Special Issue

Ryoji Noyori's Special Issues, Vol. 76, No. 2, 2008

63 data found. 31 - 60 listedFirst Previous Next Last
Paper | Special issue | Vol 76, No. 2, 2008, pp. 1205 - 1217
Published online: 22nd May, 2008
DOI: 10.3987/COM-08-S(N)82
A Convenient Synthesis of Fluorine-Containing Dihydrobenzo[b][1,4]diazepinols and Its Application to a Synthesis of Novel N-Sulfinylanilines

Norio Ota, Takehisa Tomoda, Naoya Terai, Yasuhiro Kamitori,* Dai Shibata, Maurice Médebielle, and Etsuji Okada*

*Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan

Abstract

The reactions of 1,1,1,5,5,5-hexafluoro-3-(isobutoxymethylene)-pentane-2,4-dione (1) with various benzene-1,2-diamines gave 2,5-dihydro-3-trifluoroacetyl-2-trifluoromethyl-1H-benzo[b][1,4]diazepines (5) in moderate to high yields under very mild conditions. Also, 2,5-dihydro-3-perhaloalkanoyl-2-perhaloalkyl-1H-benzo[b][1,4]diazepines (7) were synthesized successfully by quite similar manner. Reactions of thus obtained dihydrobenzo[b][1,4]diazepinols (5) with thionyl chloride gave unexpected novel fluorine-containing N-sulfinylanilines (9).

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1219 - 1235
Published online: 2nd June, 2008
DOI: 10.3987/COM-08-S(N)83
Synthesis, Structure, and Cholinergic Effect of Novel Neuroprotective Compounds Bearing the Tacrine Pharmacophore

Slávka Hamul’aková, Pavol Kristian,* Daniel Jun, Kamil Kuca, Ján Imrich, Ivan Danihel, Stanislav Böhm, and Karel D. Klika

*Institute of Chemistry, Faculty of Science, P. J. Safárik University, SK-041 67 Kosice, Slovak Republic

Abstract

Novel tacrine congeners with side ligands suitable for optimal interaction with the peripheral and catalytic sites of acetyl- and butyrylcholinesterase (AChE and BuChE) have been synthesized using either 9-isothiocyanato-1,2,3,4-tetrahyhroacridine or 9-chloro-1,2,3,4-tetrahydroacridi- ne which represent convenient synthons by reaction with various substituted amines. The synthesized compounds were tested for their inhibition of AChE and BuChE whereby a morpholine and a furfuryl derivative were found to be the most potent AChE and BuChE inhibitors, respectively, with the latter compound comparable in activity to tacrine.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1237 - 1248
Published online: 22nd May, 2008
DOI: 10.3987/COM-08-S(N)86
Synthesis of 1’,2’,3’,4’,5’-Pentamethyl-3,4-diphenylazaferrocene and Its Enantioselective C-2 Functionalization via (-)-Sparteine-Mediated Lithiation

Tsutomu Fukuda, Yasuyuki Koga, and Masatomo Iwao*

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

Abstract

Lithiation of 1’,2’,3’,4’,5’-pentamethyl-3,4-diphenylazaferrocene (9) with sec-BuLi/(-)-sparteine (2) in Et2O at -78 °C followed by quenching with electrophiles gave the C-2 functionalized azaferrocenes (17) in good enantioselectivities (up to 79% ee). In contrast, treatment of 9 with tert-BuLi/(-)-sparteine (2) leaded to lateral lithiation at the methyl group of cyclopentadienyl ring.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1249 - 1259
Published online: 19th May, 2008
DOI: 10.3987/COM-08-S(N)84
Selective Halogen Dance Reactions at 5,5’-Dibromo-2,2’-bithiophene

Roman Bobrovsky, Christian Hametner, Wolfram Kalt, and Johannes Fröhlich*

*Vienna University of Technology, Institute of Applied Synthetic Chemistry,
Getreidemarkt 9/163, 1060 Vienna, Austria

