Regular Issue

Vol. 32, No. 8, 1991

21 data found. 1 - 21 listed
Communication | Regular issue | Vol 32, No. 8, 1991, pp. 1445 - 1450
Published online:
DOI: 10.3987/COM-91-5757
A New Method for Selective Protection of Two Hydroxyl Groups in Carbohydorates, Glycals in Particular

Cedric W. Holzapfel,* Johan J. Huyser, Thilo L. van der Merwe, and Fanie R. van Heerden*

*Department o f Chemistry and Biochemistry, Rand Afrikaans University, P.O. Box 524, Auckland Park, 2006, Johannesburg, South Africa


The regioselective conversion of selected carbohydrate derivatives into their allylic cyclic acetals was achieved by successive treatment with dibutyltin oxide, acrolein diacetate and catalytic amount of tetrakis(triphenylphosphine)palladium(0). Methods for removal of the new protecting group are discussed.

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Communication | Regular issue | Vol 32, No. 8, 1991, pp. 1451 - 1454
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DOI: 10.3987/COM-91-5764
The Practical Method for the Preparation of Iridoid Aglycons from Their Glycosides

Masahide Tanaka, Masaharu Kigawa, Hiroshi Mitsuhashi, and Takeshi Wakamatsu*

*Tsumura Reserach Institute for Biology and Chemistry (TRIBIC), Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan


The liberation of iridoid aglycons from their glycosides is achieved by the successive treatment with sodium metaperiodate, sodium borohydride, and hydrochloric acid in one pot operation. This simple and efficient method has advantages over the enzymatic hydrolysis from the preparative point of view.

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Communication | Regular issue | Vol 32, No. 8, 1991, pp. 1455 - 1460
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DOI: 10.3987/COM-91-5767
Nitrogen Bridgehead Compounds. Part 82. An Unexpected Ring Transformation of 6-Hydrozono-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-3-carboxylates

István Hermecz,* Ágnes Horváth, Tünde Erõs-Takácsy, and Benjamin Podányi

*Chinon Research Centre, Tó u.1-5, Budapest, H-1045, Hungary


Treatment of 9-hydrozono-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-3-carboxylates with the Vilsmeier-Haack reagent gave unsaturated 7-substituted 9-amino-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylates in a degenerate ring transformation, probably through ring opening via the N(5)-C(6) bond.

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Communication | Regular issue | Vol 32, No. 8, 1991, pp. 1461 - 1462
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DOI: 10.3987/COM-91-5774
Cimiciduphytine — A New Dimeric Indole Alkaloid from Haplophyton cimicidum (Apocynaceae)

Akinbo A. Adesomoju, M. V. Lakshmikantham, and Michael P. Cava*

*Department of Chemistry, University of Alabama, Box 870336, Tuscaloosa, Alabama 35478-0336, U.S.A.


Cimiciduphytine, a new dimeric indole alkaloid from Haplophyton cimicidum (Apocynaceae) has been assigned the aspidosperma-canthinone bisindole structure (1).

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Communication | Regular issue | Vol 32, No. 8, 1991, pp. 1463 - 1470
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DOI: 10.3987/COM-91-5776
Diels-Alder Reactions under Molecular Sieve Catalysis: Enhancement of Reactivity in Cyclization Reactions with N-Benzoylindole-2,3-quinodimethane to Functionalized Carbazoles

Ulf Pindur* and Manfred Haber

*Department of Chemistry and Pharmacy, Institute of Pharmacy, University of Mainz, Saarstraβe 21, D-55122 Mainz, Germany


In the presence of highly activated molecular sieves (4 Å), the Diels-Alder reactivity of in situ generated N-benzoylindole-2,3-quinodimethane is enhanced considerably. Reactions of this species with a variety of carbodienophiles give rise to novel functionalized and [b]annelated carbazole derivatives in a one-pot procedure.

