities of bis[4‐aryl/alkyl‐1, 2, 4‐triazoline‐5‐thione‐3‐yl]alkanes and 1 ‐Aryl/alkyl‐3‐[4‐(4‐aryl/alkyl‐1, 2, 4‐triazoline‐5‐thione‐3‐yl)phenyl]thiourea and related compounds
Authors: Ram Vishnu J. , Dube Vidyottama , Pieters Luc A. C. , Vlietinck Arnold J.
Published: March 2009

Various bis[4‐aryl/alkyl‐1, 2, 4‐triazoline‐5‐thione‐3‐yl]alkanes (3) were prepared from base cyclization of bis thiosemicarbazide 2 and transformed into sulphides by reaction with different alkyl halides in alkaline medium. These compounds were further oxidised to sulphones 5 with acidic potassium permanganate. 1‐Aryl‐3‐[4‐(4‐aryl/alkyl‐1, 2, 4‐triazoline‐3‐thione‐5‐yl)phenyl]thioureas (8) were prepared in two steps from p‐aminophenylhydrazide (6) and aryl/alkylisothiocyanates. Alkylation of 8 with different alkyl halides yielded exclusively sulphides 9. Some sulphides 12 and Mannich bases 13 from 5‐(p‐fluorophenyl)‐1, 3, 4‐oxadiazol‐2‐thione (11) were also prepared to evaluate their pesticidal activities. All the prepared compounds were screened for pesticidal activities but none of them exhibited any significant activity.
Synthesis of 1, 5‐ and 1, 7‐dichloro‐9H‐thioxanthen‐9‐ones
Authors: Okabayashi Ichizo , Murakami (Née Iwata) Noriko , Sekiya Kaoru
Published: March 2009

1, 5‐Dichloro‐9H‐thioxanthen‐9‐one (2) was prepared by cyclization of 2‐chloro‐6‐[(2‐chlorophenyl)thio]‐benzoic acid (10) obtained from 2‐chloro‐6‐iodobenzoic acid (9) and 2‐chlorobenzenethiol. Similarly, 1, 7‐di‐chloro‐9H‐thioxanthen‐9‐one (6) was prepared from 9 via 2‐chloro‐6‐[(4‐chlorophenyl)thio]benzoic acid (11). Compound 6 was also obtained by condensation of 2‐chloro‐6‐mercaptobenzoic acid (12) with chlorobenzene in the presence of sulfuric acid.
Synthèse et étude structurale d'alcoxy‐8 et hydroxy‐8 [1, 2, 4]triazolo[4, 3‐c] et [1, 5‐c]pyrimidines
Authors: Sliwa H. , Blondeau D. , Rousseaux O.
Published: March 2009

Les alcoxy‐8 [1, 2, 4]triazolo[4, 3‐c] et [1, 5‐c]pyrimidines ont été obtenues par condensation d'une alcoxy‐5 hy‐drazino‐4 pyrimidine avec l'orthoformiate d'éthyle. L'utilisation d'orthoacétate d'éthyle conduit aux dérivés correspondants méthylés au niveau du cycle triazole. Les nouveaux phénols hétérocycliques hydroxy‐8 [1, 2, 4]triazolo[4, 3‐c] et [1, 5‐c]pyrimidines ont été préparés par hydrogénolyse des éthers benzyliques correspondants.
Synthesis of substituted tetrahydropyrimido‐[4, 5‐b][1, 7]naphthyridines as potential antitumor agents
Authors: Gangjee Aleem , Donkor Isaac O.
Published: March 2009

The synthesis of two linear trisubstituted 6, 7, 8, 9‐tetrahydropyrimido[4, 5‐b][1, 7]naphthyridines 1 and 3 were accomplished by the regiospecific cyclocondensation of two disubstituted 6‐aminopyrimidines 10 and 11 with the ketoaldehyde 1‐benzyl‐4‐hydroxymethylene‐3‐piperidone. Catalytic debenzylation of 1 afforded the disubstituted compound 2. The linear structures of 1–3 were established by 1H nmr and 13C nmr.
Selenium heterocycles. XXXIX. Synthesis of thieno[3, 4‐d]thiazole, thieno[3, 4‐d]selenazole, selenolo[3, 4‐d]thiazole and selenolo[3, 4‐d]selenazole
Authors: Shafiee A. , Shafaati A. , Habibi‐Khameneh B.
Published: March 2009

