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Letters in Organic Chemistry
ISSN: 1570-1786
Letters in Organic Chemistry
Volume 5, Number 2, March 2008
Contents
A Novel and Expeditious Approach to Symmetrical and
73 Unsymmetrical 5,5-Spiroimide Building Blocks
Pp. 73-78
Iyad Allous, Sébastien Comesse and Aadm Daïch
[Abstract]
A New, Readily Available Double-Component System for Asymmetric
Henry Reaction Pp. 79-81
Wuzu Ha and Zixing Shan
[Abstract]
Indium Trichloride Catalysed Imino Diels-Alder Reaction of
Imesatins: A Facile Synthesis of Novel Spirooxindole 1H
–pyrano[2,3-c ]quinolines Pp. 82-86
E. Ramesh, E. Elamparuthi and R. Raghunathan
[Abstract]
Synthesis of 6-Amino-2,3-Dimethylpyrimido[4,5
e][1,2,4]Triazine-8- One: An Inhibitor of Dihydropteridin
Reductase (DHPR) Pp. 87-90
Jeonghee Kang and Ruel Z. B. Desamero
[Abstract]
Regiospecific Synthesis of 5-Trichloromethyl-1H-Pyrazole
and 1H-Pyrazole-5-Carboxylic Ester Derivatives
Pp. 91-97
Sidnei Moura, Alex F.C. Flores, Favero R. Paula, Ernani
Pinto, Pablo Machado and Marcos A.P. Martins
[Abstract]
Concise Synthesis of Benzoindolizidine Derivatives
and Bioactivity Evaluation Pp. 98-102
Mingbo Cui, Kailiang Wang, Qingmin Wang and Runqiu Huang
[Abstract]
Synthesis of Bicyclic Aryl Thiazolines with Selective Anti
Proliferative Effects on Human Cancer Cell Lines
Pp. 103-109
Rakesh K. Singh, Thilo S. Lange, Kyu K. Kim, Ajay P. Singh,
Russell Hopson, Nicholi Vorsa and Laurent Brard
[Abstract]
Ring Closing Metathesis as an Efficient
Protocol for the Stereoselective Synthesis
of Spiro C-Linked 4-Deoxy Disaccharides
Pp. 110-115
Jakkidi J. Reddy, Asra Begum, Pagadala Jayaprakash, Gangavaram
V.M. Sharma and Ajit C. Kunwar
[Abstract]
Phosphomolybdic Acid Supported on Silica Gel as Mild, Efficient
and Cost-Effective Catalyst for Chemoselective Protection
of Amines with di-tert-Butyl Dicarbonate
Pp. 116-119
J.S. Yadav, Y. Gopala Rao, A. Ramesh Reddy, A.V. Narsaiah,
and B.V. Subba Reddy
[Abstract]
Solvent-Free Amination of Heteroaromatic Chlorides
Pp. 120-124
Erwan Le Gall, Stéphane Sengmany, Corinne Gosmini,
Jacques Périchon and Pascal Retailleau
[Abstract]
In Situ Synthesis of Benzyl Chloromethyl Ether and
its Use for the Protection and Deprotection of Bifunctional
Hydroxyl Compounds Pp. 125-127
Javid H. Zaidi, Khalid M. Khan, Sadullah Mir, Naseem Iqbal
Gunjial and M. Arfan
[Abstract]
A Novel Approach to the Synthesis of Highly Functionalized
Thiophenes Using Isocyanides Catalyzed Reaction of Acetylenic
Esters with 3-Mercapto-2 Butanone Pp. 128-132
Robabeh Baharfar, Roghayeh Hossein nia and Seyed Meysam
Baghbanian
[Abstract]
A Synthesis of a New Pyrano[3,2-c] Quinolinedione
Derivative Assisted by Microwaves Pp. 133-136
George Bratulescu
[Abstract]
Microwave Assisted Solvent-Free Oxidation
of Organic Halides Using Aqueous Hydrogen Peroxide
Pp. 137-139
Jitender M. Khurana and Sanjay Kumar
[Abstract]
An Efficient One-Pot, Two-Step Synthesis of Cyclobuxophyllinine
M from Cyclovirobuxine D in Aqueous Media Pp. 140-141
Hai-Feng Liu, Xiao-Qing Wu, Yan-Bing Duan, Bin Gu and
Min Ji
[Abstract]
An Expedient One-Pot Synthesis of 3,4-Dihydropyrimidin
2(1H)-Ones and -Thiones Catalyzed by ZIRCONIA Nanopowder.
