HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Regular Issue
Vol. 38, No. 11, 1994
Published online:
■ Synthesis of 1,6-Anhydro-2-chloro-2,3,4-trideoxy-β-D-erythro-hex-3-enopyranose and Its Stereospecific SN2‘ Substitution
Masakatsu Matsumoto,* Hiromi Ishikawa, Yoshihiro Soya, and Takayuki Ozawa
*Department of Chemistry, Faculty of science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan
Abstract
The chlorination of 1,6--anhydro3,4-dideoxy-β-D-threo-hex-3-enopyranose (2) with SOCl2 and pyridine gives predominantly 1,6-anhydro-2-chloro-β-D-erythro-hex-3-enopyranose (3). The chloride (3) takes place exclusively the suprafacial SN2‘ substitution with a variety of nucleophiles in DMF. "Cerny epoxides" are conveniently synthesized by using the reaction of 3 with PhCH2ONa.
Published online:
■ Stereoselective Conversion of L-Quebrachitol into a Novel Hydroxylated Caprolactam: Total Synthesis of Bengamide B
Noritaka Chida,* Takahiko Tobe, Katsuyuki Murai, Kaori Yamazaki, and Seiichiro Ogawa*
*Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku, Yokohama 223-8522, Japan
Abstract
The stereoselective synthesis of the novel marine natural product, bengamide B (1), starting from L-quebrachitol (3) is described. The hydroxylated caprolactam portion (2a) in 1 was prepared from (+)-conduramine derivative (7), whose amino functionality was introduced stereoselectively by means of palladium-catalyzed azidation of a chiral cyclohexene (6) derived from 3.
Published online:
■ Halogenated Isoniazid Derivatives. Part 2. Unusual Synthesis of Δ2-1,3,4-Oxadiazoline Derivatives from Isonicotinoylhydrazones and Diazomethane
Rosaria Ottana, Enrico Rotondo, M. Gabriella Vigorita,* Carmela Zappala, and Gluseppe Giordano
*Dipartimento Farmaco-Chimico, Università di Messina, Viale Annunziata, 98168 Messina, Italy
Abstract
The synthesis of a representative group of isoniazid derivatives, namely 5-aryl-4-methyl-2-pryidyl-Δ2-1,3,4-oxadiazolines (3) and 4-aryl-1-methoxy-1-pyridyl-2,3-diazabutandienes (2) by reaction of isonicotinoylhydrazones (1) with diazomethane is described. A mechanism for the unexpected formation of 3 is suggested.
Published online:
■ Reactions of 16-Nitroindolenines of the Vincadifformine Type
Guy Lewin,* Yves Rolland, Corinne Schaeffer, and Jacques Poisson
*Laboratoire de Pharmaceutiques, Faculté de Pharmacie, Centre d‘Etudes et de Recherch sur le Medicament de Normandie, 1, ue Vaubénard, 14032 Caen Cedex, France
Abstract
The reactivity of 16-nitroindolenine (4), a byproduct of the aromatic nitration of vincadifformine (1), has been studied. In TFA 4 yielded 10-nitrovincadifformine (3) whereas acid hydrolytic treatment led to the tetracyclic oxindole structure (8) by cleavage of the 2-16 bond. Reduction of 4 (SnCl2 or hydrogenolysis) allowed recovery of 1 in good yield.
Published online:
■ Isolation of Two Limonoid Antifeedants from Melia toosendan
Munehiro Nakatani,* Jian-Bo Zhou, Tetsuo Iwagawa, and Hiroaki Okamura
*Department of Chemistry and Bioscience, Faculty of Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
Abstract
Two new limonoid antifeedants, trichilins I and J, were isolated from the stem bark of Melia toosendan (Meliaceae) and their structures were elucidated by spectroscopic means.
Published online:
■ Isolation of Two New Nitrogenous Metabolites from the Cultured Cells of Aspidosperma Quebracho-Blanco
Norio Aimi,* Naoki Uchida, Naoko Oya, Shin-ichiro Sakai, Luis A. Mendonza, Peter Obitz, and Joachim Stöckigt*
*Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
Abstract
Two novel nitrogen containing metabolites were isolated from cultured cells of Aspidosperma quebracho-blanco. Their structures were elucidated as 11-hydroxytubotaiwine and 1,6-propano-3-ethylideno-1,4-piperazine-2,5-dione.
Published online:
■ Synthesis of 4-Amino-7-hydroxybenzimidazole
Alan R. Katritzky,* Bogumila Rachwal, Stanislaw Rachwal, Peter J. Steel, and Krzysztof A. Zaklika
*BIOGAL Pharmaceutical Works, H-4042 Debrecen, Hungary
Abstract
A simple and efficient synthesis of 4-amino-7-hydroxybenzimidazole (2a) was developed involving condensation of 2,3-diaminophenol with triethyl orthoformate, coupling the 4-hydroxybenzimidazole (6) thus obtained with 4-ethylbenzodiazonium chloride to give 4-(4-ethylphenylazo)-7-hydroxybenzimidazole (7) and hydrogenolysis of 7 to give 2a. Acetylation of 2a with acetic anhydride gave triacetyl derivative (8), the structure of which was proved by X-ray crystallographic analysis.
