Regular Issue

Vol. 27, No. 11, 1988

22 data found. 1 - 22 listed
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2517 - 2522
Published online:
DOI: 10.3987/COM-88-4624
Antimicrobial Agents from Higher Plants. The Isolation and Structural Characterization of Two Additional Pterocarpan Antimicrobial Agents from Nigerian Erythrina mildbraedii

Lester A. Mitscher,* Simon K. Okwute, Sitaraghav R. Gollapudi, and Ali Keshavarz-Shokri

*Department of Medicinal Chemistry, Kansas University, Lawrence, Kansas 66045, U.S.A.

Abstract

Examination of bioactive mother-liquors from previous large scale experiments on the antimicrobial agents from the Nigerian medicinal plant, Erythrira mildbraedii, led to the isolation and structural characterization of two new pterocarpans, erybraedin D and E. Erybraedin D was initially isolated as its apparently artifactual hemiethyl phthalate ester. Both new pterocarpans possess marginal antimicrobial potency in vitro.

PDF (164KB)
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2523 - 2526
Published online:
DOI: 10.3987/COM-88-4672
‘Umpolung’ of Reactivity at C-5 Position of Uracil: An Unprecedented Nucleophilic Reaction of Thiolane Ion at C-5 of 6-Cyano-1,3-dimethyluracil

Subodh Kumar* and Swapandeep Singh Chimni

*Department of Applied Chemical Sciences & Technology, Guru Nanak Dev University, Amritsar 143 005, India

Abstract

The soft thiolate ions react with 6-cyano-1,3-dimethyluracil at C-5 to give 5-alkylthio-1,3-dimethyluracil derivatives as major products.

PDF (92KB)
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2527 - 2529
Published online:
DOI: 10.3987/COM-88-4691
Regiospecific Preparation of 2-Oxazolines Promoted by Silicon Tetrafluoride

Makoto Shimizu* and Hirosuke Yoshioka*

*The Institute of Physical and Chemical Research, Wako-shi, Saitama 351-0198, Japan

Abstract

Silicon tetrafluoride promotes reaction of oxiranes with nitriles to give 2-oxazolines in good yield.

PDF (72KB)
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2531 - 2534
Published online:
DOI: 10.3987/COM-88-4693
Intermolecular Heteroaromatic Nucleophilic Substitution Reaction via the Sulphur Ylide Rearrangement: C-Attack vs. O-Attack

Tetsuji Kametani,* Kuniaki Kawamura, Takeshi Akagi, Chikako Fujita, and Toshio Honda

*Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan

Abstract

Intermolecular aromatic nucleophilic substitution reaction of the heterocyclic sulphide derivatives with α-diazo esters in the presence of rhodium (II) acetate was investigated to give the oxygen-introduced products via the sulphur ylide rearrangement.

PDF (83KB)
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2535 - 2537
Published online:
DOI: 10.3987/COM-88-4705
Synthesis of (2R,3S)-2-Hydroxymethyl-3-hydroxypyrrolidine and the Geissman-Waiss Lactone from (S)-Pyroglutamic Acid

Nobuo Ikoto* and Akira Hanaki

*National Institute of Radiological Sciences, 9-1, Anagawa-4-Chome, Inage-ku, Chiba 263-0024, Japan

Abstract

The synthesis of (2R,3S)- and (2R,3R)-2-hydroxymethyl-3-hydroxypyrrolidine derivatives (5 and 7) and the Geisman-Waiss lactone (12) has been achieved from (S) -pyroglutamic acid.

PDF (77KB)
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2539 - 2544
Published online:
DOI: 10.3987/COM-88-4706
The Light Induced Conversation of Thieno[2,3-c]isothiazoles into Thiophenes

Antonino Corsaro, Francesco Guerrera, Maria C. Sarvà, and Maria Siracusa

*Istituto di Chimica Farmaceutica e Tosshicologica, Università di Catania, Viale A. Doria 6, I-95125 Catania, Italy

Abstract

The sun light induced conversion of thieno[2,3-c]isothiazoles 1a-d into thiophenes 2a-d, with loss of elemental sulfur is reported. A presumable mechanism for the thiophene nucleus formation is discussed to involve the opening of the two heterocyclic rings with formation of an open-chain valence bond isomer through the initial homolytic cleavage of the isothiazole N-S linkage.

