Regular Issue

Vol. 57, No. 4, 2002

14 data found. 1 - 14 listed
Communication | Regular issue | Vol 57, No. 4, 2002, pp. 615 - 621
Published online:
DOI: 10.3987/COM-02-9440
Synthesis, ESI and FAB Mass Spectrometry, and X-Ray Analysis of Di- and Tricationic Pyridinium Substituted Pyrimidines

Andreas Schmidt,* Pirjo Vainiotalo, Markus Karl Kindermann, and Martin Nieger

*Institut für Organische Chemie, Technische Universität Clausthal, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, Germany


Reaction of trichloropyrimidine (5) with 4-(dimethylamino)pyridine or 4-(pyrrolidin-1-yl)pyridine in ethyl acetate in the presence of sodium tetraphenylborate yielded the tricationic pyrimidines (7) and (8). Applying the same reaction conditions to tetrachloropyrimidine (6) resulted in the formation of highly reactive 5-chloro substituted trications (9) and (10), which could be intercepted by anhydrous alcohols to give the dicationic species (11) and (12). Characterizations by means of ESIMS and FABMS, a semiempirical calculation and an X-Ray analysis were performed.

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Communication | Regular issue | Vol 57, No. 4, 2002, pp. 623 - 629
Published online:
DOI: 10.3987/COM-02-9448
Electrolytic Partial Fluorination of Organic Compounds. 59. Highly Regioselective Anodic Monofluorination of 2H-1,4-Pyrido[3,2-b]-1,4-oxazin-3(4H)-one Derivatives

Norio Iwayasu, Mohamed R. Shaaban, and Toshio Fuchigami*

*Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Nagatsuda, Yokohama 226-8502, Japan


Regioselective anodic fluorination of 2H-1,4-pyrido[3,2-b]-1,4-oxazin-3(4H)-one derivatives was successfully carried out in dimethoxyethane containing Et4NF-4HF using an undivided cell to provide the corresponding α-monofluorinated products in moderate yields.

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Communication | Regular issue | Vol 57, No. 4, 2002, pp. 631 - 636
Published online:
DOI: 10.3987/COM-02-9450
The First Reliable, General Synthesis of the 5-Oxo Derivatives of 5,6-Dihydro-1,2,4-triazolo[4,3-c]pyrimidine and the Rates of Isomerization of the [4,3-c] Compounds into Their [1,5-c] Isomers

Tomohisa Nagamatsu* and Takayuki Fujita

*Faculty of Pharmaceutical Science, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan


This paper describes a reliable synthesis of the 5-oxo derivatives (8) of 5,6-dihydro-1,2,4-triazolo[4,3-c]pyrimidine, by the reaction of 2-oxo-1,2-dihydropyrimidin-4-ylhydrazines (7) with the appropriate triethyl orthoesters in trifluoroacetic acid below 30 °C or by the oxidative cyclization of their aldehyde hydrazones (10) with 70% nitric acid in trifluoroacetic acid below 40 °C, and the rates of isomerization of the [4,3-c] compounds (8) into the [1,5-c] isomers (9).

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Paper | Regular issue | Vol 57, No. 4, 2002, pp. 637 - 648
Published online:
DOI: 10.3987/COM-01-9429
Chemoselective Debezylation of the N-1-Phenylethyl Goup in 2-Oxazolidinones by the Anisole-Methanesulfonic Acid System

Shigeo Sugiyama, Kenji Morishita, Mariko Chiba, and Keitaro Ishii*

*Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan


The chemoselective removal of N-1-phenylethyl group in 2-oxazolidinones by the anisole–methanesulfonic acid system was investigated. Optically active 4,5-cis- and 4,5-trans-diphenyl-2-oxazolidinones (1a–d) were easily synthesized from dl-stilbene oxides (trans- and cis-7a) using this debenzylation.

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Paper | Regular issue | Vol 57, No. 4, 2002, pp. 649 - 656
Published online:
DOI: 10.3987/COM-02-9443
A Simple and Practical Preparation of 2,4-Disubstituted 1-Benzotelluropyrylium Salts

Haruki Sashida* and Masahiro Yoshida

*School of Pharmacy, Hokuriku University, 3-Ho, Kanagawa machi, Kanazawa 920-1181, Japan


The treatment of the 2-tert-butyl- (8A) and 2-phenyltellurochromen-4-ones (8B) with Grignard reagents (MeMgBr, EtMgBr, PhMgBr and PhCH2MgCl) gave the corresponding 4-substituted 4-hydroxy-4H-tellurochromenes (9) in good yields, respectively. The obtained compounds (9) were readily transformed into the 2,4-disubstituted 1-benzotelluropyrylium salts (7) by treatment with Ph3C+ BF4- in acetic acid in high yields. The 4-benzyl-1-benzotelluropyrylium salts (7Ad) and (7Bd) were also prepared from the 4-benzyl-tellurochromenes (5), which were obtained by the reaction of the 1-benzotelluropyrylium salts (4) with PhCH2MgCl.

