Abstract5‐Pentadecyl‐1,3,4‐oxadiazol‐2‐amine (2) was employed as key intermediate for the synthesis of some new functionalized five and six membered heterocyclic derivatives. The synthesized compounds were reacted with propylene oxide to obtain surface active agents having good surface activity, high solubility in water and good biodegradability. Moreover, the functionalized surfactants showed good antimicrobial activity against gram negative and gram positive organisms. The new compounds are easily synthesized, economical and environmentally friendly and are expected to constitute an important class of organic compounds for medicinal purposes in the future.

Reaction of 5-pentadecyl-1,3,4-thiadiazol-2-amine 2 with ethyl cyanoacetate gave 2-cyano-N-(5-pentadecyl-1,3,4-thiadiazol-2-yl)acetamide 3 which was used to synthesize different heterocyclic derivatives comprising coumarin, pyrazole, thiazole, pyridine, pyrimidine, and thiophene rings. Propoxylation of these compounds by using 5 moles of propylene oxide to produce nonionic surface active agents. Antimicrobial and the surface activities were evaluated.