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
Victor Snieckus's Special Issues, Vol. 88, No. 1, 2014
Published online: 17th July, 2013
■ Synthesis and Molecular Structure of Cyclo[8](9,10-dihydro-9,10-anthraceno)pyrrole
Tetsuo Okujima,* Chie Ando, Shigeki Mori, Takahiro Nakae, Hiroko Yamada, and Hidemitsu Uno
*Department of Chemistry and Biology, Graduate School or Science and Engineering, Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan
Abstract
Cyclo[8]pyrrole with eight 9,10-dihydroanthracene wings was synthesized by oxidative coupling of the corresponding 2,2'-bipyrrole in good yield. The molecular structure was determined by single crystal X-ray analysis. The three-dimensionally structured cyclo[8]pyrrole possessed a cavity created by a pair of slip-stacked cyclo[8]pyrroles.
Published online: 2nd August, 2013
■ Synthesis of Tetrahydroquinolines through Intramolecular Carbolithiation Reactions
Oihane García-Calvo, Unai Martínez-Estíbalez, Esther Lete, and Nuria Sotomayor*
*Departamento de Química Orgánica, Facultad de Ciencia y Tecnologia, Universidad del País Vasco, Barrio Sarriena s/n. Leioa (Bizkaia) Bilbao 48940, Spain
Abstract
Cyclization of aryllithiums obtained by iodine-lithium exchange reaction on N-alkenyl 2-iodoanilines allows the synthesis of 4- and 2,4-substituted tetrahydroquinolines. However, the alkene has to be substituted with a stabilizing group for the resulting organolithium to favor the intramolecular carbolithiation. When (–)-sparteine (4) or (+)-sparteine surrogate (5) are used as chiral ligands low levels of enantioselection are obtained. The carbolithiation is completely diastereoselective when an enantiomerically pure precursor is used.
Published online: 23rd July, 2013
■ Highly Efficient, Enantiocontrolled Total Syntheses of (+)-Heliannuol D and (–)-Helibisabonol A
Yuki Manabe, Makoto Kanematsu, Mayu Osaka, Masahiro Yoshida, and Kozo Shishido*
*Graduate School of Pharmaceutical Sciences, University of Tokushima, 1-78-1 Sho-machi, Tokushima 770-8505, Japan
Abstract
Enantiocontrolled total syntheses of (+)-heliannuol D (1) and (−)-helibisabonol A (2) have been accomplished efficiently from a common intermediate 9, derived from the optically pure aryl allyl ether 7 via a chirality transfer through a Lewis acid-mediated Claisen rearrangement and asymmetric dihydroxylation.
Published online: 29th July, 2013
■ Study on Hinsberg Thiophene Synthesis of 4,8-Dihydro-4,8-ethanobenzo[1,2-c;4,5-c’]dithiophene
Kazunari Tagawa, Shigeki Mori, Takahiro Nakae, Tetsuo Okujima, and Hidemitsu Uno*
*Department of Chemistry and Biology, Graduate School or Science and Engineering, Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan
Abstract
The Hinsberg thiophene synthesis using 4,5,6,7-tetrahydro-4,7-ethanothiophene-5,6-dione and diethyl thiodiglycolate afforded a mixture of diethyl 4,8-dihydro-4,8-ethanobenzo[1,2-c;4,5-c’]dithiophene-1,3-dicarboxylate and its dihydrate, although the yields were low. The latter dihydrate was converted to the former dithiophene in a good yield by the treatment with Ac2O and DMAP.
Published online: 14th August, 2013
■ Synthesis of Novel Benzofuran Fused 1-Azaazulene Derivative by Tandem Intermolecular Suzuki Coupling/Intramolecular Buchwald-Hartwig Type Coupling
Hiroyuki Fujii,* Kazuya Sanada, Yu Kawai, Reiko Ikeda, Takeo Konakahara, and Noritaka Abe
*Department of Chemistry, Faculty of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan
Abstract
Synthesis of benzofuran fused 1-azaazulene derivative (cyclohepta[d]benzo[4,5]furano[2,3-b]pyrrole) (4) was achieved successfully by tandem intermolecular Suzuki coupling/intramolecular Buchwald-Hartwig type coupling of 2-chloro-3-iodo-1-azaazulene with 2-hydroxyphenylboronic acid pinacolate in the presence of Pd catalyst. The compound 4 was also obtained by the reaction of 2-chloro-1-azaazulene with 2-iodophenol in the presence of Pd catalyst in one pot. It was considered that the obtained tetra-cyclic heterocycles would consist 18π peripheral conjugated system by the studies of UV/Vis spectra and 1H NMR spectra, together with DFT calculation.
