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Letters in Organic Chemistry
ISSN: 1570-1786
Letters in Organic Chemistry
Volume 5, Number 4, June 2008
Contents
4-Hydroxyphenylglycine-Based Polymer-Bound Amino
Alcohols and in-situ-Generated Oxazaborolidines for
Enantioselective Reductions Pp. 244-248
Manfred Braun, Michael Sigloch and Jens Cremer
[Abstract]
Stereoselectivity in the Reaction of Chiral Phenylglyoxylate
Esters with Furan within Zeolites and Cyclodextrin
Pp. 249-256
Maurizio D’Auria, Lucia Emanuele and Rocco Racioppi
[Abstract]
An Example of Total Synthesis of Flavones
by Heck-Sonogashira-Cassar Reaction Pp. 257-261
Armandodoriano Bianco, Claudia Cavarischia, Marcella Guiso
and Teresa Matini
[Abstract]
Syntheses and Glycosidation Reactions of 6-Thiosialosyl Donors
Pp. 262-264
Hideya Yuasa, Yoshitaka Tanetani, Tatsuo Miyazaki, Masayuki
Izumi and Hironobu Hashimoto
[Abstract]
One-Pot Preparation of Bis-Betti Base Product
Pp. 265-268
Ren-Gen Xiong
[Abstract]
Isomer Distribution of Succinylcyclohexenyl, Acetylcyclohexenyl
and Acetylcyclopentenyl Enamines Pp. 269-275
A. Gilbert Cook and Sarah L. Folk
[Abstract]
Regioselective Synthesis of Coumarin and Quinolone-Annulated
Linearly Fused Heterocycles by the Intramolecular Heck Reaction
of the Biaryl Systems Pp. 276-281
Krishna C. Majumdar, Buddhadeb Chattopadhyay and Amarta
K. Pal
[Abstract]
A Novel Four Component One-Pot Access to 4,6-diaryl-2-Pyridinone
and 4-aryl-5,6,7,8-tetrahydro-2-quinolinones Pp.
282-285
Chao-Guo Yan, Xi-Mei Cai, Qi-Fang Wang and Jing Sun
[Abstract]
The Henry Reaction Efficiently Catalyzed
by a Cd-Proline Complex Pp. 286-289
Junke Wang, Zhi-Jin Lu, Le-Yong Wang, Junfeng Bai and
Yi Pan
[Abstract]
Alumina Sulfuric Acid: An Efficient Heterogeneous
Catalyst for the Synthesis of Amidoalkyl Naphthols
Pp. 290-295
Hamid Reza Shaterian, Asghar Hosseinian, Hossein Yarahmadi
and Majid Ghashang
[Abstract]
An Improved Synthetic Protocol and Plausible Mechanism in
Forming Acetylpyridines from 2,6-Dicarbethoxypyridine
Pp. 296-299
Maliha Asma, Sheriff Adewuyi, Xiaofei Kuang, Amin Badshah
and Wen-Hua Sun
[Abstract]
Efficient Synthesis of Bis(indolyl)methanes Using Nano Ceria
Supported on Vinyl Pyridine Polymer at Ambient Temperature
Pp. 300-303
Gowravaram Sabitha, Nandyala M. Reddy, Muddala N. Prasad,
Jhillu S. Yadav, Kurva S. Sivudu and Donempudi Shailaja
[Abstract]
PolyHIPEs as Novel Media for Conventional Free
Radical Chemistry Pp. 304-307
Shengmiao Zhang, Jianding Chen and Victoria T. Perchyonok
[Abstract]
Chemoselective and Efficient Method for Deprotection of THP
and Silyl Ethers with H2O2/
Mn(III) Schiff-Base Complex Pp. 308-312
Mahmood Tajbakhsh, Rahman Hosseinzadeh, Hamid Golchoubian
and Raheleh Razavian
[Abstract]
Synthesis and Characterization of Two Novel
Stigmasterol-Based Cationic Lipids Pp. 313-315
Jia Qian, Zhiping Le, Fei Yu and Pinghan Jiang
[Abstract]
Efficient One-Step Synthesis of Substituted-pyrazolo[3,4-b]pyridine
from Substituted-3-cyano-2(1H)-pyridone
Pp. 316-318
Yasser S. Abdel-Ghany, Aly A. Hazzaa, Mohamad M. Abdul
Ghani and Zahra A. Kassem
[Abstract]
A Simple and Efficient One-Pot Synthesis of Spirooxindoles
in Water Under Microwave Irradiation Conditions Pp.
