Regular Issue

Vol. 51, No. 4, 1999

18 data found. 1 - 18 listed
Communication | Regular issue | Vol 51, No. 4, 1999, pp. 721 - 726
Published online:
DOI: 10.3987/COM-98-8455
Cross Coupling Strategies towards the Synthesis of the Streptonigrin CD Moiety

Renier Crous, Catherine Dwyer, and Cedric W. Holzapfel*

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


An efficient route to an appropriate model of the streptonigrin 4-phenylpyridine CD moiety is reported. 4-Chloro-3-nitropyridine was found to be the key precursor and its reactivity in cross coupling reactions was further investigated.

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Communication | Regular issue | Vol 51, No. 4, 1999, pp. 727 - 731
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DOI: 10.3987/COM-98-8458
Synthesis of 5-Hydroxyoxaindan-2-ones and Indol-5-ols from 1,4-Cyclohexanedione

Yutaka Ozaki,* Zhe-Shan Quan, Kyouko Watabe, and Sang-Won Kim*

*Faculty of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japana


1,4-Cyclohexanedione reacted with 2-oxocarboxylic acids to give 5-hydroxyoxaindan-2-ones including hornogentisic lactone in one pot. The obtained aromatic compounds were transformed into indol-5-ols in a few steps. The sequential reactions showed a significance of 1,4-cyclohexanedione as a starting material in aromatic synthesis and an alternative access to the indol-5-ols.

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Communication | Regular issue | Vol 51, No. 4, 1999, pp. 733 - 736
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DOI: 10.3987/COM-98-8468
5-exo,5-exo Cascade Cyclizations of Halo-Olefins by Environmentally Friendly Reaction Using Indirect Electrolysis

Akira Katsumata, Kiyosei Takasu, and Masataka Ihara*

*Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai 980-5878, Japan


[Ni(cyclam)](ClO4)2 or vitamin B12a-mediated electroreduction of the 1-bromo-5-ene-10-yne (4) and the l-bromo-5,10-diene (6) gave bicyclic five-membered ring compounds in a highly regioselective manner by 5-exo,5-exo cascade radical cyclizations.

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Paper | Regular issue | Vol 51, No. 4, 1999, pp. 737 - 750
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DOI: 10.3987/COM-98-8431
General Synthetic Pathway to Oxygenated 3-Methylbenz[g]isoquinoline-5,10-diones

A. Paul Krapcho* and David J. Waterhouse

*Department of Chemistry, Cook Physical Science Building, The University of Vermont, Burlington, Vermont 05405-0125, U.S.A.


The synthesis of naturally occurring dioxygenated and trioxygenated 3-methylbenz[g]isoquinoline-5,10-diones has been accomplished. The critical step involved regioselective additions of di- or trifluorobenzylzinc bromides to activated methyl 6-methylnicotinate. Aromatizations of the resultant dihydropyridines followed by hydrolysis led to the corresponding benzylpyridinecarboxylic acids which on annulative-oxidations led to the respective difluoro- or trifluorobenz[g]isoquinoline-5,10-diones. Displacements of fluorides by methoxide led to the di- or trimethoxy analogues which on selective demethylations led to bostrycoidin, 8-O-methyl-bostrycoidin, tolypocladin, 5-deoxybostrycoidin or 5-deoxy-6-O-methyl-bostrycoidin. The synthesis of isobostrycoidin and isotolypocladin has also been accomplished.

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Paper | Regular issue | Vol 51, No. 4, 1999, pp. 751 - 762
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DOI: 10.3987/COM-98-8439
Synthesis and Mesogenic Properties of Schiff Bases Derived from Aminopyrazoles

Rosa María Claramunt,* Isabel Forfar, Pilar Cabildo, Javier Lafuente, Joaquín Barberá,* Raquel Giménez, and José Elguero

*Centro de Química Orgánica 'Manuel Lora-Tamayo', Instituto de Química Médica, C. S. I. C., Calle Juan de Cierva, 3, E-28006 Madrid, Spain


Fifteen azomethineimines derived from C-aminopyrazoles and aromatic aldehydes have been prepared and fully characterized (IR, MS, 1H and 13C NMR in solution and 13C CPMAS NMR). The benzaldehyde bearing at position 4 n-decyloxy or a n-butyloxycarbonylethyloxy substituents and at position 2 a hydrogen or a hydroxy substituent have been tested for mesogenic properties. Only 5 [1H-4-(4-n-decyloxy-2-hydroxybenzylideneaminopyrazole)] presents a mesogenic behaviour (smectic A) on cooling.

