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
Tetsuji Kametani's Special Issues, Vol. 30, No. 2, 1990
Published online:
■ The Synthesis of 8-Amino-6-N-methyl-1,2,3,5,6,7-hexaazaacenaphthylene
Andrew Van Sickle, Andrew M. Kawasaki, and Leroy B. Townsend*
*Department of Medical Chemistry, College of Pharmacy, University of Michigan , 930 North University, Ann Arbor, MI 48109-1055, U.S.A.
Abstract
The protected tricyclic heterocycle 8-amino-6-N-methyl-2-(tetrahydropyran-2-yl)-1,2,3,5,6,7-hexaazaacenaphthylene (11) was prepared from3-cyano-4,6-bis-methylthiopyrazolo[3,4-d]pyrimidine (5) in a six-step reaction sequence. Treatment of 11 with hydrogen chloride gas under anhydrous conditions has afforded 8-amino-6-N-methyl-1,2,3,5,6,7-hexaazaacenaphthylene (4) in a moderate yield.
Published online:
■ Oxaziridines and Nitrones as Potential Inhibitors of Bacterial D,D-Peptidases
Jacqueline Marchand-Brynaert, Zoubida Bounkhala-Khrouz, Huguette Vanlierde, and Léon Ghosez*
*Laboratoire de Chimie Organique de Synthèse, Université Catholique de Louvain, Place Louis Pasteur 1, B-1348 Louvain-la-Neuve, Belgium
Abstract
Novel functionalized oxaziridines and nitrones have been prepared and examined as potential irreversible inhibitors of bacterial PBPs. N-(β-Hydroxycarbonyl)ethyloxaziridines were found to undergo a fast isomerisation in protic solvent to yield the corresponding nitrones.
Published online:
■ Photoreaction of Benzenecarbothioamide with Olefins. Syntheses of Isothiazole Derivatives and Phenones
Kazuaki Oda, Minoru Machida,* and Yuichi Kanaoka
*Faculty of Pharmaceutical Scicences, Higashinihonngakuen University, 1757 Kanazawa, Toubetu-cho, Ishikari-gun, Hokkaodo 061-0212, Japan
Abstract
Photoreaction of benzenecarbothioamide (1) in the presence of olefins gave isothiazole derivatives (10, 12, and 13) and 3,5-diphenyl-1,2,4-thiadiazole (11) under aerobic conditions, whereas under nitrogen atmosphere gave phenones (3 and 4).
Published online:
■ Structure-Activity Relationships of Pseudoguaianolides Isolated from Gaillardia pulchella and Their Derivatives
Kenzo Harimaya and Seiichi Inayama*
*Pharmaceutical Institute, School of Medicine, Keio University, Shinanomachi 35, Shinjuku, Tokyo 160-0016, Japan
Abstract
Three new pseudoguaianolides, 4-epipulchellin (1), 4-epineopulchellin (2) and pulchelloid D (3), were isolated from Gaillardia pulchella together with other eleven pseudoguaianolides and three guaianolides. Fifteen natural sesquiterpene lactones and their thirty one derivatives were tested for cytotoxic activity against KB cell line. Among them, twenty seven compounds were shown to be active (ED50 < 4 μg/ml). The structure-activity relationships of these sesquiterpene lactones are discussed.
Published online:
■ Studies of as-Triazine Derivatives. XV. Intramolecular Reverse-Election Demand Diels-Alder Reaction of 1,2,4-Triazine Derivatives
Mataichi Sagi, Kunio Wada, Shoetsu Konno, and Hiroshi Yamanaka*
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
5,6-Diphenyl-1,2,4-triazine-3-carboxylic acid esters which have acetylenic function in the alcoholic moiety of the ester group were converted to the pyridine derivatives condensed with lactone ring by means of intramolecular reverse electron-demand Diels-Alder reaction. This type ring-transformation was applicable to the corresponding 3,5-diphenyl-1,2,4-triazine-6-carboxylic acid esters. According to the similar manner, benzofuro[2,3-b]pyridines, benzofuro[2,3-c]pyridines, and benzofuro[2,3-d]pyrimidines were synthesized in satisfactory yields. The intermediates were prepared smoothly by palladium catalyzed cross-coupling reaction of 3-, 6-, and 5-(2-iodophenoxy)-1,2,4-triazines with terminal acetylenes. The Diels-Alder reaction of 3-(2-phenylethynylphenoxy)-1,2,4-benzotriazine afforded 11-phenylbenzofuro[2,3-b]quinoline.