An Improved Protocol for the Biginelli Cyclocondensation Compounds
in ‘Dry Media’ Pp. 142-147
Mannathusamy Gopalakrishnan, Purusothaman Sureshkumar,
Jeyaraman Thanusu, Vijayakumar Kanagarajan and Muthuvel R.
Ezhilarasi
[Abstract]
Reductive Amination of Aldehydes and Ketones
with Xylylene Ionene Bound Borohydride as a Novel Polymer
Supported Reducing Agent Pp. 148-152
Mahmood Tajbakhsh, Moslem Mansour Lakouraj and Majid Shabani
Mahalli
[Abstract]
HClO4-SiO2:
A Highly Efficient and Recyclable Catalyst for the Selective
α-Bromination
of Carbonyl Compounds Using N-Bromosuccinimide
Pp. 153-157
Raman Gupta, Monika Gupta, Satya Paul, Rajive Gupta and
André Loupy
[Abstract]
Abstracts
[Back to top]
A Novel and Expeditious Approach to Symmetrical
and Unsymmetrical 5,5-Spiroimide Building Blocks
Iyad Allous, Sébastien Comesse and Aadm Daïch
Symmetrical and unsymmetrical spiro-bis-imides and corresponding
3-methoxycarbonyl succinimides were prepared in very good
yields starting from dimethyl malonate and suitable α-bromoacetamides
in a one-pot procedure or two-steps sequence, respectively.
The mechanistic aspects of these transformations were also
discussed.
[Back to top]
A New, Readily Available Double-Component System for Asymmetric
Henry Reaction
Wuzu Ha and Zixing Shan
A new, readily available double-component catalytic system
for asymmetric Henry reaction has been discovered. The aromatic
aldehydes reacted with nitromethane in THF under catalysis
of threo-(1S, 2S)-TDMANP-Cu(OAc) 2H2O
system to furnish β-nitro
alcohols in good yields and up to 79% ee. This methodology
is air-tolerant and easily operative, and the chiral amino
alcohol can be conveniently synthesized from inexpensive chiral
starting material.
[Back to top]
Indium Trichloride Catalysed Imino Diels-Alder Reaction of
Imesatins: A Facile Synthesis of Novel Spirooxindole 1H
–pyrano[2,3-c ]quinolines
E. Ramesh, E. Elamparuthi and R. Raghunathan
A novel method for the construction of spirooxindole
via imino Diels-Alder reaction of in situ generated
isatin imine with dihydropyran is reported. InCl3
efficiently catalyzes the reaction to afford cis- and trans-diastereisomers
in fairly good yields
[Back to top]
Synthesis of 6-Amino-2,3-Dimethylpyrimido[4,5 e][1,2,4]Triazine-8-
One: An Inhibitor of Dihydropteridine Reductase (DHPR)
Jeonghee Kang and Ruel Z. B. Desamero
Study of synthetic approaches for precursors and an inhibitor
of DHPR, 6-amino-2,3- dimethylpyrimido[4,5-e][1,2,4]triazine-8-one,
is reported. Structures of precursors and the inhibitor were
confirmed by 1H NMR, 13C
NMR, and ESI-MS measurements.
[Back to top]
Regiospecific Synthesis of 5-Trichloromethyl-1H-Pyrazole
and 1H-Pyrazole-5-Carboxylic Ester Derivatives
Sidnei Moura, Alex F.C. Flores, Favero R. Paula, Ernani
Pinto, Pablo Machado and Marcos A.P. Martins
Reaction of 1,1,1-trichloro-4-methoxy-3-penten-2-one
(1) with hydrazines (2a-h) (NH2NHR,
R = H, Me, t-Bu, Ph, 4-NO2-C6H4,
C6F5,
CO2Me, CONH2)
under differing conditions regiospecifically affords different
pyrazole derivatives, 3-methyl-5-trichloromethyl-5-hydroxy-4,5-dihydropyrazoles
(3a, d-h), 3-methyl-5-trichloromethyl-1H-pyrazoles
(4a,b,d-g) and 5-carboxyethyl-3-methyl-1H-pyrazoles
(5a-e). The structural assignments were based
on the analysis of their 1H/13C
NMR and ESI-MS data.
