Abstract
Studies on the Boulton-Katritzky rearrangement of 3-(2-aminoaryl)-1,2,4-oxadiazoles
have led to the identification of additional electronic factors
that govern the rearrangement as well as a competitive thermal rearrangement
pathway for select substrates. To circumvent the limitations of
the conventional thermal conversion sequence an improved protocol
that employs microwave irradiation has been devised that allows
access to rearrangement products in good to excellent isolated yields.
Furthermore, we have developed a two-component, one-pot sequence
using a microwave-assisted oxadiazole condensation/Boulton-Katritzky
rearrangement to deliver 3-(acylamino)-1H -indazoles
from simple esters and 2-amino-N -hydroxy-benzamidine
Key words
Boulton-Katritzky rearrangement - indazole - microwave-assisted - oxadiazole condensation - substituent
effects
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[4
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