Synthesis of various carbonyl groups using nitrosating reagents

Abstract

Nitrosation of organic carbon, nitrogen, and sulfur compounds with alkyl nitrite (RONO) and dinitrogen tetroxide ($N_2O_4$) were studied. When various hydrazines such as aryl-, carbonyl-, and sulfonyl hydrazines were reacted with dinitrogen tetroxide, the corresponding azides were obtained in excellent yields under mild conditions at low temperature ($-20\,^\circ\!C \sim 40\,^\circ\!C$) in acetonitrile. The yields of the azides are markedly high when the reaction temperatures are controlled at lower than -20$^\circ$C. While, p-nitrophenyl-, and phenyl azides appear to rearrange to the heterocycles due to their instability at high temperature. Treatment of various oximes and hydrazones which are usually employed as ketone or aldehyde functional group equivalents in organic synthesis with dinitrogen tetroxide at low temperature ($-30\,^\circ\!C \sim -40\,^\circ\!C$) in aprotic solvents such as tetrahydrofuran or acetonitrile gave the corresponding ketones respectively in excellent yields. Various $\alpha$-oximino compounds were prepared by reacting carbonyl compounds containing active methylene groups with methyl nitrite, and, it was found that these $\alpha$-oximino compounds were reacted with dinitrogen tetroxide to give the corresponding 1,2-diketones and 1,2,3-triketones in good yields under mild conditions at low temperature ($-20\,^\circ\!C \sim -10\,^\circ\!C$) in aprotic solvents. Of all the derivatives of the carboxyl group, an amide bond is the hardest to break hydrolytically. Some primary carboxyl amides such as benzamide were reacted with excess amount of dinitrogen tetroxide in acetonitrile at low reaction temperature (ca.-20$^\circ$C), and found to convert to the corresponding carboxylic acids in moderate yields. While some sulfonamides such as toluenesulfonamide were found to convert to the corresponding sulfonic acids quantitatively in shorter reaction time (ca.30 min.) than carboxyl amides(ca.2hrs). It was also found that primary carboxyl amides ...