HETEROCYCLES

■ A Novel Synthesis of 6-Methoxy and 7-Methoxy Flavonols

Takkellapati Sudhakar Rao, Shubhada Deshpande, Hari Har Mathur, and Girish Kumar Trivedi*

*Department of Chemistry, Indian Institute of Technology, Powai, Bombay 400 076, India

Abstract

Condensation of 4-methoxy- (1) or 5-methoxy- (2) salicylaldehyde with ω-nitrostyrene (3-6) in the presence of triethylamine yields 7-methoxy or 6-methoxy-3-nitro-2H-flavene (7-13), which on treatment with alkaline hydrogen peroxide yields the corresponding flavonol (7a-13a) .

■ A New Vapor-phase Synthesis of Thiazoles

Joseph S. Amato,* Sandor Karady, Brian T. Phillips, and Leonard M. Weinstock

*Merck Sharp and Dohme Research Laboratories, Rahway, NJ 07065, U.S.A.

Abstract

The vapor-phase reaction of imines with sulfur dioxide to produce thiazoles has been studied at 450-500°C. Of the imines investigated acetone methyl imine was the most studied which produced 4-methylthiazole in 70% yield.

■ Synthesis of 2,2-Dimethyl-2H-chromenes

Manuel J. Cortés,* Gabriel R. Haddad, and Jaime A. Valderrama

*Facultad de Química, Pontificia Universidad Católica de Chile, Casilla 306, Correo 22, Santiago, Chile

Abstract

The antijuvenile hormones precocenes I and II (1,2), and related 2,2-dimethyl-2H-chromenes (12,13) were synthesized by oxidative cyclization of o-isoprenylphenols with m-chloroperbenzoic acid, followed by dehydration of the corresponding 3-chromanols with methyltriphenoxyphosphonium iodide.

■ A Novel Ring-opening Reaction of Aziridine Induced by the Formation of Nitrogen-substituted Carbanion of Nonstabilized Type

Otohiko Tsuge,* Shuji Kanemasa, Hiroyuki Suga, and Koyo Matsuda

*Graduate School of Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan

Abstract

Desilylation of 1-(trimethylsilylmethyl)aziridines causes a novel ring-opening reaction of aziridine. Only aziridines whose ring bears at least one anion-stabilizing moiety undergo the desilylation, and the resultant carbanion of nonstabilized type changes into a stabilized one inviting the ring-opening. The types of products depend upon the number of anion-stabilizing moieties as well as the quenching reagents employed.

■ Synthesis of Novel 5-Alkoxycarbonyl-5,6-dihydropyrimidin-4(3H)-ones from 3-Substituted 2-Alkoxycarbonyl-2-propenoates and Amidines

Hidetsura Cho,* Masaru Ueda, Yoshiko Ohnaka, and Mariko Hayashimatsu

*Suntory Institute for Biochemical Research, Suntory Co. Ltd., 1-1-1, Wakayamadai, Shimamotocho, Mishimagun, Osaka 618-0024, Japan

Abstract

A cyclization of 3-substituted 2-alkoxycarbonyl-2-propenoates with acetamidine, benzamidine, guanidine, or 1,1-dimethylguanidine hydrochloride in the presence of 1-2 eq of metal alkoxide afforded novel 5-alkoxycarbonyl-5,6-dihydropyrimidin-4(3H)-ones in good yield (R¹=Me, Et, ⁱPr; R²=phenyl, furyl, thienyl, pyridyl, alkyl; R³=Me, C₆H₅, NH₂, NMe₂). Substitution of a functional group on the phenyl ring influenced the trans-cis relationship between the 5-proton and the 6-proton of the dihydropyrimidone skeleton, namely the ratio of trans/cis increased from ortho substitution (3/2-2/1) and meta (9/1) to para (only trans).

■ Alancine, a New Benzoquinolizidine Alkaloid from Alangium lamarckii

Sunil K. Chattopadhyay, David J. Slatkin, Paul L. Schiff, Jr.,* and Anil B. Ray

*Department of Pharmacognosy, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, U.S.A.