Starting from readily available methyl 2‐substituted4‐methyl‐5‐thiazolyl ketone and methyl 4‐methyl‐2‐phenyl‐5‐selenazolyl ketone, thieno[3, 4‐d]thiazole, thieno[3, 4‐d]selenazole, selenolo[3, 4‐d]thiazole and selenolo[3, 4‐d]selenazole were prepared. The structures of all compounds were confirmed by analytical and spectroscopic methods.
Research on nitrogen containing heterocyclic compounds. XVI. Synthesis of 1, 3, 4, 14b‐tetrahydro‐2, 10‐dimethyl‐2H,10H‐pyrazino[2, 1‐d]pyrrolo[1, 2‐b][1, 2, 5]benzotriazepine (1:1) maleate (10‐methyl‐10‐azaaptazepine)
Authors: Stefancich Giorgio , Silvestri Romano
Published: March 2009

A synthesis of the potential antidepressant 1, 3, 4, 14b‐tetrahydro‐2, 10‐ditnethyl‐2H,10H‐pyrazino[2, 1‐d]‐pyrrolo[1, 2‐b][1, 2, 5]benzotriazepine 4, structurally related to aptazepine, is reported in four steps. The key steps of the synthesis were the formation of the tricyclic compound ethyl 10, 11‐dihydro‐5‐methyl‐5H‐pyrrolo[1, 2‐6‐b][1, 2, 5]benzotriazepine‐11‐carboxylate 6 via a Pictet‐Spengler type condensation and the formation of the diketopiperazine 8 by cyclization of the chloroester 7 with methylamine.
Substitutions by nucleophilic free radicals: A new general reaction of heteroaromatic bases
Authors: Minisci Francesco , Fontana Francesca , Vismara Elena
Published: March 2009

The substitution of protonated heteroaromatic bases by nucleophilic carbon‐centered radicals has been developed as one of the most general reactions in the heterocyclic series; its great interest results from the fact that it reproduces most of the numerous aspects of the Friedel‐Crafts aromatic substitution, but with opposite reactivity and selectivity. The most recent developments, concerning the generation of free radicals by iodine and hydrogen abstraction and decarboxylation of carboxylic acids are particularly discussed. Some processes of high synthetic value were designed on the basis of the kinetic and thermodynamic features of all the elementary steps involved in complex but selective chain processes. New general procedures for the monosubstitution in the homolytic alkylation and acylation are reported and discussed.
A facile synthesis of methyl 2‐substituted‐4‐benzoxazolecarboxylates
Authors: Goldstein Steven W. , Dambek Paul J.
Published: March 2009

Methyl 2‐substituted‐4‐benzoxazolecarboxylates were synthesized from methyl 2‐amino‐3‐hydroxybenzoate and the corresponding acid chloride or ortho acetal with pyridinium p‐toluenesulfonate as an acid catalyst. Decomposition due to hydration at the 2‐position was seen for some compounds during purification.
Reaction of N‐(4‐Pyridylrnethyl)benzamide N‐oxides and N‐[(α‐acetoxy)‐4‐pyridylmethyl]benzamides with 1,3‐diphenyl‐1,3‐propanedione
Authors: Braña Miguel F. , López Rodríguez María L. , Castellano José M. , Fernández Purificación , Garrido‐Pertierra Amando
Published: March 2009

Reaction of N‐(4‐pyridylmethyl)benzamide N‐oxides 2 with 1,3‐diphenyl‐1,3‐propanedione in the presence of acetic anhydride afforded 1,1‐dibenzoyl‐2‐(4‐pyridyl)‐2‐(benzoylamino)ethanes 4 in low yield. Treatment of N‐[(α‐acetoxy)4‐pyridylmethyl]benzamides 3 with 1,3‐diphenyl‐1,3‐propanedione in the presence of triethylamine and chloroform as a solvent provided 4 in high yield. Reaction of 4 with nucleophiles as hydrazine, methyl and phenylhydrazine gave the corresponding pyrazoles 5.
The reaction of 2‐ethoxycarbonyl‐3‐isothiocyanatopyridine with α‐amino acids. The synthesis of 3‐substituted 2‐thiooxo‐2,3‐dihydropyrido[3,2‐d]pyrimidin‐4(3H)‐ones
Authors: Urleb UroŠ , Stanovnik Branko , Tišler Miha
Published: March 2009

2‐Ethoxycarbonyl‐3‐isothiocyanatopyridine (1) reacts with α‐amino acids 2–11 and β‐alanine (12) to give pyrido[3,2‐d]pyrimidine derivatives 13–23 with the nitrogen of the amino acid component being incorporated into the fused pyrimidine ring at position 3. Methylation of 14 and 15 with DMFDMA produces S‐methylated products 24 and 25, while in the reaction of 14 with hydrazine the corresponding hydrazide 26 is formed. The reactions proceed under mild conditions, so that no racemization of chiral substituents was observed.
A convenient synthesis of 5‐acyl‐6‐substituted 3‐cyano‐2(1H)‐pyridinones
Authors: Jones Winton D. , Schnettler Richard A. , Huber Edward W.
Published: March 2009

2‐Dimethylaminomethylidene‐1,3‐diketones are useful synthons for the construction of 5‐acyl‐6‐substituted‐3‐cyano‐2(1H)‐pyridinones. The reaction of these 1,3‐diketones and the anion of cyanoacetamide gave the title compounds. When the 1,3 diketone contained different alkyl or aryl groups, mixtures of regioisomers were formed. To circumvent this problem, dimethylaminomethylidene hydrazones, regioselectively prepared from dimethylhydrazino enones and dimethylformamide dimethyl acetal were reacted with cyanoacetamide anion followed by acid hydrolysis to give the title compounds.
Reactions of 3‐isopropenyltropolones with bromine and N‐bromosuccinimide: Formation of 8H‐cyclohepta[b]furan‐8‐one derivatives
Authors: Jin Ren‐Hao , Yin Bing‐Zhu , Jin Zhong‐Tian , Imafuku Kimiaki
Published: March 2009

3‐Isopropenyltropolones 1a‐c were treated with bromine in carbon tetrachloride to give 3‐methyl‐8H‐cyclohepta[b]furan‐8‐ones 2a‐c and their corresponding 7‐bromo‐substituted compounds 3a‐c, while reactions in acetic acid gave the bromo‐substituted compounds 3a‐c. On the other hand, bromination of 1a‐c with N‐bromosuccinimide afforded 7‐bromo‐3‐(2‐bromo‐1‐methylethenyl)tropolones 5a‐c. The compound 2a was treated with bromine to give 2‐bromo‐3‐methyl‐8H‐cyclohepta[b]furan‐8‐one (4). The tropolones 5a‐c were heated in the presence of potassium carbonate to give the cyclized compounds 3a‐c.
Novel bicyclo[2.2.2]lactones from a facile condensation of dibenzoylethylene with arylacetonitriles
Authors: Atfah M. Adrian , Al‐Arab Mohammad M.
Published: March 2009

Several novel bicyclo[2.2.2]lactones were synthesized from a facile one‐pot reaction by the condensation of dibenzoylethylene and an arylacetonitrile in basic medium. The reaction proved to be convenient and gives high yield. The structure of the reaction products was established on the basis of their proton and carbon‐13 nuclear magnetic resonance, and infrared spectral data as well as their elemental analysis.
Lithiation of 1‐benzylimidazole. A hypothesis on the regioselectivity of the electrophilic attacks on the lithiated species
Authors: Moreno‐Mañas M. , Bassa J. , Lladó N. , Pleixats R.
Published: March 2009

