bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Al Content on Hydrogen Storage Properties of Amorphous Mg1-xAlxNi (x=0, 0.1, 0.2, 0.3) Alloy
Authors: Wang Jing Feng , Ding Pei Dao , Gao Shan , Pan Fu Sheng , Tang Aitao
Published: March 2009

In this paper，the influence of adding Al on the discharge capacity and cycle stability of amorphous MgNi-based hydrogen storage alloys were investigated. Amorphous Mg1-xAlxNi (x=0, 0.1, 0.2, 0.3) alloy powder was prepared successfully by mechanical alloying (MA). X-ray diffraction (XRD) results show that after ball milling with 15h, MgNi alloy formed completely amorphous phase. But for Mg1-xAlxNi (x=0.1, 0.2, 0.3) alloy, it took 30h. It can be concluded that Al partial substituting Mg would decrease the amorphous phase forming ability of Mg-Ni Based Alloy. The discharge capacities and cycle stabilities of these alloys were tested. Compared with amorphous MgNi alloy, the discharge capacities of Mg1-xAlxNi (x=0.1, 0.2, 0.3) alloy were decreased slightly, but the cycle stabilities were significantly enhanced. Mg0.9Al0.1Ni alloy showed the largest discharge capacity and Mg0.8Al0.2Ni alloy showed the best cycle stability. Over all, ternary Mg0.8Al0.1Ni alloy showed the best synthesis properties.
Study on Expansion of Cement-Based Material with Addition of Magnesium Oxide
Authors: Chen Ke , Yang Chang Hui , Wu Fang , Ye Jian Xiong , Zhao Shu Ang , Xiang Xiao Bin
Published: March 2009

In this paper, the influence of the types and addition dose of MgO expanding agent and the age of cement on expansion value and expansion performance of cement based material added with MgO expanding agent was systematically studied.The expansion characteristics of cement based material added with MgO expanding agent or calcium sulphoaluminate expanding agent were compared. The expansion of such material increases with the addition dose of MgO expanding agent and cement mortar age. During the test period, the expansion of cement based material increases continuously. The light-burned MgO expanding agent modified by CaO expanding agent is able to increase the 28d expansion of such material effectively. The temperature of calcination for the heavy-burned MgO expanding agent is higher than that of light-burned one, thus the heavy-burned MgO expanding agent has a rather dense structure with slow hydration rate and gives a small expansion of the cement based material at early age, showing an obvious expansion delay. The calcium sulphoaluminate expanding agent gives most expansion of the material in the early 28d and there is small expansion at middle and later age of the material.
Strain Rate Evolution in Aluminium Alloy Measured by ESPI during Tensile Test
Authors: Petit Johann , Montay Guillaume , François Manuel
Published: March 2009

The original and significant achievement of this work is to analyse strain rate field in aluminium alloy sheets during micro tensile test. In-plane Electronic Speckle Pattern Interferometry is used to follow the evolution of the local strain in real time. This paper is based on the detection of the localization on a relatively small area of the analysed specimen: less than 5mm × 4mm area. Moreover the speed of the tensile machine is very low, 0.2 to 0.1µm/s.
The phase shifting technique is used to obtain the fringes representative of the material displacement. We can therefore get a very good accuracy in the material displacement.
A heterogeneity in strain rate field can be noticed from a deformation stage which doesn’t coincide with the one calculated by the classic Considère’s criterion (dF=0) for the diffuse neck initiation (or plastic instability). We also show, the moment when one of the two slip bands systems becomes predominant, and even only one band continues to exist, this occurring widely before fracture. Finally, the fracture of the specimen occurs across this remaining band.
The total strain is measured with a second camera, in white light, and is correlated together with the strain rate field to study the localization.
Influence of Growth Rate and C/Si-Ratio on the Formation of Point and Extended Defects in 4H-SiC Homoepitaxial Layers Investigated by DLTS
Authors: Zippelius Bernd , Krieger M. , Weber Heiko B. , Pensl Gerhard , Kallinger Birgit , Friedrich Jochen , Thomas Bernd
Published: March 2009

4H-SiC epilayers are homoepitaxially grown on 4H-SiC substrates with different C/Si-ratios and different growth rates by the chemical vapour deposition method. DLTS investigations are applied in order to trace energetically deep states of electrically active point defects and extended defects, which may act as the source for the degradation of electronic devices. In addition, the dependence of the DLTS signal heights on the filling pulse length is studied.
Comparison of 4H-SiC MOSFETs on (0001), (000-1) and (11-20) Oriented Substrates
Authors: Naik Harsh , Tang K. , Marron T. , Chow T. Paul , Fronheiser Jody
Published: March 2009

The effect of using different orientations of 4H-SiC substrates on the performance of 4H-SiC MOSFETs has been evaluated. Three sets of samples with (0001), (000-1) and (11-20) oriented SiC substrates were used to fabricate the MOSFETs, with a gate oxide process consisting of a low- temperature deposited oxide followed by NO anneal at 1175°C for 2hrs. Various device parameters, particularly threshold voltage, subthreshold slope, field-effect mobility, inversion sheet carrier concentration and Hall mobility have been extracted. Temperature characterization up to 225°C was also performed.
The male genital tract of Chaoboridae (Diptera: Culicomorpha)
Authors: Borkent Art , Borkent Christopher J. , Sinclair Bradley J.
Published: March 2009

The male genital tract of Chaoboridae, represented by Eucorethra underwoodi Underwood, Mochlonyx velutinus (Ruthe), and Chaoborus trivittatus (Loew), is described for the first time. All genera have paired accessory glands that are attached anteriorly to the vasa deferentia or the base of the testes, a feature that is proposed as a synapomorphy of Chaoboridae + Culicidae. Mochlonyx Loew and Chaoborus Lichenstein have distinctive pigment cells covering their testes and a portion of the vasa deferentia. The simplified male genital tract of Corethrellidae + Chaoboridae + Culicidae is correlated with the virtually unique abrupt and permanent 180° rotation of the male genitalia between segments 7 and 8. In taxa with an accessory-gland complex, the male genitalia are rotated in a more gradual manner, often during copulation.
Shallow Water Flow Prediction From Seismic Analysis of Multicomponent Seismic Data
Authors: Huffman Alan R. , Castagna John P.
Published: March 2009

Introduction

Shallow Water Flows (SWF) are recognized as one of the primary hazards todeepwater drilling operations in the Gulf of Mexico. These hazards have costthe oil industry an estimated $200MM in the last few years. Future occurrenceshave the potential to result in well failures and significant discharges ofsubsurface fluids into the ocean. At present, most operators choose to drillthrough these hazards with a modest investment in identification beforedrilling, and mitigate the hazard at significant expense if one is encountered. The occurrence of SWF has been identified as one of the top five challengesbeing faced in deepwater exploration and production. According to a report from Fugro Geoservices, Inc. approximately 70% of all deepwater wells haveexperienced SWF.

