HETEROCYCLES

■ Elaeocarpus Alkaloids. The Synthesis of (±)-Elaeokanine A, (±)-Elaeokanine B, and (±)-Elaeokanine C

Toshio Watanabe,* Yoshihiko Nakashita, Sadamu Katayama, and Masashige Yamauchi

*Faculty of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan

Abstract

The synthesis of (±)-elaeokanines A, B and C by using compound 2 as an intermediate is described.

■ An Efficient Reduction of Nitriles and Amides to the Corresposnding Amines with Tetra-N-butylammonium Borohydride in Dichloromethane

Takeshi Wakamatsu,* Harumi Inaki, Akemi Ogawa, Masako Watanabe, and Yoshio Ban

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

Abstract

The reduction of nitriles and amides to the corresponding amines with tetra-n-butylammonium borohydride in dichloromethane has been reported, in which the other functional groups such as ester, nitro, and halogen attached to the aromatic ring are not affected.

■ The Use of Tetra-N-butylammonium Borohydride for the Reduction of Indoles to Indolines in Dichloromethane

Takeshi Wakamatsu,* Harumi Inaki, Akemi Ogawa, Masako Watanabe, and Yoshio Ban

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

Abstract

Several indole compounds were reduced with tetra-n-butylammonium borohydride in dichloromethane to the corresponding indolines under mild conditions, in which solvent most of indole compounds are easily soluble.

■ Reaction of Pyridinium Disubstituted Methylides with Diphenylcyclopropenethione

Kiyoshi Matsumoto* and Yukio Ikemi

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

Abstract

Diphenylcyclopropenethione undergoes nucleophilic attack by pyridinium disubstituted ylides (1a-e) to produce the corresponding indeno-2-thiopyrone (3), 2-pyrone (5 or 10), 1-thio-2-pyrone (6, 8, 11, or 12), and/or 2-thiopyrone (4) derivatives.

■ Formation of 3,5-Dicyano-4-(N,N-dimethylformamidino)-2,6-diphenyl-4H-pyran from ω-Cyanoacetophenone

Syoji Morimura*

*Central Research Laboratories, Sankyo Co.,Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140 Japan

Abstract

A 4H-pyran derivative, 3,5-dicyano-4-(N,N-dimethylformamidino)-2,6-diphenyl-4H-pyran (9) was obtained by the reaction of [N-(dimethylaminomethylene)aminomethylene] dimethylammonium chloride (5) with ω-cyanoacetophenone (8).

■ A Novel Synthesis of (±)-Fumaricine

Miyoji Hanaoka,* Shingo Yasuda, Yuriko Hirai, Kazuyoshi Nagami, and Takeshi Imanishi

*Faculty of Pharmaceutical Scicences, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan

Abstract

A novel synthesis of (±)-fumaricine (9) from the phenolbetaine (5) via the 8,14-cycloberbine (6), the photochemical valence tautomer of 5, is described.

■ Synthetic Approaches to Catharanthine, Isoxazolidine as a Potential Intermediate

Ratremaniaina Z. Andriamialisoa, Nicole Langlois, and Yves Langlois*

*Institut des Chimie des Substances Naturelles, C.N.R.S., 1 avenue de la Terrasse, Bat. 27, 91198 Gif-sur-Yvette Cedex, France

Abstract

The preparation of catharanthine 3 from isoxazolidine 5 shows that this latter compound could be a good target in total synthesis.

■ Structure of Moracenin C, a Hypotensive Principle of Morus Root Barks

Yoshiteru Oshima, Chohachi Konno, Hiroshi HIkino,* and Kazuhiro Matsushita

*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan

Abstract

From the crude drug “sohakuhi”, the root barks of Morus plants, a novel isoprenoid flavone, moracenin C, having hypotensive activity has been isolated and the gross structure has been determined as represented by formula I (exclusive of stereochemistry). The absolute stereostructures of moracenin A, B and C have been deduced on the basis of physico-chemical evidence.

■ Tripdiolide from Tissue Culture of Tripterygium wilfordii

James P. Kutney,* Michael H. Beale, Phillip J. Salisbury, Robert D. Sindelar, Kenneth L. Stuart, Brian R. Worth, Phillip M. Townsley, William T. Chalmers, Danielle J. Donnelly, Kristina Nilsson, and Giulio G. Jacoli

*Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, B.C., V6T 1Z1, Canada

Abstract

Shake flask cultures of plant tissue cells from Tripterygium wilfordii have yielded the cytotoxic compounds tripdiolide and celastrol.

