HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Special Issue
Yoshito Kishi's Special Issues, Vol. 72, No. 1, 2007
Published online: 23rd February, 2007
■ Ring-Mediated Transformations of Macrolide Antibiotics
Takushi Kaneko,* William McMillen, Meghan Keaney Lynch, and Jon Bordner
*Pfizer Global Research and Development, Eastern Point Road, Groton, CT 06340, U.S.A.
Abstract
Ketene acetal intermediate 5 was synthesized and shown to be a useful intermediate in the synthesis of macrolide antibiotics. Its synthesis and subsequent substitution reactions are controlled by the macrocyclic ring system and the juxtaposition of functional groups. The ring-mediated reactions provided unique 13- and 14-membered macrolide templates different from those available biosynthetically.
Published online: 27th October, 2006
■ Donor-π-Acceptor Type Symmetric Cyclic Triindoles: Synthesis and Properties
Hidetaka Hiyoshi,* Hironobu Kumagai, Hideo Ooi, Takaaki Sonoda, and Shuntaro Mataka
*Advanced Materials Department, Ihara Chemical Industry Co., Ltd., 2256, Nakanogo, Fujikawa-cho, Ihara-gun, Shizuoka 421-3306, Japan
Abstract
Donor-π-acceptor type symmetric cyclic triindole derivatives, 10,15-(2-ethylhexy)-2,7,12-triaryl-10,15-dihydro-5H-5,10,15-triazadiindeno-[1,2-a;1’,2’-c]fluorenes (3a-c) were prepared by the Suzuki-Miyaura cross-coupling reaction of 5,10,15-(2-ethylhexy)-2,7,12-tribromo-10,15-dihydro-5H-5,10,15-triazadiindeno[1,2-a;1’,2’-c]fluorene (2c) which was obtained by cyclotrimerization reaction of N-(2-ethylhexyl)-5-bromoindolin-2-one in phosphoryl chloride. These triindole derivatives had reversible redox oxidation potentials (Eo) in cyclic voltammetry, and furthermore, showed photoluminescence due to an intramolecular charge transfer (ICT).
Published online: 2nd November, 2006
■ Synthesis of Designed Acylquinic Acid Derivatives Involved in Blue Color Development of Hydrangea and Their Co-pigmentation Effect
Yuki Toyama-Kato, Tadao Kondo, and Kumi Yoshida*
*Graduate School of Information Science, Nagoya University, Chikusa, Nagoya, Aichi 464-8601, Japan
Abstract
The blue sepal color of hydrangea may be developed by an unstable supramolecular metal-complex pigment composed of delphinidin 3-glucoside (1), 5-O-caffeoylquinic acid (2) and 5-O-p-coumaroylquinic acid (3) as co-pigments and Al3+ in aqueous solution. To clarify the structure of blue pigment and the role of co-pigments, various acylquinic acid derivatives were designed and synthesized. As a result of reproduction experiment using the synthesized co-pigments, it was revealed that 1-COOH, 1-OH and 5-O-ester of quinic acid moiety was essential for blue color development. The aromatic plane of the 5-O-acyl moiety contributes to the stability of the blue complex.
Published online: 17th November, 2006
■ Practical Racemic and Asymmetric Formal Total Syntheses of the Homocamptothecin Derivative and Anticancer Agent Diflomotecan via Tertiary Homoallylic Alcohols as Masked Aldol Equivalents
René Peters,* Christian Diolez, Alain Rolland, Eric Manginot, and Marc Veyrat
*Synthesis and Process Research, Safety & Technical Sciences, Pharmaceuticals Division, F.Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
Abstract
An efficient and scalable racemic as well as an asymmetric approach to the key building block for the synthesis of homocamptothecin and derivatives thereof such as the potent anticancer agent diflomotecan (4) are described. In the asymmetric route, the pyridone ring was assembled applying straightforward carbonyl chemistry. The selective generation of the quaternary stereocenter was accomplished by self reproduction of chiral information starting from (S)-2-hydroxybutyric acid (22) utilizing an allyl moiety to act as a masked carbonyl group. The optically pure DE building block (7) (er > 99.95 : 0.05) was obtained in 9.0% overall yield over 10 steps (two chromatographic purifications). The asymmetric “de novo pyridone approach” has the potential to serve as the basis for a technical synthesis of diflomotecan.