A method for pre-drill delineation of sands that are close to failure, andthus likely to exhibit shallow water flows, would be most advantageous inselecting optimal drilling locations and in developing cost-effective wellplans. The current method of identifying SWF involves pre-drill hazard studiesutilizing conventional and high-resolution seismic data to identify the zonesthat might produce SWF. The high incidence of SWF mitigation events indeepwater wells shows that the existing techniques do not provide the neededresolution or accuracy to prevent SWF.

At present, no robust seismic method for accurately identifying andcharacterizing these hazards exists. Operators do not have the option to avoidthe hazard instead of mitigating the problem after it has started. A newseismic analysis method is required that will permit operators to avoid thehazard and decrease the risk of well failures before the well is drilled.

An accurate understanding of the physical properties and deformationalbehavior of shallow water flow (SWF) sands is essential to thecharacterization, prediction and interpretation of these stratigraphic unitsusing seismic data. To date, there have been very few core and log formationevaluation measurements taken in these shallow intervals because they are notof economic interest. The purpose of this paper is to address what is currentlyknown about the physical properties and rock mechanics of these veryunconsolidated formations, and to demonstrate how these properties can be usedto identify and characterize SWF intervals pre-drill.
Rice
Authors: Emani Chandrakanth , Jiang Yiming , Hall Timothy C. , Miro Berta , Kohli Ajay
Published: March 2009

Rice serves as the principal source of nourishment for over half of the global population. The year 2004 was declared as the international year of rice by the Food and Agricultural Organization, to heighten awareness of this crop in combating global poverty and malnutrition. The present review is a comprehensive account of this model monocot crop tracing its history, botanical descriptions, and the research work in breeding and biotechnology. An exhaustive illustrative account of all the important milestones in plant breeding, particle bombardment,Agrobacterium‐mediated transformation, and genomics has been provided, with a focus on other important aspects such as transgene silencing, biosafety regulations of transgenic plants, and the global consequences of rice biotechnology research.
Sugarcane
Authors: Brumbley Stevens M. , Snyman Sandy J. , Gnanasambandam Annathurai , Joyce Priya , Hermann Scott R. , da Silva Jorge A.G. , McQualter Richard B. , Wang Ming‐Li , Egan Brian T. , Paterson Andrew H. , Albert Henrick H. , Moore Paul H.
Published: March 2009

As more than 70% of the sugar harvested for human consumption is derived from sugarcane, improving sucrose content, biomass yield, and resistance to pests and diseases remains an important focus of traditional breeding programmes. In addition, genetic engineering research has supported the introduction of specific traits and facilitated further understanding of complex physiological pathways in the plant. Transgenesis has allowed diversification of output traits so that a range of sugars, biopolymers, neutraceuticals, industrial enzymes, and pharmaceuticals can be produced by the plant. Sugarcane is considered as a critical component of our bioenergy future and is currently a major feedstock for ethanol production. Significant advances in associating putative biological functions to sugarcane genes have been achieved by the Brazilian SUCEST project. Future genetic improvement of sugarcane will rely on a better understanding of metabolic control and flux, cellular compartmentation and availability of metabolites, and the ability to identify potential and crucial targets for genetic engineering.
Tobacco
Authors: Dhingra Amit , James Victoria A. , Koop Hans U. , Mok Machteld C. , De Paepe Rosine , Gallo Maria , Folta Kevin M.
Published: March 2009

January of 1983 was a turning point for plant biotechnology when tobacco was immortalized as a surrogate biological system for testing gene function at a conference on “Advances in Gene Technology: Molecular Genetics of Plants and Animals” hosted by the Miami Winter Symposia series. AlthoughArabidopsishas now become the system of choice for nuclear gene integration due to the ease of transformation and a short generation cycle, tobacco remains the only established system for plastid transformation. This review summarizes the use of tobacco in dissecting plant biology concepts pertaining to the three important compartments of the cell that harbor genetic material within them. Recent studies inN. benthamianahave brought the genus back to the limelight as an outstanding system for transient protein expression. Overall, this chapter also brings out the advantages and limitations of tobacco as a system for discovery in plant biology. As a nonfood and nonfeed crop tobacco retains a remarkable potential for use as a biofactory. Ironically, this genus with a notorious health reputation may prove to be indispensable for the production of medically relevant compounds.
Sex differences in humeral bilateral asymmetry in two hunter‐gatherer populations: California Amerinds and British Columbian Amerinds
Authors: Weiss Elizabeth
Published: March 2009

This study uses two prehistoric Amerindian populations of hunter‐gatherer subsistence patterns to determine whether levels of sexual dimorphism in humeral bilateral cross‐sectional asymmetry are related to sex‐specific differences in activities among these populations. Results confirmed that males of the California Amerind population who engaged in the more unimanual activities of spear hunting and warfare were more asymmetrical than were their female counterparts who engaged in the more bimanual activities of grinding acorns. California Amerind males were also more asymmetrical than British Columbian Amerind males who rowed (using both arms) extensively. Sex differences within British Columbian Amerinds were not statistically significant, nor were female differences between populations. In general, levels of humeral asymmetry appear to be more dependent on sex and population‐specific behaviors rather than broad subsistence patterns. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.
p21WAF1/CIP1 and cancer: A shifting paradigm?
Authors: Gartel Andrei L.
Published: March 2009

The cyclin‐dependent kinase inhibitor p21WAF1/CIP1 is a key mediator of p53‐dependent cell cycle arrest and may play the role of a tumor suppressor in cancer. However, it has been shown that p21 may also act as an oncogene, because it inhibits apoptosis and may promote cell proliferation in some tumors. These data point out to “antagonistic duality” of p21, because it possesses anticancer and procancer properties at the same time. New data suggest that more and more proteins also may play contradictory roles in cancer thus challenging current paradigm of established oncogenes and tumor suppressors. © 2009 International Union of Biochemistry and Molecular Biology, Inc.
A practical near constant bandwidth amplifier
Authors: Maundy Brent , Gift Stephan , Westwick David
Published: March 2009

