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
Steven M. Weinreb's Special Issues, Vol. 70, No. 1, 2006
Published online: 20th June, 2006
■ Strecker Reactions of Chiral N-Acylhydrazones
Hui Ding and Gregory K. Friestad*
*415 Chemistry Building, Department of Chemistry, University of Iowa, 320 North Madison Street, Iowa City, Iowa 52242, U.S.A.
Abstract
Development of a method for addition of trimethylsilyl cyanide to chiral oxazolidinone-derived N-acylhydrazones is described. The diastereoselectivity was found to be highly dependent on the substituent of the oxazolidinone moiety; 4-phenyl-2-oxazolidinone achieved much higher stereocontrol than four other oxazolidinones screened. The reaction gives modest selectivity with aliphatic hydrazones and excellent selectivity with hydrazones prepared from aromatic aldehydes.
Published online: 14th July, 2006
■ Direct Conversion of Substituted Pyrrole-2-carboxylic Acid Methyl Esters to Their 2-Carbonitrile Analogues
Xun Li,* Michael Reuman, and Ronald K. Russell
*US Resarch & Early Development, Johnson & Johnson Pharmaceutical Research & Development, L. L. C., 1000 Route 202, Rartan, New Jersey 08869, U.S.A.
Abstract
Small to large quantity (1-136 g) of substituted pyrrole-2-carbonitrles were reproducibly prepared from their corresponding 2-carboxylic acid methyl esters in one step with 53-61% yield and high chemical purity (>97%), with using dimethylaluminum amide [(CH3)2AlNH2] that was freshly generated by treating anhydrous ammonia (NH3) and trimethylaluminum [(CH3)3Al] at -40 °C in chlorobenzene, a modified Weinreb’s method.
Published online: 11th July, 2006
■ Cycloaddition Reactions of 1-Aza- and 1,3-Diazaazulenium 1-Methylides
Hiroyuki Fujii,* Izumi Kawano, Kaoru Iwafuji, Yoshiyuki Sawae, Kentaro Nagamatsu, and Noritaka Abe*
*Department of Chemistry, Faculty of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan
Abstract
2-Chloro-, 2-methoxy-, and 2-amino-1-azaazulenium 1-methylides and 1,3-diazaazulenium 1-methylide were generated by the treatment of the corresponding 1-trimethylsilylmethyl-1-azaazulenium triflates and 1-trimethylsilylmethyl-1,3-diazaazulenium triflate with CsF; the triflates were prepared from the corresponding 1-azaazulenes and 1,3-diazaazulene with trimethylsilylmethyl triflate. The 1,3-dipolar cycloadditions of the 2-chloro-1-azazaazulenium 1-methylide, prepared in situ, with acetylenic esters gave 2a-azabenz[cd]azulene derivatives and 3a-azacyclopenta[a]naphthalene derivatives as major products, whereas 2-piperizino-1-azaazulenium 1-methylide underwent extended dipolar cycloaddition with acetylenic esters and afforded 9b-azacyclopent[a]azulene derivatives as major products.
Published online: 29th August, 2006
■ A De Novo Asymmetric Approach to Achiral Deoxy-Melodorinol Analogues
Md. Moinuddin Ahmed, Novruz Akhmedov, Hu Cui, Dirk Friedrich, and George A. O’Doherty*
*Department of Chemistry, West Virginia University, Morgantown, WV 26506-6045, U.S.A.
Abstract
A short and highly efficient route to deoxy-Melodorinol analogues has been developed. The key to the overall transformation is the use of an enantioselective Sharpless asymmetric dihydroxylation of an (Z,E)-dienoate to control the regioselectivity of the dihydroxylation reaction and a Mitsunobu elimination reaction to control the E-stereochemistry of the γ,δ-double bond. The highly efficient synthesis stereoselectively prepared four analogues in 3 steps from 4-substituted crotonaldehydes.
