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Letters in Organic Chemistry
ISSN: 1570-1786
Letters in Organic Chemistry
Volume 5, Number 5, July 2008
Contents
Synthesis of 1-Aminocyclopropyl-Pentanoic and -Heptanoic
Acid Derivatives Pp. 328-331
Martina Gensini, Laura Quartara and Maria Altamura
[Abstract]
Phenol and Naphthol Oxidation to Quinones with
Hydrogen Peroxide Using Vanadium-Substituted Keggin Heteropoly
Acid as Catalyst Pp. 332-335
Gustavo P. Romanelli, Paula I. Villabrille, Patricia G.
Vázquez, Cármen V. Cáceres and Pietro
Tundo
[Abstract]
Design and Synthesis of Novel Thioether-linked
Carbapenem- Oxazolidinone Hybrids as Potential Antimicrobial
Agents Pp. 336-341
Jianwei Wang, Juan Huang, Yong Wu, Li Hai and Guangming
Wang
[Abstract]
Enantioselective Michael Addition of Nitroolefins
and Cyclohexanones Catalyzed by Novel Pyrrolidine-thiourea
Bifunctional Catalysts with Two Chiral Centers Pp.
342-345
Dongping Cheng and Weiliang Bao
[Abstract]
Palladium-Catalyzed Asymmetric Allylic Substitution Using
Phosphoramidite Ligands Bearing 1,1'-Binaphthyl Skeleton
Pp. 346-348
Yongguang Gao, Xinsheng Li, Weiyi Chen and Dongcheng Xu
[Abstract]
Microwave-Assisted Synthesis of 1,3-Thiazolidin-4-ones and
2 Aryl-1,3-oxathiolan-5-ones Pp. 349-352
Wilson Cunico, Walcimar T. Vellasco Junior, Marcele Moreth
and Claudia R.B. Gomes
[Abstract]
Iodine/EtOH: A Novel and Versatile Catalyst for
the Synthesis of β-Amino
Ketones via Three Component Reaction Pp.
353-359
Jhillu S. Yadav, Basi V.S. Reddy, Kattela S. Shankar,
Kokku Premalatha and Tallapally Swamy
[Abstract]
Synthesis of Sugar β-Amino
Acid Containing Homooligomeric Cyclic Peptides Pp.
360-364
Manuel Andreini, Claude Taillefumier, Brigitte Fernette
and Yves Chapleur
[Abstract]
The Facile and Efficient Three-Component One-Pot
Mannich Type Reaction of Indoles Catalyzed by In(OTf)3
Under Microwave Irradiations Pp. 365-369
Dipak Prajapati, Sunil Gadhwal and Rupam Sarma
[Abstract]
Ultrasound Assisted Selective Reduction of Chalcones
to Dihydrochalcones by Zn/HOAc Pp. 370-373
Liang Zhang, Weige Zhang, Xin Wang, Kai Bao, Guodong Lu
and Jinshun Lin
[Abstract]
A New 6H-Pyran-3-one Scaffold Derived from a C-Glycoside Supporting
Information i-xvii Pp. 374-378
Natalia de la Figuera, Sandra Fiol, Joan C. Fernández,
Pilar Forns, Dolors Fernández-Forner and Fernando Albericio
[Abstract]
Morita-Baylis-Hillman Reaction in Water/Ionic Liquids
under Microwave Irradiation Pp. 379-382
Rodrigo O.M.A. de Souza, Andréa L.F. de Souza,
Tatiana L. Fernández,Aires C. Silva, Vera L.P. Pereira,
Pierre M. Esteves,Mario L.A.A. Vasconcellos and Octavio A.C.