Published online:
■ Two New prenylaurones, Antiarones A and B, from the Root Bark of Antiaris toxicaria Lesch
Yoshio Hano, Pedro Mitsui, and Taro Nomura*
*Faculty of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan
Abstract
Two new prenylated aurones, antiarones A and B, were isolated from the root bark of Antiaris toxicaria Lesch. On the basis of spectral evidence, the structures of antiarones A and B were shown to be 1 and 2, respectively. These two compounds sre the first examples of prenylaurones.
Published online:
■ Synthesais of Corynanthe Alkaloids Corynantheine, Hirsuteine, and the Isositsirkines
Ichiya Ninomiya,* Takeaki Naito, Okiko Miyata,Tetsuro Shinada, Ekkehard Winterfeldt,* Ralf Freund, and Toshimasa Ishida
*Kobe Women’s College of Pharmacy, Motoyamakita, Higashinad, Kobe, Hyogo 658, Japan
Abstract
Total syntheses of corynanthe alkaloids including eight possible stereoisomers of isositsirikines along with corynantheine and hirsuteine according to two different approaches are described, thereby unambiguously solved the pending problems on the stereochemitry of these alkaloids.
Published online:
■ Synthesis and Crystal Structure of Hydrogen-bonded Long-Chain of 1:1-Methanol:1-[N-Methylpyridoxylidenium]-2-[21-pyridyl]hydrazine Iodide
Schelly Avramovici-Grisaru, Shmuel Cohen, and Shalom Sarel*
*Department of Medicinal Chemistry, The Hebrew University, P.O. Box 12065, Jerusalem 91120, Israel
Abstract
The synthesis and N-monomehtylation [(5)→(6a)] of 1-[pyridoxylidene]-2-[21-pyridyl]hydrazine (5) are herein described. The product, 1-[N-methylpyridoxylidenium]-2-21-pyridyl]hydrazine iodide (6a), on recrystallization from methanol yielded hydrogen-bonded long-chains of 1:1-methanol: (6a) of crystal structure (8) [Figure 2]. The reaction of (6a) with aqueous HClO4 afforded dimers of the corresponding diperchlorate of structure (6b) [Figure 1]. The formation of (8) is rationalized in terms of cooperative hydrogen-bonding, arising from the ability of the alcoholic OH group to function both as acceptor and donor. The dimeric crystal structure of (6b) is envisioned to arise from an alternative mode of H-bonding, namely, the "three- center" geometry, influenced by the ClO4 oxygen acceptors.
Published online:
■ Introduction of a New Concept: "d-Orbital Participation in Asyammetric Recognition" (DOPAR) for Use with CD Absorption Data of Dithiolane Derivatives
Tetsuichi Shibata,* Yoichi Iitaka, and Seiichi Inayama
*Pharmaceutical Institute, School of Medicine, Keio University, Shinanomachi 35, Shinjuku, Tokyo 160-0016, Japan
Abstract
An empirical correlation between the signs of circular dichroism (cd) absorption (at 237 and 252 nm) and the absolute configuration of two asymmetric carbons in a compound containing a dithiolane ring was elucidated by use of two types of molecular orbital calculation (MOC) (CNDO/2 and ab initio with STO-3G* set). These used the atom coordinate from X-ray crystallography of α-tetrahydro-L-α-santonin ethylene dithioacetal. The contributions of both the 3d-orbital of sulfur atom and the 2p-orbitals of asymmetric carbons in LUMO (excited state) in the results of MOC were shown to be relatively large. These results suggested that "d-orbital participation in asymmetric recognition" (DOPAR) would help explain the cd absorption data of the compound. The calculated/observed rations (c/o ratio) of two transition energy differences in the CD absorption were 2.7 CNDO/2 and 3.5 in the ab initio, respectively.
