Conversion of alkanenitriles to amidines and carboxylic acids mediated by a cobalt(II)-ketoxime system

The conversion of sterically unhindered organonitriles RCN (R=Me, Et, n-Pr, n-Bu) into the corresponding amidines RC(=NH)NH2, isolated as the nitrate salts, and carboxylic acids RCO2H proceeds in the appropriate nitrile as so lvent in the presence of Co(NO3)(2). 6H(2)O or the cobalt(II) complex trans -[Co(MeCN)(2)(H2O)(4)](NO3)(2) and a ketoxime R'C-2=NOH (R'(2)=Me-2 or C5H1 0) but does not proceed at all with either the cobalt compound or the ketox ime taken alone. The amidinium nitrates were characterized by C, H, N eleme ntal analyses, FAB(+)-MS, IR, H-1 and C-13{H-1} NMR spectroscopies and the structures of RC(=NH2)NH2+NO3-(R=Et, n-Pr, n-Bu) were determined by X-ray c rystallography, while the carboxylic acids were identified by GC and H-1 an d C-13{H-1} NMR spectroscopies. The reaction proceeds differently with ster ically hindered organonitriles, e.g. i-PrCN and t-BuCN, and-instead of amid inium salts-ammonium nitrate and the appropriate carboxylic acids were iden tified. The structure of trans-[Co(MeCN)(2)(H2O)(4)](NO3)(2), which is anti cipated to be an intermediate in the reaction of Co(NO3)(2). 6H(2)O, was de termined by X-ray diffractometry.