The organocatalyzed aerobic oxidation of aldehydes to acids was reproduced from the original report. In- and ex-situ analysis of the reaction mixture as the function of time reveals that, unlike the claim in the publication, the aerobic oxidation of aromatic and aliphatic aldehydes leads predominantly to the formation of peracids. The latter are transformed into the corresponding carboxylic acids during the workup procedure. The buildup of peracids in solution poses safety problems that should not be overlooked. This finding has also an influence on the way new catalysts are investigated to improve this reaction as well as on aerobic aldehyde-mediated co-oxidation.

New substituted aroylhydrazones (4a-f) were synthesized from the acid hydrazide (3) and the corresponding aldehyde or aldose. 5-Amino-4-cyano-1H-pyrazole derivatives (6a-f) were prepared by the reaction of the aroylhydrazones (4a-f) with malononitrile. The synthesized compounds were tested for antimicrobial activity against various bacteria and fungi and showed moderate to high inhibition activities. Compounds incorporating a sugar moiety as well as a pyrazolyl ring in their structure displayed the highest antimicrobial activity.