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Letters in Organic Chemistry
ISSN: 1570-1786
Letters in Organic Chemistry
Volume 4, Number 2, March 2007
Chiral Pyrrolidine-Based Salen Ligands for the Enantioselective
Alkylation of Aromatic Aldehydes Pp. 80-85
M. Elisa da Silva Serra, Dina Murtinho, Albertino Goth
and A.M. d’A. Rocha Gonsalves
[Abstract]
New Synthesis of 3-Aryl Isoquinolines by Pd-Catalyzed
Suzuki Cross-Coupling Pp. 86-91
Marco Franceschin, Stefano Frasca, Antonello Alvino and
Armandodoriano Bianco
[Abstract]
An Efficient Synthesis of Simple β,β'-Cyclobisalkylated
Melatoninergic Phenylalkylamides Pp. 92-95
Andrew Tsotinis, Margarita Vlachou, Demetris P. Papahatjis,
Spyros P. Nikas and David Sugden
[Abstract]
Scaffold Assembly of Collagen-Like Triple Helices
at the C-Terminus Pp. 96-101
Weibo Cai, Joseph P. Taulane, Nohemy A. Sorto, Asmik Oganesyan,
Carlos G. Gutierrez and Murray Goodman
[Abstract]
Synthesis of 1,2,3,4-Tetrahydroisoquinoline-1-Carboxylic
Acid Derivatives Via Ugi Reactions Pp. 102-108
Ildikó Schuster, Anita Sztojkov-Ivanov, László
Lázár and Ferenc Fülöp
[Abstract]
Base Catalyzed Double Addition of Secondary Phosphine
Chalcogenides to Benzoylacetylene Pp. 109-111
Tatyana E. Glotova, Marina Yu Dvorko, Svetlana N. Arbuzova,
Igor A. Ushakov, Svetlana I. Verkhoturova, Nina K. Gusarova
and Boris A. Trofimov
[Abstract]
Triindolylmethane: Selective Receptor for Chloride
Anion Pp. 112-119
Wataru Oi, Makoto Nishiki and Kazuaki Ito
[Abstract]
A Facile Regioselective Synthesis of Tetracyclic Sulphur
Heterocycles by Tandem Thio-Claisen Rearrangement
Pp. 120-122
Krishna C. Majumdar and Nilasish Pal
[Abstract]
Supporting
Data Pp. i
First Efficient Synthesis of Enantiopure Homoketopinic
Acid Pp. 123-125
Antonio García Martínez, Santiago de la
Moya Cerero, Enrique Teso Vilar, Amelia García Fraile,
Cristina Díaz Morillo and Tomás de las Casas
Engel
[Abstract]
A Simple and Efficient Synthesis of (S)-
and (R)-1-(3-Methoxyphenyl) Ethylamine Pp.
126-128
Meng Hu, Fu-Li Zhang and Mei-Hua Xie
[Abstract]
Three-Component Synthesis of Dihydro-4-pyridones Catalyzed
by Silica Sulfuric Acid Pp. 129-133
Wei-Yi Chen and Xin-Sheng Li
[Abstract]
Synthesis of Pyrimidine-Annulated Heterocycles: Facile
Sulfoxide Rearrangement of 1, 3-Dimethyl-5-(Aryloxybut-2-Ynylthio)
Pyrimidine-2, 4-Dione Pp. 134-136
Krishna C. Majumdar, Pradip K. Maji and Amarta K. Pal
[Abstract]
Supporting
Data Pp. i-ii
New 3-[(4-Hydroxy-6-Methly-2(1H)-Pyridinones)-3-yl]-4
Substituted -(1H)-1,2,4-Triazole-5-Thiones: Efficient Synthesis,
X Ray Crystallographic Analysis, and Antitumor Activity
Pp. 137-141
Jian-Guo Yang and Fu-You Pan
[Abstract]
Synthesis of Alkyl β-D-Glcp-(1→3)-[β-D-Glcp-(1→6)]-β-D-Glcp-
(1→6)-β-D-Glucopyranosides
with Anti-Tumor Activity Pp. 142-145
Linsen Heng, Qianfei Zhao, Xiangdong Mei, Haibin Lv, Xiaohui
Jiang and Jun Ning
[Abstract]
Suzuki-Miyaura Cross-Coupling Reaction in the Functionalization
of the C Ring of Morphinans Pp. 146-150
Attila Sipos and Sándor Berényi
[Abstract]
Abstracts
[Back to top]
Chiral Pyrrolidine-Based Salen Ligands for the Enantioselective
Alkylation of Aromatic Aldehydes
M. Elisa da Silva Serra, Dina Murtinho, Albertino Goth
and A.M. d’A. Rocha Gonsalves
A new type of Salen ligands derived from (2R, 3R)-N-benzyl-2,3-diaminopyrrolidine
and aromatic hydroxyaldehydes was synthesized and tested in
the enantioselective alkylation of aromatic aldehydes with
diethylzinc, moderate selectivity being observed. This study
represents the application of a new type of Zn-Salen ligands
and opens the way to exploring these promising new structures
in other enantioselective and biological processes.