Published online:
■ Molecular Rearrangements in Heterocyclic Synthesis. A Generalized Synthesis of 1,2,4-thiadiazoles from 3-Acylamino-1-oxa-2-azoles
Silvestre Buscemi and Nicolò Vivona*
*Dipartimento di Chimica Organica, Università digli Studi di Palermo, Via Archirafi 20 90123 Palermo, Italy
Abstract
The sulfuriaztion reaction of some 3-acylamino-1-oxa-2-azoles (1,2,4-oxadiazoles, isoxazoles and 1,2,5-oxadiazoles) with the Lawesson reagent has been investigated. A generalized methodology for the synthesis of 5-aryl-/alkyl-3-substituted 1,2,4-thiadiazoles via molecular rearrangement of the corresponding thioamides has been pointed out.
Published online:
■ N-Substituted Bromopyrazoles: Synthesis and 13C Nmr Study
Wolfgang Holzer,* Christine Jäger, and Christoph Slatin
*Institute of Organic Chemistry, University of Graz, Heinrichstr. 28, A-8010 Graz, Austria
Abstract
The synthesis of N-1 substituted 4-bromo-, 3,4-dibromo- and 3,4,5-tribromopyrazoles starting from the NH-pyrazoles is described. 13C Nmr spectroscopic studies with the title compounds are presented, investigating the influence of substituents on 13C-chemical shifts and 13C, 1H spin coupling constants.
Published online:
■ Synthesis and Solvatochromic Behavior of Stilbazolium Merocyanine-Type Dyes Having a Benzo[c]quinolizinium Ring
Sadao Arai,* Hitoshi Arai, Mitsuhiko Hida, and Takamichi Yamagishi
*Department of Industrial Chemistry, Faculty of Technology, Tokyo Metropolitan University, 1-1, Minami-ohsawa, Hachioji, Tokyo 192-0364, Japan
Abstract
A series of stilbazolium merocyanine-type dyes, 3[2-(hydroxy-substituted aryl)vinyl]benzo[c]quinolizinium perchlorates, was synthesized by the aldol-type condensation of 3-methylbeno[c]quinolizinium perchlorate with hydroxy-substituted benzaldehyde derivatives in 45-85% yields. The deprotonated from of the dyes exhibited the pronounced negative solvatochromism extended almost over the whole visible region. The negative solvatochromic character of the dyes having a benzo[c]quinolizinium ring was more striking than that of the isomeric dyes having a benzo[a]quinolizinium ring.
Published online:
■ A New Synthetic Route to Functionalized 2-Azabicyclo[2.2.2]octane
Morio Asaoka,* Naoto Ohkura, Masaru Yokota, Syuzo Sonoda, and Hisashi Takei
*Department of Life Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Instituteof Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
Abstract
Functionalized 2-azabicyclo[2.2.2]octane ring system was prepared via intramolecular SN2 ring opening of epoxide by an amide anion.
Published online:
■ An Alternative Route to a Benzofuran Natural Product Dehydrotremetone
Kou Hiroya, Kazuya Hashimura, and Kunio Ogasawara*
*Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai 980-5878, Japan
Abstract
Dehydrotremetone, a toxic ketone isolated from the weeds Eupatorium urticaefolium and Aplopappus heterophyllus, has been synthesized from isovanillin via palladium-mediated cross-coupling reaction and lithium chloride-mediated concurrent demethylation-benzofuran formation reaction. The present procedure also allows a simple preparation of three other non-heterocyclic acetylenic phytotoxic compounds isolated from the culture medium of Eutypa lata.
Published online:
■ Diterpenoids from Salvia paramiltiorrhiza
Hou-Wei Luo,* Xiao-Ru Sun, and Masatake Niwa
*Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tenpaku, Nagoya 468-8503, Japan
Abstract
Six diterpenes including a novel compound named paramiltioic acid were isolated from Salvia paramiltiorrhiza LI et Huang. Their structures were characterized by physical methods.
Published online:
■ Reaction of Pentachloropyridine 2,3,4,5-Tetrachloro-4-pyridyllithium with α-Lithiated Arylacetonitriles and N-Butyllithium
Edward R. Biehl,* Hala Mohammed Rafat, and A. A. Fadda
*Department of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, TX 75275-0314, U.S.A.
Abstract
Perchloropyridine (1) reacts smoothly at -70 °C with α-lithioarylacetonitriles (3) affording α-(aryl)-2,3,5,6-tetrachloro-4-pyridylacetonitriles (4). The 2,5,6-trichloro-3,4-dehydropyridine precursor, 2,3,5,6-tetrachloropyridyllithium (5), reacts similarly at -70 °C with 3, but instead of providing 3,4-dehydropyridine products, α-(aryl)-2,3,4,5-tetrachlorophenylacetonitrile supplies mainly 4 and α-(aryl)-3,5,6-trichloro-2-pyridylacetonitriles (6) plus minor quantities of α-(aryl)-3,4,5,6-tetrachloro-2- (7) and α-(aryl)-2,4,5,6-tetrachloro-3-pyridylacetonitriles (8). The product ratios of 4 to 6 from these reactions as well as the relative yields of 4 from the reaction of 1 and 5 with 3 are highly dependent upon 3. To account for these results, an explanation in terms of competing lithium-chlorine exchanges between 1 or 5 with 3 of α-chloroarylacetonitriles (9) is proposed.
Published online:
■ Synthesis and Reactions of Lithiated Monocyclic Azoles Containing Two or More Hetero-Atoms Part IV: Imidazoles
Brian Iddon* and Raphael I. Ngochindo
*Department of Chemistry and Applied Chemistry, The Ramage Laboratories, University of Salford, Salford M5 4WT, U.K.
Abstract
The metallation and halogen —> metal exchange reactions of imidazoles (1,3-diazoles) and the reactions of the resulting organometallic derivatives, particularly lithiated derivatives, are reviewed comprehensively.