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Letters in Organic Chemistry
ISSN: 1570-1786
Letters in Organic Chemistry
Volume 4, Number 1, January 2007
Synthesis of Novel Heterocyclic Prostaglandin Analogues
Pp. 1-3
Francisco C. Biaggio, Alessandra R. Rufino and Marcela
C.F. Silveira
[Abstract] [Full
Text Article]
Enantioselective Synthesis of 2,3-Disubstituted Piperidines
Pp. 4-6
Michael Calosso, Mathieu Wagner, Thomas Gendrineau and
Morgane Petit, Catherine Kadouri-Puchot and Luc Dechoux
[Abstract] [Full
Text Article]
Selenium-Containing Heterocycles From Isoselenocyanates:
Synthesis of Ethyl 4-oxo-2-amino-4,5-dihydroselenophene-3
carboxylates Pp. 7-12
Geoffroy L. Sommen, Anthony Linden and Heinz Heimgartner
[Abstract] [Full
Text Article]
Miyaura-Suzuki Cross Coupling Reactions: The Role
of Pd/CaCO3 as Catalyst Reservoir Pp.
13-15
Bianca L. Oliveira and Octavio A. C. Antunes
[Abstract] [Full
Text Article]
L-Proline as an Efficient Organo-Catalyst
for the Synthesis of Polyhydroquinoline Via Multicomponent
Hantzsch Reaction Pp. 16-9
Nandkishor N. Karade, Vishnu H. Budhewar, Sandeep V. Shinde
and Wamanrao N. Jadhav
[Abstract] [Full
Text Article]
Direct Synthesis of Weinreb Amides from Carboxylic
Acids Using Triphosgene Pp. 20-22
Ki-Jong Han and Misoo Kim
[Abstract] [Full
Text Article]
One-Pot Synthesis of 1,2,3-Triazoles from Benzyl and
Alkyl Halides, Sodium Azide and Alkynes in Water Under Transition
Metal-Catalyst Free Reaction Conditions Pp. 23-26
Pinhua Li and Lei Wang
[Abstract] [Full
Text Article]
Oxidation Reaction of Bis-Quinolizidine System: Synthesis
of New 2-Methyl-17-Oxosparteine and 2-Methyl-α-Isosparteine
Pp. 27-31
[Abstract] [Full
Text Article]
New and Efficient Synthesis of 2-Alkoxyapomorphines
Pp. 32-34
Sándor Berényi, Csaba Csutorás, Attila
Sipos and Zsuzsanna Gyulai
[Abstract] [Full
Text Article]
Microwave-Promoted Ring Opening Reaction of Azalactones
Pp. 35-38
Ricardo H. Valdés, Donato A.G. Aranda, Heiddy M.
Alvarez and Octavio A.C. Antunes
[Abstract] [Full
Text Article]
Multicomponent Synthesis of 3,4-Dihydropyrimidin-2-(1H)-Ones
with a Cu/Silica Xerogel Composite Catalyst Pp. 39-42
Dennis Russowsky, Edilson V. Benvenutti, Gabriela S. Roxo
and Fábio Grasel
[Abstract] [Full
Text Article]
Improved Synthesis of Benzotriazoles and 1-Acylbenzotriazoles
by Ultrasound Irradiation Pp. 43-46
Claudio M.P. Pereira, Hélio A. Stefani, Karla P.
