Letters in Organic Chemistry, Volume 2, No. 5, 2005
Contents
Focus in Organic Chemistry
Ultra-Remote Stereocontrol by Conformational Communication of Information along a Carbon Chain Pp.389-391
Interviewed:
J. Clayden
Interviewer:
K. Soai
Highlights in Organic Chemistry
Recent Breakthroughs in Enantioselective Brønsted Acid
and Brønsted Base Catalysis Pp.398-403
P.M.
Pihko
Letters in Organic Chemistry
A Facile Synthesis of Chiral Isocyanate-phenol and
Unsymmetrical Urea Derived from Tyrosines without Protecting Phenolic Hydroxyl
Groups Pp.404-406
A.
Nagai, B. Ochiai and T. Endo
Arylboronic Acid-Lead Tetraacetate-Copper Diacetate: A
One-Pot System for Copper-Catalyzed N-Arylation Under Neutral Conditions
Pp.407-409
K.
Shimi, G. Boyer, J.-P. Finet and J.-P. Galy
Gold-Catalyzed Coupling of Alkynes and Acyl Iminiums Pp.410-414
C.
Wei and C.-J. Li
Synthesis of Azlactones, Phenylpyruvic Acid and
1,2,4-Triazine Derivatives Under Microwave Irradiation Pp.415-418
E.S.H.El
Ashry, E.S. Ramadan, H.A. Hamid and M. Hagar
A Facile Synthesis for Novel Pyrimido[1,3,4]Triazepine Pp.419-423
M.
Kidwai, K. Singhal and R. Thakur
Solid-State Supramolecular Chemistry of Zn-Tetraphenylporphyrins
with 4,4´-Dipyridyl N,N´-Dioxide and Hexamethylenetetramine Pp.424-427
Q.
Zeng, J. Lu, S. Xu, D. Wu, C. Liu, Y. Li, C. Wang and C. Bai
Three Components Coupling Catalysed by Na2CaP2O7:
Synthesis of a-Amino
Phosphonates Under Solvent-Free Conditions at Room Temperature Pp.428-432
M.
Zahouily, A. Elmakssoudi, A. Mezdar, A. Rayadh, S. Sebti and H.B. Lazrek
Synthesis, Chiral Separation, Barrier to Rotation and
Absolute Configuration of N-(O- Functionalized-Aryl)-4-Alkyl-Thiazolin-2-One
and Thiazoline-2-Thione Atropisomers Pp.433-443
N.
Vanthuyne, F. Andreoli, S. Fernandez, M. Roman and C. Roussel
Organic Synthesis in Solid Media. Alumina Supported
Sodium Hydrogen Sulfate as an Effective and Reusable Catalyst for ‘One-Pot’
Synthesis of Amides from Ketones in Dry Media Under Microwave Irradiation Pp.444-446
M.
Gopalakrishnan, P. Sureshkumar, V. Kanagarajan and J. Thanusu
Synthesis and in Vitro Anti-Proliferative
Activity of Racemic Trifluoro-Casodex® (Bicalutamide) Pp.447-449
M.
Sani, F. Viani, M. Binda, N. Zaffaroni and M. Zanda
Tetrabutylammonium Hydrogensulphate Catalyzed Efficient
Synthesis of Glycosyl(aryl) Dihydropyrimidinones Pp.450-457
N.
Dwivedi, R.C. Mishra and R.P. Tripathi
Sulfamic Acid: An Efficient Catalyst for the
Diastereoselective, One-Pot Synthesis of Pyrano Benzopyrans, Furano Benzopyrans
and Ethoxy Benzopyrans Pp.458-460
R.S.
Kumar, R. Nagarajan, K. Vijay and P.T. Perumal
1,10-Epoxyhypocretenolides from the
Azorean Endemic Leontodon rigens (Asteraceae) Pp.461-464
C. Zidorn, E.-P. Ellmerer, G. Konwalinka,
K.-H. Ongania, R. Schwaha, R. Greil, K. Joehrer, N.B. Perry and H. Stuppner
Direct a-Iodination
of Ketones Induced by Aqueous Hydrogen Peroxide Pp.465-468
M.
Jereb, J. Iskra, M. Zupan and S. Stavber
Arsole Aromaticity Revisited Pp.469-474
M.P.
