bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, Spectroscopic Investigation and Biological Activity of Metal(ll) Complexes with N2O4 Ligands
Authors: El-Tabl Abdou Saad , Plass Winfried , Buchholz Axel , Shakdofa Mohamad M.E.
Published: December 2009

A new series of Mn(II), Ni(II), Co(II) and Cu(ll) complexes derived from diacetylmonoxime and 2-, 4- and 6-aminobenzoic acids have been prepared and characterised by elemental and thermal analyses (DTA, DTG and TG) as well as 1H and 13C NMR, IR, UV-Vis., Mass and ESR spectra, magnetic susceptibility and conductance measurements. The IR spectral data show that the ligands behave as mono- or di-basic, bis-, tri-, or tetradentate-chelates towards the metal ion. The stability of the complexes is achieved via intra- and inter-molecular hydrogen bonding of the OH-group with the oximato-oxygen atom or oxygen atom of a carboxylic group, giving polymeric networks in the solid state. Molar conductances in DMF solution indicate that the complexes are non-electrolytes. The ESR spectra of solid complexes [Co (HL1)21.2H2O (4), [Mn(HL1)2].H2O (5), [Mn(HL2)2(H2O)2].H2O (10), [Cu2(HL3)2(OAc)2(H2O)4] (12) and [(Mn)3 (L3)2(OAc)2(H2O)6].4H2O (15) at room temperature and 77 K, are isotropic, however, the copper(ll) complexes [Cu(HL1)(OAc)(H2O)2}2] (2) and [Cu(HL2)2(H2O)2].H2O (7) are non-axial and axial (dx2-y2) respectively with covalent bond character. The metal complexes exhibit greater inhibitory effects than tetracycline (bacteria) and amphotricen (fungi).
Synthesis, Reactions and Antimicrobial Activity of Thieno[2,3-c]pyridazine Derivatives
Authors: Mariah Fatma El
Published: December 2009

The reaction of N1-(un)substituted 4-aminosulfonamide with 6-chloropyridothienopyridazine (5) and 8-chloro-pyrimidothienopyridazine (14) gave 6-substituted aminopyridothienopyridazine (9) and 8-substituted amino-pyrimidothienopyridazine (16) respectively. All of the derivatives have been characterised by analytical and spectroscopic studies and also tested for their in vitro antibacterial and antifungal activity against a variety of microorganisms.
Synthesis of furan annulated heterocycles via a one-pot three-component reaction
Authors: Mosslemin Mohammad Hossein , Anary-Abbasinejad Mohammad , Nia Abbas Fazli , Bakhtiari Samaneh , Anaraki-Ardakani Hossein
Published: December 2009

Three-component reaction between 4-hydroxycoumarin, or 5,5-dimethyl-1,3-cyclohexandione, arylglyoxals, and alkyl isocyanides in acetonitrile afforded furocoumarin or benzofuran derivatives in high yields.
Synthesis and antibacterial activity of novel quinoxalinone derivatives
Authors: Shaaban Mohamed A. , Khalil Omneya M. , Ahmed Khaled R. , Lamie Phoebe F.
Published: December 2009

The reaction of 3-hydrazinocarbonylmethylquinoxalin-2(1H)-one with phthalic anhydride, certain aromatic aldehydes, isocyanates and phenyl isothiocyanate furnished corresponding imide, Schiff's, semi- and thiosemicabazide derivatives. Treatment of 3-[2-(phenylcarbamoyl)hydrazinocarbonylmethyl]quinoxalin-2(1H)-one with chloroacetic acid, sulfuric acid and sodium hydroxide yielded cyclised derivatives. Moreover, 3-[2-bromobenzylidenehydrazinocarbonyl-methyl]quinoxalin-2(1H)-one was cyclised to oxadiazolinyl derivative using acetic anhydride. Furthermore, 3-[5-sulfanylidene-4,5-dihydro-1,3,4-oxadiazol-2-yl)methyl]quinoxalin-2(1H)-one was employed as a precursor in the synthesis of some novel 2(1H)-quinoxalinones. Some of the newly prepared compounds were evaluated for in vitro antibacterial activity using ofloxacin as the reference standard.
Ytterbium triflate catalysed Friedel–Crafts reaction using carboxylic acids as acylating reagents under solvent-free conditions
Authors: Jin Can , Li Jie , Su Weike
Published: December 2009

The Friedel–Crafts acylation of 1-naphthol and phenol derivatives with carboxylic acids were investigated by using a catalytic amount of metal-triflate, in particular Yb(OTf)3, under solvent-free conditions. Both aliphatic and aromatic carboxylic acids reacted easily to afford the corresponding hydroxyaryl ketones.
Synthesis of polyfunctional substituted pyrazoles
Authors: El-Shehry Mohamed F. , El-Telbani Emad M. , Swellem H. Randa
Published: December 2009

Synthesis of pyrazoles incorporating substituted derivatives of 2, 4-dichloroacetic acid residues is described. Reactions with different reagents afford fused and polyfunctional substituted pyrazoles.
Synthesis of bipyrazole and 1,3,4-thiadiazole derivatives
Authors: Dawood Kamal M. , Ragab Eman A. , Farag Ahmad M.
Published: December 2009

New hydrazonoyl bromides reacted with several C-nucleophiles to give the corresponding bipyrazoles. Treatment of 3-cyanoacetylpyrazole derivatives with phenyl isothiocyanate in potassium hydroxide followed by hydrazonoyl bromides gave the corresponding pyrazolyl-1,3,4-thiadiazoles.
Annelation of Baylis–Hillman Derivatives: Synthesis of Highly Functionalised Tetrahydronaphthalenes
Authors: J'mour Asma , Rezgui Farhat
Published: December 2009

PTSA-promoted Robinson annelation of α-(3-oxobutyl)cyclohex-2-en-1-one derivatives in refluxing toluene, affords efficiently in a one pot process a variety of hydroxytetrahydronaphthyl carbonyl compounds in good yields. Further highly regioselective electrophilic bromination of these intermediates gave the corresponding bromide derivatives in 92–97% yield.
A convenient synthesis of novel symmetrical bis-Schiff bases of 2, 2'-thio-bis[4-methyl(2-aminophenoxy)phenyl ether] in solution and under solvent-free conditions
Authors: Shockravi Abbas , Sadeghpour Mahdieh , Olyaei Abolfazl
Published: December 2009