Guzen and Aline T.G. Orfão
[Abstract] [Full
Text Article]
Multicomponent Solvent-Free Cyclocondensation/Glycosylation
Strategy for Thiazolo-s-triazine N-Nucleosides
Pp. 47-50
Lal Dhar Singh Yadav, Vijai Kumar Rai and Seema Yadav
[Abstract] [Full
Text Article]
Reaction between N-(Thio)Phosphoryl Imines
and Diethylzinc Pp. 51-53
Xinpeng Ma, Chungui Wang, Xinyuan Xu, Guofeng Zhao, Zhenghong
Zhou and Chuchi Tang
[Abstract] [Full
Text Article]
Aza-Michael Addition of Amines to Activated Alkenes
Catalyzed by Silica Supported Perchloric Acid Under a Solvent-Free
Condition Pp. 54-59
Chinmoy Mukherjee and Anup Kumar Misra
[Abstract] [Full
Text Article]
K5CoW12O40.3H2O:
Highly Efficient Heterogeneous Catalyst for the Synthesis
of α-Aminonitriles
Pp. 60-63
E. Rafiee, A. Azad and M. Joshaghani
[Abstract] [Full
Text Article]
Polyvinylpolypyrrolidone-Bromine Complex, Mild and
Efficient Polymeric Reagent for Selective Deprotection and
Oxidative Deprotection of Silylethers Pp. 64-67
Moslem Mansour Lakouraj and Masoud Mokhtary
[Abstract] [Full
Text Article]
Ionic Liquid/Silica Sulfuric Acid Promoted Fast Synthesis
of a Biginelli-Like Scaffold Reaction Pp. 68-71
Ahmad Shaabani, Afshin Sarvary, Abbas Rahmati and Ali
Hossein Rezayan
[Abstract] [Full
Text Article]
Nucleophilic Substitution Reactions in Ionic Liquid:
Towards a Real Continuous-Flow Process for Synthesis of Alkyl
Bromides and Cyanides Pp. 72-74
Zhiming Wang, Zhe Li and Weiliang Bao
[Abstract] [Full
Text Article]
Montmorillonite K10 Catalyzed Selective Oxidation
of Sulfides to Sulfoxides Using Hydrogen Peroxide
Pp. 75-79
Moslem Mansour Lakouraj, Mahmood Tajbakhsh and Hamed Tashakkorian
[Abstract] [Full
Text Article]
Abstracts
[Back to top]
Synthesis of Novel Heterocyclic Prostaglandin Analogues
Francisco C. Biaggio, Alessandra R. Rufino and Marcela
C.F. Silveira
[Full
Text Article]
New prostaglandins analogues, containing heteroatoms in the
cyclopentane ring were synthesized. The key step in the synthesis
was the preparation of the five-membered ring starting from
L-cysteine ethyl ester hydrochloride. The addition of the
alkyl groups at C-15 position was also performed.
[Back to top]
Enantioselective Synthesis of 2,3-Disubstituted Piperidines
Michael Calosso, Mathieu Wagner, Thomas Gendrineau and
Morgane Petit, Catherine Kadouri-Puchot and Luc Dechoux
[Full
Text Article]
Chiral derivative 3 has been recognized as
a precursor of enantiopure 2,3-disubstituted piperidines.
A study concerning the chemoselective reduction, using BH3.Me2S,
of highly functionalised compounds 6 and
N-BOC aminoacid 12 is reported.
[Back to top]
Selenium-Containing Heterocycles From Isoselenocyanates:
Synthesis of Ethyl 4-oxo-2-amino-4,5-dihydroselenophene-3
carboxylates
Geoffroy L. Sommen, Anthony Linden and Heinz Heimgartner
[Full
Text Article]
Aryl and alkyl isoselenocyanates 2 react
with ethyl γ-chloroacetoacetate
(1) in the presence of triethylamine to give
the corresponding 4-oxo-2-amino-4,5-dihydroselenophene-3-carboxylates
4a-f in moderate to good yields.
[Back to top]
Miyaura-Suzuki Cross Coupling Reactions: The Role
of Pd/CaCO3 as Catalyst Reservoir
Bianca L. Oliveira and Octavio A. C. Antunes
[Full
Text Article]
Miyaura-Suzuki reaction was carried out in water-ethanol solutions
by using Pd/CaCO3
as catalyst. Very good yields were obtained using different
bases, phosphates or carbonates. The catalyst was recycled
up to seven times without any loss of activity. To evidence
the presence of Pd(II) in solution as the true catalyst, the
solids were removed by decantation and the reaction products
were extracted with hexane. The water-ethanol solution was
recycled and kept catalytic activity.
[Back to top]
L-Proline as an Efficient Organo-Catalyst
for the Synthesis of Polyhydroquinoline Via Multicomponent
Hantzsch Reaction
Nandkishor N. Karade, Vishnu H. Budhewar, Sandeep V. Shinde
and Wamanrao N. Jadhav
[Full
Text Article]
L-Proline has been found as an effective catalyst
for the one pot synthesis of polyhydroquinoline derivatives
via four component Hantzsch reaction. This method provides
several advantages such as being environmentally benign, possessing
high yields with increased variations of the substituents
in the product and preparative simplicity.
[Back to top]
Direct Synthesis of Weinreb Amides from Carboxylic
Acids Using Triphosgene
Ki-Jong Han and Misoo Kim
[Full
Text Article]
Weinreb amides were conveniently prepared in high yields by
reaction of carboxylic acids with N,O-dimethylhydroxylamine
hydrochloride at room temperature using triphosgene as an
acid activator in the presence of triethylamine.
