HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Regular Issue
Vol. 57, No. 6, 2002
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■ First Rotameric Anti Dimers and 3,9-Diazatetraasteranes from Unsymmetrically Substituted N-Acyl and N-Acyloxy-4-aryl-1,4-dihydropyridines
Andreas Hilgeroth,* Frank W. Heinemann, and Ute Baumeister
*Department of Pharmacy, Institute of Pharmaceutical Chemistry, Martin-Luther-University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle, Germany
Abstract
A series of unsymmetrically substituted N-acyl- and N-acyloxy-1,4-dihydropyridines (1) have been photochemically investigated. On irradiating the crystals of one derivative (1a) containing centrosymmetrical pairs of molecules with a distance of 3.894(3) Å between the potentially reacting double bonds favorable for a photodimerisation reaction, the formation of an anti-dimer (2a) was observed. Two other solid derivatives (1b, c) merely decomposed on irradiation to give substituted pyridine compound (3). Solution irradiation of 1,4-dihydropyridines (1) led to the centrosymmetric cage compounds 3,9-diazatetraasteranes (4) and to anti dimers (2) as main products, both existing as rotamers. Symmetric as well as rotameric properties of selected compounds (4) have been demonstrated by X-Ray crystal structure analysis and 1H NMR spectroscopy.
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■ Synthesis of 3-Substituted 5-Arylidene-1-methyl-2-thiohydantoins under Microwave Irradiation
Ahmed I. Khodair and John Nielsen*
*Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, DK-2800 Kgs. Lyngby, Denmark
Abstract
A mono-modal microwave oven was used to expedite the synthesis of small libraries of 3-substituted 1-methyl-2-thiohydantoins and 3-substituted 5-arylidene-1-methyl-2-thiohydantoins. In comparison with the traditional reflux methods, similar or higher yields were obtained.
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■ The Synthesis of 2,2-Disubstituted-3-nitrochromenes from Salicylaldehyde and 2,2-Disubstituted-1-nitroalkenes
Ming-Chung Yan, Yeong-Jiunn Jang, Wen-Yu Kuo, Zhijay Tu, Kao-Hsien Shen, Ting-Shen Cuo, Chuen-Her Ueng, and Ching-Fa Yao*
*Department of Chemistry, National Taiwan Normal University, 88, Sec. 4, Tingchow Road, Taipei, 116, Taiwan, R.O.C.
Abstract
Reactions of salicylaldehyde (1) with β-nitrostyrenes (2), (4), and (6) in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) without the use of solvent at 40 °C gave high yields of the corresponding 3-nitrochromenes, respectively. Other conjugated nitroalkenes were also used to react with salicylaldehyde under the similar conditions and the yields of substituted 3-nitrochromenes were moderate to high. 96% of cis-3-nitro-4-hydroxyflavane (11) was isolated as sole stereoisomer when 1 reacted with 2-nitromethyleneadamantane (10) under similar condition. When the reaction temperature was increased to 90 °C, 11 underwent dehydration to generate 74% of the corresponding 3-nitrochromene (12).
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■ Synthesis of Coumaran-5-ols — New Model Compounds for Bioantioxidants
Uta Schädel and Wolf D. Habicher*
*Institute of Organic Chemistry, Dresden University of Technology, Mommsenstr. 13, D-01062 Dresden, Germany
Abstract
Based on a Heck type reaction a new access to coumaran-5-ols has been developed. The reaction, its analytical and synthetical features as well as the nature of some by-products are discussed.
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■ Dimeric Stilbenes from Stem Lianas of Gnetum africanum
Ibrahim Iliya, Toshiyuki Tanaka,* Munekazu Iinuma, Zulfiqar Ali, Miyuki Furasawa, and Ken-ichi Nakaya
*Gifu Prefectrual Institute of Health and Environmental Sciences, 1-1 Nakafudogaoka, Kakamigahara, Gifu 504-0838, Japan
Abstract
Two new stilbene dimers; gneafricanins A, B and bisisorhapontigenin B were isolated from the stem lianas of Gnetum africanum (Gnetaceae) along with eight known stilbenoids; longusol A, gnetin C, gnetin D, gnetin E, gnetofolin E, gnetol, isorhapontigenin and resveratrol. The structures of the new compounds were determined by spectral analysis.
