Special Issue

Pierre Potier's Special Issues, Vol. 64, No. 1, 2004

58 data found. 31 - 58 listedFirst Previous
Paper | Special issue | Vol 64, No. 1, 2004, pp.241-248
Published online: 17th August, 2004
DOI: 10.3987/COM-04-S(P)19
Preparation of 2’,3’-Oxorane-fused Carbocyclic Nucleosides Based on N-Substituted 2-Azabicyclo[2.2.1]hept-5-en-3-ones

Minoru Ishikura,* Kota Matsumoto, and Atsushi Murakami

*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan

Abstract

The epoxidation of N-substituted 2-azabicyclo[2.2.1]hept-5-en-3-ones (1) led to the exo-selective formation of epoxides (2), and the use of 2 for the preparation of 2’,3’-oxirane-fused carbocyclic nucleosides (10) was attempted.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.249-259
Published online: 19th October, 2004
DOI: 10.3987/COM-04-S(P)21
A Short Synthesis of (-)-Deoxoprosophylline

Angélique Jourdant and Jieping Zhu*

*Institut de Chimie des Substances Naturelles, C.N.R.S., 1 avenue de la Terrasse, Bat. 27, 91198 Gif sur Yvette, France

Abstract

Syntheses of (-)-deoxoprosophylline from chiral L-N,N-dibenzylserine (TBDMS) aldehyde is reported. A highly diastereoselective nucleophilic addition of Büchi’s Grignard reagent to chiral serinal followed by an intramolecular reductive amination of ω-oxo amino diol are two key steps of the present synthesis.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.261-275
Published online: 3rd September, 2004
DOI: 10.3987/COM-04-S(P)22
Synthesis of 2,3-Dihydrofuro[3,2-c]pyridine-3,4-dicarboxylic Acid, a Conformationally Constrained Analogue of the Subtype Selective NMDA Receptor Agonist Homoquinolinic Acid

Marcus Vinicius Nora de Souza, Zhaohua Yan, and Robert H. Dodd*

*Institut de Chimie des Substances Naturelles, Centre National de la Recherche Scientifique, Avenue de la Terrasse, Bat. 27, 91198 Gif-sur-Yvette Cedex, France

Abstract

4-Allyloxy- and 4-prop-2-ynyloxy-3-iodopicolinic acid derivatives, obtained by reaction of 4-chloro-2-iodopicolinanilides (11,14) with the sodium salts of allyl alcohol and propargyl alcohol, respectively, were subjected to tri-n-butyltin hydride/AIBN free radical cyclization conditions. While the propargylic compound (15) did not cyclize, the allylic compounds (8, 28) cyclized in the presence of diphenyl diselenide, TEMPO or oxygen as radical trapping agents to give the corresponding 2,3-dihydrofuro[3,2-c]pyridine-4-carboxylic acid derivatives substituted at C-3 by a phenylselenylmethyl (20), 2,2,6,6-tetramethylpiperidin-1-yloxymethyl (22) or hydroxymethyl group (29), respectively. The latter was oxidized to the 3-carboxylic acid using ruthenium chloride /sodium periodate and the C-4 benzyl ester was hydrogenolyzed to afford the title compound (5), a conformationally constrained analogue of the subtype selective NMDA receptor agonist, homoquinolinic acid.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.277-289
Published online: 22nd October, 2004
DOI: 10.3987/COM-04-S(P)24
Studies on the Condensation Products from N-Primary 1,2-Amino Alcohols and Formaldehyde

David J. Aitken,* Laure Besson, Françoise Fournier, Henri-Philippe Husson, Pascale Lemoine, Denis Lesage, Francine Libot, Pierre-Guy Martin, Christelle Mellin-Morlière, Valérie Monnier, Jean-Claude Tabet, and Bernard Viossat

*Department of Chemistry, SEESIB Laboratory, Clermont-Ferrand 2, University of Blaise Pascal, 24 avenue des Landais, 93117 Aubiere, France

Abstract

The products of the condensation reactions of twenty-six different 1,2-amino alcohols with excess aqueous formaldehyde were identified, with the help of a simple and effective analytical technique based on mass spectroscopy. With a few exceptions, which arise from steric or solubility effects, most amino alcohols form bis(oxazolidine)methane adducts preferentially.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.291-303
Published online: 3rd September, 2004
DOI: 10.3987/COM-04-S(P)25
Reactions of 3-Phenyl-8-triphenylphosphoimino-1-azaazulene with Aryl Isocyanate, Aryl Isothiocyanate, and Carbondisulfide

