The preparation and properties of some nitrosamino acids

Abstract

The N-nitroso derivatives of the amino acids sarcosine, azetidine-2-carboxylic acid, proline, hydroxyproline and pipecolic acid have been prepared and characterized. All five compounds are formed in high yield under conditions approximating those in the mammalian stomach. The nitrosamino acids can be decarboxylated in low yield in the presence of dilute alkali, the product in each case being a nitrosamine. The possible relevance of these findings to the occurrence of human cancer is discussed. The variation of NMR spectral properties with time has shown that four of these nitrosamino acids preferentially crystallize in a conformation in which the C atom bearing the carboxyl group is syn to the nitroso O atom, while nitrosoazetidinecarboxylic acid assumes the anti conformation in the crystal. The carboxyl group of nitrosopipecolic acid strongly prefers the axial orientation. © 1970.