A second, earlier mechanism continues to appear in the literature.[9] The mechanism was proposed in 1921 by the eminent German organic chemist Heinrich Wieland and his student Georg Scheuing (1895–1949).[10][11] Bisulphite was believed to react with the available aromatic amine functional groups to form N-sulfinic acid groups, Ar-NH-SO2H, followed by reaction with aldehyde to form sulfonamides, Ar-NH-SO2CH(OH)-R. The 1980 NMR data that allowed visualization of intermediates does not support this mechanism or the sulfonamides as the chromogenic product.[4]