HETEROCYCLES

■ Synthesis and Some Reactions of o-Nitrosoaniline

Makhluf J. Haddadin,* Halim E. Bitar, and Costas H. Issidorides

*Department of Chemistry, American University of Beirut, Beirut, Lebanon

Abstract

A simple synthesis of o-nitrosoaniline is reported. This compound reacts with some enolate anions, glyoxals, and substituted phenolate anions to give quinoxalines, 1-hydroxy-2-quinoxalinones, and phenazines respectively.

■ Benzo- and Indoloquinolizidines. Part XVIII. The Preparation of 4b,5,6,7,7a,10,14b-Octahydrodibenzo[a,h]cyclopenta[c]quinolizine Isomers. An Application of Stereoselective Iminium Cyclistations

F. Vlaeminck and G. Van Binst*

*Service de Chimie Organique, Faculté des Sciences Appliquées (CP165), Université Libre de Bruxelles, 50 Avenue F. D. Roosevelt, 1050 Brussels, Belgium

■ 2-Demethylcolchifoline — A New Alkaloid from Colchicum autumnale L

Petr Sedmera,* Helena Potesilová, Vladimíra Malichová, Vladimír Preininger, and Frantisek Santavy

*Medical Faculty, Institute of Medical Chemistry, Palacky University, Hnevotínská 3, 77515 Olomouc, Czech Republic

Abstract

The structure of 2-demethylcolchifoline (IV), isolated from leaves of Colchicum autumnale L., has been determined on the basis of mass spectrometry, ¹H NMR and ¹³C NMR spectroscopy.

■ 3-Azanoradamantanes

Theo Reints Bok and W. Nico Speckamp*

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

Abstract

3-Azanoradamantanes 1-3 are obtained by ring closure in acid medium of C₇-substituted N-tosyl-3-azabicyclo[3.3.1]nonanes. The basicity of 1-3 and the behaviour in the near UV region of 2 and 3 are discussed.

■ An Oxazole and Its Precursor in Amyris balsamifera

Basil Burke,* Helen Parkins, and Ann Marie Talbot

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

Abstract

The discovery of the oxazole, balsoxin (6), and the β-hydroxy-β-phenylethylamide, balsamide (4), constitutes further evidence for the biogenetic relationship between these types of compounds. The structures and correlation of these compounds are presented.

■ Quinazolinocarboline Alkaloids Chemistry: Reactivity of Euxylophorines — Part 1

Bruno Danieli, Giordano Lesma, and Giovanni Palmisano*

*Istituto di Chimica Organica, Facoltà di Farmacia, Università degli Studi di Milano, Via Venezian 21, I-20133 Milano, Italy

Abstract

The quinazolinocarboline alkaloids of type (1a) and (1b) showed a marked regioselectivity towards nucleophilic reagents, (1a) reacting at C_13b-N₁₄ bond while (1b) cleaving the C₅-N₆ bond. The catalytic hydrogenation was also reported.

■ C-Glycosyl Nucleoside XVII. A Novel Reaction of Schiff Bases with Mercuric Chloride in Dimethyl Sulfoxide

Haruo Ogura,* Masakazu Sakaguchi, Toshihiko Okamoto, Kinji Gonda, and Shozo Koga

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

Abstract

Pteridine or theophylline derivatives were obtained from the reaction of Schiff bases of 5,6-diamino-1,3-dimethyluracil with HgCl₂ in dimethylsulfoxide via radical or ionic mechanisms which were confirmed by the studies of time dependent ESR and NMR spectra. These reactions are useful for the preparation of nucleoside analogs.

■ Studies of Pyrazines. IV. Pyrolysis of 2-Alkoxypyrazines

Takeo Konakahara,* Kazuhiko Kuwata, and Yukio Takagi

*Department of Industrial Chemistry, Faculty of Science and Technology, Science University of Tokyo, 2641 Yamazaki, Noda, Chiba 278-8510, Japan

Abstract

A pyrolysis of 2-alkoxypyrazine (1) has been performed to give 2-pyrazinol (2) and alkene (3) and to obey first-order kinetics. The reaction proceeds through a 6-membered cyclic transition state analogous to that of ester pyrolysis. The activation parameters, log(A/s^-1) and E_a/(kcal mol^-1), and the relative rate constants were determined in the pyrolysis of eight 2-alkoxypyrazines 1 (R = C₂H₅, n-C₃H₇, i-C₃H₇, i-C₄H₉, s-C₄H₉, t-C₄H₉, t-C₅H₁₁, and 1,2-dimethylpropyl). Substitution effects on the reaction rate at the α- and β-position in the alkoxyl group were discussed on the basis of the kinetic data.

