4th EucheMs chemistry congress

Poster Session 1
s1013
chem. Listy 106, s587–s1425 (2012)
Poster session 1 - organic chemistry
P - 0 3 0 3
SyntheSiS of new C-PrenyLAted And
o-PrenyLAted CoMPoundS: MoLeCuLeS with
PotentiAL BioLoGiCAL ACtivity
M. A. dettori 1 , d. fABBri 1 , G. deLoGu 1
1 CNR, Institute of Biomolecular Chemistry, Sassari, Italy
Email: a.dettori@icb.cnr.it
Magnolol and honokiol, are significant bioactive
constituents isolated from the bark of Magnolia officinalis which
posses potent anti-oxidative, anti-inflammatory and anti-cancer
activities [1] . The chemical structure of magnolol is a C -symmetry
2
C-C dimer of 4-allyl-phenol which forms a biphenyl skeleton,
whereas honokiol is its structural isomer (congener). It is known
that the presence of a prenyl or geranyl group in natural
polyphenols can lead to a remarkable increase in bioactivity due
to an increment of lipophilicity through interaction with cellular
membranes.
With the aim to prepare compounds similar to magnolol
and honokiol and some polyphenols, commercially available
4,4'--dihydroxy biphenyl, 2,2'-dihydroxy biphenyl, 5,5'-diallyl-
2,2'-dihydroxy biphenyl, 4-(4-hydroxy-3-methoxyphenyl)-butan-
-2-one (zingerone), 4-hydroxy-3-methoxybenzaldehyde
(vanillin), 1-(4-hydroxy-3-methoxyphenyl)-ethanone (apocynin),
1-(2-hydroxy-4-methoxyphenyl)-ethanone and 3,4-dimethoxy -
benzaldehyde (veratraldehyde) were used as starting materials.
Claisen-Schmidt condensation of aryl aldehyde with the
appropriate ketone in the presence of base [2] , allowed us to
achieve α,β-unsatured ketons and calchones endowed with a free-
OH phenolic group in 60-70% yield. Each phenol was treated with
three different unsaturated alkyl halogens (allyl bromide, geranyl
bromide, 1-bromine-3-methyl butene-2) in acetone, in the
presence of K CO to give the corresponding O-prenylated
2 3
derivatives in 70-80% yield.
In order to achieve C-prenylated phenols, the compounds
were further subjected to Claisen rearrangement under both
thermal condition and microwave irradiation.
We were able to prepare directly C-prenylated biphenol by
Heck reaction of linalool with 3,3' dibromo- 4,4'-dihydroxy-1,1'-
-biphenyl, the latter obtained by bromination of 4,4'-dihydroxy
biphenyl in the presence of Br and AcOH.
2
All synthesized compounds were obtained as air stable
solids and easily purified by flash chromatography.
Acknowledgement: This work has been supported by Sardinia
Autonomous Region (L.R., August 7th 2007, n. 7)
references:
1. Kong Z. L. et al. Bioorganic & Medicinal Chemistry
Letters 2005, 15, 163.
2. Tatsuzaki J. et al. J. Nat. Prod. 2006, 69, 1445.
Keywords: magnolol; prenylated compund; phenol;
4 th EucheMs chemistry congress
P - 0 3 0 4
BifunCtionAL MeSoPorouS SiLiCA
nAnoPArtiCLeS viA CLiCK-CheMiStry
– CooPerAtive CAtALySiS At SurfACe
A. diCKSChAt 1 , f. BehrendS 2 , h. eCKert 2 ,
A. Studer 1
1 Chemisches Institut, Organische Chemie, Münster, Germany
2 Chemisches Institut, Physikalische Chemie, Münster, Germany
Mesoporous materials with size-tunable mesopores have
been widely used in the past few years. Among these
multifunctional catalytic systems have attracted a great deal of
interest. Inorganic-organic hybrid-materials like MCM-41
combine both flexibility and ease in synthesis of the organic
component as well as rigidity and thermal stability of the
inorganic framework.
A precise attachment of organic functionalities onto
mesoporous silica nanoparticles (MSNs) can be achieved either
by post grafting of an organosilicon compound or by the
co-condensation method.
Several examples are known wherein the concept of a dual
activation of nucleophiles and electrophiles by acids and bases
respectively lead to synergistic catalytic enhancements. Herein
we present the synthesis of acid-base bifunctional MSNs via
co-condensation of tetraethoxyorthosilicate (TEOS) and various
triethoxysilanes bearing orthogonal and therefore subsequently
addressable functionalities. Their catalytic performance has been
tested in the Henry-reaction.
Via this approach we were also able to bring on ligands at
surface and immobilize transitionmetals into the mesoporous
particles in order to catalyze cross-coupling reactions.
Keywords: binfuctional catalysis; mesoporous silica
nanoparticles; heterogeneous catalysis; cooperativity;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc