Regular Issue

Vol. 38, No. 8, 1994

30 data found. 1 - 30 listed
Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1707 - 1710
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DOI: 10.3987/COM-94-6745
Methylation of Tetrazathiapentalenes (10-S-3 Sulfurane) Fused with Pyridine and/or Pyrimidine Rings and Restricted Rotation of the Pyrimidine Ring: Chemical Evidences for N-S-N Hypervalent Bond

Katsuo Ohkata, Kazuhiro Yamamoto, Minoru Ohsugi, Mika Ohsawa, and Kin-ya Akiba*

*1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan, Faculty of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan


Methylation of the title compounds (10-S-3 sulfurane: 1-3) took place exclusively on the nitrogen at 3(4)-position and selectively on the nitrogen bound to the more electron-withdrawing heterocycle. The activation energy of the hindered rotation in 5 was lower for the pyrimidine ring (DGc = 20.2 kcal mol-1) bound to the methylated nitrogen than the other one (DGc = 22.9 kcal mol-1).

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1711 - 1715
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DOI: 10.3987/COM-94-6759
Application of Electro-Oxidative α-Cyanation of Aza-Rings to the Synthesis of Gephyrotoxin 223AB

Teng-Kuei Yang,* Shun-Tsai Yeh, and Yen-Yuan Lay

*Department of Chemistry, National Chung-Hsing University, Taichung, 400, Taiwan, R.O.C.


Six and five-membered cyclic α-cyanoamines have been prepared efficiently from N-benzylpiperidine and N-benzylpyrrolidine. These α-cyanoamines were successfully used in the synthesis of gephyrotoxin 223AB

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1717 - 1720
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DOI: 10.3987/COM-94-6777
A Synthesis of Pyrrolophenanthridone Alkaloids via Consecutive Directed Lithiation and Palladium-catalyzed Cross-coupling Reactions

Masatomo Iwao,* Hirokazu Takehara, Shigeru Obata, and Mitsuaki Watanabe

*Department of Chemistry, Faculty of Liberal Arts, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan


A short and convergent synthesis of pyrrolophenanthridone alkaloids, such as anhydrolycorin-7-one, oxoassoanine, hippadine, and pratosine, was developed by using directed lithiation and palladium-catalyzed corss-coupling as key reactions. Anhydrolycorin-7-one was converted to an antitumor alkaloid, kalbretorine, via directed lithiation and hydroxylation reactions.

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1721 - 1726
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DOI: 10.3987/COM-94-6778
Photochemistry of γ-Allenyl-substituted Conjugated Alkylidenecycloalkanones

Kunio Sugiyama,* Masato Yoshida, and Takashi Tsuno

*College of Industrial Technology, Nihon University, -2-1, Izumi-cho, Narashino, Chiba 275-8575, Japan


The photolyses of the γ-allenyl-substituted conjugated alkylidenecycloalkanones underwent the intramolecular oxa-Diels-Alder reaction and the E-Z geometrical isomerization, and for the cyclopentanone possessing a 3-methyl-1,2-butadienyl group, the intramolecular [2+2] cycloaddition also occurred. The oxa-Diels-Alder reaction takes place via photochemical process of the Z-enones.

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1727 - 1732
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DOI: 10.3987/COM-94-6779
Synthesis of 4,5-Disubstituted 1H-1,3,4,5-Tetrahydrobenz[cd]indole Derivatives

Géza Galambos,* Pál Csókási, Csaba Szántay, Jr., Gábor Czira, and Csaba Szántay*

*Central Research Institute for Chemistry, Hungarian Academy of Sciences, H-1025 Budapest, P.O.Box 17, Hungary


4,5-Disubstituted 1H-1,3,4,5-tetrahydrobenz[cd]indole derivatives are prepared through intramolecular Michael addition.

