Letters in Organic Chemistry, Volume 2, No. 6, 2005
Contents
Modification of Nucleoside Heterocycles to Probe and
Expand Nucleic Acid Structure and Function Pp.496-500
Eriks
Rozners
Letters in Organic Chemistry
2-Imidazolone Derivatives Obtained as Unexpected
Products Throughout Imidazole N3-Oxide Rearrangement
(Supplementary Material Available)
H.
Cerecetto, A. Gerpe, M. Gonzalez, O.E. Piro and E.E. Castellano
An Effective Methodology to Novel Larger Imidazolium
Cyclophanes Pp.507-511
Xia
Wei, Jin Liu, Guo-lin Zhang, Zong-lin Jiang, Cheng-he Zhou, Kui Luo and Ru-gang
Xie
Diastereoselective Allylation of Imines with g–Silyloxyallylstannanes Promoted by
Trimethylsilyl Triflate and Application to the Synthesis of Erythro-Sphingosine
Pp.512-514
Makoto
Shimizu, Hiromi Ando and Yasuki Niwa
Introduction of a Benzoquinone Pharmacophore on a
Labdane Platform Pp.515-517
Jamila
Aslaoui and Christophe Morin
Fluorine-Substituted Tetraphenylethene Systems
Pp.518-520
Zakir
Hussain, Henning Hopf and Thomas Oeser
Efficient Chemical Synthesis of Sialic Acid Related
Oligosaccharides Pp.521-523
C.
Zhao, X. Zhen, H. Zhang and Y. Ding
Enantioselective Nozaki-Hiyama Allylations Using a
Multidentate Amino Alcohol as a Chiral Ligand Pp.524-527
Eriks
Rozners and Juan Fontanez
Synthesis of 14-Membered Ring Jaspamide Derivatives
Pp.528-531
Sylvain
Celanire, Carole Descamps-François, Brigitte Lesur, Gerald Guillaumet and
Benoît Joseph
First Microwave-Assisted Synthesis of 3-Substituted
Isocoumarins Pp.532-534
Khalid
Mohammed Khan, Sumbul Ahmed, Zulfiqar Ali Khan, Mubeen Rani, Shahnaz Perveen,
M. Iqbal Choudhary and Atta-ur-Rahman
Syntheses of Carbamate Derivatives of Quercetin by
Reaction with Amino Acid Ester Isocyanates Pp.535-538
Xianxue
Wu, Li Cheng, Dong Xiang and Yuquan Wei
A Combined Theoretical and Experimental Approach to
2,3,2',3' Tetrahydro- 1H,1'H-[2,2']Biindenyl Pp.539-543
Zakir
Hussain, Henning Hopf , Thomas
Oeser and Joerg Grunenberg
Chromium Trioxide Supported on NaHSO4.H2O:
Simple Oxidation of Alcohols in Solution and Solvent free Conditions
Pp.544-546
Farhad
Shirini, Mohammad Ali Zolfigol and Shayesteh Torabi
An Enantiomeric Synthesis of (+)-Gloeosporone
Pp.547-549
Anubha
Sharma, Sunita Gamre and Subrata Chattopadhyay
Phosphonium Ionic Liquids as Solvents for Nitration
Reactions of Arenes Pp.550-553
Bethany
D. Powell, Gregory L. Powell and Perry C. Reeves
Efficient Photocleavage of Lysozyme by a New Chiral
Probe Pp.554-558
Apinya
Buranaprapuk, Parin Chaivisuthangkura, Jisnuson Svasti and Challa V. Kumar
Oxidation of Aromatic Alcohols to Carbonyl Compounds
with Oxygen Catalyzed by Iron (III) Chloride Supported on Kieselguhr
Pp.559-560
Mohammed
M. Hashmi, Ali Ezabadi and Zahed Karimi-Jaberi
One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones
Using ZnCl2, CuCl2, NiCl2 and CoCl2
Doped Hydroxyapatite Pp.561-565
Hanane
El Badaoui, Fathallaah Bazi, Samira Sokori, Saïd Boulaajaj, Hassan B. Lazrek
and Said Sebti
Functionalized, Differently Fluorinated Building-Blocks
Via Michael Addition of Enamines to g-Fluoro-a-Nitroalkenes
Pp.566-568
A Facile Method for the Synthesis of Pyrazolyl and Pyrazolinyl
Carbazoles Pp.569-572
Yusuf
Zulykama, Rajagopal Nagarajan and Paramasivan T. Perumal
Abstracts
[Back to top] Modification of Nucleoside Heterocycles to Probe and
Expand Nucleic Acid Structure and Function
Eriks Rozners
Recent progress in molecular biology and genetics has invigorated interest in modified nucleic acids both for fundamental studies and for practical applications. Herein, recent advances in design of modified non-Watson-Crick base pairs are highlighted. Examples of altered hydrogen-bonding patterns, size-expanded bases, and base pairing dependent on metal chelation and hydrophobic interactions are discussed.
