Regular Issue

Vol. 29, No. 2, 1989

32 data found. 1 - 30 listed Next Last
Communication | Regular issue | Vol 29, No. 2, 1989, pp.205-208
Published online:
DOI: 10.3987/COM-89-4506
Diterpenoid Alkaloids from Delphinium pictum Willd. The Structure of Pictumine

Gabriel de la Fuente,* Rafael Díaz Acosta, and Tomás Orribo

*Centro de Productos Naturales Orgánicos "Antonio González", Universidad de La Laguna, Avda. Astrofísico Franciso Sánchez, 2, 38206- La Laguna, Tenerife, Spain

Abstract

A new C-19 diterpenoid alkaloid pictumine (1) was isolated from Delphinium pictum Willd. subsp. pictum together with the known bases neoline (2), bullatine C (14-acetylneoline) (3), delphisine (8,14-diacetylneoline) (4), delphinine (5), chasmaconitine (6), and chasmanthinine (7). The structure of the new alkaloid was established by 1H and 13C-nmr spectra. The 13C-nmr data for alkaloids (3), (6), and (7) are also presented.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.209-212
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DOI: 10.3987/COM-89-4783
Cleavage Reactions of Penicillin Nuclei with Seyferth Reagents

Jahyo Kang,* Weon Bin Im, Soon-gyu Choi, Daesung Lim, Young Ro Choi, Hyung Geun Cho, and Jae Hyoung Lee

*Department of Chemistry, Sogang University, Mapoku, Seoul 121-742, Korea

Abstract

Various penams were converted to the corresponding 4-dihalomethylthio-azetidinones by PhHgCX3.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.213-216
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DOI: 10.3987/COM-89-4785
An Efficient Cyclosulfurization of N-(2-Hydroxyphenyl)thioamides with Superoxide. A Novel Route to Benzoxazoles

Yong Hae Kim,* Yong Il Kim, Hae Subg Chang, and Dae Chul Yoon

*Department of Chemistry, Korea Advanced Institute of Science and Technology, 373-1, Kusung-Dong, Yusung-Gu, Taejon, 305-701, Korea

Abstract

Treatment of N-(2-hydroxyphenyl)thioamides (1) with superoxide (02-/) at room temperature in dry acetonitrile resulted in the formation of 2-substituted benzoxazoles (7) in excellent yields.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.217-220
Published online:
DOI: 10.3987/COM-89-4789
The Reduction of 4-Acyk-β-lactams with Sodium Borohydride. A Possible Dichotomy of Stereochemical Pathways

Benito Alcaide, Gema Dominguez, and Joaquín Plumet*

*Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain

Abstract

Stereochemical result of the sodium borohydride reduction of 4-acyl-β-lactams to 4(α-hydroxyalkyl)-β-lactams is reported. The stereoselectivity is accounted for by competition between two possible stereochemical pathways,

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.221-224
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DOI: 10.3987/COM-89-4792
The Absolute Configuration of (+)-Canadaline

Miyoji Hanaoka,* Kazuyoshi Nagami, and Shingo Yasuda

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

Abstract

The absolute configuration of natural (+)-canadaline (1) was established to be S-configuration by its biomimetic synthesis from S-(-)-canadine (5).

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.225-230
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DOI: 10.3987/COM-89-4795
Falconericine and Falconeridine: Two New Alkaloids from Aconitum falconeri Stapf.

Haridutt K. Desai 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

Two new C19-diterpenoid alkaloids, falconericine (1) and falconeridine (2) have been isolated from the roots of Aconitom falconeri Stapf. and their structures deduced by spectroscopic methods and chemical correlation with alkaloids of established structures. A third alkaloid, falconeridinine (3) is likely an artefact of the isolation conditions. It has been synthesized by refluxing a solution of falconerine-8-acetate in ethanol.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.231-236
Published online:
DOI: 10.3987/COM-89-4798
Praziquantel Analogues. II. Synthesis of 4-Oxo-octahydropyrazino[1’,2’:1,2]pyrido[3,4-b]- and -[4,3-b]indoles

Nativitat Valls, Víctor M. Segarra, Xavier López, and Joan Bosch

*Laboratory of Organic Chemistry, Faculty of Pharmacy, University of Barcelona, Av. de Joan XXIII, s/n, 08028 Barcelona, Spain

