Regular Issue

Vol. 32, No. 9, 1991

22 data found. 1 - 22 listed
Communication | Regular issue | Vol 32, No. 9, 1991, pp. 1671 - 1679
Published online:
DOI: 10.3987/COM-91-5692
Zinc Mediated Reduction of Bromohydrins in Azetidinones and Penems. Application to the Synthesis of FCE 22891

M. Altamura, Angelo Bedeschi,* M. Marchi, G. Visentin, and F. Francalanci

*Farmitalia Carlo Erba R&D, Via dei Gracchi 35, 20146 Milano, Italy


A route to penems is described in which dehalogenative reduction of bromohydrins is carried out after ring opening of the penam nucleus. Reduction on some newly synthesized bromopenems suffered from low yields. Better yields and acceptable stereoselectivity were obtained on free-hydroxyethyl azetidinone substrates. Some parameters of the reduction are discussed.

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Communication | Regular issue | Vol 32, No. 9, 1991, pp. 1681 - 1685
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DOI: 10.3987/COM-91-5768
Reaction of 7-Substituted 4-Hydroxy-1,4-benzoxazine-3-ones in Strongly Acidic Media

Andrés Quiroz and Hermann M. Niemeyer*

*Departamento de Química, Facultad de Ciencias, Unversidad de Chile, Casilla 653, Santiago, Chile


Kinetic and product studies of the reaction of 7-substituted 4-hydroxy-1,4-benzoxazin-3-ones in strongly acidic media produced biphasic Hammett plots which indicated the intermediacy of a highly electrophilic nitrogen compound with nitrenium ion character.

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Communication | Regular issue | Vol 32, No. 9, 1991, pp. 1687 - 1691
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DOI: 10.3987/COM-91-5769
Decomposition of 7-Nitro-2,4-dihydroxy-1,4-benzoxazin-3-one in Aqueous Solutions

Héctor R. Bravo and Hermann M. Niemeyer*

*Departamento de Química, Facultad de Ciencias, Unversidad de Chile, Casilla 653, Santiago, Chile


Kinetic and product studies indicate that the title compound decomposes in aqueous solutions to give 5-nitro-2-aminophenol with the intermediacy of N-(2-hydroxy-4-nitrophenyl)carbamic acid.

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Communication | Regular issue | Vol 32, No. 9, 1991, pp. 1693 - 1696
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DOI: 10.3987/COM-91-5795
Oxidative Cyclization of Trifluoroacetylated Aldehyde Dimethylhydrazones. A New Convenient Synthesis of Trifluoromethylated Oxadiazine Derivatives

Yasuhiro Kamitori, Masaru Hojo,* Ryoichi Masuda, Toshihiko Fujitani, and Katsumichi Sukegawa

*Department of Industrial Chemistry, Faculty of Engineering, Kobe University, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan


Trifluoromethylated oxadiazine derivatives (3) were conveniently synthesized by NaIO4-mediated cyclization of hydrazones (1) which are readily obtained by trifluoroacetylation of aldehyde dimethylhydrazones.

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Communication | Regular issue | Vol 32, No. 9, 1991, pp. 1697 - 1698
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DOI: 10.3987/COM-91-5796
A Facile Synthesis of 2,4-Oxazolidinediones

Hidenori Okamoto* and Shozo Kato

*Tsukuba research Laboratory, Tokuyama Soda Co., Ltd., 40 Wadai, Tsukuba, Ibaraki 30042, Japan


2,4-Oxazolidinediones bearing 1-aryl-2-methylpropen-1-yl substituent at 3-position were obtained easily by the reaction of 2-chloro-N-(1-aryl-2-methyl-1-propenyl)acetamides with both chloroformic acid ester and potassium carbonate in DMF.

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Communication | Regular issue | Vol 32, No. 9, 1991, pp. 1699 - 1703
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DOI: 10.3987/COM-91-5798
Preparation of Tetrahydroisoquinolines from N-(tert-Butoxycarbonyl)-2-methylbenzylamines

Robin D. Clark* and Jahangir

*Institute of Organic Chemistry, Syntex Research, Palo Alto, California 94304, U.S.A.


Dilithiation of N-(tert-butoxycarbonyl)-2-methylbenzylamine (1a) followed by treatment with N,N-dimethylformamide affords 2-(tert-butoxycarbonyl)-3-hydroxytetrahydroisoquinoline (3a). Dehydration and reduction of 3a afford BOC-tetrahydroisoquinoline (5a). The methodology is also applicable to synthesis of chloro and fluoro substituted tetrahydroisoquinolines (5b,c), 3 and 4 substituted derivatives (8, 10), and the hexahydro-2H-benzoquinolizine ring system (13).