[Back to top]
One-Pot Synthesis of 1,2,3-Triazoles from Benzyl and
Alkyl Halides, Sodium Azide and Alkynes in Water Under Transition
Metal-Catalyst Free Reaction Conditions
Pinhua Li and Lei Wang
[Full
Text Article]
In the absence of any catalysts and additives, one-pot synthesis
of 1,2,3-triazoles from benzyl and alkyl halides, sodium azide
and alkynes in water was developed. The reactions of terminal
arylalkynes, sodium azide with benzyl chlorides and bromides
generated the corresponding regiospecific 1,4-disubstituted
triazoles in excellent yields, but terminal aliphatic alkynes
afforded the mixture of regioisomers (1,4-disubstituted and
1,5-disubstituted triazoles). For the reactions of primary
aliphatic bromides, sodium azide and phenylacetylene, the
ratio of 1,4- to 1,5-isomers ranging from 57 : 43 to 100 :
0 indicated 1,4-disubstituted regioselectivity of the reaction
was raised with the increase of the carbon chain in primary
aliphatic bromides. The present procedure does not require
isolation of the azide intermediates and may prove to be especially
useful when unstable low-molecular weight and polyvalent azides
are needed. Furthermore, it is an ideal environmental benign
reaction system only using water as solvent without any catalysts
and additives.
[Back to top]
Oxidation Reaction of Bis-Quinolizidine System: Synthesis
of New 2-Methyl-17-Oxosparteine and 2-Methyl-α-Isosparteine
[Full
Text Article]
Susceptibilities of two bis-quinolizidine systems: 2-methylsparteine
and 2-phenylsparteine to oxidation reaction using K3Fe(CN)6,
KMnO4
and Hg(CH3COO)2
have been determined. Of these two derivatives only 2-methylsparteine
has been found to undergo oxidation giving new 2-methyl-17-oxosparteine
and 2-methyl-α-isosparteine.
The structures of the new compounds have been established
by IR, MS and NMR spectroscopies. The experimental evidence
has been supported by DFT calculations.
[Back to top]
New and Efficient Synthesis of 2-Alkoxyapomorphines
Sándor Berényi, Csaba Csutorás, Attila
Sipos and Zsuzsanna Gyulai
[Full
Text Article]
A novel synthetic route has been developed for the preparation
of pharmacologically remarkable (R)-(–)-2-methoxyapomorphine
(2) and other 2-alkoxyapomorphines 8-10.
[Back to top]
Microwave-Promoted Ring Opening Reaction of Azalactones
Ricardo H. Valdés, Donato A.G. Aranda, Heiddy M.
Alvarez and Octavio A.C. Antunes
[Full
Text Article]
α,β-Dehydroamino
amides are important intermediates for the synthesis of biologically
active molecules. A rapid procedure is reported for the synthesis
of α,β-dehydroamino
amides from azalactones under MW radiation. Azalactones were
produced via Erlenmeyer reaction and submitted to ring opening
reactions under MW during 15-30 min. Over 90% yields were
obtained.
[Back to top]
Multicomponent Synthesis of 3,4-Dihydropyrimidin-2-(1H)-Ones
with a Cu/Silica Xerogel Composite Catalyst
Dennis Russowsky, Edilson V. Benvenutti, Gabriela S. Roxo
and Fábio Grasel
[Full
Text Article]
The efficient multicomponent synthesis of 3,4-dihydropyrimidin-2(1H)-ones
promoted by a heterogeneous Cu/silica xerogel composite is
presented herein. This composite was synthesized by the sol-gel
methodology employing CuCl2 as the metal source.
The catalyst can be easily recovered and reused in subsequent
reactions.
[Back to top]
Improved Synthesis of Benzotriazoles and 1-Acylbenzotriazoles
by Ultrasound Irradiation
Claudio M.P. Pereira, Hélio A. Stefani, Karla P.
Guzen and Aline T.G. Orfão
[Full
Text Article]
Some 1H-benzotriazoles have been synthesised in good
yields in short times by reaction of o-phenylenediamine
with sodium nitrite in acetic acid under ultrasound irradiation.
Also, the ultrasound-assisted preparation of 1-acylbenzotriazoles
is described.
[Back to top]
Multicomponent Solvent-Free Cyclocondensation/Glycosylation
Strategy for Thiazolo-s-triazine N-Nucleosides
Lal Dhar Singh Yadav, Vijai Kumar Rai and Seema Yadav
[Full
Text Article]
A green protocol involving novel three-component one-pot cyclocondensation
reactions of 2-amino-4-aryl-thiazoles, aromatic aldehydes
and ammonium thiocyanate under solvent-free microwave irradiation
(MWI) conditions expeditiously yields thiazolo-s-triazine
nucleobases, which afford the corresponding pyrano N-nucleosides
on I2 promoted glycosylation with 1,2,3,4-tetra-O-acetyl-β-D-ribo-/xylopyranose
under MWI followed by deacetylation.