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1733 - 1736
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DOI: 10.3987/COM-94-6780
New Transformation of Lactam Sulfides to Tetrahydro-3,6-epithiobenzazocines via Bicyclic Sulfonium Salts with a Sulfonio Bridgehead

Tadashi Kataoka,*Yoshihide Nakamura, Harutoshi Matsumoto, Tetsuo Iwama, and Hiroshi Shimizu

*Gifu Pharmaceutical University, 6-1 Mitahora-higashi 5-chome, Gifu 502-8585, Japan


Benzothiazinone (1) was chlorinated with N-chlorosuccinimide and subsequently submitted to [2++4] cycloaddition with 1,3-dienes in the presence of silver perchlorate to afford cyclic sulfonium salts (3). Reactions of 3 with sodium borohydride or sodium hydride provided 4-vinyltetrahydro-3,6-epithiobenzazocine derivatives (9) in good yields.

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1737 - 1740
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DOI: 10.3987/COM-94-6782
Thiadiazolopyridinium Salts: Intermediates for Heterocyclic Synthesis

Ana Castro and Ana Martinez*

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


The high reactivity of [1,2,4]thiadiazolo[2,3-a]pyridinium salts against electrophiles is described. This fact provides a new and efficient synthetic route to several heterocycles such as thiazolines, thiadiazolines and thiadiazoline-3-ones carrying pyridylimino substituents.

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1741 - 1744
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DOI: 10.3987/COM-94-6783
Absolute Stereochemistry of the Pentacyclic Quaternary Indole Alkaloid Ophiorrhizine: Synthetic Incorporation of Cincholoipon Ethyl Ester into (-)-Ophiorrhizine

Masahi Ohba, Shigeki Seto, Tozo Fujii,* Melvyn V. Sargent, and Dayar Arbain

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


The absolute stereochemistry of the Ophiorrhiza alkaloid ophiorrhizine has been defined as shown in formula [(-)-1] by a chemical correlation with the Cinchona alkaloid cinchonine through cincholoipon ethyl ester [(+)-3] and the lactim ether [(+)-2]. The correlation was achieved by the chiral synthesis of ophiorrhizine [(-)-1] from (+)-2 via the intermediates [(+)-5], [(+)-7],[(+)-6], (8), [(-)-9], [(-)-10], (11), [(-)-12], and [(-)-13].

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1745 - 1746
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DOI: 10.3987/COM-94-6786
An Expedient Palladium-mediated Route to Methyl 3-Benzofuranylacetate

Kiyohiro Samizu and Kunio Ogasawara*

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


An expedient synthesis of methyl 3-benzofuranylacetate has been developed by employing the Heck reaction between 2-iodophenol and 2,5-dihydro-2,5-demethoxyfuran as a key step.

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1747 - 1750
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DOI: 10.3987/COM-94-6792
Enantioselective Synthesis of Pyrizinostatin, a Pyroglutamyl Peptidase Inhibitor

Masayuki Kitagawa and Kuniaki Tatsuta*

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


Enantiospecifically pure pyrizinostatin was synthesized from 2-methylfervenulone by using chiral imines of acetone.

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Communication | Regular issue | Vol 38, No. 8, 1994, pp. 1751 - 1756
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DOI: 10.3987/COM-94-6801
Diastereoselective Addition of Allyltriphenylstannane to 3-Sulfinylfurfural Mediated by Titanium(IV) Tetrachloride and Tin(IV) Tetrachloride

Yoshitsugu Arai* Tsutomu Masuda, Yukio Masaki, and Toru Koizumi

*Gifu Pharmaceutical University, 6-1 Mitahora-higashi 5-chome, Gifu 502-8585, Japan


The addition of allyltriphenylstannane to 3-sulfinylfurfural (3) in the presence of titanium(IV) tetrachloride proceeded with high diastereoselectivity to give the furyl alcohol (6), whereas the similar treatment with tin(IV) tetrachloride afforded the other diastereoisomeric alcohol (7), exclusively.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1757 - 1774
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DOI: 10.3987/COM-93-S161
Nuclear Magnetic Resonance Studies of Hyaluronan (HA): Evidence of Competitive Inhibition of Interchain Associations by Phospholipids which may result in decreased Anti-Inflammatory and Cartilage Protecting Properties of HA

Peter Ghosh,* Nongporn Hutadilok, and Aldo Lentini

*Raymond Purves Bone & Joint Research Laboratories, The Royal North Shore Hospital of Sydney, University of Sydney, St. Leonards, NSW 2065, Australia