Published online: 29th August, 2006
■ Pyran-2-ones as Synthons for Pyridazine-3-carboxylic Derivatives. Oxidation of Nitrogen-Rich Compounds
Franc Pozgan, Stanislav Kafka, Slovenko Polanc, and Marijan Kočevar*
*Department of Organic Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, P.O. Box 537, SI-1000 Ljubljana, Slovenia
Abstract
The reaction of 6-(pyridin-2-yl)-2H-pyran-2-one (1) with hydrazine hydrate toward pyridazine derivatives was investigated. To elucidate the reaction pathway, an intermediary-formed α,β-dihydrazonohydrazide derivative (3) was successfully isolated. Oxidations of the above compounds as well as of other pyridazine derivatives containing a carbohydrazido group, using ammonium cerium(IV) nitrate (CAN), thallium(III) nitrate trihydrate (TTN), or copper(II) acetate hydrate (CuDA), are also presented.
Published online: 22nd September, 2006
■ The Concise and Versatile Synthesis of Epi-malbrancheamide and Structurally Related Analogs
Meriah W. N. Valente and Robert M. Williams*
*Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, U.S.A.
Abstract
The synthesis of C-19-epi-malbrancheamide and several structurally related analogs is reported.
Published online: 5th September, 2006
■ Selective 1,2- vs 1,4-Addition of N-Arylphosphazenes to β,γ-Unsaturated α-Ketoesters. Synthesis of Quinolinecarboxylates
Francisco Palacios,* Javier Vicario, Jesús M. de los Santos, and Domitila Aparicio
*Department of Organic Chemistry I, Faculty of Pharmacy, University of The Basque Country, P.O. Box 450, 01080 Vitoria, Spain
Abstract
Selective conjugate reaction (1,4 addition) of N-arylphosphazenes derived from triphenylphosphine to α,β-unsaturated carbonyl compounds yielded 2-quinolinecarboxylates. However, when more reactive phosphazene species derived from trimethylphosphine were used, selective reaction with the carbonyl carbon (1,2-addition) occurred and N-aryl 1-azadienes were obtained. Thermal 6π-azaelectrocyclization of these 1-azadienes afforded 4-quinolinecarboxylates.
Published online: 12th September, 2006
■ Dediastereomerization of Dibenzylbutanolides by Plant Cell Culture
Masumi Takemoto,* Yuki Matsuoka, Kiyoshi Tanaka, and James Peter Kutney
*Schol of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan
Abstract
When a mixture of two diastereomers (4R*-3) and (4S*-3) was subjected to plant cell cultures, hydrolysis of acetate and dediastereomerization took place to give a single diastereomer (4R*-1) with 100% diastereomeric excess and 0% enantiomeric excess.
Published online: 15th September, 2006
■ Synthesis of (+)-Myrtopsine, (+)-7,8-Dimethoxymyrtopsine, and Related 2,3-Dihydro-3-hydroxy-2-(1-hydroxy-1-methylethyl)benzofuran Natural Products
Barry B. Snider* and Xiaoxing Wu
*Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02254-9110, U.S.A.
Abstract
The first syntheses of myrtopsine (8t) and 7,8-dimethoxymyrtopsine (9t) have been carried out by halogen-metal exchange of 3-iodo-4-methoxyquinolin-2(1H)-ones (15) and (21) with i PrMgCl followed by addition of 3,3-dimethyloxirane-2-carboxaldehyde. A two-step sequence leads selectively to trans-2,3-dihydro-3-hydroxy-2-(1-hydroxy-1-methylethyl)benzofurans (7t), (8t), (9t), (28), and (32) by conversion of a 2-iodophenol or a 3-iodo-4-methoxyquinolin-2(1H)-one to an aryl Grignard reagent and addition of 3-methyl-2-butenal, followed by threo selective epoxidation of the resulting allylic alcohol and cyclization with inversion.
Published online: 15th September, 2006
■ Two Convergent Approaches to the Synthesis of 1α,25-Dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (ED-71) by the Lythgoe and the Trost Coupling Reactions
Junji Maeyama, Hiroko Hiyamizu, Keisuke Takahashi, Jun Ishihara, Susumi Hatakeyama, and Noboru Kubodera*
*Chugai Pharmaceutical Co., Ltd., 2-1-1, Nihonbashi-Muromachi, Chuo-ku, Tokyo 103-8324, Japan
Abstract
Two convergent syntheses of 1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (ED-71) by the Lythgoe coupling reaction between the A-ring phosphine oxide and the C/D-ring ketone and the Trost coupling reaction between the A-ring ene-yne and the C/D-ring bromomethylene are described.
