A new method to synthesize $\alpha$ -oximinoketones usint alkyl thionitrate under mild conditons was found. The reaction of ketones with t-butyl thionitrate in THF containing HCl gas at 0 $^\circ$C afforded the corresponding $\alpha$ -oximinoketones in excellent yields. it was found that various thioacetals and thioketals redily reacted with t-butyl thionitrate or t-butyl thionitrate under mild conditions in acetonitrile without aqueous media to afford the corresponding parent carbonyl compound in excellent yields. A number of N-p-tosylslfilimines were converted into the corresponding sulfoxides by the reaction with dinitrogen tetroxide in good yields. During the investigation on the $\alpha$ -disulfoxide, it was found that various thiols reacted smoothly with sulfuryl chloride and potassium nitrate to give the corresponding sulfonyl chlorides in acetonitrile in excellent yields. But, hetero aromatic thiols were readily converted into the corresponding chlorinated compounds by the reaction with sulfuryl chloride and potassium nitrate in high yields. Arenesulfonyl nitrites as a new nitrosating reagent were prepared and confirmed by the low temperature UV and IR spectroscopy. Various primary amino groups were reacted with benzenesulfonyl nitrite to give the corresponding reductive deaminataion products. Various sulfides were oxidized to the corresponding sulfoxide without overoxidation to sulfones by the reaction with benzenesulfonyl nitrite. It was found that various $\beta$ -lactams were prepared from the reaction of $\beta$ -amino acid with 2, 2-dipyrimidyl disulfide and triphenylphsphine in excellent yields.