319-323
Song-Lei Zhu, Shun-Jun Ji , Kai Zhao and Yong Zhang
[Abstract]
Phenolic Glycosides from Viburnum fordiae Hance and
their Antioxidant Activities Pp. 324-327
Bin Wu, Xintian Zheng, Haibin Qu and Yiyu Cheng
[Abstract]
Abstracts
[Back to top]
4-Hydroxyphenylglycine-Based Polymer-Bound Amino Alcohols
and in-situ-Generated Oxazaborolidines for Enantioselective
Reductions
Manfred Braun, Michael Sigloch and Jens Cremer
The chiral amino alcohol HOC6H4CH(NH2)C(C6H5)2OH
(4) that is derived from (R)-4-hydroxyphenylglycine
has been converted into novel soluble and insoluble polymer-bound
reagents 5. After in-situ conversion
into oxazaborolidines, they serve for enantioselective reductions
of acetophenone to deliver (S)-1-phenylethanol (6)
in up to 83% enantiomeric excess.
[Back to top]
Stereoselectivity in the Reaction of Chiral Phenylglyoxylate
Esters with Furan within Zeolites and Cyclodextrin
Maurizio D’Auria, Lucia Emanuele and Rocco Racioppi
The irradiation of chiral phenylglyoxylate esters in
the presence of furan within NaY, LiY, KY, CsY, and RbY showed
in some cases an increase of stereoselectivity in comparison
with the observed stereoselectivity when the reaction was
performed in solution. The enhanced stereoselectivity can
be explained assuming that the biradical intermediate of the
reaction can have an advantage (it occupies a smaller volume)
to assume the correct conformation able to cyclize when the
reaction is performed within a zeolite. This advantage is
greater for the stereoisomer able to give the observed product
than for the other one. In the case of the phenylglyoxylate
ester obtained from (S)-1-methyl-1-propanol, the
stereoselectivity was higher with NaY than with LiY. In the
case of the phenylglyoxylate ester obtained from (S)-2-methyl-1-butanol,
NaY and LiY gave the same stereoselectivity. The effect of
the cation can be explained considering that, in the case
of the phenylglyoxylate ester obtained from (S)-1-methyl-1-propanol,
the interaction between the LUMO of the alkali ion and the
HSOMO of the biradical intermediates was different for SS
and RS stereoisomers. In the case of the phenylglyoxylate
ester obtained from (S)-2-methyl-1-butanol no difference
was observed in the HSOMO of SS and RS stereoisomers
of the biradical intermediates in agreement with the observed
no effect of the change of alkali ions. When the reaction
was performed within β-cyclodextrin
a reduction of stereoselectivity was observed.
[Back to top]
An Example of Total Synthesis of Flavones by Heck-Sonogashira-
Cassar Reaction
Armandodoriano Bianco, Claudia Cavarischia, Marcella Guiso
and Teresa Matini
The use of aryl vinyl ketones in the Heck reaction for
the synthesis of flavonoids was previously described. Herein
we present our preliminary study on the reactivity of aroyl
alkynes or propargyl alcohols in the Heck-Sonogashira-Cassar
coupling reactions to obtain alkynyl precursors of flavones.
This procedure envisaged a general protocol for the synthesis
of variously substituted flavones.
[Back to top]
Syntheses and Glycosidation Reactions of 6-Thiosialosyl Donors
Hideya Yuasa, Yoshitaka Tanetani, Tatsuo Miyazaki, Masayuki
Izumi and Hironobu Hashimoto
The fluoride and thioglycoside derivatives of 6-thiosialic
acid were synthesized. The thioglycoside was found to react
with glycosyl acceptors in the presence of N-iodosuccinimide
and trifluoromethanesulfonic acid. Alkanols tended to be glycosylated
in good yield with β-selectivity,
while sugar alcohols gave only the β-glycosides
in poor yields.