Published online: 23rd July, 2013
■ Enantioselective Synthesis of Spirooxindoles via Direct Catalytic Asymmetric Aldol-Type Reaction of Isothiocyanato Oxindoles
Shota Kato, Motomu Kanai, and Shigeki Matsunaga*
*Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
Abstract
Direct catalytic asymmetric aldol-type reaction of aldehydes with isothiocyanato oxindoles is described. A dinuclear (S)-Ni2-Schiff base complex (0.1-10 mol %) efficiently catalyzed the addition of isothiocyanato oxindoles to aliphatic aldehydes, giving spirooxindole products in 80-99% ee and 81:19-91:9 dr. A Sr(O-iPr)2/Schiff base complex (10 mol %) was utilized for aryl aldehydes and spirooxindole products were obtained in 33-78% ee and 96:4-98:2 dr.
Published online: 29th July, 2013
■ Synthesis of 4-Amino-, 4-Hydroxy-, and 4-Nitro-1,3,4,5-tetrahydrobenz[cd]indols and Its Bromination
Kyoko Nakagawa, Naokatsu Aoki, Harunobu Mukaiyama, and Masanori Somei*
*Noto Marine Laboratory, Institute of Nature and Environmental Technology, Faculty of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, 56-7 Matsuhidai, Matsudo-shi, Chiba 270-2214, Japan
Abstract
Simple synthetic method for 4-nitro-1,3,4,5-tetrahydrobenz[cd]indole (6) is established from indole-3-carboxaldehyde (7). With 6 in hand, various derivatives of 4-amino-, 4-hydroxy- and 4-amino-4-hydroxymethyl-1,3,4,5-tetrahydrobenz[cd]indoles become readily available. Bromination of 6 afforded useful building blocks for further manipulation. Successful optical resolution of 6 by chiral column chromatography is also reported.
Published online: 7th August, 2013
■ A Thermal Potential [6+4] 2H-Transfer Reaction in a Cyclic Dimer of Dimethyl 2a,8a-Dihydrocyclopent[c,d]azulene-1,2-dicarboxylate
Peter Uebelhart, Erja Lehto, and Hans-Jürgen Hansen*
*Institute of Organic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
Abstract
Azulenes and dimethyl acetylenedicarboxylate (ADM) react under catalysis of diethylaluminum chloride (Et2AlCl) in toluene to corresponding 2a,8a-dihydrocyclopenta[cd]azulene-1,2-dicarboxylates, which on further influence of Et2AlCl dimerize by bond formation between the central C(8b) and C(8’b) atoms and inter alia C(3) and C(8’) atoms. The thus formed heptacyclic compounds undergo on heating in tetralin an intramolecular disproportionation by transfer of two H-atoms from one to the other part of the heptacyclic structures. The kinetics of this process is studied with partially deuterated heptacycles.
Published online: 5th August, 2013
■ Potential DNA Bis-Intercalating Agents. Synthesis and Antitumor Activity of N,N'-(Methylenedi-4,1-cyclohexanediyl-bis(9-acridinamine) Isomers
Gordon W. Gribble,* Michael D. Mosher, Gary D. Jaycox, Michael Cory, and Terri A. Fairley
*6128 Burke Laboratory, Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, U.S.A.
Abstract
We describe the synthesis and antitumor activity of three novel isomeric bis-acridines 14-16 possessing a non-aromatic, semi-rigid dicyclohexylmethylene tether.