Abstract

Selective single and double halogen migrations were achieved at 5,5’-dibromo-2,2’-bithiophene by varying the amount of lithiation reagent, and a number of tri- and tetrasubstituted bithiophenes was obtained by quenching the lithio intermediates with various electrophiles. Some of the mono-rearranged products were subjected to a second migration in order to introduce two different substituents. Finally, the potential of the resulting compounds to undergo lithium¬induced ring opening reactions was demonstrated on a few examples.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1261 - 1270
Published online: 26th May, 2008
DOI: 10.3987/COM-08-S(N)92
Rhodium-Catalyzed Intramolecular Cycloaddition of Cyclopropene-ynes Triggered by Carbon-Carbon Bond Cleavage

Takanori Shibata,* Shunsuke Maekawa, and Kohei Tamura

*Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Shinjuku, Tokyo, 169-8555, Japan

Abstract

In the presence of a catalytic amount of RhCl(PPh3)3, an intramolecular cycloaddition of cyclopropene-yne proceeded along with carbon-carbon bond cleavage of cyclopropene ring to give various bicyclic cyclopentadiene derivatives in good to high yield.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1271 - 1283
Published online: 26th May, 2008
DOI: 10.3987/COM-08-S(N)93
Iridium Catalyzed Enantioselective Hydrogenation of N-Iminopyridinium Ylides: Mechanistic Insights

Claude Y. Legault, André B. Charette,* and Pier G. Cozzi

*Département de Chimie, Université de Montréal, P.O. Box 6128, Station Downtown, Montréal, Québec, H3C 3J7, Canada

Abstract

Mechanistic insights of the efficient iridium catalyzed asymmetric hydrogenation of N-iminopyridinium ylides are reported. Using NMR and mass spectrometry, the nature of the pre-catalyst and role of iodine was studied. The effect of solvent as well as an extensive ligand screening is presented. Deuteration experiments also show that C-H(D) insertion pathways occur in competition with the hydrogenation process.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1285 - 1300
Published online: 22nd May, 2008
DOI: 10.3987/COM-08-S(N)94
Asymmetric Hetero Diels-Alder Reaction of Nitroso Compounds Utilizing Tartaric Acid Ester as a Chiral Auxiliary

Hiroki Sakai, Xia Ding, Tetsusuke Yoshida, Shuhei Fujinami, Yutaka Ukaji,* and Katsuhiko Inomata*

*Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan

Abstract

The regio- and enantioselective hetero Diels-Alder reaction of a nitroso compound with a cyclic dienol, cyclohexa-1,3-dienylmethanol, has been realized utilizing stoichiometric amount of tartaric acid ester as a chiral auxiliary to afford the corresponding dihydro-1,2-oxazine with complete regioselectivity and high enantioselectivity of up to 92% ee. A catalytic version of the asymmetric hetero Diels-Alder reaction of nitroso compounds with the dienol was also achieved to afford the corresponding optically active cycloadducts with up to 83% ee. The addition of MS 4A was crucial to realize reproducible high enantioselectivity.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1301 - 1312
Published online: 19th May, 2008
DOI: 10.3987/COM-08-S(N)95
Development of Column-Free Alkoxycarbonyl, Aryloxycarbonyl, and Acyl Transfer Reagents

Mamoru Shimizu and Mikiko Sodeoka*

*Synthetic Organic Chemistry Laboratory, RIKEN (The Institute of Physical and Chemical Research), 2-1, Hirosawa, Wako, 351-0198, Japan

Abstract

Easy-to-handle alkoxycarbonyl, aryloxycarbonyl, and acyl transfer reagents, which contain 3-nitro-1,2,4-triazole (NT) as a leaving group, were developed. With these reagents (NT reagents), which are stable nonhygroscopic crystalline materials, the reactions can be accomplished in about 5 min, and product can be isolated without tedious column chromatographic purification.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1313 - 1328
Published online: 19th May, 2008
DOI: 10.3987/COM-08-S(N)96
2,6-Dimethyl-4-nitrobenzoic Anhydride (DMNBA): An Effective Coupling Reagent for the Synthesis of Carboxylic Esters and Lactones

