Catalyzed ring transformation of cyclic N-aryl-azadiperoxides with participation of α,ω-dithiols

Co(OAc)2-catalyzed ring transformation reaction of 10-aryl-7,8,12,13-tetraoxa-10-azaspiro[5.7]tridecanes with α,ω-dithiols giving 3-aryl-1,5,3-dithiazacyclanes was studied.

One-pot cis-selective route to sugar-fused thiazines via a masking–unmasking strategy in basic ionic liquid

A novel sequential Knoevenagel condensation, thia-Michael, and amino/mercaptoacetylative ring transformation reaction cascade for cis-selective synthesis of sugar-fused 1,3-thiazine is reported. The expeditious one-pot multicomponent annulation was performed using masked amino acid viz. 2-phenyl-1,3-oxazol-5-one or masked mercaptoacid viz. 2-methyl-2-phenyl-1,3-oxathiolan-5-one, d-xylose/d-glucose, and N-aryldithiocarbamic acid in ionic liquid [bmim]OH. The acetophenone obtained as a by-product and [bmim]OH itself could be easily recycled for further use without loss of efficiency. The envisaged method is operationally simple, high yielding, and excellent diastereoselective in favor of the cis-isomer of fused thiazines.

New Catalytic Method for the Synthesis of 2,7-Dicycloalkyl-hexaazaperhydropyrenes

An efficient method for the synthesis of 2,7-dicycloalkyl-2,3a,5a,7,8a,10a-hexaazaperhydropyrenes by the NiCl2·6H2O-catalyzed ring transformation reaction of 1,3,5-tricycloalkyl-1,3,5-triazines with 1,4,5,8-tetraazadecalin has been successfully developed.

Synthesis and Modification of Substituted 2-Azaanthraquinones

The cycloaddition-ring transformation reaction sequence of pyrido[1,2-a]pyrazines with substituted naphthoquinones furnished a series of new highly substituted azaanthraquinones. Whereas monosubstituted naphthoquinones were normally leading to two regioisomeric products, in some cases a preference for only one regioisomer was observed. The amino derivative 3b which was isolated as the main product proved to be suitable for further modifications at the primary amino group. The derivatives obtained possess groups capable of connecting the molecule with other substructures for applications as functional dyes. The newly synthesized azaquinones show strong and very broad absorptions between 400 and 600 nm in their UV/Vis spectra