bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and characterization of aliphatic polyurethane and hydroxyapatite composite scaffold
Authors: Liu Haohuai , Zhang Li , Zuo Yi , Wang Li , Huang Di , Shen Juan , Shi Pujiang , Li Yubao
Published: March 2009

Novel porous composite scaffolds for tissue engineering were prepared from aliphatic biodegradable polyurethane (PU) elastomer and hydroxyapatite (HA). It was found that the aliphatic PU was possible to load up to 50 wt % HA. The morphology and properties of the scaffolds were characterized by scanning electron microscope, X‐ray diffraction, infrared absorption spectra, mechanical testing, dynamic mechanical analysis, and in vitro degradation measurement. The results indicated that the HA/PU scaffolds had an interconnected porous structure with a pore size mainly ranging from 300 to 900 μm, and 50–200 μm micropores existed on the pores' walls. The average pore size of macropores and micropores are 510 and 100 μm, respectively. The compressive strength of the composite scaffolds showed higher enhancement with increasing HA content. In addition, the polymer matrix was completely composed of aliphatic component and exhibited progressive mass loss in vitro degradation, and the degradation rate depended on the HA content in PU matrix. The porous HA/PU composite may have a good prospect to be used as scaffold for tissue engineering. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of scratch and mar resistant waterborne epoxy/silica nanocomposite clearcoat
Authors: Chen Songwei , You Bo , Zhou Shuxue , Wu Limin
Published: March 2009

Colloidal nano‐silica particles were used to improve the scratch and mar resistance of waterborne epoxy coatings by directly blending. To enhance the compatibility of nano‐silica particles within polymer matrix, nano‐silica particles were first modified with 3‐glycidoxypropyl‐trimethoxysilane (GPTMS) and characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The modified nano‐silica particles were found to have a better dispersion and compatibility in the polymer matrix than the unmodified nano‐silica particles. Macro‐scratch and nano‐scratch testers were employed to characterize the scratch and mar resistances of the nanosilica‐reinforced epoxy coatings. Relative to unmodified nano‐silica, GPTMS‐modified nano‐silica particles can improve the scratch and mar resistance more significantly and reduce the transparency and gloss of waterborne epoxy coatings less seriously. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Distal biceps brachii tendon anatomy revisited from a surgical perspective
Authors: Fogg Quentin A. , Hess Benjamin R. , Rodgers K. Gary , Ashwood Neil
Published: March 2009

The distal biceps brachii tendon is commonly susceptible to traumatic injury. This study aimed to describe the morphology of the distal biceps brachii tendon in relation to the commonly used endobutton repair of tendon rupture. The results suggested that the distal tendon is a series of distinct bands of variable number. These bands are obscured surgically by the tendon sheath. Upon opening this sheath, blunt dissection of the tendon released fibrous connections between the tendon bands. Adjacent bands were variably connected via small oblique bands. The separations between bands were continuous onto the radius. They were therefore considered as separate force‐conducting units. This notion is of high relevance to endobutton repairs, as the sutures are typically only passed through the margins of the tendon. Where few connections exist between tendinous bands, this represents a potential weakness, as central bands are therefore free to be pulled proximally. This is of primary concern in the early rehabilitative stages of postoperative care. It may be suggested that sutures that cross the width of the tendon will eliminate the give of central bands, improving postoperative results, reducing revision numbers, and potentially reducing rehabilitation time. Clin. Anat. 22:346–351, 2009. © 2009 Wiley‐Liss, Inc.
Application of seeded batch crystallization methods for reduction of the scaling tendency of seawater – A study of growth kinetics of calcium carbonate in seawater
Authors: Omar W. , Chen J. , Ulrich J.
Published: March 2009

The objective of this study is to evaluate the applicability of a seeded batch crystallization method as a pre‐treatment stage to the reduction of the the scaling potential of seawater. The crystallization process of calcium carbonate in supersaturated seawater is studied experimentally in a seeded batch crystallizer. Results show that the initial pH value of seawater must be adjusted to be in the range of 8‐9. Calcite seeds will not have the potential to start the growth process in seawater at he the normal pH (7.36) compared to the above mentioned range. The growth kinetic parameters are determined from the measured desupersaturation curves. It is found that the growth process of calcite is controlled by surface integration step. The growth rate of calcite increases with increasing temperature and seeding ratio (up to 1 g/L), while it decreases with increasing the salinity of seawater. Crystals of calcite morphology are found to be growing faster than seeds of aragonite morphology. Stirrer speed has no distinct effect on the growth rate of calcite in seawater. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal structure characterization of the quaternary compounds CuFeAlSe3 and CuFeGaSe3
Authors: Delgado G. E. , Mora A. J. , Contreras J. E. , Grima‐Gallardo P. , Durán S. , Muñoz M. , Quintero M.
Published: March 2009

The crystal structure of the chalcogenide compounds CuFeAlSe3 and CuFeGaSe3, belonging to the system I‐II‐III‐III3, were characterized using X‐ray powder diffraction data. Both compounds crystallize in the tetragonal space group P42c (N° 112), Z = 1, with unit cell parameters a = 5.609(1) Å, c = 10.963(2) Å for CuFeAlSe3 and a = 5.6165(3) Å, c = 11.075(1) Å for CuFeGaSe3. These compounds are isostructural with CuFeInSe3, and have a normal adamantane structure. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A demand side approach for congestion management in competitive environment
Authors: Shayesteh E. , Moghaddam M. P. , Yousefi A. , Haghifam M.‐R. , Sheik‐El‐Eslami M. K.
Published: March 2009

This paper proposes an approach for transmission congestion management (CM) in a deregulated power system. Transmission congestion mitigates network efficiency and results in increasing electricity price. Congestion can be effectively eliminated through several methods either by building a new transmission line or by increasing the capacity of the original line between congested zones. This paper evaluates the using of Demand Response (DR) programs in order to managing the congestion. For this purpose, a coordination process between GENCOs and the Independent System Operator (ISO) is considered. In the proposed approach, the coordination is modeled as a two‐stage process. At first, GENCOs apply price‐based unit commitment and submit their bids to the ISO for maximizing their profits. Then, the ISO clears the market using Day‐Ahead Demand Response Program (DADRP). Now, if any transmission violation exists, the ISO will run re‐dispatching of GENCO bids using Emergency Demand Response Program (EDRP) for minimizing the CM cost as well as omitting line flow violations. Numerical studies based on IEEE 57‐bus system are performed for the evaluation of the method. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of mechanical stimuli on the synthesis of superficial zone protein in chondrocytes
Authors: Kamiya T. , Tanimoto K. , Tanne Y. , Lin Y. Y. , Kunimatsu R. , Yoshioka M. , Tanaka N. , Tanaka E. , Tanne K.
Published: March 2009