Isamu Shiina* and Ryo Miyao

*Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 Japan

Abstract

Various carboxylic esters are obtained at room temperature in excellent yields with high chemoselectivities from nearly equimolar amounts of carboxylic acids and alcohols using 2,6-dimethyl-4-nitrobenzoic anhydride with triethylamine by the promotion of 4-(dimethylamino)pyridine. The efficiency of the esterification is compared to those of other dehydrations using substituted benzoic anhydrides as coupling reagents. This method was successfully applied to the synthesis of threo-aleuritic acid lactone and the desired 17-membered ring compound was prepared in high yield at room temperature from the corresponding free trihydroxycarboxylic acid using 2,6-dimethyl-4-nitrobenzoic anhydride in the presence of 4-(dimethylamino)pyridine.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1329 - 1335
Published online: 2nd June, 2008
DOI: 10.3987/COM-08-S(N)99
A Convenient Synthesis of Optically Active Biopterin

Yuichi Shiro, Fumi Urano, Yasuhiro Kuroda, and Shizuaki Murata*

*Graduate School of Environmental Studies, Nagoya University, Chikusa, Nagoya, 464-8601 Japan

Abstract

Naturally occurring L-erythro-biopterin is synthesized using regioselective pteridine-ring formation from the chiral α,β-epoxyaldehyde intermediate which is prepared from ethyl L-lactate via Sharpless epoxidation.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1337 - 1360
Published online: 19th May, 2008
DOI: 10.3987/COM-08-S(N)100
Synthesis of 2’-Deoxy-4’-C-hydroxymethyl-4’-thioribonucleosides and Their 2’,3’-Dideoxy and 2’,3’-Didehydro-2’,3’-dideoxy Analogues

Junzo Nokami,* Masayuki Mae, Satoshi Fukutake, Tomoyuki Ubuka, and Mitsuhiro Yamada

*Department of Applied Chemistry, Faculty of Engineering, Okayama University of Science, 1-1 Ridai-cho, Okayama 700-0005, Japan

Abstract

(±)-2’-Deoxy-4’-C-hydroxymethyl-4’-thioribonucleosides (1) and their 2’,3’-dideoxy- (2) and 2’,3’-didehydro-2’,3’-dideoxy- (3) analogues have been prepared from hydrothiophene derivatives 2,2-bis(benzyloxymethyl)-3-benzyloxytetrahydrothiophene (4), 2,2-bis(acetoxymethyl)tetrahydrothiophene (5) and 2,2-bis(acetoxymethyl)-2,5-dihydrothiophene (6), respectively. Preparation of the compound 1 has been carried out via N-glycosylation of the corresponding sulfoxide 9, derived from 4 by m-CPBA oxidation, with trimethylsilylated pyrimidines and trimethylsilyl triflate (Kita-O’Niel-Matsuda’s method; modified Pummerer rearrangement). On the other hand, the compounds 2 and 3 have been obtained via N-glycosylation of the corresponding 4’-thiofuranoses 7 and 8 with trimethylsilylated pyrimidines and SnCl4, respectively, while the compounds 7 and 8 have been prepared from compounds 5 and 6 by an electrochemical 2-acetoxylation, respectively.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1361 - 1367
Published online: 5th June, 2008
DOI: 10.3987/COM-08-S(N)101
Influence of the Position of tert-Butyl Substituents on Reactivity of Quinone Dimers Yielding Dibenzofuran-1,4-diones

Naoto Hayashi,* Akifumi Kanda, Hiroyuki Higuchi, and Keiko Ninomiya

*Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama 930-8555, Japan

Abstract

Reactivity of two isomeric quinone dimers, 5,5’-di-tert-butyl-2,2’-bisbenzoquinone (2) and 6,6’-di-tert-butyl-2,2’-bisbenzoquinone (3) have been compared. Both quinone dimers underwent thermal cyclization in ethanol to give dibenzofuran-1,4-diones exclusively, the reaction proceeding faster for 3 than for 2. Molecular modeling analysis indicates that the different reactivity should be explained in terms of the steric hindrance of tert-butyl group in 2, which prevents approaching of solvent molecules to C=O moiety so that the solvent-assisted proton transfer occurs more slowly.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1369 - 1380
Published online: 7th July, 2008
DOI: 10.3987/COM-08-S(N)102
The MCD Spectroscopy of Corrolazines and Triazatetrabenzocorroles

