Nitrosyl cyanide, a putative metabolic oxidation product of the alcohol-deterrent agent cyanamide

Abstract When incubated with catalase/glucose-glucose oxidase, 13 C-labeled cyanamide gave rise not only to 13 C-labeled cyanide, but also to 13 C-labeled CO 2 . Moreover, a time-dependent formation of nitrite was observed when cyanamide was oxidized in this system. These results suggested that the initial product of cyanamide oxidation, viz. N -hydroxycyanamide, was being further oxidized by catalase/H 2 O 2 to nitrosyl cyanide (ONCN). Theoretically, nitrosyl cyanide can hydrolyze to the four end-products detected in the oxidative metabolism of cyanamide in vitro , viz. nitroxyl, cyanide, nitrite, and CO 2 . Accordingly, both unlabeled and 13 C-labeled nitrosyl cyanide were synthesized by the low temperature (−40 to −50 °) nitrosylation of K-(18-crown-6) cyanide with nitrosyl tetrafluoroborate. The product, a faint blue liquid at this temperature, was transferred as a gas to phosphate-buffered solution, pH 7.4, where it was solvolyzed. Analysis of the headspace by gas chromatography showed the presence of N 2 O, the dimerization/dehydration product of nitroxyl, while cyanide was detected in the aqueous solution, as measured colorimetrically. [ 13 C]CO 2 was analyzed by GC/MS. An oxidative biotransformation pathway for cyanamide that accounts for all the products detected and involving both N -hydroxycyanamide and nitrosyl cyanide as tandem intermediates is proposed.