Published online: 30th July, 2013
■ Preparation and Spectroscopic Study of Alternate meta-Ethynylpyridine Oligomer Involving 2,4,6-Trisubstituted and 3,5-Disubstituted Pyridine Rings
Hajime Abe,* Daiki Suzuki, Ayako Shimizu, and Masahiko Inouye*
*Graduate School of Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, 930-0194, Japan
Abstract
A new type of ethynylpyridine cooligomer which consists of 3,5- and 2,6-pyridylene units alternately linked with acetylene bonds was prepared by repeating Sonogashira reaction. 1H NMR study suggested that this cooligomer associates with methanol by hydrogen-bonding at the pyridine units. Intramolecular excimer emission was observed around 540 nm by fluorescence measurement, indicating the formation of helical conformation. Weak induced CD was observed by the addition of octyl glucoside as a guest.
Published online: 30th July, 2013
■ Asymmetric Construction of Quaternary Stereogenic Centers via Auxiliary-Based SN2’ Reactions: A Case of 1,7-Relative Stereogenesis
Scott E. Denmark* and Lyndon K. Marble
*245 Roger Adams Laboratory Box 18-5 , Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, U.S.A.
Abstract
The stereoselective construction of quaternary stereogenic centers is described that employs an allylic substitution through the intermediacy of a chiral carbamate leaving group. Five carbamates with two substituents at the allylic terminus combined with phenylcopper or n-butylcopper to provide alkenes in moderate to good yields and with moderate to high enantioselectivities at the newly created quaternary stereogenic center. The E-carbamate with methyl and cyclohexyl substituents at the γ-terminus provided the highest yield (87%) and enantioselectivity (>99.9:0.1 er) of all the substitution patterns tested. The corresponding Z-carbamate gave the lowest enantioselectivity observed (80.0:20.0). Carbamates with other substituents (n-butyl and t-butyl) at the E-terminal position gave moderate yields and enantioselectivities of alkenes. Cinnamyl substrates also provided good yields of alkenes with moderate enantioselectivities. The origin of enantioselectivity is analyzed in the context of dimeric lithioheterocuprate structures.
Published online: 18th April, 2013
■ Aaptoline A, a New Quinoline Alkaloid from the Marine Sponge Aaptos suberitoides
Yodai Kudo, Hikaru Kato, Henki Rotinsulu, Fitje Losung, Remy E. P. Mangindaan, Nicole J. de Voogd, and Sachiko Tsukamoto*
*Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-hon-machi, Kumamoto 862-0973, Japan
Abstract
A new quinoline alkaloid, aaptoline A (1), was isolated from the marine sponge Aaptos suberitoides, along with known alkaloids, aaptamine (2), isoaaptamine (3), and demethylaaptamine (4). Interestingly, 1-4 are presumably biosynthesized from common precursors, L-DOPA and β-alanine aldehyde.
Published online: 30th May, 2013
■ Copper-Mediated Regioselective Homocoupling of Thiophenes and Indoles via Directed C–H Cleavage
Riko Odani, Mayuko Nishino, Koji Hirano,* Tetsuya Satoh, and Masahiro Miura*
*Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 560-0871, Japan
Abstract
We have developed a copper-mediated regioselective homocoupling reaction of thiophenes and indoles via functional-group-directed C–H cleavage to afford the corresponding bisthiophenes (bithiophenes) and bisindoles directly. The copper-based system can provide a concise and precious-metal-free access to the above heterocyclic cores of fundamental importance in material and pharmaceutical chemistry.
Published online: 11th June, 2013
■ Lewis Acid-Catalyzed Formylation Reaction of 4-(Piperazin-1-yl)phenols
Giuseppe Cremonesi, Piero Dalla Croce,* and Concetta La Rosa
*DISFARM - Section of General and Organic Chemistry "A. Marchesini", University of Milano, Via Venezian 21, I-20133 Milano, Italy
Abstract
The Lewis acid-catalyzed reaction of phenols 1 with paraformaldehyde in aprotic solvents affords good yields of salicylaldehydes 2.
Published online: 24th May, 2013
■ Two-Step Synthesis of 3,4-Ethylenedioxythiophene (EDOT) from 2,3-Butanedione
Iwao Hachiya, Toshihiro Yamamoto, Tatsuhiko Inagaki, Tomohiro Matsumoto, Atsushi Takahashi, Isao Mizota, and Makoto Shimizu*
*Department of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho Tsu, Mie 514-8507, Japan
Abstract
3,4-Ethylenedioxythiophene (EDOT) was synthesized from commercially available 2,3-butanedione in only a two-step procedure including ketalization and thiophene formation.