A convenient and straightforward procedure for the synthesis of novel symmetrical bis-Schiff bases has been achieved through the condensation of the symmetrical primary bis-amine 2,2'-thio-bis[4-methyl(2-aminophenoxy) phenyl ether] with a series of aryl aldehydes in organic solvents at room temperature and in solvent-free media, in moderate to high yields.
NMR Study of the Naphtho-1,3-dithioles Formed from Carbamodithioates and 2,3-dichloro-1,4-naphthoquinone
Authors: Aly Ashraf A. , Brown Alan B. , El-Shaieb Kamal M. , Hassan Alaa A. , Bedair Tarek M. I.
Published: December 2009

Reaction of triethylammonium 1,2-ethanediylbis(carbamodithioate) with 2,3-dichloro-1,4-naphthoquinone in DMF furnished N,N'-ethylenebis(2-iminonaphtho[2,3- d][1,3]dithiole-4,9-dione) in 94% yield. Triethylammonium N-arylcarbamodithioates reacted with 2,3-dichloro-1,4-naphthoquinone to give 2-( N-arylimino)naphtho[2,3- d][1,3] dithiole-4,9-diones in good yields. NMR spectroscopic data of the products are discussed.
1β-hydroxylfriedelin, a new natural pentacylic triterpene from the sclerotia of Polyporus umbellatus
Authors: Zhao Yingyong , Yang Libin , Wang Minchang , Wang Lili , Cheng Xian-long , Zhang Yongmin , Lin Rui-chao , Sun Wen-ji
Published: December 2009

A new pentacylic triterpene, 1β-hydroxylfriedelin, has been isolated from the sclerotia of Polyporus umbellatus (Pers.) Fries (Polyporaceae) together with 18 known compounds (2–19). The structures of these compounds were elucidated on the basis of spectral data.
Scandium triflate-catalysed synthesis of N-substituted pyrroles from amine and 2,5-dimethoxytetrahydrofuran
Authors: Zuo Bing , Chen Jiuxi , Liu Miaochang , Ding Jinchang , Wu Huayue , Su Weike
Published: December 2009

The Clauson–Kass pyrrole synthesis catalysed by scandium triflate afforded N-substituted 2- and 3-unsubstituted pyrroles with yields ranged from good to excellent. Aromatic amines, heteroaomatic amines, 4-methylbenzenesulfonamide and 2-chlorobenzamide are good substrates in this transformation.
Antimicrobial activity of novel fused nitrogen, sulfur and phosphorus containing-heterocycles and relevant phosphonates with difurylpyridazine species
Authors: Abdou Wafaa M. , Shaddy Abeer A. , Sediek Ashraf A.
Published: December 2009

Treatment of 5,6-di(2-furyl)-3-thioxo-2,3-dihydropyridazine-4-carbonitrile with phosphonate carboanions stabilised with electron withdrawing group (CO2R, CN, SR’) led, under microwave irradiation and the effect of basic catalysis, to excellent yields of a variety of condensed sulfur, nitrogen and phosphorus-containing heterocycles as major products, along with fused thieno- and thiazole ring systems bearing a phosphonate moiety. On the other hand, fused thiazaphosphinine oxide and thiopyranone phosphonate were obtained in equal yields from the reaction of 5,6-di(2-furyl)-3-thioxo-2,3-dihydropyridazine-4-carbonitrile with diethyl vinylphosphonate. Screening results of antimicrobial potency for the products were discussed in terms of structure-activity relationships (SAR), and an attempt was made to define the structural features for lead compounds.
Iodine-promoted cleavage of the C-17-dihydroxyacetone side chain of corticosteroids in aqueous ammonia water
Authors: Sun Liang , Geng Xin , Liu Lanhai , Jiang Chenggang , Wang Cunde
Published: December 2009

A convenient approach to 17-ketosteroids by the iodine-promoted cleavage of the C-17-dihydroxy acetone side chain of corticosteroids is described. Treatment of steroids containing the C-17-dihydroxyacetone side chain with iodine and an excess of aqueous ammonia in acetonitrile at 50°C, affords high yields of the corresponding 17-ketosteroids.
Crystal structures of two N-phenylated tricyclic benzothiazines with antimalarial activity
Authors: Barazarte Arthur , Gamboa Neira , Rodrigues Juan , Atencio Reinaldo , González Teresa , Charris Jaime
Published: December 2009

The crystal structures of two N-phenylated tricyclic benzothiazines were determined 3-amino-7-chloro-9-phenyl-1,9H-pyrazolo-[4,3-b]benzothiazine 4,4-dioxide, C15H11ClN4O2S crystallises in P21/c with a = 11.436 (4)Å, b = 10.894 (3)Å, c = 11.858 (4)Å, β = 95.297 (9)°, V = 1471.0 (8) Å3 and Z = 4, while 2,4-diamino-8-chloro-10H-phenylpyrimido-[5,4-b]benzothiazine 5,5-dioxide, C16H12ClN5O2S crystallises in P21/c with a = 7.496 (2)Å, b = 17.7 28 (4)Å, c = 11.889 (2)Å, (3 = 91.524 (5)°, V = 1579.4 (5)Å3 and Z = 4. Both molecules are essentially planar, including the exocyclic groups. These compounds were promising as inhibitors of hemoglobin hydrolysis, however, their effect as inhibitors of β-hematin formation was marginal. The most active compound to emerge from the in vitro and in vivo murine studies was the pyrimidobezothaizine, suggesting an antimalarial activity via inhibition of haemoglobin hydrolysis, but it was not as efficient as chloroquine.
Synthesis, structure, properties and a theoretical study of [ZnCl2(4,4'-bipy)]n
Authors: Xie Yiming , Wu Jihuai
Published: December 2009

The compound [ZnCl2(4,4'-bipy)] n, has been synthesised via hydrothermal reaction and structurally characterised. It crystallises in the space group Cc of the monoclinic system: a = 15.883(5), b = 25.656(5), c = 14.642(6) Å, β = 110.321(4)°, V = 5595(3) Å3, C10H8Cl2N2Zn, M r= 292.45 g mol−1, D c= 1.736 g cm−3, S = 1.003, μ(Mo Kα) = 2.636 mm−1, F(000) = 2920, R = 0.0471 and wR = 0.0946. The complex has a one-dimensional zigzag chain-like structure. Photoluminescent investigation reveals that it displays a strong emission in the purple region and molecular orbital (MO) calculation indicates that the emission originates from the ligand-to-ligand charge-transfer (LLCT) transition.
A facile synthesis of flavones catalysed by gallium(III) triflate
Authors: Jin Can , He Fei , Wu Huayue , Chen Jiuxi , Su Weike
Published: December 2009

