|
Letters in Organic Chemistry
ISSN: 1570-1786
Letters in Organic Chemistry
Volume 6, Number 7, October 2009
Contents
Etherification of Diarylmethanols and 1-Phenylalkan-1-ols
Over Platinum on Carbon Pp. 515-525
Thies Thiemann
[Abstract] [Purchase
Article]
Synthesis of a Novel Heterocyclic System
- Pyrimido[5',4':5,6] thiopyrano [2,3-b]indole
Pp. 526-528
Jurgis Sudzius and Sigitas Tumkevicius
[Abstract] [Purchase
Article]
The Role of Phase Transfer Catalysis
in the Microwave-Assisted N-Benzylation of Amides,
Imides and N-Heterocycles Pp. 529-534
István Greiner, Fanni Daruny Sypaseuth,
Alajos Grün, Éva Karsai and György
Keglevich
[Abstract] [Purchase
Article]
Heterogeneous Phase Alkylation of Phenols
Making Use of Phase Transfer Catalysis and Microwave Irradiation
Pp. 535-539
György Keglevich, Erika Bálint,
Éva Karsai, Judit Varga, Alajos Grün, Mária
Bálint and István Greiner
[Abstract] [Purchase
Article]
Synthesis and Application of New Modified
Dinucleotide Cap Analog Pp. 540-543
Anilkumar R. Kore and Muthian Shanmugasundaram
[Abstract] [Purchase
Article]
A Convenient One Pot Synthesis of 3-Cyano-9-methyl-2-methylthio-
4-oxo-4H- pyrimido[2,1-b]
pyrimido [4,5-b] Quinoline and its Reactions with
Selected Nucleophiles Pp. 544-548
Sambhaji P. Vartale, Vijay N. Bhosale, Sandeep
V. Khansole and Ramdas N. Katapalle
[Abstract] [Purchase
Article]
A Model for Predicting the Optimal Conditions
for Labeling the Carbohydrates with the Amine Derivatives
by Reductive Amination Pp. 549-551
Zicai Sun, Zheng Wei and Kemei
Wei
[Abstract] [Purchase
Article]
Diastereoselective Darzens Condensations of α-Haloamides:
Influence of Aryl Substituents on Diastereoselectivity
Pp. 552-556
Michael North and Francesca Pizzato
[Abstract] [Purchase
Article]
A Practical Approach Towards Synthesis
of Octahydroquinazolinone Derivatives in Water Pp.
557-559
Hai-Xia Lin, Xiao-Zhen Xie, Xiao-Hong Wang
and Bin He
[Abstract] [Purchase
Article]
Synthesis of Trisubstituted-4H-Pyrans
via Unexpected Cycloaddition of Aldehydes with Acetylenic
Ketones Mediated by DMAP and 2,4- Pentanedione Pp.
560-563
Bin Hu, Qing-Fa Zhou, Kai Tang and
Song Xue
[Abstract] [Purchase
Article]
Ligand-Free Cu-Catalyzed Cyanation of
Aryl Halides with K4[Fe(CN)6]
in Water Pp. 564-567
Yunlai Ren, Shuang Zhao, Xinzhe Tian, Zhifei
Liu, Jianji Wang and Weiping Yin
[Abstract] [Purchase
Article]
An Efficient Method for One-Pot Reductive
Cleavage of Acetals to Primary Alcohols Using a Bimetal Redox
Couple CoCl2.6H2O-Zn
Pp. 568-572
Kuladip Sarma and Amrit Goswami
[Abstract] [Purchase
Article]
Iron-Catalyzed Cross-Coupling Reaction
of Aryl Grignard Reagents 573 with bis(2-bromovinyl)benzenes
Pp. 573-578
Alessandra Operamolla, Omar Hassan Omar,
Francesco Babudri, Michele Vitulli and Gianluca M.
