Regular Issue

Vol. 32, No. 6, 1991

21 data found. 1 - 21 listed
Communication | Regular issue | Vol 32, No. 6, 1991, pp. 1055 - 1058
Published online:
DOI: 10.3987/COM-91-5715
5-Bromomethyl-2-iminotetrahydrofuran Hydrobromide: A Useful Cyclic Imidate in the Synthesis of Benzazole-fused Heterocycles

Giancarlo Fantin, Marco Fogagnolo, Alessandro Medici,* and Paola Pedrini

*Dipartimento di Chimica, Università di Ferrara, 44100 Ferrara, Italy


The reaction of the title cyclic imidate with o-phenylene dinucleophiles affords the 2-substituted benzazoles (3a-c). Thermal cyclization of 3 via N-azolium salt to saturated benzazole-azines is also described.

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Communication | Regular issue | Vol 32, No. 6, 1991, pp. 1059 - 1062
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DOI: 10.3987/COM-91-5730
Photochemical Reactivity of Halofuran and Halothiophene Derivatives with Benzimidazole

Maurizio D’Auria

*Centro CNR per lo Studio della Chimica delle Sostanze Organiche Naturali, Dipartmento di Chimica, Università degli Studi di Roma "La Sapienza", Piazzale Aldo Moro 5, 00185 Roma, Italy


A photochemical approach to the synthesis of 5-(4-benzimidazolyl)-2-thiophene and 2-furan derivatives is described.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1063 - 1079
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DOI: 10.3987/COM-90-5512
Heterocycles from Nitrile Imines. Part III. Substituent Effect on Ring-Chain Tautomerism of 1,2,3,4-Tetrahydro-s-tetrazines

Mustafa M. El-Abadelah,* Ahmad Q. Hussein, and Haythem A. Saadeh

*Chemistry Department, Faculty of Science, University of Jordan, Amman 11942, Jordan


Selected series of 6-substituted 4-aryl-3-heteroaryl-1-methyl-1,2,3,4-tetrahydro-s-tetrazines (V:1-12) were synthesized via direct interaction between appropriate nitrile imine and model methylhydrazones. The extent of "ring-chain" tautomerism, as evidenced from nmr spectral data of V, is dependent on the nature of substituents at N-4, C-3, and C-6. The results reveal that: (i) The concentration of the cyclic tautomer tends to decrease as the basicity of the arylated N-4 decreases. (ii) For C-3 substituents, the cyclic tautomer ratio decreases in the order: phenyl>pyridyl>furyl>thienyl. (iii) For C-6 substituents, the cyclic ratio decreases in the order: C6H5>CO2Me>COMe. These trends are interpreted in terms of conjugative and electronic effects.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1081 - 1088
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DOI: 10.3987/COM-90-5571
Synthesis of Novel 5-Mercapto-s-triazolo[3,4-c]-as-triazino[5,6-b]indoles and Their Mannich Bases

B. Shivarama Holla* and K. Venkatramana Udupa

*Department of P. G. Studies and Research in Chemistry, Mangalore University, Mangalagangothri, 574 199(DK), Karnataka Statte, India


Reaction of as-triazino[5,6-b]indol-3-ylhydrazines with carbon disulphide in the presence of methanolic potassium hydroxide gave the title compounds through angular cyclization. On subjecting the title compounds to Mannich reaction, the NH of the triazole ring underwent aminomethylation reaction. This is further confirmed by chemical routes and by recording the uv spectra of linearly and angularly cyclized products. Structures of all the newly synthesized compounds are established on the basis of elemental analysis, 1H nmr and mass spectral data. Few selected compounds are screened for their antiviral and antibacterial properties.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1089 - 1099
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DOI: 10.3987/COM-90-5626
The Studies of Carbenoid Reactions of α-O-Allyl- or α-N-Allyl-α’-diazopropanone Derivatives Catalyzed by Various Metal Ions

Yung-Son Hon* and Rong-Chi Chang

*Institutue of Chemistry, Academia Sinica, 128, Yan-Chiu-Yuan Road, Sec II, Nankang, Taipei,11529, Taiwan, R.O.C.


