Letters in Organic Chemistry

ISSN: 1570-1786

Letters in Organic Chemistry
Volume 3, Number 6, June 2006

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Chiral Amino-Amides as Solution Phase and Immobilized Ligands for the Catalytic Asymmetric Alkylation of Aromatic Aldehydes Pp. 430-436

Giordano Lesma, Bruno Danieli, Daniele Passarella, Alessandro Sacchetti & Alessandra Silvani Novel solution free and polymer supported chiral amino-amide 9-keto-bispidines are investigated as ligands in the addition reaction of diethylzinc to aromatic aldehydes.

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Enantioselective Aldol Reactions Catalysed by N-Toluenesulfonyl-L proline Amide in Ionic Liquids Pp. 437-441

Mária Meciarová, štefan Toma, Albrecht Berkessel & Burkhard Koch Enantioselective aldol reaction of acetone with different aromatic aldehydes catalysed by N-toluenesulfonyl-L-proline amide were studied in ionic liquids.

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Comparison and Evaluation of Two Immobilisation Techniques for Task Specific Onium Salts (TSOS) in Mizoroki-Heck Cross Coupling Reactions Pp. 442-446

Christoph Brochwitz, Armin Feldhoff, Ulrich Kunz, Michel Vaultier & Andreas Kirschning A coating consisting of an ionic liquid was deposited on silica gel as well as on a new polyvinylimidazolium phase and treated with a task specific onium salt (TSOS). The activity and stability of both immobilised Pd-species were studied and compared in Mizoroki-Heck cross coupling reactions.

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Stereoselective Synthesis of C3-C10 and C13-C21 Fragments of Laulimalide Pp. 447-454

Sreenivas Punna, Rakesh, Anabathula Prabhakar, Gangavaram V.M. Sharma & Ajit Chand Kunwar Synthesis of the C3-C10 and C13-C21 segments, having seven asymmetric centers of the marine macrolide, (-)-laulimalide is reported. The requisite stereogenic centers were generated on the chirons by the application of asymmetric reactions.

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A Concise Total Synthesis of 7-Substituted Eudistomin Analogs Pp. 455-458

Zuozhong Peng, Ji Song, Wensheng Liao, Rujian Ma, Shu-Hui Chen, Ge Li & Ryoichi Ando We report herein an optimized practical synthesis of three novel 7-substituted eudistomin analogs (1-3). The total syntheses of these complex tetracyclic molecules were accomplished in 22 steps from the requisite 7-substituted indoles.

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An Efficient and Stereoselective Synthesis of 2-Deoxy Ketopyranoses from exo-Glycals Pp. 459-462

Agustin Ponzinibbio, Pedro A. Colinas, Albrecht Lieberknecht & Rodolfo D. Bravo 2-Deoxy ketopyranoses were prepared in very good yields and excellent stereoselectivity by a one-pot procedure involving the iodohydroxylation of exo-glycals and removal of the iodide group using sodium dithionite.

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A Simple Synthesis of Orthogonally Protected 2,5 Diaminocyclohexanecarboxylic Acids Pp. 463-467

Loránd Kiss, István Szatmári & Ferenc Fülöp Simple and efficient methods have been developed for the synthesis of orthogonally protected 2,5-diaminocyclohexanecarboxylic acid diastereomers via the stereocontrolled transformation of 2-benzyloxycarbonylamino-4-cyclohexenecarboxylic acid to its iodolactone or epoxide.

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Reduction of N-Methoxy-N-Methylamides to the Corresponding Amines with AlCl3/LiAlH4 Pp. 468-469

Maria Luisa Di Gioia, Antonella Leggio, Adolfo Le Pera, Angelo Liguori, Francesca Perri & Maria Caterina Viscomi Aromatic and aliphatic Weinreb amides are selectively converted into the corresponding N-methoxy-N-methylamines by treatment with lithium aluminium hydride in the presence of aluminium chloride.

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Intramolecular Carbolithiation of Aromatic N-Allyl-N-(2 Lithioallyl)Amines: Reinvestigation of the Mechanism and Synthesis of Functionalized Pyrrolidines Pp. 470-476

Roberto Sanz*, Mª Pilar Castroviejo, Delia Miguel & Francisco J. Fañanás Functionalized N-aryl substituted pyrrolidines or secondary N-pentenyl anilines have been prepared depending on the reaction conditions from N-(2-bromoallyl)anilines through an intramolecular carbolithiation reaction. Our proposed mechanism for this process has been revised.

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Reactivity of the Bioactive Aminodiol Subunit: Experimental and Theoretical DFT Study of the Reaction of Silyl Protected Anti-N-Boc-3-Amino-3-Phenyl-1,2-Propanediols with NaH Pp. 477-483

Abdelkrim Hamdach, Abdeslem Bentama, Salvador Gil, Elena Zaballos-García, Jose Sepúlveda-Arques & Ramon J. Zaragozá The reaction of the partially protected (TBDMS), anti-N-Boc-3-methylamino, or anti-N-Boc-3-amino-3-phenyl-1,2-propanediols 7a or 7b, with sodium hydride, yields the oxazolidinones 8 and the silyl migration oxazinones 9, with different ratios (8a:9a; 93:7 and 8b:9b 50:50). The results have been explained experimental and theoretically.

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Microwave-Promoted Facile and Rapid Solvent-Free Synthesis Procedure for the Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones and –Thiones Using ZrO2/SO42- as a Reusable Heterogeneous Catalyst Pp. 484-488

Mannathusamy Gopalakrishnan, Purushothaman Sureshkumar, Vijayakumar Kanagarajan, Jeyaraman Thanusu, Ramalingam Govindaraju & Muthuvel R. Ezhilarasi Three-component one-pot cyclocondensation reaction of b-dicarbonyl compounds and urea/thiourea with structurally diverse aromatic aldehydes for the synthesis of corresponding 3,4-dihydropyrimidin-2(1H)-ones and -thiones has been reported using sulfated zirconia (ZrO2/SO42-) solid superacid as an efficient reusable heterogeneous catalyst.

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Efficient Method for the Synthesis of Optically Pure Terminal Olefin Bearing Long Chain α-Amino Acids Pp. 489-491

Wei Miao, Lanqi Jia, Zhiliu Zhang, Jingchao Dong, Yifeng Shi, Rujian Ma, Suhan Tang, Shu-Hui Chen & Ge Li Chiral terminal olefin bearing long chain α-amino acids were prepared via the following three-step sequence starting from (S)-N-Boc-2-pyrrolidone-5-carboxylic acid: (1) opening of the gamma-lactam ring by an organometallic reagent, (2) keto reduction, and (3) ester hydrolysis.

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Methyl 2-Methoxycarbonyl-3-Phenylpropionate Derivatives: A New Type of Angiotensin Converting Enzyme Inhibitors Pp. 492-494

Xiao-Hua Cai, Bing Xie & Hui Guo Methyl 2-methoxycarbonyl-3-phenyl propionate derivatives were prepared, and their inhibitory activities for angiotensin converting enzyme (ACE) were evaluated. The inhibitiory activity of methyl 3-{4-[2-[N-(4 methylbenzylphenyl)methyl, N-methylamino]ethoxy]phenyl}-2-methoxy carbonyl pro-pionate (5b, IC50 = 0.0039 µM) and methyl 3-{4-[2-[N-bis(4 methoxyphenyl)methyl, N-methylamino]ethoxy]phenyl}-2 methoxycarbonylpropionate (5d, IC50 = 0.0027 µM) was higher than that of control drug captopril (IC50 = 0.0075 µM).

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