[Back to top]
Concise Synthesis of Benzoindolizidine Derivatives and Bioactivity
Evaluation
Mingbo Cui, Kailiang Wang, Qingmin Wang and Runqiu Huang
Due to the profound cytotoxicities and interesting biochemical
aspects, phenanthroindolizidine alkaloids have received attention
as potential therapeutic leads. To define the features of
the molecule that are essential for their excellent bioactivities,
we have synthesized two hexahydropyrrolo[1,2-b]isoquinolines
and their hydrochloride salts and picrates concisely and evaluated
their antiviral and anticancer activities. We found that the
replacement of the phenanthrene with a benzene in phenanthroindolizidine
alkaloids observably decreased their antiviral and anticancer
activities, and thus the phenanthrene in phenanthroindolizidine
alkaloids is essential for high antiviral and anticancer activities.
[Back to top]
Synthesis of Bicyclic Aryl Thiazolines with Selective Anti
Proliferative Effects on Human Cancer Cell Lines
Rakesh K. Singh, Thilo S. Lange, Kyu K. Kim, Ajay P. Singh,
Russell Hopson, Nicholi Vorsa and Laurent Brard
The novel synthesis of aryl thiazolines (ATZ) is described
and structures established by COSY, HSQC, HMBC and NOESY experiments.
Compounds DCL-ATZ and Me-ATZ
displayed cytotoxic activities against a neuroblastoma, a
platinum-resistant ovarian adenocarcinoma and a prostate adenocarcinoma
cell line. Me-ATZ displayed differential
anti-proliferative effects.
[Back to top]
Ring Closing Metathesis as an Efficient Protocol for th Stereoselective
Synthesis of Spiro C-Linked 4-Deoxy Disaccharides
Jakkidi J. Reddy, Asra Begum, Pagadala Jayaprakash, Gangavaram
V.M. Sharma and Ajit C. Kunwar
Ring closing metathesis protocol on bis-allylic chirons
derived from sugars was utilized for the stereoselective synthesis
of spiro C-linked deoxy disaccharides. Uloses derived
from D-xylose and L-sorbose were converted into bisallylic
derivatives, which on RCM gave the spiro-pyrane rings. The
xylose-derived spiro-pyrane on sequential oxidations was converted
into new deoxy spiro C-disaccharides.
[Back to top]
Phosphomolybdic Acid Supported on Silica Gel as Mild, Efficient
and Cost-Effective Catalyst for Chemoselective Protection
of Amines with di-tert-Butyl Dicarbonate
J.S. Yadav, Y. Gopala Rao, A. Ramesh Reddy, A.V. Narsaiah,
and B.V. Subba Reddy
A variety of amines were protected as their N-Boc
derivatives using phosphomolybdic acid supported on silica
gel as a heterogeneous catalyst. The catalyst is more effective
and highly selective for the protection of amines under mild
conditions and it can be recovered and reused in subsequent
reactions without apparent loss of activity.
[Back to top]
Solvent-Free Amination of Heteroaromatic Chlorides
Erwan Le Gall, Stéphane Sengmany, Corinne Gosmini,
Jacques Périchon and Pascal Retailleau
The coupling of 5-membered heterocyclic amines such as
pyrazole and imidazole derivatives with heteroaromatic chlorides
like 4,7-dichloroquinoline, 2-chlorobenzoxazole and 2-chlorobenzothiazole
has been realized in good yields using very simple solvent-free
conditions.
[Back to top]
In Situ Synthesis of Benzyl Chloromethyl Ether and
its Use for the Protection and Deprotection of Bifunctional
Hydroxyl Compounds
Javid H. Zaidi, Khalid M. Khan, Sadullah Mir, Naseem Iqbal
Gunjial and M. Arfan
In situ synthesis of benzyl chloromethyl ether and its
use to protect bifunctional hydroxyl compounds as benzyloxymethyl
ethers is reported. This methodology was extended to alkylate
the N-protected L-amino acids.
[Back to top]
A Novel Approach to the Synthesis of Highly Functionalized
Thiophenes Using Isocyanides Catalyzed Reaction of Acetylenic
Esters with 3-Mercapto-2 Butanone
Robabeh Baharfar, Roghayeh Hossein nia and Seyed Meysam
Baghbanian
Reaction of 3-mercapto-2-butanone with electron-deficient
acetylenic esters in the presence of tert-butyl isocyanide
leads to dialkyl 4-hydroxy-4,5-dimethyl-4,5-dihydro-2,3 thiophenedicarboxylates.