Published online: 7th November, 2006
■ Synthesis of 2,3-Dihydrobenzo[1,4]dioxins and -oxazins via a Domino Wacker-Heck Reaction
Lutz G. Tietze,* Kristina F. Wilckens, Sinem Yilmaz, Florian Stecker, and Julia Zinngrebe
*Institute of Organic and Biomolecular Chemistry, Georg-August-University, Tammannstr. 2, D-37077 Göttingen, Germany
Abstract
An efficient and operationally simple domino Wacker-Heck reaction of allylic phenols and α,β-unsaturated ketones as well as esters in the presence of catalytic amounts of Pd(TFA)2 and an oxidant for the synthesis of 2,3-dihydrobenzo[1,4]dioxins and 2,3-dihydrobenzo[1,4]oxazins is described. The necessary substrates are prepared by monoallylation of catechol derivatives and ortho-aminophenol.
Published online: 10th October, 2006
■ A Chiral Pool Approach toward the Synthesis of Thalidomide Metabolites
Frederick A. Luzzio,* Damien Y. Duveau, and William D. Figg
*Department of Chemistry, University of Louisville, 2320 South Brook Streeet, Louisville, KY 40292, U.S.A.
Abstract
A synthetic strategy toward the glutarimide-derived metabolite of thalidomide, 5’-hydroxythalidomide (5’-OH THD, 2) was developed which utilizes aspartic acid as a “chiral pool”-type starting material. The synthesis incorporates a Henry reaction as the key carbon-carbon bond-forming step followed by a tandem reduction-cyclization of the intermediate nitroalcohol in forming the heterocyclic core of 5’-OH THD
Published online: 17th October, 2006
■ Enantioselective Synthesis of ent-Sedridine and (+)-Coniine via Proline-Catalyzed Mannich Reaction
Kazuhiro Nagata, Kosuke Nishimura, Masashi Yokoya, and Takashi Itoh*
*School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
Abstract
Proline-catalyzed three component Mannich reaction using 5-hydroxypentanal as a substrate was achieved in high enantioselectivity to construct a chiral center at C-2 position of 2-substituted piperidine alkaloids. The method was applied to the total syntheses of ent-sedridine and (+)-coniine.
Published online: 6th October, 2006
■ Dual Fluorescence Spectra of 1-Hydroxyindoles with Various C-C-Nb Side Chains at 3-Position in Methanol
Kunihiro Tokumura,* Akio Hayashi, Kenta Imai, and Masanori Somei*
*Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
Abstract
Almost the same ultraviolet absorption spectra with a broad peak at 292-294 nm and a shoulder peak at 275 nm were observed for methanol solutions of 1-hydroxyindoles with various C-C-Nb side chains at 3-position such as 1-hydroxy-Nb-methoxycarbonyltryptamine (1), Nb-acetyl-1-hydroxytryptophan methyl ester (2), N,N-dimethyl-1-hydroxyindole-3-acetamide (3), and 1-hydroxy-Nb-pivaloyltryptamine (4). Dual fluorescence excitation and emission spectra resulting from 1La→1A and 1Lb→1A fluorescence emissions were observed for these 1-hydroxyindoles (1 - 4). Excitation spectra were found to be dependent on observing wavelength of broad fluorescence emission spectra (λmax = 346-350 nm for 1, 2, and 3; λmax = 366 nm for 4). Dual fluorescence behaviors can be explained by the fact that 1La state locates slight below 1Lb state, and it is supported by time-dependent density functional theory calculations of 1 - 4 in methanol. It is noteworthy that dual fluorescence behaviors are delicately modified by C-C-Nb side chain at 3-position of indole ring.
Published online: 6th October, 2006
■ Synthesis of 6- and 7-(1,2,3-Trihydroxy-1,2-O-isopropylidenepropyl)pteridines and Deoxygenation of Their 3’-Hydroxy Groups
Tadashi Hanaya,* Daisuke Takayama, and Hiroshi Yamamoto
*Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
Treatment of 3,4-O-isopropylidene-L-threo-pentos-2-ulose (7) with 5,6-diamino-1,3-dimethyluracil (8) afforded 1,3-dimethyl-6-[(1R,2S)-1,2,3-trihydroxy-1,2-O-isopropylidenepropyl]lumazine (9a) and its 7-substituted isomer (9b). Deoxygenation of 3’-hydroxy groups of 9a,b was investigated in connection with a practical transformation of neopterin into biopterin.1
Published online: 21st November, 2006
■ Cycloaddition Reactions of Amino-Acid Derived Cross-Conjugated Trienes: Stereoselective Synthesis of Novel Heterocyclic Scaffolds
Branko Mitasev, Bingli Yan, and Kay M. Brummond*
*Department of Chemistry, University of Pittsburgh, Parkman Avenue & University Drive, Pittsburgh, PA 15260, U.S.A.