Ga(OTf)3 was explored as a novel catalyst for the cyclisation of 1-(2-hydroxyphenyl)-3-aryl-1,3-propanediones in nitromethane to flavones with excellent yields.
Interaction of adenosine, guanosine and inosine with ruthenium hydride complexes
Authors: Ghose Ranjana
Published: December 2009

Complexes of adenosine, guanosine and inosine with some ruthenium hydride complexes have been prepared and studied by UV, visible, IR, 1H NMR and 13C NMR spectroscopies. The ligands have been found to coordinate through their exocyclic groups and the N(7) atom to the RuHCl(PPh3)3 unit and through only exocyclic groups to the RuHCl(CO)(PPh3)3 unit.
PPh3-catalysed One-Pot Three-Component Syntheses of α-aminophosphonates under Solvent-Free Conditions
Authors: Tian You-Ping , Xu Feng , Wang Yi , Wang Jian-Jun , Li Hui-Li
Published: December 2009

A simple and efficient preparation of α-aminophosphonates under relatively mild conditions by the one-pot reaction of aldehydes with amines and dialkyl phosphites using catalytic amounts of triphenylphosphine is described.
Selenium-containing heterocycles: Part 2. Reactions of 3-amino-4,6-dimethyl-selenolo[2,3-b]pyridine-2-carbonitrile and related fused tetracyclic systems
Authors: Abdel-Hafez Shams H. , Ahmed Ragaa A. , Abdel-Azim Mohamed A. , Hassan Khairy M.
Published: December 2009

A novel series of pyrido[3’,2’:4,5]selenolo[3,2- d]pyrimidine, 7,9-dimethylpyrido [3’,2’:4,5]selenolo[3,2- d]pyrimidine-2,4-( 1H,3H)-dithione, 7,9-dimethylpyrido[3’,2’:4,5]selenolo[2,3- e]tetrazolo[1,5- c]pyrimidine-6( 5H)-thione, 9,11-dimethyl-pyrido[3’,2’:4,5]selenolo[2,3- e][1,2,4]triazolo[1,5- c]pyrimidine, 7,9-dimethylpyrido[3’,2’:4,5]selenolo[2,3- e]imidazo[1,2- c] pyrimidine and 10,12-dimethylpyrido[3″,2″:4’,5']selenolo[3’,2’:4,5]pyrimido[1,6- a]pyrimidine derivatives were prepared from 3-amino-4,6-dimethylselenolo[2,3- b]pyridine-2-carbonitrile.
Synthesis of Stilbenes Promoted by the Mixture of Zinc and Iron Powder
Authors: Zhang Zhiying , Xie Yuanyuan , Yu Xiaochun
Published: December 2009

Stilbenes have been synthesised by a one-pot reaction of aldehydes with benzyl bromide. The reaction was promoted by both triphenylphosphine and the mixture of zinc and iron together in sealed tube. The yields ranged from moderate to excellent.
Synthesis of New Bipyridine-Containing Polystyrene Derived from 1,10-phenanthroline
Authors: Cang Hui , Wang Siqing , Yang Wenzhong , Wang Jintang
Published: December 2009

This report describes the synthesis of two new bipyridine-containing polystyrene compounds from 1,10-phenanthroline by four steps.
Synthesis of 1,2,4-triazoles, imidazoles, pyrimidines, quinazolines, 1,3,5-triazines, and 1,3-thiazines from 3-oxo-5,6-diphenyl-2,3-dihydro-pyridazine-4-carbonyl isothiocyanate
Authors: Hemdan Magdy M. , Elshahawi Manal M.
Published: December 2009

3-Oxo-5,6-diphenyl-2,3-dihydropyridazine-4-carbonyl isothiocyanate (1) was reacted with hydrazine hydrate, or phenyl hydrazine, to give 1,2,4-triazole derivatives in a one pot-reaction. However, reaction of 1 with benzoyl hydrazine afforded thiourea derivative that was cyclised to a differently substituted 1,2,4-triazole. Ethyl glycinate reacted with isothiocyanate 1 to give an adduct that was cyclised to imidazolidine derivative. Reaction of 1 with o-aminophenol, o-phenylenediamine or o-aminothiophenol afforded benzoxazole, benzimidazole or benzothiazole derivatives respectively. Reaction of 1 with thioglycolic acid gave 1,3-thiazine derivative, however, when 1 was treated with anthranilic acid a thiourea derivative was obtained which cyclised to a quinazoline derivative. Reaction of 1 with 2-cyanoacetamide or guanidine HCl yielded pyrimidine or triazine derivatives respectively. The structures of all compounds were confirmed by their micro analytical and spectral data.
Synthesis and Characterisation of D–π–D Type Schiff Base Ligands Derived from Fluorene and 1,10-phenanthroline and its Complexes with Ruthenium(II)
Authors: Elmali Fikriye Tuncel , Erden İrahim , Demirhan Nebahat , Avciata Ulvi
Published: December 2009

A fluorene derivative, 9 H-fluoren-9-one(diphenylmethylene)hydrazone has been synthesised from the reaction of 4,5-diazafluoren-9-one with benzophenone hydrazone and a 1,10-phenanthroline derivative, N-[(1E,2E)-3-phenylprop-2-en-1-ylidene]-1,10-phenanthrolin-5-amine has been synthesised from the reaction of 5-amino-1,10-phenanthroline with cinnamaldehyde. Ru(II) complexes of these ligands have been prepared and characterised.
One-Pot Synthesis of thiocarbamidoalkyl naphthols
Authors: Zhang Zhong-Ping , Wen Jian-Ming , Li Jing-Hua , Hu Wei-Xiao
Published: December 2009

An efficient, inexpensive and mild method for the synthesis of β-thiocarbamidoalkyl-β-naphthols, catalysed by p-toluenesulfonic acid at room temperature is reported. A set of thiocarbamidoalkyl naphthols have been synthesised in high yields from aromatic aldehydes, β-naphthol and N-phenylthiourea or thiourea. The procedure involves a short reaction time and a simple experimental procedure.
A New Flavonol Glycoside from Tridax Procumbens Linn
Authors: Yuan Ke , Xu Runsheng , Chen Cungui
Published: December 2009

A new flavonol glycoside which has been isolated from the Tridax procumbens Linn. The present work deals with the isolation and identification of flavonol glycoside, characterised as 8,3′-dihydroxy-3,7,4′-trimethoxy-6-0-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside flavonol. Its structure elucidated using spectral data.
A Novel ent-kaurane Diterpenoid from Pteris Semipinnata
Authors: Zhan Zha-Jun , Zhang Fu-Yu , Li Cheng-Ping , Shan Wei-Guang
Published: December 2009

