HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Special Issue
Keiichiro Fukumoto's Special Issues, Vol. 77, No. 2, 2009
Published online: 22nd September, 2008
■ Pterdines CXX. Synthesis and Properties of Tetrahydropterins Coupled to 1,4-Dihydropyridines
Joachim Rehse and Wolfgang Pfleiderer*
*Department of Chemistry, University of Konstanz, Posttach 55 60, 78434 Konstantz, Germany
Abstract
N2-Isobutyroyl-5,6,7,8-tetrahydropterins (6-10) have been coupled with nicotinic acid to form the N5-nicotinoyl derivatives 11-15. Quaternization at the pyridine moiety led to 19-31 which can be reduced to the corresponding N-substituted 1,4-dihydropyridine dertivatives 35-39. Partial deacylation of the isobutyroyl group afforded the various types of terahydropterins 16-18, 32-34 and 40-42. The newly synthesized 5,6,7,8-tetrahydropterin derivatives have been characterized by pKa-determinations, UV- and NMR-spectra as well as elemental analyses.
Published online: 2nd October, 2008
■ Nucleophilic Substitution Reaction in Indole Chemistry: 1-Methoxy-6-nitroindole-3-carbaldehyde as a Versatile Building Block for 2,3,6-Trisubstituted Indoles
Koji Yamada, Fumio Yamada, Takei Shiraishi, Saori Tomioka, and Masanori Somei*
*Faculty of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
Abstract
1-Methoxy-6-nitroindole-3-carbaldehyde is proved to be a versatile electrophile and reacts regioselectively at the 2-position with various types of nucleophiles providing 2,3,6-trisubstituted indole derivatives. The reaction is applicable for the preparation of a novel pyrimido[1,2-a]indole derivative.
Published online: 11th September, 2008
■ A Convenient Synthetic Method for Fluorine-containing 4-Alkoxy-dihydrobenzo[b][1,4]diazepinols and 3H-Benzo[b][1,4]diazepines by the Reaction of β-Trifluoroacetylketene Acetals with 1,2-Phenylenediamines
Norio Ota, Etsuji Okada,* Naoya Terai, Tomomi Miyamura, Dai Shibata, and Tsuneaki Sakai
*Department of Chemical Science and Engineering, Faculty of Engineering, Kobe University, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
Abstract
β-Trifluoroacetylketene dialkyl acetals (3 and 5) reacted easily with various 1,2-phenylenediamines to give novel 4-alkoxy-2-trifluoromethyl-2,3- dihydro-1H-benzo[b][1,4]diazepinols (6 and 8) in moderate to high yields. Dehydration of 6 and 8 proceeded thermally under reduced pressure to afford the corresponding fluorine-containing 3H-benzo[b][1,4]diazepines (7 and 9).
Published online: 29th September, 2008
■ Selective Lithiation of 4- and 5-Halophthalans
Daniel García, Francisco Foubelo,* and Miguel Yus*
*Department of Organic Chemistry, Faculty of Sciences and Institute of Organic Synthesis (ISO), University of Alicante, P.O. Box 99, 03080 Alicante, Spain
Abstract
The reaction of 4- and 5-halophthalans 5 with lithium and a catalytic amount of DTBB at -78 °C leads to the formation of the corresponding functionalized organolithium intermediates 6 and 11, which by reaction with carbonyl compounds give, after hydrolysis, the expected substituted phthalans 8 and 13, respectively. When after reaction with the carbonyl compound the system is allowed to react at 0 °C, a second lithiation occur: A reductive opening of the heterocycle takes place with some regioselectivity leading to new organolithium intermediates 9 and 14/15 that by reaction with electrophiles lead, after hydrolysis, to polyfunctionalized molecules 10 and 16/17, respectively.