Antunes
[Abstract]
Efficient Synthesis of Aza-Phenanthroindolizidine and Aza
Phenanthro-quinolizidine and Anticancer Activities
Pp. 383-390
Kailiang Wang, Wenlong Wang, Qingmin Wang and Runqiu Huang
[Abstract]
Enantioselective Synthesis of 2, 6-Disubstituted
Dihydropyrone Derivatives Catalyzed by TiCl4
/ BINOL/RONa System
Pp. 391-395
Yuan-Cong Zhao, Ji Zhang, Na Wang, Hong Yu, Xin-Bing
Yang, Shan Yong Chen and Xiao-Qi Yu
[Abstract]
Rapid Microwave-Promoted Solvent-Free Synthesis
of Zincke’s Salts and their Conversion into Chiral Pyridinium
Salts in Water Pp. 396-398
Gustavo H.R. Vianna, Itamar C. dos Santos, Rossimiriam
P. de Freitas, Laurent Gil and Rosemeire B. Alves
[Abstract]
Microwave-Assisted Solid Phase Synthesis of GLP-1-Analogues
Pp. 399-402
Yushi Chi, Huibin Zhang, Jinpei Zhou, Wenlong Huang and
Shuaijian Ni
[Abstract]
Electrophilic Substitution Reaction of Indole:
Part XXII—Synthesis
of a Novel Spiro Heterocyclic System Pp. 403-406
Anupam Nayak, Asima Chatterjee, Julie Banerji, Munmun
Saha, Sukumar Manna, Sanchayita Kanrar and Tomoyasu Hirose
[Abstract]
Abstracts
[Back to top]
Synthesis of 1-Aminocyclopropyl-Pentanoic and -Heptanoic Acid
Derivatives
Martina Gensini, Laura Quartara and Maria Altamura
Herein we report the synthesis of new (1-amino-cyclopropyl)-pentanoic
and -heptanoic acid derivatives by titanium-mediated reductive
cyclopropanation of the correspondent amides.
[Back to top]
Phenol and Naphthol Oxidation to Quinones with Hydrogen Peroxide
Using Vanadium-Substituted Keggin Heteropoly Acid as Catalyst
Gustavo P. Romanelli, Paula I. Villabrille, Patricia G.
Vázquez, Cármen V. Cáceres and Pietro
Tundo
Phenols and naphthols were oxidized to the corresponding
quinones using 60% p/V hydrogen peroxide and a substituted
vanadium Keggin heteropolyacid (H4 PMo11
VO40.12H2
O, HPA) as catalyst. The reactions were carried out at room
temperature using acetone as solvent. This procedure was a
mild and effective alternative for the phenol oxidation to
quinones in good yields.
[Back to top]
Design and Synthesis of Novel Thioether-linked Carbapenem-
Oxazolidinone Hybrids as Potential Antimicrobial Agents
Jianwei Wang, Juan Huang, Yong Wu, Li Hai and Guangming
Wang
Discovery of novel antimicrobial agents effective against
infections caused by drug-resistant pathogens is an important
objective in drug research field. In order to find new structural
classes of antibiotics, a series of novel thioether-linked
carbapenem-oxazolidinone hybrids were synthesized. The structures
of the hybrids and intermediates were confirmed by 1H
NMR, IR, MS and elemental analysis.
[Back to top]
Enantioselective Michael Addition of Nitroolefins and Cyclohexanones
Catalyzed by Novel Pyrrolidine-thiourea Bifunctional Catalysts
with Two Chiral Centers
Dongping Cheng and Weiliang Bao
Catalyzed by the novel pyrrolidine-thiourea bifunctional
catalysts with two chiral centers, the asymmetric Michael
addition of nitroolefins and cyclohexanones was successfully
performed. A wide range of the products were obtained in good
to excellent enantioselectivies and diastereoselectivities.
[Back to top]
Palladium-Catalyzed Asymmetric Allylic Substitution Using
Phosphoramidite Ligands Bearing 1,1'-Binaphthyl Skeleton
Yongguang Gao, Xinsheng Li, Weiyi Chen and Dongcheng Xu
A series of chiral phosphoramidite ligands with 1,1'-binaphthyl
skeleton have been used in palladium-catalyzed asymmetric
allylic alkylation of 1,3-diphenylallyl acetate, which afford
substituted products in excellent yields (up to 100 %) and
good enantiometric excesses (up to 83 % ee).