Both cupric acetylacetonate and palladium (II) acetate are good catalysts to induce the carbon-carbon double bond addition reaction for α-O-allyl- or α-N-allyl-α’-diazopropanone derivatives. The heteroatom did not play an important role in enhancing the carbon-hydrogen bond insertion for compound (3).

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1101 - 1107
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DOI: 10.3987/COM-90-5609
Reactions with Coumarins: Synthesis of Several New Annelated Pyridine and Pyrrolylcoumarin Derivatives

Nabila A. Ismail,* Fathy A. Khalifa, and Asmaa A. Magd El Din

*Department of Chemistry, Faculty of Science, University of Zagazig, Zagazig, Egypt


Benzopyronopyridine, pyrazolo[3,4-d]pyridine, isoxazolo[5,4-b]pyridine, pyrido[2,3-d]pyrimidine and pyrrolylcoumarin derivatives were synthesized from 3-acetylcoumarin and its derivatives with different reagents.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1109 - 1116
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DOI: 10.3987/COM-91-5670
Synthesis of the Alkaloids (±)-Deplancheine and Flavopereirine

Parasuraman Jai Sankar, Sankar K. Das, and Venkatachalam S. Giri*

*Indian Institute of Chemical Biology, Calcutta-700 032, India


Desulfurization of 3-acetyl-1,2,6,7,12,12b-hexahydroindolo[2,3-a]quinolizine-2-ethylene thioketal (6) followed by NaBH4 reduction afforded (±)-deplancheine (1) whereas NaBH3 CN reduction followed by dehydration, desulfurization and DDQ oxidation yielded flavopereirine (2).

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1117 - 1122
Published online:
DOI: 10.3987/COM-91-5696
Addition Reactions of 8-Aryliminotropones with Carbon Disulfide to Give Thiazolidine-2-thione and 4-Thiazoline-2-thione Derivatives

Kazuaki Ito, Katsuhiro Saito,* and Kensuke Takahashi

*Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan


[8π+2π]-Type cycloaddition reactions of 8-aryliminotropones with carbon disulfide proceeded quantitatively to afford thiazolidine-2-thione derivatives, which turned to 4-thiazoline-2-thione derivatives via 1,5-hydrogen shift upon further heating.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1123 - 1130
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DOI: 10.3987/COM-91-5697
Acid-Base Properties of 4-Substituted Indoles

Manuel Balón,* Carmen Carmona, Jose Hidalgo, Maria A. Muñoz, and Pilar Guardado

*Departmento de Química Física, Facultad de Farmacia, Universidad de Sevilla, 41012 Sevilla, Spain


The protonation and deprotonation equilibria of a set of 4-substituted indoles have been studied spectrophotometrically at 25 °C. Ionization data have been analyzed by the Hammett acidity function and the excess acidity methods. The existence of close relationships between the Hammett’s σM constants of the substituents and the ionization constants for both types of aicd-base equilibria is reported.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1131 - 1136
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DOI: 10.3987/COM-91-5704
Stereoselective Bridging of Tetrahydro-1,5-benzodiazepines

Nagabushanam Kalyanam* and Sulur G. Manjunatha

*Research and Development Centre, Southern Petrochemicals Corporation Ltd., Maraimalai Nagar, Tamil Nadu 603 209, India


A reaction of tetrahydro-1,5-benzodiazepines with aromatic aldehydes which yields the hitherto unknown 1,5-methanotetrahydro-1,5-benzodiazepines as a single stereoisomer is desceribed. The stereochemistry of the products is established using proton nmr spectra.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1137 - 1141
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DOI: 10.3987/COM-91-5706
The Natural Occurrence and Partial Synthesis of 1α,4(S),6β,14α,16β-19,20-Didehydro-1,6,14,16-tetramethoxy-4-[[[2-(3-methyl-2,5-dioxopyrrolidinyl)benzoyl]oxy]methyl]aconitane-7,8-diol; Concerning Anhweidelphinine

Fung Sun, Yili Bai, and Michael Benn*

*Department of Chemistry, University of Calgary, Calgary, Alberta, T2N 1N4, Canada