Published online: 6th October, 2008
■ Heterogeneous Lewis Acid Catalysis with Self-organized Polymeric Rare Earth Arylsulfonates under Solvent-free Conditions
Hiroshi Furuno,* Shuichi Ishida, Shoko Suzuki, Tetsuji Hayano, Satoaki Onitsuka, and Junji Inanaga*
*Synthetic Methodology and Catalysis, Institute for Materials Chemistry and Engineering (IMCE), Kyushu University
Abstract
Polymeric rare earth arylsulfonates, easily prepared from rare earth triisopropoxides and biphenyl-4,4’-disulfonic acid (BPDSA) or 1,3,5-triphenylbenzene trisulfonic acid (TPTSA) in a self-organization manner, were found to work as an efficient heterogeneous Lewis acid catalyst for the hetero-Diels-Alder reaction of aldehydes with the Danishefsky‘s diene and the ring-opening reaction of epoxides with amines under solvent-free conditions. The catalysts could be quantitatively recovered and reused many times without decreasing their activities.
Published online: 2nd October, 2008
■ Synthesis and Properties of Novel Biologically Interesting Polycyclic 1,3,4-Oxadiazoles Containing Acridine/Acridone Moieties
Zdenka Fröhlichová, Jana Tomascikova, Ján Imrich,* Pavol Kristian, Ivan Danihel, Stanislav Böhm, Danica Sabolová, Mária Kozurková, and Karel D. Klika
*Department of Organic Chemistry, P. J. Safárik University, Moyzesova 11, SK-041 67 Kosice, The Slovak Republic
Abstract
A series of polycyclic 1,3,4-oxadiazoles bearing acridine and acridone pharmacophores were synthesized as potential noncovalent DNA-binding and antitumor agents. The synthesis of oxadiazoles with acridone moiety was performed exploring oxidative cyclization of corresponding aldimines via bromine and the acridine derivatives by cyclization of acylthiosemicarbazides with mercuric oxide. The spectroscopic properties of the compounds in the case of acridonoxadiazoles showed an efficient binding activity to DNA (K = 5.3-9.2 x 104 M-1), whereas the acridine analogues are suitable as biomarkers. The structure of compounds were characterized by spectral methods (UV-vis, IR, 1H, 13C, and 2D NMR) and quantum-chemical calculations (DFT, ZINDO).
Published online: 29th September, 2008
■ Ether Formation in the Hydrogenolysis of Hydroxymethylfurfural over Palladium Catalysts in Alcoholic Solution
Gerard C. A. Luijkx, Nina P. M. Huck, Gred van Rantwijk, Leendert Maat,* and Herman van Bekkum*
*Faculty of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands
Abstract
5-Hydroxymethylfurfural, a product from renewable feedstock, was subjected to hydrogenolysis over palladium catalysts in 1-propanol aiming at the synthesis of 2,5-dimethylfuran, a potential transportation fuel enhancer. Intermediates are 5-hydroxymethyl-2-(propyloxymethyl)furan, formed with high selectivity, and 5-methyl-2-(propyloxymethyl)furan. Acetals are assumed to be initially formed. Acetalisation and hydrogenolysis are catalysed by traces of a Brønsted acid. Important variables are the palladium support and the solvent. In 2-propanol also ether formation takes place. In 1,4-dioxane mainly 2,5-bis(hydroxymethyl)furan is formed, in water ring opening becomes a major reaction. The formation of some side-products is discussed.
Published online: 16th October, 2008
■ Efficient Synthesis of [2]Rotaxanes Based on Sequential Acetylene-Dicobalt Hexacarbonyl Complexation and Stopper Modification
Yuji Tokunaga,* Norihiro Ohiwa, Go Ohta, Yuji Yamauchi, Tatsuhiro Goda, Nobuhiko Kawai, Takumichi Sugihara, Youji Shimomura, and Tomonori Hoshi
*Department of Materials Science and Engineering, Faculty of Engineering, Fukui University, Bunkyo, Fukui 910-8507, Japan
Abstract
This paper describes an efficient end-capping method for the preparation of [2]rotaxanes, using acetylene–dicobalt hexacarbonyl complexation and subsequent transformation of the complexes into a series of vinylsilanes though hydrosilylation.
