1,720,990 research outputs found
Synthesis of 4-Isobutylbenzaldehyde an Important Intermediate for the Fragrance (+)- and (-)-Silvial®
Full text linkThe synthesis of 4-isobutylbenzaldehyde, a valuable precursor for the fragrance Silvial®
(3-(4-isobutylphenyl)-2-methylpropanal), is reported. Three different synthetic approaches are reported starting
either from 4-isobutylbenzoic acid (via benzyl alcohol, or via acyl chloride), or by Suzuki-Miyaura cross-coupling
reaction between 4-bromobenzaldehyde and 2-methylpropylboronic acid
Arylation of β-methallyl alcohol catalyzed by Pd(OAc)2 in combination with P(t-Bu)3: application to fragrance synthesis
No full textPd(OAc)2 in combination with P(t-Bu)3 catalyzes the coupling of b-methallyl alcohol with 1-bromo-3,4-(methylenedioxy)benzene (1a), 1-bromo-4-methoxybenzene (1b), or 1-bromo-4-tert-butylbenzene (1c). The reaction affords the corresponding 2-methyl-3-aryl-propanals, which are valuable floral fragrances. With 1a or 1b high reaction rates are obtained at 130 C using NMP/water mixtures and an inorganic base such as Na2CO3. The chemoselectivity of the reaction is almost complete, so that the process appears practically feasible. In contrast, the coupling of b-methallyl alcohol with 1c proceeds with low reaction rates
Asymmetric catalysis in fragrance chemistry: a new catalytic approach to non racemic Cyclamen-aldehyde
No full textA new catalytic synthesis of Cyclamen-aldehyde (3-(4-isopropylphenyl)-2-methylpropanal) has been
developed. The devised synthetic approach entails as the key step the asymmetric hydrogenation of (E)-3-(4-
isopropylphenyl)-2-methyl acrylic acid which has been carried out with ees of about 60% by using a catalytic
system prepared by combining in situ [Ru(C6H6)Cl2]2 and (S)-MeO-BIPHEP
Asymmetric catalysis in fragrance chemistry: a new synthetic approach to enantiopure Phenoxanol®, Citralis® and Citralis Nitrile®
No full textA new approach to the synthesis of the single stereomers of the fragrances Phenoxanol, Citralis and Citralis Nitrile is
reported. The key step of the synthesis is the asymmetric hydrogenation of (Z)- or (E)-3-methyl-5-phenyl-pent-2-en-1-ol, which leads
to the single enantiomers of Phenoxanol from which both enantiomers of Citralis are obtained by oxidation. Treatment of these compounds
with hydroxylamine finally led to Citralis Nitrile without any loss of enantiopurity. The odour profiles of the single enantiomers
of these fragrances are reported as well
Synthesis of the Chiral Fragrance Methyl Chamomile by Asymmetric Hydrogenation
Full text linkAn alternative synthesis of enantiomerically enriched 2-methylpentanoic butyl ester (Methyl Chamomile)
is proposed. The process entails three different steps: the key one is the asymmetric hydrogenation of
2-methylenpentanoic acid catalysed by a Ru(II) complex and a chiral diphosphine
Synthesis and characterization of the first generation of a new hyper-branched dendrimer
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