Sequential lithiations of 1‐benzylimidazole, 1, and of 1‐benzyl‐1,2,4‐triazole, 2, followed by treatment with electrophiles others than alkyl halides result in reactions at C‐2. However, benzyl halides and, to a certain extent, iodomethane react at the N‐benzyl carbon atom. An explanatory hypothesis based on steric ortho effects is advanced.
Synthesis of 1‐acyl‐5‐pyrazolones and pyrrolidino[2,3‐c]pyrazol‐3‐ones
Authors: Cocco Maria Teresa , Congiu Cenzo , Maccioni Antonio
Published: March 2009

The reactivity of acetamidrazones I in strong basicity conditions was examined. When compounds I are reacted with equivalent quantities of α‐haloketones in sodium alcoholate, the pyrrolidino[2,3‐c]pyrazol‐3‐ones IV were obtained by intermediate formation of 1‐acyl‐3‐amino‐5‐pyrazolones III.
Pyrimidines. 65. Synthesis of 6‐substituted thieno[2,3‐d]pyrimidine‐2,4(1H,3H)‐diones
Authors: Hirota Kosaku , Shirahashi Mitsuomi , Senda Shigeo , Yogo Motoi
Published: March 2009

Several 6‐substituted thieno[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione derivatives were synthesized. 6‐Ethoxycarbonyl derivatives 3 and 7 were prepared by treatment of 6‐chloro‐5‐formyluracil 1 and 6‐chloro‐5‐cyanouracil 6 with ethyl 2‐mercaptoacetate in the presence of a base. Electrophilic substitution reactions (Vilsmeier‐Haack reaction, bromination, and nitration) of 5,6‐unsubstituted thieno[2,3‐d]pyrimidine 9, prepared by condensation of 6‐mercaptouracil 8 with chloroacetaldehyde, afforded the corresponding 6‐formyl‐, 6‐bromo‐, and 6‐nitrothieno[2,3‐d]pyrimidines 10, 15 and 16, respectively.
Syntheses of 6‐Amino‐1‐(β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]‐1,3‐oxazin‐4‐one, an isostere of oxanosine, and the guanosine analog 6‐amino‐1‐(β‐d‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidin‐4(5H)‐one via ring closure of pyrazole‐5‐thioureido intermediates
Authors: Bhattacharya Birendra K. , Robins Roland K. , Revankar Ganapathi R.
Published: March 2009

6‐Amino‐1‐(β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]‐1,3‐oxazin‐4‐one (4), an isostere of the nucleoside antibiotic oxanosine has been synthesized from ethyl 5‐amino‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)pyrazole‐4‐carboxylate (6). Treatment of 6 with ethoxycarbonyl isothiocyanate in acetone gave the 5‐thioureido derivative 7, which on methylation with methyl iodide afforded ethyl 1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐5‐[(N'‐ethoxycarbonyl‐S‐methylisothiocarbamoyl)amino]pyrazole‐4‐carboxylate (8). Ring closure of 8 under alkaline media furnished 6‐amino‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]‐1,3‐oxazin‐4‐one (10), which on deisopropylidenation afforded 4 in good yield. 6‐Amino‐1‐(β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidin‐4(5H)‐one (5) has also been synthesized from the AICA riboside congener 5‐amino‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)pyrazole‐4‐carboxamide (12). Treatment of 12 with benzoyl isothiocyanate, and subsequent methylation of the reaction product with methyl iodide gave 1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐5‐[(N'‐benzoyl‐S‐methylisothiocarbamoyl)amino]pyrazole‐4‐carboxamide (15). Base mediated cyclization of 15 gave 6‐amino‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidin‐4(5H)‐one (14). Deisopropylidenation of 14 with aqueous trifluoroacetic acid afforded 5 in good yield. Compound 4 was devoid of any significant antiviral or antitumor activity in culture.
Regioselective synthesis of trifluoromethylated pyrazoles by selective protection of trifluoromethyl‐β‐diketones
Authors: Lyga John W. , Patera Russell M.
Published: March 2009

1,1,1‐Trifluoropentane‐2,4‐dione was selectively protected by treatment with pyrrolidine to give 6. The reaction of 6 with arylhydrazines gave 5 exclusively. The structural assignment for 5 was confirmed by quenching the dianion of 8 with ethyl trifluoroacetate.
Furan derivatives. part 11 [1]. on substituent effects in the synthesis of 3,4,5,6‐tetrahydrocyclohepta[cd]benzofurans
Authors: Horaguchi Takaaki , Kobayashi Hiroto , Miyazawa Kazuhiro , Hasegawa Eietsu , Shimizu Takahachi , Suzuki Tsuneo , Tanemura Kiyoshi
Published: March 2009

