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
Keiichiro Fukumoto's Special Issues, Vol. 77, No. 1, 2009
Published online: 2nd June, 2008
■ Preparation of a Building Block for a Pyrazole Expanded Porphyrin and Isolation of a Tripyrrolyl Ketone Decomposition Product
Alfred Hassner* and Eran Fogler
*Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
Abstract
Dipyrrolylpyrazole 3, obtained from 1,3-di-(1H-pyrrol-2-yl)propane-1,3-dione (2), was prepared as a building block for pyrazole-based binuclear expanded porphyrins. An unusual transformation of 2, in solution or on chromatography, afforded 1,3,3-tri-(1H-pyrrol-2-yl)prop-2-en-1-one (4) in good yield. HRMS indicated the presence of an unstable pyrazole-based expanded porphyrin 1 and its trinuclear Mg derivative 5 on condensation of 3 with benzaldehyde.
Published online: 10th July, 2008
■ Ring Contraction of α,β-Unsaturated Cyclic Amines with cis-Dihydroxylation at the α,β-Position
Samuel S. Libendi, Yosuke Demizu, Yoshihiro Matsumura, and Osamu Onomura*
*Department of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
Abstract
α,β-Unsaturated cyclic amines are oxidized by OsO4 to afford α,β-cis-dihydroxylated compounds which are thermodynamically transformed into ring-opened keto-alcohols. The keto-alcohols are then cyclized to form synthetically useful ring-contracted cyclic amines.
Published online: 30th June, 2008
■ An Improved Synthesis of 1-epi-ED-71, a Biologically Interesting Diastereomer of 1α,25-Dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (ED-71)
Kohei Eto, Ayako Fujjiyama, Mai Kaneko, Keisuke Takahashi, Jun Ishihara, Susumi Hatakeyama, Yoshiyuki Ono, and Noboru Kubodera*
*Chugai Pharmaceutical Company, Ltd., 2-1-1, Nihonbashi-Muromachi, Chuo-ku, Tokyo 103-8324, Japan
Abstract
A linear synthesis and an improved convergent synthesis of biologically interesting 1-epi-ED-71, a diastereomer of 1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (ED-71) at the 1-position of the A-ring, are described.
Published online: 21st August, 2008
■ Efficient Synthesis of Three Types of Sialyl 6-O-Sulfo Lewis X: Probes for the Comprehensive Search for the Interaction between Carbohydrates and Other Biomoleclues
Masanori Yamaguchi, Hideharu Ishida, and Makoto Kiso*
*Graduate School of Agriculture, Gifu University, 1-1 Yanagito, Gifu, Gifu 501-1193, Japan
Abstract
Synthesis of three kinds of 6-O-sulfated sLex glyco probes with their relevance to ligand processing pathway of L-selectin has been described. The glycosylation of the suitably protected hexasaccharide acceptor 6 with the sialyl-α-(2→3)-D-galactopyranosyl SMe donors (3 and 4) using dimethyl(methylthio)sulfonium triflate (DMTST), afforded the protected tetrasaccharides 7 and 8, respectively. Removal of all the benzyl protecting groups and the subsequent acetylation afforded the sLex derivatives (9 and 10), which were converted to the target compounds (15 and 16) by the selective removal of 4-methoxyphenyl group, followed by 6-O-sulfation of the GlcNAc residue, and removal of all the protective groups under basic conditions. Finally 16 was lactamized with HBTU and HOBT, to give the desired target compound 17.
Published online: 31st July, 2008
■ A Transannular Diels-Alder Strategy to the Construction of the CDE Ring System of Nakiterpiosin
Hiroyoshi Takamura,* Yuji Yamagami, Tomonori Ito, Masahiro Ito, Hirokazu Arimoto, Isao Kadota, and Daisuke Uemura
*Division of Chemsitry and Biochemistry, Graduate School of Natural Science and Technology, Okayama University
Abstract
The transannular Diels-Alder (TADA) reaction was applied to the synthesis of the CDE ring system of nakiterpiosin (1). TADA product 28 is a key intermediate toward the total synthesis of 1.
