Special Issue

Alan R. Katritzky's Special Issues, Vol. 37, No. 2, 1994

66 data found. 1 - 30 listed Next Last
Communication | Special issue | Vol 37, No. 2, 1994, pp. 661 - 666
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DOI: 10.3987/COM-93-S13
The Three-Component Condensation of Monoterpenes with Formaldehyde and Cyclohexane-1,3-dione. A Simple Route to Polyketide Terpenes

Stefan Koser and H. M. R. Hoffmann*

*Institut fur Organische Chemie, Universität Hannover, Schneiderberg 1 B 3000 Hannover, Germany


The framework of polyketide terpenes was obtained by the title tandem reaction which was carried out in one-pot under optimized conditions. Even tetrasubstituted olefins react, sterically hindered octahydronaphthalene (6) giving tetracyclic propellane (7).

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 667 - 671
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DOI: 10.3987/COM-93-S42
Reaction of Pyrylium Salts with Amino Acid Derivatives Part 3. Ribonuclease A Inactivation by Trisubstituted Pyrylium Salts

Claudiu T. Supuran, Emil Pop, and Antonie Dinculescu*

*Pharmos Corporation, 2 Innovation Drive, Alachua, FL32615, U.S.A.


Treatment of ribonuclease A with 2,4,6-trisubstituted pyrylium salts completely inhibits the activity of this enzyme. The inactivation is probably due to the reaction of the ε-amino group of the active site Lys 41 residue with the pyrylium cation, leading to pyridinium derivatives which hinder the access of substrates to the active site of the enzyme

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 673 - 677
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DOI: 10.3987/COM-93-S45
Preparation of a Deoxynojirimycin Analog Containing an Imidazole Ring

Kevin Burgess,* David A. Chaplin, Alan D. Elbein, and Yucheng Zeng

*Department of Chemistry, Texas A & M University, College Station, Texas 77843-3255, U.S.A


The deoxynojirimycin analogs (4) and (5) were prepared via addition of a metallated imidazole to an aldehyde; these compounds were screened for inhibition of glycosidase enzymes and anti-HIV activities.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 679 - 681
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DOI: 10.3987/COM-93-S65
Total Synthesis of (±)-cis-, trans-Cembranolides (±)-Sarcophytonin B from Geranylgeraniol

Kiyoshi Nishitani, Toshihiko Konomi, Kiyonobu Okada, and Koji Yamakawa*

*Faculty of Pharmaceutical Sciences, Science University of Tokyo, 12, Ichigaya Funagawara-machi, Shinjuku-ku, Tokyo 162-0826, Japan


(±)-cis-Cembranolide (I) was synthesized via Cr(II) mediated intramolecular macrocyclization of ω-formyl-β-methoxycarbonylallyl halides (6a and b), which were prepared starting from geranylgeraniol. The stereoselective synthesis of (±)-trans-cembranolide (II) was achieved by lactonization of 14-membered cis-intermediate (7) with inversion of the stereochemistry at C-2. (±)-Sarcophytonin B (III) was also synthesized from (±)-cis-cembranolide (I) via isomerization of the exo-cyclic double bond.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 683 - 688
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DOI: 10.3987/COM-93-S68
Pyrrole Ring Opening in 5-Nitroso- and 5-Phenylazo-1H-pyrrolotetrazoles — An Unexpected Valence Isomerism

Dietrich Moderhack* and Dirk Decker

*Institut für Phaemazeutische Chemie, Technische Universität, D-38106 Brauschweig, Germany


1,6-Disubstituted 5-nitroso-1H-pyrrolotetrazoles ring open below 20°C to give the isomeric acrylonitrile oxides. The 5-phenylazo analogs as well as 5-nitroso derivatives havingin addition an acceptor group at C-7 are stable at 20°C, but heating with the dipolarophile DMAD leads to pyrazoles and isoxazoles.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 689 - 692
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DOI: 10.3987/COM-93-S75
Reactions of Some 1-(4,5-Dihydroimidazol-2-yl)azoles with Aroyl and Ethoxycarbonyl Isothiocyanates

Franciszek Saczewski*

*Department of Organic Chemistry, Medical Academy, 80-416 Gdansk, Poland


Three components cyclocondensations of the imidazole derivative (1c) with aroyl isothiocyanates afforded 6,7,8,8a-tetrahydro-3-aroylimidazo[1,2-a][1,3,5]triazine-2,4(3H,8H)dithiones (5a-e), while similar reaction with ethoxycarbonyl isothiocyanate led to the formation of ethyl 5-thioxo-2,3,8,9-tetrahydro-5H-diimidazo[1,2-a:1’,2;-c]-[1,3,5]triazine-6-carboxylate (10).