Superficial zone protein (SZP) has been demonstrated to contribute to the boundary lubrication in synovial joints. This study was designed to clarify the modulation of SZP expression by mechanical stress in articular chondrocytes. Cyclic tensile strains of 7 and 21% cell elongation were applied to cultured chondrocytes obtained from porcine mandibular condylar cartilage. The mRNA levels of SZP, IL‐1β, and TGF‐β1 were examined by a quantitative real‐time PCR analysis. Protein level of SZP was examined by Western blotting. The SZP mRNA level was significantly upregulated after 12, 24, and 48 h by 7% elongation. Although SZP mRNA level was upregulated by 21% elongation after 12 h, it decreased to a lower level than the control after 48 h. The TGF‐β1 mRNA level exhibited an almost similar change to SZP. The IL‐1β mRNA level was not changed markedly by 7% elongation. However, the IL‐1β mRNA level was significantly increased by a 12‐h application of 21% elongation. Western blot analysis revealed that the SZP expression was increased by 7% elongation, but decreased remarkably by 21% elongation. It is suggested from these findings that the SZP expression level in the chondrocytes is enhanced by optimal mechanical stimuli, but inhibited by excessive loading partly affected by TGF‐β1 and IL‐1β, leading to the deterioration of joint lubrication. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Can low frequency electromagnetic field help cartilage tissue engineering?
Authors: Chang Chih‐Hung , Loo Siow‐Tung , Liu Hsuan‐Liang , Fang Hsu‐Wei , Lin Hsin‐Yi
Published: March 2009

To understand whether a low‐frequency pulsed electromagnetic field (EMF) could help cartilage tissue repair in the scope of tissue engineering, we tested how EMF affected collagen gel properties and the behaviors of chondrocyte cells embedded in collagen constructs. Collagen gel and primary chondrocytes embedded in collagen were exposed to EMF for 24 h. Gel and cells that were not exposed to EMF served as controls. Collagen gel exposed to EMF was more hydrophobic and less susceptible to enzymatic degradation (both p < 0.05) than control. Three weeks after EMF exposure, chondrocytes showed higher proliferation and lower glycosaminoglycan (GAG) production (both p < 0.05) than control. By the end of the third week, aggrecan, type I, II, and X collagen mRNA expressions in the EMF group were 1.8 times higher (p < 0.05), except for type II collagen) than control. The increase in gene expression did not show up in aggrecan histological staining and type II and type X collagen immunohistochemical staining. Cells from both groups kept a normal polygonal shape through out the test period. Our results suggested that one‐time EMF exposure could promote collagen‐embedded chondrocytes proliferation and their gene expressions. It also promoted short‐term (week 1) GAG production and lacuna formation. No apparent GAG and type II collagen production was seen in histological staining three weeks after the EMF exposure. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Ring opening reactions of 6H‐anthra[1,9‐cd]isoxazol‐6‐ones and related compounds
Authors: Sutter P. , Weis C. D.
Published: March 2009

Nucleophilic attack of anthra[1,9‐cd]isoxazol‐6‐ones, and of anthra[1,9‐cd:5,10‐c'd']isoxazole by various sulfoxides, triphenyl phosphine, and aliphatic or aromatic phosphites proceeded with cleavage of the nitrogenoxygen bond of the isoxazole ring. This method provided ready access to substituted anthraquinones bearing sulfoximido‐, triphenylphosphazo‐, and dialkyl(aryl)phosphoramidic groups attached to the 1‐ and the 1,5‐positions of the anthraquinone system. The structures of the newly synthesized anthraquinone derivatives were supported by analytical and spectral data. l‐S,S‐dimethyl‐N‐(5‐benzamidoanthraquinon‐1‐yl)‐sulfoximide yielded in 90% sulfuric acid the l‐amino‐5‐sulfoximido anthraquinone without hydrolyzing the sulfoximido group.
The 1‐alkoxy‐6‐nitro‐1,2,3‐benzotriazole system
Authors: Jung P. , Seybold P. G. , Servé M. P.
Published: March 2009

The 1‐alkoxy‐6‐nitro‐1,2,3‐benzotriazole system has been synthesized and characterized via its physical and chemical properties. INDO/molecular orbital calculations provide a good account of the major bands in its ultraviolet absorption spectrum.
N‐polyazolylmethanes. 1. Synthesis and nmr study of N,N′‐diazolylmethanes
Authors: Juliá Sebastian , Sala Pilar , Del Mazo José , Sancho Manuel , Ochoa Carmen , Elguero JosÉ , Fayet Jean‐Pierre , Vertut Marie‐Claire
Published: March 2009

Thirteen N,N‐diazolylmethanes, including derivatives of pyrazole, imidazole, 1,2,4‐triazole, benzimidazole and indazole were prepared by reaction of azoles with methylene chloride under phase transfer catalysis conditions. The relative amounts of isomeric mixtures obtained with ‘asymmetric’ azoles or with equimolar mixtures of azoles are compared with literature results on monoalkylation of azoles. Proton and carbon‐13 nmr spectra of the N,N'‐diazolylmethanes are discussed.
Synthesis of esters of 4‐hydroxy‐5‐phosphinyl‐2‐imidazolidinone
Authors: Mikroyannidis John A. , Tsolis Alexandros K.
Published: March 2009

The esters of 4‐hydroxy‐5‐phosphinyl‐2‐imidazolidinone were prepared by reaction of urea with the esters of 2‐hydroxy‐2‐phosphinylethanal in acidic medium. The ir, 1H nmr and 31P nmr spectral data of the products are reported. All the isolated products had cis configuration. The stereochemistry of their formation is discussed.
Preparation of new 1,2,4‐triazines
Authors: Repič Oljan , Mattner P. G. , Shapiro M. J.
Published: March 2009

Several 1,2,4‐triazines were synthesized. 13C‐ and 15N‐nmr spectroscopy was employed for structure determination.
A reliable synthesis of 1,1‐dimethylpyrazolium 5‐oxides
Authors: Ellis Jerry W. , Keiter Ellen A. , Keiter Richard L. , Li Tso‐Ping , Uptmor Robert A.
Published: March 2009

Reliable syntheses of compounds having the novel 1,1‐dimethylpyrazolium 5‐oxide ring system are reported. The method involves treating the dimethylhydrazone of a β‐ketoester with a small amount of concentrated sulfuric acid or other catalyst and heating under reduced pressure for 1–24 hours. In this manner two new members of the series have been prepared and characterized.
Diazotization of a 2‐amino‐1,3‐selenazole
Authors: Archer Sydney , McGarry Ruthann
Published: March 2009

