Regular Issue

Vol. 75, No. 6, 2008

18 data found. 1 - 18 listed
Review | Regular issue | Vol 75, No. 6, 2008, pp. 1305 - 1320
Published online: 1st February, 2008
DOI: 10.3987/REV-07-627
Palladium-Mediated Intramolecular Biaryl Coupling Reaction for Natural Product Synthesis

Hitoshi Abe* and Takashi Harayama*

*Faculty of Pharmaceutical Science, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan


An intramoleculer biaryl coupling reaction is a useful technique for the synthesis of certain types of heterocyclic compounds. This short review describes recent advances in the Pd-mediated intramolecular C-C bond formation reaction between two aromatic rings, and several examples of natural product synthesis using this reaction. The mechanistic aspect of this reaction is also explained.

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Communication | Regular issue | Vol 75, No. 6, 2008, pp. 1321 - 1328
Published online: 22nd February, 2008
DOI: 10.3987/COM-08-11340
A Convenient Synthesis of 5-Amino-Substituted 1,2,4-Oxadiazole Derivatives via Reactions of Amidoximes with Carbodiimides

Maria Ispikoudi, Konstantinos E. Litinas, and Konstantina C. Fylaktakidou*

*Molecular Biology and Genetics Department, Democritus University of Thrace, 68100 Alexandroupolis, Greece


5-Amino substituted 1,2,4-oxadiazole derivatives were easily prepared, in one step and in high yields, via reactions of a variety of aryl, benzyl, cycloalkyl and alkyl amidoximes with commercially available carbodiimides. Alkyl carbodiimides reacted with amidoximes in toluene to give 5-alkylamino-1,2,4-oxadiazoles, whereas aromatic carbodiimide reacted in DMF to give initially the intermediate O-amidoxime adducts, which were further cyclized to the corresponding 5-arylamino-1,2,4-oxadiazoles.

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Paper | Regular issue | Vol 75, No. 6, 2008, pp. 1329 - 1354
Published online: 26th February, 2008
DOI: 10.3987/COM-07-11276
Synthesis of the Diazatricyclic Core of Madangamines via Cyclic N,O-Acetalization-Bridgehead Reduction

Yuta Yoshimura, Takahiko Kusanagi, Chihiro Kibayashi, Naoki Yamazaki,* and Sakae Aoyagi*

*School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan


A new approach to synthesize the diazatricyclic core of the madangamine alkaloids is described. The synthesis involves intramolecular N,O-acetalization of the keto-aminophenol which enables rapid construction of the 2-azabicyclo[3.3.1]nonane skeleton. Reductive C-O bond cleavage of the N,O-acetal has been accomplished by using AlH3 as the source of nucleophilic hydrogen as well as the Lewis acid character. This strategy also demonstrates the utility of such approach in the stereoselective construction of the central 2,6-diazatricyclo[,9]dodecane core with a quaternary carbon center at C-4 found in the madangamine alkaloids.

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Paper | Regular issue | Vol 75, No. 6, 2008, pp. 1355 - 1370
Published online: 15th February, 2008
DOI: 10.3987/COM-07-11303
Synthesis of 8-Hydroxyimidazo[1,2-a]pyridine-2-carboxylic Acid and Its Derivatives

Uros Groselj, Jure Bezensek, Anton Meden, Jurij Svete,* Branko Stanovnik,* Marko Oblak, Petra Stefanic Anderluh, and Uros Urleb

*Department of Organic Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, P.O. Box 537, 1000 Ljubljana, Slovenia


Two new imidazo[1,2-a]pyridines, 8-hydroxyimidazo[1,2-a]pyridine-2-carboxylic acid (4) and ethyl 8-hydroxyimidazo[1,2-a]pyridine-2-carboxylate (6) were prepared via cyclization of 2-aminopyridin-3-ol (1) with bromopyruvic acid (2) and ethyl bromopyruvate (3), respectively. 8-Hydroxyimidazo[1,2-a]pyridine-2-carboxylic acid (4) was successfully coupled with various amino acid derivatives via its active ester intermediate into the corresponding amides 22-27. O-protected ethyl 8-hydroxyimidazo[1,2-a]pyridine-2-carboxylate 11 was transformed into its hydrazide 13, acyl azide 14, and amide 15 derivatives.