Abstract

The new benzoquinolizidine alkaloid alancine (1) has been isolated from the stem bark of Alangium lamarckii Thw. (Alangiaceae) and characterized by spectral evidence and preparation from ankorine (2).

■ Ring Transformation of 1-Azadibenzo[c,f]bicyclo[3.3.1]nona-3,6-dienes: Novel Routes to Dibenzopyrrolizidine and Dibenzotropane

Takashi Nomoto and Hiroaki Takayama*

*Faculty of Pharmaceutical Sciences, Teikyo University, 1091-1 Suarashi, Sagamiko-machi, Tsukui-gun, Kanagawa 199-0195, Japan

Abstract

Base-induced reactions of N-methyl quaternary salts of 11b-methyl-7,11b-dihydro-5H-isoindolo[2,3-b]isoindole (4), which were effectively transformed from readily available 1-azadibenzo[c,f]bicyclo[3.3.1]nona-3,6-dienes (1), were examined and consequently, 5,12-dimethyl-5,10-imino-10,11-dihydro-5H-dibenzo[a,d]cycloheptens (6) and 6,10b-dimethyl-5,6,6a,10b-tetrahydrobenzo[3,4]cyclobut[l,2-c]isoquinolines (7) were obtained via Stevens rearrangement.

■ Synthesis of Alkaloids, (±)-Sceletium Alkaloid A₄ and (±)-N-Acetyltortuosamine

Junko Koyama,* Teruyo Sugita, Kiyoshi Tagahara, Yukio Suzuta, and Hiroshi Irie

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

Abstract

Synthesis of alkaloids, (±)-Sceletium alkaloid A₄ and (±)-N-acetyltortuosamine, was accomplished by application of a new method for constructing cycloalkenopyridines by thermal rearrangement of oxime O-allyl ethers.

■ The Synthesis of C-13 Labeled Vitamin E, [2a-¹³C]all-rac-α-Tocopherol

Shiro Urano* and Mitsuyoshi Matsuo

*Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-, Japan

Abstract

Vitamin E with a ¹³C-labeled isoprenoid side chain, [2a-¹³C]all-rac-α-tocopherol (1), was synthesized by condensation of trimethylhydroquinone with a mixture of [3a-¹³C]phytol (9a) and its geometrical isomer (9b). The ¹³C-labeled phytol was prepared using 5,9,13-trimethyltetradecan-1-al (6) as an intermediate and [¹³C]methyl iodide as a ¹³C source. The total yield of the labeled α-tocopherol was 65.4% on the basis of [¹³C]methyl iodide.

■ A Convenient Synthesis of [1,2]Diazepinones by the Reaction of Hydrazines on 5-Acetyl Pyran-2,6-dione and 2-Pyrones

Suhas R. Pendnekar, Shrinivas D. Samant, and Kodand D. Deodhar*

*Department of Chemistry, Indian Institute of Technology, Powai, Bombay 400 076, India

Abstract

Reactions of hydrazine and phenyl hydrazine with 5-acetylpyran-2,6-dione (5) yielded [1,2]diazepinones 8 and 12, respectively. The formation of 12 was via the acid carboxamide 10. The diazepinone 8 was also obtained from 2-pyrones 13 and 14 with hydrazine, while the latter also afforded pyrazolodiazepinone 15. Both 13 and 14 on treatment with phenylhydrazine furnished N-phenyldiazepinone 9.

■ Formation of Aminoquinazolinones from N-(2-Aminobenzoyl)-N’-aroylhydrazines

Melinda Gál,* Endre Tihanyi, and Péter Dvortsák

*Institute for Drug Research Ltd., H-1325 Budapest, POB 82, Hungary

Abstract

The ring closure of N-(2-aminobenzoyl)-N’-aroylhydrazines 3 in AcOH/TsOH yielded 2-aryl-3-amino-4(3H)-quinazolinones 6 instead of 2-aryl-3,4-dihydro-5H-1,3,4-benzotriazepin-5-ones 4 as reported before. The structure of the aminoquinazolinones 6 was confirmed by unambiguous synthesis.