The chemical investigation of the aerial parts of Pteris semipinnata furnished a novel ent-kaurane diterpenoid, and three known sesquiterpenoids with a 1-indanone skeleton, namely (2 R)-pterosin B, (2 S, 3 S)-pterosin C and norpterosin C. The structure of 7β-hydroxy-11β, 16β-epoxy- ent-kauran-19-oic acid was established by spectroscopic methods, especially two dimensional NMR techniques.
Ring-Opening of Cyclic Anhydrides using Ionic Liquids
Authors: Jiang Dong , Wang Yuan Yuan , Xu Yan Nan , Dai Li Yi
Published: December 2009

Four novel Brønsted acidic ionic liquids with two different acid sites on the imidazolium cations were synthesised and employed as catalysts and solvents for the ring-opening of cyclic anhydrides to synthesise half-esters. The results showed that these novel Brønsted acidic ionic liquids were efficient and recyclable. Good yields, short reaction times and mild reaction conditions were achieved.
An Alternative Route for the Synthesis of 2,3,4,5-tetramethoxytoluene
Authors: Vera William J. , Chinea Kimberly , Banerjee Ajoy K.
Published: December 2009

The transformation of the commercially available 2,3.4-trimethoxybenzaldehyde to 2,3,4,5-tetramethoxytoluene using a Dakin reaction to insert the extra oxygen, formylation, reduction and methylation of the phenolic hydroxyl group is described.
Synthesis, Spectroscopic and Crystal Structure Analysis of 2-amino-5,5-dimethyl-7-oxo-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile and -3-carboxamide
Authors: Begum Noor Shahina , Vasundhara D.E. , Lamani R. S. , Hegde V.S. , Khazi I.M.
Published: December 2009

The preparation of 2-amino-5,5-dimethyl-7-oxo-4,5,6,7-tetrahydro-1-benzophiophene-3-carboxamide via the intermediate 2-amino-5,5-dimethyl-7-oxo-4,5,6,7-tetrahydro-1-benzophiophene-3-carbonitrile is described, along with details of the crystal structure analysis of both compound.
Facile Polyethylene Glycol (PEG-400) Promoted Synthesis of Some New Heteryl (E)-styryl Sulfones
Authors: Guravaiah Nalajam , Rao Vedula Rajeswar
Published: December 2009

An efficient and convenient synthesis of heteryl ( E)-styryl sulfones is described. Reaction of an 3-(2-bromoacetyl)coumarin with sodium ( E)-styrenesulfinates yields the corresponding styryl sulfones promoted by polyethylene glycol (PEG-400) as an efficient reaction medium at room temperature
Synthesis of polymethyl substituted [2.2]metaparacyclophanes and their Lewis-acid induced isomerisation to [2.2]metacyclophanes
Authors: Shimizu Tomoe , Hita Katsuhiro , Paudel Arjun , Tanaka Junnji , Yamato Takehiko
Published: December 2009

The preparation of polymethyl substituted [2.2]metaparacyclophanes using sulfur method and the X-ray structure determination of 4,5,6,8,12,13,15,16-octamethyl[2.2]metaparacyclophane are described. AlCl3-MeNO2-catalysed trans- tert-butylation of 5- tert-butyl-8,12,13,15,16-pentamethyl[2.2]metaparacyclophane in benzene led to isomerisation reaction to afford the strainless 8,12,13,14,16-pentamethyl[2.2]metacyclophane in 85% yield along with tert-butylbenzene.
Synthesis of Flavonoid 7-O-β-D-glycosides by Phase Transfer Catalysis
Authors: Wu Zheng , Jiang Ling , Chen He , Wang Qiu-an
Published: December 2009

Six flavonoid 7- O-β-D-glycosides 1a-3a and 1b–3b were synthesised from the flavones 7a and 7b by glycosidation and deacetylation with the corresponding α-acetylglycosyl bromides. 7a and 7b were prepared in high yield by an improved Baker-Venkataraman rearrangement using 2, 4-dihydroxyacetophenone as starting material and tetrabutylammonium bromide (TBAB) as a phase transfer catalyst. The glycosidation procedure was modified by using anhydrous K2CO3 in a solvent mixture of DMF/acetone (3:2v/v) and TBAB as a phase transfer catalyst.
The Synthesis and Anticancer Activities of Peptide 5-fluorouracil Derivatives
Authors: Yan Xiaowei , Hu Maolin , Miao Qian , Wang Shun , Zhao Kejian
Published: December 2009

A new series of peptide 5-fluorouracil derivatives was designed and synthesised in order to test in vitro anticancer activities. The results indicated that peptide 5-fluorouracil derivatives possessed anticancer activities against human HL-60 and Bel-7402 cell lines. The structures of the compounds were determined by means of 1H NMR, 13C NMR, IR, mass spectra and elemental analyses.
A Green Method for the Synthesis of Novel benzo[b]pyran Derivatives in an Ionic Liquid
Authors: Wang Xiang-Shan , Wu Jian-Rong , Li Qing , Tu Shu-Jiang
Published: December 2009

A series of novel 2-amino-5,6,7,8-tetrahydro-4,7,7-trimethyl-5-oxo-4-aryl-4 H-benzo[ b]pyran-3-carbonitriles was obtained from the reaction of 2-(1-arylethylidene)malononitrile and 5,5-dimethylcyclohexane-1,3-dione in an ionic liquid at 90°C. This method had the advantages of operational simplicity, mild reaction conditions and an environmentally benign procedure.
Reactions of 2-amino-4,5,6,7-tetrahydro[1]benzothiophene-3-carbonitrile and 6-amino-1,4-dihydro-3-methyl-1,4-diphenylpyrano[2,3-c]pyrazole-5-carbonitrile with substituted benzylidenemalononitriles, α,β-acetylenic esters and ketones
Authors: Youssef Ahmed Said Ahmed
Published: December 2009