Published online: 28th November, 2006
■ Synthetic Studies on Chlorofusin: Synthesis of the Cyclic Peptide Portion
Tomonori Mori, Marie Miyagi, Kengo Suzuki, Mitsuhito Shibasaki, Yoko Saikawa, and Masaya Nakata*
*Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Hiyoshi, Kohoku-ku Yokohama 223-8522, Japan
Abstract
The cyclic peptide portion of chlorofusin was synthesized by condensation of the five segments, D-Ada-OTMSE, Boc-L-Orn(Cbz), Boc-L-Thr-L-Ala, L-Asn(Tr)-D-Asn(Tr)-D-Leu-OTMSE, and Boc-L-Thr-D-Leu, followed by cyclization at the amide bond between D-Ada and L-Orn.
Published online: 26th January, 2007
■ Synthesis of 2,4,5-Trisubstituted Thiazoles with a 5-(N,N-Dimethylaminomethyl) Substituent
Bernhard Stump, Philipp C. Kohler, W. Bernd Schweizer, and François Diederich*
*Laboratorium für Organische Chemie, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
Abstract
We report synthetic strategies to 2,4,5-trisubstituted thiazoles with a N,N-dimethylaminomethyl residue at C(5). Three different routes to build up these scaffolds are described. Furthermore, we report a retro-Brook rearrangement of a thiazole derivative as well as an unusual cyclization leading to a highly substituted benzothiazole.
Published online: 12th January, 2007
■ A Concise Route to Two Distinct E-Ring Structures of Ciguatoxins
Masayuki Inoue,* Masafumi Iwatsu, Shuji Yamashita, and Masahiro Hirama*
*Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan
Abstract
Ciguatoxins, the causative toxins of ciguatera seafood poisoning, are large ladder-like polycyclic ethers, and known to have more than 20 structurally distinct congeners. In this paper, we describe a new concise synthesis of the two E-ring structures, of different ring sizes, found in ciguatoxins. From the common oxepane intermediate, the seven-membered E-ring was prepared in three steps, and the eight-membered E-ring was synthesized in seven steps using ring expansion and olefin isomerization as key reactions.
Published online: 30th January, 2007
■ Synthetic Studies toward the Generation of Uridine-Amino Alcohol-Based Small Optimized Libraries
Michio Kurosu,* Prabagaran Narayanasamy, and Dean C. Crick
*Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, 1682 Campus Delivery, Fort Colllins, CO 80523-1682, U.S.A.
Abstract
An efficient synthesis of a versatile scaffold 3, anti-2-chloro-3-hydroxy ester can be achieved via a boron mediated diastereofacial anti-aldol reaction of 2-(N-methylbenzyl-N-2,4,6-trimethylbenzyl)-amino-1-phenylpropanol chloroester 1 and the uridyl aldehyde derivative 2. Generation of uridine-amino alcohol-based library is demonstrated by using the scaffold 3.
Published online: 12th January, 2007
■ Novel Highly Regioselective Syntheses of Unsymmetrical 2,3-Disubstituted Quinoxalines
Xu Hui, Fanny Schmidt, Mohammed Akram Fakhfakh, Xavier Franck, and Bruno Figadère*
*Laboratoire de Pharmacognosie, Faculte de Pharmacie, Université de Paris-Sud, 5, Rue Jean-Baptiste Clément, 92296 Châtenay-Malabry Cedex
Abstract
Non-symmetrical 2,3-disubstituted quinoxalines are not easily obtained in good yields because of the lack of regioselectivity of the Hinsberg condensation, or the large number of steps required for achieving their preparation. Two efficient methods leading to non-symmetrical 2,3-disubstituted quinoxalines, carried out in smooth conditions, have been developed in our laboratory. These methods enable the synthesis of pharmacologically active quinoxaline derivatives.