■ Application of Carbonyl Umpolung to Prostaglandin Synthesis II. Synthesis of the Intermediates of (±)-11-Deoxyprostaglandins F_1α and F_2α, and Prosraglandin F_2α

Lajos Novák,* Béla Majoros, and Csaba Szántay

*Institute for Organic Chemistry, Technical University Budapest, H-1521 Budapest, P.O. Box 91Gellért tér 4, Hungary

Abstract

The intermediates of prostaglandins have been synthesized from 2-cyclopenten-1-one derivatives by a novel thiazolium ion-catalysed acylation.

■ Studies of Pyrazines. V. Preparation of 2-Alkylpyrazines from Alkyl 2-Pyrazinyl Sulfones

Takeo Konakahara,* Kyoichi Gokan, Masahiro Iwama, and Yukio Takagi

*Department of Industrial Chemistry, Faculty of Science and Technology, Science University of Tokyo, 2641 Yamazaki, Noda, Chiba 278-8510, Japan

Abstract

The pyrolysis of 10 alkyl 2-pyrazinyl sulfones was performed to give 2-alkylpyrazines, pyrazine, and sulfur dioxyde with some tarry products. The primary alkyl 2-pyrazinyl sulfones (R = n-C_nH_2n+1; n = 1 ~ 5 and i-C₄H₉) gave the corresponding 2-alkylpyrazines as the major product (25 ~ 53% yield). Contrary to the above, pyrazine was the major product (22 ~ 49%) in the pyrolysis of the secondary and tertiary alkyl sulfones (R = i-C₃H₇, t-C₄H₉ and 1,2-dimethylpropyl) except for s-butyl one. An isomerization of the alkyl group in the 2-alkylpyrazine and the formation of alkene, alkane and 2-pyrazinesulfinic acid could not be found. The formation of 2-pyrazinol via successive intermediates of sulfinate and 2-alkoxypyrazine was not also observed.

■ Septentrionine and Septentriodine: Two New C₁₉-Diterpenoid Alkaloids from Aconitum septentrionale Koelle

S. William Pelletier,* Rajinder S. Sawhney, and Arne Jørgen Aasen

*Department of Chemistry, Institute for Natural Products Research, The University of Georgia, Chemistry Building, Athens, Georgia 30602-2556, U.S.A.

Abstract

Investigation of the alkaloids of Aconitum septentrionale has led to the isolation and structure elucidation of two new diterpenoid alkaloids, septentrionine (1) and septentriodine (2). These are the first reported examples of C₁₉-diterpenoid alkaloids bearing a carboxy ester group on the amide side chain. ¹³C nmr chemical shifts and assignments for these and related alkaloids are presented.

■ Cross-Coupling Reaction of 5-Substituted 4-Iodopyrimidines with Olefins in the Presence of Palladium Complex

Kiyoto Edo, Takao Sakamoto, and Hiroshi Yamanaka*

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

Abstract

On the olefinic coupling reaction of halopyrimidines, the presence of a 5-substituent was found to facilitate the coupling at the 4-position. Namely, 5-substituted (X=I, Br, Cl, C₂H₅O, C₂H₅) 4-iodo-2-isopropylpyrimidines (Ia-e) reacted with styrene to give the corresponding 4-styryl derivatives in 46, 46, 40, 87, and 51 % yields, respectively. The syntheses of the starting material, 4-iodopyrimidines (Ia-e) are also described.

■ Further Studies in the 6H-Pyrido[4,3-b]carbazole Area: The Chemistry of Some Dihydropyridine Intermediates

Michael Driver and Malcolm Sainsbury*

*School of Chemistry, University of Bath, Bath, Avon. BA2 7AY, U.K.