Reactions of 2-amino-4,5,6,7-tetrahydro[1]benzothiophene-3-carbonitrile (1a) with substituted benzylidenemalononitriles gave 4-amino-2-(1-cyano-2-arylvinyl)benzothieno[2,3- d]pyrimidine derivatives (3) as ( E,Z)-mixtures and in one case (2c) as separated ( Z)- and ( E)-isomers. Similar treatment of 6-amino-1,4-dihydro-3-methyl-1,4-diphenyl-pyrano[2,3- c]pyrazole-5-carbonitrile (4) yielded similarly-formed pyrazolopyranopyrimidine derivatives (5a, b) as ( Z)-and ( E)-stereoisomers. Attempted acetylation of the aminobenzothienopyrimidines resulted in degradation of the pyrimidine ring and the formation of N-(3-cyano-4,5,6,7-tetrahydro[1]benzothien-2-yl)acetamide (1b). Treatment of 4 with acetylenic esters and ketones (6a-d) afforded the ( Z)-substituted enaminopyrano[2,3- c]pyrazole derivatives. Reacting 1a with aroyl phenyl acetylenes gave by Michael addition the enamino-ketones (8a-c).
A New Norditerpenoid Alkaloid from Delphinium Densiflorum
Authors: Sun Jian-Yun , Li Tian-Cheng
Published: December 2009

A new norditerpenoid alkaloid delphidenine was isolated from the EtOH extract of the whole plants of Delphinium densiflorum. Its structure was established by extensive application of spectroscopic methods, including IR, HR-ESI-MS, 1D and 2D NMR spectroscopy.
Synthesis and Recognition Properties of Two Novel Concave Molecules Based on Glycoluril
Authors: Shuai Wang , An-Xin Wu , Neng-Fang She
Published: December 2009

Two new concave fluorescent molecular clips based on diethoxycarbonyl glycoluril and diphenyl acetylene units have been synthesised by introducing the fluorophores into the receptor. Their recognition properties toward various metal ions were studied by fluorescence spectroscopy. The results demonstrate that they can selectively bind Fe3+ with fluorescence quenching.
Four-Component Reaction of Isocyanides, Acetylenic Esters, and Carboxylic Acids for the Synthesis of Functionalised 2,5-diaminofurans
Authors: Anary-Abbasinejad Mohammad , Rasekh Maryam , Anaraki-Ardakani Hossein
Published: December 2009

An improved four-component reaction of isocyanides is described. The reaction between two equivalents of an isocyanide, dialkyl acetylenedicarboxylates and aliphatic carboxylic acids at room temperature leads to 2,5-diaminofuran derivatives in good yields.
Solid-phase synthesis of aryl vinyl ethers based on polystyrene-supported β-phenylselenoethanol
Authors: Zhang Jia-Li , Sheng Shou-Ri , Liu Xue , Lin Shu-Ying
Published: December 2009

A novel facile solid-phase organic synthesis of aryl vinyl ethers by reaction of polystyrene-supported β-phenylselenoethanol with phenols under Mitsunobu conditions and subsequent oxidation-elimination with 30% hydrogen peroxide has been developed. The advantages of this method include straightforward operation, lack of odour, good yield and high purity of the products.
Synthesis of Functionalised Phosphonates or Phosphoranes by Reaction between Trialkyl Phosphites or Triphenylphosphine, Dimethyl Acetylenedicarboxylate and Aldehyde Ethyl Carbazones
Authors: Anary-Abbasinejad Mohammad , Mosslemin Mohammad H. , Hassanabadi Alireza , Dehghan Alimohammad
Published: December 2009

Protonation of the reactive intermediate produced from the reaction between trialkyl phosphites and dimethyl acetylenedicarboxylate by ethyl carbazones of aromatic aldehydes following by conjugate addition of the anion of ethyl carbazone on the phosphonium salt intermediate leads to functionalised phosphonates in good yields. Triphenylphosphine also reacted with dimethyl acetylenedicarboxylate and ethyl carbazones to produce functionalised phosphoranes in good yields.
Synthesis of 8-methyl[2.2]metacyclophanes and their charge-transfer complexes with tetracyanoethylene
Authors: Shimizu Tomoe , Hita Katsuhiro , Rahman Shofiur , Yamato Takehiko
Published: December 2009

The regioselective 1:1 charge-transfer band of 13-substituted 8-methyl[2.2]metacyclophanes with tetracyanoethylene in CH2Cl2, attributable to the 8-methyl substituted benzene-site complex, are observed in the field of 556–605 nm, which is strongly affected by π-electron density of the opposite aromatic ring.
ipso-Acylation of 5,13-di-tert-butyl-8,16-dimethyl[2.2]metacyclophane with acid anhydrides: Through-Space Electronic Interaction among the Two Benzene Rings
Authors: Shimizu Tomoe , Paudel Arjun , Yamato Takehiko
Published: December 2009

Acylation of 5,13-di- tert-butyl-8,16-dimethyl[2.2]metacyclophane with acid anhydrides led to mono- ipso-acylation at the tert-butyl group to give 5-acyl-13- tert-butyl-8,16-dimethyl[2.2]metacyclophanes, from which the second electrophilic substitition with acid anhydrides can be strongly suppressed because of deactivation of the second aromatic ring by acyl group introduced by the through-space electronic interaction.
CuX2 (X = Cl, Br) as Catalysts for Pechmann Reaction: Synthesis of 4-substituted Coumarins
Authors: Wang Yi , Xu Feng , Tian You-Ping , Li Hui-Li , Wang Jian-Jun
Published: December 2009

CuX2 (X=Cl, Br) are found to be efficient catalysts (10 mol%) for the Pechmann condensation reaction of phenols and β-ketoesters to give 4-substituted coumarins under solvent-free conditions. The yields of coumarin derivatives obtained via this new protocol, were equal or higher than those using the conventional method and the reaction time was reduced to a few minutes.
EPR Studies on Carboxylic Esters. Part 20. EPR Spectra and Spin Densities in Radical Anions of Isocoumarin, Benzocoumarin and their Sulfur Analogues
Authors: Voss Jürgen , Kupczik Gabriele , Stahncke Heidi
Published: December 2009

The radical anions of isocoumarin, benzocoumarin and the six corresponding sulfur analogues have been generated by internal electroreduction and studied by EPR spectrosopy. The spin density distributions have been evaluated from the proton hyperfine structure coupling constants and by MO calculations. They are discussed with respect to the spin density distributions in related radical anions.
Synthesis of Novel Schiff Bases from the Reaction of 3-O-methyl-4, 6-O-benzylidene-β-D-glucopyranosylamine with substituted aldehydes
Authors: Shen Chao , Zhao Qing , Zheng Hui , Zhang Pengfei
Published: December 2009

The synthesis of novel sugar derived Schiff base derivatives from reaction of 3-O-methyl-4, 6-O-benzylidene-β-D-glucopyranosylamine with several substituted aldehydes is described.
Behaviour of the uranyl (UO22+) ion in different strongly acidic media: Characterisation of UO22+ in common acids by electronic absorption spectroscopy
Authors: Sun Xiaoping , Samples Clayton , Daia Kristopher , Meyers Matthew , Bumgarner Michael
Published: December 2009