[Back to top] 2-Imidazolone Derivatives Obtained as Unexpected Products
Throughout Imidazole N3-Oxide Rearrangement (Supplementary Material
Available)
3-Alkyl(aryl)-2,3-dihydro-1H-2-imidazolone derivatives as unexpected product of the reaction between ethyl 3-alkyl(aryl)amino-2-oximinobutanoate and methyl orthoformate is described. These imidazolones are generated by an intramolecular attack and a migration of N3-oxide oxygen from the imidazole N3-oxide intermediates. This proposed mechanism is supported by the results of theoretical studies (DFT).
[Back to top] An Effective Methodology to Novel Larger Imidazolium
Cyclophanes
Xia
Wei, Jin Liu, Guo-lin Zhang, Zong-lin Jiang, Cheng-he Zhou, Kui Luo and Ru-gang
Xie
A type of novel larger imidazolium cyclophanes have been designed and synthesized by ingeniously employing intermediates with spacers. The tandem-MS has been employed to certify that the cyclophanes unarguably have symmetrical structures like calix[8]arene.
[Back to top] Diastereoselective Allylation of Imines with g–Silyloxyallylstannanes Promoted by
Trimethylsilyl Triflate and Application to the Synthesis of Erythro-Sphingosine
Makoto
Shimizu, Hiromi Ando and Yasuki Niwa
Addition of g-silyloxyallylstannanes to imines in the presence of trimethylsilyl triflate was studied. Allylation of a-imino ester with (Z)-allylstannane proceeded to give anti-adduct as a major product, which was transformed into N,O,O-triacetyl erythro-sphingposine via appropriate functional group transformations.
[Back to top] Introduction of a Benzoquinone Pharmacophore on a Labdane
Platform
Jamila Aslaoui and Christophe Morin
The allylic alcohol of the side-chain of larixol was converted into an exo 1,3-diene through trifluoroacetylation followed by palladium-catalyzed elimination; this allowed the introduction of a benzoquinone pharmacophore on this labdane platform in ‘one-pot’ from allylic trifluoroacetates.
[Back to top] Fluorine-Substituted Tetraphenylethene Systems
Zakir Hussain, Henning Hopf and Thomas Oeser
Synthesis of novel fluorinated tetraphenylethene systems 5a-c was carried out and resulting new materials were investigated for their mesomorphic properties. New materials (5a-c) were prepared by the esterification of 3 with either 4-trifluoromethoxybenzoic acid (5a), 3,4,5-trifluorobenzoic acid (5b), or 4-trifluoromethylbenzoic acid (5c). All compounds (5a-c) were fully characterized while stereochemical features of compound 5a were investigated by its single crystal X-ray analysis.
[Back to top] Efficient Chemical Synthesis of Sialic Acid Related Oligosaccharides
C. Zhao, X. Zhen, H. Zhang and Y. Ding
A very efficient strategy for the chemical synthesis of the sialyl Lewis X tetrasaccharide is reported. Starting from four simple monosaccharide building blocks, sialyl Lewis X was obtained in seven steps. By using similar strategy, sialyl LacNAc and sulfated sialyl LacNAc trisaccharides were also synthesized.
[Back to top] Enantioselective Nozaki-Hiyama Allylations Using a
Multidentate Amino Alcohol as a Chiral Ligand
Eriks Rozners and Juan Fontanez
Asymmetric Nozaki-Hiyama allylations using a proline derived amino alcohol as a chiral ligand showed good enantioselectivity (er up to 90:10). The results suggest that efficient catalysts for this type of chromium-mediated reactions may be designed using multidentate ligands based on sp3 hybridized backbones.
[Back to top] Synthesis of 14-Membered Ring Jaspamide Derivatives
Sylvain Celanire, Carole Descamps-Francois, Brigitte Lesur, Gerald Guillaumet and Benoit Joseph
Two synthetic approaches of simpler jaspamide derivatives were investigated. The ring closure step was attempted either by RCM or by macrolactonisation. 14-Membered ring derivatives 15-16 were prepared by final macrolactonisation using Yamaguchi reagent.
[Back to top] First Microwave-Assisted Synthesis of 3-Substituted
Isocoumarins
Khalid Mohammed Khan, Sumbul Ahmed, Zulfiqar Ali Khan, Mubeen Rani, Shahnaz Perveen, M. Iqbal Choudhary and Atta-ur-Rahman
A microwave-assisted, environment friendly, high yielding, time saving synthesis of medicinally important 3-substituted isocoumarins was carried out in a single step by the direct condensation of homophthalic acid with aryol and acyl chlorides under the solvent-free conditions without any solid support. The synthesized isocoumarins were structurally characterized by microanalysis, 1H-NMR, EI, IR and UV.
