Regular Issue

Vol. 57, No. 5, 2002

12 data found. 1 - 12 listed
Communication | Regular issue | Vol 57, No. 5, 2002, pp. 781 - 785
Published online:
DOI: 10.3987/COM-02-9459
Enantioselective Synthesis of (-)-N-Boc-7-azabicyclo[2.2.1]heptan-2-one and (+)-N-Boc-4-amino-2-cyclohexen-1-one: Formal Total Synthesis of Both Enantiomers of Epibatidine

Toru Tachihara, Hiroyuki Watanabe, and Takeshi Kitahara*

*The University of Tokyo, Graduate School of Agricultural and Life Sciences, Department of Applied Biological Chemistry, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan


we succeeded in the stereoselective synthesis of (—)-N-Boc-7- azabicyclo[2.2.1]heptan-2-one ((—)-2) and (+)-N-Boc-4-amino-2-cyclo- hexen-1-one ((+)-3), key intermediates to (—) and (+)-epibatidine from a common chiral building block ethyl (1R,2S)-5,5-ethylenedioxy-2- hydroxycyclohexanecarboxylate (4) . This constitutes the formal total synthesis of both enantiomers of epibatidine, a potent analgesic.

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Communication | Regular issue | Vol 57, No. 5, 2002, pp. 787 - 790
Published online:
DOI: 10.3987/COM-02-9464
Formation of Boroxine: Its Stability and Thermodynamic Parameters in Solution

Yuji Tokunaga,* Hiroki Ueno, Youji Shimomura, and Toshihiro Seo

*Fukui University, Faculty of Engineering, Faculty of Engineering, Faculty of Engineering


Condensation of three boronic acids proceeding at room temperature gave their corresponding boroxines; NMR spectral measurements revealed that the reaction was reversible at room temperature, that electron-donating groups supported the formation of boroxine, and that entropically driven forces promoted the formation of boroxine in solution.

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Paper | Regular issue | Vol 57, No. 5, 2002, pp. 791 - 809
Published online:
DOI: 10.3987/COM-02-9433
4-[3-Dimethylamino-1-(2-dimethylaminovinyl]prop-2-enylidene]-2-phenyl-1,3-oxazol-5(4H)-one and 5-[3-Dimethylamino-1-(2-dimethylaminovinyl)prop-2-enylidene]-3-methyl-2-thioxo-1,3-thiazolidin-4-one in the Synthesis of 1,4-Dihydropyridine Derivatives

Ales Hvala, Lucija Jukic Sorsak, Gorazd Sorsak, Urska Bratusek, Jurij Svete,* Nina Lah, Ivan Leban, and Branko Stanovnik*

*Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, P.O. Box 537, SLO-1000 Ljubljana, Slovenia


4-{3-Dimethylamino-1-[2-(dimethylamino)vinyl]prop-2-enylidene]-2-phenyl-1,3-oxazol-5(4H)-one (3) and 5-{3-dimethylamino-1-[2-(dimethyl-amino)vinyl]prop-2-enylidene]-3-methyl-2-thioxo-1,3-thiazolidin-4-one (15) were prepared from 4-(1-methylethylidene)-2-phenyl-1,3-oxazol-5(4H)-one (2) and 5-(1-methylethylidene)-2-thioxo-1,3-thiazolidin-4-one (11), respectively. Treatment of compounds (3) and (15) with primary amines afforded 1,4-dihydropyridine derivatives (5) and (16) in 19-94% yields. Reactions of oxazolones (5) with hydrazine hydrate gave the corresponding imidazolones (6), while upon base- or acid-catalysed methanolysis of 5 methyl (benzoylamino)(1-substituted pyridin-4(1H)-ylidene)acetates (7) were obtained. Catalytic hydrogenation of 7a furnished α-(piperidin-4-yl)glycine derivative (8) and/or α-(pyridin-2-yl)glycine derivative (9).