The title compound, alkaloid-Y, which is probably identical with anhweidelphinine, was isolated from Delphinium nuttalianum and its structure was proven by its conversion into methyllycaconitine, and also by its preparation from that alkaloid.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1143 - 1151
Published online:
DOI: 10.3987/COM-91-5710
A Highly Stereoselective Synthesis of (±)-Normalindine

Allan W. Rey, Walter A. Szarek,* and David B. MacLean*

*Department of Chemistry, Queen‘s University, Kingston, Ontario K6L 3N6, Canada


Methyllithium reacted with (±)-dihydronaucléfine (5) to form, upon alkaline processing, a mixture of compounds, one having an exocyclic methylene group at C-5 (9) and the other, a C-5 — N iminiun compound having a methyl group at C-5 (10). Treatment of this mixture with either hydrogen over palladium catalyst or cyanoborohydride provided (±)-normalindine [(±)-1] in a highly stereoselective and efficient manner.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1153 - 1158
Published online:
DOI: 10.3987/COM-91-5712
Practical Synthesis of 3-Amino-5-tert-butylisoxazole from 4,4-Dimethyl-3-oxopentanenitrile with Hydroxylamine

Akira Takase,* Akira Murabayashi, Shinzaburo Sumimoto, Shiro Ueda, and Yasuo Makisumi

*Aburai laborotories, Shionogi Research Laboratories, Shionogi & Co. Ltd., Gotanda, Koka-cho, Shiga 520-34, Japan


A good yield of 3-amino-5-tert-butylisoxazole (3) was obtained regioselectively from a reaction of 4,4-dimethyl-3-oxopentanenitrile (1) with hydroxylamine in the aqueous solution of which was adjusted to weak basic, followed by treatment of the resulting 4,4-dimethyl-3-oxopentaneamidoxime (2) with hydrochloric acid.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1159 - 1166
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DOI: 10.3987/COM-91-5713
A New Synthesis of Precocene II and Precocene III Based on the Photo-Fries Rearrangement of a Sesamol Ester

Miguel A. Miranda,* Jaime Primo, and Rosa Tormos

*ETSII, Departmento de Química, Universidad Politécnica de Valencia, Apartado 22012, E-46071 Valencia, Spain


The photo-Fries rearrangement of the sesamol ester of 3-methylcrotonic acid (2) in the presence of potassium carbonate affords a mixture of the o-hydroxyketones (3c) and (3d). Basic cyclization of the latter leads to the chromanones (4c) or (4d), respectively. Treatment of 4c with alkoxide/alcohol results in the regioselective cleavage of the methylenedioxy ring, to give the corresponding 7-alkoxy derivatives (4e) or (4f). Subsequent methylation with methyl iodide gives rise to 4a or 4b and final reduction/dehydration by conventional methods affords the target compounds Precocene II (1a) or Precocene III (1b).

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1167 - 1171
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DOI: 10.3987/COM-91-5716
Stereostructure of (-)-Multiflorine N-Oxide: A New Lupin Alkaloid from Lupinus hirsutus

Satoshi Takamatsu, Kazuki Saito,* Shigeru Ohmiya, and Isamu Murakoshi

*Faculty of Pharmaceutical Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan


A new lupin alkaloid, (-)-multiflorine N-oxide (1) was isolated from the seedlings of Lupinus hirsutus together with twelve known alkaloids. The structure of 1 was determined by spectroscopic methods and by chemical transformations.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1173 - 1179
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DOI: 10.3987/COM-91-5727
Reductive Cleavage of Isoxazolo[3,4-d]pyridazinones: A Synthetic Approach to Various 4,5-Functionalized 3(2H)-Pyridazinones

Vittorio Dal Piaz,* Giovanna Ciciani, and Maria Paola Giovannoni

*Dipartimento di Scienze Farmaceutiche, Università di Firenze, Via Gino Capponi 9, I-50121 Firenze, Italy