Published online: 12th January, 2007
■ Preparation of Biphenylene- and Benzocyclooctene-Fused Heterocycles
Hiroki Uoyama, Noboru Ono, and Hidemitsu Uno*
*Integrated Center for Science, Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan
Abstract
Nitration of biphenylene with bismuth subnitrate and thionyl chloride give a mixture of 2-nitrobiphenylene, 2-chloro-6-nitrobiphenylene, and 5-chloro-10-nitrobenzocyclooctene. Reactions of 2-nitrobiphenylene and 5-chloro-10-nitrobenzocyclooctene with ethyl isocyanoacetate in the presence of t-BuOK gave the corresponding pyrimidine N-oxide and pyrrole, respectively.
Published online: 19th January, 2007
■ Oxidative Cleavage Reaction of Substituted Indoles Catalyzed by Plant Cell Cultures
Masumi Takemoto,* Yasutaka Iwakiri, and Kiyoshi Tanaka
*School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan
Abstract
We have developed a novel method for the oxidative cleavage of indole carbon double bonds in the presence of H2O2 using plant cell cultures as peroxidase. The oxidative method has some advantage, as features such as mild reactions, good yields, easy work-up and safety.
Published online: 9th February, 2007
■ Formation of the C3-C4 Unsaturated Framework of Cribrostatin 4 via DEAD-Mediated Oxidation of an Allylic Tertiary Amine
Guillaume Vincent, Yuyin Chen, Jonathan W. Lane, and Robert M. Williams*
*Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, U.S.A.
Abstract
The formal synthesis of the tetrahydroisoquinoline alkaloid cribrostatin 4 (1) is described. The synthesis features as a key step a DEAD-mediated oxidation of an allylic tertiary amine to an iminium ion immediately followed by a Pictet-Spengler cyclization to form the pentacyclic skeleton of cribrostatin 4.
Published online: 19th December, 2006
■ Bicyclo[2.2.2]oct-7-ene Derivatives: A Green Preparation of the Fused Succinimide Ring
Jure Hren, Kristof Kranjc, Slovenko Polanc, and Marijan Kočevar*
*Department of Organic Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, P.O. Box 537, SI-1000 Ljubljana, Slovenia
Abstract
The reaction of differently substituted bicyclo[2.2.2]oct-7-ene-2exo,3exo,5exo,6exo-tetracarboxylic acid 2,3:5,6-dianhydrides (1a-g and 4) with various hydrazines was investigated. The starting 1a-g were transformed in an aqueous solution under microwave irradiation conditions to the corresponding fused N-aminosuccinimides with high yields. The derivative (4) also reacted at the additional carbonyl moiety to give 5a-c as the sole products.
Published online: 26th December, 2006
■ A New Route for Preparation of 2-Deoxy-D-ribofuranose Phospho Sugar
Tadashi Hanaya,* Hiroyuki Tsukui, Naomi Igi, Ayashi Noguchi, Heizan Kawamoto, and Hiroshi Yamamoto
*Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
The addition reaction of dimethyl phosphonate to (2R,4S)-4-(tert-butyldimethylsilyl)oxymethyl-2-methyl-1,3-dioxan-5-one (11a), followed by dehydroxylation, provided 1-O-(tert-butyldimethylsilyl)-3-deoxy-3-dimethoxyphosphinoyl-2,4-O-ethylidene-D-erythritol (13a). Elongation of carbon skeleton of the D-erythrose (14) derived from 13a and then acidic methanolysis gave a mixture of methyl 2,4-dideoxy-4-dimethoxyphosphinoyl-α,β-D-erythro-pentopyranosides (7), which was led to 2-deoxy-D-ribofuranose phospho sugar (4) in an appreciably improved total yield compared with the procedures via previously reported route.
Published online: 12th January, 2007
■ Short Synthesis of (+)-Cylindricine C and Formal Total Synthesis of (-)-Lepadiformine
Hisashi Mihara, Tomoyuki Shibuguchi, Akiyoshi Kuramochi, Takashi Ohshima, and Masakatsu Shibasaki*
*Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
Abstract
A short synthesis of (+)-cylindricine C (1c) and a formal total synthesis of (-)-lepadiformine (2) were achieved. The key strategy for the syntheses was a catalytic asymmetric Michael reaction using a two-center organocatalyst (11) (TaDiAS: Tartrate-derived Di-Ammonium Salt) and tandem cyclization to construct the tricyclic ring system.