Abstract

The title compounds 1a and 3 have been synthesized by cydization of the N-acyliminium ion generated from 1-(3-indolylethyl)piperazinedione 7 and by Pictet-Spengler condensation between isotryptamine and ester acetal 2a, respectively.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.237-242
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DOI: 10.3987/COM-89-4799
Addition of Indoles to N-Alkylpyridinium Salts. Synthesis of (Dihydropyridyl)indoles

Mercedes Alvarez, Rodolfo Lavilla, and Joan Bosch*

*Laboratory of Organic Chemistry, Faculty of Pharmacy, University of Barcelona, Av. de Joan XXIII, s/n, 08028 Barcelona, Spain

Abstract

The addition of the sodium salt of several indole derivatives 1 to N-alkylpyridinium salts 2 having an electron-withdrawing substituent at the β-position is studied.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.243-244
Published online:
DOI: 10.3987/COM-89-4810
A New Enantioselective Route to (+)-Quebrachamine

Morio Asaoka* and Hisashi Takei

*Department, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan

Abstract

Formal synthesis of (+)-quebrachamine was achieved using a new chiral building block 3-ethyl-5-trimethylsilyl-2-cyclohexenone.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.245-248
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DOI: 10.3987/COM-89-4814
Ring Transformation of 1,2,6-Thiadiazine 1,1-Dioxides into Pyrazoles. A Convenient Syntjesis of N-Alkylsulfamides

José Elguero, Pilar Goya, and Ana Martínez

*Instituto de Química Orgánica General, C. S. I. C., Calle Juan de Cierva, 3, 28006 Madrid, Spain

Abstract

Conversion of thiadiazines into pyrazoles by the action of hydrazine represents a new example of ring transformation and provides a new entry into N-methylsulfamide. The latter has been used to prepare an N-methyl-3,5-diaminothiadiazine which cannot be obtained by direct alkylatian.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.249-252
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DOI: 10.3987/COM-89-4815
Nucleophilic Cleavage of (2S,3S)-3-Phenylglycidol

Seiichi Takano,* Masashi Yanase, and Kunio Ogasawara

*Pharmaceutical Institute, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan

Abstract

Reaction of (2S,3S)-3-phenylglycidol with a variety of nucleophiles has been examined. The reaction occurred regioselectively at the benzylic center generally with an excellent diastereoselectivity. Although most of the nucleophiles yielded the products with inversion of the original chirality, trimethylaluminum furnished the retention product in a high diastereoselectlvity.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.253-256
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DOI: 10.3987/COM-89-4817
The Nucleophilic Reaction of Tricarbonyl(2-3-η-1H-azepine)iron. Novel Prepration and Thermal 1,5-Hydrogen Migration of 3-(1,3,5-Cycloheptatrien)-3H-azepine

Makoto Nitta,* Kazusato Shibata, and Hiroyuki Miyano

*Department of Chemistry, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan

Abstract

The nucleophilic reaction of tricarbonyl (2-5-η-1H-azepine) iron with tropylium cation and several electrophiles was studied. The decomplexation giving 3-(2,4,6-cycloheptatrienyl)-3H-azepine and its novel 1,5-hydrogen migration in the azepine ring are discussed.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.257-262
Published online:
DOI: 10.3987/COM-89-4825
The Di-π-methane Rearrangement in 3,4-Dibenzyl-2(5H)-furanone

Takefumi Momose,* Genzoh Tanabe, Hisayuki Tsujimori, Mié Higashiura, Ichiroh Imanishi, and Kenichi Kanai

*Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1, Kowakae, Higashi-Osaka 577-8502, Japan

Abstract

The photo-irradiation of 3,4-dibenzyl-2(5H)-furanone (5) in acetone or in methanol resulted in selective rearrangement of the 4-benzyl and gave 1-benzyl-5-phenyl-3-oxabicyclo[3.1.0]hexan-2-one (7) along with cis- and trans-3,4-dibenzyldihydro-2 (3H)-furanone (8a and 8b). Attempted rearrangement of the 3-benzyl system (13) resulted only in photo-reduction or photo-addition of solvent and gave no evidences for the di-π-methane rearrangement.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.263-268
Published online:
DOI: 10.3987/COM-89-4826
Reinvestigation of Cycloaddition of Nitrosobenzene towards 1,3-Diphenylisobenzofurans

Cheng-Tung Lin,* Li-Wei Din, and Sue-Lein Wang

*Department of Chemistry, Tunghai University, Taichung, Taiwan 40098, Taiwan, R.O.C.