Published online: 27th October, 2008
■ Preparation of 1,4-Bis[2-{2-(1-methyl-1H-imidazol-5-yl)ethynyl}-3-thienyl]benzene and Related Compounds
Kozo Toyota,* Kazuyuki Okada, Hiroshi Katsuta, Yasutomo Tsuji, and Noboru Morita
*Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
Abstract
1,4-Bis[2-{2-(1-methyl-1H-imidazol-5-yl)ethynyl}-3-thienyl]benzene, 1,4-bis[2-(2-ferrocenylethynyl)-3-thienyl]benzene, and some related compounds were prepared and their UV-visible spectra were studied.
Published online: 9th October, 2008
■ A New Chiral Synthesis of Wieland-Miescher Ketone Catalyzed by a Combination of (S)-N-Benzyl-N-(2-pyrrolidinylmethyl)amine Derivative and Brønsted Acid
Yuichi Akahane, Kohei Inomata,* and Yasuyuki Endo
*Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
Abstract
New or known N-benzyl-N-(2-pyrrolidinylmethyl)amine derivatives bearing a variety of substituents on the aromatic ring were easily prepared from N-Boc-proline or N-Boc-prolinol. The enantioselectivity of the intramolecular asymmetric aldol reaction mediated by a combination of the amine derivative and Brønsted acid to prepare Wieland-Miescher ketone was examined in detail. During the examination, remarkable substitutional effects on the aromatic ring were observed. Development of a catalytic version of the reaction was successfully achieved by the use of N-[(9-anthracenyl)methyl]-N-(2-pyrrolidinylmethyl)amine in the presence of dichloroacetic acid.
Published online: 2nd October, 2008
■ Preparation of Azulene Substituted Pyrazine and Quinoxaline Derivatives
Nozomi Furuta, Takuo Mizutani, Akira Ohta, and Kunihide Fujimori*
*Department of Chemistry, Faculty of Science, Shinshu University, Asahi, Matsumoto 390-8621, Japan
Abstract
2,3-Di(2-azulenyl)pyrazines and -quinoxalines were obtained by the reaction of di(2-azulenyl)ethanedione with diamines. Cyclodehydrogenation reaction of the pyrazine and quinoxaline derivatives with manganese dioxide afforded the corresponding azulene-fused quinoxaline and phenazine derivatives, respectively.
Published online: 29th September, 2008
■ Mild and Efficient Deprotection of Acetal-Type Protecting Groups of Hydroxyl Functions by Triethylsilyl Triflate—2,4,6-Collidine Combination
Hiromichi Fujioaka,* Ozora Kubo, Kazuhisa Okamoto, Kento Senami, Takashi Okitsu, Takkuya Ohnaka, Yoshinari Sawama, and Yasuyuki Kita*
*Graduate School of Pharmaceutical Science, Osaka University, 1-6 Yamadaoka, Suita, Osaka 560-0871, Japan
Abstract
Deprotection of acetal-type protecting groups of hydroxyl functions has been studied in detail. The treatment of alcohol derivatives protected by acetal-type protecting groups with TESOTf—2,4,6-collidine followed by H2O-treatment produces the corresponding hydroxyl compounds in good yields. The characteristic features of the method are very mild and chemoselective, and acid-labile functional groups can tolerate these conditions.