Published online: 13th June, 2013
■ Immobilisation of Phenanthroline-Bis Triazine (C1-BTPhen) on Magnetic Nanoparticles for Co-Extraction of Americium(III) and Europium(III)
Ashfaq Afsar, Dominic L. Laventine, Laurence M. Harwood,* Michael J. Hudson, and Andreas Geist
*Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, U.K.
Abstract
The present work reports a convenient route for the immobilisation of a phenanthroline-bis triazine (C1-BTPhen) group on the surface of zirconia-coated maghemite (γ-Fe2O3) magnetic nanoparticles. The magnetic nanoparticles functionalized with C1-BTPhen were able to co-extract Am(III) and Eu(III) from nitric acid (HNO3). The extraction efficiency of these C1-BTPhen-functionalized magnetic nanoparticles for both Am(III) and Eu(III) was 20% at 4M HNO3. The interaction between C1-BTPhen and metal cations is reversible. These functionalized magnetic nanoparticles can be used for the co-extraction of traces of Am(III) and Eu(III).
Published online: 5th June, 2013
■ Regioselectivity of the Intramolecular Biaryl Coupling Reaction of 3-Substituted Phenyl 2-Iodobenzoate using a Palladium Reagent
Kazuhiro Maeda, Takuya Matsukihira, Shumpei Saga, Yasuo Takeuchi,* Takashi Harayama, Yoshikazu Horino, and Hitoshi Abe*
*Department of Environmental Applied Chemistry, Faculty of Engineering, Toyama University, Gofuku 3190, Toyama 930-8555, Japan
Abstract
This study investigated the regioselectivity of the intramolecular biaryl coupling reaction of the phenyl benzoate derivative which possesses a methyl or methoxy group at the meta-position of the phenoxy moiety. The type of base and the presence/absence of the phosphine ligand influenced the product ratio. A transition state model and the regioselectivity of the reaction are discussed.
Published online: 12th June, 2013
■ Synthesis of Methoxy-Substituted Diazirinyl Phenylalanine – A Novel Photoreactive Aspartame Derivative for Functional Analysis of Sweet Receptors
Munenori Sakurai, Katsuyoshi Masuda, Lei Wang, Yuta Murai, Yasuko Sakihama, Yasuyuki Hashidoko, Yasumaru Hatanaka, and Makoto Hashimoto*
*Division of Applied Science, Graduate School of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
Abstract
Photoreactive phenylalanine derivatives are well known as functional analysis reagents for target biomolecules. The photophores are commonly introduced at 4-position on benzene. Aspartame, which consists of dipeptide L-Asp-L-Phe-OMe, is one of the most utilized artificial sweeteners, and substitution effects on its benzene ring have been reported. Substitution at the 4-position, however, does not maintain its sweetness properties. Trifluoromethyldiazirine, which is one of the most reliable photophores, was introduced to a different site on phenylalanine and the new photoreactive phenylalanine was converted to aspartame derivatives. The new aspartame derivative had slightly higher sweetness potency than sucrose standard solution.
Published online: 1st July, 2013
■ Expedient Synthesis of 2-Oxopiperazines Using a SN2 / Cope-Type Hydroamination Sequence
Nicolas Das Neves, Michaël Raymond, and André M. Beauchemin*
*Department of Chemistry, University of Ottawa, Ottawa Ontario, K1N 6N5, Canada
Abstract
An approach for the synthesis of 2-oxopiperazines from allylic 2-iodoacetamides and aqueous NH2OH has been developed. The reaction proceeds through a SN2 / intramolecular Cope-type hydroamination sequence yielding in 2-oxopiperazines with moderate to good yield.
Published online: 25th June, 2013
■ Synthesis of Oxygen-Bridged Decahydroazulene Derivatives: Simplified Analogues of Biologically Active Natural Products
Hideki Abe, Akira Tezuka, Toyoharu Kobayashi, and Hisanaka Ito*
*School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
Abstract
Decahydroazulene derivatives having an ether bridge were synthesized. They are structurally simplified analogues of the biologically active guaiane sesquiterpenes englerin A and orientalol F.
