AbstractThe 1‐azirine derivatives ofcis‐9‐octadecene and methyl oleate have been prepared, and some of their reactions have been studied. The preparation of these novel fatty acid derivatives was accomplished in a three‐step synthesis with good overall yields. Addition of the electrophile IN3 to the olefin yielded the β‐iodoazide derivatives of octadecane and stearic acid. Treatment of the latter compounds with base resulted in dehydrohalogenation and gave the vinyl azides. Solution photolysis of the vinyl azides yielded the 1‐azirine derivatives. Reduction of the 1‐azirines with metal hydrides gave the known epimino derivatives of octadecane and octadecanol. Other reducing agents were unsuccessful in preserving the three‐membered ring. Reaction with acids caused the dimerization of the 1‐azirines with formation of tetrasubstituted pyrazines. The 1‐azirines were attacked by acid chlorides and hydrochloric acid to give chlorinated amides as principal products.