This paper presents a simple near constant bandwidth amplifier constructed from two operational amplifiers. The near constant bandwidth is obtained by reducing the normally high input impedance of the opamp via local and overall feedback. Experimental results obtained using identical opamps and different opamps verify the expected theoretical results. Copyright © 2009 John Wiley & Sons, Ltd.
Flavonoid consumption and esophageal cancer among black and white men in the United States
Authors: Bobe Gerd , Peterson Julia J. , Gridley Gloria , Hyer Marianne , Dwyer Johanna T. , Brown Linda Morris
Published: March 2009

Flavonoids and proanthocyanidins are bioactive polyphenolic components of fruits and vegetables that may account for part of the protective effect of raw fruit and vegetable consumption in esophageal cancer. We studied the relationship between esophageal cancer and dietary proanthocyanidins, flavonoids and flavonoid subclasses (anthocyanidins, flavan‐3‐ols, flavanones, flavones, flavonols and isoflavonoids) using recently developed USDA and Tufts flavonoid and proanthocyanidin databases. The study was a population‐based, case–control analysis of 161 white men with esophageal adenocarcinoma (EAC), 114 white and 218 black men with esophageal squamous cell carcinoma (ESCC) and 678 white and 557 black male controls who lived in 3 areas of the United States. Neither total flavonoid nor proanthocyanidin intake was associated with EAC and ESCC in either white or black men. In white men, inverse associations were observed between anthocyanidin intake and EAC (4th vs. 1st quartile odds ratio [OR], 0.47, 95% confidence interval [CI], 0.24–0.91; ptrend = 0.04) and between isoflavonoid intake and ESCC (4th vs. 1st quartile OR, 0.43, 95% CI, 0.20–0.93; ptrend = 0.01). None of the associations remained significant after adjusting for dietary fiber, which is strongly correlated with flavonoid consumption. We conclude that total flavonoids and proanthocyanidins do not have strong protective effects in either EAC or ESCC. Some protective effects were evident in flavonoid subclasses and population subgroups. In white men, foods rich in anthocyanidins may have chemopreventive effects in EAC and those rich in isoflavonoids may do so in ESCC. © 2009 UICC
Chondrogenic differentiation of mesenchymal stem cells embedded in a scaffold by long‐term release of TGF‐β3 complexed with chondroitin sulfate
Authors: Park Ji Sun , Yang Hyun Jung , Woo Dae Gyun , Yang Han Na , Na Kun , Park Keun‐Hong
Published: March 2009

In this study, mesenchymal stem cells (MSCs) embedded in biodegradable and water‐swollen, elastic block copolymer scaffolds were assessed for MSC chondrogenesis. To determine the optimal conditions for chondrogenesis of the embedded rMSCs, transforming growth factor‐β3 (TGF‐β3) was physically conjugated with chondroitin sulfate (CS) and mixed into scaffolds, which were subsequently evaluated for the differentiation of transplanted rMSCs. In determination of CS‐bound growth factors for chondrogenesis, scaffold mixed with rMSCs and TGF‐β3 was then tested by growth factor release profiles, confocal laser microscopy, RT‐PCR analysis, real time‐QPCR, and histology. The results of several different analyses of the transplanted rMSCs embedded in the scaffolds showed that rMSCs coupled with a CS‐bound TGF‐β3 encapsulated scaffold evidenced superior cartilage tissue formation as measured by an assay of specific gene and protein expression. Moreover, the scaffold exhibited more rapid and more distinct morphology of differentiated rMSCs than was observed with other scaffolds, as determined by histology and immunochemical histology analysis. These results indicate that the elastic block copolymer scaffolds combined with a CS‐bound TGF‐β3 should prove very suitable matrix for cell‐based cartilage tissue engineering. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Long term in vivo degradation and tissue response to photo‐cross‐linked elastomers prepared from star‐shaped prepolymers of poly(ε‐caprolactone‐co‐D,L‐lactide)
Authors: Chapanian Rafi , Tse Man Y. , Pang Stephen C. , Amsden Brian G.
Published: March 2009

Long term in vivo degradation, and tissue response to, cylindrical elastomers made of photo‐cross‐linked star‐poly(ε‐caprolactone‐co‐D,L‐lactide) triacrylate were investigated through subcutaneous implantation in rats. The elastomers were prepared via UV initiated crosslinking of prepolymers of equimolar amounts of monomers; a high crosslink density elastomer (ELAST 1250) was prepared from a prepolymer of 1250 Da and a low crosslink density elastomer (ELAST 7800) was prepared from a prepolymer of 7800 Da. The elastomers were characterized using cross‐polarization magic angle spinning solid state 13C NMR and attenuated total reflectance fourier transform infrared spectroscopy. The progress of the in vivo degradation process was followed by employing SEM, uniaxial tensile, mass loss, water uptake, and sol content measurements. The rate of in vivo degradation was faster than the rate of in vitro degradation for both ELAST 1250 and ELAST 7800. Long term in vivo degradation studies indicated that both elastomers undergo bulk hydrolysis along with surface erosion occurring due to the physiological environment. In the case of low cross‐link density elastomers, the onset of mass loss was accompanied with an increase in both water uptake and sol content, whereas, in the case of high crosslink density elastomers, only the water uptake increased. This degradation pattern was due to crazing of the high crosslink density elastomers. ELAST 7800 cylinders were totally degraded, and ELAST 1250 cylinders had lost 80% of their mass, within 30 weeks. Aminor host reaction with minimal vascularity and inflammation was invoked, with a milder tissue response observed with more highly crosslinked cylinders. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Evaluation of self‐expandable, FK506‐coated, covered stents in canine animal model
Authors: Sato Sachiko , Nakayama Yasuhide , Matsuhashi Toshio , Seiji Kazumasa , Matsunaga Kenichi , Takasawa Chiaki , Ishibashi Tadashi , Zhou Yue‐Min , Ishibashi‐Ueda Hatsue , Okamoto Yoshihiro , Asano Hiroyuki , Takahashi Shoki
Published: March 2009

This study aimed to evaluate whether drug coating of the recently developed covered SENDAI stents—self‐expandable stents covered with segmented polyurethane (SPU) films—reduces neointimal thickening in animal model. FK506, which is one of the most effective immunosuppressants, was used. Bare stents; non‐coated, covered stents; and FK506‐coated, covered stents were placed bilaterally in the external iliac arteries of beagle dogs. After 1‐month observation period, angiography did not show significant stent‐induced stenosis. Histological evaluation revealed a completely endothelialized intravascular lumen and the absence of thrombus formation. The area of the intimal thickening induced by the FK506‐coated stents was significantly smaller than that induced by the non‐coated stents, whereas it was larger in the case of both the covered stents than that in the case of the bare stent. In conclusion, FK506 treatment of the self‐expandable, covered stents was confirmed to effectively inhibit intimal thickening, although the SPU film used for covering functioned as a drug carrier in addition to a scaffold for intimal formation. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009
Bone responses to rough titanium implants coated with biomimetic Ca‐P in rabbit tibia
Authors: He Fuming , Yang Guoli , Wang Xiaoxiang , Zhao Shifang
Published: March 2009