Published online: 6th October, 2008
■ A General Method for the Synthesis of N-Unsubstituted 3,4-Diarylpyrrole-2,5-dicarboxylates
Tsutomu Fukuda, Yukie Hayashida, and Masatomo Iwao*
*Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan
Abstract
A general method for the synthesis of N-unsubstituted 3,4-diarylpyrrole-2,5-dicarboxylates (3) has been developed. The key reactions involved are the Hinsberg-type synthesis of dimethyl N-benzyl-3,4-dihydroxypyrrole-2,5-dicarboxylate (6) followed by palladium-catalyzed Suzuki-Miyaura coupling of its bis-triflate derivative (7). The N-benzyl protecting group of the resulting 3,4-diarylpyrrole-2,5-dicarboxylates (8) is cleanly removed under hydrogenolytic or solvolytic conditions.
Published online: 9th October, 2008
■ Synthesis of Annulated 1,4-Dioxanes and Perhydro-1,4-oxazines by Domino-Wacker-Carbonylation and Domino-Wacker-Mizoroki-Heck Reactions
Lutz F. Tietze,* Arne Heins, Mohammad Soleiman-Beigi, and Christian Raith
*Institute of Organic and Biomolecular Chemistry, Georg-August-University, Tammannstr. 2, D-37077 Göttingen, Germany
Abstract
Palladium(II)-catalyzed domino reactions for the formation of 1,4-dioxanes and perhydro-1,4-oxazines starting from hydroxy alkenes are described. The domino-Wacker-carbonylation comprises a Wacker oxidation, subsequent CO-insertion and a nucleophilic substitution of the intermediately formed Pd-species. The domino-Wacker-Mizoroki-Heck reaction proceeds via a Wacker oxidation, subsequent insertion into the olefinic π-bond of α,β-unsaturated carbonyl compounds and β-hydride elimination.
Published online: 22nd September, 2008
■ Benzimidazoline-Dimethoxypyrene. An Effective Promoter System for Photoinduced Electron Transfer Promoted Reductive Transformations of Organic Compounds
Eietsu Hasegawa,* Harumi Hirose, Kosuke Sasaki, Shinya Takizawa, Takayuki Seida, and Naoki Chiba
*Department of Chemistry, Faculty of Sciences, Niigata University, Ikarasi 2-8050, Niigata 950-2181, Japan
Abstract
2-(p-Methoxyphenyl)-1,3-dimethylbenzimidazoline (ADMBI) and 2-(o-hydroxyphenyl)-1,3-dimethylbenzimidazoline (HPDMBI) are used as reducing reagents in 1,8-dimethoxypyrene (1,8-DMP) sensitized, photoinduced electron transfer (PET) reactions. This system was effectively used for PET induced, reductive transformations of various organic substrates, including α,β-epoxy ketones, the olefin tethered 2-bromomethyl-1-tetralone, and o-allyloxy-iodobenzene, as well as for the deprotection reactions of dodecyl-2-benzoylbenzoate and N-sulfonylindole. The results of studies show that 1,8-DMP is a more effective sensitizer than the previously used 9-methylcarbazole for deprotection of N-methyl-4-picolinium ester.
Published online: 22nd September, 2008
■ Dehalogenation and Barbier-Type Hydroxyalkylation of π-Deficient Haloheterocycles Using Indium
Eri Fukuda, Yukiko Takahashi, Natsumi Hirasawa, Osamu Sugimoto,* and Ken-ichi Tanji
*Laboratory of Organic Chemistry, School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan
Abstract
The reaction of π-deficient haloheterocycles with indium metal in water gave corresponding dehalogenated heterocycles. The use of diluted hydrochloric acid instead of water accelerated the reductive reactivity of indium metal. Furthermore, Barbier-type additions proceeded by reactions of α-iodoheterocycles with indium in the presence of pivalaldehyde.
