HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Regular Issue
Vol. 29, No. 12, 1989
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■ The 1,3-Dipolar Cycloaddition of 3-Methyl-5-phenylisoxazoline N-Oxides
Yuan L. Chow,* Y. Yuan Shu, Bert H. Bakker, and K. Somasekharen Pillay
*Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, B. C. V5A 1S6, Canada
Abstract
The title isoxazoline N-oxide 3 underwent 1,3-dipolar cycloaddition with a number of electron deficient olefins regiospecifically to give isoxazolizidines 4 All four possible geometric approaches of addenda leading to successful cycloadditions occurred to give mixtures of products. A pressure at 1~2 KBar did accelerate the rate of the 1,3-dipolar cycloadditions significantly without improving the selectivity of geometrical orientations of approaches: the poor selectivity was ascribed to the lack of ground state molecular association in solution.
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■ Studies on as-Triazine Derivatives XIII. A Facile Synthesis of Fusaric Acid from Thienyl-as-triazine Derivatives
Mataichi Sagi, Masaki Amano, Shoetsu Konno, and Hiroshi Yamanaka*
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
Reverse electron-demand Diels-Alder reaction of ethyl 6-(2-thienyl)-1,2,4-triazine-3-carboxylate with norbornadiene in boiling p-xylene followed by the elimination of cyclopentadiene (retro Diels-Alder reaction) gave 5-(2-thienyl)pyridine-2-carboxylate. Desulfurizatian of the thienylpyridine with Raney nickel and subsequent saponification afforded fusaric acid (5-butylpyridine-2-carboxylic acid).
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■ Studies on as-Triazine Derivatives XIV. Synthesis and Reverse Electron-demand Diels-Alder Reaction of Ethyl 5,8-Dichloro-1,2,4-benzotriazine-3-carboxylate
Mataichi Sagi, Osamu Sato, Shoetsu Konno, and Hiroshi Yamanaka*
*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan
Abstract
Ethyl 5,6,7,8-tetrahydro-1,2,4-benzotriazine-3-carboxylate was treated with sulfuryl chloride to give ethyl 5,5,8,8-tetrachloro-5,6,7,8-tetrahydro-1,2,4-benzotriazine-3-carboxylate. Following dehydrochlorination of the tetrachloro compound with triethylamine afforded ethyl 5,8-dichloro-1,2,4-benzotriazine-3-carboxylate. The dichloro-1,2,4-benzotriazine derivative was heated with norbornadiene in p-cymene to give ethyl 5,8-dichloroquinoline-2-carboxylate. Intramolecular Diels-Alder reaction of the dichloro-1,2,4-benzotriazine derivative was also investigated.
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■ Unambiguous Carbon-13 NMR Assignments of Some Biologically Active Protoberberine Alkaloids
Raouf A. Hussain, Jinwoong Kim, Christpher W. W. Beecher, and A. Douglas Kinghorn*
*Program for Collaborative Research in the Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, 833 South Wood St., Chicago, IL 60612-7231, U.S.A.
Abstract
Unambiguous proton and carbon-13 nmr chemical shifts of the protoberberine quaternary alkaloids palmatine (1) and jatrorrhizine (2) theilr, tetrahydro derivatives (3,4), and tetrahydroberberine (5) have been determined through the use of 2D, CSCM 1D and selective INEPT nmr techniques.
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■ Palladium Assisted Synthesis of a Thromboxane B2 Precursor
Mathys M. Basson, Cedric W. Holzapfel, and Gerhard H. Verdoorn*
*Department o f Chemistry and Biochemistry, Rand Afrikaans University, P.O. Box 524, Auckland Park, 2006, Johannesburg, South Africa
Abstract
The stereospecific synthesis of a bicyclic precursor for thromboxane B2, using palladium mediated transformations of tri-O-acetyl-D-glucal, is described.
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■ Woodfordins A, B, and C, Dimeric Hydrolyzable Tannins from Woodfordia fruticosa Flowers
Takashi Yoshida, Tong Chou, Aya Nitta, and Takuo Okuda*
*Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
Three new dimeric hydrolyzable tannins, woodfordins A, B, and C, along with six known hydrolyzable tannins including oenothein B, a dimer which exhibited remarkable host-mediated antitumor activity, were isolated from an Indonesian crude drug, “Sidowayah” [dried flowers of Woodfordia fruticosa (L.) Kurz (Lythraceae)]. The structures of new dimers were elucidated by chemical and spectral methods.
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■ Stereospecific Synthesis of (+)-Homodeoxoartemisinin
Daniel A. Bustos, Mankil Jung,* Hala N. ElSohly, and James D. Mcchesney
*Department of Pharmacology, School of Pharmacy, University of Mississippi, University, Mississippi 38677, U.S.A.
Abstract
The synthesis of (+)-homodeoxoartemisinin, 3, was achieved from artemisinic acid, 4, in eight steps.
