Regular Issue

Vol. 29, No. 12, 1989

21 data found. 1 - 21 listed
Communication | Regular issue | Vol 29, No. 12, 1989, pp. 2245 - 2248
Published online:
DOI: 10.3987/COM-88-S17-1
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


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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Communication | Regular issue | Vol 29, No. 12, 1989, pp. 2249 - 2252
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DOI: 10.3987/COM-89-5155
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


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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Communication | Regular issue | Vol 29, No. 12, 1989, pp. 2253 - 2256
Published online:
DOI: 10.3987/COM-89-5156
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


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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Communication | Regular issue | Vol 29, No. 12, 1989, pp. 2257 - 2260
Published online:
DOI: 10.3987/COM-89-5168
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.


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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Communication | Regular issue | Vol 29, No. 12, 1989, pp. 2261 - 2265
Published online:
DOI: 10.3987/COM-89-5181
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


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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Communication | Regular issue | Vol 29, No. 12, 1989, pp. 2267 - 2271
Published online:
DOI: 10.3987/COM-89-5199
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


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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Communication | Regular issue | Vol 29, No. 12, 1989, pp. 2273 - 2277
Published online:
DOI: 10.3987/COM-89-5203
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.


The synthesis of (+)-homodeoxoartemisinin, 3, was achieved from artemisinic acid, 4, in eight steps.

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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2279 - 2285
Published online:
DOI: 10.3987/COM-89-5038
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


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2287 - 2296
Published online:
DOI: 10.3987/COM-89-5055
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


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2297 - 2300
Published online:
DOI: 10.3987/COM-89-5087
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


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2301 - 2316
Published online:
DOI: 10.3987/COM-89-5093
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


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2317 - 2326
Published online:
DOI: 10.3987/COM-89-5100
Five New Diterpenoids from Aconitum dolichorhynchum

Liang Huilling and Chen Siying*

*Academica Sinica, Kunming Institute of Botany, Heilongtan, Kunming, Yunnan, China


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2327 - 2334
Published online:
DOI: 10.3987/COM-89-5103
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.


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2335 - 2343
Published online:
DOI: 10.3987/COM-89-5115
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


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2345 - 2351
Published online:
DOI: 10.3987/COM-89-5122
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.


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2353 - 2359
Published online:
DOI: 10.3987/COM-89-5132
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


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2361 - 2367
Published online:
DOI: 10.3987/COM-89-5162
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


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2369 - 2377
Published online:
DOI: 10.3987/COM-89-5172
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


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2379 - 2390
Published online:
DOI: 10.3987/COM-89-5189
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


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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2391 - 2397
Published online:
DOI: 10.3987/COM-89-5215
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.


(±)-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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Paper | Regular issue | Vol 29, No. 12, 1989, pp. 2399 - 2402
Published online:
DOI: 10.3987/COM-89-5241
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.


The basicities of 7,8-dithydrocyclopenta[ij]isoquinoline (3) and a series of related compounds were determined spectropholometrically.

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21 data found. 1 - 21 listed