Decomposition N-nitrosohydroxyalkylureas and N-nitrosooxazolidones in aqueous buffer

Area of Science:

• Organic Chemistry
• Chemical Kinetics
• Analytical Chemistry

Background:

• N-nitroso compounds are a class of organic compounds with potential health implications.
• Understanding their decomposition pathways is crucial for risk assessment and environmental monitoring.
• Previous studies have explored the stability of various N-nitroso compounds under different conditions.

Purpose of the Study:

• To investigate the decomposition mechanisms of N-nitroso-2-hydroxyethylurea, N-nitrosooxazolidone, N-nitroso-2-hydroxypropylurea, and N-nitroso-5-methyloxazolidone.
• To identify and quantify the aldehyde and ketone products formed during decomposition.
• To compare the decomposition yields and product profiles of these related N-nitroso compounds.

Main Methods:

• Decomposition studies were conducted in pH 7.4 phosphate buffer.
• Aldehydes and ketones were derivatized using dinitrophenylhydrazine.
• High-performance liquid chromatography (HPLC) was used for the analysis of the dinitrophenylhydrazine derivatives.

Main Results:

• N-nitroso-2-hydroxyethylurea yielded 25% acetaldehyde dinitrophenylhydrazone.
• N-nitrosooxazolidone produced only 2% of the corresponding hydrazone, with 1,3-dioxolane-2-one (ethylene carbonate) as a major product.
• Ethylene glycol was a significant product from both N-nitroso-2-hydroxyethylurea and N-nitrosooxazolidone.
• The other two N-nitroso compounds studied yielded similar products but in substantially lower quantities.

Conclusions:

• The decomposition pathways of the studied N-nitroso compounds vary, leading to different product distributions.
• N-nitroso-2-hydroxyethylurea is a more significant precursor to acetaldehyde compared to N-nitrosooxazolidone.
• Ethylene glycol is a common degradation product, indicating shared decomposition mechanisms.
• The yields of decomposition products are generally low for N-nitroso-2-hydroxypropylurea and N-nitroso-5-methyloxazolidone.