Potentiometric pKa and polarographic behaviour of I ,3-indandione-monoxime-2-phenyl azo and four of its substituted derivatives were investigated in buffer solution of pH -2-12. The results showed that the compounds are in the azo-form, where its reduction wave precedes that of the oxime. A mechanism for the electrodic processes was proposed. Half-wave potentials showed fair correlation with Ha...

In the title compound, C(32)H(28), the central cyclo-octa-tetra-ene ring has a boat conformation, and the mol-ecule is saddle shaped. The seat is defined by the mean plane of the four-atom attachment points (r.m.s. deviation = 0.014 Å) of the two bicyclo-heptenyl substituents. These substituents comprise the pommel and cantle, with each mean plane defined by four atoms proximate to the seat (r....

Some new heterocyclic compounds containing isoxazole, pyrazole and oxadiazole ring systems were prepared from various chalcones. The synthesized compounds have been characterized by elemental analysis and spectral methods. These compounds were screened for their antimicrobial activities.

A novel 2',4'-BNA/LNA analog bridged by guanidine, termed as guanidine bridged nucleic acid (GuNA), was synthesized and incorporated into oligonucleotides. Thermal stabilities and nuclease resistance of GuNA-modified oligonucleotides were investigated and compared with those of 2',4'-BNA/LNA and natural DNA oligonucleotides. GuNA exhibited interestingly high binding affinity towards complementa...

Ethynyl-substituted acyclic anion receptors were synthesized for discrete covalently linked and metal-bridged dimers, which form various anionic complexes including double helical structures as the first examples of Cl(-)-bridged [2+2]-type complexes that are stable in the solution state.

This article deals with our recent studies on the synthesis of BNAs (Bridged Nucleic Acids), novel nucleic acid analogs bearing a preorganized sugar conformation by a bridged structure. Duplex- and triplex-forming abilities of the BNA modified oligonucleotides are also described.

Pyrido- and pyrrolo[2,3-d]oxazoles can be conveniently prepared in high yield from the Ritter reaction of nitriles and in situ generated chiral cyclic N-acyliminium ions. cis-4-Hydroxy-5-acylaminopyrrolidines and cis-5-hydroxy-6-acylaminopiperidines can be readily obtained by acid hydrolysis of these bicyclic heterocyclic compounds, respectively.

Commercially available N-oxide (2-mercaptopyridine-N-oxide) is used as a ligand instead of an oxidizing agent to stabilize the compounds of main group elements in low-valent states. The isolated compounds [(C5H4NOS)2Sn (), (C5H4NOS)SnCl () and (C5H4NOS)GeCl ()] are the first structurally characterized examples of O,S-heterocyclic stannylenes and germylenes with interesting bonding features. Fur...

Chiral N-heterocyclic carbenes were found to be efficient catalysts for the formal [2+2] cycloaddition reaction of alkyl(aryl)ketenes and nitroso compounds to give the corresponding 1,2-oxazetidin-3-ones in moderate to good yields with high enantioselectivities. Reductive ring-opening of the oxazetidinones give the corresponding α-hydroxy acid derivatives in good yields.