Tetrahydrocyclohepta[cd]benzofurans 7a‐e were synthesized by the treatment of (5‐oxo‐tetrahydro‐5H‐benzocyclohepten‐4‐yloxy)acetic acids 5a‐e with sodium acetate in acetic anhydride or by heating of their esters 6a‐e with sodium hydroxide or sodium hydride in dioxane. The yield of furans 7 decreased as a substituent R of acids 5 or esters 6 was changed from hydrogen to a methyl, ethyl, or isopropyl group. When R was a phenyl group furan 7e was always prepared in good yield. Sodium hydride was a useful base for synthesis of tetrahydrocyclohepta[cd]benzofurans.
Synthesis of novel pyrido[3,4‐f]pyrrolo[1,2‐b][1,2,5]triazepines. A Novel heterocyclic ring system
Authors: Effland Richard C. , Davis Larry , Kapples Kevin J. , Olsen Gordon E.
Published: March 2009

The synthesis of novel pyrido[3,4‐f]pyrrolo[1,2‐b][1,2,5]triazepines 6–17 is described. Subsequent reactions on the parent system include reduction, Grignard addition, alkylation, acylation and carbamoylation.
Synthesis of some N‐[pyridyl(phenyl)carbonylamino]‐alkyl‐1,2,3,6‐tetrahydropyridines
Authors: Redda Kinfe K. , Melles Hailemichael , Rao Kode Nageswara
Published: March 2009

Alkyl substituted 2,4‐dinitrophenylpyridinium chlorides 3 are formed by the nucleophilic substitution of 1‐chloro‐2,4‐dinitrobenzene with alkyl pyridines. Reaction of pyridyl acid hydrazides or benzoyl hydrazides 4 with the pyridinium chlorides 3 furnish the isolable 2,4‐dinitroanilino derivatives 5 which undergo hydrolysis when refluxed in water:p‐dioxane mixture (1:4 v/v) to yield the pyridinium ylides 6. Sodium borohydride reduction of 6 in absolute ethanol at 0° for 4 hours result the formation of the title compounds 7 in moderate to excellent yields.
Synthesis of pyridines by heterocyclization of new dienamino esters
Authors: Cocco Maria Teresa , Congiu Cenzo , Maccioni Antonio
Published: March 2009

The synthesis of pyridine derivatives is reported starting from the new dienamino esters 2. Thermal cyclization of 2 afforded the ethyl 2‐amino‐3‐pyridinecarboxylate derivatives 3; from the reaction of 2 in sodium ethoxide the 2‐aminopyridines 3 and 4, and the 1,2‐dihydro‐2‐oxopyridines 5 and 6 were obtained.
A novel synthesis of the isoxazolo[5,4,3‐kl]acridine ring system
Authors: Shutske Gregory M.
Published: March 2009

The Schmidt reaction of 6,7‐dihydro‐3‐phenyl‐1,2‐benzisoxazol‐4(5H)‐one (1) is described. In addition to the expected isomeric lactams, 3‐phenyl‐5,6,7,8‐tetrahydro‐4H‐isoxazolo[4,5‐c]azepin‐4‐one (3) and 7,8‐dihydro‐3‐phenyl‐4H‐isoxazolo[4,5‐b]azepin‐5(6H)‐one (4), 4‐amino‐3‐phenyl 1,2‐benzisoxazole (5) was isolated, along with 4,5‐dihydro‐3H‐isoxazolo[5,4,3‐kl]acridine (6). Possible mechanisms for the formation of these products are discussed and some chemistry of the little‐known ring system represented by 6 is also described.
Preparation and reactivity of polyfunctional phenazine derivatives
Authors: Lehn Jean‐Marie , Schmidt Frédéric , Vigneron Jean‐Pierre
Published: March 2009