Farinola
[Abstract] [Purchase
Article]
Synthesis and Antimicrobial Activities of Some New
3 (Chlorophenyl-ethyl)-, 3-(Chlorophenylethenyl)- Isocoumarins
and their Dihydro Derivatives Pp. 579-584
Gul S. Khan, G. Qadeer, Nasim H. Rama and
Khalid Mohammed Khan
[Abstract] [Purchase
Article]
A New Method for Halogenation of Aromatic
Compounds By Using Dimethyldioxirane and Tetrabutylammonium
Halides Pp. 585-587
Yean-Jang Lee, Huan-Ting Wu and
Chia-Ning Lin
[Abstract] [Purchase
Article]
Crystal Structure of 9,10-Dipentafluorophenylanthracene
Host System Pp. 588-592
Yoshitane Imai, Kensaku Kamon, Kakuhiro
Kawaguchi, Nobuo Tajima, Tomohiro Sato, Reiko Kuroda and
Yoshio Matsubara
[Abstract]
[Purchase
Article]
Abstracts
[Back to top]
[Purchase
Article]
Etherification of Diarylmethanols and 1-Phenylalkan-1-ols
Over Platinum on Carbon
Thies Thiemann
In the presence of platinum on carbon (Pt/C), diarylmethanols
and donor substituted 1-phenylalkan-1-ols undergo cross-etherification
with primary and secondary alcohols.
[Back to top]
[Purchase
Article]
Synthesis of a Novel Heterocyclic System - Pyrimido[5',4':5,6]
thiopyrano [2,3-b]indole
Jurgis Sudzius and Sigitas Tumkevicius
An efficient protocol for the synthesis of pyrimido[5',4':5,6]thiopyrano[2,3-b]indoles
by the cyclocondensation of 1,3-dihydro-2H-indole-2-thione
with 6-chloropyrimidine-5-carbaldehydes has been developed.
4-Chloro-2-methylthiopyrimido[5',4':5,6]thiopyrano[2,3-b]indole
was found to undergo smooth nucleophilic substitution with
various nucleophiles to give 4-substituted pyrimido[5',4':5,6]thiopyrano[2,3-b]indoles.
[Back to top]
[Purchase
Article]
The Role of Phase Transfer Catalysis in the Microwave-Assisted
N-Benzylation of Amides, Imides and N-Heterocycles
István Greiner, Fanni Daruny Sypaseuth,
Alajos Grün, Éva Karsai and György
Keglevich
The effect of triethylbenzylammonium chloride (TEBAC)
was studied on the outcome of the microwave-assisted solid–liquid
phase N-alkylation of amides, imides and N-heterocycles
using benzyl halides and K2CO3.
It was found that while the benzylation of amides may be somewhat
promoted by the presence of TEBAC, succinimide and benzimidazole
are so reactive that there is no need to use the catalyst.
At the same time, the outcome of the benzylation of phenothiazine
may be significantly influenced by the presence or absence
of TEBAC in respect of N- versus C-alkylation.
[Back to top]
[Purchase
Article]
Heterogeneous Phase Alkylation of Phenols Making Use of Phase
Transfer Catalysis and Microwave Irradiation
György Keglevich, Erika Bálint,
Éva Karsai, Judit Varga, Alajos Grün, Mária
Bálint and István Greiner
The benzylation of cresol was studied under liquid–liquid
and solid–liquid phase transfer catalytic conditions.
Microwave irradiation was useful only in the solid–liquid
phase benzylations. Using acetonitrile as the solvent, the
benzylations were fully O-selective, but complete
conversions were obtained only in the presence of Cs2CO3.
There was no need to use an onium salt. In the absence of
solvent, an O-selectivity of ca. 90% could be obtained
in the presence of an alkali carbonate and an onium salt.
The optimum set of conditions was extended to the reaction
of other phenol derivatives and alkylating agents.