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■ Structure and Reactions of 6-Oxo-1,2,4-triazines
Mohga M. Eid, Sayed A. Abdel-Hady, and Hosny A. W. Ali
*Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt
Abstract
The strucrure of 6-oxo-1,2,4-triazine derivatives obtained by cyclization of α-acylaminoacryloylhydrazides is now confirmed spectroscopically and through their chemical transformarion to the corresponding 6-thioxo and 6-chloro delivatives and reactions.
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■ Sesquiterpene Esters from Maytenus chubutensis
Antonio G. González, Mercedes P. Nufíez, Angel G. Ravelo, Javier G. Luis, Ignacio A. Jiménez, Jesús T. Vázquez, and Orlando M. Mufíoz
*Instituto de Productos Naturales y Agrobiologia de Canrias, C. S. I. C./ Unversidad de La Laguna, P.O. Box 195, 38206- La Laguna, Tenerife, Spain
Abstract
From the aerial part of Maytenus chubutensis Speg. six new dihydro-β-agarofuran skeleton sesquiterpenes were isolated and identified by spectroscopy, chemical reactions and selective hydrolysis. Absolute configurations were established by cd methods.
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■ A New Pyranoxanthone and Flavonoids from Hypericum canariensis
M. Luz Cardona, Isabel Fernández, José R. Pedro,* and Angel Serrano
*Department of Organic Chemistry, Faculty of Chemistry, Valencia University, 46100-Burjassot, Valencia, Spain
Abstract
Hypericum canariensis contains quercetin, hyperin, I3,II8-biapigenin and a new compound, hypericanarin B, which is identified as 8-hydroxy-3,3-dimethylpyrano [3,2-a] xanthen-12 (3H)-one on the basis of spectroscopic evidence.
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■ 2-Methylthio-1,3,4-thiadiazolium Cations as Useful Precursors for the Preparation of 2-Amino-1,3,4-thiadizole Derivatives and as Dehydrating Reagents of Aldoximes
Pedro Molina,* Alberto Tearraga, and Arturo Espinosa
*Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, E-30071, Murcia, Spain
Abstract
The 2-methylthio-1,3,4-thiadiazolium perchlorates 1 react with primary amines, hydrazines, hydrazones and hydrazides to give the 2-amino-1,3,4-thiadiazole derivatives 2, 3 and 4 respectively. Similarly, 1 with diamino compounds leads to the corresponding bi-heterocycles 11, 12 and 13. The reaction of 1 with aldoximes leads directly to 1,3,4-thiadiazol-2-ones 16 and the corresponding nitriles in high yields.
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■ Five New Diterpenoids from Aconitum dolichorhynchum
Liang Huilling and Chen Siying*
*Academica Sinica, Kunming Institute of Botany, Heilongtan, Kunming, Yunnan, China
Abstract
From the root extracts of Aconitum dolichorhynchum Wang var. subglabratum T. L. Ming, we have isolated five new minor alkaloids: dolichotine A (I), dolichotine B (II), dolichotine C (III), dolichotine D (IV) and dolichotine E (V), besides yunaconitine (VI), 8-deacetylyunaconitine (VII), crassicauline A (VIII), talatisamine (IX), columbidine (X) and cammaconine (XI). The structures of these alkaloide were determined with the aid of spectral data and correlation with compounds of established structures. The structure of dolichotine C was confimed by syntheeis from talatisamine and partial hydrolysis. All the new alkaloids are characteristic of aromatic acid ester or palmitic acid ester substituted at C8 of C19-diterpenoid alkaloids.
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■ The Synthesis of Novel N-Pyrisyl-3,6-dihydro-1,2-oxazines
Henryk Labaziewicz,* Karl R. Lindfors, and Tammy H. Kejonen
*Malcom H. Filson Laboratories, Department of Chemistry, Central Michigan University, Mt. Pleaasant, MI 48859, U.S.A.
Abstract
A series of fifteen new N-pyridyl-3,6-dihydro-1,2-oxazines has been prepared from 1,3-butadienes and nitrosopyridines. 2-Aminopyridine, 2-amino-4-methyipyridine and 2-amino-6-methylpyridine were converted via nitroso compounds to 1,2-oxazines. The transformation was carried out sequentiaily in one vessel without isolation of either the intermediate suifilimine or the nitroso compound.
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■ Synthesis of 2,2-Dimethyl-4-methoxychromans
Albert Lévai and Tibor Timár
*Department of Organic Chemistry, Lajos Kossuth University, P.O.Box 20, H-4010 Debrecen, Hungary
Abstract
2,2-Dimethyl-4-methoxychromans have been synthesized by the reduction of 2,2-dimethyl-4-chromanones with NaBH4 followed by treatment with hydrochloric acid in methanol solution.
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■ The Skraup Reaction of 3,4-Dihydroanilines
Richard A. Blatchly, Michael A. Greeley, and J. Hodge Markgraf*
*Department of Chemistry, Williams College, 47 Lab Campus Drive, Williamstown, MA 01267, U.S.A.