Published online: 21st June, 2013
■ Synthesis of 4-Arylpiperidin-4-ol Derivatives of Loperamide as Agents with Potent Antiproliferative Effects against HCT-116 and HL-60 Cells
Noriyuki Hatae,* Tomoyuki Nagayama, Hiroyoshi Esaki, Eiko Kujime, Masabumi Minami, Minoru Ishikura, Tominari Choshi, Satoshi Hibino, Chiaki Okada, Eiko Toyota, Hideko Nagasawa, and Tatsunori Iwamura*
*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan
Abstract
The structure of 4-arylpiperidin-4-ol, a constituent of the antidiarrheal loperamide, is key to μ opioid receptor activation. Some opioid derivatives were recently reported to induce tumor cell death, but the chemical structures responsible for their antitumor activity remain unclear. We synthesized loperamide analogs and tested their antiproliferative activity against HCT-116 colon tumor cells and HL-60 leukemia cells. The N-substituents on 4-arylpiperidin-4-ol units were found to play an important role in their antiproliferative activity, and the N-diphenylpropanol analogs exhibited the most potent antiproliferative activity. Furthermore, the N-diphenylpropanol analog activated caspase-3, as was found previously for opioids that exhibited antitumor effects.
Published online: 2nd July, 2013
■ An Approach to the Synthesis of Novel Dihydroindoles Bearing Electron-Withdrawing Groups at C-2 Position
Fumi Okabe, Hiroshi Maruoka,* Masaru Takasu, Eiichi Masumoto, Toshihiro Fujioka, and Kenji Yamagata
*Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
Abstract
The synthesis of novel dihydroindoles 8a−d and 9a−d bearing electron-withdrawing groups at C-2 position is presented. The key step of this approach is an efficient intramolecular Diels-Alder reaction of N-alkenylated 2-amino-3-furancarbonitriles 4a−d and 5a−d.
Published online: 24th July, 2013
■ Synthetic Studies on Glycosphingolipids from Protostomia Phyla: Synthesis of Glycosphingolipid from the Marine Sponge Spheciospongia vesparia and Its Analogue
Noriyasu Hada, Akira Miyamura, Isao Ohtsuka, and Fumiyuki Kiuchi*
*Faculty of Pharmacy, Keio University, 1-5-30 Shiba-Kouen, Minato-ku, Tokyo, Japan
Abstract
Stereocontrolled syntheses of a neutral glycosphingolipid found from a marine sponge Spheciospongia vesparia and its analogue have been accomplished. Disaccharide glycosphingolipids, β-D-Arap-(1→6)-β-D-Glcp-(1↔1)-Cer (1) and α-D-Arap-(1→6)-β-D-Glcp-(1↔1)-Cer (2), were synthesized from suitable monosaccharide donors and an acceptor by stepwise synthesis.
Published online: 8th July, 2013
■ Two-Directional Synthesis of 2,6-Dimethylpyrrolo[2,3-f]indole-4,8-dione by Double Claisen Rearrangement and Nitrene Cyclization
Andrea Visconti and Christopher J. Moody*
*School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
Abstract
Double Claisen rearrangement of the bis-allyl ether of 2,5-dichloro-1,4-hydroquinone, followed by alkene isomerization, oxidation and double chloride displacement with azide gives 2,5-diazido-3,6-dipropenyl-1,4-benzoquinone. Upon heating, a double nitrene cyclization occurs completing a high yielding, two-directional route to the pyrrolo[2,3-f]indole-4,8-dione ring system.
Published online: 2nd August, 2013
■ One New Megastigmane Glycoside with a Double Bond at a Rare Position from the Leaves of Antidesma pentandrum var. barbatum
Ayumi Iha, Sachiko Sugimoto, Katsuyoshi Matsunami, Hideaki Otsuka,* and Yoshio Takeda
*Divison of Medicinal Chemisry, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
Abstract
From the 1-BuOH-soluble fraction of a MeOH extract of leaves of Anitdesma pentandrum var. barbatum, one new megastigmane glycoside, α-L-arabinofuranosyl-(1→6)-β-D-glucopyranoside of (6ξ,9R)-megastigman-4(13)-en-9-ol, was isolated along with four known megastigmane glycosides, (6R,9R)-megastigma-4,7-dien-9-ol-3-one α-L-arabinofuranosyl-(1→6)-β-D-glucopyranoside, foliasalacinoside B, (6S,9R)-magastigma-4,7-diene-6,9-diol-3-one 9-O-α-L-arabinofuranosyl-(1→6)-β-D-glucopyranoside and byzantionoside B.