Published online:
■ A Total Synthesis of (+)-Geodiamolides A and B, the Novel Cyclodesiprptides
Yoshiro Hirai, Katsuyuki Yokota, Takao Yamzaki, and Takefumi Momose*
*Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
Abstract
Diastereo-controlled total synthesis of (+)-geodiamolides A (1) and B (2) has been accomplished via a prior synthesis of the tetrapropionate-derived fragment 7 and of the halogenated N-methyltyrosyltripeptide 6, the latter involving direct halogenation of the tripeptide 5, and subsequent coupling of both fragments followed by the trichlorobenzoyl chloride-mediated macrolactonization, respectively.
Published online:
■ Synthesis of Some Quinones of Relevance to a Synthetic Approach to Amphimedine. Crystal Structure Determination of 1-Methylpyrido[4,3-g]quinoline-4,5,10-trione 5-N,N-Diisopropylhydrazone
Premji Meghami, Owen S. Mills, and John A. Joule*
*Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, U.K.
Abstract
Tricyclic quinones are formed by the intramolecular strong acid catalyzed cycli-acylation of 2-(2-carboxyphenylcarbonyl)-1-methyl-4-pyridone and of 2-(4-methoxycarbonylpyridin-3-ylcarbonyl)-1-methyl-4-pyridone. Pyrido[4,3-g]quinoline-4,5,10-trione 6, thus produced, gives the 5-imine on reaction with ammonia; this imine reacts with lithium diisopropylamide to produce the 5-diisopropylhydrazone of 6.
Published online:
■ Organic Nitrosonium Salts. II. Stability Studies and Oxidations of Some Indole Derivatives
James M. Bobbitt, M. Cecile Flores Guttermuth, Zhenkun Ma, and Huitong Tang
*Department of Chemistry, U-60, Rm.151, 215 Glenbrok Rd., University of Connecticut, Storrs, CT 06269-3060, U.S.A.
Abstract
The stabilities of various salts of the 2,2,6,6-tetramethylpiperidine-1-oxonium ion were studied. 2,2,6,6-Tetramethylpiperidine-1-oxonium tetrafluoroborate was shown to react with 1,2,3,4-tetrahydrocarbazole (1-H-2,3,4,9-tetrahydrocarbazole) to give, in the presence of water, 4-keto-1,2,3,4-tetrahydrocarbazole in good yield. Under the same conditions, cyclopent[b]indole and cyclohept[b]indole gave the corresponding keto derivatives. In the absence of water, the oxidation of tetrahydrocarbazole gave a mixture of dimers, probably derived from the Diels-Alder self condensation of 1-H-2,3-dihydrocarbazole. The condensation is reversible and, in acid, the dimer mixture gives a salt of 1-H-2,3-dihydrocarbazole which can be reduced with sodium borohydride to give back tetrahydrocarbazole.
Published online:
■ Nucleotides, XXXIII: Synthesis and Properties of Inosinate Trimer I2’p5’I2’p5’I and Inosinate Tetramer I2’p5’I2’p5’I2’p5’I
Ramamurthy Charubana and Wolfgang Pfleiderer*
*Fakultät für Chemie, Universität Konstanz, Posttach 5560, D-7750 Konstantz, Germany
Abstract
The chemical synthesis of 2’-5’ inosinate trimer and tetramer was achieved by the phosphotriester method using the 2-(p-nitrophenyl)ethyl group for phosphate protection. The sugar hydroxyl groups have either been protected by the (tert-butyl)-dimethylsilyl or the benzoyl group. Final deprotection to the unblocked oligomers was achieved in over 85% yield. The inosinate oligomers show some antiviral activity against TMV.