The linear uranyl (UO22+) ion has been characterised by electronic absorption spectroscopy in the media of four highly concentrated acids: sulfuric, nitric, acetic, and hydrochloric acids. In sulfuric acid, the magnitude of splitting (cm1) of the vibronic peaks in the UO22+ spectra increased linearly as molar concentration of the acid increased from zero to 18 M. Such an unprecedented spectral progression has been attributed to the high concentrations of sulfuric acid reducing the extent of coordination of water molecules to the central uranium atom of UO22+. This is believed to reduce the electron density in the uranium valence shell and decrease the electrostatic repulsion between the uranium and oxygen valence shells, making the U=O bonds stronger. It results in the observed increase in splitting of the vibronic peaks. In nitric acid, a completely different spectral feature of uranyl was observed. First, as molar concentration of nitric acid increased, the vibronic structure in the UO22+ spectra disappeared gradually and the absorption band became continuous at 6 M. As the acid concentration further increased, vibronic lines were resolved in the lower-energy side of the spectra. The higher-energy side remained continuous with no vibronic structure observed. The convergence limit (cm1), the borderline between vibronic peaks in the lower-energy side and a continuous band in the higher-energy side, decreased linearly as the molarity of nitric acid increased from 8 M to 16 M. All this shows that nitric acid, with involvement of its conjugate nitrate anion, has made UO22+ dissociative beyond the convergence limit of its excited state. In acetic acid, as the molar concentration of the acid increased from zero to 17.5 M, the UO22+ spectra exhibited three-stages of progression due to a predominating coordination of a carboxyl group to UO22+ ([HOAc] = 0–9 M), dissociation of UO22+ at the convergence limit of its excited state ([HOAc] = 10–14 M), and formation of an undissociative excited state for UO22+ ([HOAc] = 15–17.5 M). In hydrochloric acid, UO22+ exhibited a comparable spectral feature to that observed in nitric and acetic acids due to a predominating coordination of the chloride anion to UO22+.
A Straightforward Expeditious synthesis of 5-nitrobenzo[b]thiophene-2-carbaldehyde
Authors: Wei Hongtao , Sun Min , Ji Min
Published: December 2009

A high yielding one-pot synthesis of 5-nitrobenzo[b]thiophene-2-carbaldehyde is reported using the readily available, cheap starting material 2,5-dihydroxy-1,4-dithiane and 2-chloro-5-nitrobenzaldehyde.
One-pot synthesis of (E)-α-chloro-α,β-unsaturated esters
Authors: Karama Usama
Published: December 2009

Chlorination of a phosphonate anion derived in situ from methyl bis(2,2,2-trifluoroethoxy)phosphonoacetate 2 followed by the addition of aldehydes constitutes a stereoselective single flask procedure for the preparation of E-configured α-chloro-α,β-unsaturated esters.
Preparation of Some heterocyclic enones and ynones by isomerisation of the propargylic alcohols
Authors: Erenler Ramazan , Uno Masaharu , Goud Thirumani Venkateshwar , Biellmann Jean-François
Published: December 2009

The propargylic alcohols were synthesised by treatment of aldehydes with substituted acetylenes. The conversion of propargylic alcohols to propynones and propenones takes place with pyridine hydrochloride in methanol at room temperature. In presence of pyridinium triflate and p-toluenesulfonate the propynone was the only product isolated in the isomerisation of alcohol. The silylated propenone undergoes with cyclopentadiene a Diels–Alder cycloaddition to give ketone whose skeleton is related to that of quinine.
Synthesis of 5-tert-butyl-8,12,14-trimethyl- and 5-tert-butyl-8,12,14,16-tetramethyl[2.2]metacyclophane and their treatment with Lewis acids in benzene
Authors: Shimizu Tomoe , Hida Katsuhiko , Yamato Takehiko
Published: December 2009

Treatment of 5- tert-butyl-8,12,14,16-tetramethyl[2.2]MCP with AlCl3-MeNO2 in benzene led to trans- tert-butylation to afford 8,12,14,16-tetramethyl[2.2]MCP in good yield along with tert-butylbenzene. On the other hand, the same treatment of 5- tert-butyl-8,12,14-trimethyl[2.2]MCP led to transannular cyclisation reaction and isomerisation reaction to afford the corresponding strainless 2- tert-butyl-3a,6,8-trimethyl-3,3a,4,5,9,10-hexahydropyrene in good yield.
Chromone Studies. Part 17. Tricyclic Scaffolds from Reactions of chromone-3-carbaldehydes and methyl vinyl ketone under Baylis–Hillman conditions
Authors: Molefe Duduzile M. , Ganto Mlungiseleli M. , Lobb Kevin A. , Kaye Perry T.
Published: December 2009

Reaction of a series of chromone-3-carbaldehydes with methyl vinyl ketone under Baylis–Hillman conditions, using 3-hydroxyquinuclidine in chloroform or DABCO in 1-methyl-2-pyrrolidinone, affords unprecedented tricylic chromone derivatives which, depending on the conditions, may be accompanied by the normal Baylis–Hillman products or their respective tricyclic dimers.
Ionic liquid promoted and mediated green preparation of arylbispyranylmethane and pyran derivatives and their hybrid with a pyrimidine nucleoside
Authors: Zhang Xinying , Qu Yingying , Fan Xuesen , Wang Xia , Wang Jianji
Published: December 2009

The utilisation of an ionic liquid-[bmim][BF4] as both reaction medium and promoter for the reaction between aldehyde and 4-hydroxy-6-methylpyran-2-one is described. Without any added catalyst, this reaction was realised efficiently to give arylbispyranylmethane derivatives in high yields. Alternatively, when this reaction was carried out in the presence of acetic anhydride, fused pyran derivatives were obtained. These two novel procedures have advantages such as an environmentally benign nature, high efficiency, simple operation process and mild reaction conditions. As an application, these procedures were used in the preparation of novel 5-substituted pyrimidine nucleoside derivatives with potential antiviral activities.
Raney Ni-Al alloy mediated hydrodehalogenation and aromatic ring hydrogenation of halogenated phenols in aqueous medium
Authors: Liu Guo-Bin , Zhao Hong-Yun , Zhang Jie , Thiemann Thies
Published: December 2009