Abstract

The structure and reactions of dihydropyridine derivatives formed by the action of cyanide ion on certain pyridinium salts are discussed. For α-cyanodihydropyridines a ring-opening occurs.

■ On the Total Synhtesis of (±)-Flavipucine and Its Rearrangement to Isoflavipucine

John A. Findlay*

*Natural Products Research Center, Department of Chemistry, University of New Brunswick, Bag Service #45222, Fredericton, New Brunswick, E3b 5A3, Canada

Abstract

A clarification of imputed discrepancies in the literature relating to isoflavipucine is presented and the mechanism of epoxidation in the synthesis of flavipucine 1 is discussed in response to a claim of an unequivocally established elimination/addition pathway.

■ Octahydro-7(1H)-quinolones. VI. On the Interconversion of N-Substituted cis- and trans-Decahydroquinoline-2,5-diones

Takefumi Momose,* Shuji Uchida, Tatsuo Miyata, Kiyomi Ohshima, Kampoo Chiamchittrong, and Takeshi Imanishi

*Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama, Toyama 930-0194, Japan

Abstract

The equilibrium points for the isomerization of cis- and trans-decahydroquinoline-2,5-dione analogues (5 and 6) were investigated under basic and acidic conditions. The results can be explained by taking account of the equilibrium constant (K₂) for conformer 5’ (cis) ^→_← trans-isomer (6).

■ Reaction of 3-Aminopyrazole-4-carboxamides with Ethyl 3-Ethoxymethylene-2,4-dioxovalerate. Synthesis of 6-Acetyl-7-carbethoxypyrazolo[1,5-a]pyrimidine-3-carboxamide

Takushi Kurihara* and Yasuhiko Sakamoto

*Faculty of Pharmaceutical Science, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan

Abstract

Reaction of ethyl 3-ethoxymethylene-2,4-dioxovalerate (2) with the 3-aminopyrazole-4-carboxamides (1a,b) gave the corresponding aminomethylene derivatives (3a,b), which are cyclized to the pyrazolo[1,5-a]pyrimidine (6) and pyrrolo[1,2-a]pyrazolo[3,4-e]pyrimidine-1,5-dione (4), respectively. Some reactions of 6 are also described.

■ Synthesis of Thieno[3,4-b][1,4]diazepin-2-one

Yoshinori Tominaga, Hiroshi Fujito, Yoshiro Matsuda, and Goro Kobayashi*

*Faculty of Pharmaceutical Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan

Abstract

Thieno[3,4-b][1,4]diazepin-2-ones were prepared by condensation of 3,4-diaminothiophenes with 1,3-dicarbonyl compounds (ethyl acetoacetate, diethyl acetonedicarboxylate, diketene, ethyl benzoylacetate) in a good yield.

■ Studies on the Synthesis of Heterocyclic Compounds 775. Synthesis of β-Lactams by Acid Chloride- and Phosphate Anhydrideimine Methods

Tetsuji Kametani,* Shuichi Yokohama, Yuichi Shiratori, Sinko Aihara, Keiichiro Fukumoto, and Fumio Satoh

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

Abstract

Several 1,3,4-substituted 2-azetidinones (12 ~ 25) were synthesised by the acid chloride- and phosphate anhydride-imine methods.

■ Comments on a Recent Article Published in “Heterocycles” Entitled “Studies on the Synthesis of Bis-indole Alkaloids XIII. A Synthesis of Catharine” by J. P. Kutney et al

Pierre Potier*

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

■ Rebuttal to Comments Made by P. Potier Regarding Our Article in “Heterocycles” and Entitled “Studies on the Synthesis of Bis-indole Alkaloids. XIII. A Synthesis of Catharine.” by J. P. Kutney, J. Balsevich and B. R. Worth

James P. Kutney* and Brian R. Worth

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

■ Proton Magnetic Resonance Spectra of Phytoxanthones

M. Afzal and J. M. Al-Hassan*

*Biochemistry Department, Kuwait University, Safat 13060 P.O. Box 5969, Kuwait

Abstract

Proton magnetic resonance spectra of phytoxanthones with particular reference to structural elucidation has been discussed.