Letters in Organic Chemistry

ISSN: 1570-1786

Letters in Organic Chemistry
Volume 2, Number 8, December 2005

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Highlights in Organic Chemistry

Metal Trifluoromethanesulfonates as Versatile Catalysts in Carbohydrate Synthesis

Suvarn S. Kulkarni & Shang-Cheng Hung Some recent advances of metal trifluoromethanesulfonates as efficient catalysts in carbohydrate synthesis are descibed, with special emphasis on protection and glycosylation.

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Recent Advances in Cascade Enyne/RCM in Organic Synthesis

Krishna P. Kaliappan A concise highlight on recent advances in cascade/enyne RCM reactions of a range of substrates is discussed. Some of the reported strategies led to total synthesis of biologically active natural products.

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Letters in Organic Chemistry

Polymerization of L-Aspartic Acid to Polysuccinimide and Copoly(Succinimide-Aspartate) in Supercritical Carbon Dioxide

Kenneth M. Doll, Randal L. Shogren, Ronald A. Holser, J. L. Willett & Graham Swift We have synthesized polysuccinimide and a similar compound, copoly(succinimide-aspartate), in a reaction using supercritical carbon dioxide as a solvent. This avoids the use of environmentally harmful organic solvent yet facilitates the reaction.

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Synthesis of α-Amino-ω-Hydroxy-Polyethylene Glycol Oligodeoxyribonucleotide Conjugates

Boris K. Chernov, Darrell P. Chandler & Julia B. Golova α-(Fmoc-amino)-polyethylene glycol-(2-cyanoethyl-N,N-diisopropyl)-phosphoramidite was synthesized from PEG- 900 and used for preparation of oligonucleotide conjugates by means of automatic solid phase synthesis.

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Synthesis of Novel Coumarin Derivatives 7,8-Fused onto Thiazole

Stéphane Frère, Valérie Thiéry & Thierry Besson Original thiazolocoumarins have been synthesized under microwave irradiation from corresponding imino-1,2,3-dithiazoles besides cyanoimidoylchlorides and isothiocyanates.

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Total Synthesis of Lyngbyabellin A

Heungwing Pang, Zhengshuang Xu, Zhiyong Chen & Tao Ye The total synthesis of lyngbyabellin A, a biologically active metabolite from the marine cyanobacterium Lyngbya majuscula, is reported.

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The Total Synthesis of Pitipeptolide A

Yungui Peng, Heungwing Pang, Zhengshuang Xu & Tao Ye An efficient synthesis of the marine cyanobacterium metabolite pitipeptolide A is presented.

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Preparation of Azepinoindole Derivatives via Oxidative Palladium Couplings

Lionel Joucla, Cyril Montagne, Guy Fournet & Benoît Joseph Oxidative palladium couplings allow the preparation in high yields of different azepinoindole moieties. The use of CuCl2 as reoxidant leads to the formation of halogenated derivatives instead of alkenes.

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Solvothermal In Situ Ligand Synthesis, Crystal Structure and Fluorescent Properties of a New Heterocyclic Compound 1, 1 - Bis{3-(Pyridin-2-yl)H-Imidazo[1, 5-a]Pyridine}

Cai-Ming Liu, Hong-Yun Gao, De-Qing Zhang & Dao-Ben Zhu A novel crystalline fluorescent compound 1, 1¢-bis{3-(pyridin-2-yl)H-imidazo[1, 5-a]pyridine} 1 was produced by in situ reaction of bis(2-pyridinylmethyl)amine (bpa) in the presence of Fe(ClO4)2 × 6H2O and NaN3 under solvothermal conditions, while the iron(II) complex Fe(bpa)2(ClO4)2 2 was obtained as byproduct.

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Solvent-Free Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones Using Trichloroisocyanuric Acids

Farhad Shirini, Mohammad A. Zolfigol & Esmail Mollarazi An efficient method for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) using trichloroisocyanuric acid (TCICA) under solvent-free conditions is reported.

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The Use of Enantiomerically Pure α,β-Unsaturated N-Acyloxazolidin-2-One in Diastereoselective Baylis-Hillman Type Reaction Mediated by SmI2

Manouchehr Mamaghani, Mohammad Reza Yazdanbakhsh, Abed Badrian, Hassan Valizadeh & Heshmat Allah Samimi The reaction of (R)-3-(2-bromo-3-phenyl-acryloyl)-5,5-dimethyl-4-phenyl-oxazolidin-2-one 3 with aliphatic aldehydes in the presence of SmI2 provides Baylis-Hillman adducts under mild reaction conditions and with short reaction times (<10 min.).

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A New and Convenient Method of Generating Alkyl Cyanides from Alcohols and Thiols Using 2,4,6-Trichloro[1,3,5]Triazine/n-Bu4NCN

Batool Akhlaghinia & Elham Roohi Alkyl cyanides are prepared in good to excellent yields ( average yield 93% )by treatment of alcohols and thiols with 2,4,6 trichloro[1,3,5]triazine/n-Bu4NCN in refluxing acetonitrile. This method is highly selective for conversion of 1° alcohols in the presence of 2° and 3° ones and thiols.