PDF (137KB)
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2545 - 2548
Published online:
DOI: 10.3987/COM-88-4708
Synthesis and Anti-HIV Activity of 3’-Cyano-2’,3’-dideoxythymidine and 3’-Cyano-2’,3’-didehydro-2’,3’-dideoxythymidine

Akira Matsuda,* Mutsumi Satoh, Hideki Nakashima, Naoki Yamamoto, and Tohru Ueda

*Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812, Japan

Abstract

3’-Cyano-2’,3’-dideoxy- and 3’-cyano-2’,3’-didehydro-2’,3’-dideoxythymidines (4,5) have been synthesized from 5-methyluridine (7). Anti-HIV activity of these compounds is also described.

PDF (109KB)
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2549 - 2556
Published online:
DOI: 10.3987/COM-88-4709
Asymmetric Electrophilic α-Amidoalkylation 5: Improved Stereoselectivities through New Chiral Auxiliaries

Klaus Th. Wanner,* Annerose Kärtner, and Elmar Wadenstorfer

*Institut für Pharmazie und Lebensmittelchemie, Universität München, Sophienstraße 10, D-80333 München, Germany

Abstract

Enamides of type 2 were employed in asymmetric α-amidoalkylation reactions with silyl enol ether 4 as nucleophile. Depending on the chiral auxiliary used, (R)-5/(S)-5 stereoselectivities up to 95/5 could be reached. Based on the obtained results a model for the transient acyliminium ion is proposed.

FREE:PDF (156KB)
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2557 - 2562
Published online:
DOI: 10.3987/COM-88-4733
Site Selectivity in the 1,3-Dipolar Cycloaddition Reaction of Unsymmetric Pyridinium Bis(methoxycarbonyl)methylides with Methyl Propiolate

Kiyoshi Matsumoto,* Yukio Ikemi, Hideyuki Konishi, Xiao-lan Shi, and Takane Uchida

*Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-Nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan

Abstract

The 1,3-dipolar cycloaddition of.unsymmetric pyridinium bis(methoxycarbonyl)methylides with methyl propiolate proceeds in moderate to good yields with high to moderate site selectivity with respect to the ylide. Polar 3-substituted pyridinium bis(methoxycarbonyl)methlides generally gave predominantly the corresponding 8-substituted indolizines regardless of the substituents. The results can be explained by dipole-dipole interactions.

PDF (117KB)
Communication | Regular issue | Vol 27, No. 11, 1988, pp. 2563 - 2566
Published online:
DOI: 10.3987/COM-88-4744
Chemistry on Benzopentathiepin. Reactios of Benzopentathiepin with Aromatic Compounds in the Presence of Lewis Acid

Ryu Sato,* Akira Onodera, Takehiko Goto, and Minoru Saito

*Department of Applied Chemistry, Faculty of Engineering, Iwate University, 4-3-5 Ueda, Morioka, Iwate 020-8551, Japan

Abstract

Benzopentathiepin (BPT) reacted with many aromatic compounds such as benzene, 1,4-dimethylbenzene, and naphthalene in the presence of Lewis acid to give various thianthrenes in moderate yields. BPT was found to serve as a 1,4-dication synthon.

PDF (93KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2567 - 2576
Published online:
DOI: 10.3987/COM-88-4495
On the Reactivity of 5(4H)-Oxazolones with Amines

Javier Blasco, Carlos Cativiela, María D. Díaz de Villegas, José I. García, Carlos Jaime, and José A. Mayoral

*Departamento de Quimica Organica, Facultad de Ciencias -I Instituto de Ciencia de los Materiales de Aragón, Universidad de Zaragoza, E-50009 Zaragoza, Aragon, Spain

Abstract

Reactions of (Z/E)-2-phenyl-4-(α-arylethylidene)-5(4H)-oxazolones and Z-2-phenyl-4-arylmethylene-5(4H)-oxazolones with nucleophiles occur with retention of the exocyclic double band geometry, whereas reactions of E-2-phenyl-4-arylmethylene-5(4H)-oxazolones with some nucleophiles occur with total or partial isomerization. Structural calculations, MNPI and AM1, on model compounds reveal that the methyl group does not essentially affect the phenyl ring-double bond planarity. Application of the Klopman-Salem equation to the reaction of E-2-phenyl-4-benzylidene-5(4H)-oxazolone with different amines, calculated by MNDO, points to a reversible nucleophillc attack at the exocyclic carbon of this 5(4H)-oxazolone as a possible explanation of this behaviour. As Z-2-phenyl-4-benzylidene-5(4H)-oxazolone is more stable than the E-isomer, the opening reactions of the Z-compound occur without isomerization.