Treatment of 2,3,6,7‐tetramethylphenazine with N‐bromosuccinimide under light irradiation afforded in good yield the tetrakis(bromomethyl) derivative. Weakly basic nucleophilic reagents such as thiols, phenols, amines and the azide anion allow the preparation of a variety of functionalized derivatives. Some 2,7‐disubstituted phenazines have also been obtained.
Selective lateral metalation and electrophilic quenching of c‐4 functionalized isoxazoles. IX. Direct formation of the C‐N bond utilizing an electrophilic nitrogen source
Authors: Mirzaei Yousef R. , Balasubramaniam T. N. , Lefler Barbara J. , Natale N. R.
Published: March 2009

C‐5 Lithio‐alkylisoxazoles were quenched with dialkyl azodicarboxylates to form the C‐5 alkylhydrazine derivatives in synthetically useful yields.
A new heterocyclic structure. The Benzopyrano[6,5,4‐def] Benzopyran. (1,6‐dioxapyrene)
Authors: Buisson Jean‐Pierre , Demerseman Pierre
Published: March 2009

1,6‐Dioxapyrene, the first unsubstituted dioxa‐analogue of pyrene was synthesized in good yield from 2‐carbomethoxy‐6‐methoxynaphtho[1,8‐bc]pyran in a four‐step reaction involving a peri‐heterocyclisation. Its 1H nmr spectral characteristics were compared with those of native pyrene.
Synthesis of 3‐cyano‐2‐methylpyridines substituted with heteroaromatics
Authors: Shibata Katsuyoshi , Katsuyama Isamu , Matsui Masaki , Muramatsu Hiroshiga
Published: March 2009

A series of title compounds were easily prepared by the sonication of α,β‐unsaturated carbonyl compound in acetonitrile in the presence of potassium t‐butoxide.
Electron ionization mass spectra of some 4β‐phenyl‐substituted cycloalkane‐cis‐fused 1,3‐oxazin‐2(3H)‐ones, ‐2(3H)‐thiones and 1,4‐oxazepin‐3(4H)‐ones
Authors: Vainiotalo Pirjo , Ronkanen Sari , Stájer Géza , Bernáth Gábor , Pihlaja Kalevi
Published: March 2009

The 70 eV mass spectra of 4β‐phenyl‐substituted cyclopentane‐ and cyclohexane cis‐fused 1,3‐oxazin‐2(3H)‐ones, the two related 2‐thiones, 6,7‐cis‐trimethylene‐5β‐phenyl‐1,4‐oxazepin‐3(4H)‐one and its 2β‐methyl derivative were recorded and their fragmentations examined by means of metastable ion analysis, collision induced dissociation technique and exact mass measurement. The fragmentation patterns of the 1,3‐oxazin‐2(3H)‐ones were relatively simple: the favored formation of cycloalkene ions implied that a considerable proportion of the molecular ions might possess an enol structure. Changes in the size of the fused cycloalkane ring had little or no effect on the fragmentations. Instead, small changes in the heterocyclic part of the molecule caused remarkable effects on the fragmentation behavior. Compared to 1,3‐oxazin‐2(3H)‐ones studied, both 1,3‐oxazine‐2(3H)‐thiones and 1,4‐oxazepin‐3(4H)‐ones showed much more complicated fragmentation patterns.
Preparation and some reactions of 3,5:8,10‐di‐1,3‐benzo[8](3,4)‐1,2,5‐thiadiazolocyclophane
Authors: Hatta Taizo , Mataka Shuntaro , Tashiro Masashi , Suzuki Hiroshi , Numano Katsutoshi
Published: March 2009

Titled 1,2,5‐thiadiazolometacyclophane 1 was prepared via thia[2.3]cyclophane 5 which was obtained by the reaction of di(bromomethyl) 2 with sodium sulfide under phase‐transfer‐catalyzed conditions. Cyclophane 1 gave the corresponding pyrene derivatives by the oxidative transannular reaction in the reaction with brominating reagent. Reduction of 1 with lithium aluminum hydride followed by acetylation with acetic anhydride gave a 4:l‐mixture of cis‐ and trans‐diamide 11 and 12 with a trace amount of cyclophane‐ring‐cleaved product 13. On the other hand, 13 was obtained as a major product in the reduction with metal sodium and diisobutylaluminum hydride.
Reactions of 2,3‐bishydroxyimino‐1,2,3,4‐tetrahydro‐quinoxalines and 2,3‐bishydroxyimino‐2,3‐dihydro‐4H‐1,4‐benzoxazines with ethyl chloroformate
Authors: Varella Evangelia A. , Nicolaides Demetrios N.
Published: March 2009