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Paper | Regular issue | Vol 57, No. 5, 2002, pp. 811 - 823
Published online:
DOI: 10.3987/COM-02-9436
A Generalized Synthesis of 3-Amino-5-aryl-, 3-Amino-5-polyfluorophenyl-, and 3-Amino-5-alkyl-1,2,4-oxadiazoles through Ring-degenerate Rearrangements

Silvestre Buscemi,* Andrea Pace, Vincenzo Frenna, and Nicolò Vivona

*Dipartimento di Chimica Organica "E. Paterno", Universita degli Studi di Palermo , Viale delle Scienze-Parco d’Orleans II, I-90128, Palermo, Italy


A generalized synthesis of 3-amino-5-aryl-, 3-amino-5-polyfluorophenyl- and 3-amino-5-alkyl-1,2,4-oxadiazoles has been developed starting from the 3-amino-5-methyl-1,2,4-oxadiazole as a common synthon. Aroylation or alkanoylation of this aminooxadiazole, followed by thermally-induced ring-degenerate equilibration of resulting 3-acylamino compounds, and final acid hydrolysis of the 3-acetylamino-5-aryl- (or 5-polyfluorophenyl-), or 3-acetylamino-5-alkyl-1,2,4-oxadiazoles counterpart which is formed, gave the expected 3-amino-5-substituted 1,2,4-oxadiazoles. In the case of some 3-aroylamino compounds, yields of final 3-amino-5-aryloxadiazoles are higher than that expected on the basis of the thermally-induced equilibrium composition, since acid hydrolysis plays a significant role in the shift of the equilibrium itself. Satisfactory direct procedures have also been described. As expected, restrictions to the above methodology were found in the synthesis of 5-perfluoroalkyl derivatives.

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Paper | Regular issue | Vol 57, No. 5, 2002, pp. 825 - 855
Published online:
DOI: 10.3987/COM-02-9437
Synthesis of Asymmetric Dibenzophosphole 5-Oxides: The First Dibenzophosphole-based Family of Compounds with Liquid Crystalline Behaviour

Ernesto Durán, Dolores Velasco, and Francisco López-Calahorra*

*Departamento de Química Orgánica, Universitat de Barcelona, Martí Franques, 1-11, E-08028 Barcelona, Spain


A synthesis of a new family of chiral dibenzophosphole 5-oxides is described. Using high-yield known reactions we report a method for the synthesis and optical resolution of chiral dibenzophospholes from an unsubstituted system. These molecules are the first examples of a new asymmetrically substituted dibenzophosphole-based group of systems with liquid crystal properties.

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Paper | Regular issue | Vol 57, No. 5, 2002, pp. 857 - 870
Published online:
DOI: 10.3987/COM-02-9447
Synthesis of Heterocycle Substituted 1-Aryl-4-piperidones

Baihua Hu,* Michael Malamas, and John Ellingboe

*Chemical Sciences, Wyeth Research, Collegeville, PA 19426, U.S.A.


A series of heterocycle substituted 1-aryl-4-pipeidones were preparedvia Knoevenagel condensations between nitrogen-containing 5-membered heterocycles and benzaldehyde (1) followed by reduction or amination. Theoxadiazolidinedione ring was formed by reacting the N-hydroxyurea (10) with methyl chloroformate and sodium hydride.

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Paper | Regular issue | Vol 57, No. 5, 2002, pp. 871 - 879
Published online:
DOI: 10.3987/COM-02-9463
Synthesis of 8-Substituted Xanthine Derivatives by Suzuki Cross-Coupling Reaction

Karl Vollmann and Christa E. Müller*

*Pharmaceutical Institute Poppelsdorf, University of Bonn, Kreuzbergweg 26, D-53115 Bonn, Germany


A Suzuki cross-coupling reaction procedure was developed to prepare 8-substituted 3,7-dihydropurine-2,6-dione (xanthine) derivatives. 8-Halogen-substituted xanthines were reacted with phenyl- and styrylboronic acids. The best results were obtained using tetrakis(triphenylphosphine)palladium(0) and tripotassium phosphate in dimethylformamide. The developed procedure allows for a convergent synthesis of pharmacologically active 8-substituted xanthine derivatives.