Abstract
Cross-conjugated trienes obtained via a Rh(I)-catalyzed allenic Alder-ene reaction represent a new class of compounds. The synthesis of heterocyclic compounds containing multiple fused rings was accomplished via sequential Diels-Alder reactions of amino-acid derived cross-conjugated trienes. Newly synthesized imino-oxazolidinone fused trienes were used to control the stereoselectivity in an intermolecular cycloaddition sequence. Additionally, intramolecular cycloaddition of ester tethered tetraene stereoselectively afforded fused tricyclic pyridino-pyranone which was effectively utilized in subsequent cycloaddition reactions.
Published online: 1st December, 2006
■ The Efficient Separation of Lithium Chloride by Acyclic Carrier Molecules
Junko Morita, Shinji Tsuchiya, Misa Ifuku, Makie Kobayashi, Eriko Araki, Zhenxia Zhu, Keiko Takano, and Shojiro Ogawa*
*Center of Environmental Science for Human Life, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
Abstract
A new acyclic carrier molecule (1) (2,9-didodecanoylamino-1,10-phenanthroline) for the separating purpose of lithium chloride was synthesized by a simple, short synthetic route. Carrier (1) exhibited the high selectivity for binding to the Li+ ion, and has enough ability to form a stable complex consisting of one carrier (1) and one Li+ ion. LiCl is separated efficiently from the mixture of various alkali metal chlorides by using liquid membranes containing carrier (1). The transport rate and selectivity by carrier (1) can are changed by the concentration of metal salts and the properties of anion in the source phase. Two different transport mechanisms are proposed for the explanation of this transport result and molecular orbital calculations on two proposed carrier (1)-Li+ complexes provide a possibility of supporting above explanation. The numerical simulation of Li+ transport using the rate equation of a simple model suggests that the transport by carrier (1) is promoted due to the diffusion limited process and this property is similar to other previously reported macrocyclic carrier molecules. These results indicate an important fact that simple, acyclic compounds have enough ability as LiCl carrier, though the complicated macrocycles with small cavity have been known as Li+ ion selective carriers.
Published online: 24th October, 2006
■ Aza-[3+3] Annulations. Part 6. Total Synthesis of Putative (-)-Lepadiformine and (-)-Cylindricine C
Jiashi Wang, Jacob J. Swidorski, Nadiya Sydorenko, Richard P. Hsung,* Heather A. Coverdale, Jennifer M. Kuyava, and Jia Liu
*Department of Chemistry, University of Minnesota, 207 Pleasant Street S. E. Minneapolis, MN 55455-0431, U.S.A.
Abstract
Efforts in achieving an enantioselective total synthesis of (-)-cylindricine C along with the syntheses of putative lepadiformine, epi-lepadiformines, (-)-4-deoxo-cylindricine C, and (-)-2-epi-cylindricine C are described here in details. These syntheses feature a stereoselective intramolecular aza-[3 + 3] annulation as a unified strategy, and specifically, the total synthesis of (-)-cylindricine C was accomplished in 22 steps with a 4.5% overall yield from L-serine. In addition, we developed an interesting halohydrin formation for the construction of the C4-ketone of cylindricines.
Published online: 2nd November, 2006
■ Synthetic Approaches to Polyhydroxy Indolizidines and Related Azabicyclic Scaffolds
Stephen Hanessian,* Eric Therrien, Jayakumar S. Warrier, and Guillaume Charron
*Department of Chemistry, University of Montreal, 2900 Edouard-Montpetit, Montréal, Québec H3C 3J7, Canada
Abstract
Approaches to the synthesis of unnatural polyhydroxylated indolizidines are described. Key reactions involve addition of 2-(trimethylsilyloxy)furan to iminium salts, and ring-closure metathesis as second alternative.