Published online: 12th January, 2007
■ Synthesis of Chiral 2,6-Bis[1-(N-piperidinyl)ethyl]pyridines and Crystal Structures of Their Metal Complexes
Jun’ichi Uenishi* and Taro Takami
*Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan
Abstract
(R,R)- and (S,S)-2,6-bis[1-(N-cycloamino)ethyl]pyridines (3) were prepared from (S,S)- and (R,R)-pyridine-2,6-bis(1-hydroxyethyl) dimethane sulfonates (2) stereospecifically. Pd, Cu, and Zn complexes with 3 were synthesized, and their crystal structures were determined by X-ray analysis.
Published online: 12th January, 2007
■ Stereo Differenciated Synthesis of Optically Pure 2-[1-(1-Phenylethylamino)ethyl]-6-[1-(N-piperidinyl)ethyl]pyridines
Jun’ichi Uenishi,* Taro Takami, and Sachiko Aburatani
*Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan
Abstract
All eight stereoisomers of the title pyridines were synthesized. Stereospecific substitution reactions of 1-(2-pyridinyl)ethanol unit with piperidine and optically pure (R)- and (S)-1-phenethylamines were performed via tosylates or mesylates.
Published online: 16th January, 2007
■ Synthesis of Aryl Conjugated (1-Azaazulenyl)acetylenes and Facile Synthesis of Thiophene Fused 1-Azaazulenes
Noritaka Abe,* Yohei Harada, Yukiko Imachi, Hiroyuki Fujii, Akikazu Kakehi, and Motoo Shiro
*Department of Chemistry, Faculty of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan
Abstract
3-Ethynyl-1-azaazulene derivatives were obtained by Sonogashira-Hagihara reaction of 3-iodo-2-chloro-1-azaazulenes, and 2-(phenylethynyl)-1-azaazulenes were obtained by the reaction of 2-bromo-1-azaazulenes. Glaser reaction of 2-chloro-3-ethynyl-1-azaazulenes gave 1,4-bis(2-chloro-1-azaazulen-3-yl)-1,3-butadiyne. Treatment of 2-chloro-3-ethynyl-1-azaazulene derivatives with sodium hydrosulfide gave corresponding 1-thia-9-azacyclopent[a]azulene derivatives in good yield.
Published online: 19th January, 2007
■ NMR Detection of Intramolecular OH/OH Hydrogen Bond Networks: An Approach Using Isotopic Perturbation and Hydrogen Bond Mediated OH···OH J-Coupling
Carolyn E. Anderson, Alexander J. Pickrell, Sarah L. Sperry, Thomas E. Vasquez, Jr., Thomas G. Custer, Matthew B. Fierman, Daniel C. Lazar, Zachary W. Brown, Wendy S. Iskenderian, Daniel D. Hickstein, and Daniel J. O’Leary*
*Department of Chemistry, Pomona College, 645 North College Avenue, Claremont, CA 91711, U.S.A.
Abstract
A series of conformationally restricted triol and tetrol systems containing intramolecular hydrogen bond arrays has been prepared and characterized by X-ray crystallography and NMR spectroscopy. NMR isotopic perturbation measurements in DMSO-d6 and CD2Cl2 reveal that this methodology can be used to detect the spatial proximity of up to four contiguous hydroxyl groups sharing a 1,3-, 1,4-, or 1,5- relationship. Furthermore, hydrogen bond mediated scalar couplings can be used to assign the identity of NMR resonances arising from perturbed OH signals. Our studies suggest that isotope shifts in OH···OH networks are additive. An application in the area of natural product structure elucidation is presented.
Published online: 23rd January, 2007
■ Further Studies on a Samarium Diiodide-Promoted Reductive Carbon-Nitrogen Bond Cleavage Reaction: Synthesis of (+)-Aphanorphine
Miho Katoh, Hiroshi Inoue, and Toshio Honda*
*Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
Abstract
Samarium diiodide-promoted carbon-nitrogen bond cleavage reaction was applied to the 1,2,3,4-tetrahydroisoquinoline derivatives bearing an ester group at the 1- or 3-position to give the corresponding benzazepinones. Synthesis of (+)-aphanorphine was established by utilizing this reaction, as a key step.
