الخلاصة

The aim of this work , synthesis of various hetero cycles (three, four, five, six, seven, and eight ) –membered ring , containing one or more of hetero atoms as (N, S, O). This work involved five part , first part included synthesis of compounds (1-5) derived from cysteine when react with hydrazine , followed by electrophilic reactions to yield (aziridine ,diaziridine ,diazetidine, isoindole, diazine ) derivative . In second part ,the compound (6-14) was synthesized from reaction of phenylene diamine with carbondisulfide or glycine with phthalic anhydride to yield (thiazetidine,thiazepine, thiazolidine, diazirine,diazocin, benzimidazole, isoindole) derivatives .Third part, involved synthesis of triazole derivatives ( 17 ) from azotation of 1,3,4-thiadiazole to give (azo-imine ) compound (16) , followed by cyclization reaction. Four part involved synthesis of several hetero cycles from reaction of 1, 3,4- thiadiazole with sugars (xylose, arabinose, ribose), then reacted with (o-thiol benzoic, glycine, salicylic acid ) to produce the compounds (18-23) . Five parts involved study of biological activity of some compounds. The structure of these compounds were characterized by (H.NMR ,FT.IR ,C.H.N) techniques and their melting