Kentaro Nagamatsu, Hiroyuki Fujii, Noritaka Abe,* and Akikazu Kakehi

*Department of Chemistry, Faculty of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan

Abstract

Reaction of 3-phenyl-8-triphenylphosphoimino-1-azaazulene (1) with some aryl isocyanates gave 2-arylimino-4-phenyl-2,2a-dihydro-1,2a-diazacyclopent[cd]azulenes (2) and 8-arylimino-1,8-dihydro-1-azaazulenes (3). Reaction of 1 with p-toluenesulfonyl isocyanate gave 2-imino-3-(p-methylphenyl)-4-phenyl-2,2a-dihydro-1,2a-diazacyclopent[cd]azulene as cyclization-rearrangement product. Reaction of phenyl isothiocyanate gave 2. Tautomerization of between 8-imino-1,8-dihydro-1-azaazulenes (3) and 8-amino-1-azaazulenes was discussed on the basis of X-Ray structure analysis and molecular orbital calculation.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.305-316
Published online: 3rd September, 2004
DOI: 10.3987/COM-04-S(P)27
Synthesis of Azulen-3-ylheterocyclic Using 2-(1-Methoxycarbonylazulen-3-yl)ethynyltriphenylphosphonium Bromide

Noboru Morita,* Shiro Moriyama, Taku Shoji, Masashi Nakashima, Masataka Watanabe, Shigeru Kikuchi, Shunji Ito, and Kunihide Fujimori

*Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan

Abstract

3-(3-methoxycarbonylazulen-1-yl)ethynyltriphenylphosphonium bromide was prepared from methyl 3-formylazulenecarboxylate. Its resonance structures were discussed on the basis of the 1H and 13C NMR spectroscopy. Furthermore, its reactivity with o-substituted aniline was examined. We found that 2-(1-methoxycarbonyl-azulen-3-yl)ethynyltri-phenylphosphonium bromide reacted with o-substituted aniline except 2-aminophenol to give corresponding methyl 3-(benzazol-2-yl)azulene-1-carboxylate.†

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Paper | Special issue | Vol 64, No. 1, 2004, pp.317-331
Published online: 5th October, 2004
DOI: 10.3987/COM-04-S(P)28
Alternative Access to Lactosamine-derived Oxazoline via 2-Ulose Oxime as a Key Intermediate

Eisuke Kaji,* Yumiko Osa, Naomi Shinohara, Chiho Yanagi, Masae Sekine, and Kakashi Nishino

*School of Pharmaceutical Sciences, Kitasato University, Shirokane, Minato-ku, Tokyo 108-8641, Japan

Abstract

Lactosamine-derived oxazoline was synthesized via 2-ulose oxime as a key intermediate, in which substituent effects of the acyloxyimino group were investigated. On reduction of the oxime to amino group, p-chlorobenzoyloxime provided a good gluco : manno selectivity of 13 : 1. N-Acetyllactosaminyl chloride derived therefrom was readily converted into the oxazoline by AgOTf-promoted cyclization with an 84% yield.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.333-345
Published online: 20th August, 2004
DOI: 10.3987/COM-04-S(P)30
Design and Synthesis of 16-Membered Hybrid Macrolide Having a Thiazole Side Chain on the Carbonolide Skeleton

Noriyuki Nakajima* and Makoto Ubukata

*Biotechnology Research Center, Toyama Prefectural University, 5180 Kurokawa, Kosugi, Toyama 939-0398

Abstract

Design and synthesis of a 16-membered hybrid macrolide, which contained a 16-membered carbonolide-type lactone framework with a thiazole sidechain, were described.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.347-355
Published online: 10th December, 2004
DOI: 10.3987/COM-04-S(P)32
Synthesis and Reactions of N-o-Anisylsulfonylmethyl- and N-o-sec-Butoxysulfonylmethylcarbodiimides with Aldehydes

Vishnu K. Tandon,* Kunwar A. Singh, Sanjay Rai, and Albert M. van Leusen

*Chemistry Department, Lucknow University, Lucknow 226007, India

Abstract

N-o-Anisylsulfonylmethyl- and N-o-sec-butoxysulfonylmethyl- carbodiimides (2) and (3) have been synthesized from the corresponding sulfinic acids by Mannich reaction. 2 and 3 are useful synthons in two step synthesis of 2-amino-1,3-oxazoles(4).