[Back to top]
New Synthesis of 3-Aryl Isoquinolines by Pd-Catalyzed
Suzuki Cross-Coupling
Marco Franceschin, Stefano Frasca, Antonello Alvino and
Armandodoriano Bianco
A new synthetic approach to 3-aryl isoquinolines, based on
the Pd-catalyzed Suzuki cross-coupling reaction, is reported.
The described procedure represents an efficient method to
prepare 3-aryl isoquinolines by reaction of a preformed 3-chloro
isoquinoline with a phenylboronic acid, especially when the
nitrogen atom is positively charged.
[Back to top]
An Efficient Synthesis of Simple β,β'-Cyclobisalkylated
Melatoninergic Phenylalkylamides
Andrew Tsotinis, Margarita Vlachou, Demetris P. Papahatjis,
Spyros P. Nikas and David Sugden
Treatment of the commercially available 3-methoxyphenylacetonitrile
(6) with sodium bis (trimethylsilyl)amide
and subsequent cyclobisalkylation with α,ω-dibromo
or dichloroalkanes in THF at 0 oC produces adducts
7a-d, which serve as precursors to the new
conformationally constrained phenylalkylamides 5a-h.
Compounds 5a-f are melatonin receptor agonists
in the Xenopus laevis melanophore assay and their
potency depends on both the size of the R group and the size
and shape of the β-substituent.
The fact that the cyclohexano-substituted analogs 5g
and 5h are, regardless of the size of the
R group, melatonin receptor antagonists, implies that the
nature of the β-substituent
constitutes a functional probe in the receptor’s dynamic
agonist-antagonist conformational equilibrium.
[Back to top]
Scaffold Assembly of Collagen-Like Triple Helices
at the C-Terminus
Weibo Cai, Joseph P. Taulane, Nohemy A. Sorto, Asmik Oganesyan,
Carlos G. Gutierrez and Murray Goodman
Here, we report the C-terminal scaffold assembly of triple
helical collagen mimetics using a triserine lactone (TSL)
scaffold. It was found that the TSL scaffold can promote the
triple helix formation and enhance the thermal stability of
the resulting collagen-like structures.
[Back to top]
Synthesis of 1,2,3,4-Tetrahydroisoquinoline-1-Carboxylic
Acid Derivatives Via Ugi Reactions
Ildikó Schuster, Anita Sztojkov-Ivanov, László
Lázár and Ferenc Fülöp
The three-component Ugi reactions of 3,4-dihydroisoquinolines,
isocyanides and acids furnished 2-acyl-N-substituted-1,2,3,4-tetrahydroisoquinoline-1-carboxamides
in moderate to good yields. Chiral, non-racemic acids induced
only poor diastereoselectivities in the condensations. Hydrolysis
of the Ugi carboxamides gave the corresponding 1,2,3,4-tetrahydroisoquinoline-1-carboxylic
acids, which due to their ready ability to undergo racemization,
were obtained as racemic mixtures or with low enantiomeric
excesses.
[Back to top]
Base Catalyzed Double Addition of Secondary Phosphine
Chalcogenides to Benzoylacetylene
Tatyana E. Glotova, Marina Yu Dvorko, Svetlana N. Arbuzova,
Igor A. Ushakov, Svetlana I. Verkhoturova, Nina K. Gusarova
and Boris A. Trofimov
Secondary phosphine chalcogenides add to benzoylacetylene
in KOH-THF suspension (the addition proceeds solely to the
triple bond) to form depending on the PH-addend nature and
reaction conditions either α,β-
or β,β-diadducts,
regardless of reactant ratio.
[Back to top]
Triindolylmethane: Selective Receptor for Chloride
Anion
Wataru Oi, Makoto Nishiki and Kazuaki Ito
Anion binding properties of triindolylmethane was investigated
by 1H NMR spectroscopy in
CDCl3. Triindolylmethane selectively binds chloride
anion over other anions tested. This selectivity will be attributed
to the proper size of the binding pocket for chloride anion
and the formation of the multiple hydrogen bonds between three
indole NHs and chloride anion.
[Back to top]
A Facile Regioselective Synthesis of Tetracyclic Sulphur
Heterocycles by Tandem Thio-Claisen Rearrangement
Krishna C. Majumdar and Nilasish Pal
Thio-Claisen rearrangement of symmetrically substituted
1,4-but-2-ynes (3a,b and 4)
exhibit tandem cyclization and afforded compounds 5a,b
and 6 in good yields. These sulphides
3a,b and 4 were in turn
prepared from commercially available thiophene. The key step
in this transformation is tandem [3,3] sigmatropic rearrangement.