Published online: 28th July, 2008
■ Highly Regioselective Rearrangement of 2,3-Diaryloxiranes into 2,2-Diarylacetaldehydes Catalyzed by Ytterbium Porphyrin Complex Yb(TPP)OTf
Toshikatsu Takanami,* Shin-ichiro Nakajima, Shoichi Nakadai, Fumio Hino, and Kohji Suda*
*Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan
Abstract
[5,10,15,20-Tetraphenylporphynato]ytterbium(III) triflate, Yb(TPP)OTf, is an efficient Lewis acid catalyst for the highly regioselective rearrangement of 2,3-diaryl¬oxiranes into 2,2-diarylacetaldehydes. The catalytic process can be easily performed not only in dichloroethane but also in a more environmentally friendly solvent, benzotrifluoride.
Published online: 18th August, 2008
■ Semi-quantitative Approaches to the Coordination Ability of o-Bisguanidiniobenzenes with Metal Salts
Koji Suda, Noriko Saito, Takuya Kumamoto, Waka Nakanishi, Masatoshi Kawahata, Kentaro Yamaguchi, Yasumitsu Ogura, Kazuo T. Suzuki, and Tsutomu Ishikawa*
*Graduate School of Pharmaceutical Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
Abstract
In order to uncover the potential functionality of o-bisguanidinobenzenes the ability of 1,2-bis(1,3-diethylethyleneguanidino)benzene to form complexes with eighteen kinds of metal salts in aqueous media was examined. Complex formation ability was judged by spectral analysis, including elemental analysis, of products obtained as water-insoluble precipitates, as water-soluble and chloroform-extractable materials, or as water-soluble and chloroform-unextractable materials. Positive coordination was observed with many metal salts used. Tight water-insoluble and crystalline complexes were formed in the cases of cobalt(II), zinc(II), and cadmium(II) salts, in the first two cases among which products were analyzable by X-ray crystallography. In addition, treatment of the complex with aqueous alkali re-produced the original bisguanidinobenzene quantitatively, indicating the promising use as a recyclable ligand.
Published online: 18th August, 2008
■ Reaction of 1-Azabicyclo[1.1.0]butanes with 2,3-Dicyanofumarates; Interception of the Intermediate Zwitterions with Methanol
Grzegorz Mloston,* Malgorzata Celeda, Anthony Linden, and Heinz Heimgartner*
*Institute of Organic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
Abstract
The reaction of 3-phenyl-1-azabicyclo[1.1.0]butane (1c) with 2,3-dicyanofumarates ((E)-5) in dichloromethane at room temperature yields mixtures of cis- and trans-2,3-dicyano-4-phenyl-1-azabicyclo[2.1.1]hexane- 2,3-dicarboxylates (cis,trans-4). The proposed two-step reaction mechanism via a zwitterionic intermediate of type (6) is supported by trapping experiments with methanol: when the reactions of 1-azabicyclo[1.1.0]butanes (1) with dimethyl 2,3-dicyanofumarate ((E)-5a) are carried out in methanol, dimethyl (E)-2-(azetidin-1-yl)-3-cyanobut-2-enedioates (7) are formed as the only products.
Published online: 25th August, 2008
■ 7-Acylated Anthocyanins with p-Hydroxybenzoic Acid in the Flowers of Campanula medium
Kenjiro Toki,* Norio Saito, Hiroyuki Nishi, Fumi Tatsuzawa, Atsushi Shigihara, and Toshio Honda
*Laboratory of Floriculture, Faculty of Floriculture, Minami-Kyushu University, 11609 Takanabe, Koyu-gun, Miyazaki 884-0003, Japan
Abstract
Three anthocyanins were isolated from the 50% acetic acid extract of the light blue-purple flowers of Campanula medium, ‘May Blue’. Among them, a new acylated anthocyanin was elucidated to be delphinidin 3-[6-O- (α-rhamnopyranosyl)-β-glucopyranoside]-7-O-[6-O-(4-O-(β-glucopyranosyl)-p- hydroxybenzoyl)-β-glucopyranoside] (5) as a main anthocyanin, together with two known anthocyanins, violdelphin (4) and delphinidin 3-O-rutinoside-7-O-glucoside (6) as minor anthocyanins. On anthocyanin components, three other cultivars of C. medium were investigated by HPLC analysis, and found that campanin (3) was present in the purple flowers of ‘May Purple’ as a main anthocyanin, rubrocampanin (1) was present in the pink flowers of ‘May Pink’ as a main anthocyanin, and purprocampanin (2) and rubrocampanin (1) were present in the purple-red flowers of ‘May Purple Margin’as major anthocyanins. From these results, the relations between the flower colors and anthocyanin components were discussed in the flowers of C. medium cultivars.