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 693 - 696
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DOI: 10.3987/COM-93-S78
Synthesis and Characterization of Thieno[3,4-c][1,2,5]thiadiazoles

Shoji Tanaka, Masaaki Tomura, and Yoshiro Yamashita*

*Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan


Thieno[3,4-c][1,2,5]thiadiazoles (1a-b) were synthesized and characterized based on the spectral and structural data. The most notable smctural feature of this “nonclassical” condensed thiophene is the small HOMO-LUMO separation leading to the highly amphoteric redox properties compared with the related “classical” thiophenes. The X-ray structure analysis suggested that this heterocycle has the character of a thiocarbonyl ylide. Short intermolecular S---N contacts were found in the crystal.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 697 - 700
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DOI: 10.3987/COM-93-S89
Electrocyclic Ring Closure of 1-Azatrienes as a Route to the Indolo[3,2,1-ij][1,6]naphthyridine Ring System

Andrew L. Germain, Thomas L. Gilchrist,* and Paul D. Kemmitt

*Department of Chemistry, University of Liverpool, Liverpool, L69 3BX, U.K.


t- Methods of annelation of indole across the 1- and 2-positions have been explored using both the intramolecular Heck reaction and Dieckmann cyclisation. Two examples 5 and 7 of the title ring system have been produced by the thermal cyclisation of indole-3-carboxaldehyde oximes with an akenyl substituent at C-2.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 701 - 708
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DOI: 10.3987/COM-93-S90
Lithiation Routes to Oxindoles and 2-indolinethiones: Precursors to 2,2'-Dithiobisindoles with Tyrosine Kinase Inhibitory Properties

Gordon W. Rewcastle* and William A. Denny

*Cancer Reserach Laboratory, Univerity of Auckland, School of Medicine, Private Bag 92019, Auckland, New Zealand


N-Substituted oxindoles and 2-indolinethiones can be prepared by lithiation of carboxyl protected N,2-dimethylanilines followed by quenching with CO2 or CS2 respectively. 2-Indolinethione derivatives are also available via demethylation of 2-methylthioindoles, which are prepared by lithiation of N-substituted indoles and treatment with dimethyl disulfide.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 709 - 713
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DOI: 10.3987/COM-93-S92
The Reaction of Diazines with Allyltributyltin via N-Alkoxycarbonyldiazinium Salts

Takashi Itoh, Hiroshi Hasegawa, Kazuhiro Nagata, Yuji Matsuya, and Akio Ohsawa*

*School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan


Pyridazines were allowed to react with allyltributyltin in the presence of chloroformate to give 1-alkoxycarbonyl-6-allyl- and 1-alkoxycarbonyl-4-allyldihydro-pyridazines as major and minor products, respectively. The reaction was applied to other diazines, and tetrahydro-adducts were obtained in the case of pyrimidine and pyrazine. Benzo-fused diazines also reacted in the same manner to afford the allyl-adducts in good yields.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 715 - 718
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DOI: 10.3987/COM-93-S93
Diastereoselective [2+3] Cycloadditions of Nitrones to 2-Oxazolone Heterocycles

Tadao Ishizuka, Hirofumi Matsunaga, Junji Iwashita, Takenori Arai, and Takehisa Kunieda*

*Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-hon-machi, Kumamoto 862-0973, Japan


Highly diastereoselective [2+3]cycloadditions of N-benzyl- and N-tert-butyl-α-phenylnitrones to 3-(2-substituted 7,7-dimethylbicyclo[2.2.1]heptane-1-carbonyl)-2-oxazolones are described.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 719 - 724
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DOI: 10.3987/COM-93-S96
Synthesis of (±)-Clavicipitic Acid and Its Derivatives

Masanori Somei,* Shoichi Hamamoto, Kyoko Nakagawa, Fumio Yamada, and Toshiharu Ohta

*Faculty of Pharmaceutical Scicences, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan


A formal total synthesis of (±)-clavicipitic acid was achieved in five steps from indole-3-carboxaldehyde. Syntheses of (±)-4-cyano-, (±)-4-methyl-, and (±)-4-hydroxymethyl-6-(2-methyl-1-propen-1-yl)-3,4,5,6-tetrahydro-1H-azepino[5,4,3-cd]indoles are also reported.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 725 - 728
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DOI: 10.3987/COM-93-S98
Synthesis of Thiapyrano[4,3-b]indoles by the Hetero Diels-Alder Reaction Using 3-Thioacetylindoles as a Diene