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Paper | Regular issue | Vol 51, No. 4, 1999, pp. 763 - 783
Published online:
DOI: 10.3987/COM-98-8443
Reduction of 4H-Imidazoles — Synthesis and Reactivity of 4,5-Diaminoimidazoles Bearing a Tetraaminoethene Substructure

Jens Atzrodt, Rainer Beckert,* and Helmar Görls

*Institut für Organische Chemie und Makromolekulare Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 10, D-07743 Jena, Germany


The 4H-imidazoles (1) caii be reduced after deprotonation to the trianion (4) by two consecutive single electron transfer reactions. Subsequent quenching by simple electrophiles constitutes a convenient route to the title substances of type (5). The unexpected regioselectivity towards bielectrophilic building blocks facilitates tile synthesis of highly substituted heterospiranes (7) and the imidazo crown ethers (8). The trianion (4) reacted with two molecules of CS2 at the exocyclic nitrogen atoms exclusively to afford after quenching the dithiocarbamates (10) and the cyclic thiuram suifides (11). The new imidazole derivatives of type (5) showed only slight electron donor properties. An electrophilic attack led with preference to a quarternization of the unsubstituted ring nitrogen atom of 5, as shown by the synthesis of compound (13). A similar behaviour was observed by treatment of 5 with acetylenedicarboxylate. in which the red 1:2 adduct (14) was formed in yields up to 76 %.

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Paper | Regular issue | Vol 51, No. 4, 1999, pp. 785 - 794
Published online:
DOI: 10.3987/COM-98-8444
Direct Introduction of Nucleophilic Carbanions to the g-Position of Na-Boc-protected Nb-Tryptophylpyridinium Salts without Electron Withdrawing Substituents at the β-Position

Pirjo Hanhinen, Tiina Putkonen, and Mauri Lounasmaa*

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


Addition of dimethyl malonate anion to the y-position of Na-BOC protected Nb-tryptophyIpyridinium salts without electron withdrawing substituents at the β-position of the pyridinium ring was examined. The method permits direct access to the indoloquinolizidine skeleton present in several indole alkaloids.

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Paper | Regular issue | Vol 51, No. 4, 1999, pp. 795 - 802
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DOI: 10.3987/COM-98-8449
Total Synthesis of (S)-(+)-Melodorinol and (S)-(+)-Acetylmelodorinol

Manat Pohmakotr,* Patoomratana Tuchinda, Pornchai Premkaisorn, Attasit Limpongpan, and Vichai Reutrakul

*Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand


(S)-(+)-Melodorinol and (S)-(+)-acetylmelodorinol have been synthesized by reacting the lithiated butenolide with 2,3-O-alkylidene-D-glyceraldehyde followed by successive elimination, hydrolysis, benzoylation and acetylation reactions.

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Paper | Regular issue | Vol 51, No. 4, 1999, pp. 803 - 809
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DOI: 10.3987/COM-98-8452
Synthesis of 2-Imino-3-[1-(β-D-ribofuranosyl)oxo]-1H,5H-1,5-benzodiazepine through Condensation of o-Phenylenediamine with Formylisoxazole Glycoside

Natsu Nishimura, Yuko Koyano, Michiharu Sugiura, and Isamu Maeba*

*Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tenpaku, Nagoya 468-8503, Japan


The synthesis of 3-[1-(β-D-ribofuranosyl)oxo]-1H-1,5-benzodiazepine (3) and 2-imino-3-[1-(β-D-ribofuranosyl)oxo]-1H-1,5-benzodiazepine (8) is described. The cyclocondensation of enaminone glycoside (1) with o-phenylenediamine afforded benzodiazepine (2) in 64% yield. The reaction of formylisoxazole (4) with o-phenylenediamine led to three products, iminobenzodiazepine (5), benzimidazole (6), and enaminone nitrile (7) in 33%, 27%, and 9% yields, respectively. Removal of the sugar protecting groups in 2 and 5 with aqueous sodium carbonate in methanol gave the deprotected C-nucleosides (3 and 8).