■ Carbon-13 NMR Analysis of Some 4-Quinazolinone Alkaloids and Related Compounds

J. Bhattacharyya* and S. C. Pakrashi

*Department of Chemistry, Clemson University, Clemson, SC 29631, U.S.A.

Abstract

Carbon-13 NMR Spectra of some 4-quinazolinones, which indicate the predominent tautomeric forms of these compounds, have been determined.

■ The 6th Colloquium of Heterocyclic Chemistry, Mulhouse, July, 1-3, 1980

*,

■ Total Synthesis of d,l-Saxitoxin

Yoshio Kishi*

*Department of Chemistry, Harvard University, 12 Oxford Street, Cambridge, Massachysetts 02138, U.S.A.

■ New Approaches to Heterocycles via Nitrenes

Otto Meth-Cohn*

*Department of Chemistry and Applied Chemistry, The Ramage Laboratories, University of Salford, Salford M5 4WT, U.K.

Abstract

Nitrenes derived from 2-azidophenyl aryl sulphides, 2-azidophenyl aryl ketones, aryl 2-azidobenzoyl esters and aryl or arylalkyl azidoformates have been cyclised to yield a wide variety of novel heterocycles.

■ Azirines as Synthons for Other Heterocycles

Alfred Hassner*

*Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13901, U.S.A.

■ 1,3-Dipolar Cycloadditions with Dipoles or Dipolarophiles to Masked Groups. Preparation of Electrophilic and/or Functionallised Cyclopropanes, Racemic or Chiral

par R. Carrié*

*Groupe de Recherches de Physicochimie Structurale, Université de Rennes I, Campus de Beaulieu 35042 Rennes Cedex, France

■ Heterocycles from 1,2- and 1,4-Cycloadditions to Ketenimines

Alessandro Dondoni*

*Dipartimento di Chimica, Laboratorio di Chimica Organica, Università degli Studi di Ferrara, Via Fossato di Mortara 17-19, I-44100 Ferrara, Italy

Abstract

Cycloadditions of thiobenzophenone to ketenimines illustrate the possibility of multiple modes of reaction across various centres of the cumulene depending on the substituents at nitrogen and carbon as well. 1,2-Cycloaddition across the C=C bond of the cumulene to give iminothietanes, as well as two types of 1,4-cycloaddition, one involving the C=N bond of the cumulene and the N-aryl group to give benzothiazines, the other involving the C=C bond of the cumulene and the C-vinyl to give iminothiacyclohexenes, have been observed. The variable siteselectivity in ketenimine-thioketone cycloadditions appears to be determined by a balance between steric and electronic effects, the latter being interpreted in terms of frontier MO’s of the cumulene. Cycloadditions of electron-poor heteroenes (tosylisocyanate, N-dicyanomethylene-p-chloroaniline, sulfur dioxide) offer other examples of variable siteselectivity which produce four- and six-membered heterocycles. On the other hand, vinylketene although more reactive than vinylketenimine, appears to undergo exclusively 1,2-cycloaddition across the C=C bond of the cumulene to give four-membered adducts. The possibility of stereochemical variables in ketenimine cycloadditions increases the value of these heterocumulenes as intermediates for the synthesis of heterocycles.

■ Application of Enamide Chemistry to the Synthesis of Heterocyclc Compounds

Ichiya Ninomiya*

*Kobe Women’s College of Pharmacy, Motoyamakita, Higashinad, Kobe, Hyogo 658, Japan

Abstract

Photochemical and thermal reactions of enamides with respect to the synthetic application to heterocycles are reviewed. Enamides, N-α,β-unsaturated acylenamines, undergo cyclization under not only photochemical but also thermal conditions to afford a wide variety of hetcrocyclic compounds, thus proving enamides as potential synthons for the construction of heterocycles.