[Back to top]
[Purchase
Article]
Synthesis and Application of New Modified Dinucleotide Cap
Analog
Anilkumar R. Kore and Muthian Shanmugasundaram
We describe synthesis of a chain-terminating mRNA cap
dinucleotide m27,
2'OG[5']ppp[5']m7G
analog. A new dinucleotide cap analog was synthesized with
methyl groups on the both N7
guanine moieties, as well as the 2'-OH of one of the ribose
moiety is reported. The biological validation of triple methylated
cap analog was done with respect to their effects on capping
efficiency, yield of RNAs during in vitro transcription,
and the translational activity of these RNAs upon transfection
into HeLa cells. The RNA capped with the trimethylated analog
(m27,
2'OG[5']ppp[5']m7G)
was translated the most efficiently, with ~ 2.5 -fold more
activity than the conventional cap (m7G[5']ppp[5']G).
[Back to top]
[Purchase
Article]
A Convenient One Pot Synthesis of 3-Cyano-9-methyl-2-methylthio-
4-oxo-4H- pyrimido[2,1-b]
pyrimido [4,5-b] Quinoline and its Reactions with
Selected Nucleophiles
Sambhaji P. Vartale, Vijay N. Bhosale, Sandeep
V. Khansole and Ramdas N. Katapalle
3-Amino-8-methyl pyrimido [4,5-b] quinoline
(1) in N,N-dimethyl formamide (DMF) and anhydrous potassium
carbonate reacted with ethyl-2-cyano-3,3-bismethyl thioacrylate
2 to afford novel heterocyclic compound 3-cyano-9-methyl-2-methylthio-4-oxo-4H-pyrimido
[4,5-b] quinoline 3. The latter
were further reacted with selected N-, O- and C- nucleophiles
such as arylamines, substituted phenols, heterylamines and
compounds with an active methylene group.
[Back to top]
[Purchase
Article]
A Model for Predicting the Optimal Conditions for Labeling
the Carbohydrates with the Amine Derivatives by Reductive
Amination
Zicai Sun, Zheng Wei and Kemei
Wei
The reaction of the primary amine species with the carbohydrate’s
reducing end moieties is a kind of special reductive amination
reactions which need acid catalysis. The rate equation and
selectivity equation of this kind of reactions were given
by the kinetic and thermodynamic theories, which can predict
the influence of the reaction temperature, pKα
of used amine and pH on the reaction rate and yield. Based
on this theoretical model, researchers can design their route
and set the appropriate reaction conditions for immobilization
of the carbohydrates or preparation of the carbohydrate conjugates.
[Back to top]
[Purchase
Article]
Diastereoselective Darzens Condensations of α-Haloamides:
Influence of Aryl Substituents on Diastereoselectivity
Michael North and Francesca Pizzato
N,N-Diaryl α-haloamides
undergo Darzens condensations with aldehydes induced by metal
hydroxides. The diastereoselectivity of epoxide formation
is strongly influenced by the electronic properties of the
arylamide, which can be rationalised on the basis of the acidity
of the substrate hydrogens and hence on reaction occurring
under kinetic or thermodynamic control.
[Back to top]
[Purchase
Article]
A Practical Approach Towards Synthesis of Octahydroquinazolinone
Derivatives in Water
Hai-Xia Lin, Xiao-Zhen Xie, Xiao-Hong Wang
and Bin He
A simple, efficient and green procedure has been developed
for the synthesis of octahydroquinazolinone derivatives by
Biginelli-type three-component cyclocondensation reactions
of cyclic β-diketones,
aldehydes and (thio)urea with p-TsOH catalysis in
water.
[Back to top]
[Purchase
Article]
Synthesis of Trisubstituted-4H-Pyrans via Unexpected
Cycloaddition of Aldehydes with Acetylenic Ketones Mediated
by DMAP and 2,4- Pentanedione
Bin Hu, Qing-Fa Zhou, Kai Tang and
Song Xue
A cycloaddition of aldehydes and acetylenic ketones mediated
by 4-dimethylaminopyridine and 2,4-pentanedione is reported.
The method supplies a facile way to synthesize 3,4,5-trisubstituted-4H-pyrans
in moderate to good yields under mild conditions.