A new technique to biomimetic deposition calcium phosphate (BDCaP) coating onto rough titanium substrates has been developed recently. This biomimetic deposition technique seems to be promising. It appears to have some advantages such as an inexpensive and simple set‐up, and the possibility to synthesize layers with a defined surface morphology. The aim of this study was to examine the bone responses to BDCaP‐coated implants in a rabbit model. Thirty one implants (16 BDCaP and 15 rough) were inserted into both tibia of 15 rabbits. After 2, 4, and 8 weeks following the implantation, the tibias were retrieved and prepared for histological evaluation. After 2 weeks, BDCaP‐coated implant showed more bone ingrowth inside threads than the rough implants in medullary region (31.43% vs. 24.38%). Histological and quantitative histomorphometrical measurements demonstrated no more bone ingrowth and bone‐implant contact for coated implant as compared with uncoated implant in cortical region at all experiment periods. From the histological viewpoint, the BDCaP coating did not have any positive effect on new bone formation. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009
Synthesis of some 4‐carboxy‐3‐ and 5‐(2‐hydroxyalkyl)pyrazole lactone derivatives
Authors: Gelin Suzanne , Chantegrel Bernard , Deshayes Christian
Published: March 2009

The synthesis and biological activities of some 4‐oxo‐1‐or‐2‐substituted 1H‐or‐2H‐pyrano[4,3‐c]pyrazole derivatives are described.
Diphenyl cyanocarbonimidate. A versatile synthon for the construction of heterocyclic systems
Authors: Webb R. Lee , Labaw Clifford S.
Published: March 2009

A simple high yield synthesis of diphenyl cyanocarbonimidate is reported. This synthon may be used to prepare functionalized benzimidazoles, benzoxazoles and triazoles in good yield under mild conditions.
Selenium heterocycles. XXXV . Synthesis and pyrrolysis of aryloxy‐, arylthio‐, and arylseleno‐1,2,3‐selenadiazoles
Authors: Shafiee A. , Toghraie S. , Aria F. , Mortezaei‐Zandjani G.
Published: March 2009

A series of 4‐substituted‐5‐arylthio‐1,2,3‐selenadiazoles, 4‐substituted‐5‐arylseleno‐1,2,3‐selenadiazoles and 4‐aryloxymethyl‐1,2,3‐selenadiazoles were synthesized. Pyrrolysis of these compounds afforded the corresponding acetylenes XI, XIII (X = S, Se) and XII, respectively. Oxidation of 4‐substituted‐5‐arylthio‐1,2,3‐selenadiazoles (XIV) with m‐chloroperbenzoic acid gave 4‐substituted‐5‐arylsulfinyl‐1,2,3‐selenadiazoles (XV) and 4‐substituted‐5‐arylsulfonyl‐1,2,3‐selenadiazoles (XVI).
A New Synthesis of 4‐(Alkyl)aminopteridines
Authors: Hara Hiroshi , Van Plas Henk C. Der
Published: March 2009

On treatment of pteridine with potassium permanganate in liquid ammonia, 4‐aminopteridine is obtained in good yield. The C4 σ adduct 4‐amino‐3,4‐dihydropteridine is the intermediate species. Similarly, 2‐chloropteridine undergoes amination at C4, yielding 4‐amino‐2‐chloropteridine; thus no replacement of the chloro atom occurs. By this amination‐oxidation procedure 4‐ethylaminopteridine and its 2‐chloro derivatives are also easily obtained.
A novel synthesis of 1H‐pyrrole‐2,3,4,5‐tetracarboxylates
Authors: Zaima Tadataka , Matsunaga Yoshiharu , Mitsuhashi Keiryo
Published: March 2009

A novel and convenient synthesis of 1H ‐pyrrole‐2,3,4,5‐tetracarboxylates is described. Photocyclization of 1,1′‐bis(methoxycarbonyl)divinylamine with acetylenedicarboxylates gave 7‐azabicyclo[2.2.1]hept‐2‐ene‐1,2,3,4‐tetracarboxylates 2a‐i, which on melting split ethylene off to yield 1H‐pyrrole‐2,3,4,5‐tetracarboxylates 3a‐i quantitatively.
On the amination of 3‐nitro‐1,8‐naphthyridines
Authors: Wozniak Marian , Van Der Plas Henk C. , Van Veldhuizen Beb
Published: March 2009

A number of 3‐nitro‐2‐X‐1,8‐naphthyridines (X = H,Cl,NH2,OEt) were successfully aminated into the corresponding 4‐amino‐3‐nitro‐2‐X‐naphthyridines, using liquid ammonia and potassium permanganate as reagents. 4‐Amino‐1,4‐dihydro‐3‐nitro‐2‐X‐1,8‐naphthyridines are the actual species being oxidized by the potassium permanganate; their existence has been by 1H nmr spectroscopy.
Chemistry of 5‐pyrimidinecarboxaldehydes
Authors: Bell Lawrence , McGuire H. Michael , Freeman G. Andrew
Published: March 2009

Selective hydrolysis of 2‐amino‐4,6‐dichloro‐5‐pyrimidinecarboxaldehyde, 2, gave 2‐amino‐4‐chloro‐1,6‐dihydro‐6‐oxo‐5‐pyrimidinecarboxaldehyde, 5. The oxime of 2 rearranged to 2‐amino‐4‐chloro‐1,6‐dihydro‐6‐oxo‐5‐pyrimidinecarbonitrile, 8. Reaction of 8 with 4‐phenylbutylamine resulted in the displacement of the 4‐chloro atom to give compound 9. Hydrolysis of the cyano function of 9 gave amides 12, 13, and 14 depending on reaction conditions. A discussion of the 1H‐nmr spectrum of 2‐amino‐1,6‐dihydro‐6‐oxo‐4‐[(4‐phenylbutyl)amino]‐5‐ pyrimidinecarboxaldehyde, 6, is presented.
Synthesis and mass spectral fragmentation of 2‐methylthio‐7‐(p‐R‐phenyl)‐8‐phenoxy‐4,5‐benzo‐3‐aza‐2‐nonem. III
Authors: Cortés E. , Martínez R.
Published: March 2009