The chain flexibility of solutions of hyaluronan (HA) of different molecular weights was determined by 1H-nmr spectroscopy in the absence and presence of the phospholipid Dipalmitoyl DL-α-phosphatidylchline (DPC). Sonication of high or low molecular weight HA with DPC for periods up to 60 min markedly increased HA chain flexibility as determined by observing the spin-spin relaxation times for the glucosamine acetyl group protons. From these data it is proposed that DPC competes for those hydrophobic centres along the HA chain which are normally responsible for the inter and intra chain interactions and which confer stiffiness to the HA molecule.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1775 - 1789
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DOI: 10.3987/COM-93-6645
Intramolecular Sulfenylation Using Sulfoxides. Preparation of 5H-Pyrrolo[1,2-a][3,1]benzothiazines

Joseph A. Picard, Shaowu Chen, and Dallas K. Bates*

*Department of Chemistry, College of Sciences and Arts, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan, 49931, U.S.A.


N-[2-(Phenylsulfinylmethyl)phenyl]pyrrole (4) undergoes transfer sulfenylation to N-(2-chloromethylphenyl)-2-phenylthiopyrrole (5‘) presumably via S-phneyl 5H-pyrrolo[1,2-a][3,1]benzothiazonium chloride (7). Depending upon the rigor of the reaction conditions, either N-(2-hydroxymethylphenyl)-2-phenylthiopyrrole (5) or its 5-trifluoroacetyl derivative (6) are obtained when 4 is treated with TFAA in trifluoroacetic acid. N-[2-(Methylsulfinylmethyl)aryl]pyrroles (12), when treated with gaseous hydrogen chloride and the resulting sulfonium salts refluxed in dichloroethane, produce substituted 5H-pyrrolo[1,2-a][3,1]benzothiazines (14). 1-Formyl-5H-pyrrolo[1,2-a][3,1]benzothiazines (22) are formed in one step in good yield when sulfoxides (12) are reacted with the Vilsmeier-Haack reagent (DMF/POCl3). No Pummerer rearrangement product is isolated from these reactions.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1791 - 1796
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DOI: 10.3987/COM-94-6693
Formylation of 2,5-Unsubsituted Oxazole: Preparation and Characterization of 2- and 5-Formyl-4-methyloxazoles

Marija Sindler-Kulyk,* Dragana Vojnovic, Nafis Defterdarovic, Zeljko Marinic, and Dunja Srzic

*Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 20, P.O Box 177, HR-10000 Zagreb, Croatia


Vilsmeier formylation of 4-methyloxazole (1) gave a mixture of 4-methyl-5-oxazolecarboxaldehyde (2) and 4-methyl-2-oxazolecarboxaldehyde (3) in 1:1 ratio. Both aldehydes were prepared unambiguously: aldehyde (2) by oxidation of 5-hydroxymethyl-4-methyloxazole (4) and reduction of chloride of 4-methyl-5-oxazolecarboxylic acid (5) and aldehyde (3) by n-butyllithium/DMF procedure. Aldehyde (2) sublimes in a refrigerator while aldehyde (3) forms hydrate, 5-dihydroxymethyl-4-methyloxazole (8).

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1797 - 1804
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DOI: 10.3987/COM-94-6696
Synthesis of Naphtho[2,3-b]pyranoquinones and Its Aza-Analogues from a Useful Benzopyranoquinone Intermediate

Ricardo Tapia,* Jaime A. Valderrama, and Carmina Quintanar

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


The synthesis of racemic pyranonaphthoquinone (2), a new cytotoxic agent, and its aza-analogues (11) and (12) employing Diels-Alder cycloaddition reactions is described.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1805 - 1811
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DOI: 10.3987/COM-94-6726
Inverse-Electron-Demand Diels-Alder Reactions of Condensed Pyridazines, 5. 1,4-Bis(trifluoromethyl)pyridazino[4,5-b]indole as an Azadiene

Norbert Haider* and Richard Wanko

*Institute of Pharmaceutical Chemistry, University of Vienna, Währinger Straße 10, A-1090 Vienna, Austria


The pyridazino[4,5-b]indole (3), which is conveniently available from 3-methylthioindole and the tetrazine (2), undergoes thermally induced inverse-electron-demand Diels-Alder reactions with enamines to afford the cycloalkene-annelated carbazoles (7,8) or the 2-substituted carbazole (9), respectively.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1813 - 1822
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DOI: 10.3987/COM-94-6747
A Novel and Convenient Route to (1H-1,2,4-Triazol-1-ylmethyl)phenols, Anilines, N-Alkylanilines and N,N-Dialkylanilines

Alan R. Katritzky,* Saad El-Zemity, and Hengyuan Lang

*Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, P. O. Box 117200, Gainesville, FL 32611-7200, U.S.A.