Published online: 26th January, 2007
■ The Stereochemistry of Electrolysis and Samarium Diiodide-Induced Cyclization between Carbonyl and Enone System in Inter- and Intramolecular Coupling
Masakazu Sono,* Tsutomu Shoji, Tatsuya Tamaki, Satoko Kishi, and Motoo Tori
*Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihamabouji, Yamashiro-machi, Tokushima, 770-8514, Japan
Abstract
Both the inter- and intramolecular cyclization of the carbonyl compounds with α,β-unsaturated carbonyl system using samarium diiodide and electrolysis were carried out. The stereochemistry of the products was compared each other.
Published online: 23rd January, 2007
■ Alkyl- and Arylation of Oxacyclic Ethers with Triethylsilyl Triflate—2,4,6-Collidine—Gilman Reagent Combination: Remarkable Discrimination of Two Ether Oxygens
Hiromichi Fujioka,* Takuya Ohnaka, Takashi Okitsu, Ozora Kubo, Kazuhisa Okamoto, Yoshinari Sawama, and Yasuyuki Kita*
*Graduate School of Pharmaceutical Science, Osaka University, 1-6 Yamadaoka, Suita, Osaka 560-0871, Japan
Abstract
The alkylation reaction of oxacyclic ethers such as THP-ethers, THF-ethers, etc., has been developed. The treatment of oxacyclic ether with TESOTf and 2,4,6-collidine gives the collidinium salt intermediate obtained by the reaction of the cyclic oxygen atom. The addition of Gilman reagent to the mixture gives the alkylated product. The reaction proceeds with high chemoselectivity though there are two different oxygen atoms in the oxacyclic ethers.
Published online: 21st February, 2007
■ Formation of Phosphonylated Thiiranes in the Reaction of a Diazomethanephosphonate and Cycloaliphatic Thioketones
Grzegorz Mloston,* Katarzyna Urbaniak, Stanislaw Lesniak,* Piotr Wasiak, and Heinz Heimgartner*
*Institute of Organic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
Abstract
The reaction of diethyl diazomethanephosphonate (1) with cycloaliphatic thioketones (6) in THF at room temperature leads to the corresponding thiirane-2-phosphonates (7) in good yield. A reaction mechanism via 1,3-dipolar cycloaddition of the diazo compound with the C=S group to give the 2,5-dihydro-1,3,4-thiadiazole-2-phosphonate as an intermediate, which spontaneously eliminates nitrogen is most likely. The resulting thiocarbonyl ylide undergoes a 1,3-dipolar electrocyclization to yield a thiirane. These products can be desulfurized smoothly by treatment with tris(diethylamino)phosphine to give α,β-unsaturated phosphonates.
Published online: 19th January, 2007
■ Efficient Synthesis of Substituted 3-Amino-3,4-dihydropyran-2-ones
Diastereo and Enantioselective Tandem Michael Addition and Lactonization between α,β-Unsaturated Ketones and Glycine-Derived Silyl Enolates Using a Chiral Quaternary Ammonium Phenoxide
Hitoshi Nagao, Yoshinobu Yamane, and Teruaki Mukaiyama*
*Center for Basic Research, The Kitasato Institute, 6-15-5 (TCI), Toshima, Kita-ku, Tokyo 114-0003, Japan
Abstract
Chiral quaternary ammonium phenoxides are readily prepared from commercially available cinchona alkaloids and are employed as useful new asymmetric organocatalysts. The cinchonidine-derived catalyst is highly effective on Michael addition and successive lactonization between glycine-derived silyl enolates and α,β-unsaturated ketones. According to this asymmetric reaction, the corresponding 3-amino-3,4-dihydropyran-2-ones are formed in high yields with complete diastereoselectivities and excellent enantioselectivities.
Published online: 30th January, 2007
■ Amphidinolactone A, a New 13-Membered Macrolide from Dinoflagellate Amphidinium sp.
Yohei Takahashi, Takaaki Kubota, 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 13-membered macrolide, amphidinolactone A (1), has been isolated from a marine dinoflagellate Amphidinium sp., and the structure and relative stereochemistry were elucidated by spectroscopic data. Amphidinolactone A (1) is the first macrolide without a branched methyl or an exomethylene among all the macrolides isolated from the dinoflagellates so far.