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Paper | Special issue | Vol 64, No. 1, 2004, pp.357-366
Published online: 19th October, 2004
DOI: 10.3987/COM-04-S(P)35
Optically Active Tropocoronands Having Amino Acid Residues in Linker Chains: Syntheses, Metal Coordination Properties, and Their Abilities as an Asymmetric Catalyst

Ohki Sato* and Akira Tanbo

*Department of Chemistry, Faculty of Science, Saitama University, Urawa, Saitama 338-8570, Japan

Abstract

Optically active tropocoronands (7) having L-amino acid moieties were synthesized by stepwise and one-pot reactions of tropolone derivatives with amino acid linker chains. The coordination styles of their Ni(Ö†) and Pd(Ö†) complexes and the abilities as an asymmetric catalyst were investigated.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.367-382
Published online: 19th November, 2004
DOI: 10.3987/COM-04-S(P)38
Schiff Base Formation between 5-Formyl-2’-deoxyuridine and Lysine ε-Amino Group at Monomer and Oligomer Levels

Atsushi Kittaka,* Chikafumi Horii, Hiromichi Tanaka, Tadashi Miyasaka, Kazuo T. Nakamura, Reiko Kuroda, and Toru Sugiyama*

*Faculty of Pharmaceutical Sciences, Teikyo University, 1091-1 Suarashi, Sagamiko-machi, Tsukui-gun, Kanagawa 199-0195, Japan

Abstract

Schiff base formation between the 5-formyl group of 5-formyl-2’-deoxyuridine, which is an oxidative thymidine lesion, and the ε-amino group of lysine at both monomer and oligomer levels is reported.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.383-391
Published online: 10th December, 2004
DOI: 10.3987/COM-04-S(P)39
New [2+2] and [4+4] Photodimerizations of 2-Pyridones in an Inclusion Complex with a Simple Carboxylic Acid Host: A Model of DNA Damage by Photodimerization of Its Thymine Component

Shinya Hirano, Shinji Toyota, and Fumio Toda*

*Department of Chemistry, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Okayama 700-0005, Japan

Abstract

A new [2+2] photodimerization of 5-chloro- and 5-methyl-2- pyridones to the corresponding cis-anti-dimer in an inclusion complex with 1,1’-biphenyl-2,2’-dicarboxylic acid was found. This reaction is a good model of thymine dimerization in a nucleotide which causes damage to DNA. A new [4+4] photodimerization of 5-chloro-2-pyridone to the cis-syn-dimer in the inclusion complex with 1,2,4,5-benzenetetracarboxylic acid was also found. The mechanism of these stereoselective photoreactions in the solid state was studied by X-Ray analysis.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.393-406
Published online: 9th November, 2004
DOI: 10.3987/COM-04-S(P)40
Synthesis of Orthogonally Protected Enantiopure 2,9-Diaminodecanedioic Acid: A Model for a New General Method for the Synthesis of Orthogonally Protected α,α’-Diaminodicarboxylic Acids

Cyrille Truchot and N. André Sasaki*

*Institut de Chimie des Substances Naturelles, C.N.R.S., 1 avenue de la Terrasse, Bat. 27, 91198 Gif sur Yvette, France

Abstract

A new method for the synthesis of orthogonally protected enantiopure α,α’-diaminodicarboxylic acids is described. A key step involves the Julia olefination of an aldehyde and a sulfone, both of which are derived from an optically pure dicarboxylic amino acid such as aspartic and glutamic acid. Straightforward synthesis of orthogonally protected 2,9-diaminodecanedioic acid is chosen to demonstrate the conciseness of this new versatile approach.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.407-416
Published online: 9th November, 2004
DOI: 10.3987/COM-04-S(P)42
Polymer-supported Phosphinooxathiane as Ligands for Palladium-catalyzed Asymmetric Allylations