PDF (199KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2577 - 2580
Published online:
DOI: 10.3987/COM-88-4550
Peculiar C-C Bond Cleavages of Pyrazolyl Propenone Epoxides Induced by Grignard Reagents

Ali El-Shekeil,* Abdulla Babaqi, Mohammed Hassan, and Sayed Shiba

*Chemistry Department, Faculty of Science, Sana‘s University, Sana‘s, Yemen

Abstract

1-Aryl-3-(5-chloro-1,3-diphenyl-1H-4-pyrazalyl)prop-2-en-1-ones(2) yielded pyrazolylpropenone epoxides (3) on which peculiar C-C bond cleavages were induced by Grignard reagents giving the unexpected saturated secondary alcohols (4) bearing pyrazolyl nucleus.

PDF (102KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2581 - 2588
Published online:
DOI: 10.3987/COM-88-4618
3,7-Bis(carbothoxy)perhydro-1,5,2,4,6,8-dithiatetrazocime 1,1,5,5-tetroxide. Synthesis, Structure and Chemistry

Chai-Ho Lee and Harold Kohn*

*Department of Chemistry, University of Houston, Houston, TX 77004, U.S.A.

Abstract

The synthesis and single-crystal X-ray crystallographic analysis of 3,7-bis(carboethoxy)perhydro-1,5,2,4,6,8,-dithiatetrazocine 1,1,5,5-tetroxide (1) and the corresponding permethylated derivative 2 is detailed. The use of 1 in electrophilic aromatic substitution transformations with benzene, toluene, and anisole is also described.

PDF (230KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2589 - 2594
Published online:
DOI: 10.3987/COM-88-4619
Xanthonolignoids from Hypericum subalatum

Ming-Tyan Chen*

*Department of Applied Chemistry, Chia Nan Junior College of Pharmacy, Tainan, 71710, Taiwan, R.O.C.

Abstract

The isolation and characterization of three xanthonolignoids, kielcorin, cadensin D, and a new compound named as subalatin, from the whole plant of Hypericum subalatum Hayata are described.

PDF (130KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2595 - 2607
Published online:
DOI: 10.3987/COM-88-4638
Selective Syntheses of Analogues of the Natural Precocenes. Synthesis and Regioselective O-Alkylation of 6-Chloro- and 6-tert-Butyl-7,8-dihydroxy-2,2-dimethyl-4-chromanones

Péter Sebök, Tibor Timár,* Joseph Csaba Jászberényi, and Gyula Batta

*Department of Research, Alkaloida Chemical Co. Ltd., H-4440 Tiszavasvári, POB 1, Hungary

Abstract

The synthesis of novel benzopyran compounds 16 a-f, analogues of the natural precocenes (1 and 2) is described. These derivatives are obtained via novel synthesis and regioselective 0-alkylation of 6-chloro-and 6-tert-butyl-7,8-dihydroxy-2,2-dimethyl-4-chromanones (7 and 12).

PDF (258KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2609 - 2618
Published online:
DOI: 10.3987/COM-88-4668
Chemistry of N-Chloronortropine Derivatives: Synthesis of a Bridgeed Aziridine Compound and New Tropane Derivatives

Syuichi Furuya* and Toshihiko Okamoto

*Central Research Division, Takeda Chemical Industries, Ltd., 17-85 Jusohonmachi 2-chome, Yodogawa-ku, Osaka 532-8686, Japan

Abstract

An unsymmetrical bridged aziridine compound was obtained from N-chloronortropinone. This compound was found to react with acyl halides, acid anhydrides, and other reagents, including a Michael acceptor, dimethyl acetylenedicarboxylate (DMAD), giving new tropane bases with a ketone functional group at the bridged ethylene moiety. In the case of Michael-type addition, the retention of the aziridine ring system was observed in some solvents.

