To date, only a few instances of S4-symmetric organic molecules exist. In principle, spirobi-(dinaphthoazepin)ium cations can achieve this highly symmetric point group. Heating racemic 2,2′-bis(bromomethyl)-1,1′binaphthyl with aqueous ammonia afforded mixture rac- and meso-3,3′,5,5′-tetrahydro-4,4′-spirobi[dinaphtho[2,1-c:1′,2′-e]azepin]-4-ium bromide which was separated by fractional crystalli...

A systematic study on the distortion of a naphthalene ring was performed using steric repulsion between peri-substituents at 1- and 8-positions. The introduction bromo groups into methyl 1,8-dimethylnaphthalene enhanced to distort ring. X-ray crystallography revealed that 1,8-bis(bromomethyl)naphthalene had vertical with 11.0° dihedral angle (α) which disturbed coplanarity On other hand, 1,8-bi...

A new total synthesis of the alkaloid variolin B is achieved by a selective and sequential palladium-mediated functionalization of a trihalo-substituted pyrido[30,20:4,5]pyrrolo[1,2-c]pyrimidine. This intermediate is obtained by a new heterocyclization reaction between an appropriate bromomethyl azaindole and N-tosylmethyl dichloroformimide. The methodology may be effective for the synthesis of...

A series of ionophores based on diaza 18-crown-6 units possessing amide and sulfonamide functions were prepared. Their complexing properties were investigated in solvent polymeric membrane electrodes. The influence of the structure of ligands, prepared on the selectivity of complexation, was examined with special respect to lead ions. Substantial changes were observed, when methyl substituent i...

A convenient and efficient method for the constructions of 3-spirooxindole derivatives or 3,3'-disubstituted oxindoles has been developed from one-pot reactions of isatins, hydrazides or aromatic amines, 2-(bromomethyl)acrylic ester and tin powder in the presence of a catalytic amount of Brønsted or Lewis acid. The method avoids the use of toxic stannanes and allows easy operation. It is also p...

Barton esters have been introduced into the side chain of carbohydrates with high yields in only a few steps from easily available glycals. Their radical reactions afford 2-C-methyl and 2-C-bromomethyl hexoses, pentoses and disaccharides in good yields in analytically pure form. Since the Barton esters have been synthesized by an oxidative radical addition and their transformations by reductive...