John Mack, Masaru Bunya, David Lansky, David P. Goldberg,* and Nagao Kobayashi*

*Department of Chemistry, Faculty of Graduate Science, Tohoku University, Sendai 980-8578, Japan

Abstract

We report the first MCD spectral data for free base corrolazine and a transition metal corrolazine complex. A detailed analysis of the MCD and UV-visible absorption spectroscopy of these compounds and phosphorous corrolazine and triazatetrabenzocorroles is carried out based on the results of TD-DFT calculations and an application of Michl’s perimeter model.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1381 - 1399
Published online: 26th May, 2008
DOI: 10.3987/COM-08-S(N)104
Diastereoselective Nucleophilic Cyclopropanation of 1,2-Diketones and α-Ketoimines with Bis(iodozincio)methane

Kenichi Nomura, Keisuke Asano, Takuya Kurahashi, and Seijiro Matsubara*

*Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoutodaigaku-katsura, Nishikyo-ku, Kyoto 615-8510, Japan

Abstract

A reaction of 1,2-diketones and α-ketoimines with bis(iodozincio)methane gave cyclopropan-1,2-diol and 2-aminocyclopropanol respectively via nucleophilic [2+1]cycloaddition. The reaction proceeded via a sequential nucleophilic attack of the dizinc reagent to vicinal two carbonyl group. The reaction showed high diastereoselectivity to give cis-isomer via a face-to-face coordination between the substrate and bis(iodozincio)methane.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1401 - 1423
Published online: 26th June, 2008
DOI: 10.3987/COM-08-S(F)12
Triphenylphosphoranylidene Substituted Heterocycles as Versatile Intermediates

Alan R. Katritzky,* Adam S. Vincek, and Peter J. Steel

*Center for Heterocyclic Compounds, University of Florida, Department of Chemistry, Gainesville, Florida 32611-7200, USA

Abstract

N-Cbz-(α-aminoacyl)benzotriazoles 5a-e reacted with (stabilized-methylene)triphenylphosphoranes 6 and 13 to give the corresponding esters 7a-e (66-91%) or nitriles 14a-e (63-85%). Deprotection of N-Cbz-γ-amino-β-oxo-α-triphenylphosphoranylidene esters 7a-d induced cyclization to form 2,4-dioxo-3-triphenylphosphoranylidene pyrrolidines 9a-c (20-98%) and 1,3-dioxo-2-triphenylphosphoranylidene tetrahydropyrrolizine 9d (79%). N-Cbz-δ-amino-β-oxo-α-triphenylphosphoranylidene ester 7e cyclized to form 2,4-dioxo-3-triphenylphosphoranylidene piperidine 9e (60%). Deprotection of N-Cbz-γ-amino-β-oxo-α-triphenylphosphoranylidene nitriles 14a-d similarly formed 5-amino-4-triphenylphosphonio-2,4-dihydropyrrol-3-one bromides 15a-c (70-72%) and 3-ammonio-2-triphenylphosphoniotetrahydro- pyrrolizin-1-one dibromide 15d (66%). N-Methyl pyrrolidine 11 was transformed into 3,3-dibromopyrrolidin-2,4-dione 16 (79%), 3,3-dibromo-5- hydroxypyrrolidin-2,4-dione 17 (88%), 4-azido-3-bromopyrrol-2-one 18 (84%), and 4-benzotriazol-1-ylpyrrol-2-one 19 (92%).

