Special Issue

Bernhard Witkop's Special Issues, Vol. 49, No. 1, 1998

69 data found. 61 - 69 listedFirst Previous
Note | Special issue | Vol 49, No. 1, 1998, pp. 465 - 468
Published online:
DOI: 10.3987/COM-98-S25
A New Cleavable Carbene-generating Reagent with 3-Phenyl-3-trifluoromethyldiazirine Photophore

Uwe Kempin, Yuichi Kanaoka, and Yasumaru Hatanaka*

*Research Institute for Wakan-Yaku, Toyama Medical and Pharmaceutical University, Sugitani 2630, Toyama 930-0194, Japan

Abstract

Synthesis of a 3-phenyl-3-trifluoromethyldiazirine derivative having a clevable 1,2-diol moiety for photocross-linking technique is described. An ester of cinnamic acid derivative was prepared by the Witting reaction of 2-methoxy-4-[3-trifluoromethyl-3H-diazirin-3-yl]benzaldehyde which can be readily prepared by the Friedel-Crafts reaction of corresponding phenyldiazirine. The osmium oxidation of the olefinic bond gave the desired diol derivative, ethyl 2,3-dihydroxy-3-[2-methoxy-4-(3-trifluoromethyl-3H-diazirin-3-yl)phenyl]propionate, in a high yield. The cleavability of the diol group was confirmed by the conventional periodate oxidation to give the starting aldehyde.

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Note | Special issue | Vol 49, No. 1, 1998, pp. 469 - 474
Published online:
DOI: 10.3987/COM-98-S30
Difference in Guest Binding Capability between Cyclodextrins Having an Acetylamino Moiety at Primary- and Secondary-Hydroxyl Sides: The Effect of Ring Distortion

Iwao Suzuki,* Yoshinobu Sakurai, Koki Obata, Tetsuo Osa, and Jun-ichi Anzai

*Faculty of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan

Abstract

A γ-cyclodextrin (γ-CyD) derivative prossessing an acetylamino moiety at its secondary hydroxyl side can bind only one guest molecule into its distorted cavity. The γ-CyD derivative could discriminate the chirality of some terpene guests in binding strength.

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Note | Special issue | Vol 49, No. 1, 1998, pp. 475 - 479
Published online:
DOI: 10.3987/COM-98-S53
Reduction of Uracil Derivatives with an NADH Model, 1-Benzyl-1,4-dihydronicotinamide

Kosaku Hirota,* Keiko Kubo, Yukio Kitade, and Hironao Sajiki

*Laboratory of Medicinal Chemistry, Gifu Pharmaceutical University, Mitahora-higashi, Gifu 502-8585, Japan

Abstract

Among various C(5)-, N(1)-, and N(3)-substituted uracils, 1-substituted 5-nitrouracil derivatives were reduced by an NADH model, 1-benzyl-1,4-dihydronicotinamide, to give 5,6-dihydro-5-nitrouracil derivatives, the formation of which was accelerated to a large extent by the use of Mg2+ as a catalyst.

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Note | Special issue | Vol 49, No. 1, 1998, pp. 481 - 488
Published online:
DOI: 10.3987/COM-98-S55
Acetylcholinesterase Inhibiting Triterpenoidal Alkaloids from Buxus hyrcana

Atta-ur-Rahman,* Shehnaz Parveen, Asaad Khalid, Afgan Farooq, S. A. Majid Ayatollahi, and M. Iqbal Choudhary*

*International Centre for Chemical Sciences, H. E. J. Research Institute of Chemistry, University of Karachi, Karachi-75270, Pakistan

Abstract

Buxus hyrcana of Iranian origin has yielded two new trierpenoidal alkaloids (-)-hyrcanine (1) and (+)-homomoenjodaramine (2) along with a previously known compound, moenjodaramine (3), which has been obtained for the first time from this species. Compounds (2) and (3) were found to be potent acetylcholinesterase inhibitors.