Published online: 18th September, 2008
■ Synthesis and Structures of Alkynylchlorocyclotriphosphazenes and Their Cluster-forming Reactions with Octacarbonyldicobalt
Takashi Komuro, Kenichi Mori, and Hiromi Tobita*
*Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
Abstract
Cyclotriphosphazenes having p-tolylethynyl and chloro substituents N3P3{C≡C(p-Tol)}nCl6-n (1a: n = 2, 1b: n = 4; p-Tol = p-tolyl) were synthesized by the reaction of hexachlorocyclotriphosphazene (NPCl2)3 with 2 equiv of LiC≡C(p-Tol) in THF. 1a and 1b were characterized by spectroscopic methods and elemental analyses. The reactions of 1a and 1b with octacarbonyldicobalt Co2(CO)8 produced cobalt clusters containing tetrahedral C2Co2(CO)6(p-Tol) cluster units; namely, tetranuclear cluster N3P3{C2Co2(CO)6(p-Tol)}2Cl4 (2) and hexanuclear cluster N3P3{C2Co2(CO)6(p-Tol)}3{C≡C(p-Tol)}Cl2 (3). Crystal structures of 1a and 2 were determined by X-ray crystallography.
Published online: 29th September, 2008
■ Synthesis of Marine Oxylipin Agardhilactone and its Analogues: A Structural Revision
Hiromi Miyaoka,* Yoshinori Hara, Ikuo Shinohara, Takao Kurokawa, Etsuko Kawashima, and Yasuji Yamada
*School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
Abstract
Synthesis of four analogues of the marine oxylipin agardhilactone was carried out. The relative configuration of agardhilactone was determined by comparison with agardhilactone acetate and four analogues. Furthermore, synthesis of agardhilactone was achieved. The absolute configuration of agardhilactone was successfully determined by this synthesis.
Published online: 6th October, 2008
■ Synthesis and Properties of 2’-Deoxy-trans-3’,4’-BNA with S-Type Sugar Puckering
Tetsuya Kodama, Kensaku Sugaya, Yasuki Harada, Yasunori Mitsuoka, Takeshi Imanishi, and Satoshi Obika*
*Graduate School of Pharmaceutical Science, Osaka University, 1-6 Yamadaoka, Suita, Osaka 560-0871, Japan
Abstract
2’-Deoxy-trans-3’,4’-BNA monomer, which was previous synthesized as part of a study on bridged nucleic acids with S-type sugar puckering, was introduced into an oligodeoxynucleotide using phosphoramidite chemistry, and the hybridization ability of the 2’-deoxy-trans-3’,4’-BNA-modified oligonucleotide with complementary DNA and RNA strands was evaluated. The 2’-deoxy-trans-3’,4’-BNA-modified oligonucleotide showed greatly improved hybridization ability compared to its 2’-methoxy congener (2’-methoxy-trans-3’,4’-BNA), which suggested that the sugar-restriction of nucleic acids to S-type conformation with appropriate design may be useful for development of DNA mimics.
Published online: 25th September, 2008
■ Total Synthesis of (±)-Morphine
Kenji Uchida, Satoshi Yokoshima, Toshiyuki Kan, and Tohru Fukuyama*
*Laboratory of Synthetic Organic & Medicinal Chemistry, Schol of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan
Abstract
The morphinan skeleton was effectively synthesized by an intramolecular Mannich-type reaction. Further transformation led to the total synthesis of morphine.
Published online: 2nd October, 2008
■ Synthesis of Mono-, Di- and Tribenzoporphyrins from their Soluble Precursors
Tetsuo Okujima,* Yusuke Hashimoto, Guangnan Jin, Hiroko Yamada, and Noboru Ono
*Department of Chemistry and Biology, Graduate School or Science and Engineering, Ehime University, Matsuyama 790-8577, Japan
Abstract
Soluble precursors of β-, meso-unsubstituted mono-, di- and tribenzoporphyrins were prepared by the reaction of dimethylbicyclo[2.2.2]octadiene-fused pyrrole with appropriate β-free pyrroles. The retro Diels-Alder reaction of these precursors afforded the corresponding benzoporphyrins in quantitative yields.
Published online: 31st October, 2008
■ Preparation and Synthetic Applications of N-(α,β-Unsaturated Acyl)-α-amino Acid Derivatives
Alan R. Katritzky,* Reena Gyanda, Nabin K. Meher, and Yuming Song
*Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, U.S.A.