Diazotization of 5‐(acetoxyethyl)‐2‐amino‐4‐methylselenazole with nitrosoborofluoride in the presence of sodium fluoride in fluoboric acid solution furnishes 5‐(acetoxyethyl)‐2‐fluoro‐4‐methylselenazole and the corresponding 2‐hydroxy compound. Despite low yields, this was the first time that a Sandmeyer‐Schiemann reaction has been carried out successfully with 2‐aminoselenazoles.
Some reactions of 1‐methyl‐1,2,3,4‐tetrahydropyridine with organic azides. Synthesis of 1‐methylpiperidylidene‐2‐sulfon(cyan)amides
Authors: Warren B. K. , Knaus E. E.
Published: March 2009

The 1,3‐dipolarcycloaddition reaction of 1‐methyl‐1,2,3,4‐tetrahydropyridine (1) with organic azides 2 affords 1‐methylpiperidylidene‐2‐sulfon(cyan)amides 4 in high yield. The reaction proceeds via a 2,3,4,9‐tetrazabicyclo[4.3.0]non‐3‐ene intermediate. Acid hydrolysis of 4d gives rise to 1‐methyl‐2‐piperidone.
Synthesis of potential antineoplastic agents. XXVII. (Reissert compound studies. XLIV.). The ellipticine reissert compound as an intermediate in the syntheses of ellipticine analogs
Authors: Popp Frank D. , Veeraraghavan Seshadri
Published: March 2009

Ellipticine and a number of ellipticine analogs were converted to Reissert compounds. Alkylation of the 6‐benzylellipticine Reissert compound gave a series of 1‐substituted‐6‐benzylellipticines. 1‐Cyanoellipticine, obtained through the Reissert compound, was hydrolyzed to ellipticine‐1‐carboxamide hydrochloride which was active against P388 lymphocytic leukemia. Other aspects of the chemistry of the ellipticine Reissert compound are presented.
Reaction of N‐(2‐pyridylmethyl)‐3,5‐dimethylbenzamide and N‐(3‐pyridylmethyl)‐3,5‐dimethylbenzamide N‐oxides with acetic anhydride
Authors: Braña Miguel F. , Rodriguez María Luz López
Published: March 2009

As a continuation of our work on the reaction of N‐pyridylmethyl‐3,5‐dimethylbenzamide N‐oxides with acetic anhydride, we now report a study of the reaction of N‐(2‐pyridylmethyl)‐3,5‐dimethylbenzam.de N‐oxide (5) and N‐(3‐pyridylmethyl)‐3,5‐dimethylbenzamide N‐oxide (6) with acetic anhydride. Compound 5 gave N,N′‐di(3,5.dimethylbenzoyl)‐1,2‐di(2.pyridyl)ethenediamine (7) and 3,5‐dimethylbenzamtde (8). Compound 6 afforded three products formulated as 2‐acetoxy‐3‐(3,5‐dimethylbenzoylaminomethyl)pyridine (12), 3‐(3,5‐dimethylbenzoylaminomethyl)‐2‐pyridone (13) and 5‐(3,5‐dimethylbenzoylaminomethyl)‐2‐pyridone (14). Analytical and spectral data are presented which support the structures proposed.
Vierring‐synthesen durch [3 + 1]‐cycloaddition . Synthese von 3‐imino‐azetidinen aus azomethin‐yliden und isonitrilen
Authors: Burger Klaus , Marschke Gregor , Manz Friedrich
Published: March 2009

Azomethine ylide 3, generated by thermolysis of 3,4‐diphenyl‐Δ1‐1,2,3‐triazoline‐5,5‐dimethyldicarboxylate 1, can be trapped by isonitriles to give 3‐imino‐1,4‐diphenylazetidine‐2,2‐dimethyldicarboxylates 5. The IR, 1H‐NMR, 13C‐NMR and mass spectral data of the new compounds are discussed.
The cyclization of N,N′‐bis[2‐(dialkoxy)ethyl]‐p‐xylene‐α,α′‐diamine dihydrochloride to pyrido[3,4‐g]isoquinoline and 3,8‐phenanthroline
Authors: Schwan Thomas J. , Miles Nelson J.
Published: March 2009

The ring closure of N,N′‐bis[2‐(dialkoxy)ethyl]‐p‐xylene‐α,α′‐diamine dihydrochloride in fuming sulfuric acid has been investigated and the cyclization products have been identified as the linear pyrido[3,4‐g]isoquinoline as well as the previously reported angular 3,8‐phenanthroline.
Carbon‐13 NMR characterisation of carboxyl derivatives of 1‐ureidopyrroles
Authors: Lamartina Liliana , Migliara Onofrio , Sprio Vincenzo
Published: March 2009

1‐Ureido‐5‐methyl‐2,3‐dicarbethoxypyrrole under acidic conditions afforded different partially hydrolyzed or decarboxylated products. It has been possible to characterize two isomeric monoethyl esters of dicarboxylic acids of 1‐ureidopyrroles by proton gated decoupled carbon‐13 nmr spectra on the basis of multiplicities of the carbonyl carbons resonances.
Chemistry of the phenoxathiins and isosterically related heterocycles. XXIII . 1‐azathianthrene: First reported synthesis of a monoazathianthrene and the investigation of the 13C‐NMR spectrum using two‐dimensional NMR techniques
Authors: Puig‐Torres Salvador , Martin Gary E. , Ford Joseph J. , Willcott M. Robert , Smith Keith
Published: March 2009

The reaction of the dianion of 3‐mercaptopyridin‐2(1H)‐thione with 2‐chloronitrobenzene in N,N‐dimethylformamide leads to the formation of 1‐azathianthrene, the first reported mono‐aza analog of the thianthrene ring system. A partial assignment of the 13C‐nmr spectrum of the title compound is reported, the assignment based on chemical shift arguments, spin‐lattice (T1) relaxation times and 1H‐13C spin coupling constants. Amplitude modulated two‐dimensional Fourier transform (AM2DFT) techniques were employed for the acquisition of the heteronuclear spin‐coupling constants.
Chemistry of the phenoxathiins and isosterically related heterocycles. XXIV . Synthesis of characterization by 13C‐NMR spectroscopy of isomeric benzoxathiinopyridazinones: 1‐Oxo‐1,2‐dihydro‐2,3‐diazaphenoxathiin and 4‐Oxo‐3,4‐dihydro‐diazaphenoxathiin. The first observation of a smiles rearrangement involving divalent sulfur during the synthesis of an azaphenoxathiin
Authors: Womack Charles H. , Martin Linda M. , Martin Gary E. , Smith Keith
Published: March 2009

Condensation of the disodium salt of o‐mercaptophenol with 4,5‐dichloro‐6(1H)‐pyridazinone in N,N‐dimethylformamide has been observed to lead to the formation of both possible isomeric benzoxathiinopyridazinones. The separation of these isomers, 1‐oxo‐1,2‐dihydro‐2,3‐diazaphenoxathiin and 4‐oxo‐3,4‐di‐hydro‐2,3‐diazaphenoxathiin and their characterization by 13C‐nmr spectroscopy is described. Mechanisms to account for the formation of both isomers are discussed, the most probable mechanism involving a Smiles rearrangement of the phenolate sulfide intermediate formed by the initial displacement of the 4‐chloro substituent, providing a specie analogous to a β‐halovinylogous ketone.
Regioselective aziridine ring expansions
Authors: Clough Stuart C. , Solomon Robert , Crews Elain , Jaques Larry , Johnson Ashby , Forehand John
Published: March 2009

