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
Ryoji Noyori's Special Issues, Vol. 76, No. 1, 2008
Published online: 8th May, 2008
■ Oxidative Conversion of Functionalized 3,4-Dihydopyrimidin-2(1H)-ones to the Corresponding Pyrimidin-2(1H)-ones Using Activated Carbon-Molecular Oxygen System
Ken-ichi Okunaga, Yukiko Nomura, Kenjiro Kawamura, Natsuki Nakamichi, Kazuo Eda, and Masahiko Hayashi*
*Department of Chemistry, Graduate School of Science, Kobe University, Nada, Kobe 657-8501, Japan
Abstract
Efficient synthesis of functionalized pyrimidin-2(1H)-ones was achieved by oxidation of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) using activated carbon-molecular oxygen (O2) system. Various DHPMs were easily prepared by Biginelli reactions starting from aldehydes, β-ketoesters and urea. Therefore, the present method provides general and versatile protocol for the synthesis of a variety of functionalized pyrimidin-2(1H)-ones.
Published online: 8th May, 2008
■ Syntheses, Structures, and Properties of Bithiophenophanes Bridged at 1,8-Positions of Naphthalenes
Kazumi Nakao, Tomohiko Nishiuchi, and Masahiko Iyoda*
*Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
Abstract
The 2,2’-bithiophenophanes 2 and 3 bridged at the 1,8-positions of naphthalenes together with the linear dimers 4 and 6, the trimers 5 and 7, and the tetramer 8 were synthesized by the homo-coupling of 1,8-di(5-lithio-2-thienyl)naphthalenes with CuCl2. The cyclophane 2, which has no alkyl substituents, shows a hindered rotation of its bithiophene units to give two isomers, of which the major isomer easily isomerized photochemically to produce the minor isomer. In contrast, 3, which has ethyl substituents, shows a rapid rotation of its bithiophene units in solution to afford a mixture of four conformational isomers, although an X-ray analysis of 3 revealed the existence of only one isomer in crystals. The redox and fluorescence behaviors of 2 and 3 show either a face-to-face interaction of the 2,2’-bithiophene units or deformation of the naphthalene moieties. Furthermore, the linear oligomers 4, 5, 6, 7, and 8 show fairly low oxidation potentials and clear emission owing to the π-π interaction of the face-to-face-stacked thiophene rings.
Published online: 8th May, 2008
■ A Simple Chiral Template for the Synthesis of Fuctionalized α-Arylglycine Derivatives
Hiyoku Nakata, Takahiro Imai, Satoshi Yokoshima, and Tohru Fukuyama*
*Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
Abstract
A simple chiral template for the synthesis of arylglycine derivatives has been developed. The chiral template, which is derived from valinol in three steps, reacts with electron rich aromatic compounds to afford adducts in good yield with moderate to high diastereoselectivities.
Published online: 8th May, 2008
■ Synthesis and Reactivity of 3-Methylsulfinyl-2H-cyclohepta[b]furan-2-ones
Junya Higashi, Kazuyuki Okada, Taku Shoji, Kozo Toyota, Masataka Watanabe, Masafumi Yasunami, Shigeru Kikuchi, Shunji Ito, and Noboru Morita*
*Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
Abstract
2H-Cyclohepta[b]furan-2-ones (2a,b) reacted with dimethyl sulfide dittiflate to give dimethyl(2-oxo-2H-cyclohepta[b]furan-3-yl)sulfonium trifluoromethanesulfonates (3a,b), which were treated with Et3N to give 3-methylthio-2H-cyclohepta[b]furan-2-ones (4a,b). Sulfides 4a and 4b were oxidized with m-CPBA to give corresponding sulfoxides (5a,b) and sulfones (6a,b). The sulfoxides (5a,b) thermally underwent coupling reaction to give 3,3’-bi-2H-cyclohepta[b]furan-2-ones (7a,b). The sulfoxides (5a,b) reacted with trifluoromethanesulfonic anhydride (Tf2O) to afford sulfonium ions 8a and 8b at lower temperature, which reacted with 2a or 2b to give sulfonium ions (9a-c). Treatment of compounds 9a-c with Et2NH or Et3N gave corresponding sulfide products (10a-c).