A series of new 2‐methylthio‐7‐(p‐R‐phenyl)‐8‐phenoxy‐4,5‐benzo‐3‐aza‐2‐nonem, IIIa, have been synthesized by regiospecific cycloaddition of phenoxyacetyl on to 2‐methylthio‐4‐(p‐R‐phenyl)‐3H‐1,5‐benzodiazepines IV. The structure was established by ir, 1H‐nmr and ms spectral data together with 13C‐nmr spectral data of desulfurization products, VIa. Likewise, a study has been made of the fragmentation upon electron impact of IIIa and IV. All the spectra analyzed contain molecular ions and the principal fragmentation routes takes place either from the molecular ion or from m/e (M+ — 134) ion. This ion is the base peak for all the compounds analyzed.
Synthesis of phenyl‐substituted 2H‐3,4‐dihydro‐3‐aminomethyl‐1,4‐benzoxazines. Intermediates for 1H‐2,3,3a,4‐tetrahydroimidazo[5,1‐c][1,4]benzoxazin‐1‐one derivatives. Part II
Authors: Banzatti Carlo , Heidempergher Franco , Melloni Piero
Published: March 2009

The synthesis of 2H‐3, 4‐dihydro‐3‐aminomethyl‐1, 4‐benzoxazines substituted by one phenyl group in the 2, 3 or α‐position is reported. The two diastereoisomers of the 2‐phenyl‐derivative were independently synthesized from ethyl trans‐3‐phenylglycidate by a stereospecific route. A previous attempt at the synthesis of these same compounds gave rise to an unexpected aliphatic‐aromatic ketone rearrangement.
Synthetic studies on potential metabolites of carcinogenic aza aromatic hydrocarbons. Part II. Non‐k‐region oxidised and reduced derivatives of 7‐methylbenz[c]acridine
Authors: Lap Bui Vinh , Boux L. J. , Cheung H. T. A. , Holder G. M.
Published: March 2009

Two phenolic derivatives of the weakly carcinogenic aza aromatic hydrocarbon 7‐methylbenz[c]acridine were prepared as reference compounds for studies of the mammalian metabolism of the carcinogen. Also, 1, 2, 3, 4‐ and 8, 9, 10, 11‐tetrahydro‐7‐methylbenz[c]acridine were made as intermediates for synthetic studies directed toward preparation of dihydrodiols of 7‐methylbenz[c]acridine.
Heterocycles from nitrile oxides. I. 5‐imino‐Δ2 ‐1,4,2‐oxathiazolines
Authors: Hussein Ahmed Q. , El‐Abadelah Mustafa M. , Sabri Wail S.
Published: March 2009

The reaction of some arylnitrile oxides with potassium thiocyanate in acetone at ambient temperature, has been investigated. Those having para‐ or meta‐halo (or nitro)substituents give 3‐aryl‐5‐imino‐Δ2‐1,4,2‐oxathiazolines as stable cycloadducts. ortho‐Substitutionn, on the other hand, led directly to the corresponding 5‐ (carbamido) imino analogues. The structures of these new heterocycles are supported by elemental analyses and spectral data.
The structure of sulfonium ylides stabilized by the malonylide moiety
Authors: Galloy J. , Watson W. H. , Craig D. , Guidry C. , Morgan Michael , Mckellar Robert , Ternay A. L. , Martin G.
Published: March 2009

The crystal structures of four thioxanthenium bis(carbomethoxy)methylides and methylides of di‐(p‐nitro‐phenyl)sulfonium and dimethylsulfonium have been determined. The carbanion moiety in all cases is planar and the pi‐system is rotated 90° with respect to the sulfur lone pair. All compounds exhibit a pseudo‐equatorial orientation of the carbanion system except for the 2,4‐dimethylthioxanthenium ylide. The compounds are described in terms of the geometries around the sulfur atom, the interplanar angles and sulfur‐oxygen and oxygen‐oxygen interactions. Surprisingly, the sulfur atom is not symmetrically placed with respect to the two phenyl rings in the thioxanthenium compounds. The sulfur is coplanar with one phenyl ring but is significantly out of the plane of the other. The 13C and 1H spectra of the ylides are discussed along with the temperature dependence which indicates restricted rotation about the +SC− bond in several cases. The factors contributing to the stability of the ylides are analyzed.
Synthesis of 1H,3H‐imidazo[1,5‐c]thiazole‐5,7‐[6H,7aH]‐dione and 7,8‐dihydro‐5‐H‐imidazo[1,5‐c][1,3]thiazine‐1,3‐[2H,8aH]‐dione and derivatives
Authors: Lalezari I. , Seifter S. , Thein A.
Published: March 2009

1H,3H‐Imidazo[1,5‐c]thiazole‐5,7‐[6H,7aH]‐dione and the corresponding 7‐thione derivatives as well as 7,8‐dihydro‐5H‐imidazo[1,5‐c][1,3]thiazine‐1,3‐[2H,8aH]‐dione and the corresponding 3‐thione derivatives were synthesized starting from L‐cysteine and DL‐homocysteine thiolactone, respectively. The second group of bicyclic compounds represents a new heterocyclic ring system. The structures of the compounds were confirmed by spectroscopic studies and elemental analyses.
Synthesis of 5H‐pyrazolo[5,1‐c][1,4]benzodiazepine
Authors: Cecchi Lucia , Filacchioni Guido
Published: March 2009

The reaction of 2‐nitrobenzyl bromide with dimethyl pyrazole‐3, 5‐dicarboxylate gave dimethyl 1‐(2‐nitrobenzyl)pyrazole‐3, 5‐dicarboxylate which through a few steps procedure afforded the key intermediate 5, 10‐dihydro‐11‐oxopyrazolo[5, 1‐c][l, 4]benzodiazepine. The latter was reduced and dehydrogenated to yield the new tricyclic system 5H‐pyrazolo[5, 1‐c][1, 4]benzodiazepine.
Nucleophilic substitution by 3‐amino‐1,2‐propanediol in nitropyrazines and nitroquinoxalines
Authors: Hartman George D. , Schwering John E.
Published: March 2009

Treatment of 2‐chloro‐3‐nitropyrazine and 2‐chloro‐5‐nitropyrazine with 3‐amino‐1, 2‐propanediol affords products derived from displacement of chloride, while similar reaction of methyl 3‐nitropyrazinoate and 2‐chloro‐3‐nitroquinoxaline gives clean nitro group replacement. Analogous reaction of methyl 6‐chloro‐3‐nitropyrazinoate affords a mixture containing products derived from competitive displacement of chloride and nitrite.
Reaction of 2‐acetamido‐3,7‐dihydropyrrolo[2,3‐d]pyrimidin‐4‐one with dimethylamine and formaldehyde. Formation of two isomeric mannich bases
Authors: Benghiat Eric , Crooks Peter A.
Published: March 2009