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Communication | Regular issue | Vol 32, No. 9, 1991, pp. 1705 - 1707
Published online:
DOI: 10.3987/COM-91-5814
A Total Synthesis of (-)-Physostigmine

Manabu Node,* Akichika Itoh, Yukio Masaki, and Kaoru Fuji

*Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan


A total synthesis of (-)-physostigmine (7) was accomplished a chiral nitro olefin (1).

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1709 - 1717
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DOI: 10.3987/COM-90-5440
Proximity Effect in the Hydrogen-Deuterium Exchange and Deethoxycarbonylation of Peri-substituted Naphthalene with the 1,2,3-Triazole Ring

Yoshinobu Nagawa,* Koichi Honda, and Hiroshi Nakanishi

*National IChemical Laboratory for Industry, 1-1, Higashi, Tsukuba, Ibaraki, 305-8566, Japan


The H-D exchange reaction and the deethoxycarboxylation in D2O of 1-[8-(4-ethoxycarbonyl-1H-1,2,3-triazol-1-yl)-1-naphthyl]-3-methyl-4-ethoxycarbonyl-1H-1,2,3-triazolium salts (1) were studied by 1H nmr spectroscopy and compared with those of 1-(1-naphthyl)-3-methyl-4-ethoxycarbonyl-1H-1,2,3-triazolium salts (2). The reaction rates of 1 are found to be much faster than those of 2. The results suggest that the triazole ring in 1 interacts sterically with the N-methylated triazole ring to accelerate the reactions.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1719 - 1728
Published online:
DOI: 10.3987/COM-91-5752
Synthesis and Properties of Pyrimido[4,5-b][1,4]oxazin-7-one Derivatives. A Novel Heterocyclic System

Manuel Melguizo, Manuel Nogueras,* and Adolfo Sánchez

*Departamento de Química Orgánica, Facultad de Ciencias Experimentales de Jaén, 23071 Jaén, Spain


The synthesis of two pyrimido[4,5-b][1,4]oxazin-7-one derivatives (5 and 10) from 4,5-diaminopyrimidin-6(1H)-one derivatives (2 and 8) and ethyl pyruvate is reported. By treatment of a 5-amino-4-(xylosylamino)pyrimidine (2) with ethyl pyruvate, a 8-xyloxylpteridine derivative (4) or a 4-(xylosylamino)pyrimido[4,5-b][1,4]oxazin-7-one derivative (5) can be obtained depending on solvent employed. This solvent-dependent regioselectivity was rationalized on the basis of instability of compound 5 in hydroxylic media. This feature of instability is analized and conditions necessary for obtaining pyrimido[4,5-b][1,4]oxazin-7-one derivatives are reported.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1729 - 1736
Published online:
DOI: 10.3987/COM-91-5760
The Pyrrolizidine Alkaloids from Senecio racemosus

Wasim Ahmed, Zaheer Ahmed, Abdul Malik,* Fatma Ergun, and Bilge Sener*

*H. E. J. Postgraduate Institute of Chemistry, University of Karachi, Karachi-75270, Pakistan


Two new pyrrolizidine alkaloids, racemocine and racemonine, have been isolated from Senecio racemosus. Their structures (1 and 2) have been assigned on the basis of spectral studies including 2D-nmr.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1737 - 1744
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DOI: 10.3987/COM-91-5770
Synthesis of (Z)-3-Butylidene-6,7-dihydroxyphthalide

Yoshimitsu Ogawa,* Kunio Hosaka, Masao Chin (Chen Zhengxiong), and Horoshi Mitsuhashi

*Research Institute for Biology and Chemistry, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki 300-1192, Japan


(Z)-3-Butylidene-6,7-dihydroxyphthalide (2) was first synthesized from 6,7-dimethoxyphthalide (4) and its structure was synthetically confirmed.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1745 - 1755
Published online:
DOI: 10.3987/COM-91-5773
Pyrazoles and Isoxazoles Derived from 2-Hydroxyaryl Phenylethynyl Ketones: Synthesis and Spectrophotometric Evaluation of Their Potential Applicability as Sunscreens

Hermenegildo García, Sara Iborra, Miguel A. Miranda,* Isabel M. Morera, and Jaime Primo