■ On the Ring Cleavage of Isoxazoles: A Note

Juan Antonio Ciller, Carlos Seoane, and José Luis Soto*

*Departamento de Química Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain

Abstract

A new heterocyclic compound is obtained from the basic cleavage of an isoxazole ring in the presence of an aldehyde.

■ Synthesis of Some Neodihydrothebaine and Bractazonine Isomers

Hubert G. Theuns,* Herman B. M. Lenting, Cornelis A. Salemink, Hitoshi Tanaka, Masayoshi Shibata, Kazuo Ito, and Robert J. J. Ch. Lousberg

*Laboratory of Organic Chemistry, Agricultural University, De Dreijen 5, 6703 BC Wageningen, The Netherlands

Abstract

The synthesis of four isomeric dibenz[d,f]azonine compounds is described. Neither of these substances may be confused with the natural Papaver bracteatum alkaloids neodihydrothebaine and bractazonine.

■ Total Synthesis of Neodihydrothebaine and Bractazonine, Two Dibenz[d,f]azonine Alkaloids from Papaver bracteatum

Hubert G. Theuns,* Herman B. M. Lenting, Cornelis A. Salemink, Hitoshi Tanaka, Masayoshi Shibata, Kazuo Ito, and Robert J. J. Ch. Lousberg

*Laboratory of Organic Chemistry, Agricultural University, De Dreijen 5, 6703 BC Wageningen, The Netherlands

Abstract

The total syntheses of neodihydrothebaine and bractazonine, two dibenz[d,f]azonine alkaloids from Papaver bracteatum, are described. Neodihydrothebaine is prepared in a total synthesis for the first time. A new and efficient total synthesis of bractazonine is presented.

■ Conversion of Pyrimidines into Amidinopyrazole by Action of Aminoguanidine Hydrochloride

Gabriel Meinchi, Jaouad Naciri, Bruno Kokel, and Michel Hubert-Habart*

*Section de Physique et Chimie, Institut Curie, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France

Abstract

Aminoguanidine hydrochloride reacts with pyrimidines of type 1 giving the unexpected 1-amidino-3-methyl-4-pyrazolyl methyl ketone amidinohydrazone dihydrochloride 2.

■ Reaction of Methyl Tetronate with 3,4-Dihydro-6,7-dimethoxy-2-methylisoquinolinium Iodide

Robert J. Rafka, Walter A. Szarek,* and David B. MacLean

*Department of Chemistry, Queen’s University, Kingston, Ontario K6L 3N6, Canada

Abstract

The lithium salt of methyl tetronate adds to 3,4-dihydro-6,7-dimethoxy-2-methylisoquinolinium iodide and affords a mixture of three coupled products. Zinc chloride has been found to suppress formation of one of these isomers. These compounds may be thought of as precursors to a new class of C-nucleosides.

■ The Isolation and Structure of Strictimine, a New Piperidine Alkaloid from the Roots of Rhazya stricta

Atta-ur-Rahman* and Khurshid Zaman

*H. E. J. Postgraduate Institute of Chemistry, University of Karachi, Karachi-75270, Pakistan

Abstract

A new bispiperidine alkaloid, “strictimine”, has been isolated from the roots of Rhazya stricta to which structure (1) has been assigned on the basis of spectroscopic studies.

■ High Valent Chromium Heterocyclic Complexes-II: New Selective and Mild Oxidants

Harry B. Davis, Roger M. Sheets, William W. Paudler, and Gary L. Gard*

*Department of Chemistry, Portland State University, Portland, Oregon 97207, U.S.A.

Abstract

The new mild oxidizing agents, pyrazinium-N-oxide chlorochromate (PzOCC), tripyridinium hydrochloride chlorochromate (TPCC), and naphthyridinium dichromate (NapDC) have been prepared and characterized. A study of the oxidative behavior of these new compounds relative to pyridinium chlorochromate (PCC) and bipyridinium chlorochromate (BPCC) with selected primary and secondary alcohols is reported.