Johansson and J. Juselius
New Methodology to Prepare Polyfunctionalized
Cycloheptane Synthons, with Four Stereocenters, by Hydrolytic Cleavage of the
Oxygen Bridge in C1-functionalized 8-oxabicyclic [4+3]-cycloadducts Pp.475-479
A.M.
Montana, F. Garcia and C. Batalla
Introduction of a New Stereocenter on C1-Functionalized
8-Oxabicyclo[3.2.1] oct-6-en 3-ones by a Regio- and Stereoselective
Electrophilic Addition. Obtention of Polyfunctionalized Cycloheptanes with Five
Stereocenters Pp.480-484
A.M.
Montana, F. Garcia and C. Batalla
Sodium Hypochlorite/Montmorillonite K10: An Effective
Oxidant for the Oxidation of Thiols to Disulfides Pp.485-486
M.M.
Hashemi, A. Rahimi and Z. Karimi-Jaberi
Abstracts
[Back to top] Ultra-Remote Stereocontrol by Conformational
Communication of Information along a Carbon Chain
Interviewed:
J. Clayden
Interviewer: K. Soai
The abstract for this article is not available.
[Back to top] Recent Breakthroughs in Enantioselective Brønsted Acid and
Brønsted Base Catalysis
P.M.
Pihko
Recent advances in enantioselective catalysis with chiral Brønsted acids and Brønsted bases are reviewed. These catalysts are capable of highly enantioselective amination, aza-Henry, conjugate addition, Friedel-Crafts alkylation, Mannich, and Morita-Baylis-Hillman reactions.
[Back to top] A Facile Synthesis of Chiral Isocyanate-phenol and
Unsymmetrical Urea Derived from Tyrosines without Protecting Phenolic Hydroxyl
Groups
A.
Nagai, B. Ochiai and T. Endo
A facile method for synthesis and isolation of chiral isocyanate-phenols, obtained from the reactions of L-tyrosine and L-DOPA [L-3-(3,4-dihydroxyphenyl)alanine] derivatives with di-tert-butyltricarbonate (DBTC), is described. Reaction of the obtained isocyanate-phenol with n-butylamine gave the corresponding chiral unsymmetrical urea.
[Back to top] Arylboronic Acid-Lead Tetraacetate-Copper Diacetate: A
One-Pot System for Copper-Catalyzed N-Arylation Under Neutral Conditions
K.
Shimi, G. Boyer, J.-P. Finet and J.-P. Galy
The one-pot reaction of arylboronic acids with lead tetraacetate in chloroform followed by treatment with 3,4-dimethylaniline in the presence of catalytic copper diacetate gave the corresponding diarylamines under neutral conditions in good to high yields. The reaction proceeded with electron-rich as well as with electron-depleted arylboronic derivatives.
[Back to top] Gold-Catalyzed Coupling of Alkynes and Acyl Iminiums
C.
Wei and C.-J. Li
A gold-catalyzed direct addition of alkynes to active acyl iminium ion, which was generated in situ with an acid chloride, to afford a propargylamides in excellent yields.
[Back to top] Synthesis of Azlactones, Phenylpyruvic Acid and
1,2,4-Triazine Derivatives Under Microwave Irradiation
E.S.H.El
Ashry, E.S. Ramadan, H.A. Hamid and M. Hagar
Microwave (MW) irradiation has been used in each step for the transformation of acyl glycines 2 to 6-benzyl-3-thioxo-2,3,4,5-tetrahydro-1,2,4-triazin-5-one (7a), and its 4-phenyl derivatives 7b and 7c. The oxazolone 3a was also transformed to phenylpyruvic acid 5, whose thiosemicarbazone 6 can be cyclized to 7a under MW. Methylation of 7c gave the respective S- and / or N-methylated derivatives, 8 and 9, based on the reaction conditions.
[Back to top] A Facile Synthesis for Novel Pyrimido[1,3,4]Triazepine
M.
Kidwai, K. Singhal and R. Thakur
An efficient route to the synthesis of novel fused pyrimidotriazepine derivatives using inorganic solid supports under MWs is described herein. The methodology uses microwave as an alternative heating source, which eliminates the usage of solvent during the course of reaction. With this environmentally benign approach, the reaction time is brought down from hours to minutes along with the yield enhancement. In addition, the catalytic role of different inorganic supports is studied for this [2+5] condensation reaction and montmorillonite K-10 clay is found to be the best solid support in terms of catalyst as well as an energy transfer medium.