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■ Synthesis of 1,2-Dihydrobenz[c]azepin-3-one via Acid-catalyzed Cyclization of N-Arylmethyl-N-methyl-3-phenylsulfanylacrylamide
Yoshie Horiguchi,* Toshiaki Saitoh, Tomoko Kashiwagi, Lisa Katura, Mayumi Itagaki, Jun oda, and Takehiro Sano
*Showa Pharmaceutical University, 3-3165, Higashi-tamagawagakuen, Machida, Tokyo 194-8543, Japan
Abstract
Treatment of N-arylmethyl-N-methyl-cis-3-phenylsulfanyl acrylamide (5) with p-toluenesulfonic acid induced two reactions; cyclization to 1,2-dihydrobenz[c]azepin-3-ones (7) and N-dearylmethylation to N-methylacrylamides (9 and 10) depending on the structures of the substrates. The route provides a simple method of preparing 6-methoxy- (7e), 8-methoxy- (7d), 6,8-dimethoxy- (7f), and 8,9-dimethoxy-N-methyl-1,2-dihydrobenz[c]azepin-3-ones (7g), although the scope is limited by some side reactions.
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■ Synthesis of E/Z 3-(1H-Benzotriazol-1-yl)-3-(pyridin-4-yl)acrylonitriles and E/Z 2-(3-Imino-2-benzofuran-1(3H)-ylidene)acetonitriles. An Unusual Case of Displacement of the Benzotriazole Ring
Antonio Carta, Paolo Sanna,* and Alessia Bacchi
*Department of Medicinal and Toxicological Chemistry, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy
Abstract
Synthesis of 3-(1H-benzotriazol-1-yl)-3-(pyridin-4-yl)acrylonitriles (E/Z 6) and 2-(3-imino-2-benzofuran-1(3H)-ylidene)acetonitriles (E/Z 20), by an unusual case of displacement of the benzotriazole ring, has been described. The X-Ray structure analysis of Z 20 and antimycobacterial activity of both E/Z 6 and E/Z 20 were also reported.
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■ One-Step Synthesis of Optically Active Cyclic Polyamines Containing Helicene
Shinobu Honzawa, Shinya Chiba, Hitoshi Okubo, and Masahiko Yamaguchi*
*Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan
Abstract
Chiral macrocyclic tetraamines containing four helicenes were effectively synthesized in one-step. Reductive coupling of a (P)-helicenedi(methylamine) and a (P)-helicenedicarbaldehyde gives a cyclic (P,P,P,P)-tetramer in 88% yield. The (P,M,P,M)-diastereomer was effectively synthesized from the (M)-diamine and the (P)-dialdehyde in 66% yield. The intermediate (P,P,P,P)-imine and (P,M,P,M)-imine can be isolated also in high yields. The reductive coupling of achiral arenes, m-phenylenedi(methylamine) and m-phenylenedicarbaldehyde gives the cyclic tetramer in 47% yield, which is accompanied by the higher cyclic oligomers containing hexamer (18%) and octamer (3%). The condensed benzene ring system of the helicene appears to play an important role in the high yielding cyclic tetramerization.
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■ Synthesis of 2,4-Disubstituted Indoles via Thermal Cyclization of N-Trifluoroacetyl Enehydrazines
Okiko Miyata, Norihiko Takeda, and Takeaki Naito*
*Kobe Pharmaceutical University, Motoyamakita, Higashinada, Kobe 658-8558, Japan
Abstract
Synthesis of naturally occurring indoles, 2,4-dimethylindole and 4-hydroxymethyl-2-methylindole by applying thermal cyclization of N-trifluoroacetyl enehydrazines is described.