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Electrogenerated Cyanomethyl Anion in Organic Synthesis. Synthesis of 1,3-Oxazolidine-2,4-Diones

Leucio Rossi, Marta Feroci, Mirella Verdecchia & Achille Inesi Cyanomethyl anion, generated by cathodic reduction of MeCN Et4NClO4 solution is used in combination with gaseous CO2 as an alternative carboxylating reagent for the synthesis of oxazolidine-2,4-diones starting from halo amides under safe and mild conditions. Reaction yields were moderate to very good (43-90%).

A Simple and Efficient Method for Synthesis of Isocyanurates Catalyzed by Potassium Phthalimide Under Solvent-Free Conditions

Firouz Matloubi Moghaddam, Mohammad G. Dekamin & Gholam R. Koozehgari Potassium phthalimide and succinimide catalyzed cyclotrimerization of isocyanates under solvent-free conditions.

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Facile Regioselective Synthesis of Pyrrolo-Pyrones: Tandem Reaction of 4-N-(4 -Aryloxy-2 -ynyl), N-Methyl Pyran-2-Ones with 3 Chloroperoxybenzoic Acid

Krishna C. Majumdar, Habibur Rahaman & Brindaban Roy A convenient route to the synthesis of potentially bioactive fused pyrrolo- pyrones by amine oxide rearrangement in excellent yield under a very mild condition.

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An Efficient, One-Pot, Basic Resin Catalyzed Novel Synthesis of Carbamate Esters Through Alcoholic Tosylates

Devdutt Chaturvedi & Suprabhat Ray A convenient, efficient, one-pot, novel process has been developed for the synthesis of carbamates from corresponding amines and alcoholic tosylates using basic resin/CO2 system is described.

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Direct-Thiocyanation of Ketones Using Cerium (IV) Ammonium Nitrate

Atul Kumar & Seema R. Pathak An efficient and novel methodology for direct thiocyanation of enolisable ketones using cerium (IV) ammonium nitrate as oxidant and ammonium thiocyanate as thiocynating agent in the presence of 18 crown 6-ether.

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Synthesis of a Tetrasaccharide Present in Motif B of the Mycobacterium tuberculosis Cell Wall

Linsen Heng, Xiangdong Mei, Zhe Yao & Jun Ning α-D-Arabinofuranosyl-(1--5)-[α-D-arabinofuranosyl-(1--3)]-a-D-arabinofuranosyl-(1--5)-D-arabinofuranose (6) present in motif B of the Mycobacterium tuberculosis cell wall was regio- and stereospecifically synthesized by trichloroacetimidate method.

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(Salen)Ti(IV)-Catalyzed Asymmetric Ring-Opening of Monosubstituted Epoxides with Dithiophosphorus Acid

Zhenghong Zhou, Quanyong Wang, Bing Liu, Guofeng Zhao, Qilin Zhou & Chuchi Tang The asymmetric ring-opening of monosubstituted epoxides with dithiophosphorus acids catalyzed by a (salen)Ti(IV) complex formed in situ from the reaction of Ti(OPr-i)4 and the chiral salen ligand derived from (1R,2R)-(+)-diaminocyclohexane and (R)-2,2’-diamino-1,1’- binaphthalene was realized.

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Acid-Promoted Cleavage of 4,4-Bis(Alkylthio)But-3-en-2-One and Subsequent Thio-Michael Addition to α,β-Unsaturated Ketones

Haifeng Yu, Dewen Dong, Yan Ouyang, Qun Liu & Yan Wang 4,4-Bis(ethylthio)but-3-en-2-one and 4,4-bis(benzylthio)but-3-en-2-one have been investigated as non-thiolic and odorless thiol equivalents in thio-Michael addition. β-keto sulfides were prepared in good yields under mild acidic conditions.

Chromium Trioxide Supported on NaHSO4.H2O: Efficient Oxidative Deprotection of Trimethylsilyl Ethers in Solution and Under Solvent Free Conditions

Farhad Shirini, Mohammad Ali Zolfigol & Shayesteh Torabi Chromium trioxide supported on NaHSO4.H2O can be used as an efficient reagent for the conversion of trimethylsilyl ethers to their corresponding carbonyl compounds in solution and under solvent free conditions.

CeCl3.7H2O-SiO2: An Efficient and Reusable Catalyst for the Synthesis of β-Keto Enol Ethers

Gowravaram Sabitha, N. Mallikarjuna Reddy, K. Sudhakar & J.S. Yadav Cyclic β-diketones are converted into β-keto enol ethers in the presence of alcohols using a catalytic amount of Cerium(III) chloride heptahydrate adsorbed on silica gel (CeCl3.7H2O-SiO2) in good yields. The catalyst is reusable and can be applied several times.

Bromination of Thiophene in Micro Reactors

Patrick Löb, Volker Hessel, Heinrich Klefenz, Holger Löwe & Kyra Mazanek A significant improvement of yield and selectivity for the bromination of thiophene to 2,5-dibromo-thiophene is reported here utilizing a micro reactor rig in a solvent-free continuous bromination reaction. The use of a micro reactor also leads to a large decrease in reaction time and space-time yields which are an order of magnitude larger than in a comparable batch operation.

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