[Back to top]
One-Pot Preparation of Bis-Betti Base Product
Ren-Gen Xiong
A short and facile synthesis of bis-Betti bases with two
chiral carbon centers was achieved firstly. The structures
were established on the basis of IR, elemental analysis, 1HNMR,
and one of the products was confirmed by a single-crystal
X-ray diffraction analysis.
[Back to top]
Isomer Distribution of Succinylcyclohexenyl, Acetylcyclohexenyl
and Acetylcyclopentenyl Enamines
A. Gilbert Cook and Sarah L. Folk
The isomeric distributions of some cyclohexenyl enamines
substituted by succinyl or acetyl groups at either the 2-
or 6-positions are reported as are the isomeric distributions
of similarly substituted cyclopentenyl enamines. Correlation
between the 13C NMR chemical
shifts in these enamines and isomer distribution is shown.
Density functional molecular modeling is used to demonstrate
resonance and electrostatic effects on isomeric distributions.
[Back to top]
Regioselective Synthesis of Coumarin and Quinolone-Annulated
Linearly Fused Heterocycles by the Intramolecular Heck Reaction
of the Biaryl Systems
Krishna C. Majumdar, Buddhadeb Chattopadhyay and Amarta
K. Pal
A simple convergent regioselective synthesis of hitherto
unreported coumarin- and quinolone-annulated heterocycles
in excellent yields has been achieved by the palladium-catalyzed
intramolecular Heck reaction.
[Back to top]
A Novel Four Component One-Pot Access to 4,6-diaryl-2 Pyridinone
and 4-aryl-5,6,7,8-tetrahydro-2-quinolinones
Chao-Guo Yan, Xi-Mei Cai, Qi-Fang Wang and Jing Sun
An efficient one-pot procedure was developed for the
synthesis of 4,6-diaryl-2-pyridinones and 4-aryl-8-arylidene-5,6,7,8-tetrahydro-2-
quinolinones based on cyclocondensation reactions of N-ethoxycarbonylmethylpyridinium
chloride or N-carbamoylmethyl pyridinium chloride
with aromatic aldehydes and substituted acetophenones or cyclohexanone.
The multi-component reaction is performed by microwave irradiation
with the reaction substances in the system of NH4OAc/HOAc.
[Back to top]
The Henry Reaction Efficiently Catalyzed by a Cd-Proline Complex
Junke Wang, Zhi-Jin Lu, Le-Yong Wang, Junfeng Bai and
Yi Pan
The Henry reaction has been efficiently catalyzed by
a Cd-proline complex in water at ambient temperature to afford
the β-nitroalcohols
in good to excellent yields. Effective recovery and recycling
(up to five runs) of the catalyst are documented.
[Back to top]
Alumina Sulfuric Acid: An Efficient Heterogeneous Catalyst
for the Synthesis of Amidoalkyl Naphthols
Hamid Reza Shaterian, Asghar Hosseinian, Hossein Yarahmadi
and Majid Ghashang
An efficient and expeditious direct protocol for the
preparation of amidoalkyl naphthols employing a multi-component,
one-pot condensation reaction of 2-naphthol, aromatic aldehydes
and acetonitrile or acetamide in the presence of alumina sulfuric
acid as a solid heterogeneous acid catalyst under solvent,
solvent-free and microwave conditions has been described.
[Back to top]
An Improved Synthetic Protocol and Plausible Mechanism in
Forming Acetylpyridines from 2,6-Dicarbethoxypyridine
Maliha Asma, Sheriff Adewuyi, Xiaofei Kuang, Amin Badshah
and Wen-Hua Sun
2-Carbethoxy-6-acetylpyridine and 2,6-diacetylpyridine
were transformed in good yields from the reaction of 2,6-dicarbethoxypyridine
and EtOAc in the presence of sodium along with/without an
equivalent of ethanol to sodium in toluene. The β-keto
esters, the intermediates in the transformation of β-keto
carboxylate into acetyl group, were isolated for understanding
the plausible mechanism.
[Back to top]
Efficient Synthesis of Bis(indolyl)methanes Using Nano Ceria
Supported on Vinyl Pyridine Polymer at Ambient Temperature
Gowravaram Sabitha, Nandyala M. Reddy, Muddala N. Prasad,
Jhillu S. Yadav, Kurva S. Sivudu and Donempudi Shailaja
Nano ceria supported on vinyl pyridine polymer was found
to be an effective and reusable catalyst for the synthesis
of bis(indolyl)methanes at room temperature in a protic solvent.
