HETEROCYCLES

■ Tscheschamine — A New Cyclopeptide Alkaloid from the Bark of Zizyphus sativa Gaertn

Arif Hussain Shah,* Vidya Bhushan Pandey, Gert Eckhardt, and Ghulam Abbas Miana

*Research Centre, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh-11451, Saudi Arabia

Abstract

A new minor 13-membered cyclopeptide alkaloid tscheschamine has been isolated from the bark of Zizyphus sativa and its structure was determined on the basis of spectral studies and hydrolysis.

■ New Cularine-Related Alkaloids from Sarcocapnos baetica Subsp. integrifpolia

Luis Castedo,* Susana López, and Carmen Villaverde

*Departamento de Química Orgánica, Sección de Alcaloides del C.S.I.C, Facultad de Química, Universidad de Santiago, 15706 Santiago de Compostela, Spain

Abstract

We report the isolation of four new cularine-related alkaloids from Sacocapnos baetica (Boiss.& Reuter) Nyman subsp. integrifolia (Boiss) Cuatrec.: (+)-4-hydroxysarcocapnidine (1), 3,4-dioxosarcocapnidine(2), (+)-sarcocapnidine N-oxide (3) and (+)-N-methylcularine (4).

■ An Efficient Synthesis of (±)-3-Demethoxyerythratidinone

Hiroyuki Ishibashi,* Tatsunori Sato, Masako Takahashi, Mayumi Hayashi, and Masazumi Ikeda

*Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan

Abstract

(±)-3-Demethoxyerythratidinone (10), an alkaloid of Erythrina lithosperma, was synthesized in nine steps and 37% overall yield from homoveratrylamine and cyclohexane-1,4-dione monoethylene acetal.

■ A New Synthesis of 5-Aza[2.2.3]cyclazines by [8+2]Cycloaddition of 3-Imino-3H-pyrrolizines with Dimehtyl Acetylenedicarboxylete

Yoshinori Tominaga,* Yoshiki Matsuoka, and Akira Hosomi*

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

Abstract

Reaction of 3-imino-3H-pyrrolizines, generated in situ, with dimethyl acetylenedicarboxylate (DMAD) in the presence of palladium on charcoal in toluene gave 5-aza-[2.2.3]cyclazine derivatives in good yields.

■ Pictet-Spengler Reactions in Aprotic Media. N_b-Benzyl Promoted Retention of Optical Activity in the Synthesis of an Indole Substituted Azabicyclo[3.3.1]nonane, a Key Template for the Synthesis of Macroline Alkaloids

Lin-hua Zhang and James M. Cook*

*Department of Chemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, U.S.A.

Abstract

The N_b-benzyl group (see 7) has been employed in the Pictet-Spengler reaction in refluxing benzene to provide complete retention of optical activity in this process. The tetrahydro-β-carbolines 3b (trans) and 4b (cis) were independently converted into the indolo substituted azabicyclo[3.3.1]nonane 1b and its antipode 1c, respectively. Consideration of the thermodynamic and kinetic parameters involved in both the Pictet-Spengler and Dieckmann condensations has now permitted the stereospecific synthesis of tetracyclic ketone 2 in high yield and in optically active form.

■ Synthesis of Racemic Carbapenems with a 6β-Methyl Group

Hisao Satoh* and Teruji Tsuji

*Shionogi Research Laboratories, Shionogi & Co. Ltd., Fukushima-ku, Osaka 553-0002, Japan

Abstract

The first total synthesis of some cnrbapenem antibiotics having amethyl group at the 6β position of the carbapenem nucleus is described.

■ Synthesis and Carbon-13 Magnetic Spectra of Pyridinium Salts Derived from Nucleosides and Nucleobases

Zofia Gdaniec, Slawomir Mielewczyk, Ryszard W. Adamiak,* and Bohdan Skalski

*Institute of Bioorganic Chemistry, Polish Acadeamy of Sciences, 61-704 Poznan, Noskowskiego 12/14, Poland

Abstract

Synthesis of N-[9-(β-D-ribofuranosyl)purin-6-yl]pyridinium chloride 9 and N-(9-(β-D-ribofuranosyl)-2-aminopurin-6-yl]pyridinium chloride 10 is described. Carbon-13 nmr spectra of those and other nucleoside- and nucleobase-derived pyridinium salts are presented.