2‐Acetamido‐3, 7‐dihydropyrrolo[2, 3‐d)pyrimidin‐4‐one reacts with dimethylamine and formaldehyde in glacial acetic acid to afford the two isomeric Mannich products, 2‐acetamido‐3, 7‐dihydro‐5‐dimethylamino‐methylpyrrolo[2, 3‐d]pyrimidin‐4‐one, and 2‐acetamido‐3, 7‐dihydro‐6‐dimethylaminomethylpyrrolo[2, 3‐d]‐pyrimidin‐4‐one, in a ratio of 3:1, respectively.
Synthesis and characterization of 5H‐1,3‐dioxolo[4,5‐f]indoleethylamines
Authors: Grotjahn Douglas B.
Published: March 2009

Twelve new N, N‐dialkylated‐5, 6‐methylenedioxytryptamines and N‐cyclopropyl‐5, 6‐methylenedioxytrypt‐amine were prepared as hybrids of known psychoactive phenylethylamines and tryptamines. Novel, more convenient syntheses of N‐methyl‐ and N‐benzylcyclopropylamine are described.
Synthesis of some substituted pyrido[1,2‐a]pyrimidin‐4‐ones and 1,8‐naphthyridines
Authors: Ferrarini Pier Luigi , Mori Claudio , Livi Oreste , Biagi Giuliana , Marini Anna Maria
Published: March 2009

The substituted 4H‐pyrido[1, 2‐a]pyrimidin‐4‐ones (I) were obtained by the condensation of substituted 2‐aminopyridines with δ‐ketocarboxylic esters in PPA. Some of the derivatives I were transformed into the corresponding 1, 8‐naphthyridines II and III.
Synthesis of 6‐methoxy‐2,2‐dimethyl‐2H‐1‐benzothiopyran and 6,7‐dimethoxy‐2,2‐dimethyl‐2H‐1‐benzothiopyran, sulfur analogues of precocene I and precocene II
Authors: Camps F. , Colomina O. , Coll J. , Messeguer A.
Published: March 2009

Preparation of title compounds 5, sulfur analogues of the natural insect antijuvenile hormones precocene I and II, is described. The synthetic pathway involves conversion of the appropriate thiophenol 2 into the corresponding thiochroman‐4‐one 4 followed by reduction and dehydration. The 13C nmr data for all the above products are also reported.
Chiral 1,4‐benzodiazepines. XII. Conformation in a solution of 7‐chloro‐5‐phenyl‐3(S)methyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepine
Authors: Decorte E. , Toso R. , Fajdiga T. , Comisso G. , Moimas F. , Sega A. , Sunjić V. , Lisini A.
Published: March 2009

Deuterium labeled congeners of 7‐chloro‐5‐phenyl‐3(S)‐methyl‐1,3‐dihydro‐2H‐1,4‐benzodiazepine (8), i.e., compounds 9 and 16‐18 were prepared and their lis‐nmr spectra run. For computational studies compounds 9 and 16 were chosen. The results of lis measurements revealed that 16 is present in more than 97% in the boat‐like conformation I (Scheme 3).
Novel synthesis of 5,11‐dihydro‐6H‐pyrido[2,3‐b]‐[1,4]benzodiazepin‐6‐ones and related studies
Authors: Oklobdžija M. , Comisso G. , Decorte E. , Fajdiga T. , Gratton G. , Moimas F. , Toso R. , Šunjić V.
Published: March 2009

5,11‐Dihydro‐6H‐pyrido[2,3‐6][1,4]benzodiazepin‐6‐one (1), a basic intermediate in the preparation of 11‐α‐aminoacetyl derivatives with important biological activities, has been obtained by a three‐step synthesis starting from easily available isatoic anhydride and anhydro ornithine. Some model cyclisation reactions leading to 5‐member ring derivatives 10 and 12 instead of 7‐member ring analogues of 1, are reported. Easy transformations of the tetrahydro congener of 1, i.e., compound 4 into 19, which actually represents a tetrahedral intermediate in the transformation of 5 into 4, is noticed. Further rearrangement of 19 into spiro compound 20, and return of the latter into 5 is described.
Attempts at new synthesis of 5,11 ‐Dihydro‐6H‐pyrido[2,3‐b][1,4]benzodiazepin‐6‐one
Authors: Oklobdžija M. , Comisso G. , Decorte E. , Kovač T. , Angeli C. , Moimas F. , Zanon P. , Zonno F. , Toso R. , Šunjić V.
Published: March 2009

Attempting some new approaches to 5,11‐dihyro‐6H‐pyrido[2,3‐b][1,4]benzodiazepin‐6‐one (6), compounds 8, 10 and 11 were prepared. Ring enlargement of 4 into 6 failed, as well as condensation of 10 and 11 into ID, which is the potential precursor of pirenzepin (11‐[2′‐(4″‐methylpiperazin‐1″‐yl)]acetyl derivative of 6) via an envisaged intramolecular Diels‐Alder reaction. Model compounds 5 and 13 were prepared and their behaviour in analogous reactions explained the failures of the intended transformations of 4, as well as of condensation of 10 and 11.
Friedländer condensation of 1H‐pyrazolin‐5‐ones with O‐aminobenzaldehydes. Synthesis of 1H‐pyrazolo[3,4‐B]quinolines
Authors: Tomasik Danuta , Tomasik Piotr , Abramovitch Rudolph A.
Published: March 2009

All the possible 1‐ and 3‐monomethyl, monophenyl, dimethyl, diphenyl, and methylphenyl‐1H‐pyrazolin‐5‐ones have been condensed with o‐aminobenzaldehyde. In some cases (but not all) 1‐H‐pyrazolo[3,4‐b]quinolines (10) are formed together with a variety of other products. The balance between formation of hydrazone 11 and the ring‐closed 10 is discussed, as is the formation of other products obtained in these condensations.
Imino‐Bridged heterocycles. V . Synthesis of 6,11‐dimethyl‐1 1H‐benzo[5,6]cyclohepta[1,2‐c]pyridin‐6,11‐imine by a regiospecific amide to olefin cyclization
Authors: Brenner Daniel G. , Halczenko Wasyl , Shepard Kenneth L.
Published: March 2009