[Back to top] Solid-State Supramolecular Chemistry of
Zn-Tetraphenylporphyrins with 4,4´-Dipyridyl N,N´-Dioxide and Hexamethylenetetramine
Q.
Zeng, J. Lu, S. Xu, D. Wu, C. Liu, Y. Li, C. Wang and C. Bai
Two H-shaped supramolecular complexes (C44H28N4Zn)2.(C10H8N2O2).2(CH2ClCH2Cl)1,(C44H28N4Zn)2. (C6H12N4).(CH2ClCH2Cl)2 have been prepared and characterized by single-crystal X-ray diffraction.
[Back to top] Three Components Coupling Catalysed by Na2CaP2O7:
Synthesis of a-Amino
Phosphonates Under Solvent-Free Conditions at Room Temperature
M.
Zahouily, A. Elmakssoudi, A. Mezdar, A. Rayadh, S. Sebti and H.B. Lazrek
Synthetic phosphate Na2CaP2O7 has been utilized as an efficient catalyst for the three components coupling of carbonyl compounds, aromatic and aliphatic amines and dialkyl phosphite to produce a-amino phosphonates. The reaction was carried out under solvent-free conditions at room temperature. The by-product H2O formed during the reaction increases the catalytic activity of Na2CaP2O7.
[Back to top] Synthesis, Chiral Separation, Barrier to Rotation and
Absolute Configuration of N-(O- Functionalized-Aryl)-4-Alkyl-Thiazolin-2-One
and Thiazoline-2-Thione Atropisomers
N.
Vanthuyne, F. Andreoli, S. Fernandez, M. Roman and C. Roussel
The synthesis of N-(o-aryl)-4-alkyl-thiazolin-2-one atropisomers bearing hydroxy-, methoxy-, amino- or isothiocyanato- groups as ortho-substituent are described from their thiazoline-2-thione analogues. The enantiomers were obtained optically pure by semi-preparative chiral HPLC, their optical properties and absolute configurations were established. The barriers to rotation were determined and are discussed according to the nature of the substituents.
[Back to top] Organic Synthesis in Solid Media. Alumina Supported
Sodium Hydrogen Sulfate as an Effective and Reusable Catalyst for ‘One-Pot’
Synthesis of Amides from Ketones in Dry Media Under Microwave Irradiation
M.
Gopalakrishnan, P. Sureshkumar, V. Kanagarajan and J. Thanusu
A great variety of amides were effectively isolated in high yields from the reaction of ketones and hydroxylamine hydrochloride in the presence of alumina supported sodium hydrogen sulfate catalyst in dry media under microwave irradiation in solvent-free conditions. The major products were formed by the migration of the aryl group of the intermediate ketoximes during Beckmann rearrangement. The catalyst can be reused up to six times after simple washing with diethyl ether.
[Back to top] Synthesis and in Vitro Anti-Proliferative Activity
of Racemic Trifluoro-Casodex® (Bicalutamide)
M.
Sani, F. Viani, M. Binda, N. Zaffaroni and M. Zanda
The trifluoro analogue 1 of Casodex® was synthesized in racemic form, according to a strategy based on the use of trifluoropyruvate as a key starting material. This compound showed significant in vitro antiproliferative activity on the human prostate cancer cell line LNCaP.
[Back to top] Tetrabutylammonium Hydrogensulphate Catalyzed Efficient
Synthesis of Glycosyl(aryl) Dihydropyrimidinones
N.
Dwivedi, R.C. Mishra and R.P. Tripathi
An efficient synthesis of glycosyl dihydropyrimidinones using a three-component reaction of a b-keto ester, glycosyl aldehyde, urea (or thiourea) in the presence of tetrabutylammonium hydrogensulphate and diethylene glycol as eco-friendly solvent has been reported. The reaction has been extended to the synthesis of aryl dihydropyrimidinones also. The glycosyl dihydropyrimidinones were obtained in excellent yields in less time than the methods already reported.
[Back to top] Sulfamic Acid: An Efficient Catalyst for the
Diastereoselective, One-Pot Synthesis of Pyrano Benzopyrans, Furano Benzopyrans
and Ethoxy Benzopyrans
R.S.