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1425 - 1438
Published online: 19th June, 2008
DOI: 10.3987/COM-08-S(N)108
Synthesis and Evaluation of Isomers of Melleumin B from the Myxomycete Physarum melleum; an Approach for Wnt Signal Inhibitor Trusted in Nature

Midori A. Arai, Yujiro Uchino, Shuwa Hanazawa, Xiaofan Li, Naoki Kimura, and Masami Ishibashi*

*Graduate School of Pharmaceutical Science, Chiba University, Chiba 263-8522, Japan

Abstract

Two stereoisomers of melleumin B (1), seco acid methyl ester of melleumin A (2), which are novel peptide compounds isolated from the myxomycete Physarum melleum, were synthesized and evaluated for their inhibition of Wnt signal transcription. The 3R-epimer and (3R, 4S, 10R, 11R)-isomer of 1 showed moderate inhibition of the Wnt signal.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1439 - 1470
Published online: 26th June, 2008
DOI: 10.3987/COM-08-S(N)109
Novel Substituted Tetrathia[7]helicenes by Direct Functionalization of the Helical System or Photocyclization of Substituted 1,2-(Bis-benzodithienyl)ethenes

Clara Rigamonti, Maria Teresa Ticozzelli, Alberto Bossi, Emanuela Licandro,* Clelia Giannini, and Stefano Maiorana*

*Department of Organic and Industrial Chemistry, University of Milan, via Venezian, 21 I-20133 Milan, Italy

Abstract

In this work we report the synthesis of several new tetrathia[7]helicenes ([7]THs) functionalized with different electron-donor (ED) and electron-acceptor (EA) substituents in the positions 2,13 (the α positions of terminal thiophene rings) and/or 7,8 (on the central arene ring of the helical system). Some substituents were chosen on the basis of theoretical calculations performed on [7]THs to predict the best groups for applications in optoelectronics; some others were conceived to endow helicenes with appropriate groups in view of their insertion into polymeric structures.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1471 - 1484
Published online: 19th June, 2008
DOI: 10.3987/COM-08-S(N)110
Electrooxidative Desulfurization/Chlorination. A Facile Synthesis of 4-Chloro-2-azetidinones, a Potent Intermediate for Carbapenems

Manabu Kuroboshi, Masayoshi Miyada, Syoichi Tateyama, and Hideo Tanaka*

*Department of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 3-1-1, Okayama 700-8530, Japan

Abstract

(3S,4R)-3-(1’(R)-tert-Butyldimethylsilyloxyethyl)-4-chloro-2-azetidinone (2), a potent intermediate for the synthesis of carbapenem antibiotics, was synthesized by thermal ring opening/acylation of (3S,5R,6S)-6-(1’(R)-tert-butyldimethylsilyloxyethyl)penicillanate S-oxide (8) leading to 4-acylthio-2-azetidinone derivative 9 and subsequent removal of the N-substituent followed by electrooxidative desulfurization/chlorination of the C(4)-acylthio moiety.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1485 - 1495
Published online: 30th June, 2008
DOI: 10.3987/COM-08-S(N)112
Construction of Chiral Quaternary Carbon Centers via Palladium-Catalyzed Asymmetric Deconjugative Allylation

Hiroki Yamamoto, Yoshihiro Oonishi, and Yoshihiro Sato*

*Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan

Abstract

A Pd(0)-catalyzed asymmetric deconjugative allylation of various Knoevenagel products and allylic compounds was investigated. It was found that various compounds, having a quaternary carbon center directly attached to sp2-carbon centers including a 1,3-diene moiety, could be synthesized through this methodology, although the yield and enantiomeric excess varied from low to modest depending on the structure of substrates and the reaction conditions.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1497 - 1509
Published online: 12th June, 2008
DOI: 10.3987/COM-08-S(N)114
Synthesis of Tetrahydroisoquinoline Antitumor Natural Products: Construction of Tricyclic Lactams Through Pictet-Spengler-Type Cyclization of N-Methyl-3-arylmethylpiperazine-2,5-dione with Ethyl Diethoxyacetate

Masashi Yokoya, Osamu Kawachi, and Naoki Saito*

*Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan

Abstract

6-Hydroxymethyl-7,8,10-trimethoxy-2,6-dimethyl-3,6,11,11a-tetrahydro-2H-pyrazino[1,2-b]isoquinoline-1,4-dione (10) was prepared stereoselectively by Pictet-Spengler-type cyclization of the N,O-acetal of 3-arylmethylpiperazine-2,5-dione (8) in high yield. This procedure provides an efficient route for the total synthesis of renieramycin G and cribrostatin 4.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1511 - 1524
Published online: 7th August, 2008
DOI: 10.3987/COM-08-S(N)115
Synthesis of Substituted Aziridines via Intramolecular Reaction of β-N-Chloroethylamino Carbanions

