Biomedical Engineering Reference
In-Depth Information
(a)
(b)
SCHEME 2.15
Ugi Diels-Alder rearomatization.
eventually eliminates morpholine to give densely substituted pyridine products (
111
,
Scheme 2.15b) [44]. A subsequent report demonstrated that oxazole
106
could be
treated with an acid chloride in the presence of a symmetric dienophile to form hex-
asubstituted benzene products after heating. This one-pot process proceeds via furan
113
, which is generated from the elimination of a nitrile to form bicyclic intermediate
115
[46].