Special Issue

Albert Padwa's Special Issues, Vol. 84, No. 2, 2012

55 data found. 31 - 55 listedFirst Previous
Paper | Special issue | Vol 84, No. 2, 2012, pp. 1171 - 1178
Published online: 7th October, 2011
DOI: 10.3987/COM-11-S(P)98
A New Derivative of Galanthamine: Methylene Insertion into the Aromatic Ring in Place of Cyclopropanation

Péter Keglevich, Péter Kovács, László Hazai, Zsuzsanna Sánta, Zsófia Dubrovay, Viktor Háda, Csaba Szántay, Jr., György Kalaus, and Csaba Szántay*

*Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, H-1111 Budapest, Szt. Gellért tér 4, Hungary

Abstract

In the course of the reaction between galanthamine and diazomethane in the presence of a catalyst, such as palladium(II) acetate or copper(I) bromide, methylene insertion into the aromatic ring was observed instead of the expected cyclopropanation of the carbon-carbon double bond.

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Paper | Special issue | Vol 84, No. 2, 2012, pp. 1179 - 1191
Published online: 20th October, 2011
DOI: 10.3987/COM-11-S(P)100
Synthesis of Aza-Surfactin and 3-Epi-Aza-Surfactin

Yi-Lin Huang, Raphael Frey, M. Elisa Juarez-Garcia, and Jeffrey W. Bode*

*Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich, Switzerland

Abstract

Two synthetic approaches to aza-surfactins are reported. In the first, our recently developed synthesis of unnatural β3-amino acids was used to prepare the requisite monomer, which was used in solid phase peptide synthesis, and followed by macrolactamization of a partially protected precursor. In the second, the corresponding β3-N-hydroxyaminoacid was used to prepare a fully unprotected cyclization precursor that was closed to give 3-epi-aza-surfactin by the first example of cyclization by the α-ketoacid–hydroxylamine amide formation.

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Paper | Special issue | Vol 84, No. 2, 2012, pp. 1193 - 1207
Published online: 28th October, 2011
DOI: 10.3987/COM-11-S(P)101
Synthetic Studies on MPC1001: A Dipolar Cycloaddition Approach to the Pyrrolidine Ring System

Paul T. Schuber and Robert M. Williams*

*Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, U.S.A.

Abstract

A novel [1,3]-dipolar azomethine ylide cycloaddition has been developed in an approach to the synthesis of the MPC1001 family of natural products.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1209 - 1216
Published online: 8th June, 2011
DOI: 10.3987/COM-10-S(P)2
New Hydrazine-Based Organocatalyst for Asymmetric Diels-Alder Reaction of 1,2-Dihydropyridines

Yuko Okuyama, Kenichi Osone, Hiroto Nakano, and Mitsuhiro Takeshita*

*Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan

Abstract

Chiral hydrazinoalcohol organocatalyst is designed and synthesized as a new organocatalyst for the enantioselective Diels-Alder reaction between 1,2-dihydropyridines and acrolein derivatives to produce an optical active isoquinuclidine derivative (up to 67% ee with up to 96% yield).

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1217 - 1226
Published online: 26th May, 2011
DOI: 10.3987/COM-11-S(P)11
Access to Some UV Chromophore-Containing Antimalarial Trioxanes Using Hydrogen Peroxide as Source of the Peroxy Bonds

Yun Li, Sergio Wittlin, and Yikang Wu*

*State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, 345 Lingling Road, Shanghai 200032, China

Abstract

Several trioxanes were synthesized through perhydrolysis of an allylic epoxide followed by ketal exchange with a proper dimethyl ketal.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1227 - 1233
Published online: 3rd June, 2011
DOI: 10.3987/COM-11-S(P)14
Formal Synthesis of (-)-Clavepictine A and (+)-Clavepictine B from a Sulfinimine (N-Sulfinylimine)-Derived Chiral Building Block

Franklin A. Davis* and He Xu

*Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA 19122, U.S.A.

Abstract

The sulfinimine-derived chiral building block trans-2,6-disubstituted 1,2,5,6-tetrahydropiperidine (+)-5 was employed in a concise formal asymmetric synthesis of the cytotoxic marine alkaloids clavepictines (-)-A and (+)-B (1a and 1b). This synthesis is highlighted by a highly diastereoselective hydroboration-oxidation reaction to install the C-3 hydroxyl group.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1235 - 1244
Published online: 17th June, 2011
DOI: 10.3987/COM-11-S(P)15
A New 3-(Ethoxycarbonylmethyl)isoxazolopyridone as a Precursor to Acylpyridones

Raymond C. F. Jones,* James N. Iley, and Georgia Loizou

*Department of Chemistry, Loughborough University, Leicestershire LE11 3TU, U.K.