1‐Phenylmethyl‐2‐hydroxymethylaziridine (1) undergoes regioselective reactions with carbon disulfide to form thiazolidinethiones. Deuterium labeling experiments suggest that the reaction proceeds exclusively via aziridinium ring expansion. The regiospecificity appears to be electronically controlled.
Pyrrolo[1,4]benzodiazepines. III. synthesis of 5,11‐dioxo‐1,10,11,11a‐tetrahydro‐2‐vinyl‐5H‐pyrrolo[2,1‐c][1,4]benzodiazepine
Authors: Massa S. , De Martino G. , Corelli F.
Published: March 2009

Some pyrrolo[2,1‐c][1,4]benzodiazepines having a chain of two carbon atoms, as it is found in antibiotic tomaymycin, were prepared. The first reaction was the C‐acetylation of 1‐(2‐nitrobenzoyl)‐Δ4‐pyrroline‐2,2‐dicarboxylic acid diethyl ester; successive transformations of the acetyl group and cyclization gave the proposed structures.
Degradation products of 3‐phenylmethylpyrido[3,4‐e]‐1,2,4‐triazine
Authors: Michels Julian G.
Published: March 2009

The thermal degradation of 3‐phenylmethylpyrido[3,4‐e]‐1,2,4‐triazine (I) leads to a large number of compounds. The isolation and identification of two of these is described.
A facile preparation of 4‐(1‐Acetyl‐4(1H)‐pyridylidene)‐2‐oxazohn‐5‐ones
Authors: Hirota Kazuhiro , Shimamura Michiya , Ikeda Mikiko , Ohmori Shinji
Published: March 2009

4‐(1‐Acetyl‐4(1H)‐pyridylidene)‐2‐oxazolin‐5‐ones were prepared by the reaction of acylglycines with pyridine and acetic anhydride under oxygen. Acidic and alkaline hydrolysis of 2‐oxazolin‐5‐ones provided oxazole derivatives, pyridine derivatives, and carboxylic acids.
Phase transfer catalysis in N‐alkylations of the pharmaceutical intermediates 5H‐dibenz[b,f]azepine and 5H‐10,11‐dihydrodibenz[b,f]azepine
Authors: Gozlan Igal , Halpern Marc , Rabinovitz Mordecai , Avnir David , Ladkani David
Published: March 2009

The two title compounds were alkylated under very mild phase‐transfer‐catalysis conditions. Differences in reactivities of the two heterocyclic nucleophiles, and in the reactivities of various alkyl halides are discussed.
Acid catalyzed chlorination of pyrrole with N‐chloroacetanilide
Authors: de Rosa Michael
Published: March 2009

The chlorination of pyrrole with N‐chloroacetanilide was catalyzed by acetic acid. Transfer of Cl+ occurred directly to the α and β positions of pyrrole and a mixture of 2‐chloro‐, 3‐chloro‐ and 2,5,‐dichloropyrrole was formed. The α↗β ratio was 10:1 under competitive conditions.
Pyrrolothienopyrazines: Synthèse de la pyrrolo[1,2‐a]thieno[3,2‐e]pyrazine et de la pyrrolo[1,2‐a]thieno[2,3‐e]pyrazine
Authors: Rault Sylvain , Effi Yamien , De Sevricourt Michel Cugnon , Lancelot Jean‐Charles , Robba Max
Published: March 2009

La synthèsis de la pyrrolo[1,2‐a]thiéno[3,2‐e]pyrazine et de la pyrrolo[1,2‐a]thiéno[2,3‐e]pyrazine est étudiée. Elle est réalisable par cyclisation intramoléculaire cyclization des (pyrrol‐1)‐2(et‐3) ‐thienylamines‐3 (et‐2) qui peuvent ě obtainus par hydrolyse des carbamates ou par scission des urěes correspondantes. une seconde voice de synthése original autorisant de meilleurs résultants a été développée avec mise en oeuvre d'un réarrangement de Curtius qui oppose un groupement azoture à un way groupement aldéhyde. La synthése des azotures de (formyl‐2‐1‐pyrrolyl)‐2‐(et‐3)‐thénoyle‐3(et‐2) est décrite.
Studies on pyrazines. 9 . The facile synthesis of pyrazine 1‐oxides substituted at C‐2 with cyano, methoxycarbonyl and carboxy groups
Authors: Sato Nobuhiro
Published: March 2009

The peroxysulfuric acid oxidation of 2‐cyanopyrazine (1) gave its 1‐oxide 3 (18% yield) and pyrazinecarb‐oxamide (8% yield), while that of methyl pyrazinecarboxylate (2) provided the 1‐ and 4‐oxides in 15 and 7% yields, respectively. On the other hand, pyrazinecarboxylic acid 1‐oxide (7) was prepared by condensation of 2‐methylpyrazine 1‐oxide (8) with benzaldehyde followed by oxidative cleavage (47% overall yield).
Preparation of 7‐substituted pyrrolo [2,3‐d] pyrimidines and 9‐substituted purines as potential antiparasitic agents
Authors: LaMontagne Maurice P. , Smith David C. , Wu Geng‐Shuen
Published: March 2009

A series of six 7‐substituted pyrrolo [2, 3‐d] pyrimidines and two 9‐substituted purines were prepared and evaluated for potential antiparasitic activity. All were inactive against P. berghei in mice. Six of the target compounds were also evaluated for antitrypanosomal activity against T. rhodesiense in mice. All six compounds were also inactive in this screen.
Benzoxazol‐2 (3H)‐one and 1,3,4‐oxadiazol‐2(3H) ‐one derivatives from substituted enaminones and ketoenamines
Authors: Forchiassin M. , Pitacco G. , Risaliti A. , Russo C. , Valentin E.
Published: March 2009

Enaminones and ketoenamines bearing a hydrazine type substituent undergo side chain thermal cyclization, the former into benzoxazol‐2 (3H)‐one derivatives and the latter into 1, 3, 4‐oxadiazol‐2 (3H)‐one derivatives. Factors affecting such reactions are discussed.
Synthesis and carbon‐13 NMR study of 2‐benzyl, 2‐methyl, 2‐aryloctahydropyrrolo [3,4‐c] pyrroles and the 1,2,3,5‐tetrahydropyrrolo [3,4‐c] pyrrole ring system
Authors: Ohnmacht Cyrus J. , Draper Clyde W. , Dedinas Robert F. , Loftus Philip , Wong J. J.
Published: March 2009