[Back to top]
First Efficient Synthesis of Enantiopure Homoketopinic
Acid
Antonio García Martínez, Santiago de la
Moya Cerero, Enrique Teso Vilar, Amelia García Fraile,
Cristina Díaz Morillo and Tomás de las Casas
Engel
The first efficient synthesis of enantiopure homoketopinic
acid, an interesting camphor derivative is firstly reported.
The synthetic procedure uses 10-(triflyloxy)camphor as key
electrophilic intermediate. The ability of 10-(triflyloxy)camphor
to react selectively with a charged C-nucleophile
(cyanide anion) without undergoing Grob fragmentation of the
norbornane framework is also demonstrated.
[Back to top]
A Simple and Efficient Synthesis of (S)-
and (R)-1-(3-Methoxyphenyl) Ethylamine
Meng Hu, Fu-Li Zhang and Mei-Hua Xie
A novel one-pot asymmetric reductive amination of 3-methoxyacetophenone
with (S)- or (R)-α-methylbenzylamine
using the combination of Ti(OiPr)4/Raney-Ni/H2
has been reported. This procedure provides excellent yield
and diastereomeric excess. After cleaving the chiral auxiliary,
(S)- or (R)-1-(3-methoxyphenyl)ethylamine
was obtained in high yield.
[Back to top]
Three-Component Synthesis of Dihydro-4-pyridones Catalyzed
by Silica Sulfuric Acid
Wei-Yi Chen and Xin-Sheng Li
Three-component aza-Diels-Alder reactions of Danishefsky’s
diene with aldehydes and amines took place smoothly to afford
dihydro-4-pyridones with high yields in the presence of a
catalytic amount of silica sulfuric acid (SSA). This new protocol
consistently has the advantages of operational simplicity,
economic consideration, and high yield.
[Back to top]
Synthesis of Pyrimidine-Annulated Heterocycles:
Facile Sulfoxide Rearrangement of 1, 3-Dimethyl-5-(Aryloxybut-2-Ynylthio)
Pyrimidine-2, 4-Dione
Krishna C. Majumdar, Pradip K. Maji and Amarta K. Pal
A number of thieno [3,2-b] pyrimidines are regioselectively
synthesized in good yields from 5-(4-aryloxybut-2-ynylthio)
via sulfoxide rearrangement/tandem cyclization protocol
by the treatment of the sulfides with one equivalent of m-CPBA
in chloroform at 0-5oC with stirring the reaction
mixture at room temperature for 2 h.
[Back to top]
New 3-[(4-Hydroxy-6-Methly-2(1H)-Pyridinones)-3-yl]-4
Substituted -(1H)-1,2,4-Triazole-5-Thiones: Efficient Synthesis,
X Ray Crystallographic Analysis, and Antitumor Activity
Jian-Guo Yang and Fu-You Pan
Fifteen new 3-[(4-hydroxy-6-methly-2(1H)-pyridinones)-3-yl]-4-substituted-
(1H)-1,2,4-triazole-5-thione compounds were synthesized from
methyl 4-hydroxy-6- methyl-2-oxo-1,2-dihydropyridine-3-carboxylate
in good overall yields by four step reactions. Molecular structure
of these compounds was confirmed by IR, NMR, MS, elemental
analysis and X-ray diffraction. Their antitumor activities
were evaluated in vitro by the SRB and MTT methods.
The results show that there are two compounds which are highly
effective against KB cells and one compound which is highly
effective against Bel-7402 cells.
[Back to top]
Synthesis of Alkyl β-D-Glcp-(1→3)-[β-D-Glcp-(1→6)]-β-D-Glcp-
(1→6)-β-D-Glucopyranosides
with Anti-Tumor Activity
Linsen Heng, Qianfei Zhao, Xiangdong Mei, Haibin Lv, Xiaohui
Jiang and Jun Ning
Concise and effective synthesis of alkyl tetrasaccharides
were achieved from the key intermediates alkyl 2,3,4-tri-benzoyl-β-D-glucopyranoside
(5) and 2,3,4,6-tetra-O-benzoyl-β-D
glucopyranosyl-(1→3)-[2,3,4,6-tetra-O-benzoyl-β-D
glucopyranosyl-(1→6)]-2,4-di-O-acetyl-α-D-glucopyranosyl
trichloroacetimidate (6), followed by deacylation.
Bioassay of the inhibition of S180 noumenal tumors
showed that alkyl tetrasaccharides could be employed as potential
agent for cancer treatment.
[Back to top]
Suzuki-Miyaura Cross-Coupling Reaction in the Functionalization
of the C Ring of Morphinans
Attila Sipos and Sándor Berényi
New methods have been developed for the functionalization
of the non-aromatic C ring of morphinans with Suzuki-Miyaura
cross-coupling of sulfonates and bromides.
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