Published online: 31st July, 2008
■ [4+2] Cycloaddition of Diphenylketene to 1-Aza-1,3-dienes
Masanori Sakamoto,* Tatsuya Nakai, Hiroaki Yanagisawa, and Tomomi Kawasaki
*Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan
Abstract
On heating 3-cyano-1-aza-1,3-dienes 5, 6 and 9 with diphenylketene, [4+2] cycloaddition took place smoothly to afford the corresponding piperidin-2-one derivatives 7, 8 and 10 in high yields, respectively.
Published online: 21st August, 2008
■ Synthesis of 5-Amino and 4-Hydroxy-2-phenylsulfonylmethylpiperidines
Julien Massé and Nicole Langlois*
*Institut de Chimie des Substances Naturelles, CNRS, 91198 Gif-sur-Yvette Cedex, France
Abstract
Suitable protected 5-amino- and 4-hydroxy- 2-phenylsulfonylmethylpiperidines were synthesized from functionalized N-benzyloxycarbonylpiperidin-2-ones through the opening of lactam ring by methyl phenyl sulfone carbanion followed by reductive aminocyclization.
Published online: 31st July, 2008
■ Wittig Rearrangement of 3-Furylmethyl Ethers: Facile Synthesis of 3-Methyl-2-furylmethanols and 3-Furylethanols
Masayoshi Tsubuki,* Hiroyuki Okita, Kazunori Kaneko, Atsushi Shigihara, and Toshio Honda*
*Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
Abstract
Wittig rearrangement of 3-furylmethyl ethers 1a-i was investigated. Deprotonation of 3-furylmethyl ethers 1a-i with bases, such as BuLi and LDA, occurred preferentially at the allylic, propargylic, benzylic positions and α-position adjacent to carbonyl group giving the corresponding anions, which underwent 2,3- and 1,2-rearrangements to afford 3-methyl-2-furylmethanols 2a-i and 3-furylethanols 3a-f,h,i. Synthesis of naginata ketone and dendrolasin was achieved employing the Wittig rearrangement as a key step.
Published online: 25th August, 2008
■ Formation of O-Glycosidic Linkages from 1-Hydroxy Sugars by Bismuth(III) Triflate-catalyzed Dehydrative Glycosidation
Takashi Yamanoi,* Ryo Inoue, Sho Matsuda, Kazuya Iwao, Yoshiki Oda, Akihiro Yoshida, and Keita Hamasaki
*The Noguchi Institute, 1-8-1, Kaga, Itabashi-ku, Tokyo 173-0003, Japan
Abstract
This paper describes the direct formation of various O-glycosidic linkages from 1-hydroxy sugars by bismuth(III) triflate-catalyzed dehydrative glycosidation. The condensation reactions of 1-hydroxy sugars with some primary alcohols in the presence of only 5 mol% bismuth(III) triflate at reflux temperature for 15 min in dichloromethane afforded O-glycosides in good yields. An 1,6-anhydro-β-D-glucopyranosidic linkage was formed by the intramolecular condensation of the corresponding 1-hydroxy sugar performed with similar reaction conditions using 5 mol% bismuth(III) triflate. A reaction using 10 mol% bismuth(III) triflate at room temperature in dichloromethane promoted the self- or cross-condensations of 1-hydroxy sugars to produce several kinds of 1,1’-disaccharides. This paper reports some important properties of bismuth(III) triflate catalyzed dehydrative glycosidation using 1-hydroxy sugars to form various O-glycosidic linkages.
