Nano SnCl۴.SiO۲ as an efficient catalyst for the synthesis of N-nitrosamines based on secondary amines under mild and heterogeneous conditions

چکیده مقاله

Background: Nitrosamines are present in water, soil and air. They can be found contaminating food, feeding stuff, drugs, cosmetics, and pesticides [1]. Nitrosamines are absorbed by skin, air-ways and the alimentary tract. There is evidence that nitrosocompounds may be generated in vivo from nitrites or nitrates and primary, secondary and tertiary amines in organs of people who apparently were not exposed to these compounds [2]. Methods: Nano SnCl4.SiO2 was used as a recoverable acidic solid catalyst for one-pot synthesis of N-nitrosamine derivatives via three component condensation of sodium nitrite (1mmol), secondary amine and wet SiO2. Results: To design a green procedure for the N-nitrosation of secondary amines by in situ generation of nitrosoniume ion (NO+), different types of secondary amines has been converted into corresponding N-nitrosoamines using nano SnCl4.SiO2 and sodium nitrite with good to excellent yields (Scheme 1). Initially, to optimize the reaction conditions, different molar ratio of sodium nitrite and nano SnCl4.SiO2 reacted with dibenzylamine in dichloromethane at room temperature and the best condition was obtained. Under, obtained optimize conditions secondary amines were converted into N-nitrosoamines. Because of mild and heterogeneous conditions of described system, there was no nitration product observed for aromatic rings of amines.