Mieczyslaw Makosza,* Karolina Bobryk, and Dariusz Krajewski

*Institute of Organic Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw, Poland

Abstract

Simple and efficient method of synthesis of 2-alkoxycarbonyl, 2-cyano, 2-phenylsulfonyl N-alkylaziridines was elaborated via intramolecular nucleophiles substitution of chloride in 1-N-chloro-2-alkoxycarbonyl (cyano, phenylsulfonyl) ethyl amines. These substituted N-chloroamines are readily erasable via N-chlorination of the adducts of primary amines to Michael acceptors.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1525 - 1535
Published online: 28th July, 2008
DOI: 10.3987/COM-08-S(N)116
Benzophenone-Derived Catalyst with Self-Adaptation: Highly Enantioselective Hydrogenation Irrespective of Ketone Substrates

Kazuki Wakabayashi, Kohsuke Aikawa, and Koichi Mikami*

*Department of Applied Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan

Abstract

The Ru complex with the tropos benzophenone-derived diphosphine ligand could be chirally controlled to a single chiral conformation instantaneously with a chiral diamine to attain high enantioselectivity in the asymmetric hydrogenation irrespective of ketone substrates. In the asymmetric hydrogenation of not only 1-acetonaphthone but also 9-acetylanthracene, the tropos Ru complex fits well with the substrate change to give high catalytic activity and enantioselectivity upon addition of silver salts such as AgOTf.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1537 - 1547
Published online: 23rd June, 2008
DOI: 10.3987/COM-08-S(N)118
Enantioselective Synthesis of Both Enantiomers of Etodolac via a Lipase-Catalyzed Kinetic Resolution

Shuji Akai,* Hiroyuki Nemoto, and Masahiro Egi

*School of Pharmaceutical Sciences, University of Shizuoka 52-1, Yada, Suruga-ku, Shizuoka, Shizuoka 422-8526, Japan

Abstract

The efficient preparation of both enantiomers of etodolac 1 was achieved by the lipase-catalyzed kinetic resolution of the racemic primary alcohol (±)-2 followed by chemoselective oxidation.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1549 - 1559
Published online: 5th June, 2008
DOI: 10.3987/COM-08-S(N)119
De Novo Asymmetric Approaches to 2-Amino-N-(benzyloxycarbonyl)-1-(2’-furyl)ethanol and 2-Amino-N-(tert-butoxycarbonyl)-1-(2’-furyl)ethanol

Michael H. Haukaas, Miaosheng Li, Alexey M. Starosotnikov, and George A. O’Doherty*

*Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA

Abstract

Several methods were investigated for the de novo asymmetric synthesis of 2-amino-N-(benzyloxycarbonyl)-1-(2’-furyl)ethanol and 2-amino-N-(tert-butoxycarbonyl)-1-(2’-furyl)ethanol. A five step procedure was developed for the practical preparation of optically pure 2-amino-N-(benzyloxycarbonyl)-1-(2’-furyl)ethanol and a shorter 2-step procedure was developed for 2-amino-N-(tert-butoxycarbonyl)-1-(2’-furyl)ethanol. Both routes used a Noyori reduction to install the asymmetry.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1561 - 1569
Published online: 7th July, 2008
DOI: 10.3987/COM-08-S(N)120
Inhibition of NF-Kappa B Activation by Penicillic Acid and Dihydropenicillic Acid Isolated from Fungi

Miyuki Tachibana, Chino Matsui, Yoshinori Takeuchi, Eriko Suzuki, and Kazuo Umezawa*

*Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-0061, Japan

Abstract

In the course of our screening of NF-κB inhibitors from microbial secondary metabolites, we isolated two 2(5H)-furanones, penicillic acid and dihydropenicillic acid, from the culture filtrate of Penicillium. Both penicillic acids inhibited LPS-induced NO production and NF-κB activation. They did not inhibit protein synthesis. Interestingly, penicillic acid inhibited advanced glycation end product (AGE)-induced NO production.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1571 - 1575
Published online: 26th June, 2008
DOI: 10.3987/COM-08-S(N)122
Xestosaprol C, a New Pentacyclic Hydroquinone Sulfate from a Marine Sponge Xestospongia sapra

