Regular Issue

Vol. 43, No. 4, 1996

19 data found. 1 - 19 listed
Communication | Regular issue | Vol 43, No. 4, 1996, pp. 731 - 735
Published online:
DOI: 10.3987/COM-95-7309
Cascade SRN1 Reactions in 5-Nitroimidazole Series

Patrice Vanelle,* Kamel Benakli, José Maldonado, Christine Roubaud, and Michel P. Crozet

*Laboratoire de Chimie Organique, Faculté de Pharmacie, 27 Bd J. Moulin, 13385 Marseille Cedex 05, France


The reaction of 3-chloro-2-chloromethyl-1-(1-methyl-5-nitroimidazol-2-yl)prop-1-ene with 2-nitropropane anion which gives three products is shown to proceed by an initial SRN1 mechanism followed by another SRN1 leading to the bis-C-alkylation product or SN2 or SN2’ and Michael reactions.

PDF (129KB)
Communication | Regular issue | Vol 43, No. 4, 1996, pp. 737 - 743
Published online:
DOI: 10.3987/COM-95-7338
Synthesis of Benzimidazo[2,1-a]isoquinolines and 5,6-Dihydrobenzimidazo[2,1-a]isoquinolines

Qun Sun and Edmond J. LaVoie *

*Department of Pharmaceutical Chemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08855, U.S.A.


The formation of substituted benzimidazo[2,1-a]isoquinolines by the palladium-catalyzed intramolecular cyclization of 2-[2-(2-trimethylsilyl-ethynyl)phenyl]-1H-benzimidazole is described. 5,6-Dihydrobenzimidazo[2,1-a]isoquinolines were formed directly during the condensation of a 1,2-phenylenediamine with an o-vinylbenzaldehyde. These synthetic routes represent useful approaches for the preparation of pharmacologically-active benzimidazo[2,1-a]isoquinolines.

PDF (135KB)
Communication | Regular issue | Vol 43, No. 4, 1996, pp. 745 - 749
Published online:
DOI: 10.3987/COM-95-7341
An Efficient Synthesis of Reduced Flavones via Diels-Alder Addition to 4H-Pyran-4-ones

Paul W. Groundwater, David E. Hibbs, Michael B. Hursthouse, and Miklós Nyerges*

*Department of Chemistry, Unvierity of Wales Cardiff, P. O. Box 912, Cardiff CF1 3TB, U. K.


The 4H-pyran-4-one (4c) undergoes Diels-Alder cycloaddition with electron-rich dienes to give the reduced flavones (7), whereas the pyran-4-one (4b) and 2-phenyl-4H-pyran-4-one (4a) are unreactive. The 3D structure of the adduct 7a of 4c with Danishefsky’s diene (6a) was confirmed by X-ray crystallography.

PDF (117KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 751 - 754
Published online:
DOI: 10.3987/COM-95-7266
Synthesis of Silylated Naphthopyrans and Naphthodipyrans

Mohammad Reza Saidi,* Reza Zadmard, and Tahereh Saberi

*Department of Chemistry, Sharif University of Technology, P.O. Box 11356-9516, Tehran, Islamic Republic of Iran


Thermal Claisen rearrangement-cyclization of naphthyl trimethylsilylpropargyl ethers afforded silylated naphthopyrans and naphthodipyrans in good to moderate yields.

PDF (102KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 755 - 766
Published online:
DOI: 10.3987/COM-95-7293
Enantioselective Total Synthesis of Irniine and Bgugaine, Bioactive 2-Alkylpyrrolidine Alkaloids

Akino Jossang,* Ahmed Melhaoui, and Bernard Bodo

*Laboratoire de Chimie des Substances Naturelles, Muséum National d'Histoire Naturelle, URA 401 CNRS, 63 rue Buffon 75005 Paris, France


An asymmetric total synthesis of the 2-(R)-alkylpyrrolidines, (-)-irniine (1a) and (-)-bgugaine (1b), toxic and antibiotic component of the tubers of Arisarum vulgare, and (+)-(S)-irniine (1c), was carried out by condensation of the corresponding 4-oxoalkanoic acid (9) with chiral phenylglycinol. Acids (9) were prepared from a hetero-organocuprate (I) complex, generated by reaction of methylcopper (I) with alkylmagnesium bromides and methyl chlorocarbonylpropionate. Alkaloids (1a, 1b and 1c) displayed anti Gram(+) bacterial (MIC 12.5 - 50 μg/ml) and antifungal (MIC 6.25 - 50 μg/ml) activities.