■ Preparation of D-Penicillamine. Reaction of Penilloic Acid, Penicilloic Acid α-Amides and Benzylpenicillin with N,N‘-Diphenylethylenediamine

Toshihisa Ogawa,* Kazuyuki Tomisawa, and Kaoru Sota

*Research Center, Taisho Pharmaceutical Co., Ltd., 1-403 Yoshino-Cho, Saitama-city, Saitama 330-8530, Japan

Abstract

Reaction of benzylpenilloic acid (1) with N,N’-diphenylethylenediamine (2) in mixture of water, acetic acid and toluene under reflux yielded D-penicillamine (4). In a similar way, 4 was also obtained from benzyl- and phenoxymethylpenicilloic acid α-amides (6a-f) and benzylpenicillin potassium salt (13). The structures of the byproducts formed in these reactions were also determined.

■ Regioselectivity in the 1,3-Dipolar Cycloaddition Reaction of 3-Methyloxazolium 5-Olates with Acetylenic Dipolarophiles

Piero Dalla Croce and Concetta La Rosa*

*Dipartimento di Chimica Organica e Industriale, Centro C. N. R., Università degli Studi di Milano, V. Venezian 21, I-20133 Milano, Italy

Abstract

The cycloaddition reaction of unsymmetrically substituted munchnones with monosubstituted alkynes has been examined. The reaction affords a mixture of regioisomeric pyrroles. The observed regioselectivity is qualitatively discussed on the basis of the MO-perturbation theory.

■ New Alkaloids from Pancratium maritimum L

M. Pilar Vázquez Tato, Luis Castedo, and Ricardo Riguera*

*Departamento de Química Orgánica, Sección de Alcaloides del C.S.I.C, Facultad de Química, Universidad de Santiago, 15706 Santiago de Compostela, Spain

Abstract

Two new alkaioids, 6-O-methylhaemanthidine (1) and O,N-dimethylnorbelladine (2), were isolated from Pancratium maritimum L., together with lycorine, hippeastrine, galanthamine, haemanthamine, haemanthidine, vittatine. 11-hydroxyvittatine, hordenine and 9-O-demethylhomolycorine (all previously isolated from this plant), and habranthine, ungiminorine and ungiminorine N-oxide.

■ An Approach to the Enantioselective Synthesis of 2-Azabicyclo[2.2.1]hept-5-en-3-one

Olga Caamaño, Ana Eirín, Franco Fernández,* Generosa Gómez, and Eugenio Uriarte

*Departamento de Química Orgánica , Facultad de Farmacia, Universidad de Santiago de Compostela, E-15706, Santiago de Compostela, Spain

Abstract

2-Azabicyclo[2.2.1]hept-5-en-3-one (1) was obtained with a 13% enantiomeric excess by hydrolysis of the adduct formed by Diels-Alder addition of cyclopentadiene to the new chiral dienophile (+)-10-camphorsulphonyl cyanide (6) which was prepared in three steps from (+)-10-camphorsulphonic acid (3) in 44% overall yield.

■ A Short, Stereocontrolled Synthesis of (—)-Detoxinine

William R. Ewing and Madeleine M. Joullié*

*Department of Chemistry, University of Pennsylvania, 231 South 34th Street Philadelphia, PA 19104-6323, U.S.A.

Abstract

An improved synthesis of (-)-detoxinine is described.

■ Tirucaline — A New Macrocyclic Diterpene from Euphorbia tirucalli

Abdul Qasin Khan, Tahir Rasheed, and Abdul Malik*

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

Abstract

A new macrocyclic diterpene, tirucslicine has been isolated from the fresh and undried latex of Euphorbia tirucslli. Its structure has been assigned as (1) an the basis of chemicnl and spectral studies.

■ A One Step Synthesis of 4-Cyanopyrazoles

Hamdi M. Hassaneen,* Hamed A. Ead, Nehal M. Elwan, and Ahmed S. Shawail

*Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt

Abstract

Reaction of nitrilimines 2 with fumaronitrile 6 yielded 4-cyanopyrazoles 8 in good yields. The structures of 8 were substantiated by comparison with their regioisomers 5-cyanopyrazoles 5, prepared by addition of 2 to acrylonitrile followed by oxidation of the 2-pyrazoline cycloadducts 4.