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Communication | Regular issue | Vol 32, No. 8, 1991, pp. 1471 - 1482
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DOI: 10.3987/COM-91-5778
Secondary Metabolites by Chemical Screening 14. Transformation of Elaiophylin in subunits of Naturally Occurring Acid Ionophores: Synthesis, Anticoccidial Activity and Studies Concerning the Ionophoric Properties

Peter Hammann,* Gerhard Kretzschmar, Robert Klein, Wolfgang Raether, Maria Kajtár-Peredy, Achim Kröger, and Frank Ditzel

*Entwicklungsgruppe Synthese und SBU Antiinfektiva, Allgemeine Pharma Forschung, Hoechst AG, Postfach 800320, D-65926 Frankfurt, Main 80, Germany


The synthesis of the polyether subunits (8 - 11), starting from elaiophylin (1), as well as their biological properties, nmr spectra and conformational studies were described and discussed. Based upon the missing ability of potassium transport it was deduced that compounds (8 -11) were new laed structures concerning their anticoccidial activity.

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Communication | Regular issue | Vol 32, No. 8, 1991, pp. 1483 - 1486
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DOI: 10.3987/COM-91-5794
Total Synthesis of Euryfuran via Two Sequential Furan Ring Transfer Reaction

Ken Kanematsu* and Seizo Soejima

*Institute of Sythetic Organic Chemistry,Faculty of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan


Total synthesis of the marine natural product euryfuran (4) via two sequential furan ring transfer reaction is presented. Key elements of the reaction pathway include as follows: 1) the preparation of propargyl ethers (5c), (10b), and (17c), and its transformation to allylic alcohols (6), (11) and (18), 2) introduction of the angular alkyl group via [3,3] sigmatropic rearrangement.

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Communication | Regular issue | Vol 32, No. 8, 1991, pp. 1487 - 1490
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DOI: 10.3987/COM-91-5806
An Efficient and Convenient Route to Spiro-fused γ-Butyro- and δ-Valerolactones

Fusao Kido,* Toshiya Abiko, Abul B. Kazi, Michiharu Kato, and Akira Yoshikoshi

*Institute for Chemical Reaction Science, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan


Treatment of the α-diazomalonates (5a-c) of 2-[(2-phenylthiomethyl)-1-cycloalkenyl]ethanols with rhodium acetate led to the [2,3] sigmatropic rearrangement of the cyclic allylsulfonium ylides (6a-c) to give the spiro-fused δ-valerolactones (7a-c) in excellent yields. Similarly, the spiro-fused γ-butyrolactone (10) was prepared starting with the α-diazomalonate (9) of [(2-phenylthiomethyl)-1-cyclohexenyl]methanol analog.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1491 - 1498
Published online:
DOI: 10.3987/COM-90-5550
Thermal and Photochemical Investigation of the Reaction of Indole-2,3-dione with Pyrazolone

Krishna C. Joshi, Ramchand T. Pardasani,* Anshu Dandia, and Sunita Bhagat (nee Baweja)

*Department of Chemistry, University of Rajasthan, Jaipur 302 004, India


Some novel reactions of indole-2,3-dione (1) with pyrazolone (2) under thermal and photochemical conditions have been studied. Under thermal conditions, a variety of novel compounds viz. 1,3-dihydro-3-[(3’-methyl-5’-oxo-1’-phenylpyrazolidene)]-2H-indol-2-one (3), 3,5-dimethyl-1,7-diphenylspiro[dipyrazolo(3,4-b;4,3-e)pyran-4(4H),3’(3H)indol]-2’[1’H]-one (4), and 5-fluoro-3,3-bis(3’-methyl-5’-oxo-1’-phenylpyrazol-4’-yl)indol-2[1H]-one (5) were obtained. The photochemical irradiation afforded other compounds like 3-methyl-4,5-dioxo-1-phenylpyrazolo[3,4-b]benzapine (6), and 3-[2’-(1’’-carboxy-2’’oxoethyl)-4’-fluorophenyl]-5-fluoroindol-2-one (7) in addition to thermal products (3) and (4) or (5).

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1499 - 1504
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DOI: 10.3987/COM-90-5578
Synthesis of Chiral Indolizines as Bicyclic Ergoline Analogues

Peter Gmeiner

*Institut für Pharmazie und Lebensmittelchemie, Ludwig-Maximilins-Universität, Sophienstraße 10, 8000 München 2, Germany


An efficient synthesis of the enantiomerically pure aminoindolizine (3) by a triflic anhydride assisted cyclization of the 1,3-amino alcohol (6) is reported. 6 can be readily derived from L-asparagine (4) via the O-activated β-homoserine equivalent (7).