Abstract

A new 3-(ethoxycarbonylmethyl)isoxazolo[4,3-c]pyridin-4-one has been prepared as a potential precursor to 3-acyl-4-hydroxypyridin-2-ones, by a route involving dipolar cycloaddition of nitrile oxides derived from β-alanine with an enamino-ester.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1245 - 1250
Published online: 22nd June, 2011
DOI: 10.3987/COM-11-S(P)18
Nonactin and Related Compounds Found in a Screening Program for Wnt Signal Inhibitory Activity

Yuuya Tamai, Kazufumi Toume, Midori A. Arai, Akinori Hayashida, Hikaru Kato, Yoshikazu Shizuri, Sachiko Tsukamoto, and Masami Ishibashi*

*Department of Natural Products Chemistry, Graduate School of Pharmaceutical Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan

Abstract

A screening study using a luciferase assay to identify natural products with inhibitory activity against Wnt signaling was carried out. Fractionation of the culture extract of an actinomycete, strain CKK179, led to the identification of nonactin (1), monactin (2), and dinactin (3) as active compounds. We examined the effects of dimeric dinactin (4), isolated from another actinomycete, Streptomyces sp. (YM09-028), on Wnt signaling activity and found that 1 - 4 inhibited TCF/β-catenin transcriptional activity with IC50 values of 0.6 - 7.4 nM.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1251 - 1258
Published online: 16th June, 2011
DOI: 10.3987/COM-11-S(P)21
Synthesis of Octahydroquinolizinones Aza-Analogues of Terpenoid Skeletons

Alberto Brandi,* Franca M. Cordero, Carolina Vurchio, Massimo Lucentini, and Stefano Cicchi

*Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino (FI), Italy

Abstract

Two new ketones, 6,6,9a-trimethyl-octahydro-quinolizin-2-one and 4,4,9a-trimethyl-octahydro-quinolizin-2-one, were synthesized by regioselective 1,3-dipolar cycloaddition of tetrahydropyridine nitrones with methylenecyclopropanes followed by thermal rearrangement. The new ketones feature a structural analogy with the 5,5,8a-trimethyl-octahydro-2-naphthalene skeleton typical of terpenoid structures.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1259 - 1263
Published online: 14th July, 2011
DOI: 10.3987/COM-11-S(P)30
Sabinaperins A and B, Two New Lignans from Juniperus sabina

Jenis Janar, Alfarius Eko Nugroho, Yusuke Hirasawa, Bahargul Konirhan, and Hiroshi Morita*

*Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan

Abstract

Two new lignans, sabinaperins A (1) and B (2), have been isolated from the aerial part of Juniperus sabina L. together with six known lignans. Their structures were established on the basis of 1D and 2D-NMR data analysis.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1265 - 1270
Published online: 1st August, 2011
DOI: 10.3987/COM-11-S(P)31
Chisomicines D and E, Two New Limonoids from Chisocheton ceramicus

Ibrahim A. Najmuldeen, A. Hamid A. Hadi,* Khalit Mohamad, Khalijah Awang, Kamal Aziz Ketuly, Mat Ropi Mukhtar, Hairin Taha, Noraziah Nordin, Marc Litaudon, Françoise Guéritte, Alfarius Eko Nugroho, and Hiroshi Morita*

*Department of Chemistry, Faculty of Science, University of Malaya, Pantai Valley, 50603 Kuala Lumpur, Malaysia

Abstract

Two new limonoids, chisomicines D and E (12) have been isolated from the bark of Malaysian Chisocheton ceramicus (Miq.) C. DC. Their structures were elucidated on the basis of 1D and 2D-NMR data analysis.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1271 - 1276
Published online: 15th July, 2011
DOI: 10.3987/COM-11-S(P)36
2nd Generation Palladium-Catalyzed Cycloalkenylation in Iridoid Synthesis: Diastereoselective Total Synthesis of Isoiridomyrmecin and Isodihydronepetalactone

Kazutaka Takeda and Masahiro Toyota*

*Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 593-8531, Japan

Abstract

Two different types of iridoids, isoiridomyrmecin and isodihydronepetalactone, were diastereoselectively synthesized using a 2nd generation palladium-catalyzed cycloalkenylation as the key step.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1277 - 1284
Published online: 28th July, 2011
DOI: 10.3987/COM-11-S(P)38
A Facile and Convenient Method for the Synthesis of 6,8-Bis(trifluoroacetyl)quinolin-5-amines

Dai Shibata, Maurice Médebielle, Mizuki Hatakenaka, and Etsuji Okada*

*Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan

Abstract

New 6,8-bis(trifluoroacetyl)quinolin-5-amines (6) were easily prepared in moderate to high yields by the aromatic nucleophilic nitrogen-nitrogen exchange reaction of N,N-dimethyl-6,8-bis(trifluoroacetyl)-quinolin-5-amine (5) with various aliphatic and aromatic amines.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1285 - 1288
Published online: 21st July, 2011
DOI: 10.3987/COM-11-S(P)40
Reinvestigation of the Classical Total Synthesis of Makomakine