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Paper | Regular issue | Vol 51, No. 4, 1999, pp. 811 - 819
Published online:
DOI: 10.3987/COM-98-8459
New Synthesis of 5-Cyano-1,2,4-thiadiazoles

Tsuneo Iwakawa* and Akira Murabayashi

*Aburahi Laboratories, Shionogi & Co. Ltd., Gotanda,Koga-gun, Shiga 520-3423, Japan


Treatment of 4-chloro-5-(3-isoxazolylimino)-5H-1,2,3-dithiazoles with piperidine in dichloromethane gave 5-cyano-1,2,4-thiadiazoles (51.8 %-92.1 % yield).

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Note | Regular issue | Vol 51, No. 4, 1999, pp. 821 - 828
Published online:
DOI: 10.3987/COM-98-8371
Synthesis and Structural Elucidation of Xanthonolignoids: trans-(±)-Kielcorin B and trans-(±)-Isokielcorin B

Eduarda G. R. Fernandes, Madalena M. M. Pinto,* Artur M. S. Silva,* José A. S. Cavaleiro, and Otto R. Gottlieb

*C. E. Q. O. F. F. - UP, Faculdade de FarmÁcia - N° CONT. 600027619, Universidade do Porto, Rua Anibal Cunha, 164, 4050 Porto, Portugal


This paper reports the synthesis and characterization of two isomeric xanthonolignoids - trans-(±)-kielcorin B and trans-(±)-isokielcorin B. The synthetic approach is based on the oxidative coupling of 2,3-dihydroxy-4-methoxyxanthone with coniferyl alcohol in the presence of silver carbonate. The structural elucidation of these compounds was achieved by extensive NMR studies: 1H and 13C NMR spectra, homonuclear correlation spectroscopy (COSY, COSYLR), heteronuclear correlation spectroscopy (HETCOR), nuclear Overhauser effect (NOE) and one-dimensional selective INEPT. The NMR spectroscopic techniques used in this study led to an unambiguous characterisation of trans-(±)-kielcorin B and trans-(±)-isokielcorin B, which includes the assignment of all proton and carbon resonances and the establishment of the substituents orientation and protons configurational relationship on their 1,4-dioxane ring.

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Note | Regular issue | Vol 51, No. 4, 1999, pp. 829 - 832
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DOI: 10.3987/COM-98-8432
Synthesis of 5,7-Dimethylpyrazolo[3',4':4,5]thiazolo[2,3-c]-1,2,4-triazole, an Analogue of Tricyclazole

Chiara B. Vicentini,* Maurizio Manfrini, Donatella Mares, and Augusto C. Veronese

*Dipartimento di Scienze Farmaceutiche, Universita di Ferrara, via Fossato di Mortara 17, I-44100, Ferrara, Italy


An efficient synthesis of 5,7-dimethylpyrazolo[3’,4’:4,5]thiazolo[2,3-c]-1,2,4-triazole (2), an analogue of tricyclazole, was achieved by treatment of 4-(4’-amino-1’,3’-dimethylpyrazol-5’-yl)-1,2,4-triazole-3-thione (7) with sodium nitrite in acidic medium followed by irradiation with UV light.

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Note | Regular issue | Vol 51, No. 4, 1999, pp. 833 - 839
Published online:
DOI: 10.3987/COM-98-8437
An Anomalous Preparing of a Tetrahydro-2H-oxocine Fused Pyrrole Derivative and Its Acid-catalyzed Rearrangement

Shan-Yen Chou,* Lien-Shange Chang, and Shyh-Fong Chen

*Deparatment of Medicinal Chemistry, Development Center for Biotechnology, Hsi-Chih Research Park 102, Lane 169, Kang Ning St, Hsi Chih 221, Taipei Hsien, Taiwan, R.O.C.


Condensation of 5-methylthio-2-benzoylpyrrole (1) with spiro[2.5]-5,7-dioxa-6,6-dimethyloctane-4,8-dione (3) using excess amount of NaH in DMF gave an anomalous tetrahydro-2H-oxocine fused pyrrole (10), which then undergoes an acid-catalyzed rearrangement in refluxing toluene/methanol (10:1, v/v) to afford the unexpected anti-aromatic compounds (15 and 16).