Raney Ni-Al alloy in a dilute aqueous alkaline solution has been shown to be a very powerful reducing agent and is highly effective for the reductive dehalogenation of polyhalogenated phenols and aromatic ring hydrogenation of phenols to the corresponding cyclohexanols.
A practical synthesis of 1-cyano-4,5-dimethoxybenzocyclobutene
Authors: Zhao Sheng Yin , Liang Hong Yu , Shao Zhi Yu , Chen Rui
Published: December 2009

A practical synthesis of 1-cyano-4,5-dimethoxybenzocyclobutene, the key intermediate of Ivabradine, was developed in four or five steps using two different routes. 2-Bromo-4,5-dimethoxyhydrocinnamonitrile was produced via the condensation of 2-bromo-4,5-dimethoxybenzaldehyde with acetonitrile or cyanoacetic acid and reduction by NaBH4. Cyclisation gave 1-cyano-4,5-dimethoxybenzocyclobutene. Overall yields of the routes A and B were 30% and 37% respectively. Route B is a short and simple route, permitting the synthesis of 1-cyano-4,5-dimethoxybenzocyclobutene on a large scale.
Synthesis of novel pyridazinyl benzimidazole, benzothiazole and benzoxazole of Expected Anti-Inflammatory Activity
Authors: Refaat Hanan M. , Khalil Omneya M. , Abuel-Maaty Suzan M.
Published: December 2009

In this study, a novel series of 6-oxopyridazinyl benzazoles and 3, 6-dioxopyridazinyl benzazoles were prepared from the starting compounds, 2-hydrazinobenzimidazole, 2-hydrazinobenzothiazole and 2-hydrazinobenzoxazole by reaction with butyric acid derivatives and cyclic anhydrides respectively. The structures of the new compounds were confirmed by elemental analysis as well as 1H NMR, IR and MS data. Some of the newly prepared compounds were subjected to evaluation for their anti-inflammatory activity using carrageenan induced paw edema at dose 100 mg kg−1 using indomethacin as a reference standard and were found to be bioactive.
An efficient synthesis of phenyl-substituted dibenzonaphthyridines
Authors: Manoj Manickam , Prasad Karnam Jayaramapillai Rajendra
Published: December 2009

A one-pot synthesis of 9-chloro-6-methyl-7-phenyldibenzo[ b,h][1,6]naphthyridines from 4-chloro-2-methylquinolines is reported. Since the yield of the dibenzonaphthyridine was low, in an alternative method the title compounds were prepared from the 4-chloro-2-methylquinolines via 2-methyl-4-[(4-chlorophenyl)amino]quinolines as intermediates, which provided improved yields.
Cu(OTf)2-catalysed synthesis of structurally novel bicyclic 1,3-oxazines via condensation-dehydrazinative ring transformation cascades
Authors: Yadav Lal Dhar Singh , Rai Ankita , Rai Vijai Kumar , Awasthi Chhama
Published: December 2009

The Cu(OTf)2-catalysed expeditious synthesis of 1,3-oxazin-2-ones(thiones) from unprotected D-glucose and D-xylose in excellent yields is reported. Cu(OTf)2 plays a dual role of a Lewis acid and an oxidant for dehydrazination, which is the cornerstone in the present investigation. The 1,3-oxazin-2-ones(thiones) serve as synthons for diversity oriented synthesis of structurally distinct bicyclic 1,3-oxazin-2-ones(thiones), when subjected to Malaprade reaction, followed by Cu(OTf)2-catalysed cyclisation with an appropriate traditional reagent such as phenylhydrazine, amidines, hydroxylamine, or semi(thiosemi)carbazide.
Variation of grain growth of wheat cultivars
Authors: Adhikary SK , Alam MZ , Paul NK
Published: December 2009

An experiment was carried out to study the grain growth pattern of wheat (Triticum aestivum L.) cultivars and to find out association and linear regression of spike weight and grain weight with time. Spike characters indicated that cultivar differences were significant in all the cases with a few exceptions. Linear regression and correlation coefficients revealed that the association between both spike weight and grain weight with time were highly positively significant among the cultivars but their regression coefficients were non- significant. Key Words: Grain growth, correlation, regression, wheat. DOI: 10.3329/bjar.v34i3.3960 Bangladesh J. Agril. Res. 34(3) : 351-359, September 2009
In vitro organogenesis of Latiraj
Authors: Hossain MJ
Published: December 2009

In vitro organogenesis of a lowland species of Colocasia esculenta sp. esculenta L. cv. Latiraj was assessed in relation to explant types (meristem, parenchymatous tissues and storage tissues); three levels of each of NAA, BAP, Kn, and 2,4-D; four culture environments, such as 16h 3000 lux light intensity, 24±2°C, 24h dark + 24±2°C, 24h dark + 30±3°C, and 12h diffuse light + 30±3°C. Only isolated meristem and parenchymatous tissues regenerated plants with various degree of morphogenic intensity with different combinations of growth regulators. Meristem under both light and dark and at 24±2°C with upto Kn 3.0 + NAA 3.0 showed proliferation with poor rate of growth, while Kn 1.0+ NAA 3.0 had comparatively good response. The parenchymatous tissues with above environments responded very quickly with varying degree of growth intensity. Kn+2,4-D was found least effective on regeneration from any explants. NAA and BAP had an effect on proliferation of shoot, root and other growth characters from both meristem and parenchymatous tissues under both light and dark conditions at 24±2°C. This combination showed a very high degree of proliferation and caused callusing to some extent when cultured at dark which developed shoots and roots quickly after transferring to light. Except NAA+BAP, no other combination formed stolon. The white colour storage tissues after 30 days turned yellowish followed by greenish with shiny pimples after 50 days indicating that the cultures with protocorm may be developed. Almost all the cultures under high temperature environments (30±3°C) neither survived nor proliferated. The meristems also died within 15-20 days, while others within 25-30 days. Thus, a temperature range of 30±3°C was in no way suitable for in vitro culture of lowland species of Colocasia esculenta cv. Latiraj. Key Words: Organogenesis, auxins, cytokinins, meristem, parenchymatous tissues, storage tissues, Colocasia esculenta L. cv. Latiraj. DOI: 10.3329/bjar.v34i3.3963 Bangladesh J. Agril. Res. 34(3) : 385-394, September 2009
In vitro callus initiation and regeneration of potato
Authors: Haque AU , Samad MA Ehsanul , Shapla TL
Published: December 2009