[Back to top]
PolyHIPEs as Novel Media for Conventional Free Radical
Chemistry
Shengmiao Zhang, Jianding Chen and Victoria T. Perchyonok
The novel materials, polyHIPEs with incorporated tetrasubstituted
ammonium cationic surfactant (CTAB) have been applied to a
broad range of radical precursors in various free radical
transformations in organic and aqueous media. The advantage
of this reagent/ solid phase surfactant combination lies in
its affordability, miniscule toxicity, avoidance of highly
toxic “tin based hydrogen donors” under green
reaction conditions.
[Back to top]
Chemoselective and Efficient Method for Deprotection
of THP and Silyl Ethers with H2O2/
Mn(III) Schiff-Base Complex
Mahmood Tajbakhsh, Rahman Hosseinzadeh, Hamid Golchoubian
and Raheleh Razavian
Mn(III) Schiff-base complex as a catalyst with H2O2
was applied for oxidative deprotection of THP ethers to the
corresponding carbonyl compounds and conversion of silyl ethers
into the parent alcohols under mild conditions. Chemoselective
cleavage of trimethylsilyl ethers in the presence of t-butyldimethylsilyl
ethers and cleavage of trimethylsilyl ethers in the presence
of tetrahydropyranyl ethers were also achieved with this system.
[Back to top]
Synthesis and Characterization of Two Novel Stigmasterol-Based
Cationic Lipids
Jia Qian, Zhiping Le, Fei Yu and Pinghan Jiang
Two novel stigmasterol-based cationic lipids, Stigmasta-5,22-dien-3-ol,4-[[2-
(dimethylamino)ethyl]amino]-4-oxobutanoate,(3β,22E)-(9CI)
and stigmasta-5,22-dien- 3-ol,4-[[2-(dimethylamino)ethyl]amino](2E)-4-oxobutenoate,
(3β,22E)-(9CI),
were synthesized. These compounds were characterized by mass
spectrometry (MS), nuclear magnetic resonance (NMR) and fourier
transform infrared (FT-IR).
[Back to top]
Efficient One-Step Synthesis of Substituted-pyrazolo[3,4-b]pyridine
from Substituted-3-cyano-2(1H)-pyridone
Yasser S. Abdel-Ghany, Aly A. Hazzaa, Mohamad M. Abdul
Ghani and Zahra A. Kassem
An efficient one-step conversion of 4-phenyl-5-ethoxycarbonyl-3-cyano-6-metlyl-2(1H)-pyridone
(1) into ethyl 3-amino-6-methyl-4-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate
(7) is described. An unusual hydrazine mediated
decarboxylation of 7 into 3-amino-6-methyl-4-phenyl-1H-pyrazolo[3,4-b]pyridine
(8) is reported. The structure of 8
was confirmed by spectral and chemical investigations. A plausible
reaction mechanism for the formation of the unexpected product
8 is proposed.
[Back to top]
A Simple and Efficient One-Pot Synthesis of Spirooxindoles
in Water Under Microwave Irradiation Conditions
Song-Lei Zhu, Shun-Jun Ji , Kai Zhao and Yong Zhang
A simple and efficient method for the synthesis of spirooxindoles
derivatives by one-pot reactions of isatins, activated methylene
reagents and activated carbonyl compounds in water under microwave
irradiation was reported. This protocol has the advantages
of short reaction time, high yields, easy work-up procedure
and environmentally benign characters.
[Back to top]
Phenolic Glycosides from Viburnum fordiae Hance and
their Antioxidant Activities
Bin Wu, Xintian Zheng, Haibin Qu and Yiyu Chen
Chemical investigation of the leaves of Viburnum
fordiae Hance has resulted in the isolation and characterization
of a novel phenolic glycoside fordioside (1),
and three known phenolic glycosides including stilbene glycoside
and lignan glycoside (2-4). These structures
were established on the basis of analysis of spectroscopic
evidence. The antioxidant activities of all phenolic glycosides
were also evaluated.
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