■ Isonitrosotosylate Derivatives in the Malonate Series, Polyvalent Reagents for the Synthesis of Nitrogen-Heterocycles

Jean-Pierre Fleury*

*Ecole Nationale Superieure de Chimie de Mulhouse, Université de Haute Alsace, 3, rue A. Werner, 68096 Mulhouse Cedex, France

■ Electroorganic Syntheses of Nitrogen-Heterocycles

Wolfgang Pfleiderer* and Raphael Gottlieb

*Fakultät für Chemie, Universität Konstanz, Posttach 5560, D-7750 Konstantz, Germany

■ Preparation and Use of Nitrogen- or Sulphur containing Heterocycles in Organic Synthesis

Wolfgang Oppolzer*

*Department of Organic Chemistry, Laboratory fo Crystallography, University of Geneva, 30, quai Ernest Ansermet, 1211 Geneva 4, Switzerland

Abstract

The utility of intramolecular cycloadditions of ortho-quinodimethanes for the synthesis of complex polycyclic molecules is illustrated: 1) by the stereoselective synthesis of the natural alkaloid (±)-chelidonine starting from a benzocyclobutene; 2) by the efficient preparation of various polycyclic carbon skeletons using 1,3-dihydroisothianaphthen-2,2-dioxide as a simple building block. Furthermore, the total syntheses of the ergolines chanoclavine I and isochanoclavine I, exploiting a regio- and stereo-selective intramolecular nitrone-olefin-addition, is described.

■ Cyclic Phosphinates, Oligomerisation, Preparation of Polyphosphorus Macrocycles, Stereochemical and NMR Studies

J. P. Dutasta, J. Martin, and J. B. Robert*

*Ledss/UMR 5616, Laboratoire d’Etudes Dynamiques et Structurales de la Sélectivité, Université Joseph Fourier, 38041 Grenoble cédex 9, France

Abstract

Les phosphonites cycliques à cinq, six, sept et huit chainons, peuvent évoluer en solution pour donner les formes dimères cycliques correspondantes. Cette réaction peut être étendue à d’autres hétérocycles du type dithia-1,3 ou oxaza-1,3. Quelques résultats sont présentés sur la stéréochime des monomères cycliques à huit chainons.

■ Heterocycles via ortho-Lithiated Benzamides

Victor Snieckus*

*Guelph-Waterloo Centre for Graduate Work in Chemistry, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada

Abstract

Ortho-lithiated N,N-diethyl benzamides, readily generated by treatment of the corresponding amides with sec-BuLi or t-BuLi in THF or Et₂O/TMEDA at -78°, are important new synthons (d₃-reagents) for the regiospecific construction of highly substituted aromatic derivatives which are difficult to obtain by classical (usually electrophilic substitution) chemistry (Scheme 1). This paper will demonstrate the utility of ortho-lithiated benzamides for the synthesis of contiguously substituted aromatics, phthalide and isochroman-1,3-dione heterocycles, phthalideisoquinoline alkaloids, anthraquinone natural products, polycyclic anthraquinones and corresponding PAH’s, heterocyclic benzoquinones, and ellipticine alkaloids.

■ Some Recent Advances in the Synthesis of Three-Membered Ring Heterocycles

Helmut Quast*

*Institut für Organische Chemie, Universität Wurzburg, Am Hubland D-97074 Wurzburg, Germany

Abstract

The syntheses of some three-membered rings containing phosphorus(V) or sulfur(Vl) and of nitrogen analogs of methylene-cyclopropane, viz. methylenaziranes, iminoaziranes, and imino-diaziranes, are reviewed. Furthermore, an account is given of the photo-extrusion of nitrogen from 1-pyrazolines and tetrazolines both having exocyclic double bonds, which in most cases leads to the formation of methylenecyclopropane analogs.

■ Furan Synthesis

Ernest Wenkert*

*Department of Chemistry, Rice University, Houston, Texas 77251, U.S.A.

Abstract

The use of dimethyl diazomalonate in copper-catalyzed cyclopropanations of enol ethers led to intermediates readily convertible into β-methylfuran, α-methylene-γ-lactone and β-methylene-γ-lactone units common among terpene structures and to a synthesis of menthofuran. The copper-induced interaction of enol ethers with ethyl diazopyruvate yielded oxydihydrofuroic esters from which α-furoic acids, furans and the common α-isopropylfuran terpene structure could be constructed. A similar reaction of diazopyruvic ester with acetylenes produced α-furoates directly. The Fétizon oxidation of β-oxycyclopropyl carbinols has been shown to give oxydihydrofurans, an observation on which another menthofuran synthesis was based. The copper-assisted decomposition of diazobiacetyl monoketal in n-butyl vinyl ether afforded a cyclopropane whose treatment with methanolic acid afforded veratrole. This unusual benzene ring construction was utilized in a new synthesis of hydrourushiol.