Phenols, naphthols, anilines, N-alkylanilines and N,N-dialkylanilines are readily alkylated by 1-hydroxymethyl-1,2,4-triazole to afford the corresponding triazole derivatives in good yields.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1823 - 1837
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DOI: 10.3987/COM-94-6750
Syntheses of Spiro(oxazolidinediones): Spiro[1H-isoindole-1,5‘-oxazolidine]-2‘,3(2H),4‘-triones and Spiro[1,2-benzisothiazole-3(2H),5‘-oxazolidine]-2‘,4‘-dione 1,1-Dioxides

Jay Wrobel* and Arlene Dietrich

*Wyeth-Ayerst Research Inc., CN 8000, Princeton, NJ 08543-8000, U.S.A.


Members of two novel families of spiro(oxazolidinediones) have been prepared. Spiro[1H-isoindole-1,5‘-oxazolidine]-2‘,3(2H),4‘-triones (4) were synthesized from the corresponding 1-hydroxy-1-carboxyethylisoindol-3-one (7) or (10) or their primary amide derivatives (14). In turn 7 and 10 were prepared from 2-bromobenzoic acid amides (6) and (9), or from N-alkylated isoquinolin-1,3,4(2H)-triones (12). Spiro[1,2-benzisothiazole-3(2H),5‘-oxazolidine]-2‘,4‘-dione 1,1-dioxides (5) were constructed from the appropriate 2,3-dihydro-3-hydroxy-1,2-benzisothiazole-3-carboxamide 1,1-dioxide (17). The immediate precursors to 14, ethyl esters (16) and (19), were prepared from benzenesulfonamide (15), or from 2-bromobenzenesulfonamide (18).

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1839 - 1844
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DOI: 10.3987/COM-94-6751
A New Entry to 5-Unsubstituted 3-Acyltetramic Acids from Aldehydes

Tetsuya Iida, Kozo Hori, Keiichi Nomura, and Eiichi Yoshii*

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


Reaction of aldehydes (prim-, sec-, and tert-) with diazoacetamide (8, 9) of N-substituted glycinate in the presence of Zr(IV) chloride in CH2Cl2 affords β-keto amides (11, 12) in good to high yields, which on treatment with n-Bu4NF in THF are led to N-protected 3-acyltetramic acids (13, 14).

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1845 - 1858
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DOI: 10.3987/COM-94-6753
Inverse-Electron-Demand Diels-Alder Reactions of Condensed Pyridazines, 4. Synthesis and Cycloaddition Reactions of 1,4-Bis(trifluoromethyl)pyrido[3,4-d]pyridazine

Nobert Haider,* Kurt Mereiter, and Richard Wanko

*Institute of Pharmaceutical Chemistry, University of Vienna, Währinger Straße 10, A-1090 Vienna, Austria


The title compound (8) was prepared by a [4+2] cycloaddition reaction of 3,6-bis(trifluoromethyl)-1,2,4,5-tetrazine (1) with a 4-piperidone-derived enamine and subsequent aromatization of the tetrahydro compound (7). The azadiene reactivity of 8 was investigated employing enamines and a ketene-N,S-acetal as electron-rich dienophiles. A series of new condensed isoquinolines (10, 11, 12a,b, 13) was obtained and one of them (13) was characterized by X-ray structure determination.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1859 - 1866
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DOI: 10.3987/COM-94-6755
Reactions of Monohalomethyl Aryl Ketoximes with Tetrasulfur Tetranitride: Much Improved Synthesis of 3-Aryl-1,2,5-thiadiazoles

Kyongtae Kim* and Jaeeock Cho

*Department of Chemistry, Seoul National University, San 56-1, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea


Reactions of chloromethyl aryl ketoximes (1, X = Cl) with tetrasulfur tetranitride in p-dioxane at reflux for 4 h afforded 3-aryl-1,2,5-thiadiazoles (2) in 37-92% yields, whereas those of bromo analogs under the same conditions gave 2 and 3-aryl-4-bromo-1,2,5-thiadiazoles (3) in 48-81% and 17-31% yields, respectively. However, the compounds (3) were not formed in the presence of pyridine. α-Nitrosostyrene and its ring-substituted derivatives (4) are proposed as intermediates for the formations of 2.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1867 - 1880
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DOI: 10.3987/COM-94-6756
New Heterocyclic Ring Systems: The Syntheses of 2H,3H,7H-Imidazo[1‘,2‘:1,2]pyrido[4,3-b]indoles and 2H,3H,4H,8H-Pyrimido[1‘,2‘:1,2]pyrido[4,3-b]indoles

Kazuho Harada,* Hitoshi Someya, and Shonosuke Zen

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


Heterocyclic [1,2]-annulated pyrido[4,3-b]indoles (9 and 10) were synthesized in five step sequences starting from 4-hydrazino-1H-pyrid-2-one.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1881 - 1887
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DOI: 10.3987/COM-94-6757
Synthesis of 3-Substituted Pyrazolo[1,5-a]pyridines by Electrophilic Reactions

Yasuyoshi Miki,* Sanae Yagi, Hiroko Hachiken, and Masazumi Ikeda

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


Reactions of pyrazolo[1,5-a]pyridines with Eschenmoser‘s salt, activated alkenes and alkynes, and chlorosulfonyl isocyanate provided general routes to 3-substituted pyrazolo[1,5-a]pyridines such as 3-dimethylaminomethyl- and 3-(2-nitroethyl)pyrazolo[1,5-a]pyridines, 1-phenyl-3-(pyrazolo[1,5-a]pyrid-3-yl)-2-propen-1-ones, 4-(pyrazolo[1,5-a]pyrid-3-yl)-3-buten-2-one, pyrazolo[1,5-a]pyridine-3-carboxamide, and pyrazolo[1,5-a]pyridine-3-carbonitrile.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1889 - 1896
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DOI: 10.3987/COM-94-6758
EPC-Synthesis of (S)-3-Hydroxy-3-mercaptomethylquinuclidine, a Chiral Building Block for the Synthesis of the Muscarinic Agonist AF 102B

Michael Bös* and Rolf Canesso

*Pharma Division, Pharma Preclinical Research & Development, F.Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland


The catalytic modification of the Sharpless-epoxidation reaction was employed in a short EPC-synthesis of the title compound. The asymmetric epoxidation of the allylic alcohol (6) proceeded in 75 % yield and 94 % enantiomeric excess. In a 4 step sequence the epoxide (7) was transformed to (S)-3-hydroxy-3-mercaptomethylquinuclidine (11).

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1897 - 1908
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DOI: 10.3987/COM-94-6765
Bullatin and Bullanin: Two Novel, Highly Cytotoxic Acetogenins from Asimina triloba

Geng-xian Zhao, Jocelyn H. Ng, John F. Kozlowzki, David L. Smith, and Jerry L. McLaughlin*

*Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmacal Sciences, Purdue University, 1333 Robert E. Heine Pharmacy Building West Lafayette IN 47907, Indiana 47907, U.S.A.


Two new highly cytotoxic adjacent bis-tetrahydrofuran acetogenins, bullatin (2) (10-hydroxy-4-deoxybullatacin) and bullanin (5) (30-hydroxy-4-deoxybullatacin), have been isolated from the ethanolic extract of the stem bark of Asimina triloba by directing the fractionation with brine shrimp lethality. In addition to these two new compounds, two previously reported acetogenins, squamocin (3) (28-hydroxy-4-deoxybullatacin) and motrilin (4) (29-hydroxy-4-deoxybullatacin) which are new to this species, were obtained. Through spectral analysis these four acetogenins were structurally identified as hydroxylation isomers of bullatacin (1) which was recently patented as an antitumor agent. All of these acetogenins showed high potencies in the brine shrimp test (BST) and in cytotoxicity tests against human solid tumor cell lines in culture, with certain potencies quite comparable to those of bullatacin (1) and several orders of magnitude greater than those of adriamycin.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1909 - 1918
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DOI: 10.3987/COM-94-6767
Unexpected Results in the Reduction of Tetracyclic Enamides. Structure, Stereochemistry and Conformation of a 20β-Hydroperoxyimine