*Departamento de Quimica/ Instituto de Tecnologia Quimica , UPV-CSIC, Universidad Politécnica de Valencia, Apartado 22012, E-46071-Valencia, Spain


Reaction of the acetylenic ketones (1) with hydrazine or hydroxylamine leads to the pyrazoles (2) or the isoxazoles (3), respectively. Spectrophotometric evaluation of the UV-photoprotecting ability as compared to p-aminobenzoic acid (PABA) shows that the predicted effectiveness of 2 and the 3-phenylisoxazoles (3B) is very close to that of PABA, while that of the 5-phenylisoxazoles (3A) is clearly lower. The pyrazoles (2) are more stable than PABA upon UV-irradiation in cyclohexane solution.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1757 - 1764
Published online:
DOI: 10.3987/COM-91-5775
Diastereoselectivity in the Reaction of 3-Methyl-5-(methyl- or phenyl)isoxazol-4-yllithium and α,α’-Dimethylcycloalkanones

Cecilia Polo, Vicente Ramos, Tomás Torroba,* Matías L. Rodoríguez, Ricardo Bossio, Stefano Marcaccini, and Roberto Pepino

*Departmento de Quimica Orgánica. Facultd de Veter inaria, Universidad de Extremadura, 10071 Cáceres, Spain.


Addition of 3-methyl-4-lithio-5-(methyl- or phenyl)isoxazoles to stereoisomeric mixures of α,α’-dimethylcycloalkanones afforded meso 1S*,2R*,(5 or 6)S*-2,(5 or 6)-dimethyl-1-[3’-methyl-5’-(methyl- or phenyl)isoxazol-4’-yl]cycloalkan-1-ols. In one case none of meso form, but only the racemic 2,6-dimethyl-1-(3’-methyl-5’-phenylisoxazol-4’-yl)cyclohexan-1-ol was obtained. This compound showed restricted rotation phenomena at room temperature.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1765 - 1772
Published online:
DOI: 10.3987/COM-91-5784
Heterocyclic Rearrangements — The Rearrangement of 3-Aroylaminoisoxazoles into 2-Aroylaminooxazoles

Silvestre Buscemi, Vincenzo Frenna, and Nicolò Vivona*

*Dipartimento di Chimica Organica, Università digli Studi di Palermo, Via Archirafi 20 90123 Palermo, Italy


When treated with t-BuOK in DMF at 110-120 °C, 3-aroylamino-5-methylisoxazoles gave good yields of 2-aroylamino-5-methyloxazoles as the ring rearrangement products. The same isoxazole to oxazole ring isomerization has been also observed in a photoinduced reaction.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1773 - 1776
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DOI: 10.3987/COM-91-5786
A Novel Synthesis of Azaacridones Using 1,4-Dipolar Aryne Cycloadditions

Subhash P. Khanapure, Baburao M. Bhawal, and Edward R. Biehl*

*Department of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, TX 75275-0314, U.S.A.


A novel approach for the synthesis of azaacridones based on 1,4-dipolar cycloaddition of methyl N-lithiated 2-(aminotrimethylsilyl)nicotinate (2a) and methyl 3-(aminotrimethylsilyl)pyrazine-2-carboxylate (2b) which function as 1,4-dipole equivalents, with arynes is reported.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1777 - 1780
Published online:
DOI: 10.3987/COM-91-5792
Use of Mercaptoacetaldehydes Dimer in a Novel Thienoannelation Sequence. A Short Synthesis of Ticlopidine

Owen W. Gooding* and Colin C. Beard

*Institute of Organic Chemistry, Syntex Research, Palo Alto, California 94304, U.S.A.


A short synthesis of ticlopidine (1) was achieved by condensation of mercaptoacetaldehyde dimer (2) with piperidone (3b) in the presence of lithium diisopropylamide followed by dehydration.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1781 - 1784
Published online:
DOI: 10.3987/COM-91-5797
New Acridone Alkaloids from Citrus yuko

Motoharu Ju-ichi,* Yuko Takemura, Chihiro Ito, and Hiroshi Furukawa

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


From the root barks of Citrus yuko (Rutaceae), tow new acridone alkaloids, named yukomine and citracridone-III, were isolated and their structures were elucidated as 1 and 2 on the basis of spectroscopic data.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1785 - 1792
Published online:
DOI: 10.3987/COM-91-5800
Synthesis of Ring-enlarged Cyclobut-A and Cyclobut-G Analogues as HIV Inhibitors. Part 4