Masayuki Murase, Noriaki Nishino, Norichika Nara, Yoshimi Nakanishi, and Seisho Tobinaga*

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


A new synthesis of thiapyrano[4,3-b]indoles by the hetero Diels-Alder reactions of 3-thioacetylindoles (1) with dienophiles is described.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 729 - 733
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DOI: 10.3987/COM-93-S103
Kinetic Study of the Reduction of Methemoglobin with Ascorbate Using a COBAS-FARA Centrifugal Analyzer

Kilian Dill* and Evelyn L. McGown

*Molecular Device Corporation, 4700 Bohannon Drive, Menlo Park, CA, 94025, U. S. A.


The reduction-kinetics of methemoglobin with ascorbic acid were monitored using a COBAS-FARA centrifugal analyzer. The data from the initial rates for the reduction of hemoglobin were monitored as a function of the ascorbate concentration. The results show a first order dependence of the reaction rates on the ascorbate concentration and the rate constant was found to be 1.34 x 10-2 s-1 M-1. Ascorbic acid is a one electron donor in this process and consequently forms a stable radical. The presence of oxyhemoglobin interferes with the reduction of methemoglobin by ascorbate.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 735 - 738
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DOI: 10.3987/COM-93-S110
Alkylation of 4(5)-Substituted Imidazoles

Paul Benjes and Ross Grimmett*

*Chemistry Department, University of Otago, P. O. box 56, Dunedin, New Zealand


4(5)-Substituted imidazoles were alkylated under “neutral” and alkaline conditions to give mixtures of isomers in ratios which depended on the reaction conditions, and the nature of the substituent and alkylating agents.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 739 - 742
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DOI: 10.3987/COM-93-S112
The First Total Synthesis of γ-Schizandrin and Gomisin N Having Natural Configurations

Masahide Tanaka, Toshihiro Ohshima, Hiroshi Mitsuhashi, Masao Maruno, and Takeshi Wakamatsu*

*Central Research Laboratory, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, Ibaraki, 300-11, Japan


The total syntheses of γ-schizandrin and gomisin N were achieved in a stereoselective manner. The success of these synthesis heavily depends on the stereoselective reduction of tetracyclic lactones with magnesium in methanol.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 743 - 746
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DOI: 10.3987/COM-93-S116
Direct Regioselective Formation of Polysubstituted Tetrahydrofurans from Unprotected Polyols

Hiromichi Fujioka, Hidetoshi Kitagawa, Michinori Kondo, and Yasuyuki Kita*

*Faculty of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Toyonaka, Osaka 560-0043, Japan


The reaction of unprotected polyols (tetraols, pentitol and hexitol) with trimethyl orthobenzoate in CH2Cl2-MeOH afforded polysubstituted tetrahydrofurans in a one-pot synthesis.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 747 - 750
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DOI: 10.3987/COM-93-S129
A Straightforward Synthesis of (±)-4-Amino-4-deoxyerythrose via Its Bisulfite Anomer

Jean-Bernard Behr, Albert Defoin, and Jacques Streith*

*Ecole Nationale Supérieure de Chimie de Mulhouse, Université de Haute Alsace, 3, Rue Alfred Werner 68093 Mulhouse Cedez, France


Hetero-Diels-Alder reaction of N-butadienyl-2-pyrrolidone (1a) with acylnitroso dienophile (3) led with very high regioselectivity to the racemic cycloadduct (6). A sequence of stereospecific reactions, as well as some protection/deprotection steps, gave the bisulfite derivative (2b) of (±)-4-amino-4-deoxyerythrose (2a) as a single and crystalline anomer. Asymmetric induction as applied to the Diels-Alder cycloaddition step with various N-butadienylpyroglutamate esters (1b-e) permitted to work out optimal experimental conditions, the best d.e. value being 76%.

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Communication | Special issue | Vol 37, No. 2, 1994, pp. 751 - 757
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DOI: 10.3987/COM-93-S131
Chiral Nucleofugals: Synthesis and Structure of Functionalised Acetals Derived from D-(+)-Glucose

Pierre Duhamel,* Gerard Plé, and Jean-Yves Valnot

*Université de Rouen, Faculté des Sciences, URA CNRS DO 464et IRCOF, F-76821 Mont saint Aignan, France


D-(+)-Glucose derived iodoacetals (1) (Y= I) of known absolute configuration have been synthesized and their behaviour towards nucleophilic substitution was studied as a model for the synthesis of precursors of chiral nucleofugals with a pendant ligand.