Abstract

The title reaction gives rearrangement product of N-phenyl-α-phenyl-α-(o-benzoylphenyl)nitrones (8) rather than the earlier reported Diels-Alder cycloadduct 2. The molecular structure of 8a has been confirmed by a single crystal X-ray diffraction study.

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Communication | Regular issue | Vol 29, No. 2, 1989, pp.269-272
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DOI: 10.3987/COM-89-4832
Synthesis of Natural (S)-(—)-Tulipalin B Starting from L-Malic Acid as a Chiral Pool

Osamu Muraoka, Naoki Toyooka, Yumiko Ohshima, Norihiko Narita, and Takefumi Momose*

*Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1, Kowakae, Higashi-Osaka 577-8502, Japan

Abstract

The naturally occurring α-methylene-γ-lactone Tulipalin B (2) was synthesized enantioselectively starting from L-malic acid as a chiral pool in 15% overall yield.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.273-279
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DOI: 10.3987/COM-89-4479
Base-catalysed Condensation of 2,5-Dimethy-1-phenylpyrrole-3,4-dicarbaldehyde with β-Diketones

Jasna Vorkapic-Furac* and Mihela Suprina

*Faculty of Food Technology and Biotecnology, University of Zagreb, 41000 Zagreb, Croatia

Abstract

The base-catalysed condensation of 2,5-dimethyl-1-phenylpyrrole-3,4-dicarbaldehyde with 2,4-pentanedione and 1-(p-methoxyphenyl)-1,3-butanedion has been investigated under different reaction conditions (e.g. solvent, catalyst, temperature, time).

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.281-286
Published online:
DOI: 10.3987/COM-89-4664
Synthesis of Some β-(1-Benzimidazolyl)- and β-(1-Benzotriazolyl)-α-amino Acid Derivatives

Mojca Dobnikar, Marijan Kocevar, Slovenco Polanc, Miha Tisler, and Bojan Vercek*

*Department of Chemistry and Chemical Technology, E. Kardelj University, Murnikova 6, 61000 Ljubljana, Slovenia

Abstract

A convenient method for the preparation of methyl β-(1-benzimidazolyl)- and β-(1-benzotriazolyl)-α-benzoylaminoacrylates (5) from N-substituted o-phenylenediamine 2a is described. The synthesis of these two compounds proceeds either by ring opening of oxazolones 3 or by cyclization of acrylates 4.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.287-296
Published online:
DOI: 10.3987/COM-89-4703
[4+2]Cycloadducts of 5-Benzyloxy-2-pyridone with Electron Deficient Dienophiles. Regio- and Stereochemistry

Claus Herdeis* and Claudia Hartke

*Institut für Pharmazie und Lebensmittelchemie, Universität Wurzburg, Am Hubland, D-97074 Wurzburg, Germany

Abstract

The electron-rich 2-pyridone 4 is converted into the 2-azabicyclo [2.2.2] octane derivatives 8-12 via [4+2] cycloaddition. 10b is transformed to vinyl sulfone 6, an intermediate in a potential route to ibogamine 1. The regio- and stereochemistry of the cycloaddition reaction is reported.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.297-300
Published online:
DOI: 10.3987/COM-89-4710
Sigmatropic Rearrangement in Synthesis of C-8 Prenylated 3-(1’,1’-Dimethylallyl)coumarins: 3-(1’,1’-Dimethylallyl)seselin

Rosario Hernández Galán, Guillermo M. Massanet, Enrique Pando, Francisco Rodríguez Luis, and Javier Salvá

*Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Cádiz, Apartado 40, Puerto Real (Cádiz), Spain

Abstract

Synthesis of angular pyranocoumarin 3-(1’,1’-dimethylallyl)seselin, via sigmatropic rearrangement and prenylation of the romatic ring in good overall yiled is described.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.301-306
Published online:
DOI: 10.3987/COM-89-4714
17O Nmr Spectroscopy of Lactones

David W. Boykin,* David W. Sullins, and E. J. Eisenbraun

*Department of Chemistry, Georgia State University, University Plaza, Atlanta, GA 30303, U.S.A.