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Paper | Regular issue | Vol 75, No. 6, 2008, pp. 1371 - 1383
Published online: 15th February, 2008
DOI: 10.3987/COM-07-11307
Studies with Malononitrile Derivatives: Synthesis and Reactivity of 4-Benzylpyrazole-3,5-diamine, 4-Benzylisoxazole-3,5-diamine and Thiazolidin-3-phenylpropanenitrile

Saleh Mohammed Al-Mousawi,* Moustafa Sherief Moustafa, and Mohamed Hilmy Elnagdi

*Department of Chemistry, Faculty of Science, University of Kuwait: P.O. Box 5969, Safat: 13060 Kuwait


Benzylmalononitrile 6 reacts with hydrazines, and hydroxylamine hydrochloride to yield the 4-benzylpyrazole-3,5-diamines 7 and 4-benzylisoxazole-3,5-diamine 9, respectively. Pyrazole-3,5-diamines 7 could be readily reacted with α,β-unsaturated nitriles to yield pyrazolo[1,5-a]pyrimidines 20. Benzylmalononitrile, also reacted with thioglycolic acid to yield tautomeric mixture of 2-(4-hydroxythiazol-2-yl)-3-phenylpropanenitrile 29 and 2-(4-oxothiazolidin-2-yl)-3-phenylpropanenitrile 30 that coupled with benzene diazonium chloride to yield 2-(4-oxo-5-(phenylhydrazono)-thiazolidin-2-ylidene)-3-phenylpropanenitrile 31.

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Paper | Regular issue | Vol 75, No. 6, 2008, pp. 1385 - 1396
Published online: 26th February, 2008
DOI: 10.3987/COM-07-11313
A Facile Synthesis of Cycloether Systems Bearing [2,4]-Oxazole Units

Marcelo Incerti, Carolina Fontana, Laura Scarone, Guillermo Moyna, and Eduardo Manta*

*Cátedra de Química Farmacéutica, Departamento de Química Orgánica, Facultad de Química, Universidad de la República, Avenida General Flores 2124, Montevideo 11800, Uruguay


We present a concise and high-yielding route for the preparation of novel five-, six-, and seven-membered cycloether systems bearing [2,4]-oxazoles units. The approach is based on intramolecular electrophilic oxirane ring expansion strategies and β-hydroxyamide cyclodehydration-oxidation reactions mediated by Deoxo-Fluor and BrCCl3/DBU.

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Paper | Regular issue | Vol 75, No. 6, 2008, pp. 1397 - 1405
Published online: 12th February, 2008
DOI: 10.3987/COM-07-11315
Salaprionol and Ponkoranol with Thiosugar Sulfonium Sulfate Structure from Salacia prinoides and α-Glucosidase Inhibitory Activity of Ponkoranol and Kotalanol Desulfate

Masayuki Yoshikawa,* Fengming Xu, Seikou Nakamura, Tao Wang, Hisashi Matsuda, Genzoh Tanabe, and Osamu Muraoka

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


The methanolic extract from the roots and stems of Indian Salacia prinoides and its water-eluted fraction of Diaion HP-20 column were found to exhibit inhibitory activities against α-glucosidase. From the water-eluted fraction, two new unique constituents with thiosugar sulfonium sulfate, salaprinol (1) and ponkoranol (2), were isolated together with 10 known constituents including salacinol and kotalanol. The structures of 1 and 2 were elucidated on the basis of chemical and physicochemical evidence. Furthermore, ponkoranol (2) and kotalanol desulfate (14) were found to show potent inhibitory activities against α-glucosidase.

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Paper | Regular issue | Vol 75, No. 6, 2008, pp. 1407 - 1416
Published online: 12th February, 2008
DOI: 10.3987/COM-07-11318
Hf(OTf)4-Catalyzed 1,4-Addition Reactions of Indole to Enone in the Presence of Meso and Chiral Pyridinediamine Ligands

Sachiko Aburatani and Jun’ichi Uenishi*

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


Hf(OTf)4-catalyzed 1,4-addition reactions of indole to enones in the presence of pyridinediamine are described. Although a dimer and a trimer of indole were produced under the Hf(OTf)4 catalyzed reaction conditions of indole, the addition of pyridinediamines (La-f) inhibited such oligomerization reactions. A 1:1 mixture of Hf(OTf)4 and a pyridinediamine ligand formed a Hf(OTf)4- pyridinediamine complex, which catalyzed the 1,4-addition reaction very efficiently without the formation of dimer and trimer of indole. The stereochemistry of the pyridinediamine ligands was found to play an important role in the relative rate of the reactions.