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Paper | Regular issue | Vol 57, No. 5, 2002, pp. 881 - 894
Published online:
DOI: 10.3987/COM-02-9467
Synthesis of N-Oxydihydropyrrole Derivatives

Mitsuru Ito,* Hideshi Okui, Harumi Nakagawa, Shigeru Mio, Toshiaki Iwasaki, and Jun Iwabuchi

*Sankyo Co., Ltd., Agroscience Research Laboratories, 1041 Yasu, Yasu-cho, Yasu-gun, Shiga 520-2342, Japan


N-Oxydihydropyrrole derivatives were synthesized through an intramolecular Claisen condensation reaction. The N-acylation of hindered hydroxylamines played a key role in providing the useful intermediates, which could be converted to a variety of N-oxydihydropyrrole derivatives.

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Paper | Regular issue | Vol 57, No. 5, 2002, pp. 895 - 901
Published online:
DOI: 10.3987/COM-02-9469
Ring-Chain Tautomerism of Halogenated Phenolphthaleins: Vibrational Spectroscopic and Semiempirical MO Study

Ko-ki Kunimoto,* Hiromasa Sugiura, Toshiyuki Kato, Hitoshi Senda, Akio Kuwae, and Kazuhiko Hanai

*Kanazawa University, Faculty of Technology, Department of Chemistry and Chemical Engineering, Kakuma-machi, Kanazawa 920-1192, Japan


Ring-chain tautomerism of halogenated phenolphthaleins and the effect of the halogen substitution have been studied by vibrational spectroscopic and semiempirical MO methods. The vibrational spectra indicate that the content of the colored species (carboxylate form) increases on the substitution of the isobenzofuranone ring, whereas the colorless species (lactone form) becomes dominant on the substitution of phenolic rings. MO calculations have revealed that the substitution of either ring does not change the basic property of the electronic transition of the colored species and that the relative stability of both forms is dependent on the substitution type in accord with the results of the vibrational study.

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Note | Regular issue | Vol 57, No. 5, 2002, pp. 903 - 908
Published online:
DOI: 10.3987/COM-02-9458
A Synthesis of a Hydroxyvaline-derived Thiazole-4-carboxylate Constituting an Antibiotic, Thiocilline I

Yasuchika Yonezawa, Hirofumi Saito, Syusuke Suzuki, and Chung-gi Shin*

*Kanagawa University, Faculty of Engineering, Departmnet of Applied Chemistry, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan


A convenient synthesis of an important constituent segment, methyl (2S)-2-[1-(N-Boc)amino-2-hydroxy-2-methyl]propylthiazole-4-carboxylate (2), which is the Fragment C derivative of a macrocyclic antibiotic, thiocilline, is described. Reduction of methyl N-Boc-hydroxyvalinate (4) with NaBH4, followed by oxidation with Dess-Martin reagent gave the corresponding formyl derivative, which was then thiazolated with H-L-Cys-OMe to give 2.

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Note | Regular issue | Vol 57, No. 5, 2002, pp. 909 - 914
Published online:
DOI: 10.3987/COM-02-9468
Efficient N-Sulfenylation of Dihydropyrrole Derivatives Using N-Sulfenylphthalimides

Mitsuru Ito,* Hideshi Okui, Harumi Nakagawa, Shigeru Mio, Toshiaki Iwasaki, and Jun Iwabuchi

*Sankyo Co., Ltd., Agroscience Research Laboratories, 1041 Yasu, Yasu-cho, Yasu-gun, Shiga 520-2342, Japan


Ultrasound treatment of dihydropyrrole derivatives with N-sulfenylphthalimides in the presence of base gave the corresponding N-sulfenyldihydropyrrole derivatives.

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Review | Regular issue | Vol 57, No. 5, 2002, pp. 915 - 953
Published online:
DOI: 10.3987/REV-02-548
1,2-Oxazines and Their N-Oxides in Synthesis

Petros G. Tsoungas

*Department of Research and Technology, Ministry of Development, Messogion Ave. 14-18, GR-115 10, Athens, Greece


The potential of 1,2-oxazines towards diverse transformations, mainly of synthetic utility, is presented using selected examples.

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12 data found. 1 - 12 listed