Abstract
Six 3,4-dithaloanilines (1) were converted by the sulfo-mix variation of the Skrap reaction to mixtures of 5,6- and 6,7-dihaloquinolines, 2 and 3 respectively. Inductive effects were the dominant influence on the course of cyclization: the more highly electronwithdrawing the substituents of 1, the greater was the proportion of 3. Steric effects were absent.
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■ Some Physicochemical Parameters of 11H-Indole[3,2-c]quinoline
Go Mei Lin and Ngiam Tong Lan*
*Department of Pharmacy, National University of Singapore, Lower Kent Ridge Road, 119260, Singapore
Abstract
The hydrophobicity (log P), pKa and limiting solubility of 3-chloro-8-methoxy-11H-indolo[3,2-c]quinoline (I), a representative 11H-indolo[3,2-c]quinoline, were determined. A significant difference was observed between the basicity of I and its non-cyclized analogue, 7-chloro-4-N-(p-methoxyphenyl)aminoquinolie (II). I was found to be a weaker base (pKa 3.99) than II (pKa 7.59), which suggested that the indolo N, unlike the 4-amino group of II, did not affect the basicity oi the quinolyl N. I was also much less hydrophobic and more water soluble than II, which could only be attributed partly to a reduction of surface area on ring formation. Based on the present determinations, the unique hydrophobicity of the 11H-indolo[3,2-c]quinoline ring system was calculated to have a log P value of 2.22.
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■ Reaction of Benzoquinones with Cyclic Amines; 1H- and 13C-Nmr Spectra of Amine-adducts
Mitsuo Akiba,* Keiko Nagaoka, Masazumi Takigawa, and Toyozo Takada
*School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
Abstract
Reaction of unsymmetrical 1,4-benzoquinone with cyclic amines afforded a mixture of amine-adducts. Using dibromoquinone as the substrate, monoamine adduct was obtained regioselectively. Regiochemistry was determined by 1H- and 13C-nmr spectroscopic analyses.
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■ New Applications of Westphal Condensation. Synthesis of New [2.3.3]Cyclazinones
Joaquin Pastor, M. Paz Matia, Jose L. García Navío, Juan J. Vaquero, and Jullio Alvarez-Builla*
*Departamento de Química Orgánica, Universidad de Alcalá de Henares, 28871 Alcalá de Henares (Madrid), Spain
Abstract
Two different types of [2.3.3]cyclazinone isomers were obtained by methods based on the Westphal condensation. 2,6-Dialkylpyridinium salts were condensed with 1,2-acenaphtenequinone to produce [2.3.3]cyclazin-1-one derivatives. By a similar process, a quinolizinium-1-olate was prepared, which was cyclized with DMAD yielding a [2.3.3]cyclazin-6-one derivative.
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■ Revised Structures of Broussoflavonols C and D, and the Structure of Broussoflavonol E
Toshio Fukai and Taro Nomura*
*Faculty of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan
Abstract
The structures of broussoflavonols C and D isolated from the root bark of Broussonetia papyrifera (L.) VENT. (Japanese name “Kazinoki,” Moraceae) were revised from the structures (1’) and (2’) to 1 and 2, respectively, on the basis of spectral data. Broussoflavonol E (3) was isolated from the root bark of Broussanetia sp. (Japanese name “Kozo,” a cultivated variety of paper mulberry, Broussonetia papyrifera (L.) VENT. x B. kazinoki SIEB.). The structure of broussoflavonol E was shown to be 3 on the basis of spectral evidence.
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■ A Short Synthesis of (±)-2,5-Epoxy-6(E),8(E)-megastigmadiene
Michael P. DiFazio, William A. Wallace, and Albert T. Sneden*
*Department of Chemistry, Box 2006, Virginia Commonwealth University, Richmond, Virginia 23284-2006, U.S.A.
Abstract
(±)-2,5-Epoxy-6(E),8(E)-megastigmadiene 1 was synthesized in seven steps and 27% overall yield from 2-methylfuran. The Diels-Alder reaction of 2-methylfuran with 2-chloroacrylonitrile gave 2-chloro-2-cyano-1-methyl-7-oxabicyclo[2.2.1]hept-5-ene 5a as the major regioisomer. Hydrogenation of 5a followed by hydrolysis and alkylafion provided the key intermediate, 1,3,3-trimethyl-7-oxabicyclo[2.2.1]heptan-2-one 4. The conjugated diene sidechain was then introduced via a Grignard reaction followed by formation and subsequent decomposition of the phenylurethane derivative 10 to give 1 and its 6(Z) isomer 2.
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■ Strained Heterocycles Systems. 17. Basicities of Selected Isoquinolines
J. Hodge Markgraf,* Thomas Mueller, and Christopher R. Myers
*Department of Chemistry, Williams College, 47 Lab Campus Drive, Williamstown, MA 01267, U.S.A.
Abstract
The basicities of 7,8-dithydrocyclopenta[ij]isoquinoline (3) and a series of related compounds were determined spectropholometrically.