HETEROCYCLES

■ Synthesis of σ-Tris-homoazepine Skeleton

Tadashi Sasaki,* Ken Kanematsu, and Yusuke Yukimoto

*Institute of Applied Organic Chemistry, Faculty of Engineering, Nagoya University, Chikusa, Nagoya, Aichi 464-8601, Japan

Abstract

Addition of dichlorocarbene in aqueous medium (phase transfer method) to N-ethoxycarbonyl-1(lH)-azepine gave all-trans-N-ethoxycarbonyl-l(lH)-σ-tris-homoazepine derivative in a highly stereospecific manner.

■ Studies on Indole Alkaloid Biosynthesis. VIII. The Later Stages of the Biosynthesis of Apparicine

James P. Kutney,* John F. Beck, and George B. Fuller

*Department of Chemisry, University of British Columbia, Vancouver 8, V5T 1W5, Vancouver 8, V5T 1W5

Abstract

Biosynthetic experiments with Aspidosperma pyricollum plants employing radioactively labelled forms of 16, 17-dihydrosecodin-17-ol (2) and secodine (3) reveal that the latter is incorporated intact during the biosynthesis of apparicine (1). These results provide important information about the later stages of biosyntheses of this alkaloid.

■ Studies on Indole Alkaloid Biosynthesis IX. The Later Stages of Iboga Alkaloid Biosynthesis

James P. Kutney* and Nigel J. Eggers

*Department of Chemisry, University of British Columbia, Vancouver 8, V5T 1W5, Vancouver 8, V5T 1W5, Canada

Abstract

Biosynthetic experiments with Vinca rosea L. plants employing radioactively labelled forms of secodine (I) reveal that this substance is incorporated intact during the biosynthesis of catharanthine (II). These results provide some information about the later stages of biosynthesis of this alkaloid.

■ Total Synthesis of (±)-Sinactine and (±)-Cavidine (Base II)

Ichiya Ninomiya,* Hisashi Takasugi, and Takeaki Naito

*Kobe Women’s College of Pharmacy, Motoyamakita, Higashinad, Kobe, Hyogo658, Japan

Abstract

Sinactine (VIa) and cavidine (VIb) were synthesized by a route which included enamide photocyclization.

■ The Photodimerization of Naphthofurazan

Makoto Nitta and Toshio Mukai*

*Department of Chemistry, Faculty of Science, Tohoku University, Aoba-ku, Ssendai 980-8578, Japan

Abstract

Irradiation of naphtho[1,2-c]furazan (I) afforded two photodimers (II) and (III) accompanied by fragmentation products. The structure of the dimers was assigned on the basis of the solvent dependency for the dimerization as well as the degradation reactions of the dimers. In addition, it was suggested that the photodimerization took place via a triplet state of I.

■ An Analogue of Corynoline

Masayuki Onda,* Yumiko Yuasa, and Junko Okada

*School of Pharmaceutical Sciences, Kitasato University, 5-9-1, Shirokane, Minato-ku, Tokyo 108-8641, Japan

Abstract

The analogue VIII of corynoline, which contains methoxyl groups at C-7 and C-8 instead of a methylenedioxy group, has been synthesized from the ψ-cyanide I.

■ The Synthesis of (±)-Thalphenine, Thaliglucine and Thaliglucinone

Maurice Shamma* and Der-Yan Hwang

*Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, U.S.A.

Abstract

Photolysis of the phenolic tetrahydrobenzylisoquinoline 11 yielded de-N-methylthalphenine (14). Quaternization with methyl iodide then afforded thalphenine iodide (rac. 1) which upon Hoffman elimination supplied thaliglucine (2).

■ Chemistry of Nitroimines. V. Reaction of 3-Substituted 2-Nitrosoimine-2,3-dihydrobenzothiazoles with Lithium Aluminum Hydride

Kin-ya Akiba, Takayuki Kawamura, Masahide Ochiumi, and Naoki Inamoto*

*Department of Chemistry, Scool of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

Abstract

Reaction of 3-substituted 2-nitrosoimino-2,3-dihydrobenzothiazoles with lithium aluminum hydride gave corresponding thiazolone azines and bis [o-(N-substituted N-formylamino)phenyl] disulfides as major products.