PDF (373KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 767 - 774
Published online:
DOI: 10.3987/COM-95-7307
Regioselective Synthesis of Thiopyrano[2,3-b][1]benzopyran-5(2H)-ones

Krishna C. Majumdar* and Gour H. Jana

*Department of Chemistry, University of Kalyani, Kalyani-741 235, W. B., India


A number of thiopyrano[2,3-b][1]benzopyran-5(2H)-ones (5a-g) have been regioselectively synthesised in 65-82% yields from 4-propynyloxycoumarins (8a-g) through thionation followed by sigmatropic rearrangement.

PDF (181KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 775 - 780
Published online:
DOI: 10.3987/COM-95-7324
Synthesis of 4-Substituted Methyl 3-(2,3-Epoxy)propoxythiophene-2-carboxylates

Jaime Lissavetzky* and Ignacio Manzanares

*Instituto de Química Médica (C. S. I. C.), Juan de Cierva, 3, E-28006 Madrid, Spain


The synthesis of 4-substituted methyl 3-hydroxythiophene-2-carboxylates is reported. The selective O-alkylation by two methods of these compounds gives the correspondent epoxy derivatives.

PDF (198KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 781 - 786
Published online:
DOI: 10.3987/COM-95-7325
Three New Purinium Derivatives, Heteromines A, B, and C from Heterostemma brownii

Yun-Lian Lin, Hae-Pyng Lee, Jun-Chih Ou, and Yueh-Hsiung Kuo

*Department of Chemistry, National Taiwan University, Taipei, Taiwan, R.O.C.


From the aerial parts of Heterostemma brownii Hay., three new purinium derivatives, heteromines A, B, and C were isolated. Their structures were elucidated as 6-methoxy-7,9-dimethyl-2-dimethylaminopurinium chloride, 6-methoxy-7,9-dimethyl-2-methylaminopurinium chloride, and 2-amino-6-methoxy-7,9-dimethylpurinium chloride on the basis of spectroscopic and chemical methods.

PDF (140KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 787 - 798
Published online:
DOI: 10.3987/COM-95-7328
Novel Tocopherol Compounds IV. 5-Tocopherylacetic Acid and Its Derivatives

Thomas Rosenau, Wolf Dieter Habicher, and Chen-Loung Chen*

*Department of Wood and Paper Science, North Carolina State Univesity, Raleigh, NC 27607-8005, U.S.A.


A new class of tocopherol (vitamin E) compounds, 5-tocopherylacetic acid derivatives, is presented. The synthesis and some unexpected properties of these compounds, such as relatively high thermal and chemical stability, are described and discussed in comparison with the labile 5a-halogeno-, 5a-alkoxy- or 5a-amino-substituted tocopherols.

PDF (374KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 799 - 807
Published online:
DOI: 10.3987/COM-95-7330
N-Formyl- and N-Hydroxyaporphine Alkaloids from Formosan Hernandia nymphaeifolia

Ih-Sheng Chen,* Jih-Jung Chen, and Ian-Lih Tsai

*Graduate Institute of Pharmaceutical Sciences, Kaohsiung Medical College, Kaohsiung, Taiwan, R.O.C.


Three new aporphine alkaloids, (+)-N-formylovigerine (1), (+)-N-formylhernangerine (2), (+)-N-hydroxyovigerine (3) and one known aporphine alkaloid, (+)-N-formylnornantenine (4), have been isolated from the trunk bark of Hernandia nymphaeifolia.