[Back to top]
Reaction between N-(Thio)Phosphoryl Imines
and Diethylzinc
Xinpeng Ma, Chungui Wang, Xinyuan Xu, Guofeng Zhao, Zhenghong
Zhou and Chuchi Tang
[Full
Text Article]
The reaction between N-(thio)phosphoryl imines and
diethylzinc was investigated in detail. For the imines bearing
at least one P-O single bond, the corresponding reduction
product was formed in excellent yield in nonpolar solvent
toluene. In polar solvent, the reduction product was generated
accompanied with partial formation of the alkylation product.
The corresponding ethylating product became the predominant
product in the presence of strong coordinative additive, such
as N,N,N’,N’-tetramethylethane-1,2-diamine
(TMEDA).
[Back to top]
Aza-Michael Addition of Amines to Activated Alkenes
Catalyzed by Silica Supported Perchloric Acid Under a Solvent-Free
Condition
Chinmoy Mukherjee and Anup Kumar Misra
[Full
Text Article]
An efficient aza-Michael addition of amines to a series of
α,β-unsaturated
ketones, carboxylic esters, nitriles and chalcones has been
carried out using perchloric acid supported over silica gel
(HClO4-SiO2) at room temperature in
high yields under solvent-free reaction conditions.
[Back to top]
K5CoW12O40.3H2O:
Highly Efficient Heterogeneous Catalyst for the Synthesis
of α-Aminonitriles
E. Rafiee, A. Azad and M. Joshaghani
[Full
Text Article]
One-pot three-component condensation of aldehydes or ketones,
amines and trimethylsilyl cyanide was accomplished in the
presence of a catalytic amount of K5CoW12O40.3H2O
as an efficient and reusable catalyst.
[Back to top]
Polyvinylpolypyrrolidone-Bromine Complex, Mild and
Efficient Polymeric Reagent for Selective Deprotection and
Oxidative Deprotection of Silylethers
Moslem Mansour Lakouraj and Masoud Mokhtary
[Full
Text Article]
Mild and convenient method for deprotection and direct oxidative
deprotection of silyl ethers to the corresponding hydroxy
and carbonyl compounds is described using polyvinylpolypyrrolidone-bromine
complex (PVPP-Br2). Selective oxidative deprotection
of benzylic silyl ethers in the presence of primary aliphatic
alcohols was also achieved at room temperature.
[Back to top]
Ionic Liquid/Silica Sulfuric Acid Promoted Fast Synthesis
of a Biginelli-Like Scaffold Reaction
Ahmad Shaabani, Afshin Sarvary, Abbas Rahmati and Ali
Hossein Rezayan
[Full
Text Article]
Biginelli-like scaffolds were synthesized in good yields by
a three-component condensation reaction of 5,5-dimethyl-1,3-cyclohexanedione,
an aldehyde and urea, N-methylurea or thiourea in
1-butyl-3-methylimidazolium bromide ([bmim]Br) as ionic liquid
(IL) in the presence of silica sulfuric acid (SSA) as solid
acid catalyst at 100 °C within less than 2 hours.
[Back to top]
Nucleophilic Substitution Reactions in Ionic Liquid:
Towards a Real Continuous-Flow Process for Synthesis of Alkyl
Bromides and Cyanides
Zhiming Wang, Zhe Li and Weiliang Bao
[Full
Text Article]
A real continuous-flow process for synthesis of alkyl bromides
or cyanides was demonstrated by nucleophilic substitution
reactions of tosylates with bromide and/or cyanide conducted
in ionic liquid 1-ethyl-3-methylimidazolium tosylate. The
process provides higher yields and shorter reaction time and
is easily upgraded to large scale.
[Back to top]
Montmorillonite K10 Catalyzed Selective Oxidation
of Sulfides to Sulfoxides Using Hydrogen Peroxide
Moslem Mansour Lakouraj, Mahmood Tajbakhsh and Hamed Tashakkorian
[Full
Text Article]
A clean and highly selective oxidation of sulfides to sulfoxides
with 35% hydrogen peroxide catalyzed by Montmorillonite K10
in methanol is described. A series of structurally different
sulfides were oxidized selectively at room temperature in
excellent yields. This reaction is very simple and proceeds
without over-oxidation under mild condition, and shows many
advantages over the existing methodologies. Using this procedure,
sulfides bearing functional groups such as hydroxyl, methoxy,
amino, nitrile, aldehyde, and olefinic double bond remained
intact. |