Published online: 16th July, 2013
■ Synthesis of the Diazepanone-Nucleoside Core Structure of Liposidomycins and Caprazamycins Based on 7-Exo Cyclization of Epoxyamine
Hiroaki Miyaoka,* Jumpei Wada, and Etsuko Kawashima
*School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
Abstract
The diazepanone-nucleoside core structure of liposidomycins and caprazamycins has been synthesized based on 7-exo cyclization of epoxyamine.
Published online: 31st July, 2013
■ Synthesis of Alkyl 3-Chloroazetidine-3-carboxylates via Regioselective Ring Transformation of Alkyl 2-(Bromomethyl)aziridine-2-carboxylates
Asta Žukauskaitė, Sven Mangelinckx, Algirdas Šačkus, and Norbert De Kimpe*
*Department of Organic Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
Abstract
The synthesis of alkyl 3-chloroazetidine-3-carboxylates was developed by ring transformation of alkyl 2-(bromomethyl)aziridine-2-carboxylates utilizing ring opening with hydrochloric acid at the more sterically hindered carbon atom of the aziridine ring and subsequent base-promoted ring closure.
Published online: 8th August, 2013
■ Synthesis of Novel 5-Aryl/Hetarylidenyl 3-(2-Methyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-yl)-2-thioxothiazolidin-4-ones
Kimberly Mendoza, Sukanta Kamila, and Edward R. Biehl*
*Chemistry Department, Southern Methodist University, Dallas, TX 75275-0314, U.S.A.
Abstract
The synthesis of a variety of novel 5-substituted titled compounds containing a priviledged rhodanine scaffold is described. The synthesis involves a microwave (MW) assisted Knoevenagel condensation of 3-(2-methyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-yl)-2-thioxothiazolidin-4-one with suitably substituted aromatic aldehydes. However, these condensations fail with aliphatic aldehydes. The 2-thioxothiazolidin-4-one (rhodanine) precursor was prepared by the condensation of 2-thioxothiazolidin-4-one-di-(carboxymethyl)trithiocarbonyl and 4,5,6,7-tetrahydrobenzo[4,5]thienyl[2,3-d]- 2-methylpyrimidin-4-amine in the presence of K2CO3.
Published online: 29th July, 2013
■ Synthesis of 8-Amino-(dihydrofuran-Fused Perhydrophenanthrene) via Copper-Mediated Amination Reaction
Kenji Sugimoto, Kosuke Tamura, Naoki Toyooka, and Yuji Matsuya*
*Graduate School of Medicine and Pharmaceutical Sciences for Research, University of Toyama, Sugitani 2630, Toyama, 930-0194, Japan
Abstract
Introduction of nitrogen substituents on a highly functionalized dihydrofuran-fused perhydrophenanthrene (DF) core was examined. Acetamide functionality could be introduced on the DF by copper-mediated Buchwald-type coupling. On the other hand, installation of free amino group on a DF was established via an aryl azide under the copper-mediated condition reported by Helquist and co-workers.
Published online: 31st July, 2013
■ Regio- and Stereoselective Derivatisation of an Aporphine Scaffold
Jonathan D. M. Atkinson, Stephen G. Davies,* and James E. Thomson
*Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
Abstract
Treatment of 10,11-dimethoxyaporphine with chromium hexacarbonyl was found to give two diastereoisomeric products on regioselective co-ordination of the chromium tricarbonyl fragment to the A ring. For one of the diastereoisomeric complexes, alkylation was found to proceed with high regio- and diastereoselectivity at C(4), whereas regio- and diastereoselective alkylation was observed at C(6a) for the other diastereoisomer. In the case of the C(4)- and C(6a)-methylated products, these substrates were decomplexed in high yield to give the corresponding enantiopure, C(4)- and C(6a)-methyl substituted aporphines.