Makoto Furuya, Ayumi Nagatomo, and Masahiro Toyota*

*Department of Chemistry, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 593-8531, Japan

Abstract

Reinvestigation of the original Stevens synthesis of makomakine showed that the yield of the Ritter reaction of 3-indoylacetonitrile with (–)-β-pinene could be increased by employing Hg(OTf)2.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1289 - 1299
Published online: 29th August, 2011
DOI: 10.3987/COM-11-S(P)47
An Improved Synthesis of Functionalized cis-Decahydroquinolines Using a Baylis-Hillman-Type Adduct

Junfeng Huang, Jeffrey Petersen, and Stephen C. Bergmeier*

*Department of Chemistry and Biochemistry, Ohio University, Clippinger Laboratories, Athens, OH 45701-2979, U.S.A.

Abstract

An efficient and diastereoselective method to synthesize highly functionalized cis-decahydroquinolines was reported. The addition of a vinyl aluminum reagent to an aldehyde followed by an intramolecular SN2’ Mitsunobu reaction gave the desired 3,7,8-trisubstituted product designed as methyllycaconitine analogs. An unexpected tandem vinylaluminum addition and Michael reaction to produce a 4-hydroxy cis-decahydroquinoline has also been reported.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1301 - 1304
Published online: 21st July, 2011
DOI: 10.3987/COM-11-S(P)51
Practical Total Synthesis of Luotonin A by Intramolecular Double Hetero Diels-Alder Reaction

Ken Natsuki, Tadamichi Shindo, and Masahiro Toyota*

*Department of Chemistry, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 593-8531, Japan

Abstract

An intramolecular double hetero Diels–Alder reaction of N-(2-cyanoquinolin-3-ylmethyl)-2-tosyloxybenzamide (3c) provided luotonin A (2) in 82% yield. Surprisingly, N-(2-bromoquinolin-3-ylmethyl)-2-tosyloxybenzamide (4) directly provided luotonin A (2) in 78% yield in the presence of Pd2(dba)3 (5 mol %), dppf (20 mol %), and K2CO3 (6 eq).

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1305 - 1312
Published online: 2nd August, 2011
DOI: 10.3987/COM-11-S(P)52
Quinoline Fused Heterocycles from Intramolecular Cycloaddition Reactions

Giuseppe Cremonesi, Piero Dalla Croce,* Maddalena Gallanti, and Concetta La Rosa

*Department of Organic and Industrial Chemistry, Faculty of Pharmacy, University of Milano, Via Venezian 21, I-20133 Milano, Italy

Abstract

Ring fused quinoline heterocycles such as isoxazolo-, pyrrolo- and pyrazoloquinolines (7,9,11,14) have been prepared by intramolecular 1,3-dipolar cycloaddition reactions starting from the suitable intermediates. The structures of the products were assigned by means of analytical and spectroscopic data.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1313 - 1323
Published online: 11th August, 2011
DOI: 10.3987/COM-11-S(P)64
Synthesis of Ruthenium(II) 2,6-Bis(imino)pyridyl Complexes for C-H Amination of Sulfamate Esters

Jennifer L. Bon and Simon B. Blakey*

*Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322, U.S.A.

Abstract

A family of ruthenium(II) 2,6-bis(imino)pyridyl complexes have been developed as a novel catalyst framework for C-H amination. Their synthesis and evaluation is herein described. The reactivity of these catalysts is heavily dependent upon the electronics of the ligand. These complexes are capable of functionalizing the benzylic protons of sulfamate esters with good conversion.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1325 - 1334
Published online: 8th August, 2011
DOI: 10.3987/COM-11-S(P)67
Synthetic Studies on Paspaline: Lewis Acid-Mediated Sequential Construction of A-E Ring Skeleton

Kentaro Okano, Yu Yoshii, and Hidetoshi Tokuyama*

*Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan

Abstract

The common pentacyclic skeleton of indole diterpene alkaloids, paspaline and its derivatives was constructed by a sequential reaction. The appropriate choice of the protecting group on the indole nitrogen was critical for the formation of bis(methylthio)allylic alcohol, which then underwent sulfonium ion formation and intramolecular electrophilic C-C-bond formation at the indole 3-position.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1335 - 1343
Published online: 3rd August, 2011
DOI: 10.3987/COM-11-S(P)69
A Synthetic Approach to Aromatic Aminoglycoside as a Neamine Mimic

Ryo Inoue, Sho Matsuda, Yoshiki Oda, Hirofumi Ooyama, Akihiro Yoshida, Keita Hamasaki, and Takashi Yamanoi*

