HETEROCYCLES

■ A Simple Synthesis of Isopavine Alkaloid, (±)-O-Methylthalisopavine and (±)-Reframine

Osamu Hoshino, Michinori Taga, and Bunsuke Umezawa*

*Faculty of Pharmaceutical Sciences, Science University of Tokyo, 12 Funakawaramachi, Shinjuku-ku, Tokyo 162, Japan

Abstract

(±)-O-Methylthalisopavine (I) and (±)-reframhe (II) were synthesized by acid treatment and subsequent methylation of (±)-4-acetoxytetrahydroisoquinoline [(V) and (VI)) directly derived from 6-hydroxytetrahydroisoquinoline [ (III) and (IV)].

■ Ring Contraction of 2-Azidoquinoline- and Quinoxaline-1-oxodes

Rudolph A. Abramovitch* and Berkeley W. Cue, Jr.

*Department of Chemistry, University of Alabama, Box 870336, University, Tuscaloosa, Alabama 35478-0336, U.S.A.

Abstract

2-Azidoquinoline-1-oxide undergoes thermal ring-opening, intermolecular nucleophilic addition and ring contraction to give 2-aminoquinoline-1-oxide, 2-cyanoisatogen (4), and 2,2’-dicyano- 3,3’-bisindole (5). If the 4-position in the quinoline is blocked then the expected ring-contractions take place: 2-azidolepidine-1-oxide gives 2-cyano-N-hydroxy-3-methylindole, while 2-azidoquinoxaline-1-oxide gives 2-cyano-1-hydroxybenzimidazole. Syntheses of authentic 4 and 5 are reported.

■ Reaction of Chloropicoline 1-Oxides in Liquid Ammonia in the Presence of Potassium Amide

Tetsuzo Kato* and Takuitsu Niitsuma

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

Abstract

Amination of chloropicoline 1-oxides with potassium amide in liquid ammonia is described.

■ Oxidation of Pyrroles with Benzoyl Peroxide

Masato Aiura and Yuichi Kanaoka*

*Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan

Abstract

Upon treatment with benzoyl peroxide 1, N-substituted pyrroles 2 afforded 2-benzoyloxy- 3 and 2,5-dibenzoyloqxypyrroles 4. N-Substituted pyrrole-2-carbinols 5 undergo novel C-C cleavage with 1 to also give 3 and 4.

■ The Reaction of Quinoline N-Oxide with N,N-Diethylthiocarbamoyl Chloride

Masatomo Hamana* and Keiji Muraoka

*Faculty of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan

Abstract

Quinoline N-oxide (I) reacted with N,N-diethylthiocarbamoyl chloride (II) at room temperature to give S-2-quinolyl N,N-diethylthiocarbamate (III) and O-3-quinolyl N,N-diethylthiocarbamate (IV). From reactions in the presence of a base, S-3- (VII) and S-8-quinolyl N,N-diethylthiocarbamates (VIII) were formed besides III and IV. The possibility of a new mechanism for the formation of III was suggested.

■ Synthesis of Corgoine

Tetsuji Kametani,* Keiichi Takahashi, Chu Van Loc, and Michiyo Hirata

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

Abstract

Corgoine (I) was synthesized by two different methods, which proved the suggested structure to be correct. The biogenesis of the 2-benzylisoquinoline alkaloids is also discussed.

■ A New Route to Pyrrolo[2,3-b]indoles

Noboru Shoji, Yoshikazu Kondo,* and Tsunematsu Takemoto

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

Abstract

The cyclization of 3-hydroxy-3-2’-hydroxyiminooxindoles (1) to pyrrolo[2,3-b]indole derivatives (2-5) has been described. In the resulting products, 4 and 5 were first isolated five-membered invertomers.

■ Benzo- and Indoloquinolizine Compounds. IV. The Use of ¹³C-H Coupling Constants in the Stereochemical Study of Nitrogen Bridgehead Compounds

Georges Van Binst* and Dirk Tourwe

*Laboratoium voor organische Chemie, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium

Abstract

The preferential cis or trans quinolizidine conformation has been determined by measurement of the 13C-H coupling constants of the C-H bonds next to the bridgehead nitrogen in benzo- and indoloquinolizidine compounds I - V.

■ Arene Oxides-Oxepins

Donald M. Jerina,* Haruhiko Yagi, and John W. Daly

*Laboratory of Chemistry, Metabolism and Digestive Diseases, National Institute of Arthritis, National Institute of Health, Bethesda, Maryland 20014, U.S.A.

■ Synthesis of Androcymbine and Related Homomorphinandienones

Tetsuji Kametani,* Keiichiro Fukumoto, and Masuo Koizumi

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

Abstract

The synthesis of the homomorphinandienones by several methods are discussed. The total synthesis of the homomorphinandienone alkaloids androcymbine and O-methylandrocymbine by a photo-Pschorr reaction or photo-cyclodehydrohalogenation are described.