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Note | Regular issue | Vol 51, No. 4, 1999, pp. 841 - 850
Published online:
DOI: 10.3987/COM-98-8446
Three New Rearranged Taxane Diterpenoids from the Bark of Taxus chinensis var. mairei and the Needles of Taxus cuspidata

Shi Qing-wen, Takayuki Oritani,* Takeyoshi Sugiyama, Hiromasa Kiyota, and Tohru Horiguchi

*Division of Liffe Science, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiya, Aoba-ku, Sendai 981-8555, Japan


Three new rearranged taxane diterpenoids with 5/7/6ómembered ring system were isolated from the bark of Taxus chinensis var. mairei (1 and 2) and the needles of T. cuspidata (3). The structures of them were established as 2α,7β-diacetoxy-5α,10β,13α,15-tetrahydroxy-4β(20)-epoxy-9α-benzoy1oxy-11 (15→1)abeotax-11-ene (1), 2α,4α-diacetoxy-7β-benzoyloxy-5β,20-epoxy-9α,10β,13α15-tetrahydroxy-11(15→1)abeotax 11-ene (2), and 4α, 7β-diacetoxy-2α-benzoyloxy-5β,20-epoxy-9α,10β,13α,15-tetrahydroxy-11(15→1)abeotax-11-ene (3) on the basis of spectral data including 2D NMR spectroscopies.

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Note | Regular issue | Vol 51, No. 4, 1999, pp. 851 - 855
Published online:
DOI: 10.3987/COM-98-8457
Structures of a New Coumarin and a New Acridone Dimer from a Citrus Plant

Yuko Takemura, Motoharu Ju-ichi,* Mitsuo Omura, Chihiro Ito, and Hiroshi Furukawa

*Faculty of Pharmaceutical Science, Mukogawa-Women's University, 11-68 Koushien Kyuban-Cho, Nishinomiya, Hyogo 663-8179, Japan


A new coumarin, marshrin (1) and a new dimeric acridone alkaloid, citbismine-F (2) were isolated from the roots of Marsh grapefruit (Citrus paradisi Macf.). Structures of these new compounds were elucidated by spectral analyses especially by HMQC, HMBC and NOE experiments.

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Note | Regular issue | Vol 51, No. 4, 1999, pp. 857 - 861
Published online:
DOI: 10.3987/COM-98-8460
Selective Oxidation of 6-Acetyl-1,3,7-trimethyllumazine by Nitric Acid

Yeonhee Kim, Jaeseung Kim, Shinho Jang, and Yonghan Kang*

*Department of Chemistry, College of Science, Hanyang University, 1271 Sa-1-dong, Ansan-si, Kyunggi-do 425-791, Korea


6-Acetyl and 7-methyl groups of 6-acetyl-1,3,7-trimethyllumazine were oxidized to carboxylic acid by nitric acid. The oxidation of 6-acetyl-1,3,7-trimethyllumazine afforded 1,3,7-trimethyllumazine-6-carboxylic acid or 1,3-dimethyllumazine-6,7-dicarboxylic acid depending on the concentration of nitric acid.

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Review | Regular issue | Vol 51, No. 4, 1999, pp. 863 - 925
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DOI: 10.3987/REV-98-507
Structure and Reactivity of Cycloimmonium Ylides

Yasser Karzazi and Gheorghe Surpateanu*

*Laboratoire de Synthèse Organique et Environnement, Maison de la Recherche Environnement Industriel de Dunkerque, Université du Littoral, 145, Route du Pertuis d'Amont, 59140 Dunkerque, France


In this review have been presented the early results on the structure of cycloinimonium ylides by X-Ray diffraction patterns as well as UV-Vis, Raman and NMR spectra. The quantum mechanics, ab initio and semi-empirical, calculations permited to evaluate all stabilising factors in these specific structures and to demonstrate their reactivity as nucleophilic and 1,3-dipoles reagents in organic synthesis. An important part is affected to the more spectacular synthesis in the class of cycloimmoniurn ylides involving these molecular systems as intermediates or as compounds with specific properties.

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Review | Regular issue | Vol 51, No. 4, 1999, pp. 927 - 940
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DOI: 10.3987/REV-98-516
Chemical Studies on the Nyctinastic Leaf-Movement Regulated by a Biological Clock

Minoru Ueda and Shosuke Yamamura*

*Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku, Yokohama 223-8522, Japan


Most leguminosae plants close their leaves in the evening, as if to sleep, and open them early in the morning. This circadian rhythm is known to be controlled by the biological clock of such plants. Extensive studies on other nyctinastic plants led to the isolation of a variety of leaf-closing and leaf-opening substances. Based on our experiments on these bioactive substances, we found that the circadian rhythmic leaf-movement of these plants is controlled by a biological clock that regulates the balance of concentration between leaf-opening and -closing substances.

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18 data found. 1 - 18 listed