Published online: 1st September, 2008
■ Reaction of β,β-Bis(trifluoroacetyl)vinyl Esters and β-Trifluoroacetylvinyl Esters with 1,2-Phenylenediamines Accessing Fluorine-containing Benzo[b][1,4]diazepine Derivatives — A Study about the Reaction Based on Molecular Orbital Calculations
Norio Ota, Yasuhiro Kamitori,* Takehisa Tomoda, Naoya Terai, and Etsuji Okada*
*Department of Chemical Science and Engineering, Faculty of Engineering, Kobe University, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
Abstract
β,β-Bis(trifluoroacetyl)vinyl ether (1) reacted with 1,2-phenylenediamine to give dihydrobenzodiazepinol (4a) selectively, whereas β-trifluoroacetylvinyl ether (2) and β-trifluoroacetyl-α-phenylvinyl ether (3) gave the corresponding O-N exchange products (6b, c) when reacted with 1,2-phenylenediamine. The factors determining the reaction products of the reaction of three substrates 1-3 having similar structures with 1,2-phenylenediamine were elucidated on the basis of molecular orbital calculations. The dehydration processes from dihydrobenzodiazepinols (4 and 8) to benzodiazepines (5 and 7) are also discussed.
Published online: 25th August, 2008
■ Preparation of New Nitrogen-bridged Heterocycles. 64. A Smooth Formation of 2,4-Diarylpyrido[2,3-b]indolizine-10-carbonitrile Derivatives
Akikazu Kakehi,* Hiroyuki Suga, and Shuichi Sato
*Department of Chemistry and Material Engineering, Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
Abstract
The syntheses of the title compounds from the reactions of 2-amino-3-(arylcarbonyl)indolizine-1-carbonitriles with various acetophenones in the presence of strong base were investigated. When the reactions were carried out between 2-aminoindolizines and 1.2-equimolar amounts of acetophenones, the yields for the target molecules were low or very low. However, when a large excess of acetophenones were used without any solvent or in as small as amount of solvent as possible, their yields were considerably improved. The smooth hydrolysis of the 10-cyano group to the carbamoyl one was also observed.
Published online: 25th August, 2008
■ Total Synthesis of 2-Nor-macrosphelide A and B
Yuji Matsuya,* Takashi Matsushita, Keiji Sakamoto, and Hideo Nemoto*
*Faculty of Pharmaceutical Sciences, Toyama University, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
Abstract
Total synthesis of 2-nor-macrosphelides, a 15-membered analogue of 16-membered natural macrosphelides, is described. The synthesis was accomplished starting from methyl L-(+)-lactate as a sole chiral source with a high efficiency.
Published online: 25th August, 2008
■ Synthesis of 6Z-Pandanamine by Regioselective Cyclization Reaction of 2-En-4-ynoic Acid Derivatives Promoted by Weak Base
Kou Hiroya,* Kazuya Takuma, Kiyofum Inamoto, and Takao Sakamoto
*Graduate School of Pharmaceutical Science, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan
Abstract
The stereoselective synthesis of 6Z-pandanamine by base-promoted 5-exo-dig-selective cyclization reaction of bis-2-en-4-ynoic acid derivative as a key step is described.
Published online: 3rd September, 2008
■ Synthesis and Biological Activities of VDR Antagonists; 25-Modified 1α,25-Dihdyroxyvitamin D3-26,23-Lactam (DLAM) Derivatives
Yuko Kato-Nakamura, Jun-ichi Namekawa, Seiichi ishizuka, Hiroshi Saitoh, Kazuya Takenouchi, and Kazuo Nagasawa*
*Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan
Abstract
Three series of DLAM (1α,25-dihydroxyvitamin D3-26,23-lactam) derivatives (9 compounds) with 25-modification were synthesized. The biological evaluation of these derivatives revealed that the bulkiness at the 25-position of the DLAM causes a decrease in both the binding affinity for VDR and antagonistic activity.
Published online: 28th August, 2008
■ Cooper/HP20: Novel and Polymer-Supported Copper Catalyst for Huisgen Cycloaddition
Yoshiaki Kitamura, Kazum taniguchi, Tomohiro Maegawa, Yasunari Monguchi, Yukio Kitade, and Hironao Sajiki*
*Laboratory of Medicinal Chemistry, Gifu Pharmaceutical University, 6-1 Mitahora-higashi 5-chome, Gifu 502-8585, Japan
Abstract
A polymer-supported copper catalyst (Cu/HP20) is easily prepared in water and effectively catalyzed the Huisgen cycloaddition between azides and terminal alkynes.