[Back to top] Syntheses of Carbamate Derivatives of Quercetin by
Reaction with Amino Acid Ester Isocyanates
Xianxue Wu, Li Cheng, Dong Xiang and Yuquan Wei
Synthesis of amino acid carbamate derivatives of quercetin from partly protected quercetin and amino acid esters utilizing triphosgene as an auxiliary reagent was studied. A series of quercetin derivatives were obtained regioselectively by reaction with amino acid ester isocyanates under mild conditions and in high yields.
[Back to top] A Combined Theoretical and Experimental Approach to
2,3,2',3' Tetrahydro- 1H,1'H-[2,2']Biindenyl
Zakir
Hussain, Henning Hopf , Thomas
Oeser and Joerg Grunenberg
Synthesis of 2,3,2',3'-tetrahydro-1H,1'H-[2,2']biindenyl 2 from the dimerization reaction of indene with lithium naphthalenide was carried out and we here report its single crystal X-ray structure. Synthesis and characterization of compounds 3-8 have also been carried out successfully. The stability of biindenyl and its stereochemistry at position 2 and 2' was investigated using density functional theory.
[Back to top] Chromium Trioxide Supported on NaHSO4.H2O:
Simple Oxidation of Alcohols in Solution and Solvent free Conditions
Farhad Shirini, Mohammad Ali Zolfigol and Shayesteh Torabi
Alcohols are conveniently converted to their corresponding carbonyl compounds with CrO3 supported on NaHSO4.H2O in solution and under solvent free conditions.
[Back to top] An Enantiomeric Synthesis of (+)-Gloeosporone
Anubha
Sharma, Sunita Gamre and Subrata Chattopadhyay
A simple and facile synthesis of (+)-gloeosporone was developed using chirons that were available by lipase catalyzed acylation and chemical resolution.
[Back to top] Phosphonium Ionic Liquids as Solvents for Nitration
Reactions of Arenes
Bethany
D. Powell, Gregory L. Powell and Perry C. Reeves
Commercially available tetraalkylphosphonium ionic liquids are effective as solvents in the mild nitration of various arenes and offer some advantages over the more common N, N-dialkylimidazolium ionic liquids.
[Back to top] Efficient Photocleavage of Lysozyme by a New Chiral Probe
Apinya
Buranaprapuk, Parin Chaivisuthangkura, Jisnuson Svasti and Challa V. Kumar
Photocleavage of lysozyme and bovine serum albumin (BSA) by L-phenylalanine-1(1-pyrene)methylamide (PMA-L-Phe) is reported here. The chiral probe, PMA-L-Phe, has a positively charged side chain, while the previous probes carried a free carboxyl group. The yield of lysozyme cleavage by PMA-L-Phe is increased to 57% when compared to the previous probes, while the yield of BSA cleavage is reduced to <5%. Sequencing studies indicated that PMA-L-Phe cleaves lysozyme at a single site, between residues Trp108-Val109. Absorption and fluorescence spectral data indicate that PMA-L-Phe binds to lysozyme and BSA with affinity constants (Kb) of 3.3x105 M-1 and 3.8x105 M-1, respectively.
[Back to top] Oxidation of Aromatic Alcohols to Carbonyl Compounds with
Oxygen Catalyzed by Iron (III) Chloride Supported on Kieselguhr
Mohammed
M. Hashmi, Ali Ezabadi and Zahed Karimi-Jaberi
Oxidation of aromatic alcohols to corresponding aldehydes and ketones have been carried out using molecular oxygen and FeCl3 supported on kieselguhr as catalyst in good yields.
[Back to top] One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones
Using ZnCl2, CuCl2, NiCl2 and CoCl2
Doped Hydroxyapatite
Hanane El Badaoui, Fathallaah Bazi, Samira Sokori, Saïd Boulaajaj, Hassan B. Lazrek and Said Sebti
Hydroxyapatite doped with ZnCl2, CuCl2, NiCl2 and CoCl2 efficiently catalyses the three components Biginelli reaction between an aldehyde, ethyl acetoacetate and urea in refluxing toluene to afford the corresponding dihydropyrimidinones in high yields.
[Back to top] Functionalized, Differently Fluorinated Building-Blocks Via
Michael Addition of Enamines to g-Fluoro-a-Nitroalkenes
Marco Molteni and Matteo Zanda
The Michael addition of ketone-derived enamines to g-fluoro-a-nitroalkenes provides in moderate to good isolated yields the corresponding b-fluoroalkyl g-nitroketones, which can be reduced to b-fluoroalkyl g-nitroalcohols.
[Back to top] A Facile Method for the Synthesis of Pyrazolyl and
Pyrazolinyl Carbazoles
Yusuf Zulykama, Rajagopal Nagarajan and Paramasivan T. Perumal
Synthesis of pyrazolylcarbazoles and pyrazolinylcarbazoles is reported. Phenylhydrazones of acylcarbazoles furnished pyrazolylcarbazoles under Vilsmeier conditions. Carbazolylchalcones on treatment with hydrazine in acetic acid furnished pyrazolinylcarbazoles.