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■ Synthesis of New Friedländer Synthon and Its Application towards the Construction of Pyrido[3,2-c]acridines
Jong Keun Son, Jae Keun Son, and Yurngdong Jahng*
*College of Pharmacy, Yeungnam University, Kyongsan 712-749, Korea
Abstract
A new Friedläder synthon, 4-aminoacridine-3-carbaldehyde was prepared in 4 steps from 3-methylacridine in 38% overall yield, which was readily condensed with acetylaromatics to yield 2-arylpyrido[3,2-c]acridines.
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■ Two New C19-Diterpenoid Alkaloids from Aconitum racemulosum Franch var. Pengzhouense
Chong-Sheng Peng, Qiao-Hong Chen, Dong-Lin Chen, Xi-Xian Jian, and Feng-Peng Wang*
*Department of Chemistry of Medicinal Natural Products, West China College of Pharmacy, Sichuan University, No. 17, Duan 3, Remin Nan Road, Chengdu 610041, China
Abstract
Two new C19-ditepenoid alkaloids, racemulolines A (1) and B (2), were isolated from the whole plants of Aconitum racemulosum Franch var. pengzhounense, and their structures were elucidated by spectral analysis.
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■ Synthesis of Fused Heterocyclic Ring Systems Related to 6-Amino-1,4-dihydro-3-methyl-1-phenyl-4-thioxothiopyrano[4,3-c]pyrazole-7-carbonitrile
Maymona M. Kandeel, Ragaa A. Ahmed, and Mohamed Salah K. Youssef*
*Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt
Abstract
The title compound (1) was prepared and reacted with some reagents e.g Ac2O, HC(OC2H5)3 to give thiopyrano[4,3-c]pyrazole derivatives (2,10); PhNH2, NaOH, AcONH4/AcOH, H2NNH2.H2O to afford pyrazolo[4,3-c]pyridine derivatives (4,5,13,14). Also 1 reacted with CS2/CH3I, PhNCS, CCl3CN and H2NHNCSNH2 to provide the pyrazolo[3',4':4,5]thiopyrano[2,3-d]pyrimidine derivatives (7,9,12) and pyrazolo[4,3-c][1,2,4]triazolo[1,5-a]pyridine derivative (8). On the other hand the o-diamino compound (14) was used for building up a third heterocyclic ring [eg. triazene (15-17), triazole (18,19) and tetrazole (20)] through its interaction with some electrophilic reagents.
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■ The Reactions of Hydroiodide of 2-Amino-1-substituted Guanidine Derivatives with Aromatic Isothiocyanates
Maria Dobosz* and Monika Wujec
*Department of Organic Chemistry, Faculty of Pharmacy, Medical University in Lublin, 6 Staszica Str., 20-081 Lublin, Poland
Abstract
In the reaction of hydroiodide of methyl ester of S-methylthio- semicarbazide with primary amines hydroiodides of 2-amino-1-substitutedguanidine were obtained (1). These compounds were then converted to respective 3-arylamino-4-substituted Δ2-1,2,4-triazoline-5-thione and 3-benzylamino-4-substituted Δ2-1,2,4-triazoline-5-thione (2) in the reactions with isothiocyanates.
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■ An Efficient Synthesis of N-Boc-D-diphenylalanine from a Chiral Azirdine-2-carboxylate
Jae-Won Chang, Hyun-Joon Ha,* Chan Sun Park, Min Sung Kim, and Won Koo Lee*
*Department of Chemistry, Hankuk University of Foreign Studies, Yongin, Kyunggi-Do, 449-791, Korea
Abstract
N-Boc-D-diphenylalanine was prepared from a commercially available aziridine-2(S)-carboxylate through alkylation, regiospecific aziridine ring opening, and benzylic deoxygenation followed by oxidation in 57% overall yield.
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■ Synthesis of 1,2-Oxazines and Their N-Oxides
Petros G. Tsoungas
*Department of Research and Technology, Ministry of Development, Messogion Ave. 14-18, GR-115 10, Athens, Greece
Abstract
The available routes to the synthesis of partially saturated 1,2-oxazine isomers or their N-oxides as well as those of their aromatic counterparts are presented.