Published online:
■ Metallation and Metal-assisted Bond Formation in π-Election Deficient Heterocycles
Kjell Undheim* and Tore Benneche
*Department of Chemistry, University of Oslo, P.O.Box 1033, Blindern, N-0315 Oslo, Norway
Abstract
Regiospecific C-C bond formation in electrophilic positions in π-electron deficient heteroarenes results from 1:1-adduct formation with organometallic reagents and dehydrogenation to heteroarenes. Cross-coupling between halogenoheteroarenes and organostannanes using Pd-catalysis introduces carbon substituents in a regio- or chemoselective manner; a Br- or I-substituent is replaced in any position, a Cl-substituent in an electrophilic position. Methods for the stannylation and palladation of pyrimidines are described. These metallopyrimidines are active in cross-couplong reactions. Pd(0,II)-catalysis has been used in the formation of the C-N bond by rearrangements of 2-propenyloxypyrimidines, and π-allylpalladium complexes in the direct N-alkylation. Preparation and reactions of pyrimidinylcerium dichlorides are discussed.
Published online:
■ Oligomeric Hydrolyzable Tannins, a New Class of Plant Polyphenols
Takuo Okuda,* Takashi Yoshida, and Tsutomu Hatano
*Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
Oligomeric hydrolyzable tannins belong to a newly developed field of tannin research. The isolation and structure determination of the first oligomer, agrimoniin, were presented in 1982, and since then more than sixty oligomers have been obtained from various plants by 1989. This review deals with these oligomers which were classified according to the biogenetical coupling modes between monomeric hydrolyzable tannins, and their botanical sources. Recent techniques for their isolation and structure elucidation, and the biological activities of the oligomers are also discussed.
Published online:
■ Interrelationships amongst peri-Condensed Thiophenes and Some Polycyclic Aromatics Hydrocarbons
LeRoy H. Klemm*
*Department of Chemistry, University of Oregon, Eugene, OR 97403, U.S.A.
Abstract
In the laboratory a peri-condensed thiophene (I) is commonly synthesized by inserting a sulfur bridging atom (from hydrogen sulfide or elemental sulfur) across the bay region of a polycyclic aromatic hydrocarbon precursor (II). This transformation may simulate the geochemical process whereby I forms in fossil fuels. Electrophilic substitution into I occurs ortho and/or para to the sulfur bridge and to the analogous positions in the isosteric hydrocarbon (III). The ultraviolet absorption spectra of I and III show similar shapes and characteristics. These interrelationships amongst I, II, and III are discussed.
Published online:
■ Recent Progress in Asysmmetric Synthesis of Pyrrolizidines
Wei-Min Dai, Yoshimitsu Nagao,* and Eiichi Fujita*
*Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
Abstract
Asymmetric syntheses of optically active pyrrolizidines are reviewed according to the chiral pools used.
Published online:
■ Cyclohepta[b][1,4]benzoxazine and Its Related Compounds. Some Novel Aspects in Heterocyclic Chemistry
Tetsuo Nozoe*
*Tokyo Research Laboratories, Kao Corporation, 2-1-3 Bunka, Sumida-ku, Tokyo 131-0044 Japan
Abstract
Chemistry of cyclohepta[b][1,4]benzoxazines and their S- and O-analogues as well as of the related compounds without annulated benzene ring is reviewed. Differing from usual, unreactive heterocycle-annulated tropylium compounds, title compounds are usually very reactive, especially towards 1,4-difunctional nucleophiles such as o-phenylenediamine, ethylenediamine and their S- and O-analogues. Reactivities towards alkali and oxidizing agents are comparatively described in view of the difference of the heteroatoms.
Published online:
■ The Thermal and Photochemical Behaviors of the Cyclomers of Ethylenebis- and Trimethylenebis(pyridinyl) Diradicals
Takashi Muramatsu, Yusaku Ikegami,* and Kaoru Hanaya
*Chemical Research Institute of Non-Aqueous Solutions, Tohoku University,. Katahira, Aoba-ku, Sendai 980-8577, Japan
Abstract
Pyridinyl diradicals of the type Py-(CH2)n-Py (Py = pyridinyl, n=2,3), which possess two pyridinyl monoradicals connected through a methylene chain, exist usually in equilibrium with the meso and dl cyclomers formed by intramolecular cyclization of the diradical. The equilibrium between diradical and cyclomers tends overwhelmingly toward the cyclomers in the dark and the cyclomers photodissociate to generate the diradical. This paper concentrates ou recent results on the preparation, structure, and thermal and photochemical behaviors of the diradicals and the cyclomers.