Published online: 12th May, 2008
■ Phosphinomethyloxazolines as Efficient Ligands for the Iridium-Catalyzed Enantioselective Hydrogenation of Unfunctionalized Tetrasubstituted Olefins
Marcus G. Schrems, Eva Neumann, and Andreas Pfaltz*
*Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland
Abstract
Iridium-catalyzed enantioselective hydrogenation has become the method of choice for the enantioselective reduction of unfunctionalized olefins. In particular, tetrasubstituted olefins are interesting substrates, which allow the generation of two adjacent stereocenters in a single hydrogenation step. For this class of substrates, chiral phosphinomethyl-oxazolines have proved to be very efficient ligands. Herein we report a short and practical synthesis of differently substituted phosphinomethyl-oxazolines and the corresponding iridium(COD) complexes. The scope of these catalysts is demonstrated by hydrogenation studies of four tetrasubstituted olefins.
Published online: 8th May, 2008
■ Facile Synthesis of Diarylmethylpyridines/Diarylmethylquinolines through Superelectrophilic Activation of Pyridinecarboxaldehydes/Quinolinecarboxaldehydes with Boron Trifluoride Monohydrate
G. K. Surya Prakash,* Farzaneh Paknia, Sujith Chacko, Thomas Mathew, and George A. Olah*
*Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California, 90089-1661, USA
Abstract
Synthesis of diarylmethylpyridines and diarylmethylquinolines has been achieved by Friedel-Crafts hydroxyalkylation reactions of pyridinecarboxaldehydes and quinolinecarboxaldehydes with aromatic compounds under superelectrophilic activation using boron trifluoride monohydrate system (BF3-H2O). Since BF3-H2O is more economic, easy to prepare and offers high acidity (H0 -12), this method using BF3-H2O is found to be more convenient and useful compared to the methods reported earlier. The reaction is very simple and clean, eliminating the use of organic solvents and other expensive acid systems. Products are obtained in high yields and purity in most cases.
Published online: 1st May, 2008
■ Development of Bifunctional Acylic Hydroxyl-Guanidine Organocatalyst: Application to Asymmetric Nucleophilic Epoxidation
Bongki Shin, Shinji Tanaka, Tetsuya Kita, Yuichi Hashimoto, and Kazuo Nagasawa*
*Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
Abstract
Asymmetric epoxidation of α,β-unsaturated ketones using acyclic 3a as a new bifunctional organocatalyst is described. The hydroxyl-guanidine 3a promoted the reaction to give the corresponding epoxy ketones in good yields (up to 99% yield) and enantioselectivities (up to 73% ee).
Published online: 18th January, 2008
■ Synthesis of Diazirine Possessing an Acetophenone Derivative as a Valuable Intermediate for a Flavonoid Photoaffinity Probe
Takumi Furuta,* Mitsuru Ueda, Yasuo Hirooka, Kiyoshi Tanaka, and Toshiyuki Kan*
*School of Pharmaceutical Sciences, University of Shizuoka and Global COE program, 52-1 Yada, Shizuoka, 422-8526, Japan
Abstract
A novel acetophenone derivative with a diazirine moiety is prepared as a potential intermediate for a flavonoid photoaffinity probe. The transformation to the flavanone derivative with a diazirine moiety on the A-ring is also demonstrated.
Published online: 22nd February, 2008
■ Effect of the Use of Bulky Alkylphosphines in the Sonogashira Coupling with Aqueous Ammonia
Sachio Fukuoka, Tetsuro Naito, Hiroki Sekiguchi, Takashi Somete, and Atsunori Mori*
*Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
Abstract
The Sonogashira coupling of terminal alkynes and aryl bromides with aqueous ammonia catalyzed by the in situ formed palladium complex of a bulky alkylphosphine furnishes the coupling product at room temperature. One-pot reaction of the Sonogashira coupling and the following intramolecular cyclization with 2-hydroxy or 2-amino aryl bromide leads to a facile synthesis of benzofuran and indole derivatives.
Published online: 7th March, 2008
■ A Straightforward Synthesis of Pyran[2’,3’:4,5]furo[3,2-b]pyran from Furan
Ana Aljarilla and Joaquín Plumet*
*Department of Organic Chemistry, Faculty of Chemistry, University Complutense, 28040-Madrid, Spain
Abstract
A convenient synthesis of the title compound 1 and the related lactone 2 has been achieved through a sequence involving a Diels-Alder reaction with vinylene carbonate followed by a ring-opening metathesis (ROM)-ring closing metathesis (RCM) tandem reaction of the corresponding oxabicyclic intermediate.