Hassane Boumchita, Michel Legraverend,* and Emile Bisagni

*URA 1387, CNRS, Institut Curie, Section de Biologie, Centre Universitaire, Bât., 110-112, 91405 Orsay, France


Two ring-expanded analogues (compounds 13 and 14) of the anti-HIV agents Cyclobut-A and Cyclobut-G are described. They were synthesized from trans-3,4-bis(hydroxymethyl)cyclobutylamine which was obtained from threo-3,4-bis(methoxycarbonyl)hexane dioic acid. Neither compound (13, 14) was able to provide protection to CEM cells against HIV-1 infection.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1793 - 1804
Published online:
DOI: 10.3987/COM-91-5809
Tangutisine, a New Diterpenoid Alkaloid from Aconitum tanguticum (Maxim.) Stapf, W. T. Wang

Balawant S. Joshi, Di Hua Chen, Xiaolin Zhang, John K. Snyder, and S. William Pelletier*

*Institute for Natural Products Research, School of chemical Sciences, The University of Georgia, Chemistry Building, Athens, Georgia 30602-2556, U.S.A.


Tangutisine, isolated from Aconitum tanguticum, has been assigned the structure (1) on the basis of homonuclear 1H COSY, HETCOR, two dimensional nOe, 1H — 13C long range correlations (FLOCK) and selective INEPT nmr techniques.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1805 - 1812
Published online:
DOI: 10.3987/COM-91-5812
Selective Functionalization of 2,2’-Bithiophenes

Eugene Khor,* Siu Choon Ng, Hwee Chze Li, and Selenium Chai

*Department of Chemistry, National University of Singapore, 10 Kent Ridgh Crescent, 119260, Singapore


The selective functionalization of the 2,2’-bithiophene molecule is described. Selective alkyl substitution at the 3,3’ positions was achieved by sequential bromination of the 3,3’ and 5,5’ positions followed by debromination at the 5,5’ positions. The resultant 3,3’-dibromo-2,2’-bithiophene was transformed via a Grignard reaction to give a series of 3,3’-dialkyl-2,2’-bithiophenes. Finally, nitration of the active 5,5’ positions gave the corresponding 3,3’-dialkyl-5,5’-dinitro-2,2’-bithiophenes.

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1813 - 1820
Published online:
DOI: 10.3987/COM-91-5813
Synthesis of 2,5-Disubstituted 3-(4-Chlorobenzoyl)-2,3-dihydro-2-methyl-1,3,4-thiadiazole Derivatives

Kouhei Toyooka,* Yoshiyuki Takeuchi, Masayuki Shibuya, and Seiju Kubota

*Faculty of Pharmaceutical Sciences, University of Tokushima, Sho-machi, Tokushima 770-8505, Japan


2-Substituted 3-(4-chlorobenzoyl)-2,3-dihydro-5-methylthio-1,3,4-thiadiazoles (3) were used as key intermediates to prepare 2,5-disubstituted 3-(4-chlorobenzoyl)-2,3-dihydro-1,3,4-thiadiazoles (4) and (7).

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Paper | Regular issue | Vol 32, No. 9, 1991, pp. 1821 - 1830
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DOI: 10.3987/COM-91-5818
Metabolic Formation and Chemical Synthesis of 5,6-Cyclopenteno-4,11-dihydro-3H-pyrido[3,2-a]carbazol-3-one, the Major Intestinal Bacterial Metabolite of the Pyrolysis Mutagen 5,6-Cyclopenteno-11H-pyrido[3,2-a]carbazole (LYS-P-1)

David G. I. Kingston,* Yue-Zhong Shu, Roger L. Van Tassell, and Tracy D. Wilkins

*Department of Chemisry, Virginia Polytecnic Institute and State University, Blacksburg, Virginia 24061-0212, U.S.A.


Anaerobic incubation of the lysine pyrolysis mutagen 5,6-cyclopenteno-11H-pyrido[3,2-a]carbazole (Lys-P-1, 3) with human intestinal bacterial mixtures yielded the major metabolite 5,6-cyclopenteno-4,11-dihydro-3H-pyrido[3,2-a]carbazol-3-one (3-HO-Lys-P-1, 4). The metabolite (4) has been synthesized from 4-aminoindane in six steps. NAD and NADP significantly enhanced the metabolism, suggesting that the transformation of of 3 leading to 4 involves a hydration and subsequent dehydrogenation processes.

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22 data found. 1 - 22 listed