Abstract
N-(α,β-Unsaturated acyl)-α-amino acids, amides and esters are structural motifs of many biologically active natural products. An alternate and advantageous approach for the synthesis of N-(α,β-unsaturated acyl)-α-amino acid derivatives is developed via acylation of unprotected α-amino acids with stable crystalline N-(α,β-unsaturated acyl)benzotriazole. The proposed methodology provides a new synthesis for compound (9) which is a precursor to a novel cytotoxic agent.
Published online: 18th November, 2008
■ Effect of Fused Benzene Ring on Rotational Barriers of 2,2’-Bifuran, 2-Phenylfuran, Biphenyl, and Their Benzo Analogues
Naoto Hayashi,* Yoko Saito, and Hiroyuki Higuchi*
*Department of Chemistry, Faculty of Science, Toyama University, Gofuku 3190, Toyama 930, Japan
Abstract
Molecular orbital (MO) calculations of torsional potentials of 2,2’-bifuran (F-F), 2-(2-furyl)benzofuran (F-BF), 2-phenylfuran (Ph-F), 2-(2-naphthyl)furan (Naph-F), 2-phenylbenzofuran (Ph-BF), biphenyl (Ph-Ph), 2-phenylnaphthalene (Ph-Naph), 2-phenylbenzo[1,2-b:4,5-b’]difuran (Ph-BDF), and 2-phenylbenzo[1,2-b:5,4-b’]difuran (Ph-BDF’) by using HF/6-31G** and B3LYP/6-31G** methods have revealed that the rotational barriers are increased by 0.4-0.9 kcal/mol by replacement of the aryl moiety on the furan ring (furyl group of F-F and phenyl of Ph-F) with its benzo analogue. In contrast, increase of the rotational barriers is slight when the aryl moiety on the benzene ring (phenyl groups of Ph-F and Ph-Ph) is replaced with its benzo analogue and more extended π moiety.
Published online: 11th November, 2008
■ Rhodium-Catalyzed Conjugate Addition of Sb-Aryl-1,5-azastibocines to α,β-Unsaturated Carbonyl Compounds
Naoki Kakusawa, Shuji Yasuike, and Jyoji Kurita*
*Faculty of Pharmaceutical Sciences, Hokuriku University, 3-Ho, Kanagawa machi, Kanazawa 920-1181, Japan
Abstract
Rhodium-catalyzed conjugate addition of Sb-aryl-1,5-azastibocines to α,β-unsaturated carbonyl compounds is described．The rhodium-catalyzed reaction was carried out in aqueous N-methy-2-pyrrolidinone (NMP) to give 1,4-conjugate adduct exclusively, while the palladium catalyzed reaction gave only Heck-type adduct. The 1,4-addition of various aryl groups such as substituted benzenes and thiophenes was achieved with various enones and enoate.
Published online: 6th October, 2008
■ Synthesis of Isochromanes and Isothiochromanes Bearing Fluorinated One-Carbon Units via Intramolecular Cyclizations of ortho-Substituted α-(Trifluoromethyl)styrenes
Junji Ichikawa,* Masahiro Ikeda, and Masahiro Hattori
*Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba-shi, Ibaraki 305-0006, Japan
Abstract
α-(Trifluoromethyl)styrenes bearing a nucleophilic oxygen or sulfur atom tethered by a methylene or methyne unit at the ortho carbon were prepared by the coupling reaction of 2-bromo-3,3,3-trifluoropropene with aryl iodides via (3,3,3-trifluoroprop-1-en-2-yl)boronic acid. The styrenes thus obtained readily undergo an intramolecular nucleophilic addition or substitution (SN2’-type) of the oxygen and sulfur under basic conditions, leading to 4-trifluoromethyl- or 4-difluoromethylene-substituted isochromanes and isothiochromanes, respectively.