Published online: 1st September, 2008
■ Stereoslelctive Synthesis of a 4a,9-Disubstituted Octahydroacridine from Isatin
Hideki Abe, Yoshimi Sato, Kazuhiro Watanabe, Sakae Aoyagi,* Chihiro Kibayashi, and Tadashi Katoh*
*Department of Synthetic Organic Chemistry, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
Abstract
An efficient method for stereoselective synthesis of a 4a,9-disubstituted octahydroacridine derivative from isatin (2,3-indolinedione) was developed; the method is based on an intramolecular reaction of an N-acyliminium ion with a conjugated diene system.
Published online: 1st September, 2008
■ Acetal — Bearing Rearranged Vibsane-Type Diterpenoids from Viburnum awabuki
Miwa Kubo, Yuka Minoshima, Daiki Arimoto, Hiroyuki Minami, Kenichi Harada, Hideaki Hioki, and Yoshiyasu Fukuyama*
*Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihamabouji, Yamashiro-machi, Tokushima, 770-8514, Japan
Abstract
Neovibsanin J (1), neovibsanin K (2), and neovibsanin P (3), unique vibsane-type diterpenoids bearing an acetal moiety at the C-7 position, were isolated from the leaves of Viburnum awabuki and their structures were elucidated by NMR spectral analysis using 2D techniques.
Published online: 1st September, 2008
■ Regioselective Nitroso Diels-Alder Cycloaddition Reactions of 5-Dienyl Pyrimidinones and Transformation to Novel 4-Amino-alcohol Tethered Pyrimidinones
Amit Anand, Gaurav Bhargava, Pardeep Singh, and Mohinder P. Mahajan
*Department of Applied Chemistry, Guru Nanak Dev University, Amritsar 143 005, Punjab, India
Abstract
A highly regioselective nitroso Diels-Alder (NDA) cycloaddditon of nitroso benzene with variedly substituted 5-dienyl pyrimidinones with and the transformation of adducts to novel, unnatural, biologically important 4-amino alcohols is reported.
Published online: 7th March, 2008
■ Secoiridoid Di-glycosides from Osmanthus ilicifolius
Shigeaki Sakamoto, Koichi Machida, and Masao Kikuchi*
*Department of 2nd Analytical Chemistry, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
Abstract
Four new secoiridoid di-glycosides, 3’-O-β-D-glucopyranosyl ligustroside (1), 3’-O-β-D-glucopyranosyl 10-acetoxyligustroside (2), 3’-O-β-D- glucopyranosyl oleuropein (3) and 3’-O-β-D-glucopyranosyl 10-acetoxyole- uropein (4) were isolated from the leaves of Osmanthus ilicifolius. Their structures were established on the basis of chemical and spectral data. Furthermore, the structure of hiiragilide, previously elucidated to be 2’-O-β-D-glucopyranosyl 10-hydroxyligustroside, was revised as 3’-O-β-D-glucopyranosyl 10-hydroxyligustroside (5).
Published online: 15th May, 2008
■ Synthesis of [Poly(2-pyridyl)-Substituted]-1-azaazulenes
Tomoyuki Ariyoshi, Tomonori Noda, Satomi Watarai, Shoji Tagashira, Yoshiko Murakami, Hiroyuki Fujii, and Noritaka Abe*
*Graduate School of Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan
Abstract
2-(2-Pyridyl)-1-azaazulenes were derived from 2-bromo- or 2-iodo-1-azaazulenes and 3-(2-pyridyl)-1-azaazulenes were derived from 3-iodo-1-azaazulenes by Suzuki coupling. Reaction of 3-iodo-1-azaazulenes with B(NPDEA) gave corresponding 3-(2-pyridyl)-1-azaazulenes together with 3-borylated-2-chloor-1-azaazulene (9a) or 3,3’-bi(2-methoxy-1-azaazulene) (10b). Reactions of 8-(2-pyridyl)-1-azaazulene with 2-pyridyllithium gave 4,8-di(2-pyridyl)- and 6,8-di(2-pyridyl)-1-azaazulenes. Reactions of 4,8-di(2-pyridyl)-1-azaazulene with 2-pyridyllithium gave 4,6,8-tri(2-pyridyl)-1-azaazulene. The reactivity of the seven-menbered ring is C8 > C6 > C4. Reaction of 3-(2-pyridyl)-1-azaazulenes with 2-pyridyllithium gave 3,4-di(2-pyridyl)- and 3,8-di(2-pyridyl)-1-azaazulenes.