These alcohols are converted to 2,3-dialkyl-4,5-dimethyl-2,3-tiophenedicarboxylates
in boiling dichloromethane in fairly good yields. (E/Z)
S-Functionalized vinyl sulfides are produced in this reaction
as by- products.
[Back to top]
A Synthesis of a New Pyrano[3,2-c] Quinolinedione Derivative
Assisted by Microwaves
George Bratulescu
A new pyrano[3,2-c] quinolinedione derivative was synthesized
in three steps starting from N-methylanthranilic acid. The
synthesis was accomplished using both conventional thermal
methods and microwave assisted procedures. The syntheses are
more convenient when the microwaves are employed because of
shorter reaction times, the elimination of waste solvents,
and improved chemical yields.
[Back to top]
Microwave Assisted Solvent-Free Oxidation of Organic Halides
Using Aqueous Hydrogen Peroxide
Jitender M. Khurana and Sanjay Kumar
A rapid and highly efficient protocol involving solvent
free oxidation of organic halides using aqueous hydrogen peroxide
under controlled microwave irradiation is described for the
synthesis of carbonyl compounds.
[Back to top]
An Efficient One-Pot, Two-Step Synthesis of Cyclobuxophyllinine
M from Cyclovirobuxine D in Aqueous Media
Hai-Feng Liu, Xiao-Qing Wu, Yan-Bing Duan, Bin Gu and
Min Ji
A highly efficient one-pot, two-step sequential process
consisting of modified Jones oxidation of aqueous cyclovirobuxine
D acetate followed by Ruschig degradation after pH regulation
with saturated aqueous NaOH, provided cyclobuxophyllinine
M in high yield and in a single geometrical isomeric form.
[Back to top]
An Expedient One-Pot Synthesis of 3,4-Dihydropyrimidin 2(1H)-Ones
and -Thiones Catalyzed by ZIRCONIA Nanopowder. An Improved
Protocol for the Biginelli Cyclocondensation Compounds in
‘Dry Media’
Mannathusamy Gopalakrishnan, Purusothaman Sureshkumar,
Jeyaraman Thanusu, Vijayakumar Kanagarajan and Muthuvel R.
Ezhilarasi
A general and practical Green Chemistry route to the
Biginelli cyclocondensation multicomponent reaction had been
carried out by the three-component coupling of β-ketoesters,
various structurally diverse aldehydes including heterocyclic
aldehydes and urea/thiourea in the presence of Zirconia (ZrO2)
nanopowder catalyst in dry media under microwave irradiation
and a comparative study was also done under thermal conditions
giving 3,4-dihydropyrimidin-2(1H)-ones and -thiones
(DHPMs) in excellent yields. Besides, it was highlighted that
ZrO2 nanopowder can be reused
up to six times after simple washing with ethyl acetate, thus
exposing the process economical and environmentally benign.
[Back to top]
Reductive Amination of Aldehydes and Ketones
with Xylylene Ionene Bound Borohydride as a Novel Polymer
Supported Reducing Agent
Mahmood Tajbakhsh, Moslem Mansour Lakouraj and Majid Shabani
Mahalli
An efficient reductive amination of aldehydes and ketones
in the preparation of aliphatic and aromatic secondary and
tertiary amines with xylylene ionene borohydride as a high
capacity polymer supported reducing agent in isopropanol at
reflux under neutral conditions is described. Xylylene ionene
borohydride is easily prepared by mixing an aqueous solution
of xylylene ionene chloride with an alkaline solution of sodium
borohydride at room temperature. The chemoselective reductive
amination in the presence of functional groups such as chloride,
C=C bond, nitro and cyano groups was also achieved. The generality
of reaction was established using variety of aldehydes, ketones
and amines.
[Back to top]
HClO4-SiO2:
A Highly Efficient and Recyclable Catalyst for the Selective
α-Bromination
of Carbonyl Compounds Using N-Bromosuccinimide
Raman Gupta, Monika Gupta, Satya Paul, Rajive Gupta and
André Loupy
Perchloric acid adsorbed onto silica gel (HClO2-SiO2)
was found to be a highly efficient, inexpensive and recyclable
catalyst for the selective α-bromination
of carbonyl compounds using N-bromosuccinimide by
stirring in n-hexane at room temperature under mild
and heterogeneous conditions. |