■ Selective Reduction of 12-Oxa[4.4.3]propella-2,4,7,9-tetraene Catalyzed by an Arenechromium Tricarbonyl

Chaim Amith, Michael Cais,* Dan Fraenkel, and David Ginsburg*

*Department of Chemistry, Israel Institute of Technology, Haifa 32000, Israel

■ Synthesis of 2-[N-(2-Methyl)propanoyl]-N-phenylethylglutarimide

David McNeill and Kenneth L. Stuart*

*Department of Chemsitry, University of the West Indies, Mona, Kingston 7, Jamaica

Abstract

The structure of the glutarimide peptide (I) isolated from Croton humilis has been confirmed by synthesis.

■ Catalytic Hydrogenation of (±)-Kreysiginone

Tetsuji Kametani,* Fumio Satoh, Keiichiro Fukumoto, Hideo Sugi, and Kazuo Kigasawa

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

Abstract

Catalytic hydrogenation of the isomerc homoproaporphines (Va and Vb) and the deuterated dienones VIa and VIb in the presence of platinum afforded the same mixture of cyclohexanols (VIIa and VIIb). In contrast, palladium reduction of the hydrochloride of Va provided the cyclohexanone (VIIIa) while that of Vb gave a mixture of the cyclohexanone (VIIIb) and the cyclohexenone (IX).

■ Influence of the Heterocyclic Base-component on the Reaction of Enamines with Allylic Halides

Pieter Houdewind, Upendra K. Pandit,* Ajay K. Bose, Raymond J. Brambilla, and George L. Trainor

*Organic Chemistry Laboratory, University of Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands

Abstract

Pyrrolidine, piperidine and morpholine enamines of cyclohexanone (la-c) react with allylic halides to give mixtures of isomeric alkylated products in which the isomer-ratio can be correlated with the chemical shifts ( ¹H and ¹³C) of the β-carbon of the enamines.

■ A General Procedure for the Synthesis of Epoxy-alkylated and Acylated Heterocycles

Edward C. Taylor,* Michael L. Chittenden, and Stephen F. Martin

*Department of Chemistry, Princeton University, Princeton, New Jersey 08544, U.S.A.

■ Merostabilisation — A New Principle Governing the Stability of Organic Free Radicals

Roger W. Baldock, Paul Hudson, Alan R. Katritzky,* and Ferenc Soti

*School of Chemical Sciences, University of East Anglia, Norwich, Northfolk NR4 7TJ, U.K.

Abstract

The concept of merostabilisation is discussed which predicts enhanced stability for those free radicals in which low energy zwitterionic canonical forms can contribute to the resonance hybrid. The principle has been used to predict the existence of several novel stable radicals which have been synthesised.

■ Partial Ether Cleavage of Methoxy and Methylenedioxy-substituted Isoquinoline Alkaloids

Sidney Teitel* and Arnold Brossi

*The Department of Chemistry Research, Hoffman-La Roche Inc., Nutley, New Jersey 07110, U.S.A.

Abstract

A variety of polymethoxy-substituted isoquinolines have been preferentially O-demethylated with mineral acid and the procedure applied to the facile synthesis of the alkaloids corypalline (46), cherylline (48), multifloramine (51), anhalonine (2) and lophophorine (54). The method of selective O-demethylenation of methylenedioxy-dimethoxy-substituted isoquinolines with boron trichloride was utilized for the conversion of the phthalide alkaloid (-)-β-hydrastine (6) into (-)-cordrastine II (7).

■ Syntheses of Isoquinoline Alkaloids by a Systematic Design

Tetsuji Kametani* and Keiichiro Fukumoto

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

Abstract

The synthetic design of isoquinoline alkaloids from simple compounds derived by systematic retro-synthesis and transformation by either phenolic oxidation, Pschorr reaction, photolytic reaction, benzyne reaction, or thermolysis are described.

■ Application of Reissert Compounds to the Total Synthesis of Isoquinoline Alkaloids and Related Compounds

Frank D. Popp*

*Department of Chemistry, Clarkson College of Technology, Potsdam, New York 13676, U.S.A.

Abstract

N-Acyldihydroisoquinaldonitriles (isoquinoline Reissert compounds) have been used as the key intermediates in the synthesis of a wide variety of isoquinoline alkaloids.

■ Electro-oxidation and Isoquinoline Alkaloid Biosynthesis

James M. Bobbitt*

*Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, U.S.A.

Abstract

Phenol oxidation is one of the major organic reactions used in nature for the production of various metabolites, both primary and secondary, and is especially important in the biosynthesis of the isoquinoline alkaloids. Electro-oxidation, can be more precisely controlled than any of the many known oxidation methods and, furthermore, is a heterogeneous reaction with the possibility of surface phenomena. In this article, those areas in which electro-oxidation has been, or may be, used to study biomimetic syntheses of the isoquinoline alkaloids will be summarized.