PDF (247KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2619 - 2625
Published online:
DOI: 10.3987/COM-88-4684
Reactions of Triethyl[1-(N-tert-Butylimisoyl)-2-pyrrolinyl]borate with Electrophiles

Minoru Isikura and Masanao Terashima*

*Faculty of Pharmaceutical Scicences, Higashinihonngakuen University, 1757 Kanazawa, Toubetu-cho, Ishikari-gun, Hokkaodo 061-0212, Japan

Abstract

The reaction of triethyl[1-(N-tert-butylimidoyl)-2-pyrrolinyl)borate (2) with alkyl halides, allylic bromides, alkenyliodonium salt, and N-carbophenoxypyridinium chloride in the absence or the presence of copper(I) ion were investigated.

PDF (152KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2627 - 2633
Published online:
DOI: 10.3987/COM-88-4688
Diarryl-α-heteroarylmalonates from Cerium(IV)-promoted Reactions of Dialkyl Malonates with Heterocyclic Compounds

Leonard M. Weinstock,* Edward Corley, Newton L. Abramson, Anthony O. King, and Sandor Karady*

*Division of Merec and Co., Inc., Merck Sharp and Dohme Research Laboratories, Rahway, New Jersey 07065, U.S.A.

Abstract

Thiophenes, furans and their benzo analogs undergo facile malonylation in the 2-position on reaction with dialkyl malonate radicals generated with cerium(IV) reagent.

PDF (162KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2635 - 2641
Published online:
DOI: 10.3987/COM-88-4699
Synthesis of 2,4-Dioxoimidazolidines from 2-Arylimino-1,3-thiazines and Their Antifungal Activity

Mitsuhiro Ichinari, Kuniyoshi Nakayama, and Yoshio Hayase

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

Abstract

2,4-Dioxoimidazolidines were obtained by the reaction of 2-arylimino-1,3-thiazines with chloroacetyl chloride (CAC) under aqueous alkaline conditions. Some derivatives of 2,4-dioxoimidazolidines exhibited antifungal activity against downy mildew.

PDF (144KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2643 - 2650
Published online:
DOI: 10.3987/COM-88-4712
A Convenient Synthesis of Azaanthraquinones via Polar Addition to Hetaryne Intermediates. Use of Carbaninons Derived from 3-Cyano-1(3H)-isobenzofuranones

Subhash P. Khanapure and Edward R. Biehl

*Department of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, TX 75275-0314, U.S.A.

Abstract

A convenient synthesisof 2-azaanthraquinones using the reaction of carbanions derived from 3-cyano-1(3H)-isobenzofuranones which serve as 1,4-dipole equivalents and hetaryne intermediates generated from bromopyridines and lithium diisopropylamide is reportted.

PDF (204KB)
Paper | Regular issue | Vol 27, No. 11, 1988, pp. 2651 - 2658
Published online:
DOI: 10.3987/COM-88-4747
Syntheses of Natural Coumarinolignans: Oxidative Coupling of 7,8-Dihydroxycoumarins and Phenylpropenes in the Presence of Diphenyl Selenoxide

Hitoshi Tanaka, Masaya Ishihara, Kazuhiko Ichino, and Kazuo Ito*

*Faculty of Pharmacy, Meijo University, 150 Yagoto, Tempaku-ku, Nagoya, Aichi 468-8503, Japan

Abstract

Oxidative coupling of 7,8-dihydroxycoumarins (1, 2) and phenylpropenes (3-5) using Ph2Se0 as oxidizing agent resulted in remarkably efficient synthesis of naturally occurring coumarinolignans (cleomiscosin A (6A), aquillochin (cleomiscosin C)(6B), daphneticin (6C), and propacin (6D)).

PDF (247KB)
Review | Regular issue | Vol 27, No. 11, 1988, pp. 2659 - 2776
Published online:
DOI: 10.3987/REV-88-388
C-Substitution of Nitrogen Heterocycles

Helmut Vorbüggen* and Manfred Maas

*Research Laboratories, Schering AG, Berlin / Bergkamen, D-1000 Berlin 65, Germany

Abstract

An attempt has been made to summarize, evaluate and compare the available methods for the introduction of C-substituents into aromatic nitrogen heterocycles. However due to the large number of publications on this topic this review is necessarily limited to the most important pubilcations.

PDF (2.1MB)
22 data found. 1 - 22 listed