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 759 - 774
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DOI: 10.3987/COM-93-S43
Synthesis of 2H-1-Benzopyrans from Aryllithium and α,β-Unsaturated Aldehydes

Raymundo Cruz-Almanza,* Francisco Pérez-Flores, and Cristina Lemini

*Instituto de Química, Universidad Nacional Autónama de México, Circuito Exterior, Ciudad Universitaria, Coyoacán 04510 Mexico, D.F., Mexico


The synthesis of 2,2-dialkyl-2H-1-benzopyrans (23), (25), (27), (30), (31) and (29) was performed employing the 1,2-addition reaction of aryllithium salts to cyclocitral, 3-methyl-2-butenal, citral and farnesal respectively. Subsequent deprotection with a Mexican bentonitic earth (Tonsil) in wet acetone was followed by ring closure reaction as the key step. Interesting intermediate products were isolated in the formation of benzopyrans (30) and (31).

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 775 - 782
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DOI: 10.3987/COM-93-S50
An Activated Trifluoromethyl Group as a Synthon for 2-Substituted Benzothiazole and Benzoxazole

Alexander S. Kiselyov, Maryam Hojjat, Koen Van Aken and Lucjan Strekowski*

*Department of Chemistry, Georgia State University, Atlanta, GA 30303, U.S.A.


Dianions derived from 2-mercaptoaniline and 2-hydroxyaniline are cyclized to 2-substituted benzothiazole and benzoxazole, respectively, in the reaction with ortho or para trifluommethyl-substituted anilines and quinolinamines that involves the CF3 group. The carbon atom of the CF3 group becomes C-2 of the five-membered ring system. Synthesis of 3-trifluoromethylquinoline-4-amine and 5-trifluoromethylquinoline-6-amine is also reported.

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 783 - 792
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DOI: 10.3987/COM-93-S53
Synthesis of Desmethyl Tiagabine

Mukund S. Chorghade,* Peter Ellegaard, Elaine C. Lee, Hans Petersen, and Per Olaf Sørensen

*Department 54P, Abbott Laboratories, Abbott Park, N. Chicago, IL60064, U.S.A.


The title compound has been investigated as one in a series of novel and selective GABA uptake inhibitors that exhibit potent anti-convulsant effects. Versatile syntheses have been developed for the preparation of this compound in excellent yields. Key steps are a Grignard reaction followed by ring opening with simultaneous dehydration and bromination of a hydroxymethyl cyclopropane with bromotrimethylsilane; displacement of bromine with ethyl R-(-)-piperidine-3-carboxylate and an acid or base catalyzed hydrolysis of the ester moiety.

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 793 - 805
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DOI: 10.3987/COM-93-S55
Preparation of New Thiohydroxamic Acid Derivatives: Synthesis of Substituted 1-Hydroxy-1,2-dihydoroimidazole-2-thiones

Derek H. R. Barton, Ching-Yu Chern, and Catherine Tachdjan*

*Department of Chemistry, Texas A & M University, College Station, Texas 77843-3255, U.S.A


A general method for the synthesis of the title compounds is reported. The N-phenacylarylamines (11), prepared from the corresponding phenacyl bromides (9) and arylamines (10), give the thiono (or dithio) carbamates (12) on treatment with phenoxythionocarbonyl or thiophenoxythionocarbonyl chlorides and potassium carbonate in dichloromethane. The desired thiohydroxamic acids (13) are obtained by heating compounds (12) with hydroxylamine hydrochloride in pyridine/ethanol.

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 807 - 814
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DOI: 10.3987/COM-93-S58
A Synthetic Bilirubin in a Porphyrin-like Conformation

Ki-Oh Hwang and David A. Lightner*

*Department of Chemistry, University of Nevada, Reno, Nevada 89557-0020, USA


An analog of bilirubin is held in a porphyrin-like shape by an N21,N24-methanobridge. In this conformation, the two propionic acid groups cannot participate in intramolecular hydrogen bonding, and the pigment is thus much more polar and hydrophilic than bilirubin. The uv-visible spectra (εmax 20,400, λmax 381 nm in benzene and εmax 23,800, λmax 385 nm) are nearly invariant over the solvent polarity range. Circular dichroism of the pigment complex with human serum albumin gives a weak bisignate Cotton effect: δεmax422 = -4.7, δεmax366 = +3.7 in pH 7.4 buffer.