Denise Dugat,* Gérard Dauphin, and Jean-Claude Gramain

*URA 485 CNRS, Chimie des Substances Naturelles, Université Blaise Pascal (Clermont-Ferrand II), 63177 Aubiere Cedex, France


Reduction of Nb-allyl-20-ethyltetracyclic enamide (7) with lithium aluminium hydride afforded the expected enamine (12) and 4a-oxoethylhexahydrocarbazolones (18a,b). Reduction of Nb-unsubstituted enamide (6), under the same conditions, gave imine (9), enamine (11) and a 20β-hydroperoxytetracyclic imine (19) resulting from the peroxydation of 9 and 11. The C-20 stereochemistry of 19 was established by means of 2D 1H nmr and NOE difference spectroscopy.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1919 - 1926
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DOI: 10.3987/COM-94-6771
Synthesis of 4-Hydroxy- and 4-Alkoxyquinolinequinones Using Oxidative Demethylation with Cerium(IV) Ammonium Nitrate

Yashiyasu Kitahara, Takanobu Yonezawa, and Akinori Kubo*

*Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan


4-Hydroxy-5,8-quinolinediones (11), 4-hydroxy-5,6-quinolinedione (12), 4-alkoxy-5,8-quinolinediones (14, 15), 4-alkoxy-5,6-quinolinediones (16a, 17a), and 4-alkoxy-7,8-quinolinediones (16b, 17b) were synthesized by oxidative demethylation of the corresponding 4(1H)-quinolinones (6) and 4-alkoxyquinolines (9, 10) with cerium (IV) ammonium nitrate.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1927 - 1932
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DOI: 10.3987/COM-94-6773
Garcipyran, a Novel 6-Aryl-1,2-benzopyran Derivative from Garcinia kola

Masatake Niwa,* Junko Ito, Kenji Terashima, and Muhd Aqil

*Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tenpaku, Nagoya 468-8503, Japan


A novel 6-aryl-1,2-benzopyran derivative named garcipyran was isolated from the roots of Garcinia kola (Guttiferae) and the structure was elucidated by spectroscopic and chemical methods. The plausible biogenetic pathways of 6-aryl-1,2-benzopyran (garcipyran) and 5-arylbenzofuran (garcifuran-B) were also discussed.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1933 - 1936
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DOI: 10.3987/COM-94-6776
A New Sesquiterpene Lactone Glucoside of Ixeris chinensis

Shwu-Woan Lee, Zong-Tsi Chen, and Chiu-Ming Chen*

*Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 30013, Taiwan, R.O.C.


A new sesquiterpene lactone glucoside, 8-epicrepioside G(1) together with two known compounds, 8-epidesacylcynaropicrin glucoisde (2) and ixerin D (3) were isolated from the whole plant of Ixeris chinensis. Their structures were determined on the basis of chemical and spectroscopic evidence. Compounds 1, 2 and 3 taste of strong bitterness.

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Paper | Regular issue | Vol 38, No. 8, 1994, pp. 1937 - 1942
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DOI: 10.3987/COM-94-6789
Three New Acridone-Coumarin Dimers from a Citrus Plant

Yuko Takemura, Motoharu Ju-ichi,* Mitsuo Omura, Mitsumasa Haruna, Chihiro Ito, and Hiroshi Furukawa

*Faculty of Pharmaceutical Science, Mukogawa-Women‘s University, 11-68 Koushien Kyuban-Cho, Nishinomiya, Hyogo 663-8179, Japan


Three new acridone-coumarin dimers, named dioxinoacrimarine-A (1), neoacrimarine-E (2) and acrimarine-N (3) were isolated from the roots of Citrus plant and their structures were elucidated on the basis of spectroscopic methods.

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30 data found. 1 - 30 listed