PDF (203KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 809 - 816
Published online:
DOI: 10.3987/COM-95-7362
Transformations of Some 3-Benzamido-2,5-dioxo-5,6,7,8-tetrahydro-2H-1-benzopyrans with Nucleophiles

Polonca Trebse, Slovenko Polanc, Marijan Kočevar*, and Tomaz Solmajer

*Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, 61000 Ljubljana, Slovenia


Transformation of 3-benzamido-2,5-dioxo-5,6,7,8-tetrahydro-2H-1-benzopyrans (1-3) to the corresponding quinolin-2(1H)-ones (4-18) with nitrogen-containing nucleophiles (amines and hydrazines) under various conditions is described. In order to clarify the observed results, heats of formation of possible product pairs were calculated.

PDF (224KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 817 - 828
Published online:
DOI: 10.3987/COM-95-7366
Metallation of Methoxy-2(1H)-quinolinones

Trinidad Moreno, María Fernández, Elena de la Cuesta, and Carmen Avendaño*

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


Methoxy group at 5- or 6-position of 2(1H)-quinolinones is compatible with the regioselective electrophilic substitution and chain enlargement at the 3-position imposed by the ortho-directed effect of the quinolinone lithium salt. The coordination effect of a methoxy group at the 8-position changes the reaction course, precluding the ortho-directed metallation and enhancing the conjugate addition at the 4-position.

PDF (335KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 829 - 838
Published online:
DOI: 10.3987/COM-95-7372
New Procedures for the Synthesis and Analysis of 5,10,15,20-Tetrakis(sulphophenyl)porphyrins and Derivatives through Chlorosulphonation

Antonio M. d'A. Rocha Gonsalves *, Robert A. W. Johnstone *, Mariette M. Pereira, Alexandra M. P. de SantAna, Arménio C. Serra, Abílio J. F. N. Sobral, and Paul A. Stocks

*Department of Chemistry, University of Liverpool, Liverpool L69 3BX, U.K.


Tetrakisarylporphyrins are conveniently chlorosulphonated in high yields. These chlorosulphonyl compounds may be converted in high yield into sulphonic acid derivatives through reaction with a variety of nucleophiles so as to give, for example, the free sulphonic acid, a sulphonamide or a sulphonate ester.

PDF (299KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 839 - 849
Published online:
DOI: 10.3987/COM-95-7374
Synthesis of 1,3,5-Triazine Derivatives by the Reaction of S,S'-Dimethyl N-Cyanocarbonimidodithioate with Amides

Shinya Kohra *, Kazuo Ueda, and Yoshinori Tominaga

*Faculty of Liberal Arts, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852, Japan


S,S’-Dimethyl N-cyanocarbonimidodithioate (1) reacted with amides (2) in the presence of sodium hydride in a mixture of benzene and N,N-dimethylacetamide to give the corresponding N-acyl-N’-carbamoyl-S-methylisothioureas (3). Refluxing of 3 in methanol gave the corresponding cyclized product, 1,3,5-triazin-2(1H)-one derivatives (4). Compounds (4) were found to be useful intermediates for the synthesis of trisubstituted 1,3,5-triazines.

PDF (283KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 851 - 859
Published online:
DOI: 10.3987/COM-95-7375
Acetal Formation by Metal Ion-mediated Desulfurization-Condensation of Thioketones with Diols and Phenols

Isao Shibuya *, Eisaku Katoh, Yasuo Gama, Akihiro Oishi, Yoichi Taguchi, and Tohru Tsuchiya

*National Institute of Materials and Chemical Research, 1-1 Higashi, Tsukuba, Ibaraki 305, Japan


The acetal formation of thioketones with several diols and phenols through metal ion-mediated desulfurization-condensation was investigated. The reactivities of 4,4’-bis(dimethylamino)thiobenzophenone, "thio-Michler’s ketone" (TMK) and xanthene-9-thione (XT) toward α,ω-alkanediols [HO(CH2)nOH, n= 2 ~ 4] in the presence of silver trifluoroacetate and triethylamine were compared. The reaction of TMK with glycerol, trans- and cis-1,2-cyclohexanediols, α,α’-dihydroxy-o-xylene and biphenyl-2,2-diol in the presence of silver salt gave the corresponding acetals in good yields. On the other hand, copper(I) chloride, in place of silver(I) salt, was useful for catechol and pyrogallol to give their acetals, respectively. It was thus found that thioketones are new and versatile acetalizing reagents for diols and phenols.