2‐Benzyl, 2‐phenyl, 2‐ (3‐methoxyphenyl) and 2‐(3‐trifluoromethylphenyl) octahydropyrrolo[3,4‐c]pyrrole (9a, 9b, 9c, and 9d, respectively) were prepared in five steps from 1‐benzylpyrrole‐3,4‐dicarboxylic acid (2). 2‐Methyloctahydropyrrolo [3,4‐c]pyrrole (9′a) was prepared analogously in six steps from 1‐methylpyrrole‐3,4‐dicarboxylic acid (3). Diborane reduction of 1‐benzyl‐N‐methyl‐1H‐pyrrole‐3,4‐dicarboximide (7′a) and 1, N‐dibenzyl‐1H‐pyrrole‐3,4‐dicarboximide (7a) gave 5‐benzyl‐2‐methyl and 2, 5‐dibenzyl‐1,2,3,5‐tetrahydropyrrolo [3,4‐c]pyrrole (19′ and 19, respectively); the first reported members of the 1,2,3,5‐tetrahydropyrrolo[3,4‐c]pyrrole ring system. A detailed study of the carbon‐13 nmr shifts permitted a complete assignment for all compounds. Mono and disubstituted products produce a systematic effect on the shifts for the bicyclic ring systems which can be readily interpreted in terms of substituent chemical shifts. The effect of protonation at nitrogen is also shown to produce a series of well defined chemical shifts for the octahydropyrrolo [3,4‐c] pyrrole ring system.
Synthesis of some pyridylamino‐1,4‐disubstituted phthalazines
Authors: Bautista Dorothy V. , Bullock Graham , Hartstock Frederick W. , Thompson Laurence K.
Published: March 2009

Two general procedures involving the condensation of phthalonitrile or 1,3‐diiminoisoindoline with various aminopicolines, followed by ring expansion with hydrazine to the corresponding phthalazine are described. Syntheses are reported of 1, 4‐di(3′‐methyl‐2′‐pyridyl) aminophthalazine, 1,4‐di(5′‐methyl‐2′‐pyridyl)aminophthalazine, and 1,4‐di(4′, 6′‐dimethyl‐2′‐pyridyl)aminophthalazine.
Reaction of tetrachloropyrazine with active methylene compounds
Authors: Tong Y. C. , Kerlinger H. O.
Published: March 2009

When tetrachloropyrazine was allowed to react with the anions formed from diethyl malonate and malonitrile, the normal alkylation took place. When the anions from ethyl acetoacetate and N,N‐diethylacetoacetamide were used, alkylation was followed by enolization and ring formation to give furo [2,3‐b] pyrazines. The structure proof and reaction of the furo [2,3‐b] pyrazines are discussed.
Identification of the nitrosation reaction products of alkyl esters of 1,2‐benzisoxazole‐3‐acetic acid by chemical and crystallographic methods
Authors: Giannella Mario , Gualtieri Fulvio , Fedeli Walter , Cerrini Silvio , Gavuzzo Enrico
Published: March 2009

The reaction between methyl or ethyl esters of 1, 2‐benzisoxazole‐3‐acetic acid and iso‐amyl nitrite is reported. The main product is identified as 4‐(2′‐hydroxyphenyl)furazan‐3‐carboxylic acid (4) by chemical and X‐ray crystal structure analyses. The synthesis of esters of E‐ and Z‐α‐(hydroxyimino)‐1, 2‐benzisoxazole‐3‐acetic acid is also reported.
A simple synthesis of 5‐fluorouracil by a novel ring transformation reaction
Authors: Chung Won Keun , Chung Jin Hyun , Watanabe Kyoichi A.
Published: March 2009

A very simple method for the preparation of 5‐fluorouracil (1) from 1,3‐dimethyl‐5‐azauracil (2) by a novel ring transformation reaction is reported.
Synthesis of 6,7‐methylenedioxy‐3,4‐dihydro‐1‐methylbenzothieno[2,3‐c]pyridine
Authors: Ruffin L. D. , Bowlus S. B.
Published: March 2009

Synthesis of the title compound, a potential inhibitor of mouse brain monoamine oxidase, is described. The preparation proceeds in eight steps from 1,3‐benzodioxole in 1.9% overall yield. The novel hydrogenolysis of an aryl thiocyanate to the aryl methyl sulfide is reported.
A convenient synthesis of 1‐methyl‐4‐oxopiṕecolic acid methyl ester
Authors: Essawi M. Y. , Portoghese P. S.
Published: March 2009

An efficient and convenient synthesis of the title compond 1 is described. The approach to the synthesis is based on hydride reduction of the 4‐methoxypyridinium salt 5, followed by acid hydrolysis of the resulting vinyl ether intermediate 6.
Preparation of zwitterionic electron acceptors and donors
Authors: Willner Itamar , Ford William E.
Published: March 2009

The reactions of 4, 4'‐bipyridine and nicotinamide with 1, 3‐propane sultone yields zwitterionic electron acceptors. Reaction of dimethylaminoethyl ferrocene with 1, 3‐propane sultone yields a zwitterionic ferrocene electron donor. The electron acceptors and donor are reduced and oxidized to the respective radical anions and ferrocenyl cation. Dipropyl‐4, 4'‐bipyridinium disulfonate and the ferrocene derivative quench the excited Ru(bipy)32+.
Reactions of 2‐hydroxybenzonitrile with isocyanates
Authors: Petridou‐Fischer J. , Papadopoulos E. P.
Published: March 2009

Triethylamine catalyzes the reaction of 2‐hydroxybenzonitrile (1) with aryl isocyanates to form the corresponding carbamates 2a‐c, as well as the cyclization of the latter compounds to either 4[N‐(N‐arylcarbamoyl)‐imino]‐3‐aryl‐2H‐1,3‐benzoxazin‐2‐ones 4a‐c, or 4‐arylamino‐2H‐1,3‐benzoxazin‐2‐ones 7a‐c, depending on the reaction temperature. Under analogous conditions, the carbamates obtained from 1 and 2‐chloroethyl isocyanate, 3‐chloropropyl isocyanate and ethyl isocyanatoacetate undergo a double cyclization yielding imidazo‐ and pyrimido[1,2‐c|1,3]benzoxazinones 13a,b,17. Upon heating in phenyl ether, compounds 7a‐c, rearrange to 2‐(2‐hydroxyphenyl)‐4(3H)‐quinazolinones 10a‐c.
Syntheses de nouveaux heterocycles pyrroliques: Des thiepino[4,5‐c]‐ et [4,5‐b]pyrroles
Authors: Duflos Jack , Dupas Georges , Quéguiner Guy
Published: March 2009