*The Noguchi Institute, 1-8-1, Kaga, Itabashi-ku, Tokyo 173-0003, Japan

Abstract

This paper describes the synthetic approach to an aromatic α-glycoside as a mimic of neamine, which is a common core structure of some aminoglycoside antibiotics. We achieved the synthesis of the protected precursor of the neamine mimic, 4-(2,6-diamino-2,6-dideoxy-α-D-glucopyranosyloxy)-1,3-phenylenediamine, from N-acetyl-D-glucosamine and 2,4-diaminophenol as the starting materials using a glycosylation technique.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1345 - 1353
Published online: 24th August, 2011
DOI: 10.3987/COM-11-S(P)76
Synthesis of Substituted Phenazines via Palladium-Catalyzed Aryl Ligation

Jeffrey D. Winkler,* Barry M. Twenter, and Thomas Gendrineau

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

Abstract

A method for the “ligation” of two aromatic rings has been achieved via synthesis of functionalized phenazines by double Buchwald-Hartwig amination of a variety of substituted bromoanilines, followed by in situ oxidation.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1355 - 1361
Published online: 16th August, 2011
DOI: 10.3987/COM-11-S(P)77
Deprotection of 3,4-Dimethoxybenzyl (3,4DMB) Group on γ-Lactam Nitrogen Using Phenyliodine(III) Bis(trifluoroacetate) (PIFA): Application to Isoindolinone Compounds

Kazuhiro Watanabe, Hiroaki Shibata, Yū Imai, and Tadashi Katoh*

*Department of Synthetic Organic Chemistry, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan

Abstract

The secondary amide (γ-lactam) moiety of an isoindolinone ring exhibits high polarity in an unprotected condition. Problems with solubility make handling difficult; therefore, introduction of a protective group is necessary. We discovered that the 3,4-dimethoxybenzyl (3,4DMB) group is an optimal protective group, and that the 3,4DMB group alone could be deprotected under mild conditions with the use of a hypervalent iodine(III) reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA).

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1363 - 1373
Published online: 26th September, 2011
DOI: 10.3987/COM-11-S(P)87
Diastereoselective Synthesis of (±)-Deethyleburnamonine Using a Catalytic Cyclopropane Ring-Opening / Friedel-Crafts Alkylation Strategy

Dadasaheb V. Patil, Marchello A. Cavitt, and Stefan France*

*School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332-0400, U.S.A.

Abstract

A short, diastereoselective synthesis of (±)-deethyleburnamonine is reported with an overall yield of ~18% over six steps. The key synthetic step involves an indium(III)-catalyzed tandem ring-opening/Friedel-Crafts alkylation of a donor-acceptor-acceptor amino cyclopropane to generate the ABDE portion of the target.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1375 - 1382
Published online: 12th September, 2011
DOI: 10.3987/COM-11-S(P)91
Synthesis of Oxacalix[2]m-terphenyl[2]triazine and Its Functionalizations

Muhammad Moazzam Naseer, De-Xian Wang, and Mei-Xiang Wang*

*Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China

Abstract

Oxacalix[2]m-terphenyl[2]triazine, a macrocyclic host molecule of an expanded cavity, was synthesized from 1,3-(4-hydroxyphenyl)benzene and cyanuric chloride using the fragment coupling strategy. Aromatic nucleophilic substitution reaction of chlorotriazine moieties with di(2-hydroxyethyl)amine and di(2-pyridylmethyl)amine afforded the corresponding upper-rim functionalized oxacalix[2]m-terphenyl[2]triazines in good yields.

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Short Paper | Special issue | Vol 84, No. 2, 2012, pp. 1383 - 1389
Published online: 1st November, 2011
DOI: 10.3987/COM-11-S(P)99
The Synthesis and Antimicrobial Evaluation of Some Spiro-Phthalidyl Benzoxazinones

Caterina Ferraro, István Lengyel, and Ralph Stephani*

*Department of Chemistry, St. John's University, 8000 Utopia Parkway, Jamaica, New York 11439, U.S.A.

Abstract

Five N-substituted spiro-phthalidyl benzoxazinones (5a-e) were prepared from anthranilic acid (1) and the appropriate alkyl or aryl halides (2), followed by condensation of the N-substituted anthranilic acids (3) with symmetrical phthaloyl dichloride (4). These compounds were then evaluated for antimicrobial activity against: E. coli, S. aureus, B. subtilis, P. aeruginosa, S. cerevisiae, and A. nidulans. Compound 5a was active against all the microbes tested, especially the A. nidulans. Compound 5c was active against all the bacteria, except the fungus A. nidulans. The N-benzyl (5b) and N-phenyl (5d) derivatives were not active at all. The N-4-fluorophenyl analog 5e showed activity against S. aureus and B. subtilis.

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55 data found. 31 - 55 listedFirst Previous