Abstract

Natural abundance 17O nmr spectroscopic data for 30 lactones acquired in acetonitrile at 75°C are reported: relationships beween 17O chemical shift and structure are discussed.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.307-312
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DOI: 10.3987/COM-89-4716
17O Nmr Spectroscopy of Lactams

David W. Boykin,* David W. Sullins, N. Pourahmady, and E. J. Eisenbraun

*Department of Chemistry, Georgia State University, University Plaza, Atlanta, GA 30303, U.S.A.

Abstract

Natural abundance 17O nmr spectroscopic data for 36 lactams acquired in acetonitrile at 75°C are reported: relationships between 17O chemical shift and structure are discussed.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.313-319
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DOI: 10.3987/COM-89-4725
Heterocyclic Spiro Compounds. III. Synthesis of [2R*,11bR*]-9.10-Dimethoxy-1,3,4,6,7,11b-hexahydrobenzo[a]quinolizine-2-spiro-3’-pyrrolidines and [2R*,11bR*]-9,10-Dimethoxy-1,3,4,6,7,11b-hexahydrobenzo[a]quinolizine-2-spiro-3’-pyrrolidin-2’-ones

J. Carlos Menéndez and Mónica M. Söllhuber*

*Departamento de Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad Complutense de Madrid, Ciudad Universitaria, 28040 Madrid, Spain

Abstract

The stereochemistry of succinimides 1, pyrrolidines 2 and pyrrolidinones 3 is reported on the basis of spectroscopic data. The results of the reduction of 1 with lithium aluminum hydride and diborane are described.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.321-337
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DOI: 10.3987/COM-89-400
Ab Initio Quantum-Chemical Study of the Influence of Mehtyl Substitution on the Redox Behaviour of 1,4-Dihydronicotinamides. Part 2: The Supermolecule Approach.

Jan D. Bossaerts, Frank C. Alderweireldt, and Paul Geerlings*

*Eenheid Algemene Chemie (ALGC), Fakulteit Wetenschappen, Vrije, Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium

Abstract

Ab initio minimal basis set quantum-chemical calculation on the interaction between methylated N-alkyl-1,4-dihydronicotinamides and the simplest keto derivative (formaldehyde) are reported. The supermolecule approach provides a distinctive improvement in the interpretation of the experimentally determined reactivity of the dihydronicotinamides in their reaction with keto compounds, as compared to previously used models (e.g. Krechl’s elongation model1,2) .

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.339-348
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DOI: 10.3987/COM-89-4748
Rearrangements of Arylhydrazones of N-Acylbenzimidazoles - Synthesis of 2-Aryl-1,2,4-triazolo[4,3-a]quinoxalinium Salts

Giuseppe Cusmano and Gabriella Macaluso

*Dipartimento Chimica Organica, Università digli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy

Abstract

The acid induced rearrangement of arylhydrazones of N-acylbenzimidazoles has been investigated. An initial 6π heteroelectrocyclic reaction involving the hydrazone side chain and the imidazole moiety, followed by a ring opening gave 4-(2-aminopheny1)-1,2,4-triazolium perchlorate 7 as intermediates. The latter species, depending on the substituent present in the triazole moiety, gave the 2-aryl-1,2,4-triazolo[4,3-a]quinoxalinium perchlorates 8 or 9 as the final rearranged products. Alkaline cleavage of the triazolo[4,3-a]quinoxalinium perchlorates 8 and 9 to 3-(arylformylhydrazino)guinoxaline derivatives 11 and 13 has been pointed out.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.349-354
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DOI: 10.3987/COM-89-4758
Reactivity of Isoselenazoles towards Nucleophilic Reagents

Francesco Lucchesini, Nevio Picci, Marco Pocci, Angela De Munno,* and Vincenzo Bertini

*Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgnimento 35, I-56126 Pisa, Italy

Abstract

Isoselenazoles have shown two reactive sites towards nucleophiles. LDA gives metallation in the 5-position exploited for synthetic purposes. Grignard reagents and LAH attack the selenium atom forming non-cyclic functionalized systems.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.355-357
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DOI: 10.3987/COM-89-4773
A New Neoflavanoid from Coutarea hexandra