Attempted utilization of sulfenimines 6a,b to prepare tertiary carbinamines as intermediates to the desired 6,11‐dimethyl‐11H‐benzo[5,6]cyclohepta[1,2‐c]pyridin‐6,11‐imine system (10) instead gave products resulting from nitrogen‐sulfur bond cleavage. The preparation and use of the corresponding sulfonimine 8, however, led to 10 through a regiospecific base‐catalyzed reaction.
Synthesis of heterocyclic compounds from o‐aminobenzenethiol and ammonium thiocarbamate
Authors: D'Amico John J. , Fuhrhop Ralph W. , Bollinger Frederic G. , Dahl William E.
Published: March 2009

The reaction of o‐aminobenzenethiol with carbonyl sulfide in the presence of triethylamine afforded an alternate route for the synthesis of 2‐benzothiazolinone (1) in 97–98% yield. The reaction of ammonium thiocarbamate (2) with 2‐chlorocyclohexanone furnished the novel 4,5,6,7‐tetrahydro‐2‐benzothiazolinone (3). 3‐Ethoxy‐2H‐1,4‐benzothiazin‐2‐one (7) was prepared by the reaction of o‐aminobenzenethiol with diethyl oxalate. Possible pathways and supporting nmr, ir and mass spectra are discussed.
Synthesis of 4‐hydrazino‐5H‐pyrimido[5,4‐b]indole and related compounds
Authors: Monge A. , Palop J. A. , Goñi T. , Martinez‐Crespo F. , Recalde I. , Fernandez‐Alvarez E.
Published: March 2009

This paper describes the synthesis of two 4‐amino‐5H‐pyrimido[5,4‐b]indoles 5, 4‐hydrazino‐5H‐pyrimido[5,4‐b]indole 6, two 1,2,4‐triazolo[4,3‐c]pyrimido[5,4‐b]indoles 8, and tetrazolo[4,5‐c]pyrimido[5,4‐b]indole 10. Starting with ethyl 3‐aminoindole‐2‐carboxylate 1, 5H‐pyrimido[5,4‐b]indol‐4‐one 2 was obtained (80%) by condensing with formamide. Reactions of 2 with phosphorus oxychloride and phosphorus pentasulfide gave respectively, 4‐chloro‐5H‐pyrimido[5,4‐b]indole 3 (70%) and 5H‐pyrimido[5,4‐b]indole‐4‐thione 4 (80%). Compound 3 reacted with amines (morpholine, piperidine) to give the respective 4‐amino‐5H‐pyrimido[5,4‐b]‐indoles 5, and compound 4 reacted with hydrazine to give 4‐hydrazino‐5H‐pyrimido[5,4‐b]indole 6 (80%). Two hydrazones of 6 (benzylidene, isopropylidene) 7 were also prepared (90%). Compound 6 reacted with formic and acetic acids to give (65–75%) the respective 1,2,4‐triazolo[4,3‐c]pyrimido[5,4‐b]indoles 8 and with nitrous acid to give tetrazolo[4,5‐c]pyrimido[5,4‐b]indole 9 (85%). All the new compounds 2 to 9 were characterized by elemental analysis and spectral data (ir, nmr).
Zur protonenkatalysierten elektrophilen substitution von 2,3‐dimethylindol mit arylaldehyden: C6‐regioselektivität am indol‐gerüst
Authors: Schiffl E. , Pindur U.
Published: March 2009

The proton catalyzed reaction of 2,3‐dimethylindole (1) with several arylaldehydes 2 yields the 6,6′bisindolylarylmethanes 5 regioselectively. No mechanistic information about the predominant attack of the aldehydes on the indole nucleus is obtained, because the reaction proceeds too fast to control. The electron‐rich aldehydes, 2,4,6‐trimethoxybenzaldehyde and indole‐3‐carbaldehyde, yield exclusively the 6,6′,6″‐trisin‐dolylmethane 9. The constitutions of all isolated methanes were elucidated by 400 MHz 1H‐nmr spectroscopy.
Optically active synthons containing tetra‐ and dihydropyrimidine rings
Authors: Weis Alexander L. , Frolow Felix , Vishkautsan Rosita
Published: March 2009

Optically active condensed derivatives of hydroxytetrahydropyrimidines and dihydropyrimidines were prepared by condensation of (+)pulegone with amidines and guanidine. The structure, the possible mechanism of formation of these compounds, and the existence of amidinic tautomerism are discussed on the basis of the measured spectral data and x‐ray diffraction analysis.
Synthèse d'hétérocycles polycondensés à partir de benzopyranno‐1 as‐triazinones
Authors: Vinot Nicole , Maitte Pierre
Published: March 2009

Par des réactions de substitution sur le carbonyle des benzopyranno‐1 as‐triazinones 1 et 2 il est facile de préparer les chloro, hydrazino et aminobenzopyranno‐1 as‐triazines. Ces composés, par condensation avec les acides ou les cétones α‐bromées, ont permis la synthèse de triazolo et imidazolobenzopyranno‐1 as‐triazines 9, 10, 17, 18. Enfin la réaction classique du nitrite de sodium sur les hydrazinotriazines donne les tétrazolotriazines 13, 14.
Mass spectral fragmentation patterns of heterocycles. IX . Investigation of fundamental processes in 5H‐dibenz[b,f]azepines and dihydro‐5H‐dibenz[b,f]azepines
Authors: Al‐Showaier Ibrahim , Hallberg Anders , Schram Karl H. , Martin Arnold R.
Published: March 2009

Electron impact induced fragmentation patterns of 5H‐dibenz[b,f]azepine (1a), 10,11‐dihydro‐5H‐dibenz‐[b,f]azepine (2a) and some 5‐substituted derivatives were investigated using metastable ion studies, exact mass measurements and deuterated analogues. Studies employing 4,6‐dideuterio derivatives indicate that the formations of ions of m/e 191, 180, 167, 166 and 152 are associated with a variety of skeletal reorganization processes accompanied by hydrogen (or deuterium) transfers involving peri (4‐ or 6‐) hydrogen (or deuterium) atoms. The methyl radical expelled in the formation of the M‐15 ion in the spectrum of 2a is derived from the benzylic carbon(s). A similar process is, in part, responsible for the expulsion of a methyl radical from the molecular ion of 5‐methyl‐10,1 1‐dihydro‐5H‐dibenz[b,f]azepine (2c) based on the fragmentation of the trideuteriomethyl derivative (2d). Side chain α‐cleavage processes dominate the spectra of (5H‐dibenz[b,f]azepine‐5‐yl)acetaldehyde diethylacetal and its 10,11‐dihydro analogue. Hydrogen atom transfer processes involving benzylic hydrogen atoms occur in the fragmentation of the 10,11‐dihydro‐5H‐dibenz[b,f]azepines 2a, 2c and 2e.
Syntheses and reactions of some 1‐substituted‐7‐alkyl‐2‐thioxopurines: X‐Ray structure of 6‐methylamino‐7‐nonyl‐2‐thioxopurine
Authors: Grözinger Karl G. , Onan Kay D.
Published: March 2009