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Note | Special issue | Vol 49, No. 1, 1998, pp. 489 - 497
Published online:
DOI: 10.3987/COM-98-S60
Synthesis and Biological Evaluation of 14-Alkoxymorphinans. 16. 14-O-Alkyl Derivatives of the μ-Opioid Receptor Antagonist Cyprodime

Helmut Schmidhammer,* Roland Krassnig, Elisabeth Greiner, and John R. Traynor*

*Institute of Pharmaceutical Chemistry, University of Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria

Abstract

The 14-O-benzyl derivatives of cyprodime and 3-hydroxycyprodime (compounds (5) and (6), respectively) were synthesized in several steps from 3-desoxynaltrexone (2a) and naltrexone (2), respectively. In the mouse vas deferens preparation it was found that a 14-O-benzyl group could enhance μ opioid receptor affinity in cyprodime while the μ affinity of 3-hydroxycyprodime was not changed.

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Review | Special issue | Vol 49, No. 1, 1998, pp. 499 - 530
Published online:
DOI: 10.3987/REV-98-SR1
Pictet-Spengler Reactions of Nb-Hydroxytryptamines and Their Application to the Synthesis of Eudistomins

Tohru Hino and Masako Nakagawa*

*Faculty of Pharmaceutical Sciences, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba-shi 263-8522, Japan

Abstract

Methods for preparing Nb-hydroxytryptamines, their Pictet-Spengler reactions with various aldehydes via nitrones, and their asymmetric inductions are reviewed. Syntheses of oxathiazepine-containing eudistomins and related natural products which incorporate these reactions are also reviewed.

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Review | Special issue | Vol 49, No. 1, 1998, pp. 531 - 556
Published online:
DOI: 10.3987/REV-98-SR2
Survey of Oxygenated 2,11-Cyclized Cembranoids of Marine Origin

Patrick Bernardelli and Leo A. Paquette*

*Evans Chemical Laboratories, The Ohio State University, Columbus, OH 43210, U.S.A.

Abstract

The structure, source, and biological activities of the many known members of the four classes of oxygenated 2,11-cyclized cembranoid natural products are compiled in tabular form. The cladiellins, briarellins, asbestinins, and sarcodictyins have been purposefully organized to highlight biological activity interrelationships.

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Review | Special issue | Vol 49, No. 1, 1998, pp. 557 - 586
Published online:
DOI: 10.3987/REV-98-SR3
Synthesis of 1,3,4-Thiadiazines and 1,3,4-Oxadiazines

Ho Sik Kim* and Yoshihisa Kurasawa*

*School of Pharmaceutical Sciences, Kitasato University, Shirokane, Minato-ku, Tokyo 108-8641, Japan

Abstract

This review summarizes several methods for the synthesis of 1,3,4-thiadiazines and 1,3,4-oxadiazines reported in 1960s-1990s.

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Review | Special issue | Vol 49, No. 1, 1998, pp. 587 - 618
Published online:
DOI: 10.3987/REV-98-SR4
Stable Heterocyclic Five-membered Azomethine Imines: Azolium N-Imides, Triazolidinium and Pyrazolidinium Ylides

Ludmila L. Rodina,* Arne Kolberg, and Bärbel Schulze

*St.-Petersburg State University, Department of Organic Chemistry, 199004 St.-Petersburg, Srednij pr. 41, Russia

Abstract

This review described two types of stable heterocyclic five-membered azomethine imines. Firstly, aromatic stabilized azomethine imines (azolium N-imides), containing the C-N-bond in a heteroaromatic five-membered ring. Secondly, non-aromatic stabilized compounds incorporating two N-atoms of the azomethine imine moiety in a five-membered ring and an exocyclic C-atom — triazolidione azomethine imines (or triazolindione ylides), pyrazolidone azomethine imines, and their analogues. Their preparation, structures, and some reactions are considered.

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69 data found. 61 - 69 listedFirst Previous