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Paper | Regular issue | Vol 75, No. 6, 2008, pp. 1417 - 1424
Published online: 22nd February, 2008
DOI: 10.3987/COM-07-11321
Reaction of Dithiolactones with Benzyne: A Novel Synthesis of Benzo-1,3-dithioles

Kentaro Okuma,* Akiko Nojima, and Yoshinobu Yokomori

*Department of Chemistry, Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka 814-0180, Japan


The reaction of benzyne with several kinds of dithiolactones, such as β-dithiolactone (9), benzothiophene-1-thione (13), 1,2-dithiolane-3-thione (20), and 3,3,5,5-tetramethyl-4-thioxothiolane-2-thione (7), afforded benzo-1,3-dithioles in moderate to good yields, whereas the reaction of benzyne with γ-thionolactone (16) gave γ-lactone and diphenyl disulfide.

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Paper | Regular issue | Vol 75, No. 6, 2008, pp. 1425 - 1433
Published online: 15th February, 2008
DOI: 10.3987/COM-08-11322
Structure of 2,6-Dinitrophenylsulfanylethanenitrile and 2,4,6-Trinitrophenylsulfanylethanenitrile and Their Ring Closure Giving 2-Cyanobenzo[d]thiazole-3-oxides

Jirí Cerny, Valerio Bertolasi, Jirí Hanusek, and Vladimír Machácek*

*Department of Organic Chemistry, Faculty of Chemical Technology, University of Pardubice, Nám. Cs. Legií 565, CZ-53210 Pardubice, Czech Republic


The base-catalysed ring closure of 2,6-dinitrophenylsulfanyl-ethanenitrile and 2,4,6-trinitrophenylsulfanylethanenitrile gives 2-cyano-7-nitrobenzo[d]thiazole-3-oxide and 2-cyano-5,7-dinitrobenzo[d]thiazole-3-oxide, respectively. Structure of the starting phenylsulfanyl-ethanenitriles has been studied both in crystal and in solution.

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Paper | Regular issue | Vol 75, No. 6, 2008, pp. 1435 - 1446
Published online: 22nd February, 2008
DOI: 10.3987/COM-08-11338
New Phenolic Glycosides from the Leaves of Salacia chinensis

Seikou Nakamura, Yi Zhang, Tao Wang, Hisashi Matsuda, and Masayuki Yoshikawa*

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


Seven new phenolic glycosides named foliachinenosides A1 (1), A2 (2), A3 (3), B1 (4), B2 (5), C (6), and D (7), were isolated from the leaves of Salacia chinensis (Hippocrateaceae) collected in Thailand. Their structures were elucidated on the basis of chemical and physicochemical evidence.

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Note | Regular issue | Vol 75, No. 6, 2008, pp. 1447 - 1455
Published online: 15th February, 2008
DOI: 10.3987/COM-07-11291
Three New ent-Kaurane Diterpenoids from the Seeds of Pharbitis nil

Ki Hyun Kim, Mi Rim Jin, Sang Zin Choi, Mi Won Son, and Kang Ro Lee*

*Natural Products Laboratory, College of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea


Three new ent-kaurane diterpenoids, 7β, 16β, 17-trihydroxy ent-kauran 18-(6β)-olide (1), methyl 6β, 7β, 16β, 17-tetrahydroxy ent-kauran-18-oate (2) and 6β, 7β, 16β, 17-tetrahydroxy ent-kauran-18-oic acid (3), together with thirteen known compounds, were isolated from the seeds of Pharbitis nil (Convolvulaceae). The identification and structural elucidation of these compounds were based on 1D- and 2D-NMR spectral data analysis. The absolute configuration of 1 was determined by a convenient Mosher ester procedure carried out in NMR tube.

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Note | Regular issue | Vol 75, No. 6, 2008, pp. 1457 - 1466
Published online: 15th February, 2008
DOI: 10.3987/COM-07-11305
Metalloreceptors Composed of Organopalladium Complexes Containing 5-Mercapto-3H-1,3,4-thiadiazolin-2-ones

Nam Sook Cho,* Sang Beom Kim, Min Hye Kim, Seong Gyun Park, Sung Kown Kang, Se Jin Lee, and Yeong-Joon Kim

*Department of Chemistry, Chungnam National University, Daejeon, 305-764, Korea


Macrocyclic ligands containing two 5-mercapto-3H-1,3,4-thiadiazoline-2-one groups and one 1,3-benzenedimethanethiol group, which served to link the 2- and 5-positions of the heterocycle unit and chelate palladium ion, respectively, were synthesized by regiospecific S-alkylation of 5-ethoxy-3H-1,3,4-thiadiazoline-2-thione. The structures of the resulting metalloreceptors were established using 1H and 13C NMR, FTIR spectroscopy, MS spectrometry, and elemental analysis. The molecular recognition ability of the metalloreceptors was examined against DNA/RNA nucleobases and acetanilide. The complexa- tion strength of both compounds increased in the order acetanilide/uracil/thymine < adenine < cytosine.