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1505 - 1515
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DOI: 10.3987/COM-90-5595
Synthesis and Beta-Lactamase Inhibitory Activity of 2,2-Bis(monosubstituted) Methylpenicillin Sulfones

Samarendra N. Maiti,* Paul Spevak, Rebecca Wong, Narender A. V. Reddy, Ronald G. Micetich, and Kazuo Ogawa

*SynPhar Laboratories Inc., 4290-91A Street, Edmonton, Alberta, T6E 5V2, Canada


A series of 2,2-bis(monosubstituted) methylpenicillin sulfones were prepared from 6,6-dibromopenicillanate by a double sulfoxide rearrangement. β-Lactamase inhibitory activity of 2,2-bis(chloromethyl)penicillanic acid sulfone was studied and its activity was compared with YTR-830.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1517 - 1526
Published online:
DOI: 10.3987/COM-91-5726
Heterocyclization Reactions of Chlorosulfonyl Isocyanate with Ethyl 3-Oxo-2-(arylhydrazono)butanoates

Joseph Daniel and Durga Nath Dhar*

*Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India


Reaction of chlorosulfonyl isocyanate with ethyl 3-oxo-2-(arylhydrazono)butanoates (1a-i) gave thiadiazolotriazinediones (3a-i) and thiatriazinothioxapyridazines (6a-i). Here a 1:2 reacton of the butanoate and CSI followed by cyclization is postulated.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1527 - 1535
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DOI: 10.3987/COM-91-5740
Stereoselectivity in the Preparation of Indolo[2,3-a]quinolizidine Nb-Metho-Salts

Mauri Lounasmaa* and Tarja Tamminen

*Laboratory for Organic and Bioorganic Chemistry, Technical University of Helsinki, P.O. Box 6100, FIN-02150 HUT, Espoo 15, Finland


Stereoselective preparation of indolo[2,3-a]quinolizidine Nb-metho-salts has been studied. Although the Nb-methylation is a kinetically controlled reaction (preferential methylation at the conformation where the Nb-atom is least hindered), isomeric mixtures were obtained in all cases where the trans-quinolizidine ring juncture (conformation a) of the starting conpounds was strongly favoured. This indicates a partial conformational control of the reaction. BOC-protected compounds yielded C(12b)H-Nb-CH3 cis-products only. Since this stereochemistry is maintained in deprotection, an attractive approach is offered for the stereoselective preparation of the cis-isomers.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1537 - 1545
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DOI: 10.3987/COM-91-5751
An Unusual Condensation of Pyrimidinones: Synthesis of Bipyrimidinones and Bipyrimidinylmethane

Maurizio Botta,* Raffaele Saladino, Augusto Gambacorta, and Rosario Nicoletti*

*Dipartimento Farmaco Chimico Tecnologico, Banchi di Sotto 55, Università degli Studi, 53100 Siena, Italy


An unusual condensation of pyrimidinones (2), (3), and (12) in the presence of lithiated furan derivatives or LiHMDS lead to the formation of 7, 8, and 13. In the case of the self condensation of 3, a novel acyloin reaction is invoked to explain the formation of product (8) where the substrate acts as the catalyst in the reaction.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1547 - 1557
Published online:
DOI: 10.3987/COM-91-5755
Heterocyclic Rearrangements. A Semiempirical Study of a Degenerate Rearrangement in the 1,2,4-Oxadiazole Series

Gianfranco La Manna, Silvestre Buscemi, Vincenzo Frenna, Nicolò Vivona,* and Domenico Spinelli

*Dipartimento di Chimica Organica, Università digli Studi di Palermo, Via Archirafi 20 90123 Palermo, Italy


A semiempirical approach to the rearrangement of the 3-acetylamino-5-methyl-1,2,4-oxadiazole is reported. Quantum mechanical calculations at the MNDO and AM1 level have been carried out for the anionic form of the acetylaminooxadiazole and for the transition state. The theoretical value of activation energy for the degenerate process has been compared with the experimental free energy of activation previously obtained by the dynamic 1H-nmr. The calculations have been also extended to the different conformers of the anionic acetylamino moiety and to the conformational processes. Furthermore, a quasi-degenerate rearrangement for the 3-trideuterioacetylamino-5-methyl-1,2,4-oxadiazole has been pointed out by nmr technique, and the calculated free energy of activation confirmed the expected lower reactivity of the neutral species with respect to the anionic one.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1559 - 1561
Published online:
DOI: 10.3987/COM-91-5763
A Novel Dithiophthalide Synthesis

Peter N. Nugara, Nai-Zhong Huang, M. V. Lakshmikantham, and Michael P. Cava*

*Department of Chemistry, University of Alabama, Box 870336, Tuscaloosa, Alabama 35478-0336, U.S.A.


