Biomedical Engineering Reference
In-Depth Information
SCHEME 6.16
Ugi 4CR to achieve macrocycles through bifunctional peptidomimetic build-
ing blocks.
Several subtypes of such reactions conceived the diversity-oriented character of this
synthetic approach by varying both the type and the number of MCRs and compo-
nents involved, and changing the directionality of the amide bonds formed as well. In
this paper, the authors reported the Ugi 4CR to form the macrocycle desired in either
a uni- or a bidirectional way, which was referred to as having the resulting dipeptide
moieties running in the same (parallel) or the opposite (counter) direction (the N- to
C-terminal direction), respectively (Figure 6.3).
The generation of peptide-like macrocycles via multiple multicomponent macro-
cyclizations using bifunctional building blocks allowed for achieving macrocycles
with diverse properties, such as ring size, flexibility, rigidity, core size, shape, or
polarity distribution. The same approach was applied successively to hybrid macro-
cycles containing steroid-peptoid moieties [38]. This paper proposed the generation
FIGURE 6.3
Uni- and bidirectional approaches to macrocyclization through Ugi 4CR.
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