Propenylsulfenic acid

The answer to all these questions is found in the demonstration (37) that the monomeric, unstable, lachrymatory compound produced by onions is not 1-propenylsulfenic acid, the presumed precursor of the dimer, but, as suggested a decade earlier (38), thiopropionaldehyde-S-oxide (CH CHoCHSO). The mass spectographic evidence which suggested the sulfenic acid structure (22) for this product is consistent with the latter structure. The nuclear magnetic resonance and infrared spectral evidence are consistent only with it. A hypothesis uniting all the evidence is that the true product of the enzymatic reaction is the sulfenic acid, as... 

Contains allylpropyl bisulfide, S-(l - propen y I leys -teine sulfoxide and 1 -propenylsulfenic acid which is thought to be the lacrimator in onions Virtanen, Sprare, Suom. 

Mercapto-2-propanone, M-60028 (Methylthio)acetaldehyde, in M-80017 (Methylthio)oxirane, M-80173 Propenylsulfenic acid, P-70123... 

---