Giuliano Delle Monache,* Bruno Botta, Vittorio Vinciguerra, and Eszter Gacs-Baitz

*Centro Chimica dei Recettori, C.N.R. , Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Roma, Italy

Abstract

A new neoflavone was isolated from Coutarea hexandra and assigned to 7,3’,4’-trihydroxy-5-methoxy-4-phenylcoumarin.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.359-363
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DOI: 10.3987/COM-89-4777
New Atypical Antidepressants: An Efficient Process for Preparing cis-1,3,4,6,7,11b-Hexahydro-2-methyl-7-aryl-2H-pyrazino[2,1-a]isoquinolines

Richard J. Schmiesing* and James R. Matz

*Department of Organic Chemistry, Pharmaceutical Division, Pennwalt Corporation, Rochester, New York 14623, U.S.A.

Abstract

Starting from 3-phenyl-2,piperazinone,cis-1,3,4,6,7,11b-hexahydro-2-methyl-7(4-chlorophenyl)2H-pyrazino[2,1-a] isoquinoline (1) was synthesized utilizing as the pivotal step of the sequence a highly stereocontrolled base-catalyzed equilbration bration of 3,4,6,7-tetrahydro-7(4-chlorophenyl)-2H-pyrazino[2,1-a]isoquinolin-1(11bH)-ones (2).

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.365-380
Published online:
DOI: 10.3987/COM-89-4782
Mild Synthesis of N-Alkyl- and N-Alkyl-β-carboline Anhydoro-bases Using Trifluoromethanesulfonates

Robert H. Dodd,* Guillaume Poissonnet, and 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

Abstract

Hindered 3-substituted pyrido[3,4-b]indoles (1-3) were quaternized in good yield using various alkyl trifluoromethanesulfonates generated in situ from the corresponding alcohol and trifluoromethanesulfonic anhydride in the presence of diisopropylethylamine in CH2Cl2. The resulting salts (4-13) were allowed to react with Cs2CO3 in refluxing DME to give the corresponding β-carboline anhydrobases (14-23). While attempts to N-acylate compounds (1-3) intermolecularly with different acylating agents failed, intramolecular acylation of the carboxylic acid derivative 24 using trifluoromethanesulfonic anhydride and diisopropylethylamine at - 78°C succeeded, to give the 1,4-benzodiazepine 28. The intermediacy of the mixed sulfonic-carboxylic anhydride in this acylation reaction was strongly supported by the novel, direct acylation of benzene with benzoic acid under the same conditions. Relevant spectroscopic data of these new compounds are discussed.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.381-390
Published online:
DOI: 10.3987/COM-89-4800
Formal Synthesis of the Indole Alkaloids Ngouniensine and Epingouniensine

M.-Lluïsa Bennasar, Ester Zulaica, Ramon Vila, and Joan Bosch*

*Laboratory of Organic Chemistry, Faculty of Pharmacy, University of Barcelona, Av. de Joan XXIII, s/n, 08028 Barcelona, Spain

Abstract

An alternative route to the tetracyclic ketones 9, key intermediates in our total synthesis of (±)-ngouniensine and (±)-epingouniensine, is reported.

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Paper | Regular issue | Vol 29, No. 2, 1989, pp.391-396
Published online:
DOI: 10.3987/COM-89-4807
Reaction of Bis(3,3-dimethyl-2-oxobutyl)sulfide with Lawesson’s Reagent. Formation of 1,4-Di-t-butyl-2,5,7-trithia[2.2.1]heptane and 2,5- and 2,6-Di-t-butyl-1,4-dithiins

Juzo Nakayama,* Keum Soo Choi, Shoji Yamaoka, and Masamatsu Hoshino

*Department of Chemistry, Faculty of Science, Saitama University, Saitama, Saitama 338-8570, Japan

Abstract

Treatment of bis(3,3-dimethyl-2-oxobutyl) sulfide (1) with Lawesson’s reagent (3 equiv.) in refluxing toluene for 2 h affords 1,4-di-t-butyl-2,5,7-trithia[2.2.1]heptane (2) in 42% yield and 2,5- and 2,6-di-t-butyl-1,4-dithiins (3 and 4) in 43% yields in the 1:4 ratio.

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32 data found. 1 - 30 listed Next Last