Kumar, R. Nagarajan, K. Vijay and P.T. Perumal
Sulfamic acid catalyses the one-pot three components coupling of aldehydes, anilines and electron rich dienophiles such as dihydropyran, dihydrofuran and ethyl vinylether resulting in the formation of pyrano, furano and ethoxy benzopyrans.
[Back to top] 1,10-Epoxyhypocretenolides from the Azorean Endemic Leontodon
rigens (Asteraceae)
C.
Zidorn, E.-P. Ellmerer, G. Konwalinka, K.-H. Ongania, R. Schwaha, R. Greil, K.
Joehrer, N.B. Perry and H. Stuppner
A methanolic extract of Leontodon rigens (Dryander in Aiton) Paiva & Ormonde yielded 1,10-epoxy-14-hydroxyhypocretenolide-b-D-glucopyranoside and its 6'-O-p-hydroxyphenylacetyl derivative. These compounds represent the first epoxyguaian-12,5-olide derivatives. The structures were established by means of high resolution mass spectrometry and 1-D and 2-D NMR spectroscopy. The cytotoxicity of the isolated compounds was assessed using the MTT assay and their potential to induce apoptosis by employing the annexin V-PI assay.
[Back to top] Direct a-Iodination
of Ketones Induced by Aqueous Hydrogen Peroxide
M.
Jereb, J. Iskra, M. Zupan and S. Stavber
A mild and effective method was developed for direct a-iodofunctionalisation of ketones using elemental iodine activated by 30 % aqueous hydrogen peroxide in the presence of acidic catalyst.
[Back to top] Arsole Aromaticity Revisited
M.P.
Johansson and J. Juselius
Using quantum chemical methodology, we reinvestigate the aromaticity of the much debated arsole, using the newly developed gauge-including magnetically induced currents (GIMIC) method. GIMIC provides a quantitative measure of the induced ring current strength, showing arsole to be moderately aromatic. Comparison is made with pyrrole, phosphole, and cyclopentadiene.
[Back to top] New Methodology to Prepare Polyfunctionalized
Cycloheptane Synthons, with Four Stereocenters, by Hydrolytic Cleavage of the
Oxygen Bridge in C1-functionalized 8-oxabicyclic [4+3]-cycloadducts
A.M.
Montana, F. Garcia and C. Batalla
A new synthetic methodology to obtain polyfunctionalized cycloheptane synthons, with up to four stereocenters, is presented. Three key processes are involved in this methodology: first, the synthesis of C1- functionalized 8-oxabicyclo[3.2.1]oct-6-en-3-ones by a [4+3] cycloaddition reaction; second, the stereoselective reduction of the carbonyl group on C3 and third, the hydrolytic cleavage of the oxygen bridge of the cycloadducts. This synthetic methodology is versatile enough to allow the preparation of a wide variety of polypropionate synthetic building blocks.
[Back to top] Introduction of a New Stereocenter on C1-Functionalized
8-Oxabicyclo[3.2.1] oct-6-en 3-ones by a Regio- and Stereoselective
Electrophilic Addition. Obtention of Polyfunctionalized Cycloheptanes with Five
Stereocenters
A.M.
Montana, F. Garcia and C. Batalla
A methodology to obtain polyfunctionalized cycloheptane synthons, with five stereocenters, is presented. The precursors are C1-functionalized 8-oxabicyclo[3.2.1]oct-6-en-3-ones, obtained by a [4+3] cycloaddition reaction. The stereoselective reduction of the carbonyl group on C3 of these cycloadducts, followed by an electrophilic addition of organic acids on the C6-C7 double bond, under controlled conditions, allows the introduction of a new stereocenters on C6. The introduction of this new substituent on C6 takes place in a regio- and stereoselective way by a preferential exo attack on the oxabicyclic substrates. This synthetic methodology is versatile enough to allow the preparation of a wide variety of polypropionate building blocks, with applications to the synthesis of natural products with biological interest.
[Back to top] Sodium Hypochlorite/Montmorillonite K10: An Effective
Oxidant for the Oxidation of Thiols to Disulfides
M.M.
Hashemi, A. Rahimi and Z. Karimi-Jaberi
Sodium hypochlorite adsorbed on montmorillonite K10 is a useful oxidant for the oxidation of thiols to disulfides under the room temperature.