La réaction des diformyl‐3,4 et −2,3 N méthyl pyrroles (1) et (2) avec des sulfones donne respectivement les dioxydes‐6,6 thiépino[4,5‐c]‐ et [4,5‐6]pyrroles. Nos essais pour condenser les sulfures avec 1 ont conduit au cycle thiépino[4,5‐c]pyrrolique, mais seulement à une benzoannélation avec 2.
Synthesis of a novel indolobenzodiazepine
Authors: Peet Norton P. , Sunder Shyam
Published: March 2009

2‐[(5‐Methyl‐1,3,4‐oxadiazol‐2‐yl)methyl]benzenamine (15) was prepared in four steps from o‐nitrophenyl‐acetic acid, and treated with triethyl orthoformate in an attempt to prepare an oxadiazolobenzodiazepine. However, the resulting product was 13‐(5‐methyl‐1,3,4‐oxadiazol‐2‐yl)‐5H‐indolo[2,1‐b][1,3]benzodiazepine monohydrate (16). Indolobenzodiazepine 16 is the first reported member of a novel ring system. Interesting features of the synthesis of 16 are discussed, including the mechanism of formation from 15.
New oxidative cyclizations of 1,3,4,6‐tetraketones. Synthesis and structure of (Z)‐2‐acyl‐5‐alkyl(aryl)‐1,4‐dioxaspiro[2.4]hept‐5‐en‐7‐ones
Authors: Poje M. , Sikirica M. , Vicković I.
Published: March 2009

Iodosobenzene diacetate oxidation of 1,3,4,6‐tetraketones 1a‐c yielded (Z)‐2‐acyl‐5‐alkyl(aryl)‐1,4‐dioxa‐spiro[2.4]hept‐5‐en‐7‐ones (4a‐c) in addition to 2‐acyl‐6‐alkyl(aryl)‐3‐hydroxy‐4‐pyrones (3a‐c). The structure of new spiro‐heterocycles 4 was inferred from chemical and spectroscopic data, and the stereochemistry was fully defined by a single‐crystal X‐ray analysis. Alternative cyclization pathways can be rationalized as proceeding through carbocation intermediates derived from both forms of the ring‐chain tautomerism of 1,3,4,6‐tetraketones 1.
6‐Iodo‐2‐chloro‐7‐methylpurine
Authors: Mckenzie Thomas C. , Cassity Bernard J.
Published: March 2009

The structure of the compound obtained upon treatment of 2,6‐dichloro‐7‐methylpurine with hydroiodic acid and phosphonium iodide is revised.
Synthesis of new heterocycles. 3,4‐dihydropyrano[2,3,4‐hi]indolizine and derivatives
Authors: Sliwa Henri , Blondeau Dominique , Rydzkowski Richard
Published: March 2009

Interaction of the lithium derivative of 2,3‐dihydro‐4H‐pyrano[3,2‐b]pyridine with the diethyl acetal of bromoacetaldehyde, followed by hydrolysis and subsequent ring closure afforded the novel heterocycle 3,4‐dihydropyrano[2,3,4‐hi]indolizine which was inacessible by the Tschitschibabin method. However, the 2‐phenyl derivative was easily prepared by the Tschitschibabin method.
Synthesis and spectral behavior of 6‐phenyl‐5,6,7,8‐tetrahydro‐4H‐1,3,6‐dioxazocines using NMR
Authors: Nishiyama Tomihiro , Iwasaki Yoshiaki , Yamada Fukiko
Published: March 2009

Heterocyclic compounds of four 6‐phenyl‐5,6,7,8‐tetrahydro‐4H‐1,3,6‐dioxazocines have been synthesized by condensation of the corresponding N,N‐bis(2‐hydroxyethyl)‐ or N,N‐bis(2‐hydroxypropyl)anilines with aldehyde or ketone in the presence of acid. The pmr and cmr spectra of these compounds were recorded to determine their stereochemical structures. On the basis of the chemical shifts due to the γ‐effects, the stereochemical structures are discussed.
Synthesis of ketobemidone precursors via phase‐transfer catalysis
Authors: Cammack Thomas , Reeves Perry C.
Published: March 2009

Hydrochloride salts of N‐substituted‐bis‐(2‐chloroethyl)amines can be condensed with m‐methoxyphenyl‐acetonitrile or 1‐phenyl‐2‐alkanones under phase‐transfer conditions to yield precursors of the powerful analgesic compounds ‐ the ketobemidones.
Furopyridines. IV. Unexpected dimerization of 5‐methyl‐4,5,6,7‐tetrahydrofuro[3,2‐c]‐ and 6‐methyl‐4,5,6,7‐tetrahydrofuro[2,3‐c]pyridine by acidic hydrolysis
Authors: Shiotani Shunsaku , Morita Hiroyuki , Inoue Masatoshi , Ishida Toshimasa , Doi Mitsunobu , In Yasuko
Published: March 2009

Reaction of 5‐methyl‐4,5,6,7‐tetrahydrofuro[3,2‐c]‐ (1) and 6‐methyl‐4,5,6,7‐tetrahydrofuro[2,3‐c]pyridine (2) with hydrochloric acid gave novel dimerized compounds 3a‐d and 4a‐d, respectively. The structures of 3a, 3b, 4a and 4b were determined by spectroscopic method, and 3c, 3d, 4c and 4d by single crystal X‐ray analysis. The reaction courses for the formation of these compounds are proposed.
Nuclear hydroxylated metabolite of fluradoline (2‐fluoro‐11‐[(β‐methylamino)ethylthio]dibenz[b,f]oxepin hydrochloride). Identification and synthesis
Authors: Agnew Marc N. , Rizwaniuk Anastasia , Ong Helen H. , Wichmann J. K.
Published: March 2009

Fluradoline (2‐fluoro‐11‐[β‐(methylamino)ethylthio]dibenz[b,f]oxepin), a novel analgesic with an unique profile, was found to be extensively metabolized in man as well as in other species. One of the major metabolites of this drug appeared to be a nuclear hydroxylated derivative of the parent compound, and the site of enzymatic hydroxylation was established to be C(7) by using high‐field proton nuclear magnetic spectroscopy. This structural assignment was subsequently confirmed by the synthesis of an authentic sample of 2‐fluoro‐7‐hydroxy‐11‐[β‐(methylamino)ethylthio]dibenz[b,f]oxepin (2a).
The crystal and molecular structure of an unexpected product from an attempted hantzsch pyridine synthesis. Imine‐enamine tautomerism
Authors: Natale N. R. , Hope Hakon
Published: March 2009

Hantzsch conditions with N‐benzylamine gave carbocycle 3 rather than a dihydropyridine when isoxazolealdehyde 2 was employed.
Heterocyclen aus α‐nitroolefinen. XI . 1,2‐oxazine aus α‐nitroolefinen und β‐dicarbonylverbindungen
Authors: Boberg Friedrich , Ruhr Maria , Garburg Karl‐Heinz , Garming Alfons
Published: March 2009