Published online: 26th June, 2008
■ 8-Endo-Selective Aryl Radical Cyclization Leading to 3-Benzazocines
Tsuyoshi Taniguchi, Hisaaki Zaimoku, and Hiroyuki Ishibashi*
*Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
Abstract
Bu3SnH-mediated radical cyclization of N-acyl-3-(2-bromophenyl)-N-ethenypropylamines (14) occurred in an endo-selective manner to give the 3-benzazocine derivatives (15) in good yields.
Published online: 10th July, 2008
■ Catalytic Asymmetric Intramolecular Allylation of Aldehyde
Tomohiro Sato and Kiyoshi Tomioka*
*Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-shimoadachi-machi, Sakyo-ku, Kyoto 606-8501, Japan
Abstract
The intramolecular asymmetric allylation of aldehydes was catalyzed by a combination of pyrrolidine derivatives and Pd(0) to give 5-exo-cyclized aldehyde with fair ee in good yield.
Published online: 3rd July, 2008
■ Synthesis and Properties of Disk-Shaped Bipolar Symmetric Cyclic Triindole Derivative
Hidetaka Hiyoshi,* Tetsuya Aoyama, Tatsuo Wada, Takaaki Sonoda, and Shuntaro Mataka
*Planning Section, Development Department, Ihara Chemical Industry Co., Ltd., 4-26 Ikenohata 1-chome, Taito-ku, Tokyo 110-0008, Japan
Abstract
The 1,3,4-oxadiazole-substituted donor-π-acceptor cyclic triindole, 5,10,15-tris(2-ethylhexyl)-2,7,12-tris-[4-(4-t-butylphenyl-1,3,4-oxadiazol-2-yl)- phenyl]-10,15-dihydro-5H-5,10,15-triazadiindeno[1,2-a;1’,2’-c]fluorene (3), showed an electroluminescence in a single-layer device which was fabricated by a spin-coating process.
Published online: 18th August, 2008
■ Dihydroxylation of Functionalized Coumarin Derivatives
Keiko Fusegi, Takuya Kumamoto,* Waka Nakanishi, and Tsutomu Ishikawa*
*Graduate School of Pharmaceutical Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
Abstract
7-Acetoxy- and 7-tosyloxycoumarins were successfully dihydroxylated in RuCl3/NaIO4/CeCl3 system to give the corresponding glycol derivatives in excellent yields. Tricyclic coumarin with tetrasubstituted olefin function also gave the desired diol in good yield. Introduction of electron-deficient protecting group to coumarin skeleton is critical for the successful dihydroxylation.
Published online: 18th August, 2008
■ Facile and Efficient Synthesis of Novel Oxazine, Oxazepine and Phenoxazine of Chromenones Fused with 1,4-Naphthoquinone
Vishnu K. Tandon* and Hardesh K. Maurya
*Department of Chemistry, University of Lucknow, Lucknow, U.P. 226007, India
Abstract
A series of novel mono ethers 5, 7, diethers 6, 8, 9, oxazine 10, oxazepine 11 and phenoxazines 12 of chromenones fused with 1,4-naphthoquinone have been synthesized.
Published online: 7th August, 2008
■ Diels-Alder Reaction of 2-(Cyclic Amino)-substituted 3-Furancarbonitriles with Maleimides to Phthalimides
Hiroshi Maruoka,* Fumi Okabe, Yoshimichi Koutake, Toshihiro Fujioka, and Kenji Yamagata
*Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
Abstract
An efficient Diels-Alder reaction is described in the furan series, leading to phthalimides in high yields. Thermal treatment of 2-(4-morpholinyl, 1-piperidinyl, and 1-pyrrolidinyl)-3-furancarbonitriles with maleimide derivatives, e.g. maleimide, N-methylmaleimide, N-benzylmaleimide, N-phenylmaleimide and N-(4-nitrophenyl)maleimide, in boiling acetic acid caused a [4 + 2] cycloaddition reaction to give the corresponding phthalimide derivatives.