<P>Heterocyclic sulfonyl chlorides, such as pyrimidine-2-sulfonyl
chloride and benzimidazole-2-sulfonyl chloride are unstable at room
temperature.1-3 Pyrimidine-2-sulfonyl chloride rapidly
decomposes to 2-chloropyrimidine2 and, in the case of benzimidazole-2-sulfonyl
chloride, byproducts are 2-chlorobenzimidazole and 2-hydroxybenzimidazole.3 Therefore,
for entries 10 and 11 in Table 2 and entries 9 and 10 in Table 3,
the yields quoted pertain to these byproducts and not to the corresponding
sulfonyl chlorides.
</P><P>
References:
(1)
Richard, O.; Roblin, O.; James, W. J. Am. Chem. Soc. 1950, 72, 4890.(2)
Bornholdt, J.; Fjære, K. W.; Felding , J.; Kristensen,
J. L. Tetrahedron 2009, 65, 9280.(3) S. Wright, W.; Hallstrom, K.
N. J. Org. Chem. 2006, 71, 1080.</P>
