A convenient one-pot synthesis of N -substituted amidoximes and their application toward 1,2,4-oxadiazol-5-ones

The first direct one-pot approach for the synthesis of N-substituted amidoximes from secondary amides or the intermediate amides has been developed. Through the Ph3P–I2-mediated dehydrative condensation, a variety of N-aryl and N-alkyl amidoximes (R1(C <svg xmlns="http://www.w3.org/2000/svg" version="1.0" width="13.200000pt" height="16.000000pt" viewBox="0 0 13.200000 16.000000" preserveAspectRatio="xMidYMid meet"><metadata> Created by potrace 1.16, written by Peter Selinger 2001-2019 </metadata><g transform="translate(1.000000,15.000000) scale(0.017500,-0.017500)" fill="currentColor" stroke="none"><path d="M0 440 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z M0 280 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z"/></g></svg> NOH)NHR2, where R1 or R2 = aryl, alkyl, or benzyl) were readily afforded under mild conditions and short reaction times. The synthetic application of the obtained amidoximes has also been demonstrated through the formation of 1,2,4-oxadiazolones via base-mediated carbonylative cyclization with 1,1′-carbonyldiimidazole.