Chemistry Reference
In-Depth Information
3.12 1 ! (1 þ 1 þ 1) BRANCHED MONOMERS
Methyl isocitrate (MeO
2
CCHOHCH
2
CO
2
Me) was alkylated with CH
2
¼
CHCH
2
Br, then MOM-protection to give MeO
2
CCHO(MOM)CH(CH
2
CH
CH
2
)-
CO
2
Me, subsequent ozonation, oxidation, esterification, and deprotection gave
MeO
2
CCOHCH(CO
2
Me)(CH
2
CO
2
R); lastly O-esterification and selective terminal
deesterification generated MeO
2
CCO(OR)CH(CO
2
Me)(CH
2
CO
2
H) [184].
¼
The treatment of 3
,7
,12
-triacetyloxy-5
b
-cholanic acid with 1-naphthylmethyl-
a
a
a
3
,7
,12
-trihydroxy-5
b
-cholan-24-ate generated the tetramer via its use as a 1
!
3
a
a
a
branched monomer [185,186].
3.13 CONCLUSION
3 branching monomers are taken from the literature and
some have been incorporated into macromolecular frameworks; others have not but
possess the attributes to permit their consideration. Almost all dendritic assemblies
are based on a single, iterative procedure, thus the introduction of synthetic diversity
is still lacking in most cases. It would appear that, in general, the insertion of
1
The above examples of 1
!
1) branching monomers possessing a useful attachment point would add a
tailored internal component for molecular inclusion/attachment. Literature possesses
!
(2
þ