Dihydro‐1,2‐oxazine 8 und 1,2‐Oxazine 12 werden aus Nitronsäuren der Addukte aus α‐Nitroolefinen und β‐Dicarbonylverbindungen (6) auf zwei Wegen hergestellt: A) Die Nitronsäuren 6 werden in einer siedenden Lösung von Harnstoff in Ethanol oder Methanol erhitzt. B) Die Nitronsäuren 6 werden mit einer wäßrigen Ammoniumchlorid/Natriumsulfid‐Lösung reduziert. 1H‐NMR‐ und 13C‐NMR‐Untersuchungen beweisen die Konstitutionen. Der Mechanismus wird diskutiert.
Determination of structure and 13C chemical shift assignments of the nitration products of 2‐chloro‐10‐methylphenothiazine. X‐Ray molecular structure of 2‐chloro‐7‐nitro‐10‐methylphenothiazine 5‐oxide
Authors: Jovanovic Misa V. , Biehl Edward R. , De Meester Patrice , Chu Shirley S. C.
Published: March 2009

Nitration of 2‐chloro‐10‐methylphenothiazine, 1, yields two mono‐nitro compounds identified as sulfoxide 2 and sulfone 3. The nmr analyses of the 13C spectra of 2 and 3 establish unequivocally that in both compounds substitution has occurred at the seven position. This is supported by the X‐ray crystal structure of one of the compounds 2‐chloro‐7‐nitro‐10‐methylphenothiazine 5‐oxide, 2, which also shows that the sulfoxide group is in the “pseudo‐axial” configuration. Crystals of 2 are monoclinic, space group P21/n, a = 11.606(4), b = 13.970(4)Å, c = 9.837(2), β = 127.49(2)° and Z = 4. The structure has been refined by full‐matrix least‐squares to R = 0.033 and Rw = 0.035, using 1704 observed reflections.
Synthesis and fluorescence of N‐substituted‐1,8‐naphthalimides
Authors: Middleton Richard W. , Parrick John , Clarke Eric D. , Wardman Peter
Published: March 2009

A number of novel N‐substituted‐1,8‐naphthalimides have been prepared and their fluorescence yields measured in water at pH 7.4. The type of substitutent and the substitution pattern on the naphthalimide nucleus produce markedly different fluorescence yields, (quantum efficiencies, ø varying from ø = 0‐0037 for N‐(3‐N'‐morpholino‐1‐propyl)‐4‐amino‐3‐methoxy‐1,8‐naphthalirnide (7) to ø = 0–77 for N‐(3‐bromopropyl)‐4‐acetamido‐1,8‐naphthalimide (31).
Studies on pyrazines. 14 The syntheses of 2,5‐dihydroxypyrazines and their derivatives
Authors: Adachi Jiro , Sato Nobuhiro
Published: March 2009

Reaction of phenylglycinamide (1c) with ethyl benzoylformate (2c) in the presence of refluxing ethanolic sodium ethoxide gave 2,5‐dihydroxy‐3,6‐diphenylpyrazine (3i) in 19% yield. This synthetic method, however, was limited to the preparation of 3i. On the other hand, α‐aminoamides 1 condensed with α‐ketoesters 2 to give the intermediates 5, which were also prepared by condensation of 1 with α‐ketalesters 6, followed by hydrolysis of the ketal moeity. Cyclization of 5 with refluxing methanolic sodium methoxide gave only disubstituted 2,5‐dihydroxypyrazines 3. Acetylation of 5 with refluxing acetic anhydride/acetic acid led to direct formation of 2,5‐diacetoxypyrazines 9. Similarly, compounds 5 could be converted into 2,5‐dichloropyrazines 4.
Bridged isocytosine‐adenosine compounds: Synthesis and antibacterial evaluation
Authors: Lever O. William , Vestal B. Randall
Published: March 2009

In an approach to novel antibacterial agents, we synthesized a series of 5‐nitrosoisocytosines in which a 6‐alkylamino substituent is bridged, through an amide linkage at the terminus of the alkyl chain, to the 5′‐position of a 5′‐deoxyadenosine moiety. A corresponding series of 5‐nitro analogues were also prepared. None of the bridged compounds showed significant antibacterial activity.
Determination of the preferred tautomeric form of 4‐nitrohistidine
Authors: Pedroso Enrique , Grandas Anna , Ludevid Ma. Dolors , Giralt Ernest
Published: March 2009

Spectrophotometric pKa determinations of methyl derivatives of Nα‐acetyl‐4‐nitrohistidine methyl ester 1 have been used to determine the position of the tautomeric equilibrium of 1. The N1‐H tautomer is the predominant form with an equilibrium constant KT of 48.

The conclusion is supported qualitatively by the study of 1H‐nmr and 13C‐nmr chemical shifts of the imidazole ring atoms and their changes from neutral to acidic media.
Syntheses of substituted pyrazolo[3,4‐b]quinolines, 3,4‐dihydro‐4‐oxopyrimido[4′,5′:4,5]theino[2,3‐b]quinoline and pyrido[1′,2′:1,2]pyrimido[4,5‐b]quinoline
Authors: Neelima  , Bhat Balkrishen , Bhaduri Amiya Prasad
Published: March 2009

Syntheses of substituted pyrazolo[3,4‐b]quinolines, 3,4‐dihydro‐4‐oxopyriraido[4′,5′:4,5]theino[2,3‐b]quinoline and 12‐phenylpyrido[1′,2′:1,2[pyrimido[4,5‐b]quinoline are described.
Synthesis of 2‐ and 3‐substituted‐1,2,3,4‐tetrahydrodibenzo[f,h]isoquinolines
Authors: Grande Mercedes T. , Trigo Gregorio G. , Söllhuber Mónica M.
Published: March 2009

Some 2‐ and 3‐substituted‐1,2,3,4‐tetrahydrodibenzo[f,h]isoquinolines were prepared by a synthetic scheme involving a selective Borch reduction of an amide to the corresponding amine and a Friedel‐Crafts cyclization to obtain the dibenzo[f,h]isoquinoline system. The title compounds, which have a similarity to the cell growth inhibitory alkaloid cryptopleurine, failed to exhibit significant protein synthesis inhibitory activity.
Base‐Catalyzed cyclization of N‐propargylamides to oxazoles
Authors: Nilsson Björn M. , Hacksell Uli
Published: March 2009

The base‐catalyzed cyclization of some N‐propargylamides to oxazoles has been studied in the presence of sodium hydride and potassium carbonate. The α‐arylsubstituted propargylamides 1c‐d (Ar = p‐OMeC6H4 (1c), C6H5 (1d), and p‐O2NC6H4 (1e)) cyclized with markedly higher rates (1e > 1d > 1c) than the unsubstituted and α‐methyl substituted propargylamides 1a and 1b. A 1H nmr spectroscopic experiment demonstrated the presence of an allenic intermediate in the potassium carbonate‐catalyzed ring closure of 1e. The observed rank order of reactivities correlates well with the acidities of the respective propargylic hydrogens of the amides and with the ability of the ring closed intermediates to stabilize an oxazole anion. The results demonstrate that the base‐catalyzed formation of oxazoles from propargylamides may proceed via an allenic intermediate.
Synthesis, structural and conformational study of 4‐α‐(or β)‐p‐chlorobenzoyloxy‐1‐azaadamantane hydrochloride
Authors: Fernandez M. J. , Galvez E. , Lorente A. , Soler J. A. , Florencio F. , Sanz J.
Published: March 2009