Takaaki Kubota, Yuji Kon, and Jun’ichi Kobayashi*

*Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan

Abstract

A new pentacyclic hydroquinone sulfate with a 2,5-dihydro-2,5-furandiol ring, xestosaprol C (1), has been isolated from an Okinawan marine sponge Xestospongia sapra. The structure of 1 was elucidated by the spectroscopic data.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1577 - 1584
Published online: 19th June, 2008
DOI: 10.3987/COM-08-S(N)124
Free Radical Tandem Addition-Cyclization of Te-Phenyl N,N-Dimethylcarbamotelluroate to 1,6-Enynes

Shin-ichi Fujiwara,* Yoshihiko Shimizu, Yoshimasa Makita, Tsutomu Shin-ike, and Nobuaki Kambe*

*Department of Chemistry, Osaka Dental University, Hirakata, Osaka 573-1121, Japan

Abstract

Free radical tandem addition of Te-phenyl N,N-dimethyl- carbamotelluroate (1) to alkenes and alkynes was examined. Simple addition of carbamotelluroate 1 to alkenes such as styrene and methyl acrylate did not take place under irradiation of visible light. However, when alkynes were added to this system, photo-induced three-component radical coupling proceeded to give alkenyl tellurides 6 in moderate yields. This reaction could be applied to heterocycles synthesis by use of 1,6-dienes 7. Carbamotelluroate 1 added to allyl propargyl ethers or an amine 7 under light giving rise to tetrahydrofuran or pyrrolidine 8 by tandem radical addition/cyclization reaction.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1585 - 1592
Published online: 7th July, 2008
DOI: 10.3987/COM-08-S(N)125
The NCN-Type Pincer Complex of Palladium(II) with a 2,6-Bis(2-pyridyl)-4-tert-butylbenzene Tridentate Ligand: Synthesis, Structure and Catalytic Activity in the Mizoroki-Heck Reaction

Yuichi Hirano, Yuji Saiki, Hideki Taji, Shiro Matsukawa, and Yohsuke Yamamoto*

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

Abstract

The reaction of 1-bromo-4-tert-butyl-2,6-diiodobenzene with 2-pyridylzinc chloride in the presence of catalytic Pd(PPh3)4 afforded an NCN-type pincer palladium(II) complex with two pyridine donors. The structure of the complex was determined by X-ray crystallography. The complex was found to catalyze the Mizoroki-Heck reaction at 250 °C under aerobic conditions.

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Paper | Special issue | Vol 76, No. 2, 2008, pp. 1593 - 1606
Published online: 7th August, 2008
DOI: 10.3987/COM-08-S(N)126
Asymmetric Dieckmann Condensation via Memory of Chirality: Synthesis of the Key Intermediate for AS-3201, an Aldose Reductase Inhibitor

Toshihide Watanabe and Takeo Kawabata*

*Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan

Abstract

Asymmetric Dieckmann condensation via memory of chirality has been developed. A key intermediate for the synthesis of AS-3201, an aldose reductase inhibitor, has been prepared in 94% ee by asymmetric Dieckmann condensation of 8 derived from L-aspartic acid.

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Note | Special issue | Vol 76, No. 2, 2008, pp. 1607 - 1615
Published online: 16th June, 2008
DOI: 10.3987/COM-08-S(N)79
Synthesis of Oriented Anti-Virus 7-O-Substituted Apigenins

Kin-ichi Oyama, Tadao Kondo, and Kumi Yoshida*

*Graduate School of Inforamtion Science, Nagoya University, Chikusa, Nagoya 464-8601, Japan

Abstract

7-O-Substituted apigenins were synthesized for searching anti-virus active compound. Using a commercially available naringenin as a starting material, 7-O-methylapigenin (1) and seven unnatural 7-O-substituted apigenin derivatives (13-19) were prepared via 4’-O-methoxymethylapigenin (5) as an intermediate.

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