Thionation of o-phthalaldehyde and naphthalene-2,3-dicarboxaldehyde with Lawesson’s reagent led to the efficient formation of dithiophthalide and 2,3-dithionaphthalide respectively. Dithioaldehydes are presumed intermediates in these conversions.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1563 - 1570
Published online:
DOI: 10.3987/COM-91-5771
Retro-Diels-Alder Fragmentation of Coumaronochromones and Complete Assignments of 13C Nmr Data for Lupinalbin A and Ayamenin B

Fujinori Hanawa, Satoshi Tahara,** and Junya Mizutani*

*Mizutani Plant Ecochemicals Project, Research Development Corporation of Japan, 3-3-1 Megumino Kita, Eniwa-shi, Hokkaido 061-13, Janan


A new retro-Diels-Alder fragmentation pathway for coumaronochromones was found in ei ms, and complete assignments of 13C nmr data for simple coumaronochromones (lupinalbin A and Ayamenin B) were presented.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1571 - 1578
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DOI: 10.3987/COM-91-5777
Oxidative Nitration and Bromination of Berbin-8-one

Jean-François Stambach* and Louis Jung

*Laboratoire de Chimie Thérapeutique, U.F.R. des Sciences Pharmaceutiques, Université Louis Pasteur, 74, route du Rhin, BP 24, 67401 ILLKIRCH Cedex, France


In presence of two equivalents of nitric acid berbin-8-one (1) could be oxidized and nitrated to give 13-nitro-13,13a-dehydroberbin-8-one (2) in good yield. In the same way berbin-8-one (1) was made to react with N-bromosuccinimide to afford the 13-bromo analogue (3). The mechanism of the nitrative oxidation was studied. This oxidation is initiated by nitrogen dioxide from nitrous fumes included in the nitric acid. The oxidative nitration is accelerated by increasing the acidity or temperature of the medium. A radical mechanism which involves the 13,13a-dehydro-berbin-8-one (9) as intermediate of the reaction is postulated and discussed. The potential of this synthetic route was investigated.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1579 - 1586
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DOI: 10.3987/COM-91-5788
Reactions of 3-Substituted Quinoline 1-Oxides with Acylating Agents

Yutaka Miura,* Sakae Takaku, Yoshiharu Nawata, and Masatomo Hamana

*Exploratory Laboratories, Chugai Pharmaceutical Company, Ltd., 135, 1-Chome Komakado, Gotemba, Shizuoka 412-8513, Japan


Reactions of 3-fluoro- (1a), 3-bromo- (1b), 3-methyl- (1c), 3-methoxy- (1d) and 3-acetamidoquinoline 1-oxides (1e) with acylating agents (POCl3, Ac2O, TsCl and PhCOCl) were examined (Table). While only 2-substituted quinolines were obtained from 1a and 1b, fair amounts of 4-substituted products were formed in reactions of 1d, the sole formation of the 4-acetoxyquinoline (6) with Ac2O being the most significant result. 2-Chloroquinolines, 4-chloroquinolines and 2-tosyloxyquinolines were formed (and sometimes predominate) in addition to 2-quinolinones in reactions with TsCl.

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Paper | Regular issue | Vol 32, No. 8, 1991, pp. 1587 - 1591
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DOI: 10.3987/COM-91-5802
A Facile Synthesis of (S)-O-Benzylglycidol

Seiichi Takano,* Takumichi Sugihara, Takashi Kamikubo, and Kunio Ogasawara

*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan


A facile synthesis of (S)-O-benzylglycidol has been developed starting from (R)-1-O-benzylglycerol by sequential monohalogenation and cyclization.

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Review | Regular issue | Vol 32, No. 8, 1991, pp. 1593 - 1638
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DOI: 10.3987/REV-91-427
Some Aspects of the Chemistry and Biological Activity of Artemisinin and Related Antimalarials

Syed S. Zaman and Ram P. Sharma*

*Division of Natural Products Chemistry, Regional Reseach Labratory (CSIR), Jorhat-6, Assam, India


Developments taken place in the field of artemisinin and related antimalarials during the last five years have been reviewed.

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21 data found. 1 - 21 listed