Several 1‐substituted‐7‐alkyl‐2‐thioxopurines 8,9,10 were synthesized by the reaction of isothiocyanates with 1‐alkyl‐4‐amino‐5‐cyanoimidazoles 3. Treatment of 3 with methyl isothiocyanate gave the Dimroth rearranged product 6‐methylamino‐7‐alkyl‐2‐thioxopurines 11. The structure of 11 was unambiguously defined by X‐ray crystallography.
Antibakterielle wirkstoffe. IX . Die aminomethinylierung im system des 3‐methyi‐1‐(4‐nitrophenyl)‐2‐pyrazolin‐5‐ons
Authors: Kreutzberger Alfred , Kolter Karl
Published: March 2009

Die mit Hilfe von s‐Triazin (1) durchgeführte Aminomethinylierung von 3‐Methyl‐1‐(4‐nitrophenyl)‐2‐pyrazolin‐5‐on (2) führt zu dem Aminomethinylierungsprodukt 4 und dem C‐Rubazonsäuretypus 5. In den zur Untermauerung der erhaltenen Strukturen aufgenommenen Massenspektren treten als charakteristische Fragmente von 4 das Pyrazolo[4,3‐d]isoxazolyliumion 6 (m/e 245), p‐Benzochinonmonoiminylkation (m/e 106) und Mthylenaminophenylkation (m/e 104) auf.
Interaction of 2,4,6‐heptanetrione with 1,5‐diamino‐3‐azapentane and similar polyamines. The crystal and molecular structure of a new heterocyclic compound
Authors: Fregona D. , Sitran S. , Vigato P. A. , Casellato U. , Graziani R.
Published: March 2009

The pathway of the reaction between 2,4,6‐heptanetrione and 1,5‐diamine‐3‐aza‐pentane was studied and some products identified by ir, uv, mass spectra and x‐ray diffractometry. This reaction is not a simple condensation with the formation of a Schiff base but a more complicated process. The structure of the final compound was determined by x‐ray crystallography and refined to R = 0.047. Crystals are triclinic, space group Pl, with a = 11.795(5), b = 9.779(5), c = 7.801(5) Å, α = 101.74(3), β = 90.93(3), γ = 110.65(3), Dx = 1.27 g. cm−3 for Z = 2. The structure is essentially formed by three heterorings two of which have a common edge. Only the 4‐pyridone ring is planar.

As expected 1,5‐diamino‐3‐thiapentane reacts with the same triketone, in 1:1 or 1:2 molar ratios, to give the acyclic or macrocyclic Schiff bases.
Synthesis of the angular furanoxanthone, deoxydehydropsorospermin methyl ether (5,10‐dimethoxy‐2‐isopropenyl‐6H‐furo[2,3‐c]xanthen‐6‐one)
Authors: Scannell Ralph T. , Stevenson Robert
Published: March 2009

The angular isopropenylfuranoxanthone heterocyclic system, on which the anti‐leukemic natural product psorospermin is based, is synthesized by the reaction of cuprous isopropenylacetylide with 4‐bromo‐1,5‐dimethoxy‐3‐hydroxyxanthone.
Selenium heterocycles. XXXVII . Synthesis of 4‐(thiazol‐4‐yl)‐1,2,3‐selenadiazoles and 4‐(selenazol‐4‐yl)‐1,2,3‐selenadiazoles
Authors: Shafiee A. , Anaraki M. , Bazzaz A.
Published: March 2009

Starting from readily available 2‐substituted‐4‐formylthiazoles and selenazoles, a series of 4‐(2‐aryl‐4‐selenazolyl)‐1,2,3‐selenadiazoles I and 4‐(2‐substituted‐4‐thiazolyl)‐1,2,3‐selenadiazoles II were prepared. Pyrolysis of compound II afforded (2‐substituted‐4‐thiazolyl) acetylenes VII. Addition of potassium hydroxide pellets to an alcoholic solution of II gave 2‐substituted‐1,4‐diselenafulvenes VIII. Decomposition of compound II with base followed by the addition of carbon disulfide gave 5‐substituted 2‐thioxo‐1,3‐thiaselenoles XI.
Reactions of sulfur monochloride with some aromatic aldehyde semicarbazones and thiosemicarbazones: New syntheses of substituted 2,4‐dihydro‐1,2,4‐triazol‐3‐ones, 2,4‐dihydro‐1,2,4‐triazole‐3‐thiones and 2‐amino‐1,3,4‐oxadiazoles
Authors: Milcent René , Nguyen Thu‐Huong
Published: March 2009

Treatment of various substituted semicarbazones of aromatic aldehydes with sulfur monochloride yields the corresponding substituted 2,4‐dihydro‐1,2,4‐triazol‐3‐ones. With thiosemicarbazones, the products are derivatives either of the 2‐amino‐1,3,4 thiadiazole or of the 2,4‐dihydro‐1,2,4‐triazole‐3‐thione depending on the experimental conditions.
Azolopyrimidines and pyrimidoquinazolines from 4‐chloropyrimidines
Authors: El‐Reedy A. M. , Ayyad A. O. , Ali A. S.
Published: March 2009

5‐Cyano‐3,4‐dihydro‐6‐phenyl‐2‐substitutedpyrimidin‐4‐ones 1a‐c reacted with phosphorus oxychloride to give the corresponding 4‐chloropyrimidine derivatives IIa‐c. Compounds IIa‐c reacted with aniline and hydrazine to yield the 4‐anilino, IIIa,e, and 4‐hydrazino, IIIb‐d derivatives. The 4‐hydrazino analogues IIIb,c could be converted into the triazolo[4,3‐c] and tetrazolo[4,5‐c]pyrimidines IV and V by the action of carbon disulphide and nitrous acid, respectively. The reaction of IIb,c with phenylhydrazine afforded directly the 5‐amino‐4,6‐diphenyl‐6H‐2‐substitutedpyrazolo[3,4‐d]pyrimidines VIa,b. The 4‐chloro derivative IIa reacted with antrhanilic acid to form the 5‐cyano‐2,4‐diphenyl‐6‐(o‐carboxyphenylamino)pyrimidine VIII, which could be cyclised into the 4‐cyano‐1,3‐diphenyl‐10H‐pyrimido[6,1‐b]quinazolin‐10‐one IX by heating with acetic anhydride.