Hiroto Nakano,* Kouichi Takahashi, and Reiko Fujita

*Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan

Abstract

New polymer-supported chiral ligands, PS-DES, PS-Et, and TentaGel supporting phosphinooxathianes were prepared and used in palladium-catalyzed asymmetric allylic alkylation and amination.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.417-435
Published online: 9th November, 2004
DOI: 10.3987/COM-04-S(P)43
Synthesis of Perhydropyrrolo[1,2-a]pyrazine-1,4-diones and Their Sulfur-Analogues by Ring-Enlargement of N-(2H-Azirin-3-yl)-L-prolinates

Artur Budzowski, Anthony Linden, and Heinz Heimgartner*

*Institute of Organic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland

Abstract

The hydrolysis of methyl N-(2,2-dimethyl-2H-azirin-3-yl)-L-prolinate (1c) at 50°C in the presence of silica gel afforded (S)-perhydro-3,3-dimethylpyrrolo[1,2-a]pyrazine-1,4-dione ((S)-4a), which was thionated chemoselectively to give the corresponding 1-thioxo derivative ((RS)-5a) as a racemic mixture. On the other hand, treatment of 1c with hydrogen sulfide led to the 4-thioxo isomer ((S)-6a). Thionation with Lawesson reagent yielded the bisthioxo compound ((RS)-7a), again as a racemate. Analogous reactions were carried out with the heterospirocyclic N-(2H-azirin-3-yl)-L-prolinates (1d) and (1e). The structures of (RS)-5a, (S)-6a-c, and (RS)-7a have been established by X-Ray crystallography.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.437-446
Published online: 3rd December, 2004
DOI: 10.3987/COM-04-S(P)47
Discovery and Synthesis of a Potent, Selective and Orally Bioavailble EP4 Receptor Agonist

Robert N. Young,* Xavier Billot, Yongxin Han, Deborah A. Slipetz, Nathalie Chauret, Michel Belley, Kathleen Metters, Marie-Claude Mathieu, Gillan M. Greig, Danielle Denis, and Mario Girard

*Department of Medicinal Chemistry, Merck Frosst Centre for Therapeutic Research, P.O. Box 1005, Pointe-Claire-Dorval, Quebec, H9R 4P8, Canada

Abstract

An optimized analog of prostaglandin E2 which incorporates a γ-lactam in place of the cyclopentanone ring and which incorporates metabolically stabilized side chains, has been identified and shown to exhibit potent and selective EP4 receptor agonism. The compound (2) (L-000902688) is also well absorbed on oral dosing and exhibits a long half-life making it an excellent tool for the study of the role of EP4 receptor in physiology and disease. An efficient synthesis of 2 from a chiral synthon is described.

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Paper | Special issue | Vol 64, No. 1, 2004, pp.447-461
Published online: 29th November, 2004
DOI: 10.3987/COM-04-S(P)48
A Facile Formation of Anti-Bredt’s Compounds from the Reaction of 1-Aroyl-2-aryl-3a,6a-diazapentalenes with Acetylenedicarboxylates

Hirokazu Iida, Hidehiro Uekusa, Yuji Ohashi, Hiroshi Hamana, Takahisa Machiguchi,* and Kiyoshi Matsumoto*

*Faculty of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences, 3 Shiomi-cho, Choshi, Chiba 288-0025, Japan

Abstract

The reaction of 1-aroyl-2-aryl-3a,6a-diazapentalenes with acetylene-di-carboxylates affords surprisingly unusual anti-Bredt’s adducts having 4,10-diazabicyclo-[5.2.1]-deca-1,3,5,8-tetraene structure. The structure was elucidated by making full uses of new MMR spectroscopies and finally an X-Ray crystallo-graphic analysis. The plausible mechanism for the formation of the present compounds is described.

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Note | Special issue | Vol 64, No. 1, 2004, pp.463-466
Published online: 27th April, 2004
DOI: 10.3987/COM-04-S(P)7
Intramolecular Pd-catalyzed Biaryl Coupling Reaction of N-Aryl-2-triflyloxybenzamides Using Pd(OAc)2, 1,3-Bis[diphenylphosphino]propane, Bu3P, and DBU

Hiromi Nishioka, Yoshimi Shoujiguchi, Hitoshi Abe, Yasuo Takeuchi, and Takashi Harayama*

*Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan

Abstract

Intramolecular Pd-catalyzed coupling reactions of N-aryl-2-triflyloxybenzamides were examined. The procedure using DBU as a base was effective for even in the reaction of oxygen-substituted benzamides.