■ Deltatsine, a New C₁₉-Diterpenoid Alkaloid from Delphinium tatsienense Franch

Balawant S. Joshi, Jan A. Glinski, Hitesh P. Chokshi, Szu-ying Chen, Santosh K. Srivastava, and S. William Pelletier*

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

Abstract

The isolation and structure elucidation of a novel alkaloid deltatsina (2A) from the roots of Delphinium tatsienense Franch is described. The Structure was established on the basis of spectroscopic data and a chemical correlation with delcosine (11).

■ A Convenient Method for the Preparation of 3-Acetyl-1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]quinolizin-2-one, a Key Intermediate for the Synthesis of Ajmalicine

Bhim C. Maiti and Satyesh C. Pakrashi*

*Indian Institute of Chemical Biology, Calcutta-700 032, India

Abstract

Reaction of 3,4-dihydro-β-carboline (1) and 3,4-dihydroisoquinoline (7a-b) with ethoxymethyleneacetylacetone (2a) and ethyl ethoxymethyleneacetoacetate (2b) yielded new tetra- and tricyclic compounds (4a-b, 8a-d). The enaminone 4a on NaBH₄ reduction led to the title compound.

■ Synthesis and Characterization of 2,9,16,23-Tetra(3-pyridyloxy)phthalocyanine in the Form of Its Zinc(II) Chelate

Stuart W. Oliver and Thomas D. Smith*

*Chemistry Department, Monash University, Clayton, Victoria, 3168, Australia

Abstract

2,9,16,23-Tetra(3-pyridyloxy)phthalocyanine has been prepared by the reaction of lithium chloride with 5-(pyridyloxy)-1,3-diiminoisoindoline in 2-(dimethylamino)ethanol solution followed by demetallation. The zinc chelate of the phthalocyanine has been prepared in a similar condensation reaction using zinc chloride.

■ Absorption, Circular Dichroism and Magnetic Circular Dichroism Studies on 2-Thiouracils

Akio Tajiri,* Nobuko Yamamoto, Masahiro Hatano, and Tohru Ueda

*Chemical Research Institute of Non-Aqueous Solutions, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan

Abstract

The longest wavelength absorption band of 2-thiouracil in solution has been clarified to be superposition of two π→ π* electronic transitions taking place in a thioketone form of the three possible tautomers of 2-thiouracil.

■ A CNDO Study on the n → π^* Contribution to MCD in Aza Analogues of Anthracene

Akio Tajiri* and Johannes Winkler

*Chemical Research Institute of Non-Aqueous Solutions, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan

Abstract

Magnetic circular dichroism of aza analogues of anthracene was interpreted on the basis of the CNDO/S method. Magnetic coupling of the lowest n → π* state with the lowest π → π* state was suggested to be of appreciable importance in acridine, phenazine and benz[a]acridine.

■ Organic Conductors: Synthesis and Complex Formation of Substituted 2,2’-(2,6-Naphthalene)bis[1,3-dithiolium] Salts

Shuh-Chung Chen and Eugene LeGoff*

*Department of Chemistry, Michigan State University, East Lansing, MI 48824, U.S.A.

Abstract

The synthesis and reactions the bis(dithiolium) salts 7 and 8 are described. Conversion to iodine and TCNQ complexes were investigated.

■ Isolation of (—)-Stepholidine, an Alkaloid of Antiserotonergic-like Activity from Sinomenium acutum

Kazuo Ichikawa, Takeshi Kinoshita, Akiko Itai, Yoichi Iitaka, and Ushio Sankawa*

*Faculty of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

Abstract

A tetrahydroprotoberberine alkaloid, (-)-stepholidine (5), was isolated as an active principle showing antiserotonergic-like activity from Sinomenium acutum Rehder et Wilson (Menispermaceae) which has been used as an oriental medicinal drug (Japanese name, Bohi; Chinese name, Fang-Ji) in Japan. An aporphine type alkaloid, liriodenine (4), was isolated first time from this plant along with known alkaloids hitherto obtained from this plant.

■ Reactivity of Cycloimmonium Ylides

Gheorghe Surpateanu* and Alain Lablache-Combier

*Laboratoire de Chimie Organique, Faculté de Technologie Chimiqui, Institut Polytechnique de Iasi, Splai Bahlui Stg .71, 6600 Iasi, Romania