Published online: 16th October, 2008
■ Stereoselective β-D-Psicofuranosylation and Synthesis of β-D-Psicofuranosylceramide
Jun'ichi Uenishi* and Atsushi Ueda
*Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan
Abstract
Psicofuranosylations of alcohols and phenol 3a-e with benzyl D-psicosyl phthalate 2 occurred on the β-face to give β-D-psicoside 4a-e in excellent yields. The reaction of ceramide 5 with 2 and deprotections of acetonide and three benzoates of the resulting glycoside afforded β-D-psicosylceramide 1.
Published online: 28th October, 2008
■ New [11C]Phosgene Based Synthesis of [11C]Pyrimidines for Positron Emission Tomography
Koh-ichi Seki,* Ken-ichi Nishijima, Kimihito Sanoki, Yuji Kuge, Masayuki Takahashi, Hiromichi Akizawa, Nagara Tamaki, Leonard I. Wiebe, and Kazue Ohkura*
*Central Institute of Radio Isotope Science, Hokkaido University, Kita 15 Nishi 7, Kita-ku, Sapporo, Hokkaido 060-0815, Japan
Abstract
Thymine, 5-FU, and uracil were successfully synthesized through a procedure involving a cyclocondensation of triphosgene with newly developed α-substituted β-aminoacrylamides intermediates (1a, X = Me; 1b, X = F; 1c, X = H). The radioligands [2-11C]thymine and [2-11C]5-fluorouracil were synthesized in high radiochemical yields in 16-17 minutes from the end of bombardment by applying the cyclocondensation method with [11C]COCl2.
Published online: 23rd October, 2008
■ Reactivity and Efficient Recycling of a Chiral Pd-BINAP Catalyst for Catalytic Asymmetric Diels-Alder Reaction in Ionic Liquid
Yasuhiro Nishiuchi, Hiroto Nakano,* Yuta Araki, Rina Sato, Reiko Fujita, Koji Uwai, and Mitsuhiro Takeshita*
*Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
Abstract
Chiral cationic palladium-BINAP catalyst in ionic liquid showed an excellent asymmetric catalytic activity in the Diels-Alder reactions using several dienes and the catalyst was easily recycled 7 times with good chemical yield and excellent enantioselectivity (50-60%, 94-98% ee).
Published online: 22nd September, 2008
■ Tandem Metathesis Reactions Cascade Ring-Opening Metathesis (ROM)-Ring-Closing Metathesis (RCM)-Cross Metathesis Dimerization (CMD) in 7-Oxabicyclo[2.2.1]hept-5-one (7-Oxanorbornene) Derivatives
Ana Aljarilla and Joaquín Plumet*
*Department of Organic Chemistry, Faculty of Chemistry, University of Complutense, 28040-Madrid, Spain
Abstract
The domino metathesis sequence ROM-RCM-CMD achieved on conveniently substituted 7-oxabicyclo[2.2.1]hept-5-ene (7-oxanorbornene) derivatives is reported. Experimental conditions in order to carry out this tandem metathetical sequence in a chemoselective fashion is also established.
Published online: 18th September, 2008
■ Quinoline Derivatives by Cyclocondensation of N-(2-Bromophenylmethylphenyl)benzenesulfonamide with Enol Ethers and Enamines
Giuseppe Cremonesi, Piero Dalla Croce,* Francesco Fontana, and Concetta La Rosa
*Department of Organic and Industrial Chemistry, C.N.R. - I.S.T.M., University of Milano, Via Venezian 21, I-20133 Milano, Italy
Abstract
The reaction of N-(2-bromophenylmethylphenyl)benzenesulfonamide (1) with electron rich alkenes (enol ethers (2), (3) and enamines (4)) gives quinoline derivatives 5 and ring fused quinoline 6, 7 whose structures were assigned on the basis of analytical and spectroscopic data. The chemical behavior of adducts 5 and 7 is reported.