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Note | Special issue | Vol 64, No. 1, 2004, pp.467-474
Published online: 30th July, 2004
DOI: 10.3987/COM-04-S(P)10
Organolanthanide Catalyzed Intramolecular 5-endo-dig Hydroamination: An Unusual Anti-Markovnikov Cyclization

Gary A. Molander* and Hikaru Hasegawa

*Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104-6323, U.S.A.

Abstract

Intramolecular 5-endo-dig hydroaminations of homopropargylamine derivatives were efficiently catalyzed by the organolanthanide precatalyst, Cp*2YbCH(TMS)2 (Cp* = C5Me5), to give the endocyclic enamine products. The 5-endo-dig hydroamination was also preferred in the presence of another olefin that would afford a 6-exo cyclization.

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Note | Special issue | Vol 64, No. 1, 2004, pp.475-482
Published online: 2nd November, 2004
DOI: 10.3987/COM-04-S(P)23
2-(o-Aminoaryl)indole Derivatives via the Coupling-Cyclization of o-Alkynylanilines with o-Halotrifluoroacetanilides in the Presence of a Palladium Catalyst

Antonio Arcadi, Sandro Cacchi,* Giancarlo Fabrizi, Fabio Marinelli, and Luca M. Parisi

*Department of Studies of Chemistry and Technology of Biologically Active Substances, University “La Sapienza”, P. le A. Moro 5, 00185 Rome, Italy

Abstract

The reaction of o-ethynylanilines with o-halotrifluoroacetanilides in the presence of PdCl2(PPh3)2 and Et3N in DMF at 90 °C affords 2-(o-trifluoroacetamidoaryl)indoles. The presence of the free amino group was found to play a crucial role in favoring the cyclization step.

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Note | Special issue | Vol 64, No. 1, 2004, pp.483-489
Published online: 22nd September, 2004
DOI: 10.3987/COM-04-S(P)29
Short Step Synthesis of an Antibiotic, 6-Cyano-5-methoxy-12-methylindolo[2,3-a]carbazole

Masanori Somei,* Fumio Yamada, Yoshiaki Suzuki, Shinobu Ohmoto, and Hiroyuki Hayashi

*Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan

Abstract

For evaluating the effectiveness of organic synthesis, both intellectual property factor (IPF) and application potential factor (APF) are proposed. As a representative example, a highly effective synthetic method with IPF value of 53.8 and APF value of 100 has been established starting from indigo directing toward an antibiotic, 6-cyano-5-methoxy-12-methylindolo[2,3-a]carbazole, using only conventional reagents without using any protecting groups.

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Note | Special issue | Vol 64, No. 1, 2004, pp.491-497
Published online: 21st September, 2004
DOI: 10.3987/COM-04-S(P)33
Combinatorial Chemical Synthesis of 4-Heteroaryl-3-substituted Pyrroles from Nitroalkenes

Clara Baldoli, Giuseppe Cremonesi, Piero Dalla Croce, Concetta La Rosa,* and Emanuela Licandro

*Dipartimento di Chimica Organica e Industriale, Centro C. N. R., Università degli Studi di Milano, V. Venezian 21, I-20133 Milano, Italy

Abstract

A small library of 4-(2-furyl)- or 4-(2-thienyl)-3-substituted pyrroles has been prepared by reaction of 2-(2-furyl or 2-thienyl)-1-nitro-1-alkenes (1) with secondary enamines (2). The reaction gives pyrrole derivatives by means of a Michael-type addition intermediate. Cyclization is influenced by the nature of the solvent and the substituent in the enamine β position, and by enamine-nitrogen nucleophilicity.

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Note | Special issue | Vol 64, No. 1, 2004, pp.499-504
Published online: 5th October, 2004
DOI: 10.3987/COM-04-S(P)34
Direct Synthesis of Heterobiaryls by Radical Addition to Pyridine: Epeditious Synthesis of Chelating Ligands

David Crich* and Mitesh Petel

*Department of Chemistry, University of Illinois at Chicago, 845 West Taylor St., Chicago, IL 60607-7061, U.S.A.