[Back to top]
[Purchase
Article]
Ligand-Free Cu-Catalyzed Cyanation of Aryl Halides with K4[Fe(CN)6]
in Water
Yunlai Ren, Shuang Zhao, Xinzhe Tian, Zhifei
Liu, Jianji Wang and Weiping Yin
A simple methodology for Cu-catalyzed cyanation of aryl
halides with K4[Fe(CN)6]
was developed with water as the solvent in conjunction with
ligand-free Cu(OAc)2•H2O
as the catalyst. The suggested methodology is applicable to
cyanation of a wide range of aryl iodides and activated aryl
bromides, and allows the catalyst to be reused six times with
a very slight change in the catalytic activity.
[Back to top]
[Purchase
Article]
An Efficient Method for One-Pot Reductive Cleavage of Acetals
to Primary Alcohols Using a Bimetal Redox Couple CoCl2.6H2O-Zn
Kuladip Sarma and Amrit Goswami
Acyclic or cyclic O,O-acetals and O,S-acetals underwent
reductive cleavage to give primary alcohols efficiently on
treatment with Zn-CoCl2.6H2O-bimetal
redox system in dry tetrahydrofuran at ambient temperature
to give good to excellent yields.
[Back to top]
[Purchase
Article]
Iron-Catalyzed Cross-Coupling Reaction of Aryl Grignard Reagents
573 with bis(2-bromovinyl)benzenes
Alessandra Operamolla, Omar Hassan Omar,
Francesco Babudri, Michele Vitulli and Gianluca M.
Farinola
Fe(acac)3 has been used
as the catalyst in cross-coupling reactions of aryl Grignard
reagents with 1,4-bis(2-bromovinyl)benzenes affording bis(2-arylvinyl)benzenes.
Effects of alkoxy substituents on both reactants and of the
temperature on the reaction outcome are investigated.
[Back to top]
[Purchase
Article]
Synthesis and Antimicrobial Activities of Some New
3 (Chlorophenyl-ethyl)-, 3-(Chlorophenylethenyl)- Isocoumarins
and their Dihydro Derivatives
Gul S. Khan, G. Qadeer, Nasim H. Rama and
Khalid Mohammed Khan
The bioactive 3-(chlorophenylethyl)- and 3-(chlorophenylethenyl)-isocoumarins
were synthesized by the condensation of simple homophthalic
acid with 3-chlorophenylpropionoyl chlorides and chlorocinnamoyl
chlorides, respectively. Alkaline hydrolysis of these isocoumarins
gave the respective keto-acids. (dl)-3,4-Dihydroisocoumarins
were obtained by the reduction of the keto-acids to racemic
hydroxyl-acids, followed by cyclodehydration using acetic
anhydride. These compounds were tested for their antimicrobial
and cytotoxicity (Brine shrimp lethality) bioassay. Bioassay
indicated that some compounds show good antimicrobial activities
and positive lethality.
[Back to top]
[Purchase
Article]
A New Method for Halogenation of Aromatic Compounds By Using
Dimethyldioxirane and Tetrabutylammonium Halides
Yean-Jang Lee, Huan-Ting Wu and
Chia-Ning Lin
In this presentation the novel regioselective halogenation
of arenes or phenols with dimethyldioxirane and Bu4NX
is described. The results showed that a new, versatile and
mild method can be utilized for preparation of aryl halides
starting with arenes or phenols. Finally, this aryl halide
forming methodology is applicable to structurally more complex
flavonoids.
[Back to top]
[Purchase
Article]
Crystal Structure of 9,10-Dipentafluorophenylanthracene Host
System
Yoshitane Imai, Kensaku Kamon, Kakuhiro
Kawaguchi, Nobuo Tajima, Tomohiro Sato, Reiko Kuroda and
Yoshio Matsubara
Guest molecules (benzene and 1,4-dioxane) can be incorporated
into 9,10-dipentafluorophenylanthracene (DPFPA) by tuning
the arrangement of its one-dimensional (1D) column-like structure
with CF-π
interactions of its pentafluorophenyl group in the solid state.
The two guest molecules are trapped in cavities due to benzene-anthracene
edge-to-face and CH-π
interactions with DPFPA, respectively.
|