PDF (218KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 861 - 871
Published online:
DOI: 10.3987/COM-95-7377
Preparation and Interconversion of Phenylselenenylated and Alkylselenenylated Aromatic Compounds

Lars Engman * and Per Eriksson

*Uppsala University, Institute of Chemistry, Department of Organic Chemistry, Box 531, S-751 21 Uppsala, Sweden


Phenylselenenyl and alkylselenenyl sulfates were found to efficiently and mildly introduce one or several phenylselenenyl or alkylselenenyl group into activated aromatic or heteroaromatic compounds. When treated with methylselenenyl sulfate, veratrole and 2,2’,3,3’-tetramethoxybiphenyl afforded 2,3,7,8-tetramethoxyselenanthrene and 2,3,7,8-tetramethoxydibenzoselenophene, respectively, via oxidative demethylation at selenium/cyclization. Phenylseleneylated thiophenes were selectively hydrodeselenenated at the 2- and/or 5-positions by treatment with the appropriate amount of n-butyllithium at -78 °C followed by hydrolysis.

PDF (257KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 873 - 882
Published online:
DOI: 10.3987/COM-95-7380
2-Alkyl- and 2-Cyano-substituted 1-Acyl-3,4-epoxy-1,2,3,4-tetrahydroquinolines — Reactions with O-Nucleophiles

Romana Hiessböck and Martin Kratzel*

*Institut für Pharmazeutische Chemie der Universität Wien, Pharmaziezentrum, Althanstrasse 14, A-1090 Wien, Austria


The oxirane ring openint of 1,2,3,4-tetrahydroquinoline 3,4-epoxides with O-nucleophiles is described leading to 3,4-diol derivatives (5 - 7) with well defined stereochemistry. As by-products nitrate esters are formed. The reaction was applied to produce the epimeric epoxide (10) via a four step synthesis.

PDF (270KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 883 - 889
Published online:
DOI: 10.3987/COM-96-7392
N-Hydroxyamide-containing Heterocycles. Part 7. Preparation and Photochemical Behavior of 1-Benzyloxy-2(1H)-pyrazinones

Junko Ohkanda, Toshihiko Kumasaka, Aki Takasu, Tadashi Hasegawa, and Akira Katoh*

*Department of Industrial Chemistry, Faculty of Engineering, Seikei University, Musashino, Tokyo 180, Japan


Synthesis of 1-benzyloxy-2(1H)-pyrazinones having substituents at C-5 and C-6 positions and their photochemical behavior have been studied. Upon irradiation 1-benzyloxy-2(1H)-pyrazinones underwent N-O bond cleavage in high quantum yields. The rearrangement of the benzyloxy group to C-3 position of the ring and [2+2] cycloaddition were also observed.

PDF (173KB)
Paper | Regular issue | Vol 43, No. 4, 1996, pp. 891 - 898
Published online:
DOI: 10.3987/COM-96-7396
Convenient Synthesis of Fragment E of Antibiotic, Nosiheptide

Chung-gi Shin *, Yasuhiro Yamada, Keiichiro Hayashi, Yasuchika Yonezawa, Kazuyuki Umemura, Tsuyoshi Tanji, and Juji Yoshimura

*Laboratory of Organic Chemistry, Faculty of Technology, Kanagawa University, Rokkakubashi, Kanagawa-ku, Yokohama 221, Japan


A convenient synthesis of Fragment E, 4-hydroxymethyl-3-methylindole-2-carboxylic acid (1), from 2-methyl-3-nitrobenzyl alcohol through six steps conversion in 32% overall yield is described.

PDF (239KB)
19 data found. 1 - 19 listed