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 815 - 822
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DOI: 10.3987/COM-93-S66
An Unusual Aromatization of Hantzsch-Type 4-Antipyryl-1,4-dihydropyridines

Jean-Jacques Vanden Eynde,* Annie Mayence, André Maquestiau, and Ernst Anders

*Organic Chemistry Laboratory, University of Mons-Hainaut, Place du Parc 20, B-7000 Mons, Belgium


Under acidic conditions, Hantzsch-type 4-antipyryl-1,4-dihydropyridines undergo an elimination of the 4-substituent to yield 4-unsubstituted pyridines and antipyrine. The mechanism and the scope of the reaction are discussed.

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 823 - 831
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DOI: 10.3987/COM-93-S67
Ring Opening of 4-Chloroquinazoline into 2-Arylmethyleneaminobenzonitrile by Grignard Reaction

Akira Miyashita,* Takami Sasaki, Etsuo Oishi, and Takeo Higashino

*School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan


The treatment of 4-chloroquinazoline (1) with arylmagnesium bromide (3) in tetrahydrofuran (THF) resulted in the formation of 2-arylmethyleneaminobenzonitrile (2). Continued reaction of ring opening of 1 and subsequent hydrolysis of the products (2) afforded the corresponding arenecarbaldehydes (4).

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 833 - 838
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DOI: 10.3987/COM-93-S70
Two New Xanthones in the Underground Part of Calophyllum inophyllum

Munekazu Iinuma,* Hideki Tosa, Toshiyuki Tanaka, and Shigetomo Yonemori

*Department of Pharmacognosy, Gifu Pharmaceutical University, 6-1 Mitahora-higashi 5-chome, Gifu 502-8585, Japan


From the root bark of Calophyllum inophyllum L. (Guttiferae), a new xanthone named caloxanthone C (1) and 4-hydroxyxanthone (2), and from the heartwood of root, a new xanthone 1-hydroxy-2-methoxyxanthone (3) in addition to three known xanthones [1,2-dimethoxy- (4), 2-hydroxy-1-methoxy- (5)], and 6-deoxyjacareubin (6) were isolated. The structures were characterized by means of a spectroscopic analysis.

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 839 - 845
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DOI: 10.3987/COM-93-S72
A Synthesis of (±)-Pinoresinol and Its Related Compound Using Potassium Persulfate (K2S2O8) Oxidation of Benzoylacetates

Jun Maruyama, Miho Kobayashi, Masaaki Miyashita, Isao Kouno, and Hiroshi Irie*

*Faculty of Pharmaceutical Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan


A synthesis of (±)-pinoresinol has been accomplished by application of the oxidative coupling reaction of benzoylacetate with potassium persulfate as a key step.

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 847 - 857
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DOI: 10.3987/COM-93-S73
A Synthesis of 2-Oxo-2H-pyrano-[2,3-f]quinoline Derivatives

Simona Fajgelj, Ljubo Golic, Branko Stanovnik,* and Miha Tisler

*Department of Chemistry, University of Ljubljana, Murnikova 6, P. O. Box537 61000 Ljubljana, Slovenia


A synthesis of some derivatives of 2-oxo-2H-pyrano[2,3-f]quinoline from 5,8-quinolinequinone and dialkyl 2-aminofumarate is described.

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Paper | Special issue | Vol 37, No. 2, 1994, pp. 859 - 867
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DOI: 10.3987/COM-93-S74
Chlorination of 5-[2-(N-Silylamino)vinyl]isothiazole and Related Derivatives with N-Chlorosuccinimide. Inhibition of Ring-Transformation (Bond Switch) by Steric Hindrance

Katsuo Ohkata, Yoshihiko Ohyama, and Kin-ya Akiba*

*Department of Chemistry, Faculty of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-hiroshima, Hiroshima 739-8526, Japan


The selective monochlorination of 5-[2-(N-silylamino)vinyl]isothiazoles (1a,b) and their related compounds (1c,d, 2a-g, 3a-c, and 4a,b) with N-chlorosuccinimide is described. Chlorination of 1a,b occurred at vinyl carbon to give 5a,b and the geometry was determined to be Z-isomer according to spectral data. It is noteworthy that 1d smoothly occurred bond switch at room temperature but 5d did not ring-transform under the same conditions.

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66 data found. 1 - 30 listed Next Last