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Note | Regular issue | Vol 75, No. 6, 2008, pp. 1467 - 1477
Published online: 12th February, 2008
DOI: 10.3987/COM-07-11309
Synthesis and Affinity Evaluation for AT1 Receptor of Phenylsalicylaldoxime-Derivatives Structurally Related to Sartans

Simona Rapposelli,* Serena Cuboni, Maria Digiacomo, Antonio Lucacchini, Filippo Minutolo, Maria Letizia Trincavelli, and Aldo Balsamo

*Department of Medicinal Chemistry, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy


In this work we reported the synthesis of new potential AT1 antagonists through the replacement of the biphenyltetrazole portion of the losartan with biphenylaldoximic (2) and phenylsalicylaldoximic (3a) moieties. Moreover, also the trifluoromethylpyrazole analogue of 3a (3b) was prepared. The new compounds synthesized were evaluated for their AT1 affinity through binding assay carried out on rat liver membranes using [125I]Sar1,Ile8-angiotensina II as radioligand.

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Note | Regular issue | Vol 75, No. 6, 2008, pp. 1479 - 1488
Published online: 15th February, 2008
DOI: 10.3987/COM-07-11311
A Convenient Synthesis of Novel Series of 4-Cyclohexyl-2-substituted [1,2,4]Triazolo[1,5-a]quinazolin-5(4H)-ones. Novel Isomers of H1 Antihistaminic Activite Agents

Ahmad S. Shawali,* Hamdi M. Hassaneen, and Nabil K. Shurrab

*Department of Chemistry, Faculty of Science, University of Cairo, Giza, 12613, Egypt


A novel series of 2,4-disubstituted-1,2,4-triazolo[1,5-a]-quinazolin-5(4H)-ones were prepared by Dimroth rearrangement of their respective isomers namely 1,4-disubstituted[1,2,4]triazolo[4,3-a]-quinazolin-5(4H)-ones. The latter were prepared via new synthetic strategy based on 1,5-elecrocyclization of the respective N-(4-oxo-3-cyclohexylquinazolin-2-yl)nitrilimines.

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Note | Regular issue | Vol 75, No. 6, 2008, pp. 1489 - 1492
Published online: 22nd February, 2008
DOI: 10.3987/COM-07-11319
One-Pot Synthesis of Purinylpurine-2,6-diones

Virendra S. Yadava,* Shiv. S. Yadav, and Neeraj Singh

*Department of Chemistry,University of Lucknow, Lucknow-226007, India


Three new purinyl purine-2,6-diones have been synthesized in one-pot reaction.

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Note | Regular issue | Vol 75, No. 6, 2008, pp. 1493 - 1501
Published online: 22nd February, 2008
DOI: 10.3987/COM-08-11328
Stereoselective Synthesis of a Novel Chiral Piperazine

Satoshi Kojima,* Takashi Chabayashi, Yasuhiro Umeda, Akihisa Iwamoto, Kazuhisa Tanabe, and Katsuo Ohkata

*Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan


(2S,6S)-2,4,6-Tris(phenylmethyl)piperazine was prepared in 11 steps and 53% overall yield from S-phenylalanine. Key steps in the synthesis involved reductive amination to introduce an ethoxycarbonylmethyl group on to the secondary nitrogen of the product and selective alkylation to introduce a benzyl group with complete diastereoselectivity.

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Note | Regular issue | Vol 75, No. 6, 2008, pp. 1503 - 1509
Published online: 15th February, 2008
DOI: 10.3987/COM-08-11344
New Diacylated Delphinidin 3-Rutinoside-5-glucosides Isolated from the Blue-Purple Flowers of Browallia speciosa

Kenjiro Toki,* Norio Saito, Atsushi Shigihara, and Toshio Honda

*Laboratory of Floriculture, Minami Kyusyu University, Takanabe, Miyazaki 844-0003, Japan


Two new diacylated delphinidin 3-rutinoside-5-glucosides were isolated from the blue-purple flowers of Browallia speciosa cv. ‘Purple’. As a major anthocyanin (1), delphinidin 3-O-[6-O-(4-O-(trans-caffeoyl)-α-L-rhamnopyranosyl)-β-D-glucopyranoside]-5-O-[2-O-(trans-p-coumaroyl)-β-D- glucopyranoside] was determined by chemical and spectroscopic methods. Another one was tentatively assigned to be the cis-p-coumroyl isomer of the major anthocyanin due to its small amount available. In the pigment 1, the 5-glucose residue of the anthocyanin is acylated with p-coumaric acid at 2-OH group of the sugar moiety, and this acylation pattern is the first report in plants.

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18 data found. 1 - 18 listed