■ New Secoiridoids from Isertia haenkeana

Angel Rumbero-Sánchez and Purificación Vázquez

*Depatramento de Química, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain

Abstract

Eight new secoiridoid glycosides (7R)- and (7S)-haenkeanoside (8) and (9), (7R)- and (7S)-isohaenkeanoside (10) and (11), (7R)- and (7S)-O-methylhaenkeanoside (12) and (13), and (7R)-and (7S)-O-methylisohaenkeanoside (14) and (15), were isolated from leaves of Isertia haenkeana, and their structures have been established on the basis of spectral data and chemical transformations. These compounds are the first report of any coumaroyl secoiridoid morroniside type with a trans- and cis- configuration at acyl double bond. Moreover, compounds 12, 13, 14, and 15 exhibit a methoxy group (C-7) in the aglycone part.

■ Pulsed Positive/Negative Chemical Ionization Mass Spectrometry of Pyrazines

Anna Arnoldi,* Olga Baldi, and Albert Griffini

*Dipartimento di Scienze Molecolari Agroalimentari, Università digli Studi di Milano, via Celoria 2, 20133 Milano, Italy

Abstract

The mass spectrometric behavior of thirteen pyrazines under PPINICI conditions was investigated using methane as reagent gas. Differences in the mass spectra were observed depending on analyte concentration. Structural informations can be obtained, but data are hignly influenced by experimental conditions.

■ Synthesis of 2-(4-Piperidylmethyl)indoles. Intermediates for the Synthesis of Strychnos Alkaloids

Josep Bonjoch,* Josefina Quirante, Ana Linares, and Joan Bosch*

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

Abstract

The synthesis of 2-[(cis-1-benzyl-3-ethyl-4-piperidyl)-methyl]indole (6) by three alternative procedures is reported, the condensation of the organodilithium derivative of N-trimethylsilyl-o-toluidine with ethyl cis-1-benzyl-3-ethyl-4-piperidineacetate (1) being the most efficient method. The indole derivative 6 has been converted into azocinoindole 7 by oxidative cyclization with mercuric acetate and into piperidylmethylindole 8 by debenzylation. Compounds 7 and 8 are known intermediates in previous syntheses of the Strychnos indole alkaloids tubifolidine and tubifoline.

■ Synthesis and Structure of a Fluorescent, Tricyclic Analogue of 2’-Deoxyadenosine and of a Prodrug by N-Annelation of 2’-Deoxyguanosine and 9-[(2-Hydroxyethoxy)methyl]guanine (Acyclovir), Respectively

Shiv Kumar, Fred T. Oakes, Scott R. Wilson, and Nelson J. Leonard*

*Roger Adams Laboratory, School of Chemical Sciences, University of Illinois, 1209 West California Street, Urbana, IL 61801-3731, U.S.A.

Abstract

Chemical modification of 2’-deoxyguanosine and of 9-[(2-hydroxyethoxy)-methyl]guanine, respectively, into a fluorescent, tricyclic analogue of deoxyadenosine with potential for use as a probe for enzymatic reactions, and into a prodrug of an effective antiherpetic, acyclovir, is described. The X-ray structure determination of 8-amino-3,10-dihydro-10-oxo-3-(β-D-2-deoxyribofuranosyl)-3H-1,3,5-triazino[1,2-a] purine (dIdA’-metamorphosine) revealed that the nucleoside is in syn conformation, x = 55.1°, with an intramolecular hydrogen bond 0(5’)-H(5’)---N(4)= 2.810Å. The 2’-deoxyribofuranosyl ring is in a 2’-endo envelope (²E) conformation, and the conformation about the C(4’)-C(5’) bond is gauche-gauche.

■ Commemoration for 65th Birthday, December 19, 1988

Arnold Brossi*

*Section of Medical Chemistry, Laboratory of Analytical Chemistry, NIDDK, National Institute of Health, Bethesda, MD 20982, U.S.A.

■ Research on Bioactive Natural Products at the NIH (1976-1988)

Arnold Brossi

*Section of Medical Chemistry, Laboratory of Analytical Chemistry, NIDDK, National Institute of Health, Bethesda, MD 20982, U.S.A.