Published online: 4th April, 2008
■ Synthesis of Chiral (Sulfinyl)furyloxazoline Ligands and Its Application to Enantioselective Palladium-Catalyzed Allylic Alkylation
Yusuke Bunya, Takaaki Sengoku, Yoko Imamura, and Yoshitsugu Arai*
*Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi Gifu 502-8585, Japan
Abstract
Chiral ligands containing an oxazoline substituent and a sulfur
functionality at the furan ring have been synthesized and examined for
enantioselective palladium catalyzed allylic substitution reaction. The
enantioselectivity observed was found to be dependent upon the nature of the sulfur center and oxazoline group, up to 91% ee was given with chiral
(3-sulfinyl)furan-2-yl ligand.
Published online: 1st April, 2008
■ Staphylosides A and B: Two New Chromone Diglucosides from Leaves of Staphylea bumalda DC.
Etsuko Sueyoshi, Qian Yu, Katsuyoshi Matsunami, and Hideaki Otsuka*
*Department of Pharmacognosy, Graduate School of Biomedical Sciences, Hiroshima University; 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
Abstract
Two new chromone diglucosides, staphylosides A and B (4 and 5), were isolated from the leaves of Staphylea bumalda DC., along with three known chromone glycosides. Their structures were elucidated by detailed inspection of NMR spectral data.
Published online: 15th May, 2008
■ Carbon-Carbon Bond Formation between Enone and Ester Carbonyl Group Induced by Samarium Diiodide
Masakazu Sono,* Takayuki Mizutani, Masayo Nozaki, Shigeru Takaoka, and Motoo Tori*
*Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 770-8514, Japan
Abstract
Reductive cyclization of methyl, TBDMS, pentafluorophenyl, trichloroethyl, or MOM ester of 4-(2-methyl-6-oxocyclohex-1-enyl)butanoic acid was attempted by treating with SmI2, with or without additive (MeOH, H2O, HMPA, NiI2), to establish whether Claisen-type carbon-carbon bond formation occurred. Methyl ester afforded dimeric products, while trichloroethyl and MOM ester yielded hexahydronaphthalenediones. Pentafluorophenyl ester gave a spiro compound. It is thought that all these products were formed through an anionic intermediate produced by two-electron reduction of the enone moiety by SmI2.
Published online: 17th April, 2008
■ Straightforward Asymmetric Total Synthesis of (+)-Evodiamine, a Major Indole Alkaloid in Herbal Medicine “Wu Zhu Yu”
Atsushi Nakayama, Noriyuki Kogure, Mariko Kitajima, and Hiromitsu Takayama*
*Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Chiba 263-8522, Japan
Abstract
The concise asymmetric total synthesis of evodiamine, an indole alkaloid in Evodia Fructus, was achieved by employing Noyori’s ruthenium(II)-catalyzed asymmetric transfer hydrogenation.
Published online: 8th May, 2008
■ Flavisiamines E-F and Fruticosiamine A, New Methyl Chanofruticosinate- and Aspidofractinine-Type Indole Alkaloids, from Two Species of Kopsia
Mitsuhiro Sekiguchi, Yusuke Hirasawa, Kazumasa Zaima, Teh Chin Hoe, Kit-Lam Chan, and Hiroshi Morita*
*Faculty of Pharmaceutical Sciences, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
Abstract
Two new methyl chanofruticosinate-type indole alkaloids, flavisiamines E (1) and F (2), and an aspidofractinine-type indole alkaloid, fruticosiamine A (3), have been isolated from Kopsia flavida and K. fruticosa, respectively and their structures were elucidated by NMR spectral analysis using 2D techniques.
Published online: 8th May, 2008
■ Enantiomeric Resolution of Racemic C2-Symmetric trans-2,5-Dimethyl-2,5-diphenylpyrrolidine and trans-2,5-Dimethyl-2,5-bis(3-hydroxyphenyl)pyrrolidine by a Diastereomer Method
Yoshiaki Uchida, Yoichi Nakayama, Katsuaki Suzuki, Shigeaki Oki, Masahiro Horiguchi, Hirohito Tsue, and Rui Tamura*
*Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
Abstract
The racemic samples of C2-symmetric trans-2,5-dimethyl-2,5-diphenylpyrrolidine (trans-2a) and trans-2,5-dimethyl-2,5-bis(3-hydroxy- phenyl)pyrrolidine (trans-2b) have been resolved by the diastereomer method using D- or L-tartaric acid as the resolving agent. The enantiomerically enriched trans-2a and trans-2b could be oxidized with Oxone® to give trans-2,5-dimethyl-2,5-diphenylpyrrolidine-1-oxy (trans-1a) and trans-2,5-dimethyl-2,5-bis(3- hydroxyphenyl)pyrrolidine-1-oxy (trans-1b), respectively.