Published online: 30th January, 2007
■ Facile Synthesis and Evaluation of Antitumor and Antiviral Activities of [1,2,5]Thiadiazolo[3,4-d]pyrimidines (8-Thiapurines) and 4-β-D-Ribofuranosyl-[1,2,5]thiadiazolo[3,4-d]pyrimidines
Tomohisa Nagamatsu,* Rafiqul Islam, and Noriyuki Ashida
*Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
Synthesis of 5-amino-[1,2,5]thiadiazolo[3,4-d]pyrimidin-7(6H)-ones (8-thiaguanine) (4a-m), 7-amino-[1,2,5]thiadiazolo[3,4-d]pyrimidin-5(4H)-ones (8-thiaisoguanine) (6a-k), 5,7-diamino-[1,2,5]thiadiazolo[3,4-d]pyrimidines (8a-d) and some other thiadiazolopyrimidine derivatives were prepared by treating 6-amino-5-nitrosopyrimidine derivatives with sodium thiosulfate in aqueous acid media. 4-β-D-Ribofuranosyl-[1,2,5]thiadiazolo[3,4-d]pyrimidine-5,7(4H,6H)-dione (8-thiaxanthosine) (18) was also prepared by the reliable method. Moderate antitumor and antiviral activities of the synthesized compounds have been evaluated in vitro.
Published online: 6th February, 2007
■ Scandium-Catalyzed Ring-Opening Desymmetrization of meso-Epoxides
Chikako Ogawa, Naiwei Wang, Marine Boudou, Stéphane Azoulay, Kei Manabe, and Shu Kobayashi*
*Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
Abstract
In the presence of catalytic amounts of Sc(DS)3 and chiral bipyridine ligand 1, ring-opening desymmetrization of meso-epoxides with aromatic amines and indole derivatives proceeded smoothly in water without using any organic solvents to afford the corresponding adducts in high yields with high enatioselectivities. Interestingly, the Sc-caytalyzed reactions proceeded much faster in water than in dichloromethane.
Published online: 13th February, 2007
■ Synthetic Studies Directed toward Ergot Alkaloids, (±)-6,7-Secoagroclavine, (±)-Chanoclavine-I, (±)-Chanoclavine-II, and (±)-Agroclavine-I, by an Efficient and Common Synthetic Route
Fumio Yamada, Yoshihiko Makita, and Masanori Somei*
*Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
Abstract
Novel three synthetic routes to (±)-6,7-secoagroclavine were developed from either methyl 3-(3-formylindol-4-yl)acrylate, indole-4-carbaldehyde, or 4-iodoindole-3-carbaldehyde. The total syntheses of (±)-chanoclavine-I, (±)-chanoclavine–II, and (±)-agroclavine-I were accomplished as well from the synthetic intermediates involved in the synthesis of (±)-6,7-secoagroclavine, culminating in establishing an efficient and common synthetic method for ergot alkaloids.
Published online: 23rd February, 2007
■ Synthesis of the Trioxadispiroketal Domain of Spirastrellolide B
Ce Wang and Craig J. Forsyth*
*Department of Chemistry, The Ohio State University, 100 West 18th Avenue Columbus, Ohio 43210, U.S.A.
Abstract
Assembly of the trioxadispiroketal domain of the naturally occurring protein serine/threonine phosphatase inhibitor spirastrellolide B via a staged double intramolecular hetero-Michael addition is detailed.
Published online: 23rd February, 2007
■ Asymmetric Synthesis of All Stereoisomers of Isofagomine Using [2,3]-Wittig Rearrangement
Yukiko Mihara, Hidetomo Ojima, Tatsushi Imahori, Yuichi Yoshimura, Hidekazu Ouchi, and Hiroki Takahata*
*Faculty of Pharmaceutical Sciences, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
Abstract
The asymmetric synthesis of all stereoisomers of isofagomine from 5-hydroxymethyl-3-piperidene 6, which was prepared by [2,3]-Wittig rearrangement of O-alkylstannylmethyl compound 5 derived from readily available chiral 3-hydroxypiperidene 4, is described.