4‐α‐(or β)‐p‐Chlorobenzoyloxy‐1‐azaadamantane hydrochloride have been synthesized and studied by 1H and 13C nmr spectroscopy, and the crystal structure of the α‐epimer has been determined by X‐ray diffraction. Each ring of the adamantane cage system is a nearly perfect chair, the substituted cyclohexane and piperidine rings, in endo and exo position respectively, having the biggest deviation. From the 1H and 13C nmr data, several stereoelectronic effects have been deduced.
Cycloaddition reactions of cephalosporin compounds. XI. 1,3‐dipolar cycloaddition reaction of an exo‐2‐methylenecephem with diphenyldiazomethane
Authors: Pitlik János , Jászberényi J. Csaba
Published: March 2009

In the 1,3‐dipolar cycloaddition reaction of the exo‐2‐methylenecephem 6 with diphenyldiazomethane the initially formed pyrazolines decompose and spirocyclopropylcephalosporin formation takes place. The structure elucidation with 1H, 13C, ASIS and NOE nmr methods is also described.
Electron impact mass spectrometry of 2‐(methoxycarbonylmethyl)‐2‐phenyl‐1,3‐benzoxathiole and 2‐acetonyl‐2‐phenyl‐1,3‐benzoxathiole
Authors: Prison Giampietro , Traldi Pietro , Cocco Maria Teresa , Podda Gianni
Published: March 2009

The electron impact mass spectrometric behaviour of 2‐(methoxycarbonylmethyl)‐2‐phenyl‐1,3‐benzoxa‐thiole 3a and 2‐acetonyl‐2‐phenyl‐1,3‐benzoxathiole 3b has been studied in detail. The structures of the more interesting fragment ions have been confirmed with the aid of accurate mass measurements, linked scans and collisional activation experiments. In addition to the ionic species already described in the general fragmentation pattern of 1,3‐benzoxathiole derivatives, other fragments arising from the interaction of the carboxy‐containing chain with the sulfur atom of these compounds have been observed and evidence presented.
Synthesis of new gramine‐type analogs of CC‐1065
Authors: Rajeswari Sundaramoorthi , Adesomoju Akinbo A. , Cava Michael P.
Published: March 2009

Preparation of two new analogs 5 and 6 of the antitumor antibiotic CC‐1065 1 are described. These compounds represent structural modifications of the active analogs 3 and 2 respectively, in which the dienone A‐unit has been replaced by the tricyclic achiral gramine unit 4. Modest cytotoxicity was exhibited by compounds 5 and 6.
Synthesis of new alkyl‐ alkenyloxy‐ and hydroxy‐substituted diaza‐crown compounds
Authors: Bradshaw Jerald S. , Krakowiak Krzysztof E. , Izatt Reed M.
Published: March 2009

New diaza‐crown compounds with the macro ring nitrogen atoms situated in the 1, 4‐, 1, 7‐ and 1, 10‐positions have been prepared. All of the new macrocycles contain alkyl groups on the nitrogen atoms and a functional group substituent in the form of either an allyloxymethyl, allyloxy or hydroxy group on one of the macro ring carbon atoms. A 1, 4‐diaza‐crown attached to silica gel removes Hg(II) ions from an aqueous mixture of Hg(II), Cd(II) and Zn(II) ions.
Studies on heterocyclic compounds. VII. Syntheses of novel furo[2, 3‐b]chromones
Authors: Kuo Sheng‐Chu , Wu Jiin‐Sheng , Huang Li‐Jiau , Wu Chun‐Hsiung , Huang Shun‐Chueh , Chou Teh‐Chang
Published: March 2009

Furo[2, 3‐b]chromone (1a) was conveniently prepared by the PPE‐promoted cyclization of 5‐(2′‐carboxy‐phenoxy)furan‐2‐carboxylic acid (8) which was made from methyl salicylate and ethyl 5‐nitrofuran‐2‐carboxyl‐ate. Furo[2, 3‐b]chromon‐2‐acrylic acid (13) was obtained by a similar cyclization. Direct acylation of 1a afforded 2‐acetylfuro[2, 3‐b]chromone (10). Several derivatives of furo[2, 3‐b]chromone were found to display activity in the rat passive cutaneous anaphylaxis (PGA) test for antiallergic activity.
Hydrogenation of substituted 1‐arylisoquinolin‐3(2H)‐ones to 5, 6, 7, 8‐tetrahydro‐ and 1, 4‐dihydroisoquinolin‐3(2H)‐ones
Authors: Hazai László , Deák Gyula , Tóth Gábor , Tamás József
Published: March 2009

Catalytic hydrogenation of variously substituted 1‐arylisoquinolin‐3(2H)‐ones 1 gave, depending on the substituents, 5, 6, 7, 8‐tetrahydroisoquinolin‐3(2H)‐ones (2) and/or the corresponding 1, 4‐dihydro derivatives 3. Saturation of the compounds fused with benzene ring furnished as the main products the 9, 10‐dihydro‐ (4 and 5) and 5, 6‐dihydroisoquinolin‐3(2H)‐ones (6) in the case of benzo[f] and benzo[h] anellation, respectively, in addition to the 1, 4‐dihydro compounds detected or isolated as by‐products.
Tautomerism in barbituric and thiobarbituric acids
Authors: Millefiori Salvatore , Millefiori Arcangelo
Published: March 2009

The molecular geometry of barbituric and thiobarbituric acid tautomers have been fully optimized using the AMI method in order to estimate the relative energies of the tautomers. The results are in agreement with available experimental data and indicate that in the vapour the barbiturate ring is essentially planar. In both unsubstituted compounds the trioxo structure is found to be the most stable one, in agreement with experimental findings in the solid. Tautomeric equilibria are sensitive to phase change and to substitution at the C5 position. On passing from the vapour to the water the population of the most polar structure increases, although the order of stability remains unchanged and only for the Br and I derivatives it can be suggested the coexistence of two forms in solution. The substitution at C5 does not alter the order of stability except for the 5‐nitro derivatives where the dioxo form predominates, in agreement with experimental results in the solid. Electron affinities and ionization potentials of the tautomers have been evaluated and briefly discussed. It is suggested that gas‐phase uv photoelectron spectroscopy should be able in analysing the tautomeric equilibria of barbituric and thiobarbituric acids in the vapour.