probably via dinitromethylide followed by cyclization and loss of nitrogen.

A convenient and unequivocal synthesis of the title compounds from isoselenocyanates, malononitrile or 2-cyanoacetate, and 1,2-dibromoethane or a-halogenated carboxylic acid derivatives is reported. The proposed reaction mechanism involves in situ cyclization of different halogenated compounds with an intermediate keten-N,Se-acetal, generated by the base promoted nucleophilic addition of the acidic cyanomethylenes to aliphatic and aromatic isoselenocyanates. Chemical and spectroscopic evidence for the structures of the new compounds is presented.

Treatment of ω-halo alkylamines 9 and 10 with aryl and alkyl isoselenocyanates 6a-g in the presence of triethylamine in dichloromethane gave the corresponding 1,3-selenazolidines 11a-g and perhydro-1,3-selenazines 12a-g, respectively, in good to excellent yields. Chemical and spectroscopic evidence for the structures of all new compounds are presented,

No abstract

A variety of triazole-oligomers have been prepared under microwave and conventional conditions from novel alkynes and azides.