Published online: 2nd November, 2006
■ Synthesis of 1,2,3,4,5,6,7,10-Octahydro-1,5-imino-7,10-dioxo-3-benzazocine-4-carbonitrile Derivative and Evaluation of Antitumor Activity Related to Saframycin and Renieramycin Isoquinolinequinones
Yu-ichi Koizumi, Ken-ichi Inamura, Akinori Kubo, and Naoki Saito*
*Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan
Abstract
3-Benzyl-1,2,3,4,5,6,7,10-octahydro-9-methoxy-8,11-dimethyl-7,10- dioxo-1,5-imino-3-benzazocine-4-carbonitrile (4) as a simple model of saframycin A and renieramycin M is prepared and its cytotoxicity tested against three human cancer cell lines.
Published online: 24th October, 2006
■ Synthesis of 6-Methylindole-4,7-quinone and Anti-tumor Activities of Its Related Indolequinones
Junko Nobuhiro, Miho Hirayama, Tominari Choshi, Keiichi Kamoshita, Sakiko Maruyama, Yoshikazu Sukenaga, Takashi Ishizu, Haruto Fujioka, and Satoshi Hibino*
*Graduate School of Pharmacy and Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan
Abstract
We synthesized 6-methylindole-4,5-quinone (1b) in order to clarify the structure of natural product, 5-methylindole-4,5-quinone (1a) isolated from Drupella fragum. The synthesis features the construction of the indole ring based on an electrocyclic reaction of a 3-alkenyl-2-propargylpyrrole intermediate.
Two synthetic methylindolequinones and their related compounds were examined in human lung cancer cell line NCI-H460 and human breast cancer cell line MDA-MB-231.
Published online: 17th November, 2006
■ Photochemical Synthesis of Polycyclic Pyrimidines through the Acid Catalyzd Cycloaddition of 6-Chloro-1-methyluracil to Methyl Substituted Benzenes
Kazue Ohkura,* Takeshi Yamaguchi, Ken-ichi Nishijima, Yuji Kuge, and Koh-ichi Seki
*Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan
Abstract
UV-irradiation of 6-chloro-1-methyluracil with benzene in the presence of TFA resulted in 1,2-cycloaddition and susequent elimination of HCl gave a cyclooctapyrimidine-2,4-dione. Similar acid catalyzed photoreaction with substituted benzenes bearing two or three methyl groups afforded the corresponding cyclooctapyrimidines and two novel pentacyclic compounds, 9,11-diazapentacyclo[6.4.0.01,3.02,5.04,8]dodecanes and 9.11-Å@diazapentacyclo[6.4.0.01,3.02,6.04,8]dodcanes, in fair yields.
Published online: 24th November, 2006
■ Synthesis of a Stable Pyridyl Boronate and Its Reaction with Aryl and Heteroaryl Halides
Steven J. Durrant,* Joanne L. Pinder,* Jean-Damien Charrier, Juan-Miguel Jimenez, Guy Brenchley, Philip N. Collier, David Kay, Andrew Miller, Françoise Pierard, Sharn Ramaya, Shazia Sadiq, and Heather C. Twin
*Vertex Pharmaceuticals Limited, 88 Milton Park, Abingdon, Oxfordshire, OX14 4RY, U.K.
Abstract
The synthesis and reaction of a versatile 5-pyridyl boronate is described. This intermediate can be used to synthesize a range of biologically interesting 2-(1H)-pyridones.
Published online: 21st November, 2006
■ Alkylation of 2-Butyl-4,4-dimethyl-4H-benzo[d][1,3]oxathiien-1,1-dioxide, a New Class of Acyl Anion Equivalents as an Alternative to Dithianes
Robert K. Boeckman, Jr.,* Susan M. Hanson, and Jeremy A. Cody
*Department of Chemistry, University of Rochester, University of Rochester, U.S.A.
Abstract
(2-Butyl-4,4-dimethyl-4H-benzo[d][1,3]oxathiine-1,1-dioxide has been found to react with several electrophiles, such as various halides and aldehydes, upon regioselective deprotonation. This method utilizes the sulfone group to form new carbon-carbon bonds while serving as a masked carbonyl. Subsequent hydrolysis of the sulfone provides a facile approach toward many useful synthetic intermediates. This methodology could provide a useful alternative to the use of dithiane groups.