Abstract

The addition of aryl radicals to pyridine may be affected in moderate yield on exposure of aryl iodides to tributyltin hydride, AIBN, and diphenyl diselenide in hot pyridine. Mixtures of ortho-, meta-, and para-aryl substituted pyridines are typically obtained. When the iodide is ortho-substituted with a hydrogen bond donor, such as o-iodophenol, significantly improved selectivity for ortho-substituted pyridines, with potential as bidentate chelating ligands, is obtained.

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Note | Special issue | Vol 64, No. 1, 2004, pp.505-514
Published online: 12th November, 2004
DOI: 10.3987/COM-04-S(P)41
Asymmetric Synthesis of All Six Regioisomers of N-Boc-dimethylphenylalanines

Hidekazu Ouchi, Midori Kumagai, Shinobu Sakurada, and Hiroki Takahata*

*Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan

Abstract

All possible regioisomers of dimethyl-substituted (S)-phenylalanine were efficiently synthesized by reacting the Ni(II)-complex of the chiral Schiff base of glycine with (S)-2-N-(N-benzylprolyl)aminobenzophenone.

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Note | Special issue | Vol 64, No. 1, 2004, pp.515-521
Published online: 9th November, 2004
DOI: 10.3987/COM-04-S(P)44
Senepodine F, a New C22N2 Alkaloid from Lycopodium chinense

Yusuke Hirasawa, Hiroshi Morita, and Jun’ichi Kobayashi*

*Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812, Japan

Abstract

A new C22N2 Lycopodium alkaloid, senepodine F (1), consisting of a decahydroquinoline and a quinolizidine ring has been isolated together with senepodines A (2) and E (3) from the club moss Lycopodium chinense. The relative stereochemistry of 1 was determined by NOESY correlations for a deacetylated derivative.

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Review | Special issue | Vol 64, No. 1, 2004, pp.523-575
Published online: 17th September, 2004
DOI: 10.3987/REV-04-SR(P)1
Metabolites from Marine Sponges of the Genus Plakortis

Fredirik Rahm, Patricia Y. Hayes, and William Kitching*

*Department of Chemistry, The University of Queensland, St. Lucia, Brisbane, Queensland Q1d 4072, Australia

Abstract

Metabolites from the Plakortis genus of sponges are reviewed, with major focus on P. halichondrioides, P.simplex, P. angulospiculatus, P. lita, P. nigra, P. quasiamphiaster, P. zygompha, and the closely related Plakinastrella onkodes. The structures, stereochemistry, pharmacological activity and selected syntheses of these metabolites are discussed. Peroxy containing, polyketide derived metabolites constitute a prevalent class of biologically potent metabolites from Plakortis species.

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Review | Special issue | Vol 64, No. 1, 2004, pp.577-603
Published online: 7th September, 2004
DOI: 10.3987/REV-04-SR(P)2
2-Azabicyclo[2.2.0]hex-5-enes and 2-Azabicyclo[2.2.0]hexanes. A Review

Grant R. Krow* and Kevin C. Cannon

*Department of Chemistry, Temple University, Philadelphia, PA 19122, U.S.A.

Abstract

The synthesis and reactions of 2-azabicyclo[2.2.0]hex-5-enes and 2-azabicyclo[2.2.0]hexanes are reviewed.

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Review | Special issue | Vol 64, No. 1, 2004, pp.605-658
Published online: 26th October, 2004
DOI: 10.3987/REV-04-SR(P)3
β-Lactones as Intermediates for Natural Product Total Synthesis and New Transformations

Yingcai Wang, Reginald L. Tennyson, Daniel Romo*

*Department of Chemistry, Texas A & M University, College Station, Texas 77843-3255, U.S.A.

Abstract

The exploration of β-lactone reactivity and transformations has continued since the first synthesis of these strained heterocycles by Einhorn in 1883. The principal reactivity modes of β-lactones include nucleophilic addition resulting in either acyl C2-O1 or alkyl C4-O1 cleavage, rearrangement leading to ring expansion, decarboxylation, and electrophilic reactions of β-lactone enolates. Recent advances in asymmetric β-lactone synthesis has led to further developments in the area of novel transformations of β-lactones and significantly increased applications in natural product total synthesis. The latter topic is the focus of this review and covers the period inclusive to the end of 2003.

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