[Back to top]
Microwave-Assisted Synthesis of 1,3-Thiazolidin-4-ones and
2-Aryl-1,3-oxathiolan-5-ones
Wilson Cunico, Walcimar T. Vellasco Junior, Marcele Moreth
and Claudia R.B. Gomes
A microwave-enhanced, rapid, three-component one-pot
condensation method has been developed for the synthesis of
1,3-thiazolidin-4-ones using toluene in open vessels at atmospheric
pressure. Applying this methodology, eleven 1,3-oxathiolan-5-ones
were also synthesized in good yields.
[Back to top]
Iodine/EtOH: A Novel and Versatile Catalyst for the Synthesis
of β-Amino
Ketones via Three Component Reaction
Jhillu S. Yadav, Basi V.S. Reddy, Kattela S. Shankar,
Kokku Premalatha and Tallapally Swamy
A variety of β-amino
ketones are readily prepared in high yields and with good
to excellent anti selectivity under extremely mild
conditions by means of three component coupling of aromatic
aldehydes, aryl amines and ketones using 10 mol% of molecular
iodine in ethanol. The use of readily available iodine makes
this process quite simple, more convenient and cost-effective.
[Back to top]
Synthesis of Sugar β-Amino
Acid Containing Homooligomeric Cyclic Peptides
Manuel Andreini, Claude Taillefumier, Brigitte Fernette
and Yves Chapleur
The synthesis of new cyclic peptides built from D-mannose-derived
"anomeric" β
3.3 -aminoacids has been carried out using a
solution-phase coupling methodology. Tetramers and hexamers
in which the peptide backbone includes the anomeric carbon
of the sugar are obtained and show perfect symmetry by nmr
clearly indicating the occurrence of rapid interchanging conformers
in solution. The lowest energy conformers obtained by molecular
modelling suggest a bowl shape for the peptide backbone in
which intramolecular hydrogen bonds between NH and CO of the
amide group but also unusual hydrogen bonds involving the
sugar ring oxygen could exist.
[Back to top]
The Facile and Efficient Three-Component One-Pot Mannich-Type
Reaction of Indoles Catalyzed by In(OTf)3
Under Microwave
Irradiations
Dipak Prajapati, Sunil Gadhwal and Rupam Sarma
Indium triflate catalysed the three-component one-pot
reaction of indole 1 with a heteroimine generated
in situ under microwave irradiations and afforded
predominately secondary indolyl amines 4
in excellent yields as well as bisindolyl methane 5
in poor yields. The catalyst indium triflate can be recovered
after the reaction and reused in the subsequent experiments.
[Back to top]
Ultrasound Assisted Selective Reduction of Chalcones to Dihydrochalcones
by Zn/HOAc
Liang Zhang, Weige Zhang, Xin Wang, Kai Bao, Guodong Lu
and Jinshun Lin
An efficient ultrasound assisted method has been developed
for the chemoselective synthesis of dihydrochalcones from
chalcones using Zn/HOAc as a reductive system. Under the reaction
conditions, isolated double bonds, benzyloxy groups and aromatic
halides are found to remain unaffected.
[Back to top]
A New 6H-Pyran-3-one Scaffold Derived from a C-Glycoside Supporting
Information i-xvii
Natalia de la Figuera, Sandra Fiol, Joan C. Fernández,
Pilar Forns, Dolors Fernández-Forner and Fernando Albericio
A new monosaccharide-based scaffold has been designed
and synthesized. The scaffold can be used to build compound
libraries for HTS against carbohydrate-processing enzymes
and related therapeutic targets.
Undesired pyrane ring-opening of the 2,3-unsaturated intermediate
during reduction with LiALH4
is described.
