Y. W. Lim, R. J. Hewitt, B. A. Burkett
SHORT COMMUNICATION
Conclusions
In summary, we have found an alternative fragmentation
pathway for 1,4,2-oxathiazoles bearing a C5-phenyl substit-
uent and a C5-leaving group in the presence of water. Pre-
liminary investigations of this new pathway suggest that ini-
tial ionisation to a 5-phenyl-1,4,2-oxathiazolium species is
followed by trapping with water to afford 5-hydroxy-5-
phenyl-1,4,2-oxathiazole as an intermediate product. Subse-
quent fragmentation to benzoic acid, elemental sulfur and
nitrile then follows. Further studies of the mechanistic de-
tails of this reaction pathway are currently underway in our
laboratories.
Scheme 4. Interception of 4 by addition of ethanol.
Acknowledgments
This work was supported by the Institute of Chemical and
Engineering Sciences, Singapore (ICES/14-145A01), a research
institute under the Agency for Science, Technology and Research
(A*STAR), Singapore.
In experiments with dry deuterioacetonitrile and ethanol
(entry 9), little change in the product distribution of ITC
vs. nitrile was observed as compared to the experiment con-
ducted in the absence of ethanol (Table 1, entry 8). How-
ever, S-phenyl thiobenzoate was not observed as a reaction
by-product, with only ethyl benzoate being detected.
This is indicative that 6 was indeed formed as an interme-
diate, although it cannot be ruled out that that ethyl benzo-
ate was formed by ethanolysis of S-phenyl thiobenzoate. In
the case of deuterioacetonitrile that was not pre-dried
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Received: May 16, 2015
Published Online: July 2, 2015
4842
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