Published online: 20th June, 2006
■ A Facile Construction of the Benz[c,d]indole Framework
Clifford E. Soll and Richard W. Franck*
*Department of Chemistry, Hunter College, City University of New York (CUNY), 695 Park Ave., New York, NY 10021, U.S.A.
Abstract
The Bradsher cycloaddition of isoquinolinium salts has been applied to 5-acetaminoisoquinoline. In 3 simple steps: (i) quaternization of isoquinoline N (ii) cycloaddition with electron-rich dienophile (iii) dehydration, the benz[c,d]indole framework is formed.
Published online: 11th July, 2006
■ Chiral Synthesis of Poison-Frog Alkaloids 251N and 221K
Naoki Toyoooka,* Zhou Dejun, Hideo Nemoto,* H. Martin Garraffo, Thomas F. Spande, and John W. Daly
*Faculty of Pharmaceutical Sciences, Toyama University, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
Abstract
The chiral synthesis of 8-butyl 5-substituted poison-frog alkaloids 251N and 221K has been achieved, and the relative stereochemistry of natural 251N was determined by the present chiral synthesis.
Published online: 12th September, 2006
■ Biaryl Coupling Reactions of 3-Methoxy-N-(2-iodophenyl)-N-methylbenzamide and 3-Methoxycarbonyl-N-(2-iodophenyl)-N-methylbenzamide Using Palladium Reagent
Hiromi Nishioka,* Chie Nagura, Hitoshi Abe, Yasuo Takeuchi, and Takashi Harayama*
*Faculty of Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Okayama 700-8530, Japan
Abstract
We examined palladium-assisted biaryl coupling reactions of 3-methoxy and 3-methoxycarbonyl benzanilides, and propose an aspect of the mechanism involved in forming a biaryl bond using Pd reagent.
Published online: 1st September, 2006
■ Evaluation of Strategies for the Synthesis of the Guanidine Hemiaminal Portion of Palau’amine
Brian A. Lanman and Larry E. Overman*
*Department of Chemistry, University of California, Irvine, 516 Rowland, Irvine California 92697, U.S.A.
Abstract
Potential methods for the generation of the guanidine hemiaminal functionality of palau’amine (1) from a spirocyclic thiohydantoin precursor are examined using a spirobicyclic model system, culminating in the identification of an efficient means of effecting this transformation.
Published online: 2nd November, 2006
■ A Facile Synthesis of 2-Acyl and 2-Alkylaminobenzimidazoles for 5-Lipoxygenase Inhibitors
Jin Ha Lee, Mi Hyun Ahn, Eun Hyun Choi, Hea-Young Park Choo, and Gyoonhee Han*
*Department of Biotechnology, College of Engineering, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, Korea
Abstract
2-Acylaminobenzimidazoles (2a-r) have been synthesized from o-phenylenediamines (4) with benzoylcarbonimidodithioic acid dimethyl ester (5a) or dimethyl isobutyrylcarbonimidodithioic acid dimethyl ester (5b) in good yield. 2-Alkylaminobenzimidazoles could be prepared by the reaction of o-Phenylenediamines (4a, b) with benzyl isothiocyanate in moderate yields 8a, b or the reaction of 2-chlorobenzimidazole (9) with benzylamines (10a, b) in moderate yield 11a, b. Finally, the carbamate derivative of 2-aminobenzimidazole (13) was prepared by the reaction with pseudourea (12) in low yield. Most of the prepared analogues were evaluated in leukotriene inhibition assay and it found that benzamide derivatives (2a-i) are quite active among others.
Published online: 29th September, 2006
■ One-Step Syntesis of 4,5-Disubstituted Pyrimidines Using Commercially Available and Inexpensive Reagents
Phil S. Baran,* Ryan A. Shenvi, and Steven A. Nguyen
*Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Road, BCC-169, La Jolla, CA 92037, U.S.A.
Abstract
4,5-Disubstituted pyrimidines are synthesized from the corresponding ketone in one-step using inexpensive reagents (formamidine acetate, n-propanol, heat). Contrasted to other methods, this process appears quite amenable to large-scale use in industrial settings.