Bishydroxyiminoquinoxalines 3a‐b react with ethyl chloroformate 4 to afford the furazano[3,4‐b]quinoxalines 5a‐b. Bishydroxyiminobenzoxazines 6a‐c on treatment with 4 are converted into the fused oxadiazolones 7a‐c and 8a‐c along with the bisethoxycarbonyloxyimino‐derivatives 9a‐c. From the reactions of 4 with the oxanilide dioximes 12a‐c compounds 13a‐c and 14a‐b are obtained.
Saturated heterocycles. 176 Synthesis and steric structure of quaternary azeto[2,1‐a]isoquinoline stereoisomers
Authors: Bernáth Gábor , Fölöp Ferenc , Árva Judit , Kóbor Jenö , Sohár Pál
Published: March 2009

Starting from 1‐substituted azeto[2,1‐a]isoquinoline diastereomers, a number of quaternary salts were prepared. The reactions leading to the quaternary salts were stereospecific, independently of the configuration at C‐1, resulting in diastereomers. The steric structures of the new compounds were proved by nmr spectroscopy.
1,3‐Dipolar cycloadditions of diazoalkanes to pyridazine derivatives. Thermal 1,5‐sigmatropic rearrangement of methyl groups in 3,3‐dimethyl‐3H‐pyrazolo[3,4‐d]pyridazine derivatives
Authors: Stanovnik Branko , Jelen Boris , Štimac Anton , Tišler Miha
Published: March 2009

Thermal 1,5‐sigmatropic rearrangements of one of the methyl group attached at position 3 of 3,3‐dimethyl‐3H‐pyrazolo[3,4‐d]pyridazin‐4(5H)‐ones 1–3 taking place either in a clock‐wise or anti‐clockwise direction gave N2‐methylated products 4–6 and C3a‐methylated products 7–9. The ‐7(6)‐one derivative 10 and ‐4,7(5H,6H)‐dione derivative 12 gave only N2‐methylated products 11 and 13 respectively, and 1,2‐dihydro derivative 14 produced after elimination of methane, 15.
Electrophilic benzylation of 2‐aminopyridine ring
Authors: Kowalski Piotr
Published: March 2009

In the reaction of 2‐aminopyridine and its 3‐ or 5‐methyl derivatives with benzyl chloride used in a molar ratio of 1:2, benzylation of 2‐aminopyridine ring has been stated that 2‐amino‐3‐ or 5‐benzylpyridines c as the major products were obtained. Formation of c type compounds took place in the decomposition of 2‐benzylamino‐3‐ or 5‐benzylpyridines b obtained in the reaction of the 2‐benzylaminopyridines a, excess benzyl chloride was used. Production of the b and c compounds, where the benzyl substituent occupied position 3 or 5 in 2‐aminopyridine supported the electrophilic mechanism of the reaction (radical reaction was excluded). In the case of 2‐aminopyridine and its 3‐methyl derivative bis‐(2‐amino‐5‐pyridyl)phenylmethanes d were formed as the by‐products.
Conjugated macrocycles related to the porphyrins. Part 2. Further synthetic and spectroscopic studies on difuryl analogs of the oxophlorins
Authors: Lash Timothy D. , Armiger Yoek Lin See‐Tow
Published: March 2009

The synthesis of three difuryl analogs of the oxophlorins is described. In common with the tetrapyrrolic oxophlorins, these compounds favor the keto tautomers and little, if any, of the enol tautomers are present in neutral solutions. Unlike the tetrapyrrolic systems, the difuryl oxophlorins give well resolved nmr spectra. Attempts to extend these studies to the synthesis of dithienyl oxophlorin analogs were unsuccessful.