[Back to top]
Morita-Baylis-Hillman Reaction in Water/Ionic Liquids under
Microwave Irradiation
Rodrigo O.M.A. de Souza, Andréa L.F. de Souza,
Tatiana L. Fernández,Aires C. Silva, Vera L.P. Pereira,
Pierre M. Esteves,Mario L.A.A. Vasconcellos and Octavio A.C.
Antunes
The present work describes a new experimental protocol
of the Morita-Baylis-Hillman reaction in H2O
/ Ionic Liquid media under microwave irradiation. Different
proportions of ionic liquids, ([bmim][PF6]
and [bmim][BF4]), and water
were tested as solvents for the reaction between several aromatic
aldehydes and Michael acceptors under microwave irradiation.
The results show that small amounts of ionic liquid, mixed
in water, can shorter reaction times keeping good yields.
[Back to top]
Efficient Synthesis of Aza-Phenanthroindolizidine and Aza-Phenanthro-quinolizidine
and Anticancer Activities
Kailiang Wang, Wenlong Wang, Qingmin Wang and Runqiu Huang
Aza-modifications of phenanthroindolizidine and phenanthroquinolizidine
alkaloids were firstly designed to produce two aza-analogues,13a-azatylophorine
and 14a-aza-7 methoxylcryptopleurine starting from
hydrazine monohydrate with high overall yields, respectively.
The synthesis highlighted that some kinds of reactions were
ameliorated in methodology. The newly synthesized target molecules
including their salt derivatives were evaluated for anticancer
activities against the BEL-7402 human liver cancer cell line
and MOLT-4 human leukemia cell line. They exhibit anticancer
activities.
[Back to top]
Enantioselective Synthesis of 2, 6-Disubstituted Dihydropyrone
Derivatives Catalyzed by TiCl4
/ BINOL/RONa System
Yuan-Cong Zhao, Ji Zhang, Na Wang, Hong Yu, Xin-Bing
Yang, Shan-Yong Chen and Xiao-Qi Yu
A facile method for the preparation of chiral pyrone
derivatives through hetero-Diels-Alder reaction is described.
Sodium alcoholates were used as efficient additives in the
enantioselective reactions catalyzed by MCl4
(M = Ti4+
Sn4+) / (R)-BINOL
systems. The optically resulted active 2, 6-disubsituted dihydropyrones
could be obtained with up to 94% ees and 88% yields.
[Back to top]
Rapid Microwave-Promoted Solvent-Free Synthesis of Zincke’s
Salts and their Conversion into Chiral Pyridinium Salts in
Water
Gustavo H.R. Vianna, Itamar C. dos Santos, Rossimiriam
P. de Freitas,
Laurent Gil and Rosemeire B. Alves
Solvent-free synthesis of Zincke’s salts followed
by their conversion into chiral pyrinium salts in aqueous
media is presented.
[Back to top]
Microwave-Assisted Solid Phase Synthesis of GLP-1-Analogues
Yushi Chi, Huibin Zhang, Jinpei Zhou, Wenlong Huang and
Shuaijian Ni
Gly8-GLP-1 (7~36) amide
and Exendin- 4, analogues of Glucagon-like peptide-1 (GLP-1),
were synthesized rapidly and efficiently on rink amide MBHA
resin under microwave irradiation, using Fmoc/tBu orthogonal
protection strategy. The results showed that the synthesis
of the medium-to large-length peptides was greatly improved
in the reaction time and the purity of crude product with
the use of microwave irradiation.
[Back to top]
Electrophilic Substitution Reaction of Indole: Part XXII—Synthesis
of a Novel Spiro Heterocyclic System
Anupam Nayak, Asima Chatterjee, Julie Banerji, Munmun
Saha, Sukumar Manna, Sanchayita Kanrar and Tomoyasu Hirose
The reaction of indole with acetone in the presence of
mineral/Lewis acid continues to be a fascinating area for
investigation since 1913, specially due to the instability
of the indolyl ca rbinol being generated in situ.
We report here the synthesis of a novel spiro heterocyclic
system obtained during the study of this reaction using BF3.
Et2O. |
