Beilstein J. Org. Chem.2008,4, No. 51, doi:10.3762/bjoc.4.51
, when amides react with electrophile-activated DMSO, the yields are rather low. We have found new electrophiles, 2,4,6-trichloro[1,3,5]triazine (CC) and 2,4-dichloro-6-methoxy[1,3,5]triazine (DCMT), which activate DMSO in the presence of amides to yield methylenebisamides in good to fair yields. The
amides can be aromatic or aliphatic. The operation is simple and the reagents are inexpensive.
Keywords: amides; condensation; DMSO; methylenebisamides; 2,4,6-trichloro[1,3,5]triazine; Introduction
Sulfoxides are activated by electrophiles to produce reactive sulfonium salts. These electrophiles
salts formed from DMSO and electrophiles.
The reactions of amides with DMSO in presence of electrophiles (sulfur trioxide, acetic anhydride, phosphorus pentoxide) give N,N′-methylenebisamides and N-acylsulfilimines, but rather low yields of N,N′-methylenebisamides (20%) [6]. From our previous research
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Graphical Abstract
Scheme 1:
Synthesis of N,N′-methylenedibenzamide using CC-activated DMSO.