Formation of Benzyl Oxazole, A Competitive Path with the Classical Bishler-Napieralski Reaction

1,2,3,4-tetrahydroisoquinoline-3-carboxylic acids (TIC) are of considerable interest due to their biological activity and as an important structural element in several important alkaloids and other medically useful products1. Moreover, TIC is a phenylalanine analogue in which the dihedral angle is limited to a very small range because of its bicyclic nature2. In connection with the design of topographically constrained peptides, TIC has been utilized in several instance as a replacement o…     

Hydrothermal Synthesis and Structure of[{Mo_8V_4O_(36)(VO_4)(VO)_2}n]~(7n-)Bi-capped α-Keggin Fragments Linked to a Chain

The title compound, (H2en)3H3O{Mo8V4O36(VO4) (VO)2} ?4H2O, was hydrothermally synthesized and structurally characterized by means of IR, ESR spectrum and single crystal X-ray diffraction. It crystallized in a monoclinic system with space group P21/c, a=1. 980 4(4) nm, 6=2. 063 4(4) nm, c=l. 192 0(2) nm, =94. 76(3)?and deep black colour. The compound contains V-centered bi-capped a-Keggin fragments {Mo8V7O42} that are linked together by edge-shared units V O5 via V桹梀 bonds, forming a chain.     

On Vector Helmholtz Equation with a Coupling Boundary Condition

The Helmholtz equation is sometimes supplemented by conditions that include the specification of the boundary value of the divergence of the unknown.In this paper, we study the vector Helmholtz problem in domains of both C~(1,1)and Lipschitz.We es- tablish a rigorous variational analysis such as equivalence,existence and uniqueness. And we propose finite element approximations based on the uncoupled solutions.Fi- nally we present a convergence analysis and error estimates.     

A New Diterpene Glycoside from Isodon forrestii

The genus Isodon has been shown to be a rich source of diterpenes, especially the highly oxidized ent-kaurene diterpenoids with various biological activities1-3. The chemical constituents of Isodon forrestii was reported by Yun Long Xu et al.4. We have investigated the titled plant collected in another place, from the 70% acetone extract of the aerial parts of I. forrestii, seven compounds including a new diterpene glycoside 1 were isolated by a combination of silica gel, preparative TLC an…     

Peduncin, A New Indole Alkaloid from Pueraria peduncualris

Pueraria peduncularis (Grah. ex Benth.) Benth. is a plant of Leguminosae which grows in the southwest of China. Different from other plants of Pueraria, it could not be used as a medicine due to its toxicity1. In order to use the Pueraria plants safer, we studied the constituents of P. peduncularis. Previous phytochemical studies of an n-BuOH extract afforded three triterpenoid saponins2-3. The continuing investigation on CHCl3 extract led to the isolation of a new indole alkaloid. …     

Synthesis and DNA Cleavage Studies of 2,6-Dimethoxyhydroquinone-3-Mercaptoacetic Acid Conjugates

In previous paper and work, we reported the synthesis and cytotoxicity studies of a novel series of short chain peptide conjugates of the cytotoxic agent 2, 6-dimethoxyhydro -quinone-3-mercaptoacetic acid1 (DMQ-MA). The DMQ-MA is a derivative of 2,6-dimethoxybenzoquinone, which is a natural product of fermented wheat germ and found to have a wide spectrum of cytotoxicity against various tumor cell lines under the synergistic activation of L-ascorbic acid (AH2)2,3. Compared with DMQ, DMQ…     

Bioinformatics Assisted Gene Discovery and Annotation of Human Genome

IntroductionBioinformatics is coming with Human GenomeProject(HGP) . With the explosions of sequence,structural and other information available ,bioinformatics is playing an increasingly large rolein the study of fundamental biomedical problems.At present and in the near future,it is the mainchallenge for bioinformatists to make gene dicoveryand annotation of human genome sequences whenthe vast amount of data is produced by the highthroughput genome sequencing in a large scale andautomated m…     

Surface Activities of Calix[4] resorcinarenes Bearing Four Hydrophobic Chains and Its Sol ubilization for Organic Compounds

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｃｌｕｓｉｏｎｃｏｍｐｏｕｎｄｓｈａｖｅｂｅｅｎｎｏｔｅｄｉｎｒｅｃｅｎｔｙｅａｒｓａｎｄｒｅｓｏｒｃｉｎｏｌ ｔｙｐｅｃａｌｉｘ [4 ]ａｒｅｎｅｈａｓｂｅｅｎｓｔｕｄｉｅｄｆｏｒｔｈｅｉｒｉｎｃｌｕｓｉｏｎａｂｉｌｉｔｉｅｓｂｙＳｃｈｅｉｄｅｒａｎｄＢｕｇｌｅｒｅｔａｌ[1— 3] .Ｔｈｅｐｏｌｙｏｌｍｏｉｅｔｉｅｓｉｎｃａｌｉｘ[4 ]ｒｅ ｓｏｒｃｉｎａｒｅｎｅｆｏｒｍｒｉｇｉｄｈｙｄｒｏｇｅｎ ｂｏｎｄｉｎｇｎｅｔｗｏｒｋｓ[4 ] ,ａｎｄｃａｌｉｘ [4 ]ｒｅｓｏｒｃｉｎａｒｅ…     

A New Organo-templated Layered Zincophosphate Synthesized from a Solvothermal System Containing Racemic1,2-Diaminopropane

IntroductionSince Wilson and co- workers successfullysynthesized three- dimensional microporousaluminophosphates (Al PO4 - n ) [1] in the 1 980 s,much attention has been focused on the explorationof1 - D chain,2 - D layer and3 - D open- frameworkmetal phosphates from aqueous or non- aqueoussystems.The number of metals incorporated intothe frameworks of these materials is continuouslyincreasing and the metals include Be[2 ] ,Ga[3] ,In[4 ] ,Sn[5] ,Sb[6 ] ,and the transition metals Zn[7] ,Ni…     

Antioxidative Effect of Schiff Bases with o-Hydroxybenzylidene Groupon Free Radical Induced Hemolysis of Human Red Blood Cell

IntroductionThe recent development of free radical biologyand medicine has provided a great deal of clinicaland experimental evidence indicating that the freeradical induced peroxidation of membrane lipids isassociated with a variety of chronic healthproblems,such as cancer,atherosclerosis andageing[1,2 ] . Both natural and synthetic antioxidantshave been used to trap peroxyl radicals and/orinitiating radicals to protect the membrane lipidsagainst free radical chain reactions,and hence mayhave…