4-Aminopyridazin-3(2H)-ones substituted at position 5 with a variety of oxygenated carbon chains were obtained in good yields by reductive opening of the pentatomic ring of isoxazolo[3,4-d]pyridazinones (1). Starting from ethyl 4-acylisoxazole-3-carboxylates, several 4,5-functionalized 3(2H)-pyridazinones (3) are obtained in a one step by treatment with the appropriate hydrazine and Pd/C.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1181 - 1187
Published online:
DOI: 10.3987/COM-91-5729
5-Hydroxy-1,3-oxazin-6(6H)-ones from 6-Aza-1,5-dioxaspiro[2.4]hept-6-en-4-ones

Nicoletta Almirante, Maria Luisa Gelmi,* and Claudio Scarpellini

*Istituto di Chimica Organica, Facoltà di Farmacia, Università degli Studi di Milano, Via Venezian 21, I-20133 Milano, Italy


4-Alkylideneisoxazol-5(4H)-ones (1) were epoxidized with t-butyl hydroperoxide yielding 6-aza-1,5-dioxaspiro[2.4]hept-6-en-4-ones (2). By heating, compounds (2) rearranged to 5-hydroxy-1,3-oxazin-6(6H)-ones (3).

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1189 - 1194
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DOI: 10.3987/COM-91-5733
Structure of Bisclausarin, a New Bicoumarin from Citrus Plant

Motoharu Ju-ichi,* Yuko Takemura, Masayoshi Okano, Narihiko Fukamiya, Chihiro Ito, and Hiroshi Furukawa*

*Faculty of Pharmaceutical Science, Mukogawa-Women’s University, 11-68 Koushien Kyuban-Cho, Nishinomiya, Hyogo 663-8179, Japan


A new type bicoumarin, named bisclausarin, was isolated from the roots of Citrus hassaku (Rutaceae) and the structure was elucidated as 1 on the basis of spectroscopic data.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1195 - 1198
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DOI: 10.3987/COM-91-5737
Synthesis of 11β-Hydroxy Erythrina Alkaloid, Erythrartine, and Its O-Acetate (Erythrascine?)

Kimiaki Isobe,* Kunihiko Mohri, Kazumi Suzuki, Mitumasa Haruna, Kazuo Ito, Shinzo Hosoi, and Yoshisuke Tsuda*

*Showa Pharmaceutical University, 3-3165, Higashi-tamagawagakuen, Machida, Tokyo 194-8543, Japan


Oxidation of an erythrinan alkaloid erysotramidine (4) with CAN in AcOH-MeCN gave, in moderate yield, the 11β-acetoxy derivatives (5b), which was transformed into erythratine (8). Its O-acetate (O-acetylerythrartine) was not identical with erythrascine in the 1H-nmr spectra, presenting an ambiguity on the reported structure of erythrascine.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1199 - 1202
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DOI: 10.3987/COM-91-5739
[4+2] Cycloaddition Reaction of N-Ethoxycarbonyl-2-[(1-trimethylsiloxy)vinyl]pyrrole with Acetylenic Carboxylates

Masatomi Ohno, Sadahiro Shimizu, and Shoji Eguchi*

*Institute of Applied Organic Chemistry, Faculty of Engineering, Nagoya University, Chikusa, Nagoya, Aichi 464-8601, Japan


The title reaction resulted in the formation of functionalized indoles through rearomatization via ene reaction followed by elimination reaction or via competitive air oxidation reaction. Under an atmosphere of oxygen the latter process predominated to give majorly 7-hydroxy substituted indoles.

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Paper | Regular issue | Vol 32, No. 6, 1991, pp. 1203 - 1214
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DOI: 10.3987/COM-91-5742
Synthesis of Saframycins. VII. The Synthesis of Novel Renieramycin Congeners

Naoki Saito, Reiko Yamaguchi, and Akinori Kubo*

*Meiji College of parmacy, 1-35-23 Nozawa, Setagaya-ku, Tokyo 154, Japan


Synthesis of the marine alkaloid renieramycin congeners (13a-c) has been investigated satrting from the alcohol (14a) which was the key intermediate for saframycin B synthesis.

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21 data found. 1 - 21 listed