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Paper | Regular issue | Vol 57, No. 4, 2002, pp. 657 - 664
Published online:
DOI: 10.3987/COM-02-9446
Quadruple Photocyclization Reaction Leading to the Cyclophanes Containing Two Benzo[1,2-b:5,4-b’]difuran Rings

Kwanghee Koh Park* and Hongsan Lim

*Department of Chemistry, Chungnam National University, Taejon 305-764, Korea


Irradiation of the macrocycles (4a-b) having two 1,5-dibenzoyl-2,4-dialkoxybenzene moieties with 350 nm mercury lamp followed by dehydration afforded two benzo[1,2-b:5,4-b’]difuran ring-containing cyclophanes (1a-b) via quadruple photocyclization reaction forming four dihydrofuranol ring systems in one pot.

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Paper | Regular issue | Vol 57, No. 4, 2002, pp. 665 - 676
Published online:
DOI: 10.3987/COM-02-9451
Photocycloaddition of 6-Cyano-1,3-dimethyluracil to Alkenes; Synthesis of Tetrahydrocyclobutapyrimidine-6a-carbonitriles

Kazue Ohkura, Hideaki Nakamura, Tatsuyuki Sugaoi, Akiyo Sakushima, Hajime Takahashi, and Koh-ichi Seki*

*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan


UV-Irradiation of 6-cyano-1,3-dimethyluracil (6-CNDMU) and alkenes having electron-donating and electron-withdrawing groups afforded the corresponding cyclobutapyrimidine derivatives with head-to-tail regiochemistry in appreciable yields. Similarly 6-CNDMU coupled with 6-CNDMU or 1,3-dimethyluracil to give trans-syn type cyclobutene pyrimidine dimers, while the reaction with 1,3-dimethylthymine proceeded the coupling reaction non-regio- and stereoselectively.

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Paper | Regular issue | Vol 57, No. 4, 2002, pp. 677 - 695
Published online:
DOI: 10.3987/COM-02-9453
About the Factors Which Govern the Ring-opening of α-Lactams with Benzylamine I. The Relative Stability of the α-Lactam and the Substituent on Nitrogen

István Lengyel,* Victor Cesare, Sihao Chen, and Tony Taldone

*Department of Chemistry, St. John's University, 8000 Utopia Parkway, Jamaica, New York 11439, U.S.A.


Eight α-lactams (aziridinones) of varying stability, one of them previously unreported, were synthesized and reacted with benzylamine. Three of the α-lactams, 1-(1-adamantyl)-3,3-dimethylaziridinone (2j), 3,3-dimethyl-1-triphenylmethylaziridinone (2m), and 3-phenyl-1-triphenylmethyl-aziridinone (2o) gave α-benzylaminoamides (3j, 3m, 3o) as products, indicating C3-N bond cleavage. Four α-lactams, 1,3-di-tert-butylaziridinone (2g), 1-tert-butyl-3-triphenylmethylaziridinone (2i), 1-(1-adamantyl)-3-tert- butylaziridinone (2k), and 1-(1-adamantyl)-3-triphenylmethylaziridinone (2l) yielded N-benzylamides (4g, 4i, 4k, 4l), resulting from C2-N bond cleavage. 3-(1-Adamantyl)-1-triphenylmethylaziridinone (2n) gave a mixture of both types of adduct (3n, 4n). Based on these experimental results, two important factors which govern the ring-opening of α-lactams are the relative stability of the α-lactam and the substituent on nitrogen.

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Note | Regular issue | Vol 57, No. 4, 2002, pp. 697 - 704
Published online:
DOI: 10.3987/COM-01-9369
Chemical Oxidation of Synthetic Iron(III)-Complex of 15-Phenyl Protoporphyrin IX

Fernando Niemevz, Diego E. Alvarez, and Graciela Y. Buldain*

*Cátedra de Química Orgánica II, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 3er. piso. (1113) Buenos Aires, Argentina


Oxidative cleavage of 15-phenyl protohemin IX in pyridine solution in the presence of ascorbic acid (coupled oxidation), followed by esterification of the products with boron trifluoride-methanol rendered only three isomeric biliverdins. These were identified by 1H NMR and MS spectrometry as 10-phenyl biliverdin IXα (1), 5-phenyl biliverdin IXβ (2) and 15-phenyl biliverdin IXδ (3) dimethyl esters. The fact that biliverdin IXγ dimethyl ester derivative is not obtained indicates that oxidation fails to occur in the γ-meso-carbon bearing the phenyl group.

