Synthesis and Crystal Structure of 9-Pyridyl-1,8-dioxo-2,3,4,5,6,7-hexahydroxanthene

1 INTRODUCTION The Koevenagel condensation catalyzed by bases or Lewis acid has been the subject of many synthetic applications since its discovery[1] although the pre- sence of catalyst is not always indispensable[2]. Mo- reover, the reaction of aromatic aldehyde with 1,3- cyclohexanedione under different conditions afforded different products[3～6]. In continuing efforts for the application of 1,3-cyclohexanedione derivatives to construct new heterocycles with biological activi- ties[7…     

Crystal Structure of D-Valine at the Temperature of 293, 270, 223 and 173K

1 INTRODUCTION D-amino acids are universally present and play different biological roles in various organisms in- cluding those in the human body. Milton[1] has shown that the D and L forms of the enzyme HIV-1 protease were equally affected by the achiral inhi- bitor but displayed reciprocal chiral specificity in their biochemical interactions. D-proteins may also be nonimmunogenic. Senility and some diseases are related to D-amino acids, such as renal disease[2], Alzheimer disease[3…     

Syntheses of Binuclear Copper(I) Complexes Containing Benzimidazole

1 INTRODUCTION Procedures to synthesize copper(I) complexes are of great interest due to the diversity of products resulting from almost the same methodology. It has been long known that four-electron-donordipho- sphine compounds Ph2P(CH2)nPPh2 are excellent bi- dentate ligands[1, 2]. The chelating tendency of bis- (diphenylphosphino) methane is one of the dipho- sphine ligands most suitable to lock two metal atoms together in close proximity[3]. Many examples of bi- or polynuclear com…     

Hydrothermal Assembly and Structural Characterization of a Novel 3D Coordination Polymer: [Cd_2Zn(BTC)_2(H_2O)_4]_n·2nH_2O

1INTRODUCTIONThehydrothermalsynthesisofmetalsaltsofaro-maticpolycarboxylicacidisattractinginterestinthefieldofcrystalengineeringasaconsequenceoftheirnovelstructuresandpropertiessuchasporosityandmagneticinteractionsbetweenparamagneticmetal-ions[1~7].1,3,5-Benzenetricarboxylicacid(H3-BTC)hasreceivedconsiderableattentionasatridentatearomaticpolycarboxylicligandcapableofformingcoordinationpolymers.Manyscientistshavesuc-ceededinsynthesizingvarietyofporouscoordina-tionpolymerswithhighdimension…     

Crystal Structure of a Linear Ag(I) Complex with Niflumic Acid and Its Fluorescent Property

1 INTRODUCTION Niflumic acid (2-[3-(trifluoromethyl) phenyl] amino nicotinic acid, HNifa) is an organic fluoro compound used in the preparation of ‘Donalgin’ as the active substance. In medicine, HNifa has been widely used as a non-steroidal anti-inflammatory analgetic drug[1]. The extensive application of this preparation in medical practice has attracted much interest in other various biological fields such as the determination in serum, urine[2～4], and coordination behaviors with …     

Synthesis and Crystal Structure of 6—Bromo—piperonal—dimethyl—acetal

1 INTRODUCTION 6-Bromo-piperonal-dimethyl-acetal is an intermediate used for the synthesis of natural products, such as podophyllotoxin[1] and the related compounds[2～6] due to the useful biological activities associated with some of its derivatives[7, 8]. In particular, glycoside derivatives of 4?dimethyl- 4-epipodophyllotoxin have been used in cancer chemotherapy[9, 10]. The title compound has been synthesized from raw material piperonal, after bromo substitution and acetal protection…     

A Novel Platinum（Ⅳ） Halide Anion as Ethyl-triphenylphosphenonium Salt： Synthetic, Structural and Theoretical Study

1 INTRODUCTION The importance of metal ions in nucleic acid and other biologic processes has stimulated considerable research interest in the area of metal interactions with nuclei acid constituents[1, 2] due to the discovery that some platinum compounds, especially cis-Pt (NH3)2- Cl2, exhibit carcinostatic properties[3]. This has led to an increased research activity in the chemistry and structures of platinum complexes containing novel or- ganic ligands. And crystal engineering has its…     

Electron Ionization Mass Spectrometry of Some Ferrocenyl Thia-crown Ethers

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Synthesis and Crystal Structure of 1,3-Trans-1,4-cis- 3,4-di(4-bromophenyl)-1',2',3'-trihydro-1-hydroxy- benzo[g]bicyclo[3.3]octane-2-spiro-2'-indene-1'-one

1 INTRODUCTION Low-valent titanium reagents have exceedinglyhigh abilities to promote reductive coupling of car-bonyl compounds and they are attracting increasinginterest in organic synthesis[1]. Many other func-tional groups can also be coupled[2~8]. Recently, wehave reported some intermolecular reductive cou-pling reactions[9~12] and some new intramolecular re-ductive coupling reactions[13~16] induced by low-va-lent titanium reagents. The spiro[4.4]nonane skeleton has been found inmany…     

Structural and Spectroscopic Properties of Linear Carbon Chains NC2nN and HC2n＋1N （n = 1- 10）

1 INTRODUCTION Carbon-chain species are widely present in the interstellar medium as possible carriers of the diffuse interstellar bands. They play an important role in diverse chemical processes and nanoscience as intermediates and building units. Because of their high reactivity, bare carbon chains are readily termi- nated by a wide variety of atoms, forming XCn or XCnX linear clusters[1]. During the past decade, lots of theoretical spectra of different carbon chain systems have been …