The first experiment involving different explants and concentrations of 2,4-D and kinetin showed highly significant differences for length and weight of callus formed except interaction of callus weight. Leaf explant appeared to be best of all for callus length and weight when 1.0 mg/L 2,4-D + 0.25 mg/L kinetin concentration was used. Similarly, different explants versus different concentrations of BAP/GA3/IAA showed significant differences for shoot length and leaf number per plantlet and also for root length. However, interaction term confirmed node and node/internode explants produced better results in shoot length and number of leaves per plantlet when concentrations 1 .0 mg/L BAP + 0.1 mg/L GA3 and 1.0 mg/L BAP + 0.2 mg/L GA3, 1.0 mg/L BAP + 0.4 mg/L GA3, respectively, were used. Similarly, internode explants produced better results for root length after 21 days plantlet-1 when concentration of 1.0 mg/L IAA + 0.25 mg/L GA3 was used. Shoot tip explants also produced better results in root length after 28 days plantlet-1 when concentrations 1.0 mg/L IAA + 0.25 mg/L GA3 were used. Key Words: In vitro, callus initiation, regeneration, potato. DOI: 10.3329/bjar.v34i3.3971 Bangladesh J. Agril. Res. 34(3) : 449-456, September 2009
Effect of sowing time and spacing on lettuce seed production in hilly region
Authors: Firoz ZA , Alam MS , Uddin MS , Khatun SA
Published: December 2009

DOI: 10.3329/bjar.v34i3.3980 Bangladesh J. Agril. Res. 34(3) : 531-536, September 2009
Trace elements status in type 2 diabetes
Authors: Hussain Fatma , Maan Mohammad Arif , Sheikh Munir Ahmed , Nawaz Haq , Jamil Amer
Published: December 2009

Background: The metabolism of several trace elements has been reported to alter in diabetes mellitus and these elements might have specific roles in the pathogenesis and progress of this disease. Objective: The aim of the present study was to investigate serum levels of copper, zinc, chromium, magnesium and manganese in type 2 diabetic patients and their possible association with age, glycemic status and duration of diabetes. Methodology: The comparative study included 116 type 2 diabetic patients and 40 non-diabetic subjects. Fasting plasma glucose and HbA1c were determined by the glucose oxidase method and affinity chromatography respectively. The element concentrations were measured by means of an atomic absorption spectrophotometer after microwave-induced acid digestion. Results: Mean (±SD) Mg and Zn levels were significantly reduced in blood samples of diabetic patients as compared to control subjects (p<0.0001-<0.05). The alterations observed in serum levels of copper and manganese was not significant among diabetic and normal subjects. Glycemic status, duration of diabetes and age did not effect the trace elements concentrations. Conclusion: The results confirm that deficiency and efficiency of some essential trace metals may play a role in the development of diabetes mellitus. Key words: Trace elements, glycemic status, type 2 diabetes. DOI: 10.3329/bjms.v8i3.3983 Bangladesh Journal of Medical Sciences Vol.8(3) 2009 p52-56
A Study of the Crystallization, Melting, and Foaming Behaviors of Polylactic Acid in Compressed CO2
Authors: Zhai Wentao , Ko Yoorim , Zhu Wenli , Wong Anson , Park Chul B.
Published: December 2009

The crystallization and melting behaviors of linear polylactic acid (PLA) treated by compressed CO2 was investigated. The isothermal crystallization test indicated that while PLA exhibited very low crystallization kinetics under atmospheric pressure, CO2 exposure significantly increased PLA’s crystallization rate; a high crystallinity of 16.5% was achieved after CO2 treatment for only 1 min at 100 °C and 6.89 MPa. One melting peak could be found in the DSC curve, and this exhibited a slight dependency on treatment times, temperatures, and pressures. PLA samples tended to foam during the gas release process, and a foaming window as a function of time and temperature was established. Based on the foaming window, crystallinity, and cell morphology, it was found that foaming clearly reduced the needed time for PLA’s crystallization equilibrium.
Fabrication and Properties of Carbon Fibers
Authors: Huang Xiaosong
Published: December 2009

This paper reviews the research and development activities conducted over the past few decades on carbon fibers. The two most important precursors in the carbon fiber industry are polyacrylonitrile (PAN) and mesophase pitch (MP). The structure and composition of the precursor affect the properties of the resultant carbon fibers significantly. Although the essential processes for carbon fiber production are similar, different precursors require different processing conditions in order to achieve improved performance. The research efforts on process optimization are discussed in this review. The review also attempts to cover the research on other precursor materials developed mainly for the purpose of cost reduction.
Protecting-Group-Free Synthesis of 2-Deoxy-Aza-Sugars
Authors: Dangerfield Emma Marie , Plunkett Catherine Heather , Stocker Bridget Louise , Timmer Mattie Simon Maria
Published: December 2009

The protecting-group-free asymmetric synthesis of 1,2,4-trideoxy-1,4-imino-L-xylitol is readily achieved in five steps from 2-deoxy-D-ribose and with an overall yield of 48%. Key in this synthesis is the application of our recently developed Vasella-reductive amination and carbamate annulation methodologies to the synthesis of 2-deoxy-aza-sugars. The carbamate annulation occurred with excellent yield and diastereoselectively (>20:1 d.r.), in favour of the 3,4-cis isomer.
A Chalcone Glycoside from the Fruits of Sorbus commixta Hedl.
Authors: Bhatt Lok Ranjan , Bae Moon Sung , Kim Bo Mi , Oh Gi-Su , Chai Kyu Yun
Published: December 2009

Sorbus commixta Hedl. (Rosaceae) has been traditionally used in oriental countries for the treatment of asthma and other bronchial disorders. In this study, a chalcone glycoside was isolated from the ethyl acetate extract of the fruits of this plant. The compound was identified as neosakuranin based on the spectroscopic analysis and comparion with literature data. This is the first report of isolation of neosakuranin from Sorbus commixta.
Numerical Analysis of Dynamic Effects of a Nonlinear Vibro-Impact Process for Enhancing the Reliability of Contact-Type MEMS Devices
Authors: Ostasevicius Vytautas , Gaidys Rimvydas , Dauksevicius Rolanas
Published: December 2009

This paper reports on numerical modeling and simulation of a generalized contact-type MEMS device having large potential in various micro-sensor/actuator applications, which are currently limited because of detrimental effects of the contact bounce phenomenon that is still not fully explained and requires comprehensive treatment. The proposed 2-D finite element model encompasses cantilever microstructures operating in a vacuum and impacting on a viscoelastic support. The presented numerical analysis focuses on the first three flexural vibration modes and their influence on dynamic characteristics. Simulation results demonstrate the possibility to use higher modes and their particular points for enhancing MEMS performance and reliability through reduction of vibro-impact process duration.