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Note | Regular issue | Vol 57, No. 4, 2002, pp. 705 - 714
Published online:
DOI: 10.3987/COM-01-9403
The Determination of Enantiomeric Excess of the Products of Baker’s Yeast-mediated Reduction of δ-Alkoxycarbonyl-β-keto Esters, via the Derivation to Alexakis’ Alkoxydiazaphosphoridine

Jacek Nowacki, Jerzy Szychowski, Krystyna Wojtasiewicz, Iwona Matuszewska, Magdalena Jaremko, and Zbigniew Czarnocki*

*Faculty of Chemistry, Warsaw University, Pasteura St.1, 02-093 Warsaw, Poland


Reduction of 5–alkoxycarbonyl–3–oxopentanoates (1a1j) with baker’s yeast turned to be enantioselective, and the of the products (2a2j) were determined by the NMR measurement of the corresponding Alexakis‘ alkoxydiazaphosphoridines. Stereochemistry was established with X–Ray crystallography.

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Note | Regular issue | Vol 57, No. 4, 2002, pp. 715 - 721
Published online:
DOI: 10.3987/COM-01-9430
Two New Withanolides from the Aerial Parts of Datura innoxia

Bina S. Siddiqui,* Imran Ali Hashmi, and Sabira Begum

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


Two new withanolides named as withametelinol-A (1) and withametelinol-B (2) have been isolated from the aerial parts of Datura innoxia. Their structures have been elucidated as (20R, 22R)-21,24-epoxy-5β-hydroxy-1-oxowitha-2,9(11),25(27)-trienolide and (20R, 22R)-21,24-epoxy-12α-hydroxy-1-oxowitha-3,5,25(27)-trienolide respectively through spectroscopic studies.

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Note | Regular issue | Vol 57, No. 4, 2002, pp. 723 - 731
Published online:
DOI: 10.3987/COM-01-9431
Simple Synthesis of Ring-fused Pyridazin-3-ones

Koichi Suzuki, Akihiro Senoh, and Kazunori Ueno*

*OL Project, Display Development Headquarters, Canon Inc., 30-2 Shimomaruko 3-chome, Ohta-ku, Tokyo 146-8501, Japan


Bicyclic and tricyclic pyridazin-3-ones, 6,7-dihydro-5H-cyclopenta-[e]-2H-pyridazin-3-one (5), 5,6,7,8-tetrahydrobenzo[e]-2H-pyridazin-3-one (6),9,10-dihydronaphtho[1,2-e]-2H-pyridazin-3-one (15) and 9,10-dihydronaphtho[1,2-e]-2-methylpyridazin-3-one (21) were prepared in a one-pot procedure by reacting hydrazine hydrate with a corresponding ketocarboxylic acid.

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Note | Regular issue | Vol 57, No. 4, 2002, pp. 733 - 739
Published online:
DOI: 10.3987/COM-02-9432
Flavone Glycosides and Bergenin Derivatives from Tridax procumbens

Erum Akbar, Abdul Malik,* Nighat Afza, and S. M. Abdul Hai

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


Tridaxidone, a new flavone glycoside (3) and two bergenin derivatives (4) and (5) have been isolated along with two known flavone glycosides (1) and (2) from the ethyl acetate soluble portion of the ethanolic extract of Tridax procumbens. The structures of 3, 4 and 5 were established through spectroscopic studies.

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Note | Regular issue | Vol 57, No. 4, 2002, pp. 741 - 747
Published online:
DOI: 10.3987/COM-02-9456
The Formation of Spiro-bridged Dimers of Cyclooctane-1,2-dicarbonyl Compounds via Domino Aldol-Cycloalkylation

Michael Oelgemöller, Keijiro Fukui, Dusan Hesek, Fumiko Aoki, Makiko Niki, and Yoshihisa Inoue*

*Inoue Phorochirogenesis Project, ERATO, JST, 4-6-3 Kamishinden, Osaka 565-0085, Japan


Starting from the corresponding 8-membered cyclic 1,2-diones, spiro-bridged cyclic dimers were prepared in moderate to good yields via barium oxide/ hydroxide mediated coupling, followed by in situ methylation with dimethyl sulfate.

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14 data found. 1 - 14 listed