Mass spectra was used to confirm the structural assignments of vitalethine and ß-alethine. These spectra also provide some additional evidence for the decomposition of vitalethine to ß-alethine, the polymerization of vitalethine to various trimers, and the reduction and/or fragmentation of ß-alethine and vitaletheine to monomers during the mass spectral determinations. Since evidence for heterogeneity for the authentic preparations of vitalethine and beta-alethine was NOT found in other analytical methods such as NMR and IR, it is suspected that the sample preparation and desorption technique used in obtaining these mass spectra, including exposure of vitalethine to solvents and vacuum, produced many of the polymerization and decomposition products during the actual analysis. These polymerization and decomposition reactions are similar to those observed for other compounds in this series and are, in fact, expected based upon the known chemistry of sulfur compounds. For example, a derivative of the thiol in vitaletheine could never be achieved, probably due to its tendency to cyclize through the central amide of vitaletheine.
A mass ion characteristic of naturally-occuring vitalethine (383) is also apparent in vitalethine's suspected enzyme receptor after it was highly purified (to homogeneity) from hog liver by Larry Poulsen and Dan Ziegler's group at the University of Texas at Austin. There is an interesting lack of the beta-alethine peak (~295) in this spectra, suggesting that the enzyme receptor may dramatically stabilize this chemically dynamic molecule. More studies are needed to ensure that the appearance of this particular mass ion for vitalethine is NOT just an extremely unlikely coincidence.
Some mass spectral evidence for vitaletheine V4, or at least its bromo derivative, may have been provided by others. Unfortunately, their interpretation of their data is not consistent with the evidence obtained on the authentic compounds by a variety of techniques. In order to assert that the authentic exemplary compounds are sulfonates, the mass spectra of the authentic compounds would have to contain characteristic masses associated with the alleged sulfonate structures. No